JP4506600B2 - Toner for developing electrostatic image, image forming method, and method for producing toner for developing electrostatic charge - Google Patents

Description

The present invention is a copying machine, a printer, an electrophotographic apparatus to toner and may developing electrostatic images utilizing utilizing an electrophotographic process such as a facsimile, images forming method, and a method of manufacturing a toner for developing an electrostatic image.

A method of visualizing image information through an electrostatic charge image, such as electrophotography, is currently widely used in various fields. In the electrophotographic method, an electrostatic image is developed on an image carrier through a charging process, an exposure process, and the like, and the electrostatic image is visualized through a transfer process, a fixing process, and the like.

As the developer used here, a two-component developer comprising a toner and a carrier and a one-component developer using a magnetic toner or a non-magnetic toner alone are known. As a method for producing a toner, a kneading and pulverizing method is generally used in which a thermoplastic resin is melt-kneaded together with a release agent such as a pigment, a charge control agent, and a wax, and after cooling, is finely pulverized and classified. In these toners, if necessary, inorganic and organic fine particles for improving fluidity and cleaning properties may be added to the toner particle surface. Although these methods can produce very good toners, they have several problems as described below.

  In the ordinary kneading and pulverizing method, the toner shape and the surface structure of the toner are indeterminate, and although it varies slightly depending on the pulverization properties of the materials used and the conditions of the pulverization process, it is difficult to control the intentional toner shape and surface structure. . In the kneading and pulverizing method, the range of material selection is limited. Specifically, the resin colorant dispersion must be sufficiently brittle and capable of being finely pulverized by an economically possible manufacturing apparatus. However, if the resin colorant dispersion is made brittle in order to satisfy such requirements, fine powder may be further generated or the toner shape may be changed due to mechanical shearing force applied in the developing machine. Due to these effects, in the two-component developer, the charging deterioration of the developer due to the adhesion of fine powder to the carrier surface is accelerated, and in the one-component developer, toner scattering occurs due to the expansion of the particle size distribution. Deterioration in developability due to changes in image quality tends to cause image quality degradation. In addition, when a toner is formed by adding a large amount of a release agent such as wax, exposure to the release agent on the surface is often affected by the combination with a thermoplastic resin.

In particular, in the case of a combination of a resin having increased elasticity due to a high molecular weight component and slightly pulverized resin and a brittle wax such as polyethylene or polypropylene, exposure of these wax components is often observed on the toner surface. This is advantageous for releasability at the time of fixing and cleaning of untransferred toner from the image carrier, but since the polyethylene on the surface layer is easily transferred by mechanical force, contamination of the developing roll, image carrier and carrier is prevented. It tends to occur, leading to a decrease in reliability.
Furthermore, due to the irregular shape of the toner, the fluidity may not be sufficient even with the addition of a fluidity aid, and over time due to the movement of fine particles on the toner surface to the toner recess due to mechanical shearing force during use. The developability, transferability, and cleaning properties deteriorate due to the decrease in fluidity and the embedding of the fluidity aid in the toner. Further, when the toner collected by cleaning is returned to the developing machine and used again, the image quality is likely to further deteriorate. If the flow aid is further increased in order to prevent these, black spots are generated on the image carrier and the aid particles are scattered.

As described above, in the electrophotographic process, in order to stably maintain the performance of the toner even under various mechanical stresses, the surface hardness can be maintained without suppressing the exposure of the release agent to the surface or the fixing property. In addition, it is necessary to improve the mechanical strength of the toner itself and to achieve both sufficient charging and fixing properties.
Further, in recent years, the demand for higher image quality has increased, and in particular for color image formation, there has been a significant tendency to reduce the diameter of toner in order to achieve high-definition images. However, in the conventional simple size reduction with the particle size distribution, the presence of the fine powder side toner causes the problem of carrier and image carrier contamination and toner scattering, and it is possible to achieve high image quality and high reliability at the same time. Have difficulty. For this purpose, it is necessary that the particle size distribution can be sharpened and the particle size can be reduced.

  In recent years, in digital full-color copiers and printers, a color image original is separated by B (blue), R (red), and G (green) filters, and then the dot diameter of 20 to 70 μm corresponding to the original original is used. The latent image is developed using Y (yellow), M (magenta), C (cyan), and Bk (black) developers using a subtractive color mixing effect, but a larger amount of developer than conventional black and white machines. Uniform chargeability, sustainability, toner strength, and sharpness of particle size distribution are becoming more and more important because it is necessary to transfer the toner and to cope with a smaller dot diameter. Further, in view of speeding up and energy saving of these machines, further low temperature fixability is required. Also from these points, the agglomerated and coalesced toner suitable for the production of a small particle size with a sharp particle size distribution has excellent characteristics. The toner mounted on the full color machine needs to be sufficiently mixed with a large amount of toner, and improvement of color reproducibility and OHP transparency are essential at this time.

  Generally, a polyolefin-based wax is internally added to the release agent component for the purpose of preventing low temperature offset during fixing. At the same time, a small amount of silicone oil is uniformly applied to the fixing roller to improve the high temperature offset property. For this reason, silicone oil adheres to the output transfer material that is output, and there is an unpleasant feeling of stickiness when it is handled, which is not preferable.

For this reason, an oilless fixing toner in which a large amount of a release agent component is included in the toner has been proposed (see, for example, Patent Document 1).
However, in this case, the releasability can be improved to some extent by adding a large amount of the release agent, but the compatibility of the binder component and the release agent occurs, and the bleeding of the stable release agent is not uniform. Therefore, it is difficult to obtain the stability of peeling. Furthermore, since the means for controlling the cohesive force of the binder resin of the toner depends on the glass transition temperature (Tg) and the mass average molecular weight (Mw) of the binder, the spinnability and cohesiveness during toner fixing are directly controlled. It is difficult. Furthermore, the free component of the release agent may cause charging inhibition.

  As a method for solving these problems, a method of obtaining the rigidity of the binder resin by adding a high molecular weight component (Patent Document 2 and Patent Document 3), or introduction of chemical crosslinking as shown in Patent Document 4 and Patent Document 5 There has been proposed a method for improving the releasability in oil-less fixing, which compensates for the above and consequently reduces the spinnability at the fixing temperature of the toner.

On the other hand, regarding the release agent, an approach to the problems of the oilless fixability, particularly oilless peelability, OHP transparency in a full-color image, or toner powder fluidity inhibition caused by a release material has been studied and proposed. ing. Specifically, for the purpose of improving oil peelability, for example, as shown in Patent Document 6, the melting point of the release agent is set to an intermediate temperature range, and an amorphous or low crystalline release agent such as ester wax is used. By applying this, the melt viscosity is kept low, oilless peelability is realized, and the OHP transparency inhibition of full-color images is suppressed by this low crystal structure.
However, in this case, the release agent component often causes plasticization in the binder resin component, and as a result, the rheology of the resin at the time of fixing is lowered, so that the oilless releasability of the toner is lowered. For this reason, it is indispensable to introduce a cross-linked structure on the surface of the binder resin itself, to increase the molecular weight and the glass transition temperature (Tg), to suppress the decrease in peelability due to plasticization, and to introduce a large amount of release agent Therefore, as a result, the image gloss is lowered and the transparency of the OHP is often impaired.

  On the other hand, in electrophotography, an electrostatic charge image is developed on an image carrier by a charging process, an exposure process, etc., and the toner on the fixing substrate after the transfer process is heated by a fixing member heated in the fixing process. As a result, it is melted and fixed on the surface of the fixing substrate. In the fixing step, it is known that the toner is not fixed onto the fixing base unless not only the toner but also the fixing base is heated to a necessary temperature by the fixing member. If the fixing substrate is not sufficiently heated, only the toner is melted by the heating from the fixing member, and a so-called cold offset is generated in which the toner adheres to the fixing member. In addition, when the heating is excessive, the viscosity of the toner decreases, and so-called hot offset occurs in which a part or all of the fixing layer adheres to the fixing member side. Therefore, a fixing region is required in which neither the cold offset nor the hot offset occurs due to heating from the fixing member.

On the other hand, as the demand for energy saving increases, it is necessary to lower the fixing temperature of the toner in order to save power in the fixing process that occupies a certain amount of power and expand the fixing area. By lowering the toner fixing temperature, in addition to the power saving and expansion of the fixing area, the waiting time until the fixing temperature on the surface of the fixing roll when power is input, so-called warm-up time is shortened, fixing The life of the roll can be extended.
However, in order to lower the fixing temperature of the toner, lowering the Tg (glass transition temperature) of the resin causes the heat resistant storage stability and fixing strength to deteriorate, and the F _1/2 temperature decreases due to the lower molecular weight of the resin. However, problems such as occurrence of hot offset and excessive gloss (gloss controllability) occur. For this reason, by controlling the thermal characteristics of the resin itself, it has not yet been possible to obtain a toner having excellent low-temperature fixability and excellent heat-resistant storage stability and offset resistance.

  In order to cope with such low-temperature fixing, attempts have been made to use a polyester resin having excellent low-temperature fixability and relatively good heat-preserving stability in place of styrene-acrylic resins that have been widely used in the past (for example, Patent Document 7). ~ 12). In addition, there is an attempt to add a specific non-olefinic crystalline polymer having sharp melt properties at the glass transition temperature in the binder for the purpose of improving low temperature fixability (see Patent Document 13). Is insufficient.

  On the other hand, in order to achieve both low-temperature fixing and toner storage stability, it has been investigated that the toner has a so-called sharp melt property in which the viscosity of the toner rapidly decreases in a high-temperature region while keeping the glass transition point of the toner at a higher temperature. ing. In general, the resin used in the toner usually has a certain range of glass transition point, molecular weight, etc., so in order to obtain the sharp melt property, it is necessary to extremely align the resin composition and molecular weight, In order to obtain the resin, it becomes necessary to adjust the molecular weight of the resin by using a special production method or by treating the resin with chromatography or the like. In this case, the cost for producing the resin must be high. In addition, unnecessary resin is generated at that time, which is not preferable from the viewpoint of environmental protection in recent years.

Thus, as a method for lowering the toner fixing temperature, it has been proposed to use a crystalline resin as a binder resin (see, for example, Patent Documents 14 to 18). According to these techniques, studies using various crystalline resins have been made. Although these methods can lower the fixing temperature, these resins can give good results with respect to low-temperature fixing properties, but the strength of the fixed image is low, for example, writing on the image with pencils. When such stress is applied, the image is destroyed and reliability is poor.
In other words, it has been difficult for conventional techniques to satisfy both the low-temperature fixability and the stability in long-term use.
JP-A-5-061239 Japanese Patent Laid-Open No. 4-69666 Japanese Patent Laid-Open No. 9-254841 JP 59-218460 A JP-A-59-218459 JP-A-6-337541 JP 60-90344 A JP-A 64-15755 Japanese Patent Laid-Open No. 2-82267 JP-A-3-229264 JP-A-3-41470 JP-A-11-305486 JP 62-63940 A JP 05-001217 A Japanese Patent Laid-Open No. 06-148936 Japanese Patent Laid-Open No. 06-194874 JP 05-005056 A Japanese Patent Laid-Open No. 05-112715

In view of the above problems, the present invention has been made to solve the problems.
That is, the present invention is excellent in low-temperature fixing property, and to provide stable electrostatic charge image developing toner in long-term use, images forming method, and a method for producing a toner for developing an electrostatic image.

