JP5115020B2 - Method for producing toner for developing electrostatic image, and method for cleaning toner for developing electrostatic image - Google Patents

Description

The present invention relates to a method for producing electrostatic charge image developing toner over to a method of cleaning toner 及 BiShizu charge image developing.

  A method of visualizing image information through an electrostatic charge image such as electrophotography is currently used in various fields. In conventional electrophotography, an electrostatic latent image is formed on a photosensitive member or an electrostatic recording member by using various means, and electro-sensitive fine particles called toner are adhered to the electrostatic latent image. Generally, a method of visualizing through a plurality of steps of developing an image (toner image), transferring it to the surface of a transfer medium, and fixing it by heating or the like is generally used.

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

  In recent years, with the increasing demand for energy saving necessary for image formation, in order to save power in the fixing process, which occupies a certain amount of power, and to expand fixing conditions, the toner fixing temperature must be increased. It is necessary to lower the temperature. By lowering the toner fixing temperature, in addition to the power saving and the expansion of the fixing conditions, the waiting time until the fixing temperature on the surface of the fixing member such as a fixing roll at the time of power input, that is, the so-called warm-up time is shortened. There are significant advantages such as a longer time and longer life of the fixing member.

  On the other hand, with the progress of the advanced information society in recent years, there is an increasing demand for providing information documents constructed by various methods with higher quality images. In order to realize a higher-definition image in color image formation, there is a demand for a toner having a smaller particle size, a narrow particle size distribution and shape distribution, and excellent charging characteristics. At the same time, there is a demand for images with high gloss such as photographic quality and high storage stability.

  By the way, the toner production methods are roughly classified into a conventional dry-type melt-kneading pulverization method and a wet-type method in which the toner is granulated in a liquid. Wet methods are being evaluated from the standpoints of reducing the toner diameter, sharpening the particle size distribution, freedom of shape control, reducing the energy cost of production, and the like. In the wet method, since it is necessary to remove impurities after the toner particles are produced, for example, the conductivity of water in which the toner manufactured in the wet method is redispersed is set to 1 to 100 μS / cm, or manufactured in the wet method. It has been proposed that the chargeability of the toner under high temperature and high humidity is improved by reducing the amount of alkali metal or alkaline earth metal remaining in the toner to 5 wt% or less (for example, Patent Documents). 1 and Patent Document 2).

Further, the total ion amount of Na ions, K ions, Ca ions, Mg ions and NH ₄ ions in the dispersion liquid in which the toner is dispersed in water is 0.5 μmol value / g or more and 7.5 μmol value / g or less. It has been proposed to pay attention (for example, see Patent Document 3).
Further, it has been proposed to use a styrene / acrylic resin as the resin and evaluate the ion abundance ratio in the dispersion by ESCA measurement (for example, Patent Document 4 and Patent Document 5).
JP-A-7-319205 Japanese Patent Laid-Open No. 9-218532 JP 2000-330330 A JP-A-9-114125 JP 2001-255700 A

An object of the present invention is to solve the following problems. That is, the object of the present invention is to realize a high-gloss image with small particle size, excellent particle size distribution, excellent low-temperature fixability and image storability, and suppressed development fog, and better chargeability and thermal storage. process for producing a toner over the electrostatic image developing to achieve both gender is to provide a method of cleaning contact and toner.

The above problem is solved by the following means. That is, the present invention
<1> A step of obtaining a toner containing at least a polyester resin having an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less by a wet method, and dispersing the obtained toner in an aqueous medium. When the initial Na ion amount (a) in the toner dispersion is 50 ppm or less, the initial Na ion amount (a) and the Na ion amount (b) in the toner dispersion after 24 hours of dispersion are difference (b-a) until a 20ppm or less, have a cleaning step of cleaning the toner, the cleaning process, pH 4 and step, the toner for cleaning the toner pH9 above pH10 by the following processing solution After the following, the process of washing with an ion exchange resin while treating with ultrasonic waves, and the step of washing the toner with ion exchange water, It is a manufacturing method.
< 2 > When at least an acid value of 5 mg KOH / g or more and 25 mg KOH / g or less of a polyester resin, a colorant, and a release agent is dispersed in a water-based medium, the toner produced by a wet method is
The initial Na ion amount (a) in the toner dispersion is 50 ppm or less, and the difference between the initial Na ion amount (a) and the Na ion amount (b) in the toner dispersion after dispersion for 24 hours ( b-a) until a 20ppm or less, it has a cleaning step of cleaning the toner, the cleaning step, a step of washing the toner pH9 above pH10 by the following treatment solution was the toner to pH4 or less A method for cleaning a toner for developing an electrostatic charge image , comprising: a step of washing with an ion exchange resin while processing with ultrasonic waves; and a step of washing the toner with ion exchange water .

According to the present invention, a small particle size, excellent particle size distribution, excellent low-temperature fixability and image storability, a highly glossy image with suppressed development fog, and further excellent chargeability and heat storage properties are achieved. method for producing electrostatic charge image developing toner over to both, it is possible to provide a method of cleaning contact and toner.

Hereinafter, embodiments of the present invention will be described in detail.
<Toner for electrostatic image development>
The electrostatic charge image developing toner according to the embodiment (hereinafter sometimes simply referred to as “toner”) includes at least a polyester resin having an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less, a colorant, and a release agent . In addition, when the toner produced by a wet method is dispersed in an aqueous medium, the initial Na ion amount (a) in the toner dispersion is 50 ppm or less, and the initial Na ion amount (a) is 24 hours. The difference (ba) from the Na ion amount (b) in the toner dispersion after dispersion is 20 ppm or less.
The toner according to the embodiment has the above-described configuration, realizes a high-gloss image with a small particle size, excellent particle size distribution, excellent low-temperature fixability and image storage stability, and suppressed development fog. It is possible to achieve both good charging properties and heat storage properties. The reason for this is not clear, but is thought to be due to the following reasons.

In addition to low-temperature fixability, chargeability, and image glossiness, image storage properties such as fixed image strength due to affinity with paper improve, so use a polyester resin with a predetermined acid value as a binder resin for toner. Is preferred. In addition, since it is easy to control the particle size and shape of the toner, a wet method is suitable for producing a toner having a small particle size and an excellent particle size distribution. In particular, in the case of the emulsion aggregation method, it is preferable to use a resin having a predetermined acid value from the viewpoint of improving granulation properties such as particle stability in water.
However, since a polyester resin having a predetermined acid value has, for example, a carboxylic acid that easily binds to Na ions, when a toner containing the polyester resin is manufactured by a wet method, it is added in the manufacturing process. Na ions (compounds containing Na) bind to the carboxylic acid of the polyester resin. It is considered that Na ions bonded to the carboxylic acid penetrate into the toner. If this Na ion remains in the toner, the resistance to the toner or the vicinity of the toner surface is reduced due to the influence of moisture under high humidity, so that the chargeability deteriorates and tends to cause development fog.

Therefore, by controlling the amount of Na ions when the toner is dispersed in the aqueous medium within the above range, it is possible to prevent the charging property from deteriorating. Therefore, even if the toner contains a polyester having a predetermined acid value, it is possible to suppress a decrease in chargeability, to be hardly affected by moisture even under high humidity, and to prevent development fog. It is done.
From the above, the toner according to the embodiment realizes a high gloss image with a small particle size, excellent particle size distribution and suppressed development fog, and has excellent low-temperature fixability, image storability and heat storage property. However, it is considered that good chargeability can be expressed.

First, the configuration of the toner according to the embodiment will be described.
As described above, the toner according to the embodiment includes a polyester resin and a colorant. In addition, the toner according to the embodiment may contain other additives as necessary.

-Polyester resin-
The polyester resin according to the embodiment is obtained mainly by, for example, polycondensation of polyvalent carboxylic acids and polyhydric alcohols.
Examples of the polyvalent carboxylic acid include terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid, and other aromatic carboxylic acids; maleic anhydride, fumaric acid, succinic acid, Examples thereof include aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and one or more of these polyvalent carboxylic acids can be used.
Among these polycarboxylic acids, aromatic carboxylic acids are preferably used, and trivalent or higher carboxylic acids (trimellitic acid) together with dicarboxylic acids to form a crosslinked structure or a branched structure in order to ensure good fixing properties. And acid anhydrides thereof) are preferably used in combination.

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

  The glass transition temperature (hereinafter sometimes abbreviated as “Tg”) of the polyester resin is preferably 40 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 70 ° C. or lower. If the Tg is higher than 80 ° C., it cannot be fixed at a sufficiently low temperature as compared with the prior art. On the other hand, if Tg is lower than 40 ° C., sufficient heat storage property cannot be obtained, and storage stability of a fixed image is not sufficient.

Furthermore, the polyester resin used in the toner according to the embodiment needs to have an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less. If it is 5 mgKOH / g or more, the toner has good affinity for paper and good chargeability. Further, when a toner is produced by the emulsion aggregation method described later, it is easy to produce emulsion particles, and it is possible to suppress the aggregation speed in the aggregation process of the emulsion aggregation process and the shape change speed in the coalescence process from being significantly increased. Therefore, it is easy to perform particle size control and shape control. Further, if the acid value of the polyester resin is within 25 mgKOH / g, the environmental dependency of charging is not adversely affected, and the aggregation speed in the aggregation process in the toner production by the emulsion aggregation method and the shape change in the coalescence process. Since the speed is remarkably slow, it is possible to prevent the productivity from being lowered.
The acid value of the polyester resin is preferably 6 mgKOH / g or more and 23 mgKOH / g or less.

  The polyester resin is preferably a crystalline polyester resin. Since the crystalline polyester resin is compatible with the amorphous polyester resin when melted, the viscosity of the toner is remarkably lowered, so that a toner having better low-temperature fixability and image gloss can be obtained. Of the crystalline polyester resins, aromatic crystalline resins are generally higher than the melting point range described later, and are preferably aliphatic crystalline polyester resins.

