JP2005265989A - Toner for static charge development, and its manufacturing method, and developer for static charge development, and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner which maintains excellent releasability and a state with no roll mark in an oilless fixation and which exhibits image quality excellent in fixation characteristics, and to provide its manufacturing method, a developer and an image forming method. <P>SOLUTION: In the toner for static charge development containing a binder resin, a colorant and two or more kinds of mold release agents, difference of density between the principal mold release agent and the trace mold release agent is 0.02 or more, and total mixing ratio of the trace mold release agent is 0.1-15.0 mass%. The manufacturing method also includes an aggregation step, and difference of density between the principal mold release agent and the trace mold release agent is 0.02 or more, and a fusion/coalescence step after the aggregation step. Final total mixing ratio of the trace mold release agent in the mold release agents in the toner is 0.1-15.0 mass%. The developer for static charge development and the image forming method utilizing the toner for static charge development are also provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a toner for developing electrostatic charge used for developing an electrostatic latent image formed by electrophotography or electrostatic recording method, a method for producing the same, a developer for developing electrostatic image, and an image forming method. About.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In electrophotography, an electrostatic charge image is formed on a photoreceptor by charging and exposure processes, the electrostatic latent image is developed with a developer containing toner, and visualized through a transfer and fixing process.

  As the developer used here, a two-component developer composed of a toner and a carrier and a one-component developer using a magnetic toner or a non-magnetic toner alone are known. However, a kneading and pulverizing method in which a thermoplastic resin is melt-kneaded with a release agent such as a pigment, a charge control agent, and a wax, and then finely pulverized and classified after cooling is used as a method for producing the toner. 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 production apparatus. However, if the resin colorant dispersion is made brittle to satisfy these requirements, finer powder may be 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 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 photoreceptor, but the polyethylene on the surface layer is easily transferred by mechanical force, resulting in contamination of the developing roll, photoreceptor and carrier. It becomes easy and leads 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. In order to prevent these, if the flow aid is further increased, the generation of black spots on the photoreceptor and the scattering of the aid particles occur.

In recent years, a toner production method using an emulsion polymerization aggregation method has been proposed as a means for intentionally enabling control of the toner shape and surface structure (see, for example, Patent Documents 1 and 2). In general, a resin dispersion is prepared by emulsion polymerization or the like. On the other hand, after preparing a colorant dispersion in which a colorant is dispersed in a solvent, these are mixed to form an aggregate corresponding to the toner particle size, This is a method for producing toner by fusing and coalescing by heating.
The shape can be controlled to some extent by this method, and the chargeability and durability can be improved. However, since the internal structure is almost uniform, the peelability of the fixing sheet at the time of fixing, when OHP is output Problems remain in the stabilization of transparency and the existence of a difference in color between charges.

  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 increase the mechanical strength of the toner itself and to achieve both sufficient charging property and fixing property.

  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, with the simple reduction in size while maintaining the conventional particle size distribution, the presence of fine powder side toner causes significant problems of carrier and photoconductor contamination and toner scattering, making it difficult to achieve high image quality and high reliability at the same time. It is. 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 color-separated with B (blue), R (red), and G (green) filters, and then has a dot diameter of 20 to 70 μm corresponding to the original original. The latent image is developed using Y (yellow), M (magenta), C (cyan), and Bk (black) developers using the subtractive color mixing action. At this time, it is necessary to transfer a larger amount of developer compared to a conventional black-and-white machine, and since it is necessary to cope with a smaller dot diameter, uniform chargeability, durability, toner strength, and sharpness of particle size distribution. Is becoming increasingly important. 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.
In general, a polyolefin-based wax is internally added to the release agent component for the purpose of preventing low-temperature offset during fixing. Along with this, 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.

  Therefore, an oilless fixing toner in which a large amount of a release agent component is included in the toner has been proposed (for example, see Patent Document 3). 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 exudation 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 Mw and Tg of the binder, it is difficult to directly control the spinnability and cohesiveness at the time of fixing the toner. 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 or an oil-less method that compensates by introducing chemical crosslinking and consequently reduces the spinnability at the fixing temperature of the toner. A method for improving the peelability in fixing has been proposed (see, for example, Patent Documents 4 to 7).

  On the other hand, with regard to release agents, approaches to the problems of the oilless fixability, particularly oilless peelability, OHP transparency in full-color images, or toner powder fluidity inhibition caused by release agents have been studied and proposed. ing. Specifically, for the purpose of improving oil releasability, for example, the melting viscosity of the release agent is set to a middle temperature range, and an amorphous or low-crystalline release agent such as ester wax is applied to obtain a melt viscosity. Has been proposed to achieve low oil resistance, achieve oil-less peelability, and suppress OHP transparency inhibition of full-color images by this low crystal structure (see, for example, Patent Document 8).

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 necessary to introduce a cross-linked structure on the surface of the binder resin itself, to increase the molecular weight and Tg, to suppress the decrease in peelability due to plasticization, and to introduce a large amount of release agent. In particular, the image gloss is lowered and the transparency of the OHP is often impaired. Further, since a large amount of release agent is required, not only is it disadvantageous in cost, but also the amount of release agent on the fixed image is increased, and as a result, contact occurs when it is discharged after being fixed on the machine. Due to the roll, contact marks are generated in the release agent layer, and the image quality is impaired. This becomes more conspicuous as the image has a higher glossiness.
Japanese Patent Laid-Open No. 63-282275 JP-A-6-250439 JP-A-5-061239 JP-A-4-69666 Japanese Patent Laid-Open No. 9-258481 JP 59-218460 A JP 59-218459 A JP-A-6-337541

An object of the present invention is to provide an electrostatic charge developing toner that solves the above-mentioned problems in the conventional toner, and a method for producing the same.
That is, the object of the present invention is to maintain excellent releasability in oilless fixing, a state without a roll contact mark at the time of discharging a fixed image for a long period of time, and good fixed image surface glossiness and OHP transparency. An object of the present invention is to provide an electrostatic charge developing toner exhibiting fine image quality with excellent fixing characteristics, a method for producing the same, an electrostatic charge image developing developer, and an image forming method.

As a result of intensive studies to solve the above problems, the present inventors have conceived the present invention described below and found that the problems can be solved. That is, the present invention
<1> An electrostatic charge developing toner comprising at least a binder resin, a colorant, and two or more release agents,
Of the two or more types of release agents, the difference in density between the main release agent and the trace release agent having a smaller content than the main release agent is a value specified by ASTM D792, and is set to 0. 02 or more,
The toner for developing an electrostatic charge image, wherein a total mixing ratio of the trace release agent in the release agent is 0.1 to 15.0% by mass.

  <2> The electrostatic charge developing toner according to <1>, wherein the release agent has a refractive index of 1.5 to 1.6.

  <3> Resin fine particle dispersion used when producing toner, wherein toner has a shape factor of 110 to 140, and at least the main release agent has an SP value (solubility parameter) of 8.9 to 9.1. The SP value is 9.1 to 9.4, and the difference between the SP value of the main mold release agent and the SP value of the resin fine particle dispersion is 0.0 to 0.5. <1> or <2>. The electrostatic charge developing toner according to <1>.

<4> The complex viscosity η ^* a at a temperature of 85 ° C. and a measurement frequency of 6.28 rad / s determined from dynamic viscoelasticity measurement of the main release agent is 0.1 to 1.0 Pa · s, and The ratio (η ^* a / η ^* b) of the complex viscosity η ^* a to the complex viscosity η ^* b at a measurement frequency of 62.8 rad / s is 1.0 to 3.5. <1> to <3> The electrostatic charge developing toner according to any one of <1> to <3>.

  <5> The maximum value of endotherm obtained from the differential thermal analysis of the main release agent is 85 to 95 ° C, and the ratio of the component of 85 ° C or less obtained from the endothermic peak area to the total endothermic area is 15%. Any one of <> 1 to <4>, wherein the amount of the release agent in the toner determined from the height of the peak of the endothermic peak is 6 to 9% by mass. The toner for electrostatic charge development described in 1.

  <6> The viscosity ηs140 obtained from an E-type viscometer provided with a cone plate having a cone angle of 1.34 ° at 140 ° C. of the main mold release agent is 1.5 to 5.0 mPa · s. <1> to <5>. The electrostatic charge developing toner according to any one of <1> to <5>.

  <7> The electrostatic charge developing toner according to any one of <1> to <6>, wherein an average value of a maximum length of the release agent in observation with a transmission electron microscope is 200 to 1500 nm. is there.

  <8> The electrostatic charge developing device according to any one of <1> to <7>, wherein the area ratio of the release agent crystal to the toner in the transmission electron microscope observation is 10 to 30%. Toner.