As a result of intensive studies to solve the above-mentioned problems of the prior art, the present inventors have found that the above object can be achieved by the following contents. That is, the present invention
<1> In a nonmagnetic electrostatic charge developing toner containing at least a polyester resin, a colorant , and a release agent , the average specific gravity (A) of the electrostatic charge developing toner in the electrostatic charge developing toner the content of a × 0.95 or lower density toner Te (B) is a toner for electrostatic charge development, characterized by satisfying the following formula (1).
0.1% by mass ≦ B ≦ 1.5% by mass (1)

<2> The electrostatic charge developing toner according to <1>, wherein the electrostatic charge developing toner is prepared by a wet manufacturing method.
<3> The polyester resin is a toner for developing an electrostatic image according to said crystalline polyester resin der Rukoto <1> or <2>.

< 4 > The electrostatic charge developing toner according to any one of <1> to < 3 > has a volume average particle size distribution index GSDv of 1.30 or less and a number of the volume average particle size distribution index GSDv The ratio (GSDv / GSDp) to the average particle size distribution index GSDp is 0.95 or more.
< 5 > An electrostatic latent image forming step of forming an electrostatic latent image on a precharged image carrier, and developing the electrostatic latent image with a developer containing toner, so that a toner image is formed on the image carrier. A developing step for transferring the toner image formed on the image carrier, a transfer step for transferring the toner image onto the transfer member, and a toner image on the image carrier after the toner image is transferred onto the transfer member. In the image forming method, comprising: a cleaning step of removing the remaining toner from the image bearing member; and a fixing step of fixing the toner image transferred onto the transfer member; An image forming method comprising the electrostatic charge developing toner according to any one of to < 4 >.
<6> The method for producing a toner for electrostatic charge development according to any one of <1> to <4>, wherein a resin fine particle dispersion in which the first resin fine particles containing the polyester resin are dispersed; The colorant particle dispersion in which the colorant is dispersed and the release agent particle dispersion obtained by emulsifying the release agent are mixed at a rotational speed and a dispersion time that satisfy the following formula (2). A first aggregating step for forming core agglomerated particles including the first resin fine particles, the colorant, and the release agent particles; and forming a shell layer including second resin fine particles on the surface of the core agglomerated particles. And aggregating and coalescing by heating the core / shell aggregated particles to the glass transition temperature of the first resin fine particles or the second resin fine particles. An electrostatic charge developing toner having a fusion and unification step It is a manufacturing method of chromatography.
10,000 (rpm · min) ≤ number of revolutions × dispersion time ≤ 100,000 (rpm · min) · · · Equation (2)
<7> The method for producing an electrostatic charge developing toner according to any one of <1> to <4>, wherein the resin fine particle dispersion is obtained by dispersing the first resin fine particles including the polyester resin. The colorant particle dispersion in which the colorant is dispersed and the releaser particle dispersion obtained by emulsifying the releaser are mixed to obtain the first resin fine particles, the colorant, and the releaser. A first aggregating step for forming core agglomerated particles including particles, and a second aggregating step for forming core / shell agglomerated particles by forming a shell layer containing second resin fine particles on the surface of the core agglomerated particles, An average of the toner and the coalescing and coalescing step by which the core / shell aggregated particles are fused and coalesced by heating to above the glass transition temperature of the first resin fine particles or the second resin fine particles. Specific gravity (A) x 0.95 specific gravity Removing the floating toner after the toner dispersion liquid was poured for 24 hours left in um solution, a method for producing a toner for electrostatic charge development with.

According to the present invention, the content (B) of the low specific gravity toner of A × 0.95 or less with respect to the average specific gravity (A) of the electrostatic charge developing toner in the electrostatic charge developing toner is expressed by the above formula (1). ) by adjusting to meet, excellent low-temperature fixing property, a stable electrostatic charge image developing in long-term use toner, images forming method, and can provide a method for producing a toner for developing an electrostatic image, an effect that is obtained Be

Hereinafter, the present invention will be described in detail.
<Toner for electrostatic image development>
The electrostatic charge developing toner of the present invention has an average specific gravity of the electrostatic charge developing toner in a nonmagnetic electrostatic charge developing toner containing at least a binder resin, which is a polyester resin, a colorant , and a release agent. The content (B) of the low specific gravity toner of A × 0.95 or less with respect to (A) satisfies the following formula (1).
0.1% by mass ≦ B ≦ 1.5% by mass (1)

Electrostatic latent image developing toner of the present invention, at least a binder resin, a colorant, and Ru toner der electrostatic charge development of the non-magnetic constructed from the release agent. Electrostatic latent image developing toner is produced by wet-type process. The material ratio in each of the produced electrostatic charge developing toners does not have a uniform value among the toners but has a different composition distribution. As a result of intensive studies, the present inventors have found that when this composition distribution is within a certain range, a toner for developing an electrostatic charge that is excellent in low-temperature fixability and stable for long-term use can be obtained.
In the present specification, the electrostatic charge developing toner of the present invention will be referred to as “toner” or “electrostatic charge developing toner” as appropriate.

Here, among the binder resin, the colorant , and the release agent contained in the electrostatic charge developing toner, the release agent has the lightest specific gravity, and the specific gravity is 1 or less. Next, the resin having a low specific gravity is a binder resin, and the specific gravity is 1.1 to 1.3. The thing with the highest specific gravity is a colorant , and the specific gravity is 1.5 or more and 1. For this reason, the content of the release agent in comparison with the ratio of the respective materials for producing the electrostatic charge developing toner, that is, the binder resin, the colorant , and the release agent (hereinafter referred to as the charged material ratio). A high toner has a lower specific gravity than the average specific gravity of all the electrostatic charge developing toners produced.

As will be described in detail later, in an electrophotographic image forming apparatus, an electrostatic latent image on an image carrier having an electrostatic latent image corresponding to the image on the surface is developed with a developer containing toner for developing electrostatic charge. Thus, a toner image corresponding to the electrostatic latent image is formed on the image carrier, and the toner image is transferred to a transfer medium such as a recording medium and then fixed on the transfer medium. The electrostatic charge developing toner remaining on the image carrier (toner that has not been transferred to the transfer member) is removed from the image carrier by a cleaning blade, a cleaning brush, or the like (cleaning step).
The release agent contained in the electrostatic charge developing toner is a useful material for stabilizing the toner fixing property. However, when fixing the toner image transferred onto a transfer medium such as a recording medium, the toner is used. The compositional uneven distribution between them is not a big problem. When fixing the toner image on the transfer target, if the release agent is averagely dispersed as a whole of the macro toner image rather than the deviation of the material ratio between the toners, the fixing property is not lowered.
On the other hand, in the image forming apparatus, after the toner image formed on the image carrier is transferred to the transfer target, the toner remaining on the image carrier is removed by a cleaning blade, a cleaning brush, or the like in the cleaning process. However, in this removal, uneven composition between the toners becomes a problem. Specifically, the release agent cannot hold a large amount of charge compared to the binder resin, and the toner having a higher release agent content has a lower charge amount and is difficult to be transferred on the image carrier. Easy to remain. That is, it can be said that the toner to be cleaned has a high content of the release agent.

  In the cleaning process, there is a toner in which the surface of the toner is destroyed because a strong mechanical force is applied to the toner, and the release agent inside the toner is rubbed against the surface of the image carrier. At this time, if the filming amount is small, it is as if it is coated with a thin layer (hereinafter referred to as filming), and the coefficient of friction on the surface of the image carrier is reduced and the cleaning property is improved. In the case of filming, normal toner also adheres and accumulates on the film, so that normal development is not performed, white spots of the image occur, and the image itself is fogged due to poor cleaning itself. There is a problem.

Therefore, the uneven distribution of the content of the release agent between the toners is not too small, and the optimal uneven distribution is not necessary. The release agent content distribution (uneven distribution) of each toner can be obtained by obtaining the toner specific gravity distribution by utilizing the fact that the specific gravity of the release agent is the lightest among the toner constituting materials.
Usually, the specific gravity of what is called a mold release agent is 1 or less, and is 0.80 to 0.95. On the other hand, what is used for binder resin is 1.1-1.35.

The content (B) of the low specific gravity toner of A × 0.95 or less with respect to the average specific gravity (A) of the electrostatic charge developing toner in the electrostatic charge developing toner is from 0.1% by mass to 1.5%. The mass% is preferably 0.2% by mass or more, more preferably 0.2% by mass or more and 1.0% by mass or less, and particularly preferably 0.2% by mass or more and 0.8% by mass or less.
When the content of the low specific gravity toner in the total amount of electrostatic charge developing toner is less than 0.1% by mass, filming of the image carrier does not occur, but the coefficient of friction between the image carrier and the cleaning blade or the cleaning brush is low. It becomes high and wear of a cleaning blade and a cleaning brush, and chipping occur, and it cannot withstand long-term use. On the other hand, when the content is more than 1.5% by mass, filming on the image carrier occurs during long-term use, resulting in a low-quality image in which white spots or the like exist.

<Determination of specific gravity distribution of toner for electrostatic charge development>
Next, how to obtain the specific gravity distribution of the electrostatic charge developing toner will be described.

For example, 40 ml of ion-exchanged water is charged into a 100 ml graduated cylinder, and a certain amount (W1) of potassium iodide (specific gravity 3.3) is further charged. The deposition of this potassium iodide solution is designated as V1. On the other hand, 0.5 g of toner is added to 10 g of a 1% surfactant aqueous solution and stirred, and the toner dispersion completely wetted is added to the potassium iodide solution and stirred for 24 hours. In this case, the total specific gravity of the aqueous potassium iodide solution is represented by the following formula (2).

[40 g (ion exchange water) + W1 (g) +10 g (1% surfactant aqueous solution)] / [V1 (ml) +10 (ml)] Formula (2)

  The toner that is not precipitated after 24 hours at room temperature and is floating is separated together with the aqueous solution with a dropper or the like, and suction filtered using a 0.2 μm membrane filter. During the filtration, ion-exchanged water is also used to wash the toner so that no potassium iodide solution remains. The toner amount thus separated and secured is dried and weighed, and compared with the amount of toner 0.5 g at the time of preparation, the mass% of the toner having a specific gravity equal to or lower than that of the potassium iodide solution can be obtained.

  By changing the amount of potassium iodide input in this way, the specific gravity of the potassium iodide solution is changed, and the amount of floating toner for each solution is measured, so that the relationship of the amount of floating toner to each specific gravity is obtained. The specific gravity distribution can be obtained. The specific gravity of the solution in which 50% of the toner floats is defined as the average specific gravity.

Next, the structure and manufacturing method of the electrostatic charge developing toner of the present invention will be described.
The toner for developing an electrostatic charge of the present invention contains at least a binder resin, a colorant , and a release agent , and other components as necessary. The toner for developing an electrostatic charge according to the present invention will be described in detail with respect to each constituent component.

<Binder resin>
The binder resin used for the electrostatic charge developing toner of the present invention is not particularly limited, and a known resin material can be used. In particular, a crystalline polyester resin having sharp melt properties is useful for imparting low-temperature fixability.

In the present invention, the “crystalline polyester resin” refers to a resin having a clear endothermic peak instead of a stepwise endothermic amount change in differential scanning calorimetry (DSC). Moreover, in the case of the polymer which copolymerized the other component with respect to the said crystalline polyester main chain, when another component is 50 mass% or less, this copolymer is also called crystalline polyester resin.
The crystalline polyester resin and all other polyester resins are synthesized from a polyvalent carboxylic acid component and a polyhydric alcohol component. In the present invention, a commercially available product may be used as the polyester resin, or an appropriately synthesized product may be used.