The crystalline polyester has excellent low-temperature fixability as described above, but on the other hand, it deteriorates the chargeability, so that it is usually difficult to use a large amount of crystalline polyester in the toner. Furthermore, the presence of Na ions bonded to the carboxylic acid contained in the crystalline polyester resin causes a further decrease in the charge amount. However, it is possible to reduce the amount of Na ions when the toner according to the embodiment is dispersed in the aqueous medium, and to suppress a decrease in charge amount due to the presence of Na ions. For this reason, even if the toner contains more crystalline polyester resin than in the past, the charge amount can be maintained.
Therefore, the content of the crystalline polyester resin in the toner according to the embodiment is preferably 2% by mass or more and 30% by mass or less, and more preferably 4% by mass or more and 25% by mass or less. If the content is 2% by mass or more, the viscosity of the amorphous polyester resin can be sufficiently lowered at the time of melting, and an improvement in low-temperature fixability is easily obtained. On the other hand, if the amount is 30% by mass or less, the charging property of the toner due to the presence of the crystalline polyester resin can be prevented from being deteriorated, so that the image strength after fixing on the recording medium can be easily obtained.

  The melting point of the crystalline polyester resin is preferably in the range of 50 ° C. or higher and 100 ° C. or lower, preferably in the range of 55 ° C. or higher and 95 ° C. or lower, and more preferably in the range of 60 ° C. or higher and 90 ° C. or lower. . If the melting point is 50 ° C. or higher, the storage stability of the toner and the storage stability of the toner image after fixing are good, and if it is 100 ° C. or lower, the low temperature fixability is easily improved.

  The “crystalline polyester resin” according to the embodiment is not a stepwise endothermic change but a clear change in differential scanning calorimetry (hereinafter sometimes abbreviated as “DSC”). It has an endothermic peak. The crystalline polyester resin is a polymer obtained by copolymerizing other components with respect to the main chain. When the other components are 50% by mass or less, the copolymer is also called crystalline polyester.

  The crystalline polyester resin is synthesized from an acid (dicarboxylic acid) component and an alcohol (diol) component. In the following, the “acid-derived constituent component” refers to a polyester resin before the synthesis of the polyester resin. Refers to a component that was an acid component, and “alcohol-derived component” refers to a component that was an alcohol component before the synthesis of the polyester resin.

[Acid-derived components]
Examples of the acid to be the acid-derived constituent component include various dicarboxylic acids, but the acid-derived constituent component in the crystalline polyester resin according to the embodiment is preferably a linear aliphatic dicarboxylic acid.
For example, succinic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,11-undecanedicarboxylic acid Acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc., or lower alkyl esters thereof, An acid anhydride may be mentioned, but not limited thereto. Among these, adipic acid, sebacic acid, and 1,10-decanedicarboxylic acid are preferable in consideration of availability.

  As the acid-derived constituent component, other constituent components such as a dicarboxylic acid-derived constituent component having a double bond and a dicarboxylic acid-derived constituent component having a sulfonic acid group may be contained.

  In the present specification, “constituent mol%” means that the acid-derived constituent component in the entire acid-derived constituent component in the polyester resin or the alcohol constituent component in the entire alcohol-derived constituent component is 1 unit (mol). ) Indicates the percentage.

[Alcohol-derived components]
As the alcohol for becoming an alcohol component, an aliphatic diol is desirable. For example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-dodecanediol, 1,12-undecanediol, 1,13-tridecanediol, Examples include, but are not limited to, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosanediol, and the like. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferable in view of availability and cost.

  The molecular weight (weight average molecular weight; Mw) of the crystalline polyester resin is preferably 8,000 or more and 40,000 or less from the viewpoint of resin manufacturability, fine dispersion during toner production, and compatible toner during melting, More preferably, it is 10,000 or more and 30,000 or less. If it is 8,000 or more, the resistance reduction of the crystalline polyester resin can be suppressed, so that the charging property can be prevented from decreasing. If it is 40,000 or less, the cost of resin synthesis is suppressed, and the low-temperature fixability is not adversely affected in order to prevent a decrease in sharp melt properties.

  In the embodiment, the molecular weight of the polyester resin was measured and calculated by GPC (Gel Permeation Chromatography). Specifically, HPC-8120 manufactured by Tosoh Corporation was used for GPC, TSKgel SuperHM-M (15 cm) manufactured by Tosoh Corporation was used for the column, and the polyester resin was measured with a THF solvent. Next, the molecular weight of the polyester resin was calculated using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample.

(Production method of polyester resin)
There is no restriction | limiting in particular as a manufacturing method of a polyester resin, It can manufacture with the general polyester polymerization method which makes an acid component and an alcohol component react. For example, direct polycondensation, transesterification, and the like are used depending on the type of monomer. The molar ratio (acid component / alcohol component) at the time of reacting the acid component with the alcohol component varies depending on the reaction conditions and the like, and thus cannot be generally described. However, in order to increase the molecular weight, it is usually 1/1. The degree is preferred.

  Catalysts that can be used in the production of the polyester resin include alkali metal compounds such as sodium and lithium; alkaline earth metal compounds such as magnesium and calcium; metal compounds such as zinc, manganese, antimony, titanium, tin, zirconium, and germanium; Examples thereof include phosphorous acid compounds; phosphoric acid compounds; and amine compounds.

  In addition to the polyester resin, other resins may be used in combination as the binder resin. Other resins include: ethylene resins such as polyethylene and polypropylene; styrene resins such as polystyrene and α-polymethylstyrene; (meth) acrylic resins such as polymethyl methacrylate and polyacrylonitrile; polyamide resins and polycarbonate resins; Examples include polyether resins and copolymer resins thereof.

-Colorant-
The toner according to the embodiment includes a colorant. The colorant may be a dye or a pigment, but is preferably a pigment from the viewpoint of light resistance and water resistance.
For example, carbon black, aniline black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, dupont oil red, quinoline yellow, methylene blue chloride, phthalocyanine blue, malachite green oxalate, lamp black, rose bengal, quinacridone, benzy Thin Yellow, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 185, C.I. I. Pigment red 238, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 74, C.I. I. Pigment blue 15: 1, C.I. I. A known pigment such as CI Pigment Blue 15: 3 can be used.

In the toner for developing an electrostatic charge image of the exemplary embodiment, the content of the colorant is preferably 1 part by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the binder resin.
It is also effective to use a colorant that has been surface-treated as necessary, or a pigment dispersant. By appropriately selecting the type of the colorant, yellow toner, magenta toner, cyan toner, black toner and the like can be obtained.

-Release agent-
The toner according to the embodiment may contain a release agent as necessary. Examples of the release agent include paraffin wax such as low molecular weight polypropylene and low molecular weight polyethylene; silicone resin; rosins; rice wax; carnauba wax; The melting point of these release agents is preferably 50 ° C. or higher and 100 ° C. or lower, and more preferably 60 ° C. or higher and 95 ° C. or lower.
The content of the release agent in the toner is desirably 0.5% by mass or more and 15% by mass or less, and more desirably 1.0% by mass or more and 12% by mass or less. If the content of the release agent is 0.5% by mass or more, it is possible to prevent a peeling failure particularly in the case of oilless fixing. If the content of the release agent is 15% by mass or less, deterioration of toner fluidity can be prevented, so that image quality and reliability of image formation can be maintained.

-Other additives-
In addition to the above-described components, various components such as an internal additive, a charge control agent, inorganic powder (inorganic fine particles), and organic fine particles may be added to the toner in the exemplary embodiment as necessary. it can.

  Examples of the internal additive include metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and magnetic materials such as compounds containing these metals.

  Examples of the charge control agent include quaternary ammonium salt compounds, nigrosine compounds, dyes composed of complexes of aluminum, iron, chromium, and triphenylmethane pigments.

  The inorganic fine particles are added for various purposes, but may be added for adjusting the viscoelasticity of the toner. By adjusting the viscoelasticity, it is possible to adjust the image glossiness and the penetration into the paper. As the inorganic fine particles, known inorganic fine particles such as silica fine particles, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, or those obtained by hydrophobizing the surface thereof can be used alone or in combination of two or more. However, silica fine particles having a refractive index smaller than that of the binder resin are preferably used from the viewpoint that transparency such as color developability and OHP permeability is not impaired. Further, the silica fine particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, silicone oil or the like are preferably used.

[Toner characteristics]
Furthermore, the toner according to the embodiment preferably has a spherical shape with a shape factor SF1 in the range of 115 to 140.
As for the shape of the toner, a spherical toner is advantageous in terms of developability and transferability, but it may be inferior to an indeterminate shape in terms of cleaning properties. When the toner has a shape in the above-described range, transfer efficiency and image density can be improved, high-quality image formation can be performed, and the surface of the photoreceptor can be improved.
The shape factor SF1 is more preferably in the range of 120 to 138.

Here, the shape factor SF1 is obtained by the following equation (1).
SF1 = (ML ² / A) × (π / 4) × 100 (1)
In the above formula (1), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.

  Further, the volume average particle size of the toner according to the exemplary embodiment is desirably 3 μm or more and 9 μm or less, more desirably 3.5 μm or more and 8.5 μm or less, and further desirably 4 μm or more and 8 μm or less. If the volume average particle diameter is 3 μm or more, a decrease in toner fluidity can be suppressed, and the chargeability of each particle can be easily maintained. In addition, the charge distribution does not spread, preventing fogging on the background and preventing toner from spilling from the developer. Further, when the volume average particle diameter of the toner is 3 μm or more, the cleaning property is improved. If the volume average particle size is 9 μm or less, a decrease in resolution can be suppressed, so that a sufficient image quality can be obtained and the recent demand for high image quality can be satisfied.

Incidentally, the volume average particle diameter D ₅₀ is, for example, Coulter Counter TAII, Multisizer II - in (Beckman Coulter) the measured particle size ranges which are divided based on the particle size distribution measuring apparatus such as a (channel) On the other hand, a cumulative distribution is drawn from the smaller diameter side for each volume and number, and the particle size that is 16% cumulative is the volume D _16v and number D _16P , and the particle size that is 50% cumulative is the volume D _50v , number D _50P , and cumulative 84 % Particle size is defined as volume D _84v and number D _84P . Using these, the volume average particle size distribution index (GSDv) is calculated as ( _D84v / _D16V ) ^1/2 .