  <9> A coating layer exists in the toner, the thickness thereof is 0.1 to 0.3 μm, and the amount of the release agent present on the surface of the coating layer determined from XPS is 11 to 30 atm%. The electrostatic charge developing toner according to any one of <1> to <8>, wherein the toner is an electrostatic charge developing toner.

The present invention also provides:
<10> Aggregated particle dispersion in which a colorant dispersion and a release agent dispersion are mixed in a resin fine particle dispersion in which resin fine particles of 1 μm or less are dispersed, and an aggregating agent is added thereto to disperse agglomerated particles. A method for producing an electrostatic charge image developing toner comprising an aggregation step of preparing a liquid,
The difference in density between the main mold release agent contained in the mold release agent dispersion and the micro mold release agent having a smaller content than the main mold release agent is a value specified by ASTM D792, and is 0.02 or more. And
After the aggregation step, including a fusion and coalescence step of fusing and coalescing by heating to a temperature above the glass transition point of the resin fine particles,
Finally, it is a method for producing a toner for developing an electrostatic charge, wherein the total mixing ratio of the trace release agent in the release agent in the toner is 0.1 to 15.0% by mass.

  <11> Between the aggregation step and the fusion step, a resin particle dispersion in which the resin fine particles are further dispersed is added to the aggregated particle dispersion in which the aggregated particles are dispersed, and the aggregated particles are mixed with the resin particles. The method for producing a toner for developing an electrostatic charge image according to claim <10>, further comprising an adhesion step of adhering resin fine particles.

Furthermore, the present invention provides
<12> An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to any one of <1> to <9>.

The present invention also provides:
<13> A latent image forming step of forming a latent image on the latent image carrier, a developing step of developing the latent image using an electrostatic image developing toner on the developer carrier, and the development after development An image forming method comprising: a transfer step of transferring an image to a recording medium; and a fixing step of fixing the developed image transferred to the recording medium,
The electrostatic charge image developing toner is the electrostatic charge image developing toner according to <1>.
In the image forming method, the fixing in the fixing step is oilless fixing.

  According to the present invention, excellent releasability is maintained in oilless fixing, a state without a roll contact mark at the time of discharging a fixed image is maintained for a long time, and fixing such as good fixed image surface glossiness and OHP transparency is achieved. It is possible to provide a toner for developing an electrostatic charge satisfying fine image quality having excellent characteristics, a method for producing the same, a developer for developing an electrostatic charge image, and an image forming method.

  Hereinafter, the electrostatic charge developing toner of the present invention, a method for producing the same, a developer for developing an electrostatic charge image, and an image forming method will be described in detail.

[Method for producing toner for developing electrostatic image]
The electrostatic image developing toner of the present invention is produced by the following method.
That is, first, a resin fine particle dispersion in which resin fine particles of 1 μm or less are dispersed, a colorant particle dispersion, one or more release agent particle dispersions, and an inorganic fine particle dispersion added as necessary are prepared.
At this time, in particular, the difference in density between the main mold release agent contained in the mold release agent dispersion and the minute mold release agent having a smaller content than the main mold release agent is a value specified by ASTM D792. 0.02 or more.

Next, aggregating agents are added and ionically neutralized while mixing and stirring a predetermined amount thereof to form aggregates (aggregated particles) of the respective particles (aggregation step).
At this time, the concentrations of the main release agent and the minute release agent are adjusted so that the total mixing ratio of the minute release agents in the release agent in the toner is 0.1 to 15.0% by mass. deep.

  After the aggregation step, a desired toner particle size can be obtained by additionally adding resin fine particles before reaching the desired toner particle size (attachment step). Next, after adjusting the pH of the system from a weakly acidic to a neutral range with an inorganic hydroxide, it is heated to a temperature higher than the glass transition temperature of the resin fine particles, and united and fused (fusion and uniting step). After completion of the reaction, sufficient washing is performed, and the electrostatic charge image developing toner of the present invention is produced through a solid-liquid separation process and a drying process.

The resin fine particles are generally produced by emulsion polymerization or the like.
Using a resin dispersion of an ionic surfactant of resin fine particles, a pigment dispersed with the same or opposite polarity ionic surfactant is mixed, and a flocculant is added to cause heteroaggregation. Next, resin fine particles are added to this, and the toner particles are aggregated and adhered to the surface to form toner-aggregated particles, and then heated above the glass transition point of the resin to fuse and coalesce the aggregates, and wash and dry. Depending on the method, the toner shape is preferably from indefinite to spherical.

As a specific example of the flocculant, a compound having a monovalent or higher charge is preferable. Specific examples of the compound include water-soluble surfactants such as the above-described ionic surfactants and nonionic surfactants, hydrochloric acid, and the like. Acids such as sulfuric acid, nitric acid, acetic acid, oxalic acid, magnesium chloride, sodium chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate, inorganic acid metal salts, sodium acetate, potassium formate , Aliphatic acids such as sodium oxalate, sodium phthalate, potassium salicylate, metal salts of aromatic acids, metal salts of phenols such as sodium phenolate, metal salts of amino acids, triethanolamine hydrochloride, aniline hydrochloride, etc. And inorganic acid salts of aliphatic and aromatic amines.
Preferable flocculants include metal salt polymers, specifically tetravalent aluminum salt polymers or tetravalent aluminum, and more specifically polyaluminum chloride.

  Further, even if the process is performed by mixing and agglomerating all at once, in the agglomeration step, the balance of the initial amount of the ionic dispersant of each polarity is shifted in advance, for example, inorganic such as calcium nitrate. This is ionically neutralized by using a metal salt or a polymer of inorganic metal salt such as polyaluminum chloride to form a first-stage matrix aggregation below the glass transition point, and after stabilization, as a second stage Add a particle dispersion treated with a polarity and amount of dispersant that compensates for the imbalance, and if necessary, heat it slightly below the glass transition point of the resin contained in the matrix or additional particles. After stabilization at a high temperature, the particles added in the second stage of agglomeration by heating to the glass transition point or higher may be combined together while adhering to the surface of the base agglomerated particles. Furthermore, the stepwise operation of aggregation may be repeated several times.

  Moreover, you may make 6-9 mass% of main mold release agents or trace amount mold release agents contain in the resin particle. In this case, it is preferable from the viewpoint of chargeability and durability to add before adding the additional particles. The toner particle size in the present invention is preferably 3 to 9 μm, and more preferably 3 to 8 μm. When the particle size is less than 3 μm, the chargeability becomes insufficient and the developability may deteriorate, and when it exceeds 9 μm, the resolution of the image decreases.

The particle size distribution index of the present invention is such that the volume average particle size distribution index GSDv is at most 1.30, and the ratio of the volume average particle size distribution index GSDv to the number average particle size distribution index GSDp is at least 0.95. It is preferable to do.
By setting the volume distribution index GSDv to 1.30 or less, high resolution can be maintained. By setting the ratio of the volume average particle size distribution index GSDv and the number average particle size distribution index to 0.95 or more, image defects such as scattering and fogging can be prevented at the same time without lowering the chargeability.

  The particle size and particle size distribution index are, for example, particle size ranges obtained by dividing the particle size distribution measured using a measuring instrument such as Coulter Counter TAII (manufactured by Beckman-Coulter) or Multisizer II (manufactured by Beckman-Coulter). For (channel), draw a cumulative distribution from the small diameter side for each volume and number, define the particle size to be 16% cumulative as volume D16%, or several 16%, and the particle size to be 50% cumulative, It is defined as a volume D50% or a number D50%. Furthermore, it is defined as a volume D84% or a number D84%. Using these, the volume average particle size distribution index (GSDv) is obtained from D84v / D16v, and the number average particle size index (GSDp) is calculated from D84p / D16p.

  The absolute value of the charge amount of the electrostatic charge developing toner in the present invention is preferably 20 to 40 μC / g, more preferably 15 to 35 μC / g. If the charge amount is less than 20 μC / g, background stains (fogging) are likely to occur, and if it exceeds 40 μC / g, the image density tends to decrease. Further, the ratio of the charge amount in the summer (high temperature and high humidity) and the charge amount in the winter (low temperature and low humidity) of the toner for developing an electrostatic charge is preferably 0,5 to 1,5, preferably 0,7 to 1. , 3 are more preferable. When the ratio is outside these ranges, the charging property is highly dependent on the environment, and the charging stability is poor, which is not preferable for practical use.

  The polymer (binder resin material) used in the resin particles used in the present invention is not particularly limited. For example, styrenes such as styrene, parachlorostyrene, and α-methylstyrene, methyl acrylate, and acrylic acid Vinyl such as ethyl, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate Esters having a group; 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; ethylene, propylene , Monomers such as polyolefins such as butadiene, beta CEA (beta-carboxyethyl acrylate) may be used polymers such as.