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

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

  Moreover, as an acid component, it is preferable that the dicarboxylic acid component which has a sulfonic acid group other than the above-mentioned aliphatic dicarboxylic acid and aromatic dicarboxylic acid is contained. The dicarboxylic acid having a sulfonic acid group is effective in that it can favorably disperse a coloring material such as a pigment. Further, when the entire resin is emulsified or suspended in water to form fine particles, if there are sulfonic acid groups, as described later, emulsification or suspension can be performed without using a surfactant.

  Examples of the dicarboxylic acid having a sulfone group include, but are not limited to, 2-sulfoterephthalic acid sodium salt, 5-sulfoisophthalic acid sodium salt, and sulfosuccinic acid sodium salt. Moreover, these lower alkyl esters, acid anhydrides, etc. are also mentioned. The divalent or higher carboxylic acid component having a sulfonic acid group is contained in an amount of 0 to 20 mol%, preferably 0.5 to 100 mol%, based on all carboxylic acid components constituting the polyester. If the content is too low, the stability of the emulsified particles with time deteriorates. On the other hand, if the content exceeds 10 mol%, not only the crystallinity of the polyester resin is lowered, but also the process of fusing the particles after aggregation is adversely affected. There is a problem that it becomes difficult to adjust.

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

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

  Specific examples of the aliphatic diol suitably used for the synthesis of the crystalline polyester used for the electrostatic charge developing toner of the present invention include ethylene glycol, 1,3-propanediol, and 1,4-butanediol. 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,14-eicosandecanediol, etc., but are not limited thereto. Absent. Of these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability.

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

  Among the polyhydric alcohol components, the content of the aliphatic diol component is preferably 80 mol% or more, and more preferably 90% or more. When the content of the aliphatic diol component is less than 80 mol%, the crystallinity of the polyester resin is lowered and the melting point is lowered, so that toner blocking resistance, image storage stability, and low-temperature fixability may be deteriorated. is there.

  If necessary, monovalent acids such as acetic acid and benzoic acid and monovalent alcohols such as cyclohexanol benzyl alcohol can also be used for the purpose of adjusting the acid value and hydroxyl value.

  The method for producing the crystalline polyester resin is not particularly limited, and can be produced by a general polyester polymerization method in which an acid component and an alcohol component are reacted. Examples thereof include direct polycondensation and transesterification. They are manufactured using different types of monomers.

  The production of the crystalline polyester resin can be carried out at a polymerization temperature of 180 to 230 ° C., and the reaction is carried out while reducing the pressure in the reaction system as necessary to remove water and alcohol generated during condensation. When the monomer is not dissolved or compatible at the reaction temperature, a solvent having a high boiling point may be added as a solubilizer and dissolved. In the polycondensation reaction, the dissolution auxiliary solvent is distilled off. In the case where a monomer having poor compatibility exists in the copolymerization reaction, it is preferable that the monomer having poor compatibility and the monomer and the acid or alcohol to be polycondensed are condensed in advance and then polycondensed together with the main component.

  The preparation of the crystalline polyester resin fine particle dispersion can be carried out by adjusting the acid value of the resin, emulsifying and dispersing using an ionic surfactant, and the like.

  Catalysts that can be used in the production of the crystalline polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metals such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium Compounds: Phosphorous acid compounds, phosphoric acid compounds, amine compounds, and the like, and specific examples include the following compounds.

  For example, sodium acetate, sodium carbonate, lithium acetate, lithium carbonate, calcium acetate, calcium stearate, magnesium acetate, zinc acetate, zinc stearate, zinc naphthenate, zinc chloride, manganese acetate, manganese naphthenate, titanium tetraethoxide, titanium Tetrapropoxide, titanium tetraisoproxide, titanium tetrabutoxide, antimony trioxide, triphenylantimony, tributylantimony, tin formate, tin oxalate, tetraphenyltin, dibutyltin dichloride, dibutyltin oxide, diphenyltin oxide, zirconium tetrabutoxide, naphthenic acid Zirconium, zirconyl carbonate, zirconyl acetate, zirconyl stearate, zirconyl octylate, germanium oxide, triphenyl Sufaito, tris (2, 4-t-butylphenyl) phosphite, ethyltriphenylphosphonium bromide, triethylamine, compounds such as triphenyl amine.

  As melting | fusing point of crystalline resin, Preferably it is 50-110 degreeC, More preferably, it is 60-90 degreeC. When the melting point is lower than 50 ° C., the storage stability of the toner and the storage stability of the toner image after fixing may become a problem. There is a case.

  A crystalline resin may show a plurality of melting peaks, but in the present invention, the maximum peak is regarded as the melting point.

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

  Further, as the amorphous polymer, a known resin material can be used, but an amorphous polyester resin is particularly preferable. The amorphous polyester resin used in the present invention is obtained mainly by condensation polymerization of polyvalent carboxylic acids and polyhydric alcohols.

  When an amorphous polyester resin is used, it is advantageous in that a resin particle dispersion can be easily prepared by adjusting the acid value of the resin or by emulsifying and dispersing using an ionic surfactant. .

  Examples of polycarboxylic acids include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids, maleic anhydride, fumaric acid, succinic acid, alkenyl Examples thereof include aliphatic carboxylic acids such as succinic anhydride and adipic acid, and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. These polyvalent carboxylic acids can be used alone or in combination. Of these polyvalent carboxylic acids, it is preferable to use aromatic carboxylic acids, and in order to take a crosslinked structure or a branched structure in order to ensure good fixability, tricarboxylic or higher carboxylic acids (trimerits) It is preferable to use an acid or an acid anhydride thereof in combination.

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

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

  The polyester resin can be produced by subjecting the polyhydric alcohol and polyhydric carboxylic acid to a condensation reaction according to a conventional method. For example, the above polyhydric alcohol and polyvalent carboxylic acid, if necessary, a catalyst, and blended in a reaction vessel equipped with a thermometer, a stirrer, a flow-down condenser, and in the presence of an inert gas (such as nitrogen gas), Heat at 150 to 250 ° C. to continuously remove by-product low-molecular compounds out of the reaction system, stop the reaction when a predetermined acid value is reached, cool, and obtain the desired reactant Can be manufactured.

  Examples of the catalyst used for the synthesis of this polyester resin include esterification catalysts such as organic metals such as dibutyltin dilaurate and dibutyltin oxide, and metal alkoxides such as tetrabutyl titanate. The amount of such a catalyst added is preferably 0.01 to 1.00% by mass relative to the total amount of raw materials.

  The amorphous polymer used in the toner of the present invention has a mass average molecular weight (Mw) of 5,000 to 1,000,000 as measured by gel permeation chromatography (GPC) method of tetrahydrofuran (THF) soluble content. More preferably, it is 7000-500000, the number average molecular weight (Mn) is preferably 2000-10000, the molecular weight distribution Mw / Mn is preferably 1.5-100, more preferably 2- 60.

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

  In the present invention, the molecular weight of the resin is measured with a THF solvent using a Toso GPC / HLC-8120, a Tosoh column TSKgel SuperHM-M (15 cm), and a monodisperse polystyrene standard sample. The molecular weight was calculated using the prepared molecular weight calibration curve.

  The acid value of the polyester resin (mg number of KOH required to neutralize 1 g of resin) is easy to obtain the molecular weight distribution as described above, and it is easy to ensure the granulation property of the toner particles by the emulsion dispersion method. From the standpoint of maintaining good environmental stability (charging stability when temperature and humidity are changed) of the obtained toner, it is preferably 1 to 30 mg KOH / g. The acid value of the polyester resin can be adjusted by controlling the carboxyl group at the terminal of the polyester according to the blending ratio of the raw polyhydric carboxylic acid and polyhydric alcohol and the reaction rate. Or what has a carboxyl group in the principal chain of polyester is obtained by using trimellitic anhydride as a polyvalent carboxylic acid component.

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

  In the case of polyester, the resin fine particle dispersion can be prepared with a disperser such as a homogenizer by adjusting the acid value of the resin and neutralizing amine, and the amorphous polymer is prepared using a vinyl monomer. In this case, emulsion polymerization can be carried out using an ionic surfactant or the like to prepare a resin fine particle dispersion. In the case of other resins, those that are oily and soluble in a solvent with relatively low solubility in water If the resin is dissolved in those solvents, the resin is dispersed in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte in water, and then the solvent is evaporated by heating or decompression to evaporate the solvent. A fine particle dispersion can be prepared. Further, the amorphous resin is advantageous in that a resin particle dispersion can be easily prepared by emulsifying and dispersing in water.

  The particle size of the resin fine particle dispersion thus obtained can be measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).

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

  The softening point of the amorphous polymer is preferably in the range of 80 to 130 ° C. More preferably, it is the range of 90-120 degreeC. When the softening point is 80 ° C. or lower, the toner and the image stability of the toner after fixing and during storage are significantly deteriorated. On the other hand, when the softening point is 130 ° C. or higher, the low-temperature fixability deteriorates.

  Measurement of softening point of amorphous polymer is flow tester (manufactured by Shimadzu: CFT-500C), preheating: 80 ℃ / 300sec, plunger pressure: 0.980665MPa, die size: 1mmφ × 1mm, heating rate: 3.0 ℃ / The intermediate temperature between the melting start temperature and the melting end temperature under the condition of min.

(Release agent)
The electrostatic charge developing toner of the present invention can contain a release agent. A mold release agent is generally used for the purpose of improving mold release properties. Examples of the release agent that can be used in the electrostatic charge developing toner of the present invention are not particularly limited, and include montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, microcrystalline wax, and Fischer-Tropsch wax. Minerals such as petroleum wax, natural gas wax, and modified products thereof, low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene, silicones that exhibit a softening point upon heating, oleic acid amide, erucic acid amide, ricinoleic acid Examples include fatty acid amides such as amides and stearic acid amides, plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax and jojoba oil, and animal waxes such as beeswax. But In addition, examples of the modifying auxiliary component include higher alcohols having 10 to 18 carbon atoms and mixtures thereof, and higher fatty acid monoglycerides having 16 to 22 carbon atoms and mixtures thereof, which should be used in combination. Can do.

(Coloring agent)
There is no restriction | limiting in particular as a coloring agent used for the toner for electrostatic charge development of this invention, A well-known coloring agent is mentioned, It can select suitably according to the objective.

The yellow pigment, for example, Hansa Yellow, Hansa Yellow 10G, Benzidine Yellow G, Benzidine Yellow GR, Threne Yellow, Quinoline Yellow, Permanent Yellow NCG and the like. Red pigments include Bengala, Watch Young Red, Permanent Red 4R, Resol Red, Brilliantamine 3B, Brilliantamine 6B, Dupont Oil Red, Pyrazolone Red, Rhodamine B Lake, Lake Red C, Rose Bengal, Eoxin Red, Alizarin Lake Etc. Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, induslen blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate. Moreover, these can be mixed and used in the state of a solid solution.

  These colorants are dispersed by a known method, and for example, a rotary shear type homogenizer, a media type dispersing machine such as a ball mill, a sand mill, or an attritor, a high-pressure opposed collision type dispersing machine, or the like is preferably used.

These colorants can be dispersed in an aqueous solvent using a polar ionic surfactant and a homogenizer as described above to prepare a colorant particle dispersion.

  The colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner. The amount of the colorant added to the toner of the present invention is preferably in the range of 4 to 20 parts by mass with respect to 100 parts by mass of the resin contained in the toner.