  The SF1 is quantified mainly by analyzing a microscope image or a scanning electron microscope (SEM) image using an image analyzer, and can be calculated as follows, for example. That is, an optical microscope image of higher alcohol particles dispersed on the surface of the slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length and projected area of 100 particles are obtained, calculated by the above equation (1), and the average Obtained by determining the value.

<Method for producing toner for developing electrostatic charge>
The toner for developing an electrostatic latent image according to the embodiment is obtained by wet-processing a toner containing at least a polyester resin having an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less, and the obtained toner is water-based. When dispersed in a medium, the initial Na ion amount (a) in the toner dispersion is 50 ppm or less, and the initial Na ion amount (a) and Na ions in the toner dispersion after 24 hours of dispersion It is manufactured by washing the toner until the difference (b−a) from the amount (b) is 20 ppm or less.
Examples of the wet method include a melt suspension method, an emulsion aggregation method, a dissolution suspension method, and the like.

The emulsion aggregation method is a method of preparing dispersions (emulsion liquid, pigment dispersion liquid, etc.) each containing components (binder resin, colorant, etc.) contained in the toner, and mixing these dispersion liquids to combine the toner components. In this method, aggregated particles are produced by agglomeration, and then the aggregated particles are heated to the melting point or glass transition temperature of the binder resin or higher to thermally fuse the aggregated particles.
The emulsion aggregation method makes it easier to produce toner with a smaller particle size and has a narrower particle size distribution compared to the dry kneading and pulverization method and other wet methods such as the melt suspension method and the dissolution suspension method. Easy to obtain. Further, the shape control is easier than in the melt suspension method, the dissolution suspension method, and the like, and a uniform amorphous toner can be produced. Furthermore, it is possible to control the structure of the toner, such as film formation, and when it contains a release agent or crystalline polyester resin, the surface exposure of these can be suppressed, thus preventing deterioration of chargeability and storage stability. can do.

Next, the manufacturing process of the emulsion aggregation method will be described in detail.
In the emulsion aggregation method, at least an emulsification step of emulsifying a raw material constituting the toner to form resin particles (emulsion particles), an aggregation step of forming aggregates of the resin particles, and a fusion step of fusing the aggregates And have. Hereinafter, an example of a toner manufacturing process using an emulsion aggregation method will be described for each process.

-Emulsification process-
Examples of the method for preparing the emulsion include a phase inversion emulsification method and a melt emulsification method.
In the phase inversion emulsification method, a resin to be dispersed is dissolved in a hydrophobic organic solvent in which the resin is soluble, and a base is added to the organic continuous phase (Oil phase; O) to neutralize it. Thereafter, by introducing an aqueous medium (Water phase; W), the water in oil (W / O) system is changed to an oil in water (O / W) system, so that the resin present in the organic continuous phase Phase into a discontinuous phase. As a result, the resin can be dispersed and stabilized in the form of particles in the aqueous medium to prepare an emulsion.
In the melt emulsification method, an emulsified liquid can be prepared by applying a shearing force to a solution obtained by mixing an aqueous medium and a resin with a disperser. At that time, particles can be formed by heating to lower the viscosity of the resin component. In addition, a dispersant may be used to stabilize the dispersed resin particles. Furthermore, if the resin is oily and has a relatively low solubility in water, dissolve the resin in a solvent and disperse the particles together with the dispersant and polymer electrolyte in water, and then heat or reduce the pressure. By evaporating the solvent, an emulsion in which the resin particles are dispersed can be prepared.

  Examples of the disperser used for dispersion of the emulsion by the melt emulsification method include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser.

  Examples of the aqueous medium include water such as distilled water and ion-exchanged water; alcohols; and the like.

  Examples of the dispersant used in the emulsification step include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate; sodium dodecylbenzenesulfonate. Anionic surfactants such as sodium octadecyl sulfate, sodium oleate, sodium laurate, potassium stearate, cationic surfactants such as laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, lauryldimethylamine oxide, etc. Zwitterionic surfactant, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Surfactants such as nonionic surfactants down alkylamines, and the like. Among these, anionic surfactants are generally used from the viewpoint of easy cleaning and environmental suitability.

  The content of the resin particles contained in the emulsified liquid in the emulsification step is preferably in the range of 10% by mass to 50% by mass, and more preferably in the range of 20% by mass to 40% by mass. When the content is 10% by mass or more, the particle size distribution is not excessively widened, and deterioration of toner characteristics can be prevented. On the other hand, if the amount is 50% by mass or less, uniform stirring can be performed, and a toner having a narrow particle size distribution and uniform characteristics can be obtained.

  The size of the resin particles is preferably in the range of 0.08 μm or more and 0.8 μm or less, more preferably 0.09 μm or more and 0.6 μm or less in terms of the average particle diameter (volume average particle diameter), and 0.10 μm or more and 0.00. 5 μm or less is more desirable. If it is 0.08 μm or more, the resin particles tend to aggregate. On the other hand, when the particle size is 0.8 μm or less, the particle size distribution of the toner is difficult to spread, and precipitation of the emulsified particles can be suppressed.

Before entering the aggregating step described below, it is preferable to prepare a dispersion liquid in which a colorant, a release agent, and the like, which are toner components other than the binder resin, are dispersed.
In addition to the method of preparing a dispersion corresponding to each component such as a binder resin and a colorant, for example, when preparing an emulsion of a certain component, other components may be added to the solvent to add two or more The components may be emulsified at the same time so that the dispersed particles contain a plurality of components.

-Aggregation process-
In the aggregation step, the dispersion of the crystalline resin particles obtained in the emulsification step, the dispersion of the amorphous resin particles, and the colorant dispersion are mixed to obtain a mixed solution, and the glass transition temperature of the polyester resin. Aggregate by heating at the following temperature to form aggregated particles. Aggregated particles are formed by making the pH of the mixed solution acidic while stirring. As pH, the range of 2-7 is desirable, The range of 2.2-6 is more desirable, The range of 2.4-5 is further more desirable.

  It is also effective to use a flocculant when forming the agglomerated particles. As the aggregating agent, a surfactant having a polarity opposite to that of the surfactant used for the dispersant, an inorganic metal salt, and a divalent or higher metal complex can be suitably used. In particular, the use of a metal complex is particularly desirable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

  Examples of the inorganic metal salt include metal salts such as calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and polyaluminum chloride, polyaluminum hydroxide, and calcium polysulfide. Examples thereof include inorganic metal salt polymers. Of these, aluminum salts and polymers thereof are particularly preferred. In order to obtain a sharper particle size distribution, the valence of the inorganic metal salt is bivalent than monovalent, trivalent than bivalent, trivalent than trivalent, and tetravalent than trivalent. The inorganic metal salt polymer is more suitable.

  Further, when the aggregated particles have a desired particle size, a toner having a structure in which the surface of the core aggregated particles is coated with a binder resin may be prepared by additionally adding resin emulsified particles. In this case, the release agent and the polyester resin are difficult to be exposed on the toner surface, which is desirable from the viewpoints of chargeability and storage stability. In the case of additional addition, a flocculant may be added or pH adjustment may be performed before additional addition.

-Fusion process-
In the fusing step, the agglomeration is stopped by raising the pH of the suspension of the agglomerated particles to a range of 4 to 8 under the stirring conditions in accordance with the agglomeration step, and the glass transition temperature of the binder resin or higher. The aggregated particles are fused by heating at a temperature of. An aqueous NaOH solution is preferred as the alkaline solution used to raise the pH. Other alkaline solutions such as an ammonia solution are not preferable from the viewpoints of volatility and safety. In addition, since a divalent alkaline solution such as Ca (OH) ₂ is difficult to dissolve in water, the amount added is increased and the ability to stop aggregation may not be sufficient.

  The heating time may be as long as the fusion is performed, and is preferably 0.5 hours or more and 10 hours or less. Cooling is performed after the aggregated particles are fused to obtain fused particles. Also, in the cooling process, the cooling rate is increased in the vicinity of the melting point of the mold release agent and polyester resin (melting point ± 10 ° C range), so-called rapid cooling suppresses recrystallization of the mold release agent and polyester resin. Exposure may be suppressed.

  Through the above steps, a toner can be obtained as fused particles. The fused particles (toner) obtained by fusing need to be washed through a solid-liquid separation process such as filtration, as will be described later.

-Washing process-
When the toner (the fused particles) obtained by the wet method as described above is dispersed in an aqueous medium, the initial Na ion amount (a) in the toner dispersion is 50 ppm or less, and the initial Na ion amount The difference (b−a) between (a) and the amount of Na ions (b) in the toner dispersion after 24 hours of dispersion must be 20 ppm or less.

  Here, the “initial Na ion amount” refers to a filtrate obtained by filtering a part of the toner dispersion 3 minutes after the toner is dispersed in an aqueous medium 20 times the toner solid content. The measured value.

Further, “the amount of Na ions in the toner dispersion after 24 hours of dispersion” refers to a filtrate obtained by filtering a part of the toner dispersion 24 hours after the toner is dispersed in the medium. The value measured for. Hereinafter, “the amount of Na ions in the toner dispersion after 24 hours of dispersion” is appropriately referred to as “the amount of Na ions after 24 hours of dispersion”.
The aqueous medium used when measuring the initial Na ion amount is ion exchanged water at 30 ° C. containing 1.0% of polyvinyl alcohol having an Mw of 500 or more and 1000 or less.

  The amount of Na ions refers to a value obtained by measurement with an ion chromatograph. The ion chromatograph uses Tosoh Corporation IC-2001, Tosoh Corporation TSKgel IC-Cation, TSK guard column IC-C column, eluent of 2 mmol / l NaCl aqueous solution, flow rate; 1.2 ml / Min, temperature: 25 ° C., sample concentration: 5 mg / 5 ml Under the conditions of 5 mg / 5 ml, the amount of Na ion is measured using the electric conductivity method as a detection method.