Further, as the crosslinking component, for example, acrylic acid esters such as pentanediol diacrylate, hexanediol diacrylate, decanediol diacrylate, and nonanediol diacrylate can be used.
In addition, polymers such as these monomers, copolymers obtained by combining two or more of these, or mixtures thereof, as well as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyethers Examples thereof include a resin, a non-vinyl condensation resin, a mixture of these with the vinyl resin, and a graft polymer obtained when a vinyl monomer is polymerized in the presence of these.

  In the case of vinyl monomers, emulsion polymerization can be performed using an ionic surfactant or the like to prepare a resin particle dispersion. In the case of other resins, the resin is oily and has a relatively high solubility in water. If it is soluble in a low solvent, dissolve the resin in those solvents, disperse the particles in water with a disperser such as a homogenizer together with an ionic surfactant or polymer electrolyte, and then heat or depressurize the solvent. The resin dispersion liquid can be prepared by evaporating.

  Moreover, the particle diameter of the resin particle in the obtained resin fine particle dispersion is measured, for example, with a laser diffraction type particle size distribution measuring apparatus (LA-700, manufactured by Horiba, Ltd.).

  Examples of surfactants used in the present invention for emulsion polymerization, pigment dispersion, resin particles, release agent dispersion, aggregation, or stabilization thereof include sulfate ester, sulfonate, and phosphate ester types. , Soap type anionic surfactants, amine salt type, quaternary ammonium salt type cationic surfactants, polyethylene glycol type, alkylphenol ethylene oxide adduct type, polyhydric alcohol type nonionic surface active It is also effective to use an agent in combination, and general means such as a rotary shear homogenizer, a ball mill having a media, a sand mill, and a dyno mill can be used for dispersion.

  After completion of the aggregation and fusion, a desired toner is obtained through an arbitrary washing step, solid-liquid separation step, and drying step. In the washing step, it is preferable to sufficiently perform substitution washing with ion-exchanged water from the viewpoint of chargeability. 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 for electrostatic image development]
The electrostatic image developing toner of the present invention (hereinafter sometimes simply referred to as “toner”) includes at least a binder resin, a colorant, and two or more release agents. Hereinafter, these will be described. The details of the binder resin are as described in the method for producing a toner for developing an electrostatic charge image of the present invention described above.

(Release agent)
And as a mold release agent used for this invention, each contains at least 1 sort (s) of the main mold release agent with a large content, and the trace mold release agent with a smaller content than the main mold release agent. Here, the “main release agent” refers to a release agent contained in the toner having a content of 5% by mass or more (preferably 5 to 15% by mass). In some cases, there may be two or more. Further, the “trace release agent” is a release agent having a smaller content than the main release agent. Specifically, among the release agents contained in the toner, the content is 3% by mass or less. (Preferably, 0.05 to 2.5% by mass) is used, and there may be only one type, or there may be two or more types.

In the present invention, the difference (A−B) between the density (A) of the main release agent and the trace release agent (B) is a value specified by ASTM D792 and is 0.02 or more. .
In other words, in the case of a polymer having a micro interface inside due to crystallinity or the like, scattering occurs at the interface, so that the amount of light transmitted is reduced, and even when the amount of the release agent added is small, It adversely affects OHP transparency, fixed image surface gloss and color development. For the purpose of preventing and improving this, as a structure that inhibits crystal growth and prevents the formation of a micro interface inside the polymer material (main mold release agent) that serves as a matrix with a function as a mold release agent, Means for mixing or compatibilizing materials having different properties are conceivable. At this time, when the maximum reforming effect is achieved by addition of a very small amount without impairing the performance of the base polymer material having a function as a mold release agent, the density specified in ASTM D792 Mixing of a minute amount of mold release agent having a difference of 0.02 or more is extremely important.

“Mixing” as used herein refers to a physical mixture obtained by adding and stirring a trace component in a molten state to a base polymer material, or a mixture formed as a separate component / subcomponent by reaction control during polymer polymerization. Even if it is obtained by the combined use, it does not matter as long as it conforms to the above definition (the difference in the predetermined density).
The difference in density is preferably 0.02 to 0.50, and more preferably 0.02 to 0.20. In addition, in the difference in density, when there are a plurality of types of main release agents and trace release agents, it is preferable that the density difference between each main release agent and each trace release agent is in the above range. .

In addition, the mixing ratio of the trace release agents in the release agent (when there are two or more trace release agents, the total mixing ratio thereof) is 0.1 to 15.0 mass%.
When the mixing ratio is less than 0.1% by mass, the modifying function as a release agent for toner is not sufficiently exhibited. Conversely, when it exceeds 15% by mass, the binder resin and the release agent are not used. The function as a release agent is likely to be impaired in terms of compatibility between the constituting molecular materials. The mixing ratio is preferably 0.5 to 12% by mass, and more preferably 3 to 10% by mass.

  The refractive index of the release agent is a value defined by ASTM D792, and is preferably 1.5 to 1.6, and more preferably 1.52 to 1.57. When the refractive index exceeds 1.6, the transparency of the toner itself is impaired, which may adversely affect toner characteristics such as the fixed image surface glossiness / coloring property and OHP transparency. On the other hand, when the refractive index is less than 1.5, the difference in refractive index from the toner binder resin becomes too large, and light scattering at the interface becomes remarkable. May adversely affect the toner characteristics such as the property and OHP permeability.

At least the SP value (solubility parameter) of the main release agent is preferably 8.9 to 9.1, and the SP value of the resin fine particle dispersion when preparing the toner is 9.1 to 9.4. It is preferable that
Since the SP value (solubility parameter) of the main release agent is 8.9 to 9.1, the compatibility with the binder resin is improved, so that the release agent is uniformly dispersed in the toner. Can do. Therefore, expected gloss, peeling, and HOT offset characteristics can be provided, and further, the amount of the release agent on the surface can be reduced, so that the storage property can be maintained. The SP value is more preferably 9.0 to 9.1. In addition, when there are a plurality of types of the main release agents, at least one of them is in the range of the SP value, and the difference between the SP value of the main release agent described later and the SP value of the resin fine particle dispersion is in the range described later. However, from the viewpoint of obtaining good transparency and a fixed image, it is preferable that all main release agents satisfy the above two conditions.

  When the SP value of the resin fine particle dispersion at the time of producing the toner is 9.1 to 9.4, the compatibility between the binder resin and the release agent can be maintained. As a result, the release agent can be dispersed in the toner, and the same effect as in the case of the SP value of the main release agent can be expected. The SP value is more preferably 9.25 to 9.4.

The difference (X−Y) between the SP value (X) of the main mold release agent and the SP value (Y) of the resin fine particle dispersion is preferably 0.0 to 0.5.
If the difference in SP value is 0.5 or less, it becomes easy to be compatible with the resin, and when the toner is fixed, the main release agent is uniformly dissolved, so that it is difficult to generate a roll mark, and in terms of peelability. Also, the unevenness in the fixed image is eliminated. However, if the ratio is larger than 0.5, the main mold release agent and the resin dispersion are hardly compatible, and the main mold release agent is locally present in the toner. For this reason, the main parting agent is shifted to a part of the fixed image, so that the part becomes a film thickness and uneven glossiness or roll marks are likely to occur.

  Moreover, crystallinity falls by mix | blending a trace amount mold release agent compared with the case of a mold release agent alone. For this reason, even if there is a difference in cooling rate between the discharge part of the EXIT roll bonding part and the discharge part of the non-contact part, the roll mark can be reduced. With a release agent alone, roll marks are likely to occur.

Here, the “SP value” is a solubility parameter, which is a numerical value characterizing the solubility of a solvent, resin, polymer, or the like. Solvents, resins, and polymers with closer SP values are easier to dissolve, and vice versa.
The SP value may be calculated from the surface tension, but generally the SP value is obtained from the chemical structure and specific gravity. In the present invention, the SP value can be determined from the chemical structure and calculated from the following formula (1). References include “paint flow and pigment dispersion” (Kyoritsu Shuppan Co., Ltd.).

Formula (1): δ = σΣ (G / M)
(Δ: SP value, ρ: specific gravity, M: molecular weight (repeating unit is used in polymer), G: chemical binding constant)

  The main mold release agent preferably has a main maximum peak measured in accordance with ASTM D3418-8 at 85 to 95 ° C. If it is less than 85 ° C., an offset tends to occur during fixing. On the other hand, if it exceeds 95 ° C., the fixing temperature becomes high, and the smoothness of the surface of the fixed image cannot be obtained, and the glossiness may be impaired.

  For the measurement of the main maximum peak, for example, DSC-7 manufactured by Perkin Elmer can be used. It is preferable to use the melting points of indium and zinc for the temperature correction of the detection part of the apparatus, and to use the heat of fusion of indium for the correction of the amount of heat. The sample is preferably an aluminum pan, an empty pan is set as a control, and the measurement is performed at a heating rate of 10 ° C./min.