In the production of the toner of the present invention, examples of surfactants used for emulsion polymerization, pigment dispersion, resin fine particles, release agent dispersion, aggregation, or stabilization thereof include sulfate ester salts, sulfonate salts, and phosphoric acid. Anionic surfactants such as esters and soaps, cationic surfactants such as amine salts and quaternary ammonium salts, and nonionics such as polyethylene glycols, alkylphenol ethylene oxide adducts, and polyhydric alcohols It is also effective to use a surfactant in combination, and a general means such as a rotary shear type homogenizer, a ball mill having a media, a sand mill, or a dyno mill can be used for dispersion.

―Other ingredients―
The toner of the present invention may contain other components of the binder resin, the colorant, and the release agent. There is no restriction | limiting in particular as another component, According to the objective, it can select suitably, For example, well-known various additives, such as an inorganic fine particle, an organic fine particle, a charge control agent, etc. are mentioned.
The charge control agent is used for the purpose of improving and stabilizing the chargeability. As the charge control agent, various commonly used charge control agents such as quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments can be used. In the first and second agglomeration processes and the fusion and coalescence process, a material that is difficult to dissolve in water is preferable in terms of controlling the ionic strength that affects the stability of the aggregated particles and reducing wastewater contamination.

  When inorganic fine particles are added to the toner as a charge control agent, examples of such inorganic fine particles include silica, alumina, titania, calcium carbonate, magnesium carbonate, tricalcium phosphate and other external additives on the normal toner surface. All inorganic fine particles used as can be mentioned. In this case, these inorganic fine particles can be used by being dispersed in a solvent using an ionic surfactant, a polymer acid, a polymer base or the like.

  Also, for the purpose of imparting fluidity and improving cleaning properties, after drying like normal toner, inorganic particles such as silica, alumina, titania and calcium carbonate, and resin fine particles such as vinyl resin, polyester and silicone are flow aids. As a cleaning aid, it can be added to the toner surface of the present invention by shearing in a dry state.

  Inorganic oxide fine particles added to the toner include SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO.SiO2, K2O. (TiO2) n. Al 2 O 3 .2SiO 2, CaCO 3, MgCO 3, BaSO 4, MgSO 4 and the like. Of these, silica fine particles and titania fine particles are particularly preferable. It is desirable that the surface of the inorganic oxide fine particles is previously hydrophobized. This hydrophobization treatment is more effective for improving the powder fluidity of the toner, as well as the environmental dependency of charging and the resistance to carrier contamination.

  The hydrophobic treatment can be performed by immersing the inorganic oxide fine particles in a hydrophobic treatment agent. Although there is no restriction | limiting in particular as said hydrophobic treatment agent, For example, a silane coupling agent, silicone oil, a titanate coupling agent, an aluminum coupling agent, etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together. Among these, silane coupling agents are preferable.

  As the silane coupling agent, for example, any one of chlorosilane, alkoxysilane, silazane, and a special silylating agent can be used. Specifically, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, Methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltriethoxysilane, decyltrimethoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N- ( Trimethylsilyl) urea, tert-butyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane , Γ-methacryloxypropyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-mercapto Examples thereof include propyltrimethoxysilane and γ-chloropropyltrimethoxysilane. The amount of the hydrophobizing agent varies depending on the kind of the inorganic oxide fine particles and cannot be generally defined, but is usually about 1 to 50 parts by mass with respect to 100 parts by mass of the inorganic oxide fine particles.

  The volume average primary particle size of the toner in the present invention is preferably in the range of 3 to 9 μm, and more preferably in the range of 3 to 8 μm. When the volume average primary particle size is less than 3 μm, the chargeability becomes insufficient and the developability may be lowered, and when it exceeds 9 μm, the resolution of the image is lowered.

The toner of the present invention has a volume average particle size distribution index GSDv of 1.30 or less and a ratio (GSDv / GSDp) of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is 0.95. The above is preferable.
More preferably, the product average particle size distribution index GSDv is 1.25 or less, and the ratio (GSDv / GSDp) of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is 0.97 or more. preferable.

  When the volume distribution index GSDv exceeds 1.30, the resolution of the image may decrease, and the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp (GSDv / GSDp) is If it is less than 0.95, the toner chargeability may be reduced, the toner may be scattered or fogged, and image defects may be caused.

  In the present invention, the volume average primary particle size of the toner and the values of the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp are measured and calculated as follows. First, the individual toner particle size distribution measured using a measuring instrument such as Coulter Counter TAII (manufactured by Nikka Kisha Co., Ltd.) or Multisizer II (manufactured by Nikka Kisha Co., Ltd.) is divided into individual particle size ranges (channels). A cumulative distribution is drawn from the small diameter side with respect to the volume and number of the toner particles, and the particle diameter at which accumulation is 16% is defined as volume average particle diameter D16v and number average particle diameter D16p, and the particle diameter at which accumulation is 50%. , Volume average particle diameter D50v and number average particle diameter D50p. Similarly, particle diameters that are 84% cumulative are defined as volume average particle diameter D84v and number average particle diameter D84p. At this time, the volume average particle size distribution index (GSDv) is defined as D84v / D16v, and the number average particle size index (GSDp) is defined as D84p / D16p using these relational expressions. GSDv) and number average particle size index (GSDp) can be calculated.

  The toner of the present invention preferably has a shape factor SF1 represented by the following formula (2) within a range of 110 to 130.

SF1 = ML ² / (4A / π) × 100 Formula (2)

[In the above formula (2), ML represents the maximum toner length (μm), and A represents the projected area (μm ² ) of the toner. ]

  When the shape factor SF1 is less than 110, a residual toner is generally generated in the transfer process during image formation. Therefore, it is necessary to remove the residual toner. It is easy to damage and may result in image defects. On the other hand, when the shape factor SF1 exceeds 130, when the toner is used as a developer, the toner may be destroyed due to collision with a carrier in the developing device. At this time, as a result, the fine powder increases or the release agent component exposed on the toner surface may contaminate the surface of the image bearing member and the like to impair the charging characteristics, and the occurrence of fog caused by the fine powder. May cause problems.

  The shape factor SF1 was measured as follows using a Luzex image analyzer (manufactured by Nireco Corporation, FT). First, an optical microscope image of the toner dispersed on the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projected area (A) of 50 or more toners are measured. The square of the maximum length / (4 × projection area / π), that is, ML2 / (4A / π) was calculated, and an average value thereof was obtained as the shape factor SF1.

(Manufacture of toner for electrostatic charge development)

The method for producing the electrostatic charge developing toner of the present invention described above is not particularly limited. For example, a binder resin, a colorant, a release agent, and a charge control agent as necessary are kneaded, pulverized, and classified. The dry kneading method that changes the shape of the particles obtained by the kneading and pulverizing method by mechanical impact force or thermal energy can be applied, but it is formed by emulsion polymerization of the polymerizable resin monomer The wet dispersion method such as emulsion polymerization aggregation method in which the dispersion liquid is mixed with a dispersion liquid of a colorant, a release agent and, if necessary, a charge control agent, and then agglomerated and heat-fused to obtain toner particles. However, since the mechanical share is low, the composition of the mixed release agent is not easily broken, and a larger amount of the release agent can be contained than in the dry production method.
In addition, a manufacturing method may be performed in which the toner obtained by the above method is used as a core, and agglomerated particles are further adhered and heat-fused to give a core-shell structure.

A toner production method suitable for producing the toner of the present invention will be described in more detail.
The toner production method of the present invention emulsifies a resin fine particle dispersion in which at least a first resin fine particle having a volume average particle diameter of 1 μm or less is dispersed, a colorant particle dispersion in which colorant particles are dispersed, and a release agent. A first aggregating step of mixing the release agent particle dispersion obtained in this way to form core agglomerated particles containing the first resin fine particles, the colorant particles, and the release agent particles, and the core agglomeration. A second aggregating step for forming core / shell agglomerated particles by forming a shell layer containing second resin fine particles on the surface of the particles; and the core / shell agglomerated particles as the first resin fine particles or the second resin fine particles. At least a fusion and coalescence step of fusing and coalescing by heating above the glass transition temperature.

  By producing the toner using the above production method, the toner of the present invention can be easily obtained in which the release agent is well dispersed in the toner and the toner surface exposure is small.

  In the first aggregation step, first, a resin fine particle dispersion, a colorant particle dispersion, and a release agent particle dispersion are prepared. The resin fine particle dispersion is prepared by dispersing the first resin fine particles prepared by emulsion polymerization or the like in a solvent using an ionic surfactant. Alternatively, the resin is dissolved in a soluble solvent and adjusted by phase inversion emulsification. The colorant particle dispersion is prepared by changing the colorant particles of a desired color such as black, blue, red, yellow using the ionic surfactant opposite to the ionic surfactant used in the preparation of the resin fine particle dispersion. It adjusts by making it disperse | distribute in a solvent.

  In addition, the release agent particle dispersion allows the release agent to be dispersed in water together with a polymer electrolyte such as an ionic surfactant, a polymer acid, or a polymer base, heated above the melting point, and subjected to strong shearing. It adjusts by atomizing with an apparatus.

As a device for fine dispersion by the above mechanical means, Menton Gorin high-pressure homogenizer (Gorin), continuous ultrasonic homogenizer (Nippon Seiki Co., Ltd.), Nanomizer (Nanomizer), Microfluidizer (Mizuho Industrial Co., Ltd.) Company), Harrell type homogenizer, Slasher (Mitsui Mining Co., Ltd.), Cavitron (Eurotech Co., Ltd.) and the like.

  Next, the resin fine particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mechanically mixed. At this time, an inorganic metal salt is added to release the first resin fine particles, the colorant particles, and the mold. The agglomerated particles (core agglomerated particles) including the first resin fine particles, the colorant particles, and the release agent composite particles having a diameter substantially close to a desired toner diameter are formed by heteroaggregating the agent particles. In this case, a plurality of types of resin fine particle dispersions may be prepared and used for adjusting the toner characteristics.

  In the second aggregating step, the second resin fine particles are adhered to the surface of the core agglomerated particles obtained in the first aggregating step using a resin fine particle dispersion containing the second resin fine particles, and a desired thickness is obtained. By forming the coating layer (shell layer), aggregated particles (core / shell aggregated particles) having a core / shell structure in which a shell layer is formed on the surface of the core aggregated particles are obtained. The second resin fine particles used at this time may be the same as or different from the first resin fine particles.

  Further, the particle diameters of the first resin fine particles, the second resin fine particles, the colorant particles, and the release agent particles used in the first and second aggregating steps are adjusted to desired values for the toner diameter and the particle size distribution. In order to facilitate this, it is preferably 1 μm or less, and more preferably in the range of 100 to 300 nm.

In the first aggregation step, the balance of the amounts of the two polar ionic surfactants (dispersants) contained in the resin fine particle dispersion and the colorant particle dispersion can be shifted in advance. For example, an inorganic metal salt such as calcium nitrate or a polymer of an inorganic metal salt such as polyaluminum chloride is ionically neutralized and heated below the glass transition temperature of the first resin fine particles to agglomerate the core. Particles can be made.

  In such a case, in the second flocculation step, the resin fine particle dispersion treated with the polar and amount dispersing agent that compensates for the deviation in the balance between the two polar dispersing agents as described above is used for the core flocculation. A core / shell aggregated particle is prepared by adding to a solution containing the particles and further heating slightly below the glass transition temperature of the core aggregated particle or the second resin fine particle used in the second aggregation step as necessary. be able to. In addition, the 1st and 2nd aggregation process may be repeatedly performed in multiple steps stepwise.

  Next, in the fusion / unification step, the core / shell aggregated particles obtained through the second aggregation step are used as a first or second resin fine particle contained in the core / shell aggregated particles in a solution. The toner is obtained by heating to above the glass transition temperature (if the resin type is two or more, the glass transition temperature of the resin having the highest glass point transition temperature), fusing and coalescence.