The toner obtained in the fusing process has an initial Na ion amount (a) in the toner dispersion of 50 ppm or less, and the initial Na ion amount (a) and Na ions in the toner dispersion after 24 hours of dispersion. In order to wash until the difference (b−a) from the amount (b) becomes 20 ppm or less, the toner washing step includes a step of washing the toner with a treatment liquid having a pH of 9 or more and a pH of 10 or less; After the following, it is preferable to carry out washing by a washing step including a step of washing with an ion exchange resin while treating with ultrasonic waves and a step of washing the toner with ion exchange water.
Hereinafter, the toner cleaning step will be described by dividing it into the above steps.

[Step of washing with treatment liquid of pH 9 or more and pH 10 or less]
First, the toner obtained in the fusing step is washed with a treatment liquid having a pH of 9 or more and a pH of 10 or less. Specifically, the toner is dispersed in ion-exchanged water, adjusted to pH 9 to 10 at a temperature of 20 ° C. or higher and 40 ° C. or lower, and washed with stirring.
If the temperature is 20 ° C. or higher, the detergency does not deteriorate. If the temperature is 40 ° C. or lower, the toner surface can be prevented from being rough. If the pH is 9 or more, the carboxylic acid is sufficiently dissociated and the adsorbed surfactant can be removed. In addition, it is more preferable to use an aluminum-based flocculant because it is easy to remove the bound surfactant due to a change in aluminum ions. A pH of 10 or less is preferable because hydrolysis hardly occurs.

  Next, the toner and the liquid are solid-liquid separated from the toner dispersion. Thereafter, the toner is further dispersed in ion exchange water at 30 ° C. and stirred with a mechanical stirrer. The step of re-dispersing in water after the solid-liquid separation and stirring is repeated until the conductivity in the toner dispersion becomes 100 μS or less.

[Step of washing with ion exchange resin while treating with ultrasonic waves after adjusting to pH 4 or lower]
Thereafter, in order to wash the toner with a treatment liquid having a pH of 4 or less, the toner dispersion is adjusted to a pH of 4 or less and stirred with a mechanical stirrer.
By adjusting the toner dispersion to pH 4 or lower, the dissociation of the carboxylic acid is suppressed, and the surfactant bonded to the metal ions bonded to the carboxylic acid, particularly Na ions, or ions derived from the aggregating agent is removed. be able to. Thereafter, ultrasonic waves are applied to the dispersion, and the ion exchange resin is added while dispersing.
When the dissociation of the carboxylic acid is suppressed, the dispersion stability of the particles in water is reduced and the particles are aggregated. Therefore, it is preferable to crush the aggregated particles using ultrasonic waves. When the agglomerated particles are not crushed, the inside of the agglomerated particles may not be sufficiently washed, and the chargeability may become non-uniform. This operation may be repeated as necessary. Further, since the ions near the toner surface are also precipitated in the water by the ultrasonic wave, the cleaning effect is further improved. Furthermore, by adding an ion exchange resin in such a state, it is possible to efficiently remove Na ions.

The ultrasonic condition is preferably 28 kHz or more and 100 kHz or less, and more preferably 35 kHz or more and 80 kHz or less. If it is less than 28 kHz, sufficient crushing / cleaning effect may not be obtained, and if it is more than 100 kHz, the toner particles may be destroyed. The ultrasonic time is preferably 3 minutes to 60 minutes, more preferably 5 minutes to 45 minutes. If the time is less than 3 minutes, sufficient crushing / cleaning effects may not be obtained. If the time is longer than 60 minutes, the toner particles may be destroyed.
As the ion exchange resin, a cation exchange resin capable of replacing Na is preferable. As the ion exchange resin, known resins can be used. The addition amount of the ion exchange resin is preferably 3 to 20 parts by mass with respect to 100 parts by mass of the toner.

[Step of washing with ion exchange water]
Next, the toner that has undergone the above-described [step of washing with ion exchange resin while being treated with ultrasonic waves after being adjusted to pH 4 or lower] is subjected to solid-liquid separation. The operation of dispersing the toner in 30 ° C. ion-exchanged water, stirring with a mechanical stirrer, and solid-liquid separation is repeated.

  [Step of washing with a treatment solution of pH 9 or more and pH 10 or less], [Step of washing with ion exchange resin while treating with ultrasonic waves after adjusting to pH 4 or less] and [Step of washing with ion exchange water] Washing is performed until the amount of Na ions contained in the filtrate is 50 ppm or less after passing through a series of steps or by repeating the above three steps. In addition, each step may be performed a plurality of times, for example, after [step of washing with a treatment liquid having a pH of 9 or more and pH 10 or less] is performed a plurality of times, and after the pH is adjusted to 4 or less, the ions are treated with ultrasonic waves The step of washing with an exchange resin] and the step of washing with ion-exchanged water may be performed, or the step of washing with a treatment solution having a pH of 9 or more and pH 10 or less, and the pH is adjusted to 4 or less, followed by ultrasonic treatment. However, after performing the step of washing with an ion exchange resin, the step of washing with ion exchange water may be performed a plurality of times.

  Further, after the toner dispersion liquid in which the Na ion amount contained in the filtrate is 50 ppm or less is allowed to stand for 24 hours with stirring, the increase in the Na ion amount contained in the filtrate is 20 ppm or less. is important.

  In addition, when the increase amount of the Na ion amount after being allowed to stand for 24 hours exceeds 20 ppm, the above [step of washing with ion exchange resin while reducing the pH to 4 or less and then treating with ultrasonic waves] and [ It can be improved by repeating the step of washing with ion-exchanged water.

  As described above, when a toner using a polyester resin as a binder resin is manufactured by a wet method, the carboxylic acid exists in the toner because the polyester resin has carboxylic acid. Therefore, it is considered that Na ions bonded at the toner production stage exist to some extent.

  Therefore, if the Na ion amount (initial Na ion amount) of the filtrate of the toner dispersion is 50 ppm or more, the initial charge amount is greatly reduced due to the influence of moisture at high temperature and high humidity. It is considered that environmental dependency is large and causes problems such as developing fog. Furthermore, if the amount of increase in Na ion (the amount of Na ion after 24 hours of dispersion) after the toner dispersion having an initial Na ion content of 50 ppm or less is left for 24 hours is 20 ppm or more, the toner dispersion is left at high temperature and high humidity. It is considered that the amount of charge is lowered due to the influence of moisture gradually penetrating into the toner, causing fogging at the beginning of development after being left.

  Therefore, by reducing the initial Na ion amount of the toner dispersion and the difference between the initial Na ion amount of the toner dispersion and the Na ion amount after 24 hours of dispersion, the toner may contain a polyester resin having a predetermined acid value. Therefore, it is possible to maintain the charge amount of the toner at a preferable value.

  The initial sodium ion amount is preferably 45 ppm or less, and more preferably 40 ppm or less. The difference (b−a) between the initial sodium ion amount (a) and the Na ion amount (b) after 24 hours of dispersion is preferably 18 ppm or less, more preferably 15 ppm or less.

  After the toner cleaning, the solid-liquid separated toner is dried with a freeze vacuum dryer, a shelf dryer, a hot air dryer or the like. The moisture content of the toner after drying is preferably 1.5% by mass or less, and more preferably 1.2% by mass or less.

(External additive)
In the embodiment, an external additive such as a fluidizing agent or an auxiliary agent may be added to the toner particle surface. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Of these, at least two or more types of external additives are used, and at least one of the external additives is an average primary particle in the range of 30 nm to 200 nm, and further in the range of 30 nm to 180 nm. It preferably has a diameter.

  By reducing the particle size of the toner, non-electrostatic adhesion to the photosensitive member increases, which may cause transfer defects and image loss of fine lines and cause transfer unevenness such as superimposed images. The transferability can be improved by adding a large external additive having an average primary particle size of 30 nm to 200 nm.

  If the average primary particle size is smaller than 30 nm, the initial toner fluidity is good, but the non-electrostatic adhesion between the toner and the photoreceptor cannot be sufficiently reduced, and the transfer efficiency is lowered and the image This may cause a blur or deteriorate the uniformity of the image. Further, the fine particles are embedded in the toner surface due to stress in the developing device over time, and the chargeability changes, causing problems such as a decrease in copy density and fogging on the background. When the average primary particle size is larger than 200 nm, it is easy to be detached from the toner surface and also causes deterioration of fluidity.

<Developer for developing electrostatic image>
The toner for developing an electrostatic charge image in this embodiment is used as it is as a one-component developer or as a two-component developer. When used as a two-component developer, it is used by mixing with a carrier.

  There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. Examples thereof include magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin coating layer on the surface of the core material, and magnetic dispersion carriers. Further, a resin-dispersed carrier in which a conductive material 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 thereof include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, epoxy resins and the like.

  Examples of the conductive material 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. It is not limited.

  Examples of the core material of the carrier 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, it is a magnetic material. It is preferable. The volume average particle size of the core material of the carrier is generally in the range of 10 μm to 500 μm, and preferably in the range of 30 μm to 100 μm.

  In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution prepared by dissolving the coating resin and, if necessary, various additives in an appropriate solvent. 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 an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. A fluidized bed method in which the coating layer forming solution is sprayed in a state of being suspended by the above, a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater, and the solvent is removed.

  The mixing ratio (mass ratio) of the toner of this embodiment and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 or more and 30: 100 or less, and 3: 100 or more and 20: 100. The following range is more preferable.

<Image forming apparatus>
Next, an image forming apparatus according to an embodiment using the electrostatic image developing toner according to the embodiment will be described.
An image forming apparatus according to an embodiment includes an image carrier, a developing unit that develops an electrostatic charge image formed on the image carrier as a toner image with a developer, and a toner image formed on the image carrier. And a fixing means for fixing the toner image transferred onto the transfer body, and using the electrostatic charge image developer according to the embodiment as the developer. It is.

In this image forming apparatus, for example, the part including the developing unit may have a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus main body. As the process cartridge, a developer holding body is used. The process cartridge according to the embodiment that includes at least the electrostatic image developer according to the embodiment is preferably used.
Hereinafter, an example of an image forming apparatus according to an embodiment will be described as an embodiment, but the present invention is not limited to this. The main parts shown in the figure will be described, and the description of the other parts will be omitted.

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

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

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

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

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

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

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

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

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

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

  Thereafter, the recording paper P is sent to a fixing device (fixing means) 28, where the toner image is heated, and the color-superposed toner image is melted and fixed on the recording paper P.

Examples of the transfer target to which the toner image is transferred include plain paper and OHP sheet used for electrophotographic copying machines, printers, and the like.
In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the transfer target is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with a resin or the like, for printing Art paper or the like can be suitably used.

  Further, it is preferable that the image glossiness (75 °) after fixing of a monochrome image composed of cyan, magenta, and yellow having an image area ratio of 100% is 50% or more. In a full-color image, it is desirable that the image gloss is high from the viewpoint of color development and photographic image quality reproducibility. When using highly glossy paper such as coated paper for higher image quality, if the image gloss is significantly lower than the gloss of the paper, it will appear visually dark, so the fixed image will be less than the gloss of the paper. High gloss is more preferable. For example, when fixing is performed using coated paper such as coated paper having a glossiness (75 °) of 50% or more, the image glossiness after fixing is desirably 50% or more, and more desirably 60% or more. The measurement can be performed based on JIS Z 8741.

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

<Process cartridge, toner cartridge>
FIG. 2 is a schematic configuration diagram showing an example of a preferred example of a process cartridge for containing an electrostatic charge image developer according to the embodiment. In the process cartridge 200, a charging roller 108, a developing device 111, a photoconductor cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure are combined using a mounting rail 116 together with the photoconductor 107. , And integrated.
The process cartridge 200 is detachable from an image forming apparatus main body including a transfer device 112, a fixing device 115, and other components (not shown). It forms a forming apparatus.

  The process cartridge 200 shown in FIG. 2 includes a charging device 108, a developing device 111, a cleaning device 113, an opening 118 for exposure, and an opening 117 for static elimination exposure. Can be combined. In the process cartridge of this embodiment, in addition to the photoconductor 107, the charging device 108, the developing device 111, the cleaning device (cleaning means) 113, the opening 118 for exposure, and the opening 117 for static elimination exposure. At least one selected from the group consisting of:

  Next, the toner cartridge according to the embodiment will be described. The toner cartridge according to the embodiment is detachably attached to the image forming apparatus, and at least the toner cartridge that stores toner to be supplied to the developing unit provided in the image forming apparatus is described above. It is a toner according to the embodiment. Note that the toner cartridge according to the embodiment only needs to contain at least toner, and may contain developer, for example, depending on the mechanism of the image forming apparatus.

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

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

  EXAMPLES Hereinafter, although an Example and a comparative example are given and embodiment is described in detail in detail, this invention is not limited to a following example. Unless otherwise specified, “part” is based on mass.

[Measuring method]
<Measurement method of volume average particle diameter (when the particle diameter to be measured is 2 μm or more)>
When the diameter of the particles to be measured was 2 μm or more, the volume average particle diameter of the particles was measured using a Coulter Multisizer-II type (manufactured by Beckman-Coulter). As the electrolytic solution, ISOTON-II (manufactured by Beckman-Coulter) was used.

  As a measurement method, 0.5 mg of a measurement sample was added to 2 ml of a 5% aqueous solution of a surfactant (sodium dodecylbenzenesulfonate) as a dispersant, and this was added to 100 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size is 2.0 to 2.0 using the Coulter Multisizer-II aperture with an aperture diameter of 100 μm. The particle size distribution of particles in the range of 60 μm was measured. The number of particles measured is 50,000.

  For the measured particle size distribution, a cumulative distribution was drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size at 50% cumulative was defined as the volume average particle size.

<Measurement method of volume average particle diameter (when the particle diameter to be measured is less than 2 μm)
When the particle diameter to be measured was less than 2 μm, the volume average particle diameter of the particles was measured using a laser diffraction particle size distribution analyzer (LA-700: manufactured by Horiba, Ltd.).

  As a measuring method, the sample in the state of dispersion is adjusted so as to have a solid content of about 2 g, and ion exchange water is added thereto to make about 40 ml. This was put into the cell until an appropriate concentration was reached, waited for 2 minutes, and measured when the concentration in the cell became almost stable.

  The volume average particle diameter of each obtained channel was accumulated from the smaller volume average particle diameter, and the volume average particle diameter was determined to be 50%.

  When measuring powder, 2 g of a measurement sample is added to 50 ml of a 5% aqueous solution of a surfactant (sodium dodecylbenzenesulfonate), and dispersed for 2 minutes with an ultrasonic disperser (1,000 Hz). A sample was prepared and measured by the same method as the above-mentioned dispersion.

<Measurement of toner particle size distribution>
For the measurement of the particle size distribution index of the toner, a cumulative distribution is drawn from the small diameter side for each of the volume and number of the particle size range (channel) obtained by dividing the particle size distribution measured using the Coulter Multisizer-II type, Volume average particle diameter D _16V , cumulative average 16%, number average particle diameter D _16P , volume average particle diameter D _50V , cumulative 50%, number average particle diameter D _50p , volume average particle diameter D _84V , cumulative 84%, The number average particle diameter D is defined as _84p . Using these, the volume average particle size distribution index (GSD _v ) is determined from (D _84V / D _16V ) 0.5, and the number average particle size distribution index (GSD _p ) is _calculated from (D _84p / D _16p ) 0.5. The lower number average particle size distribution index (below GSD _p ) was calculated from (D _16P / D _50P ).

<Calculation of shape factor SF1>
The toner shape factor SF1 is analyzed using a scanning electron microscope (SEM) (S-4800 manufactured by Hitachi High-Technologies Corp.) and the SEM image using a Luzex image analyzer (FT manufactured by Nireco Corporation). And was calculated as follows. That is, an optical microscope image of higher alcohol (C ₁₈ H ₃₇ OH) particles dispersed on the surface of a slide glass is taken into a Luzex image analyzer through a video camera, and the maximum length (ML) and projected area (A) of 100 toner particles. Was calculated by applying to the following formula, and the average value was defined as the toner shape factor SF1.
SF1 = (ML ² / A) × (π / 4) × 100

<Measuring method of melting point and glass transition point>
The glass transition point (Tg) and the melting point are measured from 0 ° C. to 150 ° C. under a temperature rising rate of 10 ° C./min using a differential scanning calorimeter (manufactured by Mac Science: DSC3110, thermal analysis system 001). As a result, a DSC spectrum was obtained.

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) (polystyrene conversion) of the polyester resin was measured using GPC (Tosoh Co., Ltd .: HLC-8120 made). The column used was Tosoh TSKgel SuperHM-M (15 cm), and the GPC spectrum was measured with a THF solvent. The molecular weight of the polyester resin was calculated using a molecular weight calibration curve created with a monodisperse polystyrene standard sample.

<Measurement of acid value>
The acid value was measured according to JIS K0070 and using a neutralization titration method. That is, an appropriate amount of a sample is taken, 100 ml of a solvent (diethyl ether / ethanol mixed solution) and a few drops of an indicator (phenolphthalein solution) are added, and shaken sufficiently until the sample is completely dissolved in a water bath. This was titrated with a 0.1 mol / l potassium hydroxide ethanol solution, and the end point was when the indicator was light red for 30 seconds. When the acid value is A, the sample amount is S (g), the 0.1 mol / l potassium hydroxide ethanol solution used for the titration is B (ml), and f is the factor of the 0.1 mol / l potassium hydroxide ethanol solution. , A = (B × f × 5.611) / S.

<Measurement of Na ion content>
The amount of Na ions in the filtrate of the toner dispersion was measured under the following conditions by ion chromatography (IC-2001, manufactured by Tosoh Corporation).
Column: TSKgel IC-Cation, TSK guard column IC-C (manufactured by Tosoh Corporation)
・ Eluent: 2 mmol / l NaCl aqueous solution ・ Flow rate: 1.2 ml / min
・ Temperature: 25 ℃
・ Detection method: Electric conductivity ・ Sample concentration: 5 mg / 5 ml

<Measurement of conductivity>
The conductivity of the toner dispersion liquid filtrate was measured at 25 ° C. using a conductivity meter CM-30S manufactured by Toa Denpa Kogyo Co., Ltd.

<PH measurement>
To measure the pH of the toner dispersion filtrate, a pH meter (HM-26S) manufactured by Toa Denpa Kogyo Co., Ltd. was used at 25 ° C.

(Synthesis of non-crystalline polyester resin (1))
In a heat-dried two-necked flask, 80 mol parts of polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, 10 mol parts of ethylene glycol, 10 mol parts of cyclohexanediol, and terephthalic acid After 80 parts by mole, 10 parts by mole of isophthalic acid, and 10 parts by mole of n-dodecenyl succinic acid, dibutyltin oxide is added as a catalyst, nitrogen gas is introduced into the container, and the temperature is raised in an inert atmosphere. A copolycondensation reaction was performed at 150 to 230 ° C. for about 12 hours, and then the pressure was gradually reduced at 210 to 250 ° C. to synthesize an amorphous polyester resin (1).

  The weight average molecular weight (Mw) of the obtained amorphous polyester resin (1) was 17,200. The acid value of the amorphous polyester resin (1) was 12.4 mgKOH / g.

Furthermore, the melting point of the non-crystalline polyester resin (1) was measured using a differential scanning calorimeter (DSC) and analyzed according to JIS standards (see JIS K-7121).
As a result, a stepwise endothermic change was observed without showing a clear peak. The glass transition temperature (Tg) at the midpoint of the stepwise endothermic change was 59 ° C.

(Synthesis of non-crystalline polyester resin (2))
In a heat-dried two-necked flask, 90 mol parts of polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane, 10 mol parts of ethylene glycol, 80 mol parts of terephthalic acid, and isophthalic acid An amorphous polyester resin (2) was synthesized in the same manner as the amorphous polyester resin (1) except that 20 mol parts were used as a raw material.

When the molecular weight was measured in the same manner as in the amorphous polyester resin (1), the weight average molecular weight (Mw) of the obtained amorphous polyester resin (2) was 16,200.
The acid value of the amorphous polyester resin (2) was 18.2 mgKOH / g.

  When the melting point measurement was performed in the same manner as in the non-crystalline polyester resin (1) and the DSC spectrum was obtained, no clear peak was shown, and a step-like endothermic change was observed. The glass transition temperature (Tg) at the midpoint of the stepwise endothermic change was 62 ° C.

(Synthesis of non-crystalline polyester resin (3))
At the end of the reaction of the amorphous polyester resin (1), 2.6 mol parts of dimethyl terephthalate was added to modify the terminal of the resin, thereby synthesizing the amorphous polyester resin (3).

When the molecular weight was measured in the same manner as in the amorphous polyester resin (1), the weight average molecular weight (Mw) of the obtained amorphous polyester resin (3) was 18,400.
The acid value of the amorphous polyester resin (3) was 2.2 mgKOH / g.

  When the melting point measurement was performed in the same manner as in the non-crystalline polyester resin (1) and the DSC spectrum was obtained, no clear peak was shown, and a step-like endothermic change was observed. The glass transition temperature (Tg) at the midpoint of the stepwise endothermic change was 60 ° C.

(Synthesis of non-crystalline polyester resin (4))
At the end of the reaction of the amorphous polyester resin (1), 2.6 mol parts of 1,2,4 trimellitic acid was added to modify the terminal of the resin to synthesize the amorphous polyester resin (4).

When the molecular weight was measured in the same manner as in the amorphous polyester resin (1), the weight average molecular weight (Mw) of the obtained amorphous polyester resin (4) was 20,400.
The acid value of the amorphous polyester resin (4) was 32.4 mgKOH / g.

When the melting point measurement was performed in the same manner as in the non-crystalline polyester resin (1) and the DSC spectrum was obtained, no clear peak was shown, and a step-like endothermic change was observed. The glass transition temperature (Tg) at the midpoint of the stepwise endothermic change was 62 ° C.

(Synthesis of crystalline polyester resin (1))
In a heat-dried three-necked flask, 43.4 parts by mass of dimethyl sebacate, 32.8 parts by mass of 1,10-decanediol, 27 parts by mass of dimethyl sulfoxide, 0.03 parts by mass of dibutyltin oxide as a catalyst, Then, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and stirred at 180 ° C. for 4 hours with mechanical stirring. Dimethyl sulfoxide was distilled off under reduced pressure, and then the temperature was gradually raised to 220 ° C. under reduced pressure, stirred for 1.5 hours, air-cooled when it became viscous, the reaction was stopped, and aliphatic 65 parts by mass of a crystalline polyester resin (1) was synthesized.

When the molecular weight was measured in the same manner as for the amorphous polyester resin (1), the resulting aliphatic crystalline polyester resin (1) had a weight average molecular weight (Mw) of 15,400.
Further, the melting point measurement was performed in the same manner as the non-crystalline polyester resin (1), and the DSC spectrum was obtained. As a result, the aliphatic crystalline polyester resin (1) had a clear peak, and the melting point (Tm1) was 76 ° C. Met.

  Table 1 below shows the weight average molecular weight (Mw), glass transition temperature or melting point, and acid value of the non-crystalline polyester resin and the crystalline polyester resin.

(Amorphous polyester resin dispersion (1))
Prepare 160 parts of an amorphous polyester resin (1), 233 parts of ethyl acetate, and 0.1 part of an aqueous sodium hydroxide solution (0.3N), and put them in a 500 ml separable flask at 70 ° C. The mixture was heated and stirred with a three-one motor (Shinto Kagaku Co., Ltd.) to prepare a resin mixture. While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added to effect phase inversion emulsification, and the solvent was removed to obtain an amorphous polyester resin dispersion (1).
The volume average particle diameter of the resin particles in the amorphous polyester resin dispersion (1) was 200 nm, and the solid content was 30%.

(Amorphous polyester resin dispersion (2))
An amorphous polyester resin dispersion (2) was obtained in the same manner as the amorphous polyester resin dispersion (1). The volume average particle diameter of the resin particles in the amorphous polyester resin dispersion (2) was 180 nm, and the solid content was 30%.

(Amorphous polyester resin dispersion (3))
An amorphous polyester resin dispersion (3) was obtained in the same manner as the amorphous polyester resin dispersion (1). The volume average particle diameter of the resin particles in the amorphous polyester resin dispersion (3) was 480 nm, the particle size distribution was broad, and coarse powder was present. The solid content was 30%.

(Amorphous polyester resin dispersion (4))
An amorphous polyester resin dispersion (4) was obtained in the same manner as the amorphous polyester resin dispersion (1). The volume average particle diameter of the resin particles in the amorphous polyester resin dispersion (4) was 100 nm, and the solid content was 30%.

(Crystalline polyester resin dispersion (1))
Prepare 160 parts of crystalline polyester resin (1), 233 parts of ethyl acetate, and 0.1 part of aqueous sodium hydroxide (0.3N), put them in a 500 ml separable flask and heat at 70 ° C. The mixture was stirred with a three-one motor (manufactured by Shinto Kagaku Co., Ltd.) to prepare a resin mixture. While further stirring this resin mixture, 373 parts of ion-exchanged water was gradually added to carry out phase inversion emulsification, and the solvent was removed to obtain a crystalline polyester resin dispersion (1).

  The volume average particle size of the resin particles in the crystalline polyester resin dispersion (1) was 170 nm, and the solid content was 30%.

(Release agent dispersion)
Paraffin wax (Nippon Seiwa Co., Ltd., HNP-9, melting point: 75 ° C.): 50 parts Anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen RK): 0.5 parts Exchanged water: 200 parts or more were mixed, heated to 95 ° C., and dispersed using a homogenizer (manufactured by IKA, Ultra Turrax T50). Thereafter, a dispersion treatment (solid content concentration: 20%) in which the release agent was dispersed was prepared by dispersing with a Manton Gorin high-pressure homogenizer (Gorin). The volume average particle size of the release agent was 0.23 μm.

(Colorant dispersion)
・ Cyan pigment (Daiichi Seika Co., Ltd., Pigment Blue 15: 3 (copper phthalocyanine))
1000 parts, anionic surfactant (Daiichi Kogyo Seiyaku Co., Ltd., Neogen R) 15 parts, ion exchange water 9000 parts or more are mixed, dissolved, and high-pressure impact disperser Ultimateizer (Sugino Machine Co., Ltd., HJP30006) ) For about 1 hour to prepare a colorant dispersion liquid in which a colorant (cyan pigment) is dispersed. The volume average particle size of the colorant (cyan pigment) in the colorant dispersion was 0.16 μm, and the solid content concentration was 20%.

Example 1
(Manufacture of toner (1))
・ Crystalline polyester resin dispersion (1) 26.7 parts ・ Amorphous polyester resin dispersion (1) 267 parts ・ Colorant dispersion 25 parts ・ Releasing agent dispersion 40 parts ・ Anionic surfactant (TeycaPower) ) 2.0 parts-emulsification process-
The raw material was placed in a 2 L cylindrical stainless steel container, and the homogenizer (Ultra Larax T50, manufactured by IKA) was used, and the homogenizer was rotated at 4000 rpm and dispersed and mixed for 10 minutes while applying a shearing force. Next, 1.75 parts of a 10% nitric acid aqueous solution of polyaluminum chloride as a flocculant was gradually added dropwise, and the homogenizer was rotated at 5000 rpm for 15 minutes and mixed to obtain a raw material dispersion.

-Aggregation process-
Thereafter, the raw material dispersion was transferred to a polymerization kettle equipped with a stirrer and a thermometer and started to be heated with a mantle heater to promote the growth of aggregated particles at 42 ° C. At this time, the pH of the raw material dispersion was adjusted to a range of 3.2 or more and 3.8 or less using 0.3N nitric acid or 1N sodium hydroxide aqueous solution. The raw material dispersion was kept in the above pH range and allowed to stand for about 2 hours to form aggregated particles. The volume average particle diameter of the aggregated particles was 5.4 μm.

-Fusion process-
Next, 100 parts of the amorphous polyester resin dispersion (1) was additionally added to the raw material dispersion, and the resin particles of the amorphous polyester resin (1) were adhered to the surface of the aggregated particles. Further, the temperature of the raw material dispersion was raised to 44 ° C., and aggregated particles were prepared while confirming the size and form of the particles using an optical microscope and Multisizer II. Thereafter, in order to fuse the aggregated particles, an aqueous NaOH solution was added dropwise to the raw material dispersion to adjust the pH to 7.5, and then the raw material dispersion was heated to 95 ° C. Thereafter, the raw material dispersion was allowed to stand for 3 hours to fuse the aggregated particles. After confirming that the aggregated particles were fused with an optical microscope, the raw material dispersion was cooled at a temperature decrease rate of 1.0 ° C./min.

-Washing process-
[Step of washing with treatment liquid of pH 9 or more and pH 10 or less]
Thereafter, using 0.3N nitric acid or 1N aqueous sodium hydroxide solution, the raw material dispersion was adjusted to pH 9.5 at 25 ° C., stirred for 20 minutes, and sieved with a mesh having a pore diameter of 20 μm. Next, the raw material dispersion was filtered. The toner after the solid-liquid separation was dispersed in ion-exchanged water at 30 ° C., which is 20 times the amount of the solid content of the toner, and stirred for 20 minutes for filtration.
This process was repeated three times and it was confirmed that the filtrate had a conductivity of 34 μS.

[Step of washing with ion exchange resin while treating with ultrasonic waves after adjusting to pH 4 or lower]
Thereafter, the toner is redispersed in ion exchange water at 30 ° C., which is 20 times the solid amount of the toner, and 5 parts by mass of ion exchange resin is added to 100 parts by mass of the toner. Washing was performed for 10 minutes while applying a frequency of 45 kHz using an electronic company: W-115T. At this time, when the pH of the system did not become 4 or less, adjustment was performed by adding 0.3 N nitric acid. Thereafter, filtration was performed.

[Step of washing with ion exchange water]
After repeating the step of washing with a treatment solution having a pH of 9 or more and pH 10 or less and the step of washing with an ion exchange resin while being treated with ultrasonic waves after being adjusted to pH 4 or less in Example 1 above, It was re-dispersed in 30 ° C. ion-exchanged water of 20 times the solid amount of toner and washed three times with water.

  [Step of washing with a treatment solution having a pH of 9 or more and pH 10 or less], [Step of washing with an ion exchange resin while being treated with ultrasonic waves after being adjusted to pH 4 or less], and [Ion-exchange water] A series of washing in the step of washing] is referred to as “washing (1)”.

-Toner drying-
After the cleaning (1) was completed, the toner particles (1) were obtained by drying with a freeze vacuum dryer.
The obtained toner particles (1) had a volume average particle size distribution index GSD _v of 1.21, a number average particle size distribution index GSD _p of 1.25, and a volume average particle diameter of 6.2 μm. The shape factor SF1 obtained by image analysis was 128.

<Initial Na ion amount in toner dispersion (a)>
Toner 3 minutes after the obtained toner particles (1) were redispersed in 30 ° C. ion-exchanged water containing 1.0% polyvinyl alcohol in 20 times the amount of toner solids A part of the dispersion was filtered, and the filtrate conductivity (hereinafter referred to as “initial conductivity”) was measured and found to be 8 μS. Moreover, it was 12 ppm when the amount of Na ions (initial Na ion amount) of this filtrate was quantified using an ion chromatograph.

<Na ion amount in toner dispersion after dispersion for 24 hours (b)>
The dispersion was then left stirring for 24 hours. The dispersion after 24 hours was filtered, and the conductivity of the filtrate (hereinafter referred to as “conductivity after 24 hours of dispersion”) was measured and found to be 10 μS. Similarly, the amount of Na ions in the filtrate (the amount of Na ions after 24 hours of dispersion) was measured and found to be 16 ppm.

  To 100 parts of the toner particles after the washing (1), silica particles having a primary particle size of 40 nm subjected to surface hydrophobization treatment (made by Nippon Aerosil Co., Ltd., hydrophobic silica: RX50) 1.0% as an external additive Then, 1.0 part of metatitanic acid compound particles having an average primary particle diameter of 20 nm, which is a reaction product obtained by treating 40 parts of isobutyltrimethoxysilane and 10 parts of trifluoropropyltrimethoxysilane to 100 parts of metatitanic acid, Mix for 5 minutes with a Henschel mixer. Further, the toner (1) was obtained by passing through an ultrasonic vibration sieve (Dalton).

(Career)
Ferrite particles (average particle size: 35 μm) 100 parts Toluene 14 parts Perfluoroacrylate copolymer (critical surface tension 24 mN / m) 1.6 parts Carbon black (“VXC-72” manufactured by Cabot Corporation, resistance 100 Ωcm Less than)
0.12 parts cross-linked melamine resin particles (average particle size; 0.3 μm, toluene insoluble) 0.3 parts Carbon black diluted with toluene and dispersed in a perfluoroacrylate copolymer using a sand mill, Furthermore, it stirred with the stirrer for 10 minutes and prepared the film layer forming liquid. Next, this coating layer forming solution and ferrite particles are put into a vacuum degassing type kneader and stirred at a temperature of 60 ° C. for 30 minutes, and then the pressure is reduced to distill off toluene, thereby forming a resin coating layer and carrier. Obtained.

<Evaluation of toner>
(Heat storage)
As a sample, the toner (1) was allowed to stand in an environment of 55 ° C./50% RH for 24 hours, and then the thermal storage property was evaluated.
Using a powder tester (manufactured by Hosokawa Micron Corporation), 20 g of the above sample weighed accurately is put on a 53 μm sieve, vibrated for 90 seconds with an amplitude of 1 mm, and the toner mass on each sieve after vibration was measured. The index of thermal storage was calculated as a percentage of the sample mass (20 g). The measurement was performed in an environment of 25 ° C./50% RH. In this evaluation, if the index of the heat storage property after vibration is 40 or less, it can be used without any problem in practice, and more preferably 30 or less.

(Chargeability)
36 g of toner (1) and 414 g of the carrier were put in a 2 L V blender, stirred for 20 minutes, and then sieved with a mesh having a pore size of 212 μm to prepare developer (1).

  The obtained developer (1) was charged into a developer of DocuPrint C2220 (Fuji Xerox Co., Ltd.) and seasoned for 24 hours in a low temperature and low humidity environment (10 ° C./15% RH). Thereafter, the developing machine was spun for 3 minutes under the same environment, and the charge amount of the developer was measured using a blow-off charge amount measuring device (TB200, manufactured by Toshiba Corporation) under low temperature and low humidity.

Next, the developer (1) was filled in a developer of DocuPrint C2220 (Fuji Xerox Co., Ltd.) and seasoned for 24 hours in an environment of high temperature and high humidity (28 ° C./85% RH). Thereafter, the developing machine is idled for 3 minutes in the same environment, and the charge amount of the developer is charged with a blow-off charge amount measuring device (TB200, manufactured by Toshiba Corporation) under high temperature and high humidity (initial charge amount). Was measured.
Furthermore, the developing device was mounted on the actual machine as it was, and drawing was performed to evaluate the fog. For the evaluation of the fog, the image copied again was visually observed, and the fog of the non-image area (initial fog) was graded and evaluated from the following viewpoints. Up to G2 can be used.
G1: No fogging is observed at all in the non-image area.
G2: Although a slight fog is observed in the non-image area, it is a level with no problem.
G3: Fog is scattered in the non-image area, and there is a risk of hindering repeated use.
G4: The fog spreads over the entire non-image area.
G5: The fog spreads as a whole regardless of whether it is an image portion or a non-image portion, which is a level outside the problem.

Next, the actual machine was allowed to stand for 1 week under high temperature and high humidity, and the charge amount of the developer after that was measured using a blow-off charge amount measuring device (manufactured by Toshiba Corporation). . Furthermore, the developing device was attached to the actual machine, and the fogging (fogging after being left) was evaluated by performing picture drawing.
Table 2 shows the results of “charge amount” under low temperature and low humidity, and “initial charge amount”, “initial fog”, “charge amount after standing for 1 week” and “fog after standing” under high temperature and high humidity. The unit of charge amount is μc / g.

(Cleanability)
After the above-described fog evaluation under high temperature and high quality, 3000 images were drawn with an image having an image area ratio of 5%, and image defects due to poor cleaning were confirmed.

(Low temperature fixability, image gloss)
Developer (1) was filled in a developer of DocuPrint C2220 (Fuji Xerox Co., Ltd.) from which the fixing device was removed, and an unfixed image was collected. The image condition was a solid image of 40 mm × 50 mm, the toner amount was 1.5 mg / cm ² , and the recording paper was mirror-coated platinum paper (basis weight: 127 gsm). Subsequently, the fixing device of DocuPrint C2220 was modified so that the fixing temperature was variable, and the low temperature fixing property of the image was evaluated while the fixing temperature was increased stepwise from 100 ° C. to 200 ° C. Low-temperature fixability is achieved by bending a good fixed image with a certain load weight without image loss due to defective mold release, and then marking the degree of image loss at that portion, so that the fixing temperature at which a certain grade or higher is reached is minimized. The fixing temperature was used as an index of low-temperature fixability. The minimum fixing temperature is preferably 120 ° C. or lower. The results are shown in Table 2.

Further, the image glossiness of a sample fixed at a temperature 20 ° C. higher than the minimum fixing temperature was evaluated. The measurement was based on JIS Z 8741, using Gloss Meter GM-26D (Murakami Color Research Laboratory) at an incident angle of 75 °.
The numerical value of image gloss is preferably 50 or more, more preferably 60 or more. The results are shown in Table 2.

(Example 2)
Except for the crystalline polyester resin dispersion (1), the amorphous polyester resin dispersion (1) was replaced with 290.7 (293.7) parts in the production process of the toner (1) in Example 1. In the same manner as in Example 1, toner particles (2) and toner (2) were obtained.
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 1, the initial conductivity was 7 μS, and the initial Na ion amount was 10 ppm. The conductivity after 24 hours of dispersion was 9 μS, and the amount of Na ions after 14 hours of dispersion was 14 ppm.
The volume average particle size distribution index GSD _v of the toner particles (2) is 1.22, the number average particle size distribution index GSD _p is 1.24, the volume average particle size is 6.0 μm, and the shape factor SF1 is 130. .
Further, a developer (2) was produced in the same manner as in Example 1 except that in the production process of the developer (1) in Example 1, the toner (1) was changed to the toner (2). The toner (2) and developer (2) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 3)
Example 1 and Example 1 except that the crystalline polyester resin dispersion (1) was replaced with 90 parts and the non-crystalline polyester resin dispersion (1) was replaced with 177.3 parts in the production process of the toner (1) in Example 1. Similarly, toner particles (3) and toner (3) were obtained.
The conductivity and Na ion amount of the dispersion filtrate were measured in the same manner as in Example 1. As a result, the initial conductivity was 8 μS, and the initial Na ion amount was 12 ppm. The conductivity after 24 hours of dispersion was 10 μS, and the amount of Na ions after 15 hours of dispersion was 15 ppm.
The volume average particle size distribution index GSD _v of the toner particles (3) is 1.25, the number average particle size distribution index GSD _p is 1.26, the volume average particle size is 6.4 μm, and the shape factor SF1 is 134. .
Further, a developer (3) was produced in the same manner as in Example 1 except that in the production process of the developer (1) in Example 1, the toner (1) was changed to the toner (3). The toner (3) and developer (3) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

Example 4
In the production process of the toner (1) in Example 1, toner particles (4) were obtained in the same manner as in Example 1 except that the amorphous polyester resin dispersion (1) was changed to the amorphous polyester resin dispersion (2). ) And Toner (4) were obtained.
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 2, the initial conductivity was 9 μS, and the initial Na ion amount was 17 ppm. The conductivity after 24 hours of dispersion was 12 μS, and the amount of Na ions after 24 hours of dispersion was 23 ppm.
The volume average particle size distribution index GSD _v of the toner particles (3) is 1.23, the number average particle size distribution index GSD _p is 1.24, the volume average particle size is 5.8 μm, and the shape factor SF1 is 132. .
Further, a developer (4) was produced in the same manner as in Example 1 except that in the production process of the developer (1) in Example 1, the toner (1) was changed to the toner (4). Toner (4) and developer (4) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 5)
In the production process of the toner (1) in Example 1, [Step of washing with a treatment liquid having a pH of 9 or more and pH 10 or less] and [Step of washing with an ion exchange resin while being treated with ultrasonic waves after being adjusted to pH 4 or less] Toner particles (5) and toner (5) were obtained in the same manner as in Example 1 except that the number of repetitions was changed to 2 and the number of subsequent water washings was changed to 2 (washing (2) above).
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 1, the initial conductivity was 11 μS, and the initial Na ion amount was 18 ppm. The conductivity after 24 hours of dispersion was 16 μS, and the amount of Na ions after 24 hours of dispersion was 26 ppm.
The volume average particle size distribution index GSD _v of the toner particles (4) is 1.19, the number average particle size distribution index GSD _p is 1.23, the volume average particle size is 6.0 μm, and the shape factor SF1 is 130. .
Further, a developer (5) was produced in the same manner as in Example 1 except that in the production process of the developer (1) in Example 1, the toner (1) was changed to the toner (5). The toner (5) and developer (5) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Example 6)
In the fusing step in toner preparation, the toner particles (6) and toner (6) and toner (in the same manner as in Example 1 except that fusing was performed by raising the temperature to 95 ° C. and then lowering the pH to 7.0 and fusing for 3 hours. 6) was obtained. When the fused particles were observed with an optical microscope, it was confirmed that they were fused in a spherical shape.
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 1, the initial conductivity was 8 μS, and the initial Na ion amount was 9 ppm. Further, the conductivity after 24 hours of dispersion was 10 μS, and the amount of conductivity Na ions after 24 hours of dispersion was 13 ppm.
The volume average particle size distribution index GSD _v of the toner particles (6) is 1.23, the number average particle size distribution index GSD _p is 1.23, the volume average particle size is 6.0 μm, and the shape factor SF1 is 106. .
Further, a developer (6) was produced in the same manner as in Example 1 except that in the production process of the developer (1) in Example 1, the toner (1) was changed to the toner (6). The toner (6) and developer (6) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 1)
In the production process of the toner (2) in Example 2, the ultrasonic treatment and addition of the ion exchange resin were performed in the washing step [the step of washing with an ion exchange resin while being treated with ultrasonic waves after being adjusted to pH 4 or lower]. Toner particles (7) and toner (7) were obtained in the same manner as in Example 2 except for the above (washing (3) above).
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 2, the initial conductivity was 37 μS and the initial Na ion amount was 36 ppm. The conductivity after 24 hours of dispersion was 54 μS, and the conductivity Na ion amount after 24 hours of dispersion was 60 ppm.
The volume average particle size distribution index GSD _v of the toner particles (7) is 1.22, the number average particle size distribution index GSD _p is 1.24, the volume average particle size is 6.0 μm, and the shape factor SF1 is 130. .
Further, a developer (7) was produced in the same manner as in Example 1 except that the toner (1) was replaced with the toner (7) in the production process of the developer (1) in Example 1. Toner (7) and developer (7) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 2)
In the production process of the toner (7) in Comparative Example 1, the pH is not adjusted in the washing step [the step of washing with an ion exchange resin while reducing the pH to 4 or less and then treating with ultrasonic waves] [with ion exchange water] The toner particles (8) and the toner (8) were obtained in the same manner as in Comparative Example 1 except that the number of washing steps] was changed to 2 (washing (4) above).
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 2, the initial conductivity was 40 μS, and the initial Na ion amount was 62 ppm. The conductivity after 24 hours of dispersion was 62 μS, and the amount of Na ions after 24 hours of dispersion was 88 ppm.
The volume average particle size distribution index GSD _v of the toner particles (8) is 1.22, the number average particle size distribution index GSD _p is 1.24, the volume average particle size is 6.0 μm, and the shape factor SF1 is 130. .
Further, in the production process of the developer (1) in Example 1, the toner (1) is replaced with the toner (
A developer (8) was produced in the same manner as in Example 1, except that the procedure was changed to 8). The toner (8) and developer (8) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 3)
In the production process of the toner (2) in Example 2, toner particles (9) were obtained in the same manner as in Example 2 except that the amorphous polyester resin dispersion (1) was replaced with the amorphous polyester resin dispersion (3). ) And toner (9) were obtained.
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 2, the initial conductivity was 5 μS, and the initial Na ion amount was 10 ppm. The conductivity after 24 hours of dispersion was 6 μS, and the amount of Na ions after 14 hours of dispersion was 14 ppm.
Toner (9) had a resin acid value that was too low, so the emulsified particle size was large, and the speed of aggregation was high, resulting in a large particle size and a volume average particle size of 7.6 μm. Further, since the resin acid value was low, the chargeability was not sufficient and the charge amount was low. In addition, the shape progression rate was remarkably high, and the shape factor SF1 of the toner (9) obtained was 108 although it was already spherical at the time when the temperature was raised to 95 ° C. and the fusion was stopped immediately.
The volume average particle size distribution index GSD _v was 1.32 and the number average particle size distribution index GSD _p was 1.34. The toner particle size distribution was wide and the amount of toner remaining on the sieve was large.
A developer (9) was produced in the same manner as in Example 1, except that the toner (1) was replaced with the toner (9) in the production process of the developer (1) in Example 1. The toner (9) and developer (9) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

(Comparative Example 4)
In the production process of the toner (2) in Example 2, the non-crystalline polyester resin dispersion (1) was replaced with the non-crystalline polyester resin dispersion (4). Fusion was performed by reducing to 7.0. When they were fused for 5 hours and observed with an optical microscope, they were not fused well and the shape change did not progress. When the pH was further reduced to 6.0, the shape change gradually progressed, but since the particle size increased and the amount of coarse powder increased, it was not possible to finally obtain toner particles worthy of evaluation.

(Comparative Example 5)
-Amorphous polyester resin (1) 790 parts-Crystalline polyester resin (1) 80 parts-Paraffin wax (manufactured by Nippon Seiwa Co., Ltd., HNP-9, melting point: 75 ° C) 80 parts-Cyan pigment (Daisensei) Chemical Blue, Pigment Blue 15: 3 (copper phthalocyanine))
50 parts The raw materials were mixed with a Henschel mixer, melt-kneaded with a Banbury mixer, rolled, and roughly crushed with a hammer mill. Next, it was pulverized to 6.4 μm with a jet mill pulverizer and classified with an elbow jet classifier to obtain toner particles (10) and toner (10).
When the conductivity and Na ion amount of the filtrate of the dispersion liquid were measured in the same manner as in Example 1, the initial conductivity was 3 μS, and the initial Na ion amount was 2 ppm. The conductivity after 24 hours of dispersion was 5 μS, and the amount of Na ions after 3 hours of dispersion was 3 ppm.
The volume average particle size distribution index GSD _v after classification of the toner particles (10) is 1.30, the number average particle size distribution index GSD _p is 1.31, the volume average particle size is 6.2 μm, and the shape factor SF1 is 142. there were.
A developer (10) was produced in the same manner as in Example 1 except that the toner (1) was replaced with the toner (10) in the production process of the developer (1) in Example 1. The toner (10) and developer (10) were evaluated in the same manner as in Example 1. The results are shown in Table 2.

In Table 2, “EA” means an emulsion aggregation method.
As can be seen from Table 2, in the examples, the initial Na ion amount (a) and the difference between the initial Na ion amount (a) of the toner dispersion and the Na ion amount (b) after 24 hours of dispersion are small. It was found that it was in an excellent condition with almost no fogging. Further, it was found that even when the toner contains 25% by mass of the crystalline resin, the toner that has undergone the washing step in the embodiment has a large charge amount under both low temperature and low humidity conditions and high temperature and high humidity conditions.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment. It is a schematic structure figure showing an example of a process cartridge concerning an embodiment.

Explanation of symbols

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

Claims (2)

A step of obtaining a toner containing a polyester resin having at least an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less by a wet method, and when the obtained toner is dispersed in an aqueous medium, The initial Na ion amount (a) of the toner is 50 ppm or less, and the difference (b−a) between the initial Na ion amount (a) and the Na ion amount (b) in the toner dispersion after 24 hours of dispersion. There until 20ppm or less, have a cleaning step of cleaning the toner, the cleaning step, a step of washing the toner pH9 above pH10 by the following treatment solution, after the toner to pH4 or less, ultrasonic A method for producing a toner for developing an electrostatic charge image , comprising: a step of washing with an ion exchange resin while treating the toner, and a step of washing the toner with ion exchange water . When at least an acid value of 5 mgKOH / g or more and 25 mgKOH / g or less of a polyester resin, a colorant, and a release agent, and a toner produced by a wet method is dispersed in an aqueous medium,
The initial Na ion amount (a) in the toner dispersion is 50 ppm or less, and the difference between the initial Na ion amount (a) and the Na ion amount (b) in the toner dispersion after dispersion for 24 hours ( b-a) until a 20ppm or less, it has a cleaning step of cleaning the toner, the cleaning step, a step of washing the toner pH9 above pH10 by the following treatment solution was the toner to pH4 or less A method for cleaning an electrostatic charge image developing toner , comprising: a step of washing with an ion exchange resin while treating with ultrasonic waves; and a step of washing the toner with ion exchange water .

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