  The maximum value of endotherm obtained from the differential thermal analysis of the main release agent is preferably from 85 to 95 ° C, and more preferably from 86 to 93 ° C. When the temperature is less than 85 ° C., the melt viscosity becomes low and the dissolution property at the time of oilless fixing is improved, but when the toner is produced by the hetero-aggregation method, the release agent is easily melted. Not only does the encapsulating property deteriorate and the particle size controllability is impaired, but the amount of the surface release agent increases, which may impair the powder flowability of the toner. On the other hand, when the temperature exceeds 95 ° C., the production stability is improved, but the melt viscosity is increased. Therefore, the release property of the release agent in oilless fixing may be lowered, and the oilless peelability may be lowered.

Further, the ratio of the component at 85 ° C. or lower (low melting point component) determined from the endothermic peak area to the total endothermic area is preferably 15% or less, more preferably 5 to 15%, and more preferably 7 to 13 % Is more preferable.
When the amount of the low melting point component of 85 ° C. or less exceeds 15%, plasticity occurs, so that the release property of the release agent at the time of fixing is lowered, and as a result, the oilless peelability may be impaired.

  The amount of the release agent in the toner obtained from the peak height of the endothermic maximum value in the differential thermal analysis is preferably 6 to 9% by mass. More preferably, it is 6.5-8.5 mass%. If the amount of the release agent is less than 6% by mass, the amount of elution sufficient for peeling during oilless fixing cannot be obtained, the peelability is impaired, and the fixing surface becomes rough. . If it exceeds 9% by mass, the releasability will be good, but the amount of the release agent on the toner surface and the fixed image will increase, which will not only reduce the powder fluidity of the toner but also when discharging the fixed image. In some cases, a roll mark such as a discharge roll is generated, and the image quality is impaired.

  The viscosity ηs140 obtained from an E-type viscometer equipped with a cone plate having a cone angle of 1.34 ° at 140 ° C. of the main mold release agent is preferably 1.5 to 5.0 mPa · s. More preferably, it is 2.5 to 4.0 mPa · s. When the viscosity is lower than 1.5 mPa · s, the elution property at the time of fixing is good, but the release agent layer formed on the fixed image becomes non-uniform, causing uneven peeling and visually uneven image gloss. May cause. In addition, if it is higher than 5.0 mPa · s, the elution property is lowered, so that a release agent component sufficient for releasing the image and the fixing roll at the time of oilless fixing is not supplied, and a peeling failure occurs. Sometimes.

  Examples of the polymer material constituting the release agent as described above are not particularly limited as long as the above requirements are satisfied. Montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, microcrystalline. Minerals such as wax and Fischer-Tropsch wax, petroleum wax, natural gas wax and modified products thereof; low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones which show a softening point by heating, oleic amide, Fatty acid amides such as erucic acid amide, ricinoleic acid amide, stearic acid amide; plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax ; Examples of the modifying auxiliary component include higher alcohols having 10 to 18 carbon atoms and mixtures thereof; higher fatty acid monoglycerides having 16 to 22 carbon atoms and mixtures thereof; Can be used in combination.

In particular, as the main release agent, it is preferable to use at least one or a combination of two or more low molecular weight polyolefins such as polyethylene, polypropylene and polybutene.
As the micro-release agent, among the above-mentioned release agents, those having a reduced content with a release agent different from the main release agent can be used. Furthermore, fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, stearic acid amide, etc .; plant waxes such as rice wax, candelilla wax, tree wax, jojoba oil, etc .; animals such as beeswax And waxes. These wax types are preferably used in combination of at least one or two or more.
Then, as described above, the electrostatic charge of the present invention is combined so that the density difference between the main mold release agent and the micro mold release agent is a value specified by ASTM D792 and 0.02 or more. A release agent used for image developing toner.

  The above-mentioned polymer materials constituting the release agent can be dispersed in water together with ionic surfactants, polymer electrolytes such as polymer acids and polymer bases, heated above the melting point and subjected to strong shearing. It is made into a fine particle by a homogenizer or a pressure discharge type disperser (Gorin homogenizer, manufactured by Gorin Co., Ltd.) and is prepared in a state of a dispersion liquid (release agent dispersion liquid) in which particles (release agent particles) of 1 μm or less are dispersed.

The particle size of the release agent particles in the obtained release agent particle dispersion is measured, for example, with a laser diffraction particle size distribution analyzer (LA-700, manufactured by Horiba, Ltd.).
In addition, for example, an ARES measuring device manufactured by Rheometric Scientific is used for measuring the dynamic viscoelasticity of the release agent. In the dynamic viscoelasticity measurement, after forming into a tablet, it is usually set on a parallel plate with a diameter of 50 mm, the normal force is set to 0, and a sinusoidal vibration is applied at a vibration frequency of 6.28 to 62.8 rad / s. .

  The measurement is performed at 90 ° C. with the gap between the parallel plates set to 1.0 mm. The temperature is controlled by controlling the temperature in the measurement system. The measurement time interval is preferably 30 seconds, and the temperature adjustment accuracy after the start of measurement is preferably ± 1.0 ° C. or less from the viewpoint of measurement accuracy. Further, during the measurement, the strain amount is appropriately maintained at each measurement temperature, and is adjusted as appropriate so that an appropriate measurement value can be obtained.

  In general, a crystalline material such as a release agent usually changes into a glass region, a transition region (crystal melting), a rubbery region, and a fluid region as the temperature rises from the state, that is, the motion state of the molecular chain. Among these state changes, the glass region is in a state where the movement of the main chain of the polymer is frozen at a temperature below the glass transition temperature (Tg), but as the temperature rises and the movement of the molecules increases. It gradually becomes softer from the glass state, and after passing through the transition region of crystal melting, it finally shows a fluid state. Although the movement of the main chain is certainly frozen in the glass state, the movement of the side chain is still frozen, but the movement of the side chain is also frozen by further lowering the temperature. These dispersions include viscoelastic dispersions called α dispersion, β dispersion, and γ dispersion from the higher temperature side. The α dispersion is called main dispersion, which is caused by thermal motion of the polymer main chain segment on a large scale, and the maximum value of the loss tangent is called the glass transition temperature. This dispersion is caused by the fact that the microbrown motion of the frozen main chain segment is released at the glass transition temperature at a low temperature (glass state) below the glass transition temperature. This is due to small segments or rotational movement of the side chains. Further, γ dispersion is caused by a smaller molecular motion.

  Dynamic viscoelasticity depends on the frequency at the time of dynamic viscoelasticity measurement, and when the frequency is high, the elasticity tends to increase. Further, when the frequency is low, the elasticity is small. Furthermore, these properties are also affected by properties such as the structure and molecular weight of the substance. Furthermore, in the electrophotographic process, since speed, that is, frequency influences, it is possible to express necessary characteristics in a dynamic environment by accurately defining these characteristics. In addition, since there is frequency (speed) dependence regarding the molecular structure, it is important to define these frequency response characteristics. In addition, it is generally known that the characteristics of the value-added material greatly change with the melting point, but considering the melting of the release agent in the fixing process in a short time, it is determined from the solid in the toner. These properties are greatly affected in the temperature range where the molten state and the solid state coexist near the melting point of the release agent. Theoretically, the melting point is a temperature at which the crystal melts. However, since these crystalline substances have a distribution, there actually exists a state in which the crystal and the melting coexist within the melting point ± 10 ° C. For this reason, in this invention, the dynamic viscoelasticity measurement at the temperature of 85 degreeC is performed.

The complex viscosity η ^* a at a temperature of 85 ° C. and a measurement frequency of 6.28 rad / s determined from the dynamic viscoelasticity measurement of the main release agent is preferably 0.1 to 1.0 Pa · s (more preferably is 0.15~0.8Pa · s), and the ratio between the complex viscosity eta ^* b during the complex viscosity eta ^* a and the measured frequency ^{62.8rad / s (η * a /} η * b) Is preferably 1.0 to 3.5 (more preferably 1.0 to 3.3).
When the complex viscosity η ^* a is less than 0.1 Pa · S, not only does the release agent layer eluted during fixing heating not be uniform on the image, but also when the release roller is heated and pressed with a fixing roll. The form layer may become non-uniform (film breakage), and uneven peeling may occur. On the other hand, if it exceeds 1.0 Pa · s, the elution property is lowered, and not only the peelability is deteriorated but also the fixability may be deteriorated.

For the measurement of the dynamic viscoelasticity of the release agent, a complex viscosity η ^* obtained from frequency dispersion measurement at frequencies of 6.28 rad / s and 62.8 rad / s by a sinusoidal vibration method and a temperature range of 90 ° C. is preferably used. .

If “η ^* a / η ^* b” is less than 1.0, the elution property during fixing is good, but the release agent layer is non-uniform (film breakage), and peeling unevenness during oilless fixing is caused. May occur. On the other hand, if it exceeds 3.3, the elution property is lowered and peeling inhibition may occur.

(Coloring agent)
Known colorants can be used in the present invention. For example, examples of the black pigment include carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, nonmagnetic ferrite, and magnetite.

  Examples of yellow pigments include yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, hansa yellow, hansa yellow 10G, benzidine yellow G, benzidine yellow GR, selenium yellow, quinoline yellow, and permanent yellow NCG. Can be given.

  Examples of the orange pigment include red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange G, indanthrene brilliant orange RK, indanthrene brilliant orange GK and the like.

  Red pigments include Bengala, cadmium red, red lead, mercury sulfide, watch young red, permanent red 4R, risor red, brilliantamine 3B, brilliantamine 6B, dapon oil red, pyrazolone red, rhodamine B rake, lake red C Rose Bengal, Eoxin Red, Alizarin Lake and the like.

  Blue pigments include bitumen, cobalt blue, alkali blue rake, Victoria blue rake, fast sky blue, indanthrene blue BC, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, phthalocyanine green, malachite green oxare. Rate.

Examples of purple pigments include manganese purple, fast violet B, and methyl violet lake.
Examples of the green pigment include chromium oxide, chromium green, pigment green, malachite green lake, final yellow green G, and the like.
Examples of white pigments include zinc white, titanium oxide, antimony white, and zinc sulfide.
Examples of extender pigments include barite powder, barium carbonate, clay, silica, white carbon, talc, and alumina white.

  Examples of the dye include various dyes such as basic, acidic, dispersed, and direct dyes, such as nigrosine, methylene blue, rose bengal, quinoline yellow, and ultramarine blue.

Moreover, as a coloring agent, these can be used individually or in mixture, and also in the state of a solid solution. These are dispersed by a known method. For example, a rotary shearing 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.
Further, these colorants are dispersed in an aqueous system by the homogenizer using a polar surfactant.

The colorant is selected from the viewpoints of hue angle, saturation, brightness, weather resistance, OHP permeability, and dispersibility in the toner. The addition amount of the colorant contained in the toner is 1 to 20 parts by mass with respect to 100 parts by mass of the binder resin.
When a magnetic material is used for the black colorant, 30 to 100 parts by mass is added unlike other colorants.

  Further, when the toner is used as a magnetic toner, magnetic powder may be contained. As such magnetic powder, a substance magnetized in a magnetic field is used, and it is a ferromagnetic powder such as iron, cobalt, or nickel, or a compound such as ferrite or magnetite.

  In particular, in the present invention, in order to obtain toner in the aqueous layer, it is necessary to pay attention to the water layer's ability to migrate, dissolve and oxidize, and surface modification, for example, hydrophobization treatment, etc. is preferably performed. Is preferred.

The shape factor SF1 of the toner for developing an electrostatic charge image of the present invention is preferably from 110 to 140, more preferably from 110 to 120, from the viewpoint of good image formability. The shape factor SF1 (average value of shape factor (square of perimeter / projected area)) is calculated by, for example, the following method.
That is, the optical microscope image of the toner dispersed on the slide glass is taken into a Luzex image analyzer through a video camera, and the “square of the circumference of 50 or more toners / projection area” (ML2 / A) is calculated and averaged. It is obtained by calculating the value.

In the toner of the present invention, it is preferable that the release agent includes a rod shape and a lump shape, and the size thereof is 200 to 1500 nm in observation with a transmission electron microscope (TEM). The rod-shaped release agent crystals are eluted at the initial stage upon melting at the time of fixing, and then the bulk crystals are melted to show the supply stability of the release agent layer in oilless peeling. For this reason, it is preferable that both exist.
The “bar shape” means a shape in which the aspect ratio (long side / short side) of the release agent image obtained from the TEM observation image is 2.0 or more. The “lumb shape” means a shape in a range outside the aspect ratio.

Moreover, it is preferable that the magnitude | size (average value of maximum length) of the mold release agent observed from a transmission electron microscope image is 200-1500 nm. More preferably, it is 250-1000 nm.
If it is less than 200 nm, sufficient elution cannot be obtained even when melted during fixing, and peeling stability may not be obtained. If it exceeds 1500 nm, crystals in the visible light range may remain after fixing, and the transparency of the transmitted image may be impaired.

  The area (projected area) ratio of the release agent crystals to the toner in the transmission electron microscope observation is preferably 10 to 30%, more preferably 15 to 25%. If it is less than 10%, the release agent at the time of fixing is not sufficiently continuously supplied, and peeling unevenness in the peeling process may occur. On the other hand, if it exceeds 30%, crystals of visible light or more may remain in the image even after fixing, and the transparency of the image may be impaired. These are particularly noticeable during high-speed fixing.

  When the coating layer is present in the toner of the present invention, the thickness is 0.1 to 0.3 μm, and the amount of the release agent present on the coating layer surface determined from XPS is 11 to 30 atm%. It is preferable. The presence and thickness of the coating layer can be observed with a transmission electron microscope.

If the thickness of the coating layer is less than 0.1 μm, the surface uniformity is lowered and the amount of the release agent present in the surface layer of the toner is increased, so that the powder fluidity is lowered and the transferability is only impaired. In addition, agglomerates in the developing machine may be formed, resulting in image defects such as white streaks. On the other hand, if it exceeds 0.3 μm, the elution of the release agent at the time of oilless fixing may be inhibited, and the oilless peelability may be lowered.
Further, if the amount of the surface release agent of the toner detected by XPS is less than 11 atm%, the oilless peelability may be impaired, and if it exceeds 30 atm%, the fluidity of the toner may be lowered.

  Quantification of the release agent present on the toner surface using XPS can be performed using an X-ray photoelectron spectrometer (JPS-9000MX: manufactured by JEOL Ltd.). Specifically, the toner having a coating layer is measured, and the following calculation formula is obtained from the total detected amount of carbon derived from components other than the release agent and the total detected amount of carbon derived from the release agent. Can be quantified on the basis.

(Calculation formula): “Amount of release agent present on toner surface” = [(peak area derived from 1s orbital of carbon atom of release agent) / (peak area derived from 1s orbital of carbon atom on toner surface)

  In the present invention, a charge control agent can be used to improve and stabilize 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. A material that is difficult to dissolve in water is preferable from the viewpoint of controlling the ionic strength that affects aggregation and temporary stability and reducing wastewater contamination.

  In the present invention, the inorganic fine particles can be added in a wet manner in order to stabilize the chargeability. Examples of inorganic fine particles to be added include silica, alumina, titania, calcium carbonate, magnesium carbonate, and tricalcium phosphate, all of which are usually used as external additives on the toner surface, such as ionic surfactants, polymer acids, It can be used by dispersing with a molecular base.

  For the purpose of imparting fluidity and improving cleaning properties, after drying in the same way as normal toner, inorganic particles such as silica, alumina, titania and calcium carbonate, and resin fine particles such as vinyl resin, polyester and silicone are sheared in a dry state. To the surface and used as a fluidity aid or cleaning aid.

[Developer for developing electrostatic image]
The developer for developing an electrostatic image of the present invention contains the toner for developing an electrostatic image of the present invention described above.
That is, the developer for developing an electrostatic image of the present invention (hereinafter sometimes simply referred to as “developer”) is produced by mixing the toner described above and the following carrier. The mixing ratio (mass ratio) of toner and carrier in the developer is preferably in the range of toner: carrier = 1: 99 to 20:80, and preferably in the range of 3:97 to 12:88. More preferred.

(Career)
There is no restriction | limiting in particular as a carrier which can be used for the developing agent of this invention, A well-known carrier can be used. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which magnetic powder or the like is dispersed in a matrix resin may be used.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins, urea resins, urethane resins, melamine resins, etc. It is not limited.

  In general, the carrier preferably has an appropriate electric resistance value, and it is preferable to disperse the conductive fine powder in the resin for adjusting the resistance. Examples of the conductive fine powder include metals such as gold, silver and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. However, it is not limited to these.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, a magnetic material is used. Preferably there is. The volume average particle size of the carrier core material is preferably in the range of 10 to 100 μm, and more preferably in the range of 25 to 50 μm.

  In order to coat the surface of the core material of the carrier with a resin, a method of coating the coating resin and, if necessary, various additives with a solution for forming a coating layer dissolved in an appropriate solvent is employed. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include a dipping method in which the powder of the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the carrier core material, and a carrier core material. Examples thereof include a fluidized bed method in which a coating layer forming solution is sprayed in a state of being suspended by flowing air, and a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater to remove the solvent.

(Image forming method)
The image forming method of the present invention will be described in detail below. The image forming method of the present invention uses a latent image forming step of forming a latent image (electrostatic latent image) on a latent image carrier and the electrostatic image developing toner on the developer carrier. A development process for developing the toner image, a transfer process for transferring the developed image after development to a recording medium, and a fixing process for fixing the development image transferred to the recording medium. As described above, the electrostatic image developing toner of the present invention is used, and the fixing in the fixing step is oilless fixing. The same effect can be obtained by using the developer for developing an electrostatic charge image of the present invention instead of the toner.

  The latent image forming step is a step of forming an electrostatic latent image by uniformly charging the surface of the latent image carrier with a charging means and then exposing the latent image carrier with a laser optical system or an LED array. is there. Examples of the charging means include a non-contact charger such as corotron and scorotron, and a contact method in which a latent image carrier surface is charged by applying a voltage to a conductive member in contact with the latent image carrier surface. Any type of charger may be used. However, a contact charging type charger is preferable 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 roller shape, and the like, but a roller-like member is preferable. The image forming method of the present invention is not subject to any particular limitation in the latent image forming process.

  The development step refers to bringing a developer carrier having a developer layer containing at least toner on the surface thereof into contact with or in proximity to the electrostatic latent image on the surface of the latent image carrier. In this step, particles are adhered to form a toner image (development image) on the surface of the latent 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. The image forming method of the present invention is not particularly limited with respect to the developing method.

The transfer process is a process in which the toner image formed on the surface of the latent image carrier is directly transferred to the recording medium, or the image once transferred to the intermediate transfer body is transferred again to the recording medium to form a transfer image. is there.
A corotron can be used as a transfer device for transferring the toner image from the latent image carrier to paper or the like. The corotron is effective as a means for uniformly charging the paper, but a high voltage of several kV must be applied and a high voltage power source is required in order to give a predetermined charge to the paper as a recording medium. Further, since ozone is generated by corona discharge, the rubber parts and the latent image carrier are deteriorated. Therefore, a conductive transfer roll made of an elastic material is pressed against the latent image carrier to transfer the toner image onto the paper. A contact transfer method is preferred. 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 developed image (toner image) transferred to the surface of the recording medium with a fixing device. As the fixing device, an oilless heat fixing device using a heat roll is preferably used. The heat fixing device includes a fixing roller having a heater lamp for heating inside a cylindrical metal core, 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, and the fixing roller. The pressure roller or pressure belt is disposed in pressure contact with the roller and has a heat-resistant elastic 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 the unfixed toner image is performed by inserting a recording material on which an unfixed toner image is formed between a fixing roller and a pressure roller or a pressure belt, and using a binder resin, an additive, and the like in the toner. Fix by heat melting. In the image forming method of the present invention, the fixing method is not particularly limited as long as it is oilless fixing.

  In addition, various processes such as a cleaning process for removing toner, paper dust, dust, etc. adhering to the surface of the latent image carrier by bringing a blade, brush, roll, etc. into direct contact with the surface of the latent image carrier are provided as appropriate. .

  In the image forming method of the present invention, when producing a full-color image, each of the plurality of latent image carriers has a developer carrier of each color, and the plurality of latent image carriers and developer carriers. Each color toner image is sequentially laminated on the same surface of the recording medium by a series of processes including a latent image forming process, a developing process, a transferring process, and a cleaning process, and the stacked full-color toners. An image forming method in which an image is thermally fixed in a fixing step is preferably used. By using the developer for developing an electrostatic image in the image forming method, stable development, transfer, and fixing performance can be obtained even in a tandem system suitable for, for example, miniaturization and color acceleration. .

  Examples of the recording material to which the toner image is transferred include plain paper, OHP sheet, and the like used in electrophotographic copying machines and printers. In order to further improve the smoothness of the image surface after fixing, the surface of the recording medium is preferably as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, art paper for printing Etc. can be used suitably.

  According to the image forming method of the present invention using the toner for developing an electrostatic image of the present invention, excellent releasability is maintained in oilless fixing, and there is no roll contact mark when discharging a fixed image over a long period of time. It is possible to maintain a fine image quality with excellent fixing characteristics such as excellent fixed image surface glossiness and OHP transparency.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the examples do not limit the present invention.

Examples of methods for preparing each material and methods for producing aggregated particles are shown below.
[Preparation of resin fine particles]
(1) Oil layer, styrene (manufactured by Wako Pure Chemical Industries): 30 parts by mass, n-butyl acrylate (manufactured by Wako Pure Chemical Industries): 10 parts by mass, β-carboethyl acrylate (manufactured by Rhodia Nikka): 1.4 parts by mass, acrylate: 0.25 parts by mass / dodecanethiol (manufactured by Wako Pure Chemical Industries): 0.5 parts by mass

(2) Water layer 1
-Ion exchange water: 17 parts by mass-Anionic surfactant (manufactured by Rhodia): 0.4 parts by mass

(3) Aqueous layer 2
-Ion exchange water: 40 parts by mass-Anionic surfactant (manufactured by Rhodia): 0.05 parts by mass-Ammonium persulfate (manufactured by Wako Pure Chemical Industries): 0.4 parts by mass

The above oil layer component and water layer 1 component were placed in a flask and mixed with stirring to obtain a monomer emulsified dispersion. The components of the aqueous layer 2 were put into a reaction vessel, and the inside of the vessel was sufficiently substituted with nitrogen and stirred, and then heated in an oil bath until the temperature in the reaction system reached 75 ° C. The monomer emulsion dispersion was gradually dropped into the reaction vessel over 3 hours to carry out emulsion polymerization. After completion of the dropwise addition, the polymerization was further continued at 75 ° C., and the polymerization was terminated after 3 hours.
The obtained resin fine particles were 250 nm when the number average particle diameter D _50n of the resin fine particles was measured with a laser diffraction particle size distribution measuring device (Horiba, Ltd., LA-700). A differential scanning calorimeter (Shimadzu Corporation) When the glass transition point of the resin was measured at a heating rate of 10 ° C./min using DSC-50), it was 54 ° C., and a molecular weight meter (HLC-8020, manufactured by Tosoh Corporation) was used with THF as the solvent. It was 13500 when the number average molecular weight (polystyrene conversion) was measured.
As a result, an anionic fine resin particle dispersion having a center diameter of 200 nm, a solid content of 42%, a glass transition point of 51.5 ° C., and an Mw of 29000 was obtained. Further, the SP value was calculated to be 9.37.

The SP value of the resin fine particle dispersion was calculated according to the following.
First, the monomer single SP value was calculated by the above-described formula (1), and the molar ratio of the monomer of the resin fine particles was calculated. The SP value of the entire resin fine particles was calculated from the SP value of the monomer and the molar ratio.
The SP value of the main mold release agent described later was also determined in the same manner as described above.

[Preparation of Colorant Dispersion 1]
-Cyan pigment (copper phthalocyanine B15: 3: manufactured by Dainichi Seika): 0.18 parts by mass-Ionic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0.02 parts by mass-Ion-exchanged water: 0.80 parts by mass The above components were mixed and dissolved, and dispersed with a homogenizer (IKA Ultra Tarrax) for 10 minutes to obtain a colorant dispersion having a center particle size of 168 nm.

[Preparation of inorganic fine particle dispersion]
Colloidal silica A as ST-OL (Nissan Chemical Co., Ltd.) center particle diameter of 40 nm, colloidal silica B as colloidal silica ST-OS (Nissan Chemical Co., Ltd.) center particle diameter of 8 nm, and ST-OS (Nissan Chemical Co., Ltd.) center 20 parts by weight and 40 parts by weight of a particle size of 20 nm are mixed as appropriate, 30 parts by weight of 0.3 mol / l nitric acid (HNO ₃ ) is added, 0.1 parts by weight of polyaluminum chloride is added thereto, and 20 minutes The product was allowed to stand at room temperature and agglomerated as it was.

[Preparation of release agent dispersion 1]
Polyethylene wax 1 (density 0.94, melting point 90 ° C., manufactured by Nippon Seiwa): 0.158 parts by mass Polyethylene wax 2 (density 0.91, melting point 81 ° C., manufactured by Nippon Seiwa): 0.022 parts by mass Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0.02 parts by mass Ion-exchanged water: 0.80 parts by mass The above is heated to 100 ° C. and sufficiently dispersed with IKA Ultra Tarrax T50 Thereafter, the mixture was dispersed with a pressure discharge type gorin homogenizer at 110 ° C. to obtain a wax dispersion having a center diameter of 280 nm and a solid content of 25%.
The viscosity of the main mold release agent in the E-type viscometer is 4.2 mPa · s, the complex viscosity η ^* a at a measurement frequency of 6.28 rad / s at 85 ° C. is 0.7 Pa · s, and the frequency The ratio (η ^* a / η ^* b) between the complex viscosity η ^* b and 62.8 rad / s was 1.1. The maximum endothermic peak in the suggested thermal analysis was 88 ° C., and the ratio of the endothermic area of 85 ° C. or lower was 10%. The SP value of the release agent dispersion was 9.0.

[Preparation of release agent dispersion 2]
Polyethylene wax 3 (density 0.95, melting point 100 ° C., manufactured by Nippon Seiwa): 0.161 parts by mass Polyethylene wax 4 (density 0.93, melting point 88 ° C., manufactured by Toyo Petrolite): 0.018 parts by mass Modified polyethylene wax (density 0.91, melting point 83 ° C., acid value 8 mg KOH / g, saponification value 45 mg KOH / g): 0.001 part by mass Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0. 02 parts by mass / ion-exchanged water: 0.80 parts by mass The above was heated to 115 ° C. and sufficiently dispersed with IKA Ultra Tarrax T50, and then dispersed with a pressure discharge type gorin homogenizer at 125 ° C. A wax dispersion having a diameter of 230 nm and a solid content of 25% was obtained.
The viscosity of the main mold release agent in the E-type viscometer is 4.5 mPa · s, and the complex viscosity η ^* a at a measurement frequency of 6.28 rad / s at 85 ° C. is 0.4 Pa · s. The ratio (η ^* a / η ^* b) between the complex viscosity η ^* b and 62.8 rad / s was 2.3. The maximum endothermic peak in the suggested thermal analysis was 94 ° C., and the ratio of the endothermic area of 85 ° C. or lower was 12%. The SP value of the release agent dispersion was 9.0.

[Preparation of release agent dispersion 3]
Polyethylene wax 5 (density 0.94, melting point 90 ° C., manufactured by Nippon Seiwa): 0.173 parts by mass Modified polyethylene wax (density 0.91, melting point 83 ° C., acid value 8 mgKOH / g, saponification value 45 mgKOH / g): 0.007 parts by mass. Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0.02 parts by mass. Ion exchange water: 0.80 parts by mass. After sufficiently dispersing with Thalax T50, the dispersion was treated with a pressure discharge type gorin homogenizer at 110 ° C. to obtain a wax dispersion having a center diameter of 190 nm and a solid content of 25%.
The viscosity of the main release agent in the E-type viscometer is 2.7 mPa · s, the complex viscosity η ^* a at a measurement frequency of 6.28 rad / s at 85 ° C. is 0.5 Pa · s, and the frequency The ratio (η ^* a / η ^* b) between the complex viscosity η ^* b and 62.8 rad / s was 3.2. The maximum endothermic peak in the suggested thermal analysis was 86 ° C, and the ratio of the endothermic area of 85 ° C or lower was 13%. The SP value of the release agent dispersion was 9.0.

[Preparation of release agent dispersion 4]
Polyethylene wax 6 (density 0.94, melting point 99 ° C., manufactured by Toyo Petrolite): 0.18 parts by mass Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0.02 parts by mass Ion-exchanged water: 0 .80 parts by mass The above was heated to 110 ° C. and sufficiently dispersed with IKA Ultra Tarrax T50, and then dispersed with a pressure discharge type gorin homogenizer at 120 ° C. to disperse a wax having a center diameter of 290 nm and a solid content of 25%. A liquid was obtained.
The viscosity of the release agent in an E-type viscometer is 5.4 mPa · s, the complex viscosity η ^* a at a measurement frequency of 6.28 rad / s at 85 ° C. is 1.1 Pa · s, and the frequency is 62 The ratio (η ^* a / η ^* b) between the complex viscosity η ^* b and 0.8 rad / s was 3.4. The maximum endothermic peak in the suggested thermal analysis was 99 ° C., and the ratio of the endothermic area of 85 ° C. or lower was 4%. The SP value of the release agent dispersion was 9.0.

[Preparation of release agent dispersion 5]
Polyethylene wax PW500 (density 0.93, melting point 88 ° C., manufactured by Toyo Petrolite): 0.108 parts by mass Polyethylene wax FNP0080 (density 0.91, melting point 81 ° C., manufactured by Nippon Seiwa): 0.072 parts by mass Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku): 0.02 parts by mass Ion-exchanged water: 0.80 parts by mass The above is heated to 100 ° C. and sufficiently dispersed with IKA Ultra Tarrax T50 Thereafter, the mixture was subjected to dispersion treatment at 110 ° C. with a pressure discharge type gorin homogenizer to obtain a wax dispersion having a center diameter of 200 nm and a solid content of 25%.
The viscosity of the release agent in an E-type viscometer is 1.4 mPa · s, the complex viscosity η ^* a at a measurement frequency of 6.28 rad / s at 85 ° C. is 0.1 Pa · s, and a frequency of 62 The ratio (η ^* a / η ^* b) between the complex viscosity η ^* b and 0.8 rad / s was 3.5. The maximum endothermic peak in the suggested thermal analysis was 85 ° C., and the ratio of the endothermic area at 85 ° C. or lower was 15%. The SP value of the release agent dispersion was 9.0.

[Toner Production Example 1]
-Resin fine particle dispersion: 68 parts by mass-Dispersion of Preparation 1 of colorant: 14 parts by mass-Pre-aggregate of colloidal silica A (ST-0) / colloidal silica B (ST-OL): 13.0 parts by mass -Dispersion liquid of "Preparation of mold release agent 1": 16.2 parts by mass-Polyaluminum chloride: 0.41 parts by mass The above was sufficiently mixed and dispersed in a round stainless steel flask with Ultra Turrax T50. Next, 0.36 parts by mass of polyaluminum chloride was added thereto, and the dispersion operation was continued with an ultra turrax. The flask was heated to 47 ° C. with stirring in an oil bath for heating. After maintaining at 47 ° C. for 60 minutes, 30 parts by mass of the resin dispersion was gently added thereto.

Thereafter, the pH of the system is adjusted to 6.0 with a 0.5 mol / liter sodium hydroxide aqueous solution, and then the stainless steel flask is sealed, and heated to 96 ° C. while continuing stirring using a magnetic seal. Hold 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 3 L of ion exchanged water at 40 ° C., and stirred and washed at 300 rpm for 15 minutes.
This was repeated five more times, and when the pH of the filtrate was 7.01, the electric conductivity was 9.7 μS / cm, and the surface tension was 71.2 Nm, solid-liquid separation was performed using No5A filter paper by Nutsche suction filtration. It was. Vacuum drying was then continued for 12 hours.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 5.7 μm and the particle size distribution coefficient GSD was 1.20. Further, the shape factor SF1 of the particles determined by shape observation with Luzex was 133.5, and it was observed that the particles were potato-like.

When this toner was observed with a transmission electron microscope, the shape of the release agent present in the toner was in the form of a rod and a lump, and the area ratio of the lump was 25%. Furthermore, the average diameter of the release agent was 620 nm. In addition, the presence of a shell layer (coating layer) was observed, and the thickness was 0.3 μm.
Further, the amount of the release agent on the surface of the toner was measured by X-ray photoelectron spectroscopic analysis and found to be 13 atm%.

The toner outermost surface was quantified using XPS (X-ray photoelectron spectroscopy). Specifically, the raw material (resin, wax, surfactant, etc.) used for toner granulation and the carbon atom C _1s spectrum of the outermost surface of the toner were measured under the following measurement conditions.
Next, curve fitting processing is performed on the spectrum of the toner based on the principle of the least square method for the peak position of each of the raw materials and the area intensity ratio of the spectrum (the basic algorithm uses the Gauss-Newton method). Thus, the composition ratio of each raw material on the outermost surface of the toner was quantified.

-Measurement conditions by XPS-
-X-ray photoelectron spectrometer: JPS-9000MX manufactured by JEOL Ltd.
Photoelectron excitation: MgKα ray (10 kV, 30 mA)
-Pass energy of photoelectron energy analyzer: 30V

[Toner Production Example 2]
Resin fine particle dispersion: 91 parts by mass, “Dispersant preparation 2” dispersion: 21 parts by mass, held at 47 ° C. for 60 minutes, and then slowly adding 25 parts by mass of the resin dispersion to be added Were operated in the same manner as in “Toner Production Example 1”.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 5.6 μm and the particle size distribution coefficient GSD was 1.21. In addition, the particle shape factor SF1 obtained by shape observation with Luzex was 132.8, and it was observed that the particles were potato-like.

When this toner was observed with a transmission electron microscope, the shape of the release agent present in the toner was a stick and a lump, and the area ratio of the lump was 28%. Furthermore, the average diameter of the release agent was 750 nm. The presence of a shell layer (coating layer) was observed and the thickness was 0.2 μm.
Further, the amount of the release agent on the surface of the toner was measured by X-ray photoelectron spectroscopic analysis and found to be 18 atm%.

[Toner Production Example 3]
The same operation as in “Toner Production Example 2” was carried out except that the resin fine particle dispersion was 112 parts by mass and the dispersion of “Release Agent Preparation 3” was 19 parts by mass.
When the particle diameter at this time was measured, the volume average diameter D50 was 5.8 μm, and the particle size distribution coefficient GSD was 1.22. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 133.0, and it was observed that the particles were potato-like.

When this toner was observed with a transmission electron microscope, the shape of the release agent present in the toner was in the form of a rod and a lump, and the area ratio of the lump was 25%. Furthermore, the average diameter of the release agent was 310 nm. The presence of a shell layer (coating layer) was observed and the thickness was 0.2 μm.
Further, the amount of the surface release agent of the toner was measured by X-ray photoelectron spectroscopic analysis and found to be 24 atm%.

[Toner Production Example 4]
Resin fine particle dispersion: 100 parts by weight, “Partitioner Preparation 4” dispersion: 25 parts by weight, held at 47 ° C. for 60 minutes, and then the resin fine particle dispersion was not added. The same operation as in Production Example 1 was performed.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 5.4 μm and the particle size distribution coefficient GSD was 1.21. Further, the shape factor SF1 of the particles determined by shape observation with Luzex was 129.5, and it was observed that the particles were potato-like.

When this toner was observed with a transmission electron microscope, the shape of the release agent present in the toner was a stick and a lump, and the area ratio of the lump was 11%. Furthermore, the average diameter of the release agent was 1560 nm. Further, the presence of a shell layer (coating layer) was observed, and the thickness thereof was 0.05 μm.
Further, the amount of the surface release agent on the toner was measured by X-ray photoelectron spectroscopic analysis and found to be 35 atm%.

[Toner Production Example 5]
Resin fine particle dispersion: 76 parts by mass, “Partitioner Preparation 6” dispersion: 44 parts by mass, and addition of resin fine particle dispersion at 47 ° C. was 31 parts by mass. The same operation as in “2” was performed.
When the particle diameter at this time was measured with a Coulter counter, the volume average diameter D50 was 5.6 μm and the particle size distribution coefficient GSD was 1.23. Further, the shape factor SF1 of the particles obtained by shape observation with Luzex was 128.9, and it was observed that the particles were potato-like.

When this toner was observed with a transmission electron microscope, the shape of the release agent present in the toner was a stick and a lump, and the area ratio of the lump was 15%. Furthermore, the average diameter of the release agent was 1600 nm. Further, the presence of a shell layer (coating layer) was observed, and the thickness thereof was 0.5 μm.
Further, when the amount of the surface release agent of the toner was measured by X-ray photoelectron spectroscopy, it was 7 atm%.

[Preparation of developer for developing electrostatic image]
Hydrophobic silica (TS720: manufactured by Cabot) was added to 50 g of the produced toner, and blended in a sample mill. This is weighed so that the toner concentration is 5% with respect to a ferrite carrier having an average particle diameter of 50 μm coated with 1% of methacrylate (manufactured by Soken Chemical Co., Ltd.), stirred and mixed for 5 minutes by a ball mill, and used for electrostatic charge image development. A developer was prepared.

[Example 1]
The toner fixability of “Toner Production Example 1” is set to 13.0 g / m ² using a modified Docu Center Color 400 machine (hereinafter, may be abbreviated as “DCC400 modified machine”) manufactured by Fuji Xerox Co., Ltd. After adjustment and printing, the image was fixed using an external fixing device at a fixing speed of 180 mm / sec under a Nip width of 6.5 mm.

  The fixing device had good peelability, and it was confirmed that the fixing device was peeled without any resistance, and no offset occurred. Also, no image defect was observed when the fixed image was folded in two and stretched again. Furthermore, the surface glossiness of these fixed images was good, the transparency of the OHP sheet was excellent, and a transmission image without turbidity was confirmed.

[Example 2]
After adjusting the toner applied amount to 13.0 g / m ² using the DCC400 toner remodeling machine of “Toner Production Example 2”, using an external fixing device, the Nip width is 6.5 mm, the fixing speed is 180 mm / Fixed in sec.

  The fixing device had good peelability, and it was confirmed that the fixing device was peeled off without any resistance, and no offset was generated. Also, no image defect was observed when the fixed image was folded in two and stretched again. Further, the surface gloss of these fixed images was good, the transparency of the OHP sheet was excellent, and a transmission image without turbidity was confirmed.

Example 3
After adjusting the toner fixability of “Toner Production Example 3” to a toner loading of 13.0 g / m ² using a DCC400 remodeling machine, fixing was performed using an external fixing device with a Nip width of 6.5 mm. Fixing was performed at a speed of 180 mm / sec.

  The fixing device had good peeling properties, and it was confirmed that the fixing device was peeled off without any resistance, and no offset occurred significantly. In addition, very small image defects were observed when the fixed image was folded in two and stretched again. Furthermore, the surface glossiness of these fixed images was good, the transparency of the OHP sheet was excellent, and a transmission image without turbidity was confirmed.

[Comparative Example 1]
After adjusting the toner fixability of “Toner Production Example 4” to a toner loading of 13.0 g / m ² using a DCC400 remodeling machine, the image was fixed using an external fixing device with a Nip width of 6.5 mm. Fixing was performed at a speed of 180 mm / sec.

  The releasability at this fixing device was poor, and the image roughness due to the separation failure from the roll occurred remarkably during discharge. Further, contact marks such as pinch rolls at the time of discharge were also observed remarkably. Further, the surface glossiness of these fixed images was poor due to roughness, and the roll contact trace was also visually recognized on the OHP sheet, and the image quality was low.

[Comparative Example 2]
After adjusting the toner fixability of “Toner Production Example 5” to a toner loading of 13.0 g / m ² using a DCC400 remodeling machine, fixing was performed using an external fixing device with a Nip width of 6.5 mm. Fixing was performed at a speed of 180 mm / sec.

  The releasability at this fixing device was poor, and the image roughness due to the separation failure from the roll occurred remarkably during discharge. In addition, the contact mark such as a pinch roll at the time of discharge was so severe that the image roughness could not be determined. Further, the surface glossiness of these fixed images was poor due to roughness, and the roll contact trace was also visually recognized on the OHP sheet, and the image quality was low.

  Table 1 below shows the material design and evaluation results of Examples 1 to 3 and Comparative Examples 1 and 2.

From the results shown in Table 1, in Comparative Example 1 which does not contain a trace amount of release agent, problems were observed in all aspects from peel resistance to OHP permeability. Further, in Comparative Example 2, since the content of the trace release agent exceeded the predetermined value, the amount of the main release agent was relatively decreased and its function was impaired. There was a problem.
On the other hand, in Examples 1 to 3 in which the main mold release agent and the minute mold release agent had a predetermined density difference and mixing ratio, good results were obtained in all evaluation items.

  In Example 1, resin fine particles having an SP value of 9.5 were produced by increasing the blending ratio of styrene and decreasing the blending of n-butyl acrylate in the resin fine particle dispersion used for producing the toner. Then, a developer for developing an electrostatic image was prepared. At that time, the difference in SP value between the resin fine particle dispersion and the main release agent was 0.5. This developer was fixed in the same manner as in Example 1. Even in the case where the SP value of the resin fine particle dispersion is 9.4 or less (Example 1) and the above 9.5, good results were obtained in all the evaluation items, but in the case of 9.4 or less, In particular, the image gloss, roll mark, and OHP permeability were good.

Claims (4)

An electrostatic charge developing toner comprising at least a binder resin, a colorant, and two or more release agents,
Of the two or more types of release agents, the difference in density between the main release agent and the trace release agent having a smaller content than the main release agent is a value specified by ASTM D792, and is set to 0. 02 or more,
The toner for developing an electrostatic charge image, wherein a total mixing ratio of the trace release agent in the release agent is 0.1 to 15.0% by mass. At least a resin fine particle dispersion in which resin fine particles of 1 μm or less are dispersed is mixed with a colorant dispersion and a release agent dispersion, and an aggregating agent is added thereto to prepare an aggregated particle dispersion in which aggregated particles are dispersed. A method for producing an electrostatic charge image developing toner comprising an aggregating step comprising:
The difference in density between the main mold release agent contained in the mold release agent dispersion and the micro mold release agent having a smaller content than the main mold release agent is a value specified by ASTM D792, and is 0.02 or more. And
After the aggregation step, including a fusion and coalescence step of fusing and coalescing by heating to a temperature above the glass transition point of the resin fine particles,
Finally, the method for producing a toner for developing electrostatic charge, wherein the total mixing ratio of the trace release agent in the release agent in the toner is 0.1 to 15.0% by mass.   An electrostatic charge image developing developer comprising the electrostatic charge image developing toner according to claim 1. A latent image forming step of forming a latent image on the latent image carrier, a developing step of developing the latent image using an electrostatic charge image developing toner on the developer carrier, and the developed image after development are covered. An image forming method comprising: a transfer step of transferring to a recording body; and a fixing step of fixing the developed image transferred to the recording body,
The electrostatic charge image developing toner is the electrostatic charge image developing toner according to claim 1,
An image forming method, wherein the fixing in the fixing step is oilless fixing.