  After completion of the fusion / unification process, the toner formed in the solution is dried through a known washing process, solid-liquid separation process, and drying process to obtain a toner.

  In addition, it is preferable that the washing | cleaning process performs substitution washing | cleaning by ion-exchange water fully from a charging point. The solid-liquid separation step is not particularly limited, but suction filtration, pressure filtration, and the like are preferably used from the viewpoint of productivity. Further, although the drying process is not particularly limited, freeze drying, flash jet drying, fluidized drying, vibration fluidized drying and the like are preferably used from the viewpoint of productivity.

(Toner production conditions)
In the electrostatic charge developing toner of the present invention, as described above, a low specific gravity of A × 0.95 or less with respect to the average specific gravity (A) of the electrostatic charge developing toner in the electrostatic charge developing toner. The toner content (B) satisfies the following formula (1).
0.1% by mass ≦ B ≦ 1.5% by mass (1)

  The content of the low specific gravity toner having an average specific gravity (A) of 0.95 or less with respect to the total amount of the electrostatic charge developing toner varies depending on the toner production conditions. In order to adjust the content of the low specific gravity toner of the average specific gravity × 0.95 or less with respect to the average specific gravity of the electrostatic charge developing toner to be within the range represented by the above formula (1), Manufacturing conditions are mentioned.

In the first agglomeration step, the inorganic fine metal salt is gradually added and ionically neutralized while mechanically mixing the resin fine particle dispersion, the colorant particle dispersion, and the release agent particle dispersion, thereby aggregating the particles. Form a collection. The specific gravity distribution of the final toner changes depending on the dispersion conditions at this time.
For example, the resin fine particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are squeezed into a 3 L stainless steel kettle at a desired ratio so that the total solid content becomes 150 g, and the total solid content becomes 13%. Adjust by adding ion-exchanged water so that The inorganic metal salt is gradually added while stirring with IKA Ultra Tarrax T50 to form aggregates of each particle. At this time, the dispersion and aggregation properties change depending on the rotation speed and time of stirring, and the final toner The specific gravity distribution changes.
If the rotational speed is too low, the content (B) of the low specific gravity toner of A × 0.95 or less with respect to the average specific gravity (A) of the toner increases, and increases even if the stirring time is short. It is necessary to set the number of revolutions and time.
10000 (rpm / min) ≤ rotation speed x dispersion time ≤ 100000 (rpm / min)
It is necessary to satisfy. Below 10,000 (rpm · min), the content (B) of the low specific gravity toner exceeds the predetermined amount, and when it exceeds 100,000 (rpm · min), the aggregate is redispersed due to excessive dispersion share, and again the low specific gravity is low. The toner content (B) is larger than a predetermined amount.
As another method, there is a method of preparing the aforementioned potassium iodide (specific gravity 3.3) solution and adjusting the content (B) of the low specific gravity toner before washing.
The solution after the completion of the fusion / unification process is put into a potassium iodide solution, sufficiently stirred mechanically, and left for 24 hours. In this case, the specific gravity of the aqueous potassium iodide solution is calculated by taking into account the amount of water (measured separately) in the solution. After the average specific gravity (A) of the toner is obtained from the floating amount with respect to the solution of each specific gravity, the solution is added to the average specific gravity (A) of the toner, and the average specific gravity (A) of the toner becomes 0.95. Put the cake in the potassium halide solution, measure the floating amount after standing for 24 hours, and remove the floating toner so that the content (B) of the low specific gravity toner is in the range of 0.1 mass% to 1.5 mass%. except. Thereafter, the toner in a dried state is obtained through a washing step and a solid-liquid separation step.
In the case of using this step, it is necessary to keep the stirring rotation speed and time of the ultra turrax T50 at a certain level or lower as the dispersion conditions in the first aggregation step. Specifically, it is less than 10000 (rpm · min).

<Developer>
The electrostatic charge developing toner of the present invention obtained as described above may be used as a one-component developer as it is, but in the present invention, it is used as a toner in a two-component developer comprising a carrier and a toner. Is preferred.
The carrier that can be used for the two-component developer is preferably formed by coating the surface of the core material with a resin. The core material of the carrier is not particularly defined as long as the above conditions are satisfied, for example, magnetic metals such as iron, steel, nickel, cobalt, alloys of these with manganese, chromium, rare earth, ferrite, magnetite, etc. From the viewpoint of the surface property of the core material and the resistance of the core material, ferrite, particularly an alloy with manganese, lithium, strontium, magnesium or the like is preferable.

  The resin covering the surface of the core material is not particularly limited as long as it can be used as a matrix resin, and can be appropriately selected according to the purpose. For example, polyolefin resins such as polyethylene and polypropylene; polyvinyl resins and polyvinylidene resins such as polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone Vinyl chloride-vinyl acetate copolymer; styrene-acrylic acid copolymer; straight silicone resin composed of organosiloxane bond or modified product thereof; polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, polychlorotrifluoroethylene, etc. Fluorine resin; Silicone resin; Polyester; Polyurethane; Polycarbonate; Phenol resin; Urea-formaldehyde resin, Melamine tree , Benzoguanamine resins, urea resins, amino resins such as polyamide resins, epoxy resins, per se known resins and the like. These may be used individually by 1 type and may use 2 or more types together. In the present invention, among these resins, it is preferable to use at least a fluororesin and / or a silicone resin. The use of at least a fluorine-based resin and / or a silicone resin as the resin is advantageous in that it has a high effect of preventing carrier contamination (impact) due to toner and external additives.

  The film made of the resin is formed by dispersing at least resin particles and / or conductive particles in the resin. Examples of the resin particles include thermoplastic resin particles and thermosetting resin particles. Among these, thermosetting resins are preferable from the viewpoint of relatively easily increasing the hardness, and resin particles made of nitrogen-containing resin containing N atoms are preferable from the viewpoint of imparting negative chargeability to the toner. In addition, these resin particles may be used individually by 1 type, and may use 2 or more types together. The average particle size of the resin particles is preferably about 0.1 to 2 μm, more preferably 0.2 to 1 μm. When the average particle size of the resin particles is less than 0.1 μm, the resin particles are not highly dispersible in the coating. On the other hand, when the average particle size exceeds 2 μm, the resin particles easily fall off from the coating, and the original effect is exhibited. It may disappear.

Examples of the conductive particles include metal particles such as gold, silver and copper, carbon black particles, semiconductive oxide particles such as titanium oxide and zinc oxide, titanium oxide, zinc oxide, barium sulfate, aluminum borate, and titanic acid. Examples thereof include particles in which the surface of potassium powder or the like is covered with tin oxide, carbon black, metal, or the like. These may be used individually by 1 type and may use 2 or more types together. Among these, carbon black particles are preferable from the viewpoints of production stability, cost, conductivity, and the like. The type of carbon black is not particularly limited, but carbon black having a DBP oil absorption of about 50 to 250 ml / 100 g is preferable because of excellent production stability.

  The method of coating the resin on the surface of the carrier core material is not particularly limited. For example, the resin particles such as crosslinkable resin particles and / or the conductive particles, and a styrene acrylic resin or fluorine as a matrix resin. And a method of using a film-forming liquid containing a resin such as a resin based on silicone or a silicone resin in a solvent.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the film forming liquid, a spray method in which the film forming liquid is sprayed on the surface of the carrier core material, and the carrier core material in flowing air. For example, a kneader coater method may be used in which the film-forming liquid is mixed in a suspended state by removing the solvent. Among these, the kneader coater method is preferable in the present invention.

The solvent used in the film-forming liquid is not particularly limited as long as it can dissolve only the resin as a matrix resin, and can be selected from among solvents known per se, for example, Aromatic hydrocarbons such as toluene and xylene, ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran and dioxane, and the like. When the resin particles are dispersed in the coating, since the resin particles and the particles as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface, the carrier is used for a long time. Even when the coating is worn, it is possible to always maintain the same surface formation as when it is not used, and to maintain a good charge imparting ability for the toner over a long period of time. In the case where the conductive particles are dispersed in the coating, the conductive particles and the resin as the matrix resin are uniformly dispersed in the thickness direction and the tangential direction of the carrier surface. Even when the coating is worn out for a long period of time, the same surface formation as when not in use can be maintained, and carrier deterioration can be prevented for a long period of time. In addition, when the said resin particle and the said electroconductive particle are disperse | distributed to the said film, there can exist the above-mentioned effect simultaneously.

  The mixing ratio (mass ratio) of the electrostatic image developing toner of the present invention and the carrier in the two-component developer is preferably in the range of toner: carrier = 1: 100 to 30: 100, and 3: 100. The range of about 20: 100 is more preferable.

(Image forming method)
The image forming method of the present invention includes at least an electrostatic latent image forming step of forming an electrostatic latent image on a precharged image carrier, developing the electrostatic latent image with a developer containing toner, A developing step for forming a toner image on the image carrier, a transfer step for transferring the toner image formed on the image carrier onto the transfer member, and a transfer of the toner image onto the transfer member. An image forming method comprising: a cleaning step for removing the toner remaining on the image carrier later from the image carrier; and a fixing step for fixing the toner image transferred onto the transfer body. The toner is the electrostatic charge developing toner of the present invention.

  The electrostatic latent image forming step is a step of forming an electrostatic latent image by exposing an image carrier having a uniformly charged surface with an exposure means such as a laser optical system or an LED array. The image forming method of the present invention is not subject to any particular limitation in the exposure method.

  For charging the image carrier, a non-contact charger such as corotron or scorotron, and a contact type charger that charges the image carrier surface by applying a voltage to a conductive member in contact with the image carrier surface. A charger is used, and any type of charger may be used. However, it is preferable to use a contact charging type charger from the viewpoint that the amount of ozone generated is small, environmentally friendly, and excellent printing durability. In the contact charging type charger, the shape of the conductive member may be any of a brush shape, a blade shape, a pin electrode shape, a roll shape, and the like, but a roll-like member is preferable. The image forming method of the present invention is not subject to any particular limitation in the charging method.

  The development process refers to the developer carrier having a developer layer containing at least toner formed on the surface of the image carrier, in contact with or in close proximity to the toner particles attached to the electrostatic latent image on the surface of the image carrier. And a toner image is formed on the surface of the image carrier. The development method can be performed using a known method, but examples of the development method using a two-component developer include a cascade method and a magnetic brush method.

  In the case of the magnetic brush method, a magnetic sleeve is used as a developer carrier. A known material such as material and magnetic force can be used for the magnetic sleeve, but the irregularities on the sleeve surface have a ten-point average roughness Rz in the range of 15 to 25 μm and a center line average roughness Ra in the range of 1 to 5 μm. By using fine irregularities, it is possible to ensure developer transport stability, suppress carrier scattering, and form a good image without defects. In general, sleeves generally used have an Rz of 10 μm or less, but a carrier having a small diameter, a carrier having a small shape factor SF1 (the shape factor SF1 being smaller than 125), a toner having a small diameter, and a shape factor SF1. When using any of the small toners (having a shape factor SF1 smaller than 140), or when using them in combination, the transport of the developer tends to become unstable, so when using these developers The use of the above-described magnetic sleeve is effective for maximizing the characteristics of the developer. The image forming method of the present invention is not particularly limited with respect to the developing method.

The transfer process is a process of forming a transfer image by transferring a toner image formed on the surface of the image carrier to a transfer target such as a recording medium. In the case of full-color image formation, it is preferable that the respective color toners are primarily transferred to an intermediate transfer drum or belt as an intermediate transfer member and then secondarily transferred to a recording medium such as paper. Further, from the viewpoint of versatility of the paper and high image quality, it is preferable to transfer the color toner images of the respective colors onto the intermediate transfer member and then transfer the color toner images of the respective colors onto the recording medium at a time.
In the present invention, when a toner image is directly transferred from an image carrier to a recording medium or the like, the recording medium becomes a transfer medium. However, when an intermediate transfer body is used for forming a full-color image. The intermediate transfer member is also included in the transfer target.

  A corotron can be used as a transfer device for transferring a toner image from the image carrier to paper or an intermediate transfer member. The corotron is effective as a means for uniformly charging the paper, but in order to give a predetermined charge to the paper as a recording medium, a high voltage of several kV must be applied and a high voltage power source is required. In addition, ozone is generated by corona discharge, which causes deterioration of rubber parts and the image carrier. Therefore, contact transfer that transfers a toner image onto a sheet by pressing a conductive transfer roll made of an elastic material against the image carrier. It is preferable to use a method. In the image forming method of the present invention, the transfer device is not particularly limited.

  The fixing step is a step of fixing the toner image transferred on the surface of the recording medium with a fixing device. As the fixing device, a heat fixing device using a heat roll is preferably used. As the heat fixing device, for example, a fixing roll provided with a heater lamp for heating inside a cylindrical metal core, and a so-called release layer formed on the outer peripheral surface by a heat resistant resin film layer or a heat resistant rubber film layer; The pressure roll or the pressure belt is disposed in pressure contact with the fixing roll and has a heat-resistant elastic body layer formed on the outer peripheral surface of the cylindrical metal core or the surface of the belt-like base material. The fixing process of an unfixed toner image is performed by inserting a recording medium on which an unfixed toner image is formed between a fixing roll and a pressure roll or a pressure belt, and heating the binder resin, additives, etc. in the toner. Fix by melting.

  Here, as the fixing roll, for example, a fixing belt having a low surface energy material typified by a fluororesin component and a silicon resin on the surface and having a belt shape, similarly, a fluororesin component and a silicon resin on the surface And those having a low surface energy material typified by and having a cylindrical roll shape. Furthermore, a metal roll can be used as the fixing roll. Compared to a metal roll that has a low surface energy material such as a fluororesin or silicon resin on the surface of a member that comes into contact with the toner image, such as a general fixing roll. Greatly improved.

  Further, a general fixing roll needs to introduce a filler and harden a release layer in order to maintain strength against a fixing roll contact type release auxiliary mechanism represented by a peeling claw. Furthermore, in order to suppress electrostatic offset due to the fixing roll resistance, it is necessary to disperse the conductive material in the release layer.

  On the other hand, since a metal roll has hardness and conductivity in the roll itself, it is not necessary to reinforce strength or impart conductivity. This indicates that there is no need for complicated repeating steps such as coating, drying, and polishing over a number of layers as in the case of a general fixing roll. From the viewpoint of environmental impact, as described above, it is possible to reduce the environmental impact by reducing manufacturing energy by simplifying the process, and disposal is not performed because low surface energy materials typified by fluororesin and silicon resin are not used. Fluoride and the like are not generated. Further, it is not necessary to separate the fixing roll and the release layer, and the disposal process can be simplified. Moreover, since it is a metal from the viewpoint of recycling and reuse, at least material recycling is possible. Moreover, it can be reused again as a fixing roll if it is given some surface cleaning / polishing.

  The fixing roll has a surface roughness Ra of 0.01 to 5.0 μm, which is in direct contact with the unfixed toner image surface. The fixing roll of the present invention is required to have a surface roughness Ra in the range of 0.01 to 5.0 μm, and more preferably in the range of 0.10 to 4.0 μm. When the surface roughness Ra of the fixing roll is less than 0.01 μm, there is a problem that high-temperature offset occurs although it is superior with respect to melting unevenness and gloss on the fixed image surface.

  In general, the offset phenomenon is roughly classified into what is called a high temperature offset and what is called a low temperature offset. A high temperature offset is caused by adhesion of molten toner to a heat fixing roll, and a low temperature offset is caused by unmelted toner particles. This is due to adhesion to the heat fixing roll, and is determined by the surface temperature distribution state of the heat fixing roll, the contact area with the toner image surface, the toner characteristics, and the like.

  When the fixing roll surface roughness Ra is less than 0.01 μm, the following may be considered as the cause of the high temperature offset. One is that when the fixing agent is interposed between the fixing roll surface and the toner image surface at the time of fixing, the fixing roller surface is a mirror surface, so that the releasing agent cannot sufficiently exist on the toner image surface and a high temperature offset occurs. Can be estimated. This is presumably because the surface of the fixing roll is not rough, so that the release agent cannot be held on the fixing roll and the release agent does not function sufficiently. On the other hand, regarding the releasability of the toner image, it can be estimated that a high temperature offset has occurred due to an increase in contact area and contact state between the fixing roll surface and the toner image surface. This is because, when fixing rolls with different roughness are considered, the contact area between the fixing roll surface and the toner image surface is smoother and the contact area per unit area is larger or the individual contact areas are the same. Since the contact surface is large, it can be presumed that the peeling force becomes large, which is disadvantageous for peeling and causes high temperature offset.

  When the surface roughness Ra of the fixing roll is larger than 5.0 μm, the releasing agent holding ability and the contact area / contact state work advantageously with respect to the high temperature offset for the reasons described above. However, problems occur in terms of roughness of the fixed image surface and gloss, and when a color toner is laminated and fixed in two or more colors, a uniform image surface cannot be obtained with respect to gloss and color development.

  With regard to this surface roughness, a general fixing roll coated with a low surface energy material typified by a fluorine resin or a silicon resin can be expected to have the same effect if the surface roughness is defined. It can be said that the metal roll is more excellent from the viewpoint of maintainability and the manufacturing process.

  Here, regarding the production of the metal roll, the material of the metal roll is not particularly limited as long as it is a material having excellent mechanical strength and good thermal conductivity. For example, aluminum, SUS, iron, Examples include metals and alloys such as copper and brass. The processing method of the fixing roll surface roughness Ra is not particularly limited, but general surface processing methods such as cutting and blast polishing can be used.

  The fixing speed in the fixing step (hereinafter referred to as process speed) is preferably in the range of 150 to 400 mm / s, more preferably in the range of 200 to 350 mm / s. When the process speed is slower than 100 mm / s, when a metal roll is used, high temperature offset tends to occur due to high heat conduction. On the other hand, when the process speed exceeds 400 mm / s, the heat transfer is reduced, and the surface of the fixed image becomes rough, and defects such as peeling claws occur.

  In the image forming method of the present invention, the fixing method is not particularly limited.

  The cleaning step is a step of removing residual toner remaining as a transfer residue on the surface of the image carrier after the transfer step. As cleaning means, a blade cleaning system or a system using an electrostatic brush is known.

  As the electrostatic brush, a resin containing a conductive filler such as carbon black or a metal oxide or a fibrous substance (conductive brush) coated on the surface can be used, but the invention is not limited thereto. As a cleaning method using an electrostatic brush, a voltage can be applied to the electrostatic brush.

  In the image forming method of the present invention, since the electrostatic charge developing toner is used such that the content of the low specific gravity toner with respect to the total amount of the electrostatic charge developing toner satisfies the range of the above formula (1), The friction coefficient between the image carrier and the blade or the image carrier and the electrostatic brush due to the coating amount (filming) of the release agent being too small increases the wear and chipping of the blade and the electrostatic brush. Inability to withstand long-term use can be suppressed. Further, since the amount of the release agent coating (filming) on the surface of the image bearing member is too large, it is possible to suppress image quality deterioration due to toner adhesion and deposition on the release agent coated. Accordingly, it is possible to provide a toner for developing an electrostatic charge that is stable for long-term use and an image forming method using the toner.

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

  The toner of the present invention can be obtained by the following method. That is, the following resin fine particles, colorant particle dispersion, release agent particle dispersion, and inorganic fine particle dispersion are prepared.

  Next, while a predetermined amount of these are mixed and stirred, a polymer of an inorganic metal salt is added thereto and ionically neutralized to form aggregates of the above particles. Before the desired toner particle diameter is reached, resin fine particles are additionally added to obtain the toner particle diameter. Next, after adjusting the pH of the system from a weakly acidic to a neutral range with an inorganic hydroxide, the mixture is heated to a temperature higher than the glass transition temperature of the resin fine particles, and united and fused. After completion of the reaction, a desired toner is obtained through sufficient washing, solid-liquid separation, and drying processes.

  Examples of how to prepare each material and how to create aggregated particles will be described below.

<Measurement method>
In the production of each of the following materials, each measurement was performed by the following method.
-Measurement of toner shape factor SF1-
The toner shape factor SF1 is obtained by taking an optical microscope image of toner dispersed on a slide glass into a Luzex image analyzer through a video camera, and calculating the square of the maximum length of 50 toners / projection area (ML ² / A) × 100. It is obtained by calculating and obtaining an average value.

-Toner particle size and particle size distribution measurement method-
In the present invention, the toner particle size and particle size distribution were measured using a Coulter Counter TA-II type (manufactured by Beckman-Coulter) as the measuring device, and ISOTON-II (manufactured by Beckman-Coulter) as the electrolyte.

  As a measurement method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. This was added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 to 60 μm is measured using the Coulter counter TA-II type with an aperture diameter of 100 μm. The volume average particle diameter, GSDv, and GSDp were determined as described above. The number of particles to be measured was 50,000.

-Volume average particle size of fine particles-
The volume average particle diameter was measured with a laser scattering diffraction particle size distribution analyzer (LS 13 320, manufactured by Beckman-Coulter).

-Measurement method of melting point, glass transition temperature and endotherm of resin and toner-
The melting point of the toner of the present invention, the crystalline polyester resin, and the glass transition temperature of the toner and the amorphous resin are as shown in FIG. 1 according to ASTM D3418-8 (crystalline polyester resin, amorphous resin). Was obtained from each maximum peak measured in the first temperature rise only). The glass transition point was the temperature at the intersection of the extension line of the base line and the rising line in the endothermic part, and the melting point was the temperature at the apex of the endothermic peak.

Further, the endothermic amounts ΔH1 and ΔH2 were obtained from the peak area of the endothermic peak portion with respect to the baseline in the first and second temperature rising processes described above.
A differential scanning calorimeter (manufactured by Shimadzu Corporation, DSC-50) was used for the measurement.

<Toner preparation>
-Preparation of crystalline polyester resin dispersion (A)-

  In a heat-dried three-necked flask, 98 mol% 1,10-dodecanedioic acid, 2 mol% dimethyl-5-sulfonate sodium, 100 mol% 1,9-nonanediol, and 0.3 parts by mass of dibutyltin oxide as a catalyst After that, the air in the container was made into an inert atmosphere with nitrogen gas by depressurization, and the mixture was stirred and refluxed at 180 ° C. for 5 hours by mechanical stirring.

Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 4 hours. When it became viscous, it was air-cooled to stop the reaction, and a crystalline polyester resin (A) was synthesized. As a result of molecular weight measurement (polystyrene conversion) by gel permeation chromatography, the obtained crystalline polyester resin (A) had a mass average molecular weight (Mw) of 15,500.

Further, when the melting point (Tm) of the crystalline polyester resin (A) was measured by the above-described measurement method using a differential scanning calorimeter (DSC), it showed a clear endothermic peak, and the endothermic peak temperature was 75 ° C. there were. The specific gravity of the crystalline polyester resin (A) was 1.15.

-Adjustment of resin fine particle dispersion-
Using the crystalline polyester resin (A), a resin fine particle dispersion was prepared.
・ Crystalline polyester resin (A) 90 mass ・ Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.) 1.8 mass parts ・ Ion-exchanged water 210 mass parts or more heated to 100 ° C. After sufficiently dispersing, the mixture was heated to 110 ° C. with a pressure discharge type gorin homogenizer and dispersed for 1 hour to obtain a resin fine particle dispersion having a volume average particle size of 270 nm and a solid content of 30%.

-Preparation of amorphous polymer resin dispersion (B)-
・ Terephthalic acid: 40mol%
・ Fumaric acid: 60mol%
・ Bisphenol A ethylene oxide 2 mol adduct 20 mol%
・ Bisphenol A propylene oxide adduct 80mol%
The above monomer is charged into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectifying column, and the temperature is raised to 190 ° C. over 1 hour, and the reaction system is uniformly stirred. After confirming the above, 1.2 parts by mass of dibutyltin oxide was added. Furthermore, while distilling off the generated water, it took 6 hours from the same temperature to raise the temperature to 240 ° C, and continued the dehydration condensation reaction at 240 ° C for another 3 hours, with a glass transition point of 61 ° C and an acid value of 8.0 mg. Amorphous polyester resin (B) having a weight average molecular weight of 12,500 was obtained. The specific gravity of the amorphous polyester resin (B) was 1.18.

-Preparation of amorphous polymer resin dispersion liquid consisting of amorphous polyester resin (B)-
The amorphous polyester resin (B) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. In a separately prepared aqueous medium tank, 0.37% by mass diluted aqueous ammonia diluted with reagent-exchanged ammonia water with ion-exchanged water is added and heated to 120 ° C. with a heat exchanger at a rate of 0.1 liter / min. The polyester resin (B) melt was transferred to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.).

Amorphous polymer resin dispersion consisting of amorphous polyester resin (B) with volume average particle size of 0.16μm and solid content of 30%, operating Cavitron under conditions of rotor rotation speed 60Hz and pressure 5kg / cm ² A liquid was obtained.

-Preparation of amorphous polymer resin dispersion (C)-
・ Terephthalic acid: 80mol%
・ Isophthalic acid: 20mol%
・ Bisphenol A ethylene oxide 2-mol adduct 50 mol%
・ Cyclohexanedimethanol 50mol%
The above monomer is charged into a 5 liter flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectifying column, and the temperature is raised to 190 ° C. over 1 hour, and the reaction system is uniformly stirred. After confirming the above, 1.2 parts by mass of dibutyltin oxide was added. Furthermore, while distilling off the generated water, it took 6 hours from the same temperature to raise the temperature to 240 ° C, and continued the dehydration condensation reaction at 240 ° C for another 4 hours, with a glass transition point of 63 ° C and an acid value of 8.5 mg. Amorphous polyester resin (C) having a weight average molecular weight of 13,000 was obtained. The specific gravity of the amorphous polyester resin (C) was 1.22.

-Amorphous polymer resin dispersion consisting of amorphous polyester resin (C)-
The amorphous polyester resin (C) was transferred in a molten state to Cavitron CD1010 (manufactured by Eurotech Co., Ltd.) at a rate of 100 g / min. In a separately prepared aqueous medium tank, 0.37% by mass diluted aqueous ammonia diluted with reagent-exchanged ammonia water with ion-exchanged water is added and heated to 120 ° C. with a heat exchanger at a rate of 0.1 liter / min. The polyester resin (C) melt was transferred to Cavitron CD1010 (Eurotech Co., Ltd.).

Amorphous polymer resin dispersion consisting of amorphous polyester resin (C) with a mean particle size of 0.20μm and a solid content of 30%, operating the Cavitron under the conditions of a rotor speed of 60 Hz and a pressure of 5 kg / cm ² Got.

-Preparation of amorphous polymer resin (D) dispersion-
・ Styrene 370 parts by mass ・ N-butyl acrylate 30 parts by mass ・ Acrylic acid 4 parts by mass ・ Dodecanethiol 24 parts by mass ・ Carbon tetrabromide 4 parts by mass In a flask, 6 parts by mass of Kasei Co., Ltd .: Nonipol 400) and 10 parts by mass of an anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd .: Neogen SC) were dissolved in 560 parts by mass of ion-exchanged water. Disperse, emulsify, slowly mix for 10 minutes, add 50 parts by mass of ion-exchanged water in which 4 parts by mass of ammonium persulfate is dissolved, and after replacing with nitrogen, stir the contents in the flask. The mixture was heated in an oil bath until the temperature reached 70 ° C., and the emulsion polymerization was continued for 5 hours. Thus, an amorphous polymer dispersion in which resin particles having a volume average particle size of 180 nm, a glass transition point of 55 ° C., a weight average molecular weight (Mw) of 15800, and a specific gravity of 1.18 are dispersed (resin particle concentration: 30%) Was prepared.

-Preparation of colorant particle dispersion 2-
・ Blue pigment (copper phthalocyanine B15: 3: manufactured by Dainichi Seika) 50 parts by mass ・ Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku) 5 parts by mass ・ Ion-exchanged water 195 parts by mass After dispersion for 10 minutes by IKA Ultra Tarrax), dispersion treatment is performed for 15 minutes at a pressure of 245 Mpa using an optimizer (counter-impact collision type wet pulverizer: Sugino Machine), the colorant particles have a center particle size of 462 nm and a solid content 20.0% of colorant particle dispersion 2 was obtained.

-Preparation of release agent particle dispersion 1-
・ Olefin wax (melting point: 85 ° C., specific gravity: 0.92) 90 parts by mass ・ Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku) 1.8 parts by mass ・ Ion-exchanged water 210 parts by mass After fully dispersing with IKA Ultra Turrax T50, heat it to 110 ° C with a pressure discharge type gorin homogenizer and perform dispersion treatment for 1 hour to obtain a release agent particle dispersion 1 with a center diameter of 200nm and a solid content of 30%. Obtained.

-Preparation of release agent particle dispersion 2-
-Synthetic ester wax (melting point: 75 ° C, specific gravity: 0.95) 90 parts by mass-Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku) 1.8 parts by mass-210 parts by mass of ion-exchanged water , Fully dispersed with IKA Ultra Turrax T50, heated to 110 ° C with a pressure discharge type gorin homogenizer, and dispersed for 1 hour. Dispersant dispersion 2 with a center diameter of 230 nm and a solid content of 30% Got.

―Preparation of Toner 1―
-Amorphous polymer resin dispersion (B) 166 parts by mass-Crystalline polyester resin dispersion (A) 50 parts by weight-Colorant particle dispersion 2 20 parts by weight-Release agent particle dispersion 1 40 parts by weight In a round stainless steel flask, the mixture was thoroughly mixed and dispersed with IKA Ultra Turrax T50. Next, 0.20 part by mass of polyaluminum chloride was added thereto, and the dispersion operation was continued for 10 minutes (= 60000 rpm · min) at a rotation speed of 6000 rpm with an ultra turrax. The flask was heated to 48 ° C. with stirring in an oil bath for heating. After maintaining at 48 ° C. for 60 minutes, 60 parts by mass of the amorphous polymer resin (C) dispersion was gradually added thereto.

Thereafter, the pH of the system was adjusted to 9.0 with a 0.5 mol / l aqueous sodium hydroxide solution, the stainless steel flask was sealed, heated to 96 ° C. while continuing stirring using a magnetic seal, and maintained for 5 hours.
After completion of the reaction, the mixture was cooled, filtered, sufficiently washed with ion exchange water, and then subjected to solid-liquid separation by Nutsche suction filtration. This was further redispersed in 1 L of ion exchange water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes.
This was repeated five more times, and when the filtrate had a pH of 7.5 and an electric conductivity of 7.0 μS / cmt, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. Then, vacuum drying was continued for 12 hours to obtain toner 1.

  When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 5.9 microns, the particle size distribution coefficient GSD was 1.20, and (GSDv / GSDp) was 0.96. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 129, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of low specific gravity toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 0.3% by mass.

―Preparation of Toner 2―
Dispersion operation of IKA Ultra Tarrax T50 after adding 0.20 parts by weight of polyaluminum chloride: Preparation of Toner 1 except that 10 minutes at 6000 rpm and 2 minutes at 4000 rpm (= 8000 rpm) A toner was prepared in the same manner as described above to obtain toner 2.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 6.1 microns, the particle size distribution coefficient GSD was 1.25, and (GSDv / GSDp) was 0.97. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 130, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of the low specific gravity toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 1.7% by mass.

―Preparation of Toner 3―
Dispersion operation of IKA Ultra Tarrax T50 after adding 0.20 parts by mass of polyaluminum chloride: Preparation of Toner 1 except that 10 minutes at 6000 rpm and 5 minutes at 5000 rpm (= 25000 rpm) A toner was prepared in the same manner as described above to obtain toner 3.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 6.1 microns, the particle size distribution coefficient GSD was 1.26, and (GSDv / GSDp) was 0.96. Further, the shape factor SF1 of the particles determined by shape observation with Luzex was 128, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of the low specific gravity toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 1.4% by mass.

―Preparation of Toner 4―

Dispersion operation of IKA Ultra Tarrax T50 after adding 0.20 parts by mass of polyaluminum chloride: Preparation of Toner 1 except for 10 minutes at 6000 rpm and 5 minutes at 6000 rpm (= 30000 rpm · min) A toner was prepared in the same manner as described above to obtain toner 4.
The particle diameter at this time was measured with a Coulter counter. The volume average diameter D50 was 6.5 microns, the particle size distribution coefficient GSD was 126, and (GSDv / GSDp) was 0.96. In addition, the particle shape factor SF1 obtained by shape observation with Luzex was 115, which was observed to be a potato shape close to a sphere. A specific gravity distribution measurement was performed, and the amount of low specific gravity toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 0.7% by mass.

―Preparation of Toner 5―
Before the Nutsche suction filtration in the preparation of the toner 1, the toner dispersion is put into the potassium iodide solution so that it finally becomes a potassium iodide solution having a specific gravity of 1.15, and the toner is left floating for 24 hours. A toner was prepared in the same manner as in the preparation of the toner 1 except that the toner was separated together with the solution.
The particle diameter at this time was measured with a Coulter counter. The volume average diameter D50 was 6.2 microns, the particle size distribution coefficient GSD was 1.28, and (GSDv / GSDp) was 0.95. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 126, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of low specific gravity toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 0.05% by mass.

―Preparation of Toner 7―
Similar to the preparation of toner 1 except that the amorphous polymer resin dispersion (B) was changed to the amorphous polymer resin dispersion (D), and the release agent particle dispersion 2 was changed to the release agent particle dispersion 1. Toner was prepared and Toner 7 was obtained.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 6.5 microns, the particle size distribution coefficient GSD was 1.30, and (GSDv / GSDp) was 0.96. In addition, the particle shape factor SF1 obtained by shape observation with Luzex was 128.5, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of low specific gravity toner having an average specific gravity of 1.15 and an average specific gravity of 0.95 or less was 0.2% by mass.

―Preparation of Toner 8―
Before making Nutsche suction filtration in the preparation of Toner 2, the toner dispersion is put into the potassium iodide solution so that it finally becomes a potassium iodide solution having a specific gravity of 1.11, and the toner is left floating for 24 hours. A toner was prepared in the same manner as in the preparation of the toner 2 except that half of the solution was separated from the solution.
When the particle diameter at this time was measured with a Coulter counter, the volume average particle diameter D50 was 6.1 microns, the particle size distribution coefficient GSD was 1.26, and (GSDv / GSDp) was 0.96. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 126, and it was observed that the particles were potato-like. The specific gravity distribution was measured, and the amount of low specific toner having an average specific gravity of 1.17 and an average specific gravity of 0.95 or less was 0.8% by mass.

<Creation of carrier>
Ferrite particles (EFC50B, manufactured by Powdertech, volume average particle size 50 μm): 100 parts by mass Toluene: 14 parts by mass Perfluorooctylethyl acrylate / methyl methacrylate copolymer (copolymerization ratio 40:60 Mw = 50,000) 1.6 parts by mass Carbon black (VXC-72; manufactured by Cabot) 0.12 parts by mass Crosslinked melamine resin particles (number average particle size: 0.3 μm) ..0.3 parts by mass

  Among the above components, the components except for the ferrite particles are dispersed with a stirrer for 10 minutes to prepare a film forming liquid, and the film forming liquid and the ferrite particles are put into a vacuum degassing kneader and stirred at 60 ° C. for 30 minutes. After that, the pressure was reduced and toluene was distilled off, and a resin film was formed on the surface of the ferrite particles to produce a carrier.

Example 1
-Addition of external additives-
Using Henschel mixer, 100 parts by mass of toner of toner 1, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) are used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh size of 45 μm to obtain externally added toner 1.
-Production of developer-
Developer 1 was produced by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 1 at 40 rpm for 20 minutes using a V-blender and sieving with a sieve having a 177 μm mesh.

(Comparative Example 1)
-Addition of external additives-
Using Henschel mixer, 100 parts by mass of toner 2 of toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) with an average particle diameter of 30 nm are used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh of 45 μm to obtain an externally added toner 2.
-Production of developer-
Developer 2 was produced by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 2 at 40 rpm for 20 minutes using a V-blender and sieving with a sieve having a 177 μm mesh.

(Example 2)
-Addition of external additives-
Using a Henschel mixer, 100 parts by weight of toner 3 of toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 30 nm are used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh of 45 μm to obtain an externally added toner 3.
-Production of developer-
94 parts by mass of the carrier and 6 parts by mass of the externally added toner 3 were stirred at 40 rpm for 20 minutes using a V-blender, and sieved with a sieve having a 177 μm mesh to prepare Developer 3.

(Example 3)
-Addition of external additives-
Using a Henschel mixer, 100 parts by mass of toner 4 of toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh of 45 μm, and an externally added toner 4 was obtained.
-Production of developer-
Developer 4 was produced by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 4 at 40 rpm for 20 minutes using a V-blender, and sieving with a sieve having a 177 μm mesh.

(Comparative Example 2)
-Addition of external additives-
Using Henschel mixer, 100 parts by mass of toner 5 of toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) with an average particle diameter of 30 nm were used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh of 45 μm to obtain an externally added toner 5.
-Production of developer-
Developer 5 was prepared by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 5 with a V-blender at 40 rpm for 20 minutes and sieving with a sieve having a 177 μm mesh.

(Example 4 )
-Addition of external additives-
Using a Henschel mixer, 100 parts by mass of toner 7 toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) having an average particle diameter of 30 nm are used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh of 45 μm, and an externally added toner 7 was obtained.
-Production of developer-
Developer 7 was produced by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 7 at 40 rpm for 20 minutes using a V-blender and sieving with a sieve having a 177 μm mesh.

(Example 5 )
-Addition of external additives-
Using a Henschel mixer, 100 parts by mass of toner 8 of toner, 0.8 part of hydrophobic titania treated with decylsilane having an average particle diameter of 15 nm, and 1.3 parts of hydrophobic silica (NY50, manufactured by Nippon Aerosil Co., Ltd.) are used. After blending at a peripheral speed of 32 m / s * 10 minutes, coarse particles were removed using a sieve having a mesh size of 45 μm to obtain externally added toner 8.
-Production of developer-
Developer 8 was produced by stirring 94 parts by mass of carrier and 6 parts by mass of externally added toner 7 at 40 rpm for 20 minutes using a V-blender and sieving with a sieve having a 177 μm mesh.

[Image quality evaluation]
Using the commercially available electrophotographic copying machine (Docu Center Color 400 remodeled machine (manufactured by Fuji Xerox Co., Ltd., blade cleaning method)), 2000 000 images with a density of 5% were printed on each of the developers 1 to 8 above. Later, a visual sensory evaluation was performed by comparing a sample printed with 5 full-tone halftone images with a density of 20% and a full-scale halftone image with a density of 20% sampled initially. The evaluation results are shown in Table 1.
<Image quality evaluation criteria>
○: There is no image distortion and no black streaks compared to the initial halftone image.
X: There are white spots in the image compared to the initial halftone image, or there are obvious defects such as black streaks.

[Cleaning blade chip evaluation]
Using the commercially available electrophotographic copying machine (Docu Center Color 400 remodeled machine (manufactured by Fuji Xerox Co., Ltd., blade cleaning method)), 20,000 sheets of 20% density images were printed on each of the developers 1 to 7 above. Later, five full-tone halftone images with a density of 20% were printed, and then evaluated by observing the tip of the blade with an optical microscope. The evaluation results are shown in Table 1.
<Cleaning blade chip evaluation criteria>
○: The blade tip that contacts the image carrier is observed over the entire area, and there is no chipping.
-X: The blade tip contacting the image carrier is observed over the entire area, and there is at least one spot.

[Image carrier filming evaluation]
Using the commercially available electrophotographic copying machine (Docu Center Color 400 remodeled machine (manufactured by Fuji Xerox Co., Ltd., blade cleaning method)), 2000 000 images with a density of 5% were printed on each of the developers 1 to 7 above. Later, after printing five full-tone halftone images with a density of 20%, the image carrier was taken out and the state was visually observed. The evaluation results are shown in Table 1.
<Image carrier filming evaluation criteria>
○: The surface gloss is not lowered as compared with an unused image carrier.
X: There is a portion where the surface gloss is clearly reduced as compared with an unused image carrier.

[Initial fixing stable temperature range measurement]
After obtaining an unfixed image using a commercially available electrophotographic copying machine (Docu Center Color 400 remodeling machine (Fuji Xerox Co., Ltd.)), using a belt nip type external fixing machine, the fixing temperature is 90 ° C to 220 ° C. The fixing property and hot offset property of the image were evaluated while increasing the temperature gradually in increments of 5 ° C. The low temperature fixability is determined by fixing an unfixed solid image (25 mm x 25 mm) and then bending it with a weight under a certain load. Was the minimum fixing temperature. The hot offset temperature was set to the lowest temperature at which the corresponding white paper sheet was visually confirmed after one round of the fixing belt surface after fixing the unfixed image. The fixing stable temperature range was a temperature range between the minimum fixing temperature and a temperature obtained by subtracting 5 ° C. from the hot offset temperature. The evaluation results are shown in Table 1.

As shown in Examples 1 to 5 , the amount of low specific gravity toner having a specific gravity of 0.95 or less of the average specific gravity of the electrostatic charge developing toner is 0.1% by mass or more and 1% by mass or more. The toner in the range of 0.5 mass% or less exhibited sufficient low-temperature fixability, and there was no chipping or filming of the image carrier on the cleaning blade, resulting in no problem with the printed image.

Further, as shown in Comparative Example 1, when the amount of low specific gravity with a specific gravity of 0.95 or less of the average specific gravity of the electrostatic charge developing toner relative to the total amount of electrostatic charge developing toner is more than 1.5% by mass, The image carrier filming occurred, and a low-quality image with white spots and fog was obtained. Further, as shown in Comparative Example 2, when the amount of low specific gravity toner having a specific gravity of 0.95 or less of the average specific gravity of the electrostatic charge developing toner relative to the total amount of electrostatic charge developing toner is less than 0.1% by mass. In this case, chipping occurred partially at the tip of the cleaning blade in contact with the image carrier, and a low-quality image with black streaks due to poor cleaning was obtained.
That is, according to the electrostatic charge developing toner of the present invention, the amount of low specific gravity with a specific gravity of 0.95 or less of the average specific gravity of the electrostatic charge developing toner is 0.1% by mass or more with respect to the total amount of electrostatic charge developing toner. A high-quality image can be obtained while maintaining a low-temperature fixability equivalent to that of a toner outside the range of 1.5 mass% or less.

It is a figure which shows the temperature profile of the differential scanning calorimetry in this invention.

Claims (7)

In a non-magnetic electrostatic charge developing toner containing at least a polyester resin, a colorant , and a release agent , A × with respect to the average specific gravity (A) of the electrostatic charge developing toner in the electrostatic charge developing toner. A toner for developing an electrostatic charge, wherein the content (B) of a low specific gravity toner of 0.95 or less satisfies the following formula (1).
0.1% by mass ≦ B ≦ 1.5% by mass (1)   2. The electrostatic charge developing toner according to claim 1, wherein the electrostatic charge developing toner is prepared by a wet manufacturing method. The polyester resin, the electrostatic charge developing toner according to claim 1 or claim 2, wherein a crystalline polyester resin der Rukoto. The volume average particle size distribution index GSDv is 1.30 or less, and the ratio (GSDv / GSDp) between the volume average particle size distribution index GSDv and the number average particle size distribution index GSDp is 0.95 or more. toner for developing an electrostatic image according to any one of 3. An electrostatic latent image forming step of forming an electrostatic latent image on a pre-charged image carrier;
Developing the electrostatic latent image with a developer containing toner to form a toner image on the image carrier;
A transfer step of transferring the toner image formed on the image carrier onto a transfer target;
A cleaning step of removing the toner remaining on the image carrier after the toner image has been transferred onto the transfer body;
A fixing step of fixing the toner image transferred onto the transfer target;
In an image forming method including:
The toner image forming method which is a toner for developing an electrostatic image according to any one of claims 1 to 4. A method for producing an electrostatic charge developing toner according to any one of claims 1 to 4,
A resin fine particle dispersion in which the first resin fine particles containing the polyester resin are dispersed; a colorant particle dispersion in which the colorant is dispersed; and a release agent particle dispersion obtained by emulsifying the release agent; A first aggregating step of forming core agglomerated particles containing the first resin fine particles, the colorant, and the release agent particles by mixing at a rotation speed and dispersion time satisfying the following formula (2):
  A second aggregation step of forming a shell layer containing second resin fine particles on the surface of the core aggregated particles to obtain core / shell aggregated particles;
  A coalescence and coalescence step of fusing and coalescing by heating the core / shell aggregated particles to a glass transition temperature of the first resin fine particles or the second resin fine particles;
  A method for producing an electrostatic charge developing toner comprising:
10,000 (rpm · min) ≤ number of revolutions × dispersion time ≤ 100,000 (rpm · min) · · · Equation (2) A method for producing an electrostatic charge developing toner according to any one of claims 1 to 4,
  A resin fine particle dispersion in which the first resin fine particles containing the polyester resin are dispersed; a colorant particle dispersion in which the colorant is dispersed; and a release agent particle dispersion obtained by emulsifying the release agent; And a first aggregating step of forming core agglomerated particles containing the first resin fine particles, the colorant, and the release agent particles;
  A second aggregation step of forming a shell layer containing second resin fine particles on the surface of the core aggregated particles to obtain core / shell aggregated particles;
  A coalescing and coalescing step of fusing and coalescing the core / shell aggregated particles to a temperature equal to or higher than the glass transition temperature of the first resin fine particles or the second resin fine particles to form a toner dispersion;
  Adding the toner dispersion into a potassium iodide solution having an average specific gravity (A) of 0.95 and a specific gravity of 0.95 and removing the floating toner after standing for 24 hours;
  A method for producing an electrostatic charge developing toner comprising: