JP2019015924A - Image forming method and toner set for electrostatic latent image development - Google Patents

Abstract

To provide an image forming method or a toner set that can achieve both low glossiness and low-temperature fixability in outputting an image with a large amount of toner attached to it.SOLUTION: An image forming method for forming an image on a recording medium by superimposing toner images in a plurality of colors, where toner for electrostatic latent image development in a plurality of colors forming the toner images each contains amorphous and crystalline polyester resins; when an absorption spectrum is measured by a total reflection method by using a Fourier transform infrared spectroscopic analysis measuring device, the absorption wave number has the absorption maximum peak at least within a range of 690 to 710 cmand within a range of 1190 to 1220 cm; when the peak height when the absorption wave number has the absorption maximum peak within a range of 690 to 710 cmis P1, the peak height when the absorption wave number has the absorption maximum peak within a range of 1190 to 1220 cmis P2, and the ratio of the P2 to the P1 in each toner is W=P2/P1, the ratio of W(MAX) to the minimum value W(MIN), W(MAX)/W(MIN) is 1.20 to 20.00.SELECTED DRAWING: None

Description

  The present invention relates to an image forming method and an electrostatic latent image developing toner set.

  In recent years, from the viewpoint of speeding up and energy saving, development of a toner that can be fixed at a low temperature in order to fix a toner image with less energy has been promoted. In order to lower the toner fixing temperature, it is necessary to lower the melting temperature and melt viscosity of the resin. As one of means for achieving the above, there is known a method in which a crystalline resin such as a crystalline polyester resin excellent in sharp melt property is used as a binder resin. However, if the glass transition temperature or molecular weight of the resin is lowered in order to lower the melting temperature or melt viscosity of the resin, there arises a new problem that the toner aggregates under high temperature storage and the heat resistant storage property is lowered.

  In order to achieve both low-temperature fixability and heat-resistant storage stability, Patent Documents 1 to 4 propose to optimize the ratio of the crystalline polyester resin on the toner surface. Specifically, the ratio between the peak height of the spectrum derived from the crystalline polyester resin and the peak height of the spectrum derived from the amorphous resin is defined.

  Patent Documents 5 to 6 specify the ratio of the peak height of the spectrum derived from the styrene acrylic resin to the peak height of the spectrum derived from the crystalline polyester resin in the toner containing the crystalline polyester resin and the styrene acrylic resin. doing.

JP 2014-174315 A JP 2014-174186 A JP 2014-174262 A JP 2007-206097 A JP 2006-170195 A JP, 2006-197139, A

  As described above, it is possible to achieve both low-temperature fixability and heat-resistant storage stability by controlling the presence state of the crystalline polyester present in the vicinity of the toner surface, but the meltability during fixing is very high, The glossiness of the image becomes high, and it becomes difficult to output a low-gloss image, particularly for an image having a large amount of toner adhesion. Although it is possible to reduce the gloss by reducing the amount of crystalline polyester used or by increasing the elasticity of the binder resin, the low-temperature fixability deteriorates. Thus, it has been difficult for the conventional technology to achieve both low gloss and low temperature fixability when outputting a high adhesion amount image.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming method or toner set capable of achieving both low gloss and low temperature fixability when outputting a high adhesion amount image.

The present invention relates to an image forming method for forming an image on a recording medium by superimposing toner images for developing a plurality of colors of electrostatic latent images, the toner for developing a plurality of colors of electrostatic latent images forming the toner image Each of which includes an amorphous resin and a crystalline polyester resin, and has an absorption wave number of at least 690 to 710 cm ⁻¹ when an absorption spectrum is measured by a total reflection method using a Fourier transform infrared spectroscopic analyzer. range and has a maximum absorption peak in the range of 1190~1220cm ^-1, the peak height of the absorption maximum peak in a range wherein the absorption wave numbers of 690~710cm ^-1 P1, the absorption wave numbers 1190～1220Cm ^-1 When the peak height of the absorption maximum peak within the range of P2 is P2, and the ratio of P2 to P1 in each toner is W = P2 / P1, the minimum value W ( The ratio of W (MAX) to MIN) is an image forming method in which W (MAX) / W (MIN) is 1.20 to 20.00.

  According to the present invention, it is possible to achieve both low gloss and low temperature fixability when outputting a high adhesion amount image.

It is the figure which showed an example of the absorption spectrum obtained by the total reflection method (ATR method) in the range including an absorption wave number of 690-710 cm < ^-1 >. It is the figure which showed an example of the absorption spectrum obtained by the total reflection method (ATR method) in the range containing 1190-1220 cm < ^-1 > of absorption wave numbers.

A first embodiment of the present invention is an image forming method for forming an image on a recording medium by superimposing toner images for developing a plurality of colors of electrostatic latent images. Each of the image developing toners contains an amorphous resin and a crystalline polyester resin, and when the absorption spectrum is measured by a total reflection method using a Fourier transform infrared spectroscopic analyzer, the absorption wave number is at least 690 to in the range of 710 cm ^-1 and has an absorption maximum peak in the range of 1190~1220cm ^-1, the peak height of the absorption maximum peak in the range absorption wave numbers of 690~710cm ^-1 P1, absorption wave numbers 1190～1220Cm ^The minimum value W (MIN) when the peak height of the absorption maximum peak in the range of ⁻¹ is P2, and the ratio of P2 to P1 in each toner is W = P2 / P1. The ratio of W (MAX) to W (MAX) / W (MIN) is 1.20 to 20.00.

A second embodiment of the present invention is a toner set including a toner for developing electrostatic latent images of a plurality of colors, each of the toners including an amorphous resin and a crystalline polyester resin, and Fourier transform infrared when the absorption spectrum was measured by a total reflection method using a spectrophotometer measuring device, having at least absorption wave absorption maximum peak within the range and 1190～1220Cm ^-1 of 690～710Cm ^-1, absorption wave numbers 690 The peak height of the absorption maximum peak in the range of ˜710 cm ⁻¹ is P1, the peak height of the absorption maximum peak in the range of 1190 to 1220 cm ⁻¹ is P2, and the ratio of P2 to P1 in each toner is P2. When W = P2 / P1, the ratio of W (MAX) to the minimum value W (MIN) W (MAX) / W (MIN) is 1.20 to 20.00 There is a toner set.

  Here, the toner set refers to a combination of toners that form different image forming layers when transferred onto a recording medium. Therefore, for example, a combination of white toner and black toner that forms a gray image by packing black toner and white toner in one toner bottle is not included in the toner set here.

  Hereinafter, the ratio of W (MAX) to the minimum value W (MIN) W (MAX) / W (MIN) is simply referred to as W (MAX) / W (MIN).

  According to the image forming method according to the first embodiment, it is possible to achieve both low gloss and low temperature fixability when outputting a high adhesion amount image. Further, the same effect as described above can be obtained by using the toner set according to the second embodiment. Although the mechanism of action by which the above-described effect can be obtained by such a configuration of the present invention is unknown, it is considered as follows.

  When each toner has W (MAX) / W (MIN) of 1.20 or more, the amount of crystalline polyester resin (hereinafter also simply referred to as CPES) on the toner surface is different. Toners having different melting properties are mixed. Thereby, smoothing of the image surface after fixing is suppressed while maintaining the meltability of the toner layer at the time of fixing. Therefore, it is considered that high gloss is suppressed when W (MAX) / W (MIN) is 1.20 or more. On the other hand, if W (MAX) / W (MIN) exceeds 20.00, the difference in meltability at the time of fixing between toners becomes too large, so that the low-temperature fixability is considered to deteriorate. Further, when W (MAX) / W (MIN) is less than 1.20, the meltability at the time of fixing is almost the same between the toners, and the surface of the image after fixing is easily smoothed. It is thought to increase.

  In addition, the said mechanism is based on estimation and this invention is not restrict | limited to the said mechanism at all.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not limited only to the following embodiment. In this specification, “X to Y” indicating a range includes X and Y, and means “X or more and Y or less”. Unless otherwise specified, operations and physical properties are measured under conditions of room temperature (25 ° C.) / Relative humidity 40 to 50% RH. Furthermore, in this specification, (meth) acryl is a general term for acrylic and methacrylic.

  As described above, the image forming method and the toner set according to the present invention are characterized by combinations of toners. Therefore, in the following, first, the configuration of each toner will be described in detail.

<Toner (electrostatic latent image developing toner)>
The “toner” according to the present invention refers to an aggregate of “toner particles”. The toner particles include an amorphous resin and a crystalline polyester resin as a binder resin, and if necessary, are composed of toner base particles including a colorant, a release agent, and an internal additive, and an external additive. The The toner base particles may be used as toner particles as they are.

  In the present invention, toners of a plurality of colors are used. As the toner used here, a toner that forms a secondary color of yellow toner (Y), magenta toner (M), cyan toner (C), and black toner (K) (hereinafter also simply referred to as YMCK), oxidation toner A white toner (W) containing a white colorant (pigment) such as titanium, a metallic toner (ME) containing a metallic colorant (pigment) such as aluminum powder, or a colorant (pigment). Transparent toner not included (clear toner: (CL)) and the like may be mentioned, and any combination thereof may be used. The secondary color is a cyan toner containing a cyan colorant (pigment) which is a basic color of the color material used, a magenta toner containing a magenta colorant (pigment), or a yellow colorant. It is a color formed by superposing at least two color toner images selected from yellow toner containing (pigment) or black toner containing black colorant (pigment). The toner that forms the secondary color is also referred to as a color toner, and the above-described yellow toner (Y), magenta toner (M), cyan toner (C), and black toner (K) (hereinafter also simply referred to as YMCK). Basic. Such color toners based on YMCK can form images of various colors by superimposing the toners. On the other hand, white toner or the like is also referred to as a special color toner, and is a toner used for image formation as a single color other than YMCK, which is a toner (color toner) that forms a secondary color, and is also referred to as a spot color. These special color toners are used to improve the added value of an image, and white, metallic, and transparent toners are particularly high added value toner groups that can express a single color that cannot be expressed by a color toner, By being present in the upper layer or the lower layer of the color toner, color development and gloss of the color toner can be enhanced.

  In the image forming method of the first embodiment or the toner set of the second embodiment, the electrostatic latent image developing toners of a plurality of colors are yellow toner (Y), magenta toner (M), cyan toner (C), and It is preferable that there are at least two selected from the group consisting of black toner (K).

  Here, the plurality of colors is an integer equal to or greater than 2, and is the number of toners used in image formation or the number of toners constituting a toner set. For example, when four colors of yellow toner (Y), magenta toner (M), cyan toner (C), and black toner (K) are used for image formation, the plurality of colors are the above four colors.

Each of the toners for developing electrostatic latent images of a plurality of colors has at least an absorption wave number in the range of 690 to 710 cm ⁻¹ and 1190 when an absorption spectrum is measured by a total reflection method using a Fourier transform infrared spectroscopic analyzer. It has an absorption maximum peak in the range of ˜1220 cm ⁻¹ .

  The absorption spectrum by the total reflection method is measured as follows.

First, 0.2 g of toner as a sample is pressurized with a pellet molding machine (SSP-10A: manufactured by Shimadzu Corporation) for 1 minute at a load of 400 kgf to produce a pellet having a diameter of 10 mm. An absorption spectrum is obtained by a total reflection method (ATR method) using Nicolet 380 manufactured by ThermoFisher Scientific, which is a Fourier transform infrared spectrometer. The ATR measurement is performed using a diamond crystal under the conditions of a resolution of 4 cm ⁻¹ and an integration count of 32 times. Further, the following numerical values are defined from the peak intensity ratio of the spectrum obtained by performing ATR correction on the obtained ATR spectrum based on the correction method of the model.

The absorption maximum peak having an absorption wave number in the range of 690 to 710 cm ⁻¹ is a C—H peak of monosubstituted benzene derived from a styrene resin. And the peak height P1 of the absorption maximum peak in the range whose absorption wave number is 690-710 cm < ^-1 > is defined as follows. Between 690 to 710 cm ^−1, the falling peak point where the absorbance is the smallest (hereinafter referred to as “first falling peak point Fp1”. Usually, the point at 690 cm ⁻¹ ), and the absorbance is the second. There is a maximum rising peak point Mp at which the absorbance is maximum between a decreasing falling peak point (hereinafter referred to as “second falling peak point Fp2”, usually a point of 710 cm ⁻¹ ). A line segment connecting the first falling peak point Fp1 and the second falling peak point Fp2 is defined as a base line. Then, a vertical line is drawn from the maximum rising peak point Mp toward the horizontal axis, and the absolute value of the difference between the absorbance at the intersection with the baseline and the absorbance at the maximum rising peak point Mp is expressed as the height P1 of the maximum rising peak point Mp. And FIG. 1 shows an example of an absorption spectrum obtained by the ATR method in a range where the absorption wave number includes 690 to 710 cm ⁻¹ .

The absorption maximum peak having an absorption wave number in the range of 1190 to 1220 cm ⁻¹ is a C—O—C peak derived from the crystalline polyester resin. And the peak height P2 of the absorption maximum peak in the range whose absorption wave number is 1190-1220 cm < ^-1 > is defined as follows. A falling peak point with the lowest absorbance (hereinafter referred to as “first falling peak point”) and a falling peak point with the second lowest absorbance (hereinafter referred to as “second falling peak point”). Between the first falling peak point and the second falling peak point is a baseline. Then, a perpendicular line is drawn from the maximum rising peak point toward the horizontal axis, and the absolute value of the difference between the absorbance at the intersection with the baseline and the absorbance at the maximum rising peak point is defined as the height P2 of the maximum rising peak point. FIG. 2 shows an example of an absorption spectrum obtained by the ATR method in a range where the absorption wave number includes 1190 to 1220 cm ⁻¹ .

In this specification, the peak height of the absorption maximum peak in the range absorption wave numbers of 690~710cm ^-1 P1, the peak height of the absorption maximum peak in the range of absorption wave numbers 1190～1220Cm ^-1 and P2 The ratio of P2 to P1 in each toner is W = P2 / P1. Hereinafter, the ratio W = P2 / P1 of P2 to P1 in each toner is also simply referred to as a peak height ratio W.

  Generally, a toner is composed of a binder resin, a colorant, a release agent, and the like. In view of the components constituting these, W corresponds to the content ratio of CPES and styrene resin on the toner particle surface. . That is, it can be said that the peak height ratio W detects the CPES amount with respect to the styrene resin amount existing in the vicinity of the toner surface.

  The peak height ratio W of each toner is preferably 0.01 or more, more preferably 0.02 or more, and further preferably 0.04 or more. When W is in the above range, the low-temperature fixability is improved. Further, the peak height ratio W of each toner is preferably 1.00 or less, more preferably 0.80 or less, further preferably 0.40 or less, from the viewpoint of heat-resistant storage stability. It is especially preferable that it is 0.30 or less. Note that W is a value obtained up to the second decimal place. The peak height ratio W of each toner is preferably 0.01 to 1.00, more preferably 0.02 to 1.00, and more preferably 0.04 to 1.00. It is more preferable that it is 0.04-0.40. When the peak height ratio W is large, a lot of CPES is present on the toner surface and melts quickly at the time of fixing. When the peak height ratio W is small, the low-temperature fixability is lowered. By setting the peak height ratio in the range of 0.01 to 1.00, the ratio of the styrene resin that is hardly compatible with CPES is optimized, and both heat-resistant storage properties and low-temperature fixability can be achieved.

  The method for controlling the peak height ratio W is not particularly limited, but in order to increase the peak height ratio W, the CPES may be controlled to be exposed on the toner particle surface. In order to reduce the ratio W, CPES may be controlled so as not to be exposed on the toner particle surface.

  As a method for controlling the peak height ratio W, specifically, for example, in the emulsion aggregation method, in the aggregation / fusion process at the time of core particle preparation of the core-shell particles, the crystalline polyester resin is added to the styrene resin particle dispersion. Controlling the temperature when the particle dispersion is charged and / or the particle diameter of the styrene resin particles when the crystalline polyester resin particle dispersion is charged into the styrene resin particle dispersion may be mentioned.

  In order to control the CPES to be exposed on the toner particle surface, for example, the temperature at which the crystalline polyester resin particle dispersion is introduced into the styrene resin particle dispersion (first stage dispersion introduction temperature) is increased (input). By increasing the temperature, the fusion of the styrene resin particles progresses, making it difficult for CPES to be taken into the interior.), The styrene system when the crystalline polyester resin particle dispersion is introduced into the styrene resin particle dispersion A method such as increasing the particle diameter of the resin particles (first stage dispersion charging temperature) (the CPES particles are less likely to be taken into the styrene resin particles due to the large particle diameter of the styrene resin particles) can be considered.

  On the other hand, in order to control the CPES not to be exposed on the toner particle surface, for example, the temperature at which the crystalline polyester resin particle dispersion is introduced into the styrene resin particle dispersion (first stage dispersion introduction temperature) is lowered. (By lowering the charging temperature, it becomes difficult for the styrenic resin particles to fuse with each other and CPES is easily taken into the inside.) The crystalline polyester resin particle dispersion is charged into the styrene resin particle dispersion. The particle diameter of the styrene-based resin particles (first stage dispersion charging temperature) is reduced (the CPES particles are easily taken into the styrene-based resin particles because the particle diameter of the styrene-based resin particles is small). A method is conceivable.

  Moreover, the crystalline polyester resin having a hybrid structure tends to have a higher peak height ratio W than the crystalline polyester resin having no hybrid structure.

  Considering the peak height ratio W, the first-stage dispersion charging temperature is not particularly limited, but is preferably 70 to 90 ° C, and more preferably 75 to 85 ° C. Further, the particle diameter of the first-stage dispersion is preferably from about 5.0 μm or less before the start of particle size growth, and more preferably from about 4.5 μm or less before the start of particle size growth.

  In each toner W, when the minimum value W is W (MIN) and the maximum value W is W (MAX), the ratio of W (MAX) to W (MIN) is W (MAX) / W (MIN). 1.20 to 20.00. When W (MAX) / W (MIN) is 1.20 or more, glossiness at the time of outputting a high adhesion amount image is remarkably suppressed (for example, see Example 1 and Comparative Example 1 described later). Further, by setting W (MAX) / W (MIN) to 20.00 or less, the low-temperature fixability is remarkably improved (for example, see Example 10 and Comparative Example 2 described later). W (MAX) / W (MIN) is preferably 1.50 to 20.00 from the viewpoint of suppressing gloss, and 1.50 to 15.00 from the viewpoint of low-temperature fixability. Is more preferable, and from the viewpoint of achieving both low-temperature fixability and suppression of gloss, it is more preferably 2.00 to 10.00, still more preferably 2.50 to 10.00, and 2.75. It is especially preferable that it is -7.50. For the peak height ratio, a value obtained up to the second decimal place is adopted.

  W (MAX) / W (MIN) can be controlled by appropriately setting W of each toner. Preferably, toner particles having W of 0.01 to 1.00 are used, and W (MAX) / W ( (MIN) may be selected to be within the above range.

  Regarding the inter-color difference of YMCK, the peak height ratio may be different for only one color, the peak height ratio may be different for a plurality of colors, or the peak height ratio may be different for all colors.

[Toner particles]
The toner particles according to the present invention contain an amorphous resin and a crystalline polyester resin as a binder resin. The toner particles may contain other toner constituents such as a release agent, a colorant corresponding to each color, and a charge control agent, if necessary. Hereinafter, each component constituting the toner particles will be described.

  A preferred embodiment of the present invention is a hybrid crystalline polyester resin in which a crystalline polyester resin is a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene chemically bonded. Is a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded.

  In one embodiment of the present invention, the toner base particles have a core-shell structure having a core portion including a styrene resin and a crystalline polyester resin, and a shell portion including a styrene resin. By adopting such a structure, the heat-resistant storage property and the low-temperature fixability are ensured, and the control is facilitated so that the peak height ratio W falls within the preferable range.

  Moreover, it is preferable that the styrene resin which forms a core part is a multilayer resin particle containing multiple layers. This is because by using a plurality of layers, the wax can be contained in an inner layer that is not the outermost layer, and by suppressing the exposure of the wax to the surface, it is possible to suppress a decrease in heat resistant storage stability. Here, the number of layers in the case of a multilayer structure is not particularly limited, but in consideration of productivity and effects, it is preferably 2 to 5 layers, more preferably 2 to 3 layers. .

  The shell portion may not cover the entire surface of the core portion, and the core portion may be partially exposed. The cross section of the core-shell structure can be confirmed by known observation means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM).

  In the case of the core-shell structure, characteristics such as glass transition temperature, melting point, and hardness can be made different between the core portion and the shell portion, and toner particles can be designed according to the purpose. For example, a resin having a relatively high glass transition temperature (Tg) is agglomerated and fused on the surface of a core portion containing a binder resin, a colorant, a release agent, etc. and having a relatively low glass transition temperature (Tg). Thus, the shell portion can be formed.

  The inclusion of the crystalline polyester resin and the wax in the core is, for example, by known observation means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM). Can be confirmed.

≪Crystalline polyester resin≫
The toner particles contain a crystalline polyester resin as a binder resin. Therefore, at the time of heat fixing, the crystalline polyester resin and the amorphous resin are compatible with each other, and the low temperature fixability of the toner can be improved.

  “Crystalline polyester resin” means a known polyester obtained by a polycondensation reaction of a divalent or higher carboxylic acid (polyvalent carboxylic acid) and its derivative with a divalent or higher alcohol (polyhydric alcohol) and its derivative. Among the resins, in differential scanning calorimetry (DSC), it refers to a resin having a clear endothermic peak, not a stepwise endothermic change. Specifically, the clear endothermic peak means that the half-value width of the endothermic peak is within 15 ° C. when measured at a heating rate of 10 ° C./min in the differential scanning calorimetry (DSC) described in the following examples. It means a certain peak.

  Differential scanning calorimetry (DSC) can be measured using, for example, a differential scanning calorimeter “Diamond DSC” (manufactured by PerkinElmer). The measurement is a first temperature rising process in which the temperature is raised from room temperature (25 ° C.) to 150 ° C. at an ascending / descending rate of 10 ° C./min and held isothermally at 150 ° C. for 5 minutes. Measurement conditions (temperature increase / cooling conditions) that pass through a cooling process in which the temperature is cooled to 0 ° C. for 5 minutes and a second temperature increase process in which the temperature is increased from 0 ° C. to 150 ° C. at a rate of 10 ° C./min. ). The above measurement is performed by enclosing 3.0 mg of a sample in an aluminum pan and setting it in a sample holder of a differential scanning calorimeter “Diamond DSC”. Use an empty aluminum pan as a reference.

  In the above measurement, analysis is performed from the endothermic curve obtained by the first temperature raising process, and the top temperature of the endothermic peak derived from the crystalline polyester resin is defined as the melting point of the crystalline polyester resin.

  Examples of the polyvalent carboxylic acid derivatives include alkyl esters, acid anhydrides, and acid chlorides of polyvalent carboxylic acids. Examples of the polyhydric alcohol derivatives include ester compounds of polyhydric alcohols and hydroxycarboxylic acids.

  The polyvalent carboxylic acid is a compound containing two or more carboxyl groups in one molecule. Of these, divalent carboxylic acids are compounds containing two carboxyl groups in one molecule, such as oxalic acid, malonic acid, succinic acid, adipic acid, pimelic acid, sebacic acid, azelaic acid, n-dodecyl. Succinic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid (dodecanedioic acid), 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid (tetradecanedioic acid), 1,13-tri Saturated aliphatic dicarboxylic acids such as decanedicarboxylic acid and 1,14-tetradecanedicarboxylic acid; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, itaconic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid can be mentioned. Examples of polyvalent carboxylic acids other than divalent carboxylic acids include trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid. Examples of the derivative of the polyvalent carboxylic acid include anhydrides of these carboxylic acid compounds or alkyl esters having 1 to 3 carbon atoms. These may be used individually by 1 type and may be used in combination of 2 or more type.

  A polyhydric alcohol is a compound containing two or more hydroxyl groups in one molecule. Among these, divalent polyols (diols) are compounds containing two hydroxy groups in one molecule, such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12- Mention may be made of aliphatic diols such as dodecanediol, neopentyl glycol, 1,4-butenediol. Examples of polyols other than divalent polyols include trihydric or higher polyhydric alcohols such as glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Further, it may be partially branched or cross-linked by selecting the valence of the polyvalent carboxylic acid or the valence of the polyhydric alcohol.

  The formation method of the crystalline polyester resin using the monomer is not particularly limited, and by polycondensing (esterifying) the polyvalent carboxylic acid and the polyhydric alcohol using a known esterification catalyst. The resin can be formed. Examples of esterification catalysts that can be used include titanium monocarboxylates such as titanium acetate, titanium propionate, titanium hexanoate, and titanium octoate, titanium oxalate, titanium succinate, titanium maleate, titanium adipate, and sebacic acid. Aliphatic carboxylic acids such as titanium, aliphatic dicarboxylic acid titanium such as titanium, hexane tricarboxylic acid titanium, isooctane tricarboxylic acid etc. titanium tricarboxylic acid titanium, octane tetracarboxylic acid titanium, decane tetracarboxylic acid titanium etc. Titanium monocarboxylic acid, titanium monobenzoate, titanium phthalate, titanium terephthalate, titanium isophthalate, titanium naphthalenedicarboxylate, titanium biphenyl dicarboxylate, titanium anthracene dicarboxylate, etc. Aromatic dicarboxylic acid titanium; aromatic tricarboxylic acid titanium such as trimellitic acid titanium and naphthalene tricarboxylic acid titanium; aromatic tetracarboxylic acid titanium such as benzenetetracarboxylic acid titanium and naphthalene tetracarboxylic acid titanium; , Titanyl compounds of aliphatic and titanium aromatic carboxylates and alkali metal salts thereof, titanium halides such as dichlorotitanium, trichlorotitanium, tetrachlorotitanium, tetrabromotitanium, tetrabutoxytitanium (titanium) Tetrabutoxide), tetraalkoxytitanium such as tetraoctoxytitanium, tetrastearyloxytitanium, titanium acetylacetonate, titanium diisopropoxide bisacetylacetonate, titanium triethano Ruamineto, and titanium-containing catalysts, such as.

  The melting point (Tm) of the crystalline polyester resin is preferably in the range of 50 to 90 ° C., and preferably in the range of 60 to 80 ° C., from the viewpoint of obtaining sufficient low-temperature fixability and heat-resistant storage stability. preferable. As the melting point (Tm) of the crystalline polyester resin, a value measured by the method described in Examples is adopted.

  The weight average molecular weight (Mw) of the crystalline polyester resin is preferably 5,000 to 50,000, more preferably 5,000 to 30,000, from the viewpoints of low-temperature fixability and gloss stability. preferable.

  The content of the crystalline polyester resin is preferably 1 to 30% by mass and more preferably 3 to 25% by mass with respect to the total mass of the crystalline polyester resin and the amorphous resin, respectively. Preferably, it is 5-20 mass% especially preferable. Within such a range, the low-temperature fixability is excellent and the density of the formed image is also improved.

  The crystalline polyester resin is a hybrid in which a crystalline polyester polymer segment and an amorphous polymer segment other than the polyester resin (sometimes referred to simply as “amorphous polymer segment” in this specification) are chemically bonded. A crystalline polyester resin may be used.

  Due to the presence of the amorphous polymer segment, the affinity between the hybrid resin and the amorphous resin is improved, the hybrid resin is easily incorporated into the amorphous resin, and the charging uniformity and the like can be improved. .

  The crystalline polyester polymer segment is not described because it is composed of the crystalline polyester resin.

  The amorphous polymer segment is a portion derived from an amorphous resin other than the crystalline polyester resin. The presence of an amorphous polymer segment in the hybrid resin (and also in the toner) can be confirmed by specifying the chemical structure using, for example, NMR measurement or methylation reaction Py-GC / MS measurement. .

  The amorphous polymer segment does not have a melting point and has a relatively high glass transition temperature (Tg) when differential scanning calorimetry (DSC) is performed on a resin having the same chemical structure and molecular weight as the unit. It is a polymerization segment. At this time, for a resin having the same chemical structure and molecular weight as the unit, the glass transition temperature (Tg1) in the first temperature rising process in DSC measurement is preferably 30 to 80 ° C., particularly 40 to 65 ° C. Preferably there is. In addition, glass transition temperature (Tg1) can be measured by the method as described in an Example.

  The amorphous polymer segment is not particularly limited as long as it is defined above. For example, this resin is used for a resin having a structure in which other components are copolymerized with a main chain of an amorphous polymer segment and a resin having a structure in which an amorphous polymer segment is copolymerized with a main chain composed of other components. If the toner to be contained has an amorphous polymer segment as described above, the resin corresponds to the hybrid resin having an amorphous polymer segment in the present invention.

  The resin component constituting the amorphous polymer segment is not particularly limited, and examples thereof include a vinyl polymer segment, a urethane polymer segment, and a urea polymer segment. Among these, a vinyl polymer segment is preferable because it is easy to control thermoplasticity.

  The vinyl polymerized segment is not particularly limited as long as it is a polymerized vinyl compound, but preferably has a structural unit derived from styrene in view of plasticity during heat fixing. That is, the crystalline polyester resin is preferably a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. For the same reason, the vinyl polymer segment is more preferably a styrene acrylic polymer segment.

  Therefore, hereinafter, the styrene acrylic polymer segment as the amorphous polymer segment will be described.

The styrene acrylic polymerization segment is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. Styrene monomer as referred to herein, in addition to styrene represented by the structural formula _{CH 2 = CH-C 6 H} 5, is intended to include a structure having a known side-chain or functional groups styrene structure. In addition, the (meth) acrylic acid ester monomer referred to here is an acrylic acid ester derivative or methacrylic acid in addition to the acrylic acid ester compound or methacrylic acid ester compound represented by CH ₂ = CHCOOR (R is an alkyl group). It includes an ester compound having a known side chain or functional group in the structure of an ester derivative or the like.

  Specific examples of the styrene monomer and the (meth) acrylic acid ester monomer are shown below, but those usable for forming the styrene acrylic polymer segment used in the present invention are limited to those shown below. It is not a thing.

  First, specific examples of the styrene monomer include, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p-ethylstyrene, 2,4- Examples thereof include dimethyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, and pn-dodecyl styrene. These styrene monomers can be used alone or in combination of two or more.

  Specific examples of the (meth) acrylic acid ester monomer include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, t-butyl acrylate, isobutyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate. Acrylate monomers such as stearyl acrylate, lauryl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isopropyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, Stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, diethylaminoethyl Methacrylate, methacrylic acid ester monomers such as dimethylaminoethyl methacrylate.

  In this specification, “(meth) acrylic acid ester monomer” is a general term for “acrylic acid ester monomer” and “methacrylic acid ester monomer”. “Methyl acrylate” is a general term for “methyl acrylate” and “methyl methacrylate”.

  These acrylic acid ester monomers or methacrylic acid ester monomers can be used alone or in combination of two or more. That is, a copolymer is formed using a styrene monomer and two or more acrylate monomers, and a copolymer is formed using a styrene monomer and two or more methacrylic ester monomers. Either a coalescence can be formed, or a copolymer can be formed by using a styrene monomer together with an acrylate monomer and a methacrylic acid ester monomer.

  The content of the structural unit derived from styrene (monomer) in the amorphous polymerization segment is preferably 40 to 90% by mass with respect to the total amount of the amorphous polymerization segment. Moreover, it is preferable that the content rate of the structural unit derived from the (meth) acrylic acid ester monomer in an amorphous polymerization segment is 10-60 mass% with respect to the whole quantity of an amorphous polymerization segment. By setting it as such a range, it becomes easy to control the plasticity of the hybrid resin.

  Furthermore, it is preferable that the amorphous polymerized segment is formed by addition polymerization of a compound for chemically bonding to the crystalline polyester polymerized segment in addition to the styrene monomer and the (meth) acrylate monomer. . Specifically, it is preferable to use a compound that is ester-bonded to a hydroxyl group derived from a polyhydric alcohol [—OH] or a carboxyl group derived from a polyvalent carboxylic acid [—COOH] contained in the crystalline polyester polymerization segment. Therefore, the amorphous polymerization segment can be addition-polymerized with respect to the styrene monomer and the (meth) acrylate monomer, and has a carboxyl group [—COOH] or a hydroxyl group [—OH]. It is preferable to further polymerize the compound.

  Examples of such compounds include compounds having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And compounds having a hydroxyl group such as polyethylene glycol mono (meth) acrylate.

  The content rate of the structural unit derived from the said compound in an amorphous polymerization segment is preferable in it being 0.5-20 mass% with respect to the whole quantity of an amorphous polymerization segment.

  The method for forming the styrene acrylic polymer segment is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the oil-soluble polymerization initiator include the following azo or diazo polymerization initiators and peroxide polymerization initiators.

  As the azo or diazo polymerization initiator, 2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1) -Carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, azobisisobutyronitrile and the like.

  As the peroxide polymerization initiator, benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, 2,4 -Dichlorobenzoyl peroxide, lauroyl peroxide, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine and the like.

  Moreover, when forming resin particles by an emulsion polymerization method, a water-soluble radical polymerization initiator can be used. Examples of the water-soluble radical polymerization initiator include persulfates such as potassium persulfate and ammonium persulfate, azobisaminodipropane acetate, azobiscyanovaleric acid and salts thereof, and hydrogen peroxide.

  The content of the amorphous polymer segment is preferably 3% by mass or more and less than 15% by mass with respect to the total amount of the hybrid crystalline polyester resin. By setting it as the above range, sufficient crystallinity can be imparted to the hybrid resin.

≪Method for producing hybrid crystalline polyester resin (hybrid resin) ≫
The method for producing the hybrid crystalline polyester resin is not particularly limited as long as it is a method capable of forming a polymer having a structure in which the crystalline polyester polymer segment and the amorphous polymer segment are chemically bonded. Absent. Specific examples of the method for producing the hybrid resin include the following methods.

(1) A method for producing a hybrid resin by polymerizing an amorphous polymer segment in advance and performing a polymerization reaction to form a crystalline polyester polymer segment in the presence of the amorphous polymer segment. An amorphous polymer segment is formed by an addition reaction of the monomer constituting the above amorphous polymer segment (preferably, a styrene monomer and a vinyl monomer such as a (meth) acrylate monomer). . Next, in the presence of the amorphous polymerization segment, a polyvalent carboxylic acid and a polyhydric alcohol are subjected to a polymerization reaction to form a crystalline polyester polymerization segment. At this time, a polyhydric carboxylic acid and a polyhydric alcohol are subjected to a condensation reaction, and a polycarboxylic acid or a polyhydric alcohol is added to the amorphous polymerization segment to form a hybrid resin.

  In the above method, it is preferable to incorporate a site where these units can react with each other in the crystalline polyester polymer segment or the amorphous polymer segment. Specifically, at the time of formation of the amorphous polymer segment, in addition to the monomer constituting the amorphous polymer segment, the carboxy group [—COOH] or hydroxyl group [—OH] remaining in the crystalline polyester polymer segment Also used are compounds having a site capable of reacting with and a site capable of reacting with the amorphous polymerized segment. That is, when this compound reacts with a carboxy group [—COOH] or a hydroxyl group [—OH] in the crystalline polyester polymerized segment, the crystalline polyester polymerized segment can be chemically bonded to the amorphous polymerized segment. it can.

  Alternatively, a compound having a site capable of reacting with a polyhydric alcohol or polyvalent carboxylic acid and capable of reacting with an amorphous polymer segment may be used when forming the crystalline polyester polymer segment.

  By using the above method, a hybrid resin having a structure (graft structure) in which a crystalline polyester polymer segment is chemically bonded to an amorphous polymer segment can be formed.

(2) A method of producing a hybrid resin by forming a crystalline polyester polymer segment and an amorphous polymer segment, respectively, and combining them. In this method, first, a polyvalent carboxylic acid and a polyhydric alcohol are condensed. React to form a crystalline polyester polymer segment. In addition to the reaction system for forming the crystalline polyester polymer segment, the monomer that constitutes the above-mentioned amorphous polymer segment is polymerized to form the amorphous polymer segment. At this time, it is preferable to incorporate a site where the crystalline polyester polymer segment and the amorphous polymer segment can react with each other. In addition, since the method of incorporating such a reactive site is as described above, detailed description thereof is omitted.

  Next, a hybrid resin having a structure in which the crystalline polyester polymer segment and the amorphous polymer segment are chemically bonded can be formed by reacting the crystalline polyester unit formed above with the amorphous polymer segment. it can.

  In addition, when the reactive site is not incorporated in the crystalline polyester polymerization segment and the amorphous polymerization segment, a system in which the crystalline polyester polymerization segment and the amorphous polymerization segment coexist is formed, You may employ | adopt the method of throwing in the compound which has a site | part which can be combined with a crystalline polyester polymerization segment and an amorphous polymerization segment. A hybrid resin having a structure in which the crystalline polyester polymer segment and the amorphous polymer segment are chemically bonded can be formed via the compound.

(3) A method for producing a hybrid resin by forming a crystalline polyester polymer segment in advance and performing a polymerization reaction to form an amorphous polymer segment in the presence of the crystalline polyester polymer segment. Polymerization is carried out by subjecting a polyvalent carboxylic acid and a polyhydric alcohol to a condensation reaction to form a crystalline polyester polymer segment. Next, in the presence of the crystalline polyester polymer segment, the monomer constituting the amorphous polymer segment is polymerized to form an amorphous polymer segment. At this time, it is preferable to incorporate a site where these units can react with each other in the crystalline polyester polymerized segment or the amorphous polymerized segment, as in the above (1). In addition, since the method of incorporating such a reactive site is as described above, detailed description thereof is omitted.

  By using the above method, a hybrid resin having a structure (graft structure) in which an amorphous polymer segment is chemically bonded to a crystalline polyester polymer segment can be formed.

  Among the methods (1) to (3), the method (1) facilitates the formation of a hybrid resin having a structure in which a crystalline polyester resin chain is grafted to an amorphous resin chain, and simplifies the production process. This is preferable because it is possible. In the method (1), since the amorphous polyester polymer segments are bonded after the amorphous polymer segments are formed in advance, the orientation of the crystalline polyester polymer segments tends to be uniform.

≪Amorphous resin≫
The amorphous resin is used as a binder resin together with the crystalline polyester resin to constitute toner base particles. By including an amorphous resin as the binder resin, it is possible to obtain an advantage that appropriate fixing strength and image gloss can be obtained, and good chargeability can be obtained even in a temperature and humidity fluctuation environment.

  The amorphous resin is preferably 50% by mass or more and more preferably 70 to 99% by mass with respect to the entire binder resin. The content of the amorphous resin is preferably 65 to 95% by mass, and 70 to 90% by mass with respect to the total mass of the crystalline polyester resin, the amorphous resin, and the release agent. Is more preferable. Within such a range, the low-temperature fixability is excellent and the density of the formed image is also improved.

  Here, the amorphous resin is a resin having a relatively high glass transition temperature (Tg) without having a melting point when differential scanning calorimetry (DSC) is performed. At this time, the glass transition temperature (Tg) is preferably 30 to 80 ° C, and particularly preferably 40 to 65 ° C. In addition, a glass transition temperature (Tg) can be measured with a differential calorimeter (DSC), and specifically, is measured by the method described in the examples. Those skilled in the art can control the glass transition temperature by controlling the resin composition.

  The weight average molecular weight (Mw) of the amorphous resin is not particularly limited, but is preferably 2,000 to 150,000, and more preferably 10,000 to 100,000.

  As the amorphous resin, a conventionally known amorphous resin in this technical field can be used, and among them, an amorphous polyester resin or a vinyl resin is preferable, and these resins may be mixed and used. Among these, the amorphous resin preferably contains a vinyl resin, preferably contains a styrene resin, and more preferably contains a styrene acrylic resin, from the viewpoint of excellent environmental stability of the charge amount. preferable. Vinyl resins (especially styrene acrylic resins) have less polar functional groups and lower hygroscopicity than amorphous polyester resins, so they can be transferred even in harsh environments such as high-temperature and high-humidity environments. It becomes good. Therefore, it can have good transferability under any environment. The content of the styrene acrylic resin in the amorphous resin is not particularly limited. As described above, from the viewpoint of obtaining good transferability in any environment, the content of the styrene acrylic resin is preferably 10 to 100% by mass with respect to the total amount of the amorphous resin, and 20 to 100. More preferably, it is mass%.

  Moreover, the amorphous resin may be in a state where several types are mixed. As an example of the amorphous resin other than the styrene acrylic resin, an amorphous polyester resin or a hybrid amorphous polyester resin is preferably exemplified. These amorphous resins can be obtained by a known synthesis method or commercially available. Further, when the toner base particles have a core-shell structure, the styrene acrylic resin and the crystalline polyester resin constitute the core portion from the viewpoint of controllability of the dispersion state of the crystalline polyester resin in the toner particles and charging characteristics, Preferably, the crystalline resin constitutes the shell layer, the styrene acrylic resin and the crystalline polyester resin constitute the core portion, and the amorphous polyester resin or the hybrid amorphous polyester resin constitutes the shell layer. More preferably, the styrene acrylic resin and the crystalline polyester resin constitute the core portion, and the hybrid amorphous polyester resin further constitutes the shell layer.

<Styrene resin and styrene acrylic resin (styrene acrylic copolymer)>
In the present specification, the styrene resin represents at least a constituent unit derived from styrene. The styrene resin is obtained by performing polymerization using at least a styrene monomer.

  Moreover, in this specification, a styrene acrylic resin represents what has a structural unit derived from a styrene at least and a structural unit derived from a (meth) acrylic acid ester monomer. The styrene acrylic resin is obtained by performing polymerization using at least a styrene monomer and a (meth) acrylic acid ester monomer.

  The styrene monomer and the (meth) acrylic acid ester monomer are the same as those described in the column of the styrene acrylic polymerization segment.

  The styrene acrylic resin may have a structural unit derived from a general vinyl monomer in addition to the structural unit derived from styrene and the structural unit derived from a (meth) acrylic acid ester monomer. Although the vinyl monomer which can be used is illustrated below, it is not limited to these.

(1) Olefins Ethylene, propylene, isobutylene, etc. (2) Vinyl esters Vinyl propionate, vinyl acetate, vinyl benzoate, etc. (3) Vinyl ethers Vinyl methyl ether, vinyl ethyl ether, etc. (4) Vinyl ketones Vinyl methyl ketone, Vinyl ethyl ketone, vinyl hexyl ketone, etc. (5) N-vinyl compounds N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc. (6) Other vinyl compounds such as vinyl naphthalene, vinyl pyridine, acrylonitrile, methacrylo Acrylic acid or methacrylic acid derivatives such as nitrile and acrylamide.

  A vinyl monomer having a carboxy group can also be used. Specific examples thereof include vinyl monomers having a carboxy group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, and itaconic acid monoalkyl ester. It is done. Among these, acrylic acid or methacrylic acid is preferable.

  Furthermore, it is also possible to produce a resin having a crosslinked structure using a polyfunctional vinyl monomer.

  These vinyl monomers can be used alone or in combination of two or more.

  Although content of the structural unit derived from styrene in a styrene acrylic resin is not specifically limited, 40-95 mass% is preferable with respect to the whole monomer, and 50-80 mass% is more preferable. Moreover, 5-60 mass% is preferable with respect to the whole monomer, and, as for content of the structural unit derived from a (meth) acrylic acid ester monomer, 20-50 mass% is more preferable.

  The molecular weight of the styrene acrylic resin is preferably 2,000 to 1,000,000 in terms of weight average molecular weight (Mw). Setting the weight average molecular weight (Mw) of the styrene acrylic resin in the above range is effective in suppressing the occurrence of the offset phenomenon.

  The content of the styrene acrylic resin in the binder resin is preferably 50 to 95% by mass from the viewpoint of achieving both suppression of gloss temperature dependency and low-temperature fixability.

<Hybrid amorphous polyester resin>
In the toner according to an embodiment of the present invention, the amorphous resin is a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. It is preferable to contain. More specifically, the amorphous resin is a hybrid amorphous polyester resin having a graft copolymer structure in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. It is preferable to contain. By including such a hybrid amorphous polyester resin, the compatibility of the shell portion with the vinyl resin is appropriately increased while maintaining compatibility between the core portion and the shell portion. Therefore, adhesion of the shell part to the core part becomes easier, and the heat-resistant storage property of the toner is further improved.

  The amorphous polyester polymer segment is a portion derived from a known polyester resin obtained by a polycondensation reaction with a polyvalent carboxylic acid component and a polyhydric alcohol component similar to the amorphous polyester resin, and is a differential scanning of the toner. In calorimetry (DSC), it refers to a polymer segment in which no clear endothermic peak is observed.

  Examples of the polyvalent carboxylic acid component include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, and dodecanedicarboxylic acid. , Fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucoic acid, phthalic acid , Isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid , Diphenylacetic acid, diphenyl-p, p'- Dicarboxylic acids such as carboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid; trimellitic acid, pyromellitic acid, naphthalene Examples include tricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid. These polyvalent carboxylic acids can be used alone or in admixture of two or more. Among these, it is preferable to use aliphatic unsaturated dicarboxylic acids such as fumaric acid, maleic acid, and mesaconic acid, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, succinic acid, and trimellitic acid.

  Examples of the polyhydric alcohol component include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, decanediol, dodecanediol, bisphenol A ethylene oxide adduct, and bisphenol A propylene oxide adduct. And dihydric alcohols such as glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, tetraethylol benzoguanamine and the like. These polyhydric alcohol components can be used alone or in admixture of two or more. Among these, divalent alcohols such as bisphenol A ethylene oxide adduct and bisphenol A propylene oxide adduct are preferable.

  The amorphous polyester polymer segment is not particularly limited as long as it is defined above. For example, for a resin having a structure in which other components are copolymerized on the main chain of an amorphous polyester polymerization segment and a resin having a structure in which an amorphous polyester polymerization segment is copolymerized on a main chain composed of other components, If the toner containing the resin does not have a clear endothermic peak as described above, the resin corresponds to the hybrid amorphous polyester resin having an amorphous polyester polymer segment in the present invention.

  The content of the amorphous polyester polymer segment is preferably 75 to 98% by mass with respect to the total amount of the hybrid amorphous polyester resin. In addition, the structural component and content rate of each segment in hybrid amorphous polyester resin can be specified by NMR measurement and methylation reaction Py-GC / MS measurement, for example.

  The hybrid amorphous polyester resin contains a vinyl polymer segment containing a styrene-derived structural unit in addition to the amorphous polyester polymer segment. The vinyl polymerized segment is not particularly limited as long as it contains a styrene-derived structural unit, but a styrene- (meth) acrylic acid ester polymerized segment (styrene acrylic polymerized segment) is preferable in consideration of plasticity during heat fixing.

  The styrene acrylic polymerization segment is formed by addition polymerization of at least a styrene monomer and a (meth) acrylic acid ester monomer. Specific examples of the monomer capable of forming the styrene-acrylic polymer segment include the same monomers as those described for the styrene-acrylic resin, and thus the description thereof is omitted here.

  The content of the structural unit derived from styrene in the vinyl polymerization segment is preferably 40 to 95% by mass with respect to the total amount of the vinyl polymerization segment. Moreover, the content rate of the structural unit derived from the (meth) acrylic acid ester monomer in the vinyl polymerization segment is preferably 5 to 60% by mass with respect to the total amount of the vinyl polymerization segment.

  Furthermore, it is preferable that the vinyl polymerized segment is obtained by addition polymerization of a compound for chemically bonding to the amorphous polyester polymerized segment in addition to the styrene monomer and the (meth) acrylic acid ester monomer. Specifically, it is preferable to use a compound which is ester-bonded to a hydroxyl group [—OH] derived from a polyhydric alcohol component or a carboxyl group [—COOH] derived from a polyvalent carboxylic acid component contained in the crystalline polyester polymerization segment. . Therefore, the vinyl polymerization segment can be addition-polymerized with respect to styrene and (meth) acrylic acid ester monomers, and further polymerize a compound having a carboxyl group [—COOH] or a hydroxyl group [—OH]. This is preferable.

  Examples of such compounds include compounds having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, cinnamic acid, fumaric acid, maleic acid monoalkyl ester, itaconic acid monoalkyl ester; 2-hydroxy Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate And compounds having a hydroxyl group such as polyethylene glycol mono (meth) acrylate.

  As for the content rate of the structural unit derived from the said compound in a vinyl polymerization segment, 0.5-20 mass% is preferable with respect to the whole quantity of a vinyl polymerization segment.

  The method for forming the styrene acrylic polymer segment is not particularly limited, and examples thereof include a method of polymerizing a monomer using a known oil-soluble or water-soluble polymerization initiator. Specific examples of the polymerization initiator are the same as those described in the section of the hybrid crystalline polyester resin.

  The content of the vinyl polymerization segment is preferably 2 to 25% by mass in the hybrid amorphous polyester resin.

  As a method for producing the hybrid amorphous polyester resin, an existing general scheme can be used. The following three methods are listed as typical methods.

(1) A method for producing a hybrid amorphous polyester resin by polymerizing a vinyl polymer segment in advance and performing a polymerization reaction to form an amorphous polyester polymer segment in the presence of the vinyl polymer segment (2) Amorphous A method of producing a hybrid amorphous polyester resin by forming a crystalline polyester polymerization segment and a vinyl polymerization segment, respectively, and combining them (3) Amorphous polyester polymerization segment is previously polymerized, A method for producing a hybrid amorphous polyester resin by performing a polymerization reaction for forming a vinyl polymer segment in the presence of a polyester polymer segment.

≪Colorant≫
Each toner contains a colorant corresponding to each color as necessary.

  The content of each colorant is preferably 1 to 30 parts by mass and more preferably 3 to 20 parts by mass with respect to 100 parts by mass of the toner particles. Also, within such a range, color reproducibility of the image can be ensured.

  Hereinafter, the types of colorants for each color will be described.

  As a colorant (pigment) used for each toner (excluding CL), carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used. As carbon black, channel black, furnace black, acetylene black, Thermal black, lamp black, etc. are used. Magnetic materials include ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, compounds of ferromagnetic metals such as ferrite and magnetite, alloys that do not contain ferromagnetic metals but exhibit ferromagnetism by heat treatment, For example, a kind of alloy called Heusler alloy such as manganese-copper-aluminum and manganese-copper-tin, chromium dioxide, and the like can be used.

  Examples of the black colorant (pigment) used for the black toner (K) include carbon black such as furnace black, channel black, acetylene black, thermal black, and lamp black, and magnetic powder such as magnetite and ferrite. .

  Examples of the magenta or red colorant (pigment) used in the magenta toner (M) are C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48; 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 150, C.I. I. Pigment red 166, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 222, C.I. I. Pigment red 238 and the like.

  Examples of the colorant (pigment) for orange or yellow used for yellow toner (Y) and the like include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. And CI Pigment Yellow 185.

  Further, as a colorant (pigment) for green or cyan used for cyan toner (C), C.I. I. Pigment blue 15, C.I. I. Pigment blue 15; 2, C.I. I. Pigment blue 15; 3, C.I. I. Pigment blue 15; 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 60, C.I. I. Pigment blue 62, C.I. I. Pigment blue 66, C.I. I. And CI Pigment Green 7.

  As the white colorant (pigment) used in the white toner (W), both inorganic pigments and organic pigments can be used. Specifically, examples of white inorganic pigments include heavy calcium carbonate, light calcium carbonate, titanium oxide (titanium dioxide), aluminum hydroxide, titanium white, talc, calcium sulfate, barium sulfate, zinc oxide, and magnesium oxide. , Magnesium carbonate, amorphous silica, colloidal silica, white carbon, kaolin, calcined kaolin, delaminated kaolin, aluminosilicate, sericite, bentonite, smectite and the like. Examples of the white organic pigment include polystyrene resin particles and urea formalin resin particles. Moreover, the white pigment which has a hollow structure, for example, a hollow resin particle, a hollow silica, etc. are mentioned. From the viewpoint of chargeability and concealability, the white colorant (pigment) is preferably titanium oxide. Titanium oxide can use any crystal structure such as anatase type, rutile type and brookite type.

  The metallic colorant (pigment) used in the metallic toner (ME) means a material capable of obtaining a metallic tone, and not only a conductive metallic material but also a non-metallic material, and a non-metallic material. A conductive material is also included. Examples of the metallic colorant (pigment) include aluminum pigment (aluminum powder; aluminum or its alloy powder), bronze powder, pearl pigment, and the like.

  These colorants (pigments) can be used alone or in combination of two or more as required.

  Further, the size of the colorant (particle) is not particularly limited, but the volume-based median diameter is preferably 10 to 1000 nm, more preferably 50 to 500 nm, and particularly preferably 80 to 300 nm. . Within such a range, high color reproducibility can be obtained, and it is preferable in that it is suitable for forming a small diameter toner required for high image quality. The volume-based median diameter of the colorant (particle) can be measured using, for example, a Microtrac (registered trademark, hereinafter the same) particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.).

≪Release agent≫
The toner particles of the colorant-containing toner of each color used in the present invention each include a release agent (wax).

  Examples of the release agent include hydrocarbon waxes such as low molecular weight polyethylene wax, low molecular weight polypropylene wax, Fischer-Tropsch wax, microcrystalline wax, and paraffin wax, carnauba wax, pentaerythritol behenate, and behenyl behenate. And ester waxes such as behenyl citrate. These can be used alone or in combination of two or more.

  The content of the release agent is preferably 2 to 20% by mass, more preferably 3 to 18% by mass, and particularly preferably 5 to 15% by mass with respect to the total amount of the binder resin.

  Further, the melting point of the release agent is preferably 50 to 95 ° C. from the viewpoints of low-temperature fixability and releasability of the toner in the electrophotographic system.

≪Charge control agent≫
Each toner may contain other internal additives as necessary. Examples of such an internal additive include a charge control agent. Examples of charge control agents include metal complexes of salicylic acid derivatives with zinc or aluminum (salicylic acid metal complexes), calixarene compounds, organic boron compounds, and fluorine-containing quaternary ammonium salt compounds.

  The content ratio of the charge control agent is usually preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the binder resin in the toner.

≪Toner (matrix) particle morphology≫
The toner (base material) particles may have a so-called single layer structure or a core-shell structure (a form in which a resin that forms a shell layer is aggregated and fused on the surface of the core particles). There may be. Toner (base) particles having a core-shell structure include resin regions (shells) having a relatively high glass transition temperature on the surface of resin particles (core particles) containing a colorant, a release agent and the like and having a relatively low glass transition temperature. A layer having a layer) is preferable. The core-shell structure is not limited to the structure in which the shell layer completely covers the core particles. For example, the shell layer does not completely cover the core particles, and the core particles are exposed in some places. Including those that are.

  The form of the toner (base material) particles (cross-sectional structure of the core-shell structure, etc.) can be confirmed using a known means such as a transmission electron microscope (TEM) or a scanning probe microscope (SPM). Is possible.

≪Average circularity of toner (base material) particles≫
From the viewpoint of improving the low-temperature fixability, the average circularity of the toner (base material) particles is preferably 0.920 to 1.000, and more preferably 0.940 to 0.995. Here, the average circularity is a value measured using “FPIA-2100” (manufactured by Sysmex). Specifically, the toner (base material) particles are moistened in an aqueous surfactant solution, subjected to ultrasonic dispersion for 1 minute, dispersed, and then using “FPIA-2100” in the measurement condition HPF (high magnification imaging) mode. The measurement is performed at an appropriate concentration of 4000 detected HPFs. The circularity is calculated by the following formula.

Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)
The average circularity is an arithmetic average value obtained by adding the circularity of each particle and dividing by the total number of particles measured.

≪Toner (base material) particle size≫
Regarding the particle diameter of the toner (base material) particles, the volume-based median diameter (D50) is preferably 3 to 10 μm. By setting the volume-based median diameter within the above range, reproducibility of fine lines and high-quality photographic images can be achieved, and toner consumption can be reduced as compared to the case of using large-diameter toner. be able to. Also, toner fluidity can be secured. Here, the volume-based median diameter (D50) of toner (base material) particles is measured using, for example, a device in which a computer system for data processing is connected to “Coulter Multisizer 3” (manufactured by Beckman Coulter, Inc.). Can be calculated.

  The volume-based median diameter of toner (base material) particles is controlled by the concentration of the aggregating agent, the amount of solvent added, the fusing time, and the composition of the resin component, etc. can do.

≪External additive≫
Each toner preferably contains particles such as known inorganic particles and organic particles, a lubricant, and the like as external additives on the surface of the toner base particles from the viewpoint of improving charging performance, fluidity, and cleaning properties. Various external additives may be used in combination. Examples of the particles include inorganic oxide particles such as silica particles, alumina particles and titania particles, inorganic stearate compound particles such as aluminum stearate particles and zinc stearate particles, or strontium titanate particles and zinc titanate particles. And inorganic titanic acid compound particles. In addition, as the lubricant, zinc stearate, such as zinc, aluminum, copper, magnesium, calcium, zinc oleate, manganese, iron, copper, magnesium, etc., zinc palmitate, copper, magnesium, calcium, etc. And salts of higher fatty acids such as salts, zinc of linoleic acid, salts of calcium, etc., zinc of ricinoleic acid, salts of calcium, etc. These external additives may be subjected to surface treatment with a silane coupling agent, a titanium coupling agent, a higher fatty acid, silicone oil, or the like from the viewpoint of heat-resistant storage stability and environmental stability. The external additives can be used alone or in combination of two or more.

  Among these, inorganic oxide particles such as silica particles (spherical silica), alumina particles, and titania particles are preferably used as the external additive.

  The amount of the external additive added (the total amount when two or more types are used) is preferably 0.05 to 5% by mass, more preferably 100% by mass based on the total mass of the toner particles including the external additive. It is 0.1-3 mass%.

  The particle size of the external additive is not particularly limited, but particles such as inorganic fine particles having a number average primary particle size of about 2 to 800 nm and organic fine particles having a number average primary particle size of about 10 to 2000 nm are preferable. In this specification, “number average primary particle diameter” is a value obtained by binarizing a scanning electron micrograph of external additive particles, calculating a horizontal ferret diameter for 10,000 particles, and taking the average. Say.

[Toner Production Method]
Hereinafter, a method for producing the electrostatic latent image developing toner will be described.

  The method for producing the toner is not particularly limited, and examples thereof include known methods such as a kneading and pulverizing method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method.

  Among these, from the viewpoint of controllability of the peak height ratio W, uniformity of particle diameter, controllability of the shape, and ease of forming the core-shell structure, it is preferable to employ an emulsion aggregation method. Hereinafter, the emulsion aggregation method will be described.

≪Emulsion aggregation≫
In the emulsion aggregation method, a dispersion of binder resin particles (hereinafter, also referred to as “binder resin particles”) dispersed by a surfactant or a dispersion stabilizer is used in some cases as release agent particles (hereinafter, “ The toner is mixed with the dispersion liquid of the release agent particles) and the colorant particles, aggregated until a desired particle size is obtained, and further fused between the binder resin particles, thereby controlling the shape. A method for producing particles.

  In addition, toner particles having a core-shell structure can be obtained by an emulsion aggregation method. Specifically, the toner particles having a core-shell structure are obtained by first aggregating the binder resin particles for core particles and the colorant (by fusing). ) To produce core particles, and then the binder resin particles for the shell layer are added to the dispersion of the core particles, and the binder resin particles for the shell layer are aggregated and fused on the surface of the core particles. It can be obtained by forming a shell layer covering the surface of the core particle.

  When the toner is produced by the emulsion aggregation method, the following preferred forms are mentioned, although not particularly limited.

  A method for producing a toner according to a preferred embodiment includes a step of preparing a crystalline polyester resin particle dispersion, a styrene acrylic resin particle dispersion, and optionally a hybrid amorphous polyester resin particle dispersion (hereinafter also referred to as a preparation step) ( a) a step of mixing a crystalline polyester resin particle dispersion and a styrene acrylic resin particle dispersion and aggregating and fusing them to obtain a core particle dispersion (hereinafter also referred to as agglomeration and fusing step) (b) And a step (c) of mixing the core particle dispersion and the hybrid amorphous polyester resin particle dispersion and aggregating and fusing them to obtain a toner particle dispersion.

  Hereinafter, although each process (a)-(c) and each process (d)-(f) arbitrarily performed besides these processes are explained in full detail, it is not restrict | limited to the following methods.

(A) Preparation Step Step (a) includes a step of preparing a crystalline polyester resin particle dispersion, a styrene acrylic resin particle dispersion, and optionally a hybrid amorphous polyester resin particle dispersion, and if necessary And a colorant dispersion preparation step.

(A-1) Styrene acrylic resin particle dispersion preparation step The styrene acrylic resin particle dispersion is prepared by, for example, a method of performing a dispersion treatment in an aqueous medium without using a solvent, or dissolving a styrene acrylic resin in a solvent such as ethyl acetate. For example, a method of performing a solvent removal treatment after emulsifying and dispersing the solution in an aqueous medium using a disperser may be used. Preferably, a styrene acrylic resin particle dispersion is prepared by dispersing a styrene acrylic resin in an aqueous medium.

  The aqueous medium refers to a medium having a water content of 50% by mass or more. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Of these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, butanol and the like, which are organic solvents that do not dissolve the resin, are particularly preferable. Preferably only water is used as the aqueous medium.

  Furthermore, a dispersion stabilizer may be dissolved in the aqueous medium, and a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets.

  As the dispersion stabilizer, a known one can be used. For example, it is preferable to use a material that is soluble in acid or alkali, such as tricalcium phosphate, or from an environmental point of view, it may be an enzyme. It is preferable to use a decomposable one.

  As the surfactant, known anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants can be used.

  Examples of the resin fine particles for improving dispersion stability include polymethyl methacrylate resin fine particles, polystyrene resin fine particles, and polystyrene-acrylonitrile resin fine particles.

  The dispersion treatment is preferably performed under stirring, and can be performed using mechanical energy, and the disperser is not particularly limited, and includes a homogenizer, a low-speed shear disperser, and a high-speed shear type. Examples include a disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser, a high-pressure impact disperser, an optimizer, and an emulsifier disperser.

  The method for producing the styrene acrylic resin is not particularly limited, and known methods such as bulk polymerization method, solution polymerization method, emulsion polymerization method, miniemulsion method, dispersion polymerization method using a known oil-soluble or water-soluble polymerization initiator. The method of superposing | polymerizing by the polymerization method of this is mentioned. You may use well-known chain transfer agents, such as n-octyl mercaptan, as needed. Among them, it is preferable to use an emulsion polymerization method in which a resin monomer is added to an aqueous medium together with a polymerization initiator and the monomer is polymerized to obtain a dispersion of resin particles.

  In the emulsion polymerization method, the following seed polymerization is preferable. Specifically, a monomer for obtaining a styrene acrylic resin (styrene monomer, (meth) acrylic acid ester monomer, etc.) is added to an aqueous medium together with a polymerization initiator to polymerize the basic particles. obtain. Next, a radical polymerizable monomer and a polymerization initiator for obtaining a styrene acrylic resin are added to the dispersion liquid in which the resin particles are dispersed, and the radical polymerizable monomer is seed-polymerized to the basic particles. It is preferable to use the technique to do.

  Also, for example, in the case of carrying out a polymerization reaction in three stages, a dispersion of resin particles is prepared by first-stage polymerization, and a resin monomer and a polymerization initiator are further added to the dispersion, whereby second-stage polymerization is performed. Let A resin monomer and a polymerization initiator are further added to the dispersion prepared by the second stage polymerization to carry out the third stage polymerization. At the second stage and third stage polymerization, the resin particles in the dispersion produced by the previous polymerization can be used as seeds to further polymerize the monomer newly added to the resin particles. The particle size of the resin particles can be made uniform. In addition, by using different monomers in the polymerization reaction at each stage, the resin particle structure can also be a multilayer structure, and it is easy to obtain resin particles having desired characteristics.

  At this stage, a release agent may be contained. In this case, in order to improve the dispersibility of the wax, it is preferable to add the wax and the polymerizable monomer (mixture) to the aqueous medium, and then stir with applying mechanical energy. It is preferable to use a disperser such as a disperser, a high-speed shear disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser, a high-pressure impact disperser, or an optimizer. Commercially available products can be used as the disperser, for example, “CLEARMIX (registered trademark)” (manufactured by M Technique Co., Ltd.), HJP30006 (manufactured by Sugino Machine Co., Ltd.), ultrasonic homogenizer US-150T. (Nippon Seiki Seisakusho) etc. can be used.

  In dispersing, it is preferable to heat the solution. Although heating conditions are not specifically limited, Usually, it is about 60-100 degreeC.

(Polymerization initiator)
As the polymerization initiator that can be used in the polymerization reaction, known ones can be used. For example, persulfates such as ammonium persulfate, sodium persulfate, potassium persulfate, and the like, 2,2′-azobis (2-aminodipropane) ) Hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 4,7'-azobis-4-cyanovaleric acid, poly (tetraethylene glycol-2,2'-azobisisobutyrate) And azo compounds such as hydrogen peroxide and peroxides such as hydrogen peroxide.

  The addition amount of the polymerization initiator varies depending on the target molecular weight and molecular weight distribution, but specifically, it may be in the range of 0.1 to 5.0% by mass with respect to the addition amount of the polymerizable monomer. it can.

(Chain transfer agent)
In the polymerization reaction, a chain transfer agent can be added from the viewpoint of controlling the molecular weight of the resin particles. Examples of chain transfer agents that can be used include, for example, mercaptans such as octyl mercaptan, dodecyl mercaptan and t-dodecyl mercaptan; n-octyl-3-mercaptopropionate, stearyl-3-mercaptopropionate and the like. Mercaptopropionic acid; and styrene dimer can be used. These can be used alone or in combination of two or more.

  Although the addition amount of a chain transfer agent changes with target molecular weights or molecular weight distribution, it can be in the range of 0.1-5.0 mass% with respect to the addition amount of a polymerizable monomer.

(Surfactant)
During the polymerization reaction, a surfactant can be added from the viewpoint of preventing aggregation of the resin particles in the dispersion and maintaining a good dispersion state.

  Examples of the surfactant include cationic surfactants such as dodecyl ammonium bromide and dodecyl trimethyl ammonium bromide, sodium stearate, sodium lauryl sulfate (sodium dodecyl sulfate), sodium polyoxyethylene dodecyl ether sulfate, sodium dodecyl benzene sulfonate, and the like. Known anionic surfactants, nonionic surfactants such as dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, and the like can be used. One of these may be used alone or in combination of two or more.

  The particle diameter of the styrene acrylic resin particles (oil droplets) in the styrene acrylic resin particle dispersion prepared in this way is a volume-based median diameter, preferably 60 to 1000 nm, and more preferably 80 to 500 nm. The volume-based median diameter is measured by the method described in the examples. The volume-based median diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

(A-2) Crystalline polyester resin particle dispersion liquid preparation step As a method of dispersing the crystalline polyester resin in the aqueous medium, the crystalline polyester resin is dissolved or dispersed in an organic solvent (solvent) to obtain an oil phase liquid. And an oil phase liquid is dispersed in an aqueous medium by phase inversion emulsification or the like to form oil droplets in a state of being controlled to a desired particle size, and then the organic solvent is removed.

  The organic solvent (solvent) used for the preparation of the oil phase liquid is preferably one having a low boiling point and low solubility in water from the viewpoint of easy removal after the formation of oil droplets. Specific examples include methyl acetate, ethyl acetate, methyl ethyl ketone, isopropyl alcohol, methyl isobutyl ketone, toluene, xylene and the like. These can be used alone or in combination of two or more.

  The amount of the organic solvent (solvent) used (when two or more types are used, the total amount used) is preferably 1 to 600 parts by mass, more preferably 10 to 500 parts by mass with respect to 100 parts by mass of the resin.

  Furthermore, ammonia, sodium hydroxide, or the like may be added to the oil phase liquid in order to ionically dissociate the carboxyl group and stably emulsify the aqueous phase to facilitate the emulsification.

  The amount of the aqueous medium used is preferably 50 to 2,000 parts by mass and more preferably 100 to 1,000 parts by mass with respect to 100 parts by mass of the oil phase liquid. By making the usage-amount of an aqueous medium into said range, an oil phase liquid can be emulsified and dispersed to a desired particle size in an aqueous medium.

  A dispersion stabilizer may be dissolved in the aqueous medium, and a surfactant or resin fine particles may be added for the purpose of improving the dispersion stability of the oil droplets. Specific examples and preferred examples of the dispersion stabilizer, surfactant and resin fine particles are as described in the above section (a-1).

  Such emulsification and dispersion of the oil phase liquid can be performed using mechanical energy, and the disperser for performing the emulsification and dispersion is not particularly limited. Examples thereof include an ultrasonic disperser, a friction disperser, a high-pressure jet disperser, an ultrasonic disperser such as an ultrasonic homogenizer, and a high-pressure impact disperser optimizer.

  The removal of the organic solvent after the formation of the oil droplets is performed by gradually heating the entire dispersion in a state where the crystalline polyester resin particles / amorphous resin particles are dispersed in the aqueous medium in a stirring state to a certain temperature. After giving strong stirring in the region, it can be carried out by an operation such as desolvation. Alternatively, it can be removed while reducing the pressure using an apparatus such as an evaporator.

  The average particle diameter (oil droplet) of the crystalline polyester resin particles (oil droplets) in the prepared crystalline polyester resin particle dispersion is preferably 60 to 1000 nm in terms of volume-based median diameter, and 80 More preferably, it is ˜500 nm. In addition, an average particle diameter is measured by the method as described in an Example. The average particle size of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

(A-3) Hybrid Amorphous Polyester Resin Particle Dispersion Preparation Step The hybrid amorphous polyester resin particle dispersion preparation step synthesizes a hybrid amorphous polyester resin that constitutes toner particles. This is a step of preparing a dispersion of hybrid amorphous polyester resin particles by dispersing the resin in a fine particle form in an aqueous medium.

  Since the method for producing the hybrid amorphous polyester resin is as described above, details are omitted.

  The hybrid amorphous polyester resin particle dispersion is prepared by, for example, a method of performing dispersion treatment in an aqueous medium without using a solvent (A), or by dissolving or dispersing the hybrid amorphous polyester resin in an organic solvent (solvent). A method of removing an organic solvent after preparing an oil phase liquid, dispersing the oil phase liquid in an aqueous medium by phase inversion emulsification or the like to form oil droplets in a state of being controlled to a desired particle size ( I).

  The aqueous medium and the dispersion method in the method (a) are as described in the column (a-1). The details of the method (ii) are as described in the column (a-2) above.

  The particle size of the hybrid amorphous polyester resin particles (oil droplets) in the hybrid amorphous polyester resin particle dispersion thus prepared is preferably a volume-based median diameter of 60 to 1000 nm, more preferably 80 to 500 nm. preferable. The volume-based median diameter is measured by the method described in the examples. The volume-based median diameter of the oil droplets can be controlled by the magnitude of mechanical energy during emulsification dispersion.

(A-4) Colorant particle dispersion preparation process A colorant is dispersed in an aqueous medium to prepare a colorant particle dispersion.

  In preparing the colorant particle dispersion, the above-mentioned surfactant can be added in order to improve the dispersion stability of the colorant particles. Further, the mechanical energy described above can be used for distributed processing.

  The colorant particles in the dispersion preferably have a volume-based median diameter in the range of 10 to 300 nm, more preferably in the range of 100 to 200 nm, and still more preferably in the range of 100 to 150 nm. .

(B) Aggregation / fusion process The prepared styrene acrylic resin particle dispersion and, if necessary, the colorant particle dispersion are mixed to aggregate each of the styrene acrylic resin particles and the colorant particles in an aqueous medium. . Furthermore, after heating a liquid mixture, each particle | grain can be fuse | melted by adding a crystalline polyester resin particle dispersion liquid, and a core particle (core part) can be formed. At the time of agglomeration and fusion, a flocculant having a critical agglomeration concentration or higher is added, and the mixture is heated to a temperature higher than the glass transition temperature (Tg) of the styrene acrylic resin to promote aggregation and fusion.

  More specifically, after mixing the styrene acrylic resin particle dispersion and, if necessary, the colorant particle dispersion, a base such as an aqueous sodium hydroxide solution is added to the mixture in advance to impart cohesion. It is preferable to adjust the pH to 9-12.

  Next, it is preferable to add a colorant particle dispersion as necessary and add the flocculant while stirring at 25 to 35 ° C. for 5 to 15 minutes. The amount of the flocculant used is preferably 5 to 20% by mass with respect to the total solid content of the binder resin particles and the colorant particles. The flocculant that can be used is not particularly limited, and examples thereof include alkali metal salts and metal salts such as Group 2 metal salts.

  Examples of the metal salt include monovalent metal salts such as sodium chloride, potassium chloride and lithium chloride, divalent metal salts such as calcium chloride, magnesium chloride, copper sulfate and magnesium sulfate, and trivalent metals such as iron and aluminum. Examples include salts. Of these, divalent metal salts are preferred because they can be aggregated in a smaller amount.

  In the flocculation step, it is preferable that the standing time (time until heating is started) to be left after adding the flocculant is as short as possible. That is, after adding the flocculant, it is preferable to start heating the dispersion for aggregation as soon as possible. The standing time is usually 30 minutes or less (lower limit 0 minute), preferably 10 minutes or less.

  Further, in the aggregation step, it is preferable to quickly raise the temperature by heating after adding the aggregating agent, and the rate of temperature rise is preferably 0.8 ° C./min or more. The upper limit of the heating rate is not particularly limited, but is preferably 15 ° C./min or less from the viewpoint of suppressing the generation of coarse particles due to rapid progress of fusion.

  The charging temperature of the crystalline polyester resin dispersion (first-stage dispersion charging temperature) is not particularly limited, but is preferably 70 to 90 ° C, and more preferably 75 to 85 ° C. Further, the particle size (the first-stage dispersion charged particle size) when the crystalline polyester resin dispersion is charged is preferably from 5.0 μm or less before the start of particle size growth to 4 to 4 before the start of particle size growth. More preferably, it is 5 μm or less.

  Further, after adding the crystalline polyester resin dispersion, it is important to continue the fusion by maintaining the temperature for a certain time, preferably until the volume-based median diameter is 4.5 to 7.0 μm. .

(C) Step of mixing the core particle dispersion and the hybrid amorphous polyester resin particle dispersion and aggregating and fusing them to obtain a toner particle dispersion Next, the aqueous solution of the hybrid amorphous polyester resin particles forming the shell portion The dispersion is further added to agglomerate and fuse the hybrid amorphous polyester resin forming the shell portion on the surface of the binder resin particles (core particles) obtained above. Thereby, a binder resin having a core-shell structure is obtained (shell forming step). When the size of the aggregated particles reaches a target size, a salt such as an aqueous sodium chloride solution is added to stop the aggregation. Thereafter, the heat treatment of the reaction system may be further performed until the aggregation and fusion of the shell part on the surface of the core particle is further strengthened and the shape of the particle becomes a desired shape (second aging step). This second ripening step may be performed until the average circularity of the toner particles having the core-shell structure is within a desired average circularity (preferably within the above preferable range).

  As a result, particle growth (aggregation of crystalline resin particles, styrene acrylic resin particles, hybrid amorphous polyester resin, and, if necessary, colorant particles) and fusion (disappearance of the interface between particles) are effective. The durability of the toner particles finally obtained can be improved.

  Further, instead of the hybrid amorphous polyester resin, a styrene acrylic resin may be used as the resin for the shell layer.

(D) Cooling Step This step is a step of cooling the toner particle dispersion. As a condition for the cooling treatment, it is preferable to cool at a cooling rate of 1 to 20 ° C./min. The specific method of the cooling treatment is not particularly limited, and examples include a method of cooling by introducing a refrigerant from the outside of the reaction vessel, a method of cooling by directly introducing cold water into the reaction system, and the like. it can.

(E) Filtration / Washing Step In this step, the toner particles are solid-liquid separated from the cooled dispersion of toner particles, and the toner cake obtained by solid-liquid separation (the toner particles in a wet state are aggregated in a cake form) This is a step of removing adhering substances such as a surfactant and an aggregating agent from the aggregate).

  The solid-liquid separation is not particularly limited, and a centrifugal separation method, a vacuum filtration method using Nutsche or the like, a filtration method using a filter press, or the like can be used.

(F) Drying step This step is a step of drying the washed toner cake, and can be performed according to a drying step in a generally-known method for producing toner particles.

  Specifically, examples of the dryer used for drying the toner cake include a spray dryer, a vacuum freeze dryer, and a vacuum dryer, and a stationary shelf dryer, a mobile shelf dryer, a fluidized bed, and the like. It is preferable to use a dryer, a rotary dryer, a stirring dryer or the like.

(G) External additive addition step This step is a step that is performed as necessary when an external additive is added to the toner particles.

  As an external additive mixing apparatus, a mechanical mixing apparatus such as a Henschel mixer, a coffee mill, or a sample mill can be used.

<Developer>
Each of the above color toners can be used as a magnetic or non-magnetic one-component developer, but may be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier includes magnetic particles made of conventionally known materials such as metals such as iron, ferrite and magnetite, and alloys of these metals with metals such as aluminum and lead. In particular, ferrite particles are preferable. Further, as the carrier, a coated carrier in which the surface of magnetic particles is coated with a coating agent such as a resin, a dispersion type carrier in which a magnetic fine powder is dispersed in a binder resin, or the like may be used.

  The volume average particle diameter of the carrier is preferably 20 to 100 μm, and more preferably 25 to 80 μm. The volume average particle diameter of the carrier can be typically measured by a laser diffraction type particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.

  The two-component developer can be produced by mixing the carrier and the toner using a mixing device. Examples of the mixing device include a Henschel mixer, a Nauter mixer, and a V-type mixer.

  The blending amount of the toner in producing the two-component developer according to the present invention is preferably 1 to 10% by mass with respect to 100% by mass in total of the carrier and the toner.

<Image forming method>
The image forming method of the first embodiment includes forming an image forming layer on a recording medium using toner for developing electrostatic latent images of a plurality of colors.

  For example, in a full-color image forming method using four types of toners of black toner (K), yellow toner (Y), magenta toner (M) and cyan toner (C), each of yellow, magenta, cyan and black A method using a four-cycle image forming apparatus comprising four types of color developing devices and one electrostatic latent image carrier (also referred to as “electrophotographic photosensitive member” or simply “photosensitive member”), Any color image forming method can be used, such as a method using a tandem type image forming apparatus in which an image forming unit having a color developing device for each color and an electrostatic latent image carrier is mounted for each color.

  As a color image forming method, an image forming method including a fixing step by a heat and pressure fixing method capable of applying pressure and heating can be preferably exemplified.

  Specifically, in this color image forming method, the toner is used, for example, an electrostatic latent image formed on a photoreceptor is developed to obtain a toner image, and this toner image is used as an image support. Then, the toner image transferred onto the image support is fixed on the image support by a contact heating type fixing process, whereby a printed matter on which a visible image is formed can be obtained.

  A suitable fixing method includes a so-called contact heating method. Examples of the contact heating method include a heat pressure fixing method, a heat roll fixing method, and a pressure contact heat fixing method in which fixing is performed by a rotating pressure member including a fixedly arranged heating body.

  In the fixing method of the hot roll fixing method, usually, an upper roller provided with a heat source inside a metal cylinder made of iron or aluminum whose surface is coated with fluororesin, etc., and a lower roller formed of silicone rubber or the like Is used.

  As the heat source, a linear heater is used, and the surface temperature of the upper roller is heated to about 120 to 200 ° C. by this heater. A pressure is applied between the upper roller and the lower roller, and the lower roller is deformed by this pressure, so that a so-called nip is formed in the deformed portion. The width of the nip is 1 to 10 mm, preferably 1.5 to 7 mm. The fixing linear velocity is preferably 40 mm / sec to 600 mm / sec.

(recoding media)
The recording medium (also referred to as recording material, recording paper, recording paper, etc.) may be a commonly used one, for example, as long as it holds a toner image formed by a known image forming method using an image forming apparatus or the like. It is not particularly limited. Examples of usable image supports include plain paper from thin paper to thick paper, high-quality paper, art paper, coated printing paper such as coated paper, commercially available Japanese paper and postcard paper, OHP Plastic films, fabrics, various resin materials used for so-called soft packaging, or resin films obtained by forming them into a film, labels, and the like.

  The effects of the present invention will be described using the following examples and comparative examples, but the present invention is not limited to these embodiments. In the examples, “parts” or “%” may be used, but “parts by mass” or “% by mass” is indicated unless otherwise specified. Unless otherwise specified, each operation is performed at room temperature (25 ° C.).

(Melting point (Tm) of crystalline polyester resin and glass transition temperature (Tg) of amorphous resin
The melting point (Tm) of the crystalline polyester resin and the glass transition temperature (Tg) of the amorphous resin were obtained using a differential scanning calorimeter (manufactured by Shimadzu Corporation: DSC-60A) in accordance with ASTM D3418. The temperature correction of the detection part of this apparatus (DSC-60A) was performed using the melting point of indium and zinc, and the heat of fusion of indium was used to correct the amount of heat. For the sample, an aluminum pan was used, an empty pan was set for control, the temperature was raised at a rate of temperature increase of 10 ° C / min, held at room temperature to 150 ° C for 5 minutes, and liquid nitrogen was used from 150 ° C to 0 ° C. The temperature was lowered at −10 ° C./min, held at 0 ° C. for 5 minutes, and heated again from 0 ° C. to 200 ° C. at 10 ° C./min. The analysis was performed from the endothermic curve during the second temperature increase, and the onset temperature was set to Tg for the amorphous resin and the peak top temperature of the endothermic peak was set to the melting point for the crystalline polyester resin.

(Volume-based median diameter of resin particles, colorant particles, etc.)
Volume-based median diameters of resin particles, colorant particles, release agents, etc. were measured with a laser diffraction / scattering particle size distribution measuring device (Microtrac particle size distribution measuring device “UPA-150” (manufactured by Nikkiso Co., Ltd.)). .

(Weight average molecular weight of resin (Mw))
The weight average molecular weight (Mw) of each resin contained in the binder resin was measured by a measurement method using the following gel permeation chromatography (GPC).

That is, using an apparatus “HLC-8220” (manufactured by Tosoh Corporation) and a column “TSKguardcolumn + TSKgelSuperHZM-M3 series” (manufactured by Tosoh Corporation), while maintaining the column temperature at 40 ° C., tetrahydrofuran (THF) was used as a carrier solvent at a flow rate. The flow was 0.2 mL / min. The measurement sample was dissolved in tetrahydrofuran so as to have a concentration of 1 mg / mL under dissolution conditions in which treatment was performed for 5 minutes using an ultrasonic disperser at room temperature (25 ° C.). Next, a sample solution is obtained by processing with a membrane filter having a pore size of 0.2 μm, and 10 μL of this sample solution is injected into the apparatus together with the above carrier solvent, and is detected using a refractive index detector (RI detector) and measured. The molecular weight distribution of the sample was calculated using a calibration curve measured using monodisperse polystyrene standard particles. As a standard polystyrene sample for calibration curve measurement, the molecular weights manufactured by Pressure Chemical are 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1 .1 x 10 ⁵ , 3.9 x 10 ⁵ , 8.6 x 10 ⁵ , 2 x 10 ⁶ , 4.48 x 10 ⁶ It was created. A refractive index detector was used as the detector.

<Manufacture of crystalline polyester resin 1>
The raw material monomer of the following styrene acrylic polymerization segment and the radical polymerization initiator were put into the dropping funnel.

Styrene 36.0 parts by mass n-butyl acrylate 13.0 parts by mass Acrylic acid 2.0 parts by mass Radical polymerization initiator (di-t-butyl peroxide) 7.0 parts by mass The polymer was placed in a four-necked flask equipped with a nitrogen gas introduction tube, a dehydration tube, a stirrer and a thermocouple, and heated to 170 ° C. to dissolve.

Tetradecanedioic acid 440 parts by mass 1,4-butanediol 153 parts by mass Next, the raw material monomer of the styrene acrylic polymerization segment was added dropwise over 90 minutes with stirring, and after aging for 60 minutes, under reduced pressure (8 kPa) The raw material monomer of the unreacted styrene-acrylic polymer segment was removed. The amount of the raw material monomer removed at this time was very small with respect to the raw material monomer charged as described above. Thereafter, 0.8 parts by mass of titanium tetrabutoxide (Ti (On-Bu) ₄ ) was added as a catalyst, the temperature was raised to 235 ° C., and the pressure was reduced under normal pressure (101.3 kPa) for 5 hours and further under reduced pressure. The reaction was performed at (8 kPa) for 1 hour. Subsequently, after cooling to 200 degreeC, it was made to react under reduced pressure (20 kPa) for 1 hour, and the crystalline polyester resin 1 was obtained. The obtained crystalline polyester resin 1 had a weight average molecular weight of 24,500 and a melting point of 75.5 ° C.

<Production of crystalline polyester resin particle dispersion 1>
100 parts by mass of the crystalline polyester resin 1 obtained above was dissolved in 400 parts by mass of ethyl acetate and mixed with 638 parts by mass of a 0.26% by mass sodium dodecyl sulfate aqueous solution prepared in advance. While stirring the obtained mixed solution, ultrasonic dispersion treatment was performed for 30 minutes at 300 μA with V-LEVEL using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusyo Co., Ltd.). Then, using a diaphragm vacuum pump V-700 (manufactured by BUCHI) while being heated to 40 ° C., ethyl acetate was completely removed while stirring for 3 hours under reduced pressure, to obtain a crystalline polyester resin particle dispersion 1 Was prepared. The crystalline polyester resin particles in the dispersion had a volume-based median diameter of 160 nm.

<Manufacture of Hybrid Amorphous Polyester Resin 1 for Shell>
A mixed liquid of the following styrene acrylic resin monomer, a monomer having a substituent that reacts with any of amorphous polyester resin and styrene acrylic resin, and a polymerization initiator was placed in a dropping funnel.

Styrene 80.0 parts by mass n-butyl acrylate 20.0 parts by mass Acrylic acid 10.0 parts by mass Di-t-butyl peroxide (polymerization initiator) 16.0 parts by mass In addition, a single amount of the following amorphous polyester resin The body was placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and heated to 170 ° C. to dissolve.

Bisphenol A propylene oxide 2-mol adduct 285.7 parts by mass Terephthalic acid 66.9 parts by mass Fumaric acid 47.4 parts by mass The mixture in the dropping funnel was added dropwise to the four-necked flask over 90 minutes with stirring. After aging for 60 minutes, unreacted monomers were removed under reduced pressure (8 kPa). Thereafter, 0.4 parts by mass of titanium tetrabutoxide (Ti (OBu) ₄ ) was added as an esterification catalyst, the temperature was raised to 235 ° C., and the pressure was reduced under normal pressure (101.3 kPa) for 5 hours and further under reduced pressure ( The reaction was performed at 8 kPa) for 1 hour. Subsequently, after cooling to 200 degreeC and reacting under reduced pressure (20 kPa), solvent removal was performed and the hybrid amorphous polyester resin for shells was obtained.

  The hybrid amorphous polyester resin for shells obtained above had a weight average molecular weight of 25,000 and a glass transition temperature of 60 ° C.

<Manufacture of hybrid amorphous resin particle dispersion 1 for shell>
100 parts by mass of the shell hybrid amorphous polyester resin 1 obtained above was dissolved in 400 parts by mass of ethyl acetate, and 638 parts by mass of a sodium dodecyl sulfate solution having a concentration of 0.26% by mass prepared in advance. Mixed. While stirring the obtained mixed solution, ultrasonic dispersion treatment was performed for 30 minutes at 300 μA with V-LEVEL using an ultrasonic homogenizer US-150T (manufactured by Nippon Seiki Seisakusyo Co., Ltd.). Then, using a diaphragm vacuum pump V-700 (manufactured by BUCHI) in a state heated to 40 ° C., ethyl acetate was completely removed while stirring for 3 hours under reduced pressure, and the solid content was 13.5 mass. % Amorphous polyester resin particle dispersion 1 for shell was prepared. The hybrid amorphous polyester resin particles for shells in the dispersion had a volume-based median diameter of 160 nm.

<Colorant dispersion (yellow)>
While stirring a solution obtained by adding 90 parts by mass of sodium dodecyl sulfate to 1600 parts by mass of ion-exchanged water, 420 parts by mass of “CI Pigment Yellow 74” was gradually added as a colorant. A colorant particle dispersion (yellow) was prepared by dispersing using a stirrer CLEARMIX (manufactured by M Technique Co., Ltd., “CLEARMIX” is a registered trademark of the company). The colorant particles in the dispersion had a volume-based median diameter of 110 nm.

<Colorant dispersion (magenta)>
In the production of the colorant dispersion (yellow), the colorant dispersion (magenta) was prepared in the same manner except that “CI Pigment Red 122” was used instead of “CI Pigment Yellow 74”. ) Was prepared. The colorant particles in the dispersion had a volume-based median diameter of 160 nm.

<Colorant dispersion (cyan)>
In the production of the colorant dispersion (yellow), the same colorant dispersion was used except that “CI Pigment Blue 15: 3” was used instead of “CI Pigment Yellow 74”. (Cyan) was prepared. The colorant particles in the dispersion had a volume-based median diameter of 150 nm.

<Colorant dispersion (black)>
In the production of the colorant dispersion (yellow), a colorant dispersion (black) was prepared in the same manner except that carbon black was used instead of “CI Pigment Yellow 74”. The colorant particles in the dispersion had a volume-based median diameter of 100 nm.

<Styrene acrylic resin dispersion 1 for core>
(First stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen gas introduction device was charged with 4 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water. The temperature was raised to 80 ° C. After the temperature increase, a solution in which 10 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was again adjusted to 80 ° C., and a mixture of the following monomers was added dropwise over 2 hours.

Styrene 570.0 parts by weight n-butyl acrylate 165.0 parts by weight Methacrylic acid 68.0 parts by weight After dropping the above mixture, polymerization is carried out by heating and stirring at 80 ° C. for 2 hours, and styrene acrylic resin for cores. A particle dispersion (1-a) was prepared.

(Second stage polymerization)
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling pipe and a nitrogen introducing device was charged with a solution prepared by dissolving 3 parts by mass of polyoxyethylene (2) sodium dodecyl ether sulfate in 1210 parts by mass of ion-exchanged water and heated to 80 ° C. did. After heating, 60 parts by mass of the amorphous vinyl resin particle dispersion (1-a) prepared by the first-stage polymerization in terms of solid content, the following monomers, chain transfer agent and release agent at 80 ° C. And the dissolved solution.

Styrene (St) 245.0 parts by mass 2-ethylhexyl acrylate (2EHA) 97.0 parts by mass Methacrylic acid (MAA) 30.0 parts by mass n-octyl-3-mercaptopropionate (chain transfer agent) 4.0 parts by mass Part Behenyl behenate (release agent, melting point 73 ° C.) 170.0 parts by mass Using a mechanical disperser CLEARMIX (registered trademark) (manufactured by M Technique Co., Ltd.) having a circulation path, the mixture is dispersed for 1 hour. A dispersion containing emulsified particles (oil droplets) was prepared. A solution of a polymerization initiator obtained by dissolving 5.2 parts by mass of potassium persulfate in 200 parts by mass of ion-exchanged water and 1000 parts by mass of ion-exchanged water were added to this dispersion, and this system was added at 84 ° C. for 1 hour. Polymerization was carried out by heating and stirring over time to prepare a styrene acrylic resin particle dispersion liquid (1-b) for core.

(3rd stage polymerization)
A solution prepared by dissolving 7 parts by mass of potassium persulfate in 130 parts by mass of ion-exchanged water was added to the styrene-acrylic resin particle dispersion for core (1-b) obtained by the second-stage polymerization. Furthermore, the liquid mixture of the following monomer and chain transfer agent was dripped over 1 hour on 82 degreeC temperature conditions.

Styrene (St) 350 parts by weight Methyl methacrylate (MMA) 50 parts by weight N-butyl acrylate (BA) 170 parts by weight Methacrylic acid (MAA) 35 parts by weight n-octyl-3-mercaptopropionate 8.0 parts by weight After completion of the dropwise addition, polymerization was carried out by heating and stirring for 2 hours, followed by cooling to 28 ° C. to prepare a styrene acrylic resin dispersion 1 for core. The styrene acrylic resin particles in the dispersion had a volume-based median diameter of 145 nm. Moreover, the weight average molecular weight of the obtained styrene acrylic resin was 35,000, and the glass transition temperature (Tg) was 37 degreeC.

(Yellow Toner 1)
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling pipe, 480 parts by mass (in terms of solid content) of the “core styrene acrylic resin particle dispersion 1” prepared above and “colorant dispersion (yellow)” were prepared. 42 parts by mass (in terms of solid content) and 500 parts by mass of ion-exchanged water were added, and the pH was adjusted to 10 by adding a 5 mol / L aqueous sodium hydroxide solution. Further, a solution prepared by dissolving 80 parts by mass of magnesium chloride hexahydrate in 80 parts by mass of ion-exchanged water was added at 30 ° C. over 10 minutes while stirring. After standing for 3 minutes, the temperature was raised to 81 ° C. (first-stage dispersion charging temperature) over 60 minutes. Thereafter, 60 parts by mass (converted to solid content) of “Crystalline polyester resin particle dispersion 1” mixed with 10 parts by mass (converted to solid content) of sodium dodecyl diphenyl ether disulfonate was added over 10 minutes to react. When the supernatant of the liquid became transparent, the stirring rate was adjusted so that the growth rate of the particle size was 0.02 μm / min, and the volume-based median measured by Coulter Multisizer 3 (Beckman Coulter, Inc.) When the diameter reached 5.8 μm, the stirring speed was adjusted to stop the particle size growth. Next, 60 parts by mass (in terms of solid content) of “Hybrid amorphous polyester resin particle dispersion 1 for shell” was added over 30 minutes, and when the supernatant of the reaction solution became transparent, 80 parts by mass of sodium chloride was added. An aqueous solution dissolved in 320 parts by mass of ion-exchanged water was added to stop the growth of the particle size. Next, the temperature was raised and the mixture was stirred at 80 ° C., and using a flow particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation), when the average circularity reached 0.970, the reaction solution was 10 ° C. The mixture was cooled to 25 ° C. at a cooling rate of / min to obtain a dispersion liquid of “yellow toner base particles 1”.

  The obtained dispersion was subjected to solid-liquid separation, and the dehydrated toner cake was redispersed in ion-exchanged water at 35 ° C., followed by washing by repeating solid-liquid separation three times. After washing, drying was performed at 40 ° C. for 24 hours to obtain “Yellow toner base particles 1” (volume-based median diameter 5.8 μm).

  To 100 parts by mass of the obtained toner base particles 1, 0.6 parts by mass of hydrophobic silica particles (number average primary particle size: 12 nm, degree of hydrophobicity: 68) and hydrophobic titanium oxide particles (number average primary particle size: 20 nm). Hydrophobic degree: 63) 1.0 part by mass and sol-gel silica (number average primary particle size: 110 nm, hydrophobizing degree: 63) are added by 1.0 part by mass, using a Henschel mixer (manufactured by Nihon Coke Kogyo Co., Ltd.). The rotating blade was mixed at 32 ° C. for 20 minutes at a peripheral speed of 35 mm / second. After mixing, coarse particles were removed using a sieve having an opening of 45 μm to obtain “Yellow Toner 1”.

(Yellow toner 2-3, 6)
In the production of yellow toner 1, yellow toners 2 to 3 and 6 were obtained in the same manner as yellow toner 1 except that the first-stage dispersion charging temperature was adjusted as shown in Table 1.

(Yellow Toner 4)
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling pipe, 480 parts by mass (in terms of solid content) of the “core styrene acrylic resin particle dispersion 1” prepared above and “colorant dispersion (yellow)” were prepared. 42 parts by mass (in terms of solid content) and 500 parts by mass of ion-exchanged water were added, and the pH was adjusted to 10 by adding a 5 mol / L aqueous sodium hydroxide solution. Further, a solution prepared by dissolving 80 parts by mass of magnesium chloride hexahydrate in 80 parts by mass of ion-exchanged water was added at 30 ° C. over 10 minutes while stirring. After standing for 3 minutes, the temperature was raised to 81 ° C. (first-stage dispersion charging temperature) over 60 minutes. Thereafter, the stirring speed was adjusted so that the growth rate of the particle diameter was 0.01 μm / min, and the volume-based median diameter measured by Coulter Multisizer 3 (manufactured by Beckman Coulter, Inc.) was 3.3 μm (first stage dispersion). At the time when the liquid input particle size) was reached, the stirring speed was adjusted to stop the particle size growth. Next, a solution obtained by mixing 10 parts by mass (in terms of solid content) of crystalline polyester resin particle dispersion 1 ”60 parts by mass (in terms of solid content) with 10 parts by mass (in terms of solid content) of sodium dodecyl diphenyl ether is added over 10 minutes, and the reaction solution When the supernatant became transparent, the stirring speed was adjusted again so that the growth rate of the particle size was 0.02 μm / min, and the volume-based measurement measured by Coulter Multisizer 3 (Beckman Coulter, Inc.) When the median diameter reached 5.8 μm, the stirring speed was adjusted to stop the particle size growth. Next, 60 parts by mass (in terms of solid content) of “Hybrid amorphous polyester resin particle dispersion 1 for shell” was added over 30 minutes, and when the supernatant of the reaction solution became transparent, 80 parts by mass of sodium chloride was added. An aqueous solution dissolved in 320 parts by mass of ion-exchanged water was added to stop the growth of the particle size. Next, the temperature was raised and the mixture was stirred at 80 ° C., and when the average circularity reached 0.970 using a flow type particle image measuring device “FPIA-3000” (manufactured by Sysmex Corporation), the reaction solution was cooled to 25 ° C. And a dispersion of “yellow toner base particles 4” was obtained.

  Subsequent steps were performed in the same manner as the yellow toner 1, and the yellow toner 4 was obtained.

(Yellow toner 5, 7-8)
In the production of the yellow toner 4, yellow toners 5 and 7 to 8 were obtained in the same manner except that the particle diameter of the first stage dispersion was adjusted as described in Table 1.

(Magenta toner 1-2)
In the production of yellow toner 1, “colorant dispersion (magenta)” is used instead of “colorant dispersion (yellow)”, and the number of parts by weight of the colorant dispersion is changed to 45 parts by weight. Magenta toners 1 and 2 were obtained in the same manner except that the dispersion charging temperature was adjusted as shown in Table 1.

(Cyan toner 1-5)
In the production of yellow toner 1, “colorant dispersion (cyan)” is used instead of “colorant dispersion (yellow)”, and the number of parts by weight of the colorant dispersion is changed to 30 parts by weight. Cyan toners 1 to 5 were obtained in the same manner except that the dispersion charging temperature was adjusted as shown in Table 1.

(Cyan toner 6)
<Preparation of styrene acrylic resin particle dispersion for shell>
A reaction vessel equipped with a stirrer, a temperature sensor, a cooling tube and a nitrogen gas introduction device was charged with 2 parts by mass of sodium dodecyl sulfate and 3000 parts by mass of ion-exchanged water. The temperature was raised to 80 ° C. After the temperature increase, a solution in which 10 parts by mass of potassium persulfate was dissolved in 200 parts by mass of ion-exchanged water was added, the liquid temperature was again adjusted to 80 ° C., and a mixture of the following monomers was added dropwise over 2 hours.

Styrene 460.0 parts by mass n-butyl acrylate 220.0 parts by mass Methacrylic acid 120.0 parts by mass n-octyl-3-mercaptopropionate (chain transfer agent) 3.3 parts by mass After the dropwise addition of the above mixture, 80 Polymerization was carried out by heating and stirring at ° C. for 2 hours to prepare a styrene acrylic resin particle dispersion for shell.

  Cyan toner 6 was obtained in the same manner as in the production of cyan toner 5, except that “styrene acrylic resin particle dispersion for shell” was used instead of “hybrid amorphous polyester resin particle dispersion for shell 1”.

<Black toner 1-2>
In the production of the yellow toner 1, the same procedure was performed except that “colorant dispersion (black)” was used instead of “colorant dispersion (yellow)” and the first-stage dispersion input temperature was adjusted as shown in Table 1. Thus, black toners 1 and 2 were obtained.

Examples 1-14, Comparative Examples 1-2
A combination of colored toners (yellow, magenta, cyan, black) described in Table 2 below was used.

<Production of Developers Y1-Y8, M1-M2, C1-C6, K1-K2>
100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) are put into a high-speed mixer equipped with stirring blades, and stirred and mixed at 120 ° C. for 30 minutes. Then, a resin coat layer was formed on the surface of the ferrite core by the action of mechanical impact force to obtain a carrier having a volume-based median diameter of 50 μm.

  Toners Y1 to Y8, M1 to M2, C1 to C6, and K1 to K2 are added to the carrier so that the toner concentration is 6% by mass, and the mixture is put into a micro type V type mixer (Tsutsui Rikenki Co., Ltd.). The developer Y1 to Y8, M1 to M2, C1 to C6, and K1 to K2 were prepared by mixing at a rotation speed of 45 rpm for 30 minutes.

<Evaluation of low-temperature fixability (under offset)>
Evaluation of low-temperature fixability was performed by changing the surface temperature of the fixing heat roller in the range of 130 to 170 ° C. in a commercially available multifunction machine “bizhub PRESS (registered trademark) C1070” (manufactured by Konica Minolta Business Technologies). A developer composed of the toner set described in “Table 2” is sequentially loaded so that the image forming apparatus can be used, and the image forming apparatus is used in an environment of normal temperature and normal humidity (temperature 20 ° C., relative humidity 50% RH). In a fixing experiment in which a solid image having a toner adhesion amount of 11.3 g / m ² is fixed to A4 size NPI 128 g / m ² (manufactured by Nippon Paper Industries Co., Ltd.), the set fixing temperature is increased from 130 ° C. in increments of 2 ° C. The fixing temperature at which under-offset does not occur was determined as the lower limit fixing temperature, and was used as an index for low-temperature fixability. Note that the solid image with the toner adhesion amount of 11.3 g / m ² reproduces the output of the high adhesion amount image. Under offset refers to an image defect that peels from a transfer material such as recording paper because the toner layer is not sufficiently melted by the heat applied when passing through the fixing device. The lower the fixing minimum temperature, the better the fixing property. Evaluation was made based on the following evaluation results.

A: 146 ° C. or lower ○: Over 146 ° C. and 152 ° C. or lower Δ: Over 152 ° C. and lower than 156 ° C. x: Over 156 ° C.

<Evaluation of glossiness>
For the evaluation of glossiness, the solid image used for the low-temperature fixability evaluation is measured using a glossiness meter “micro-gloss 75 °” (manufactured by BYK) at an incident angle of 75 ° with reference to the attached standard plate. I went there. The glossiness of the solid image is an average value of 5 points at the center and four corners of the measured image, and the image for evaluating the glossiness is a fixed solid image fixed at the fixing lower limit temperature + 20 ° C. in the low temperature fixability evaluation. It was. Evaluation was made based on the following evaluation results.

A: Glossiness is 52 or less B: Glossiness is over 52 and 60 or less Δ: Glossiness is over 60 and 70 or less X: Glossiness is over 70

<Evaluation of heat-resistant storage stability>
For each of the toners Y1 to Y8, M1 to M2, C1 to C6, and K1 to K2 prepared above, 0.5 g of the toner is placed in a 10 mL glass bottle with an inner diameter of 21 mm, the lid is closed, and the shaker “TAPDENSER KYT-2000 (Seisin Enterprise Co., Ltd.) and shaken 600 times at room temperature. After that, it was left for 2 hours in an environment of 55 ° C. and relative humidity of 35% RH with the lid open. Next, the toner is placed on a 48 mesh (aperture 350 μm) sieve, taking care not to break up the toner aggregates, and set in a “powder tester” (manufactured by Hosokawa Micron). Fixed. After adjusting the vibration intensity to a feed width of 1 mm and applying vibration for 10 seconds, the ratio (%) of the amount of toner remaining on the sieve was measured. The toner aggregation rate was calculated by the following mathematical formula (A), and the heat-resistant storage stability of each of Y1 to Y8, M1 to M2, C1 to C6, and K1 to K2 was evaluated according to the following evaluation criteria. The obtained toner aggregation rate results are shown in Table 2 below.

  Compared with Comparative Examples 1 and 2, the above-described Examples were excellent in both low gloss and low temperature fixability when outputting a high adhesion amount image.

  Further, in Example 10 having the toner (Y8) with W exceeding 1.00, the heat resistant storage property of the yellow toner was slightly lowered. Further, in Example 11 having the toner (C6) with W less than 0.02, the low-temperature fixability was slightly lowered as compared with Examples 8 and 11 in which the values of W (MAX) / W (MIN) were close. . Therefore, it can be seen that W of each toner is preferably 0.02 to 1.00.

  Further, the same effect can be obtained even if the color having the highest W value is magenta or black as in the twelfth and thirteenth embodiments.

Claims (8)

An image forming method for forming an image on a recording medium by superimposing toner images for developing electrostatic latent images of a plurality of colors,
Each of the multi-color electrostatic latent image developing toners forming the toner image includes an amorphous resin and a crystalline polyester resin, and is absorbed by a total reflection method using a Fourier transform infrared spectroscopic analyzer. when measured spectra has a maximum absorption peak at least absorption wave number in the range of range and 1190～1220Cm ^-1 of 690～710Cm ^-1,
The peak height of the absorption maximum peak in the range of absorption wave numbers 690～710Cm ^-1 to P1, the peak height of the absorption maximum peak in the range of the absorption wave numbers 1190～1220Cm ^-1 and P2, in the toner When the ratio of P2 to P1 is W = P2 / P1, the ratio of W (MAX) to minimum value W (MIN) W (MAX) / W (MIN) is 1.20 to 20.00. , Image forming method.   The image forming method according to claim 1, wherein W of each toner is 0.02 to 1.00. The crystalline polyester resin includes a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded,
The image according to claim 1 or 2, wherein the amorphous resin includes a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. Forming method.   The image forming method according to claim 3, wherein the vinyl polymerization segment is a styrene acrylic polymerization segment. A toner set including toner for developing electrostatic latent images of a plurality of colors,
Each of the toners includes an amorphous resin and a crystalline polyester resin, and has an absorption wave number of at least 690 to 710 cm ⁻ when an absorption spectrum is measured by a total reflection method using a Fourier transform infrared spectroscopy analyzer. It has an absorption maximum peak in the range of ¹ range and 1190~1220cm ^-1,
The peak height of the absorption maximum peak in the range of absorption wave numbers 690～710Cm ^-1 to P1, the peak height of the absorption maximum peak in the range of the absorption wave numbers 1190～1220Cm ^-1 and P2, in the toner When the ratio of P2 to P1 is W = P2 / P1, the ratio of W (MAX) to minimum value W (MIN) W (MAX) / W (MIN) is 1.20 to 20.00. , Toner set.   The toner set according to claim 5, wherein W of each toner is 0.02 to 1.00. The crystalline polyester resin includes a hybrid crystalline polyester resin in which a crystalline polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded,
The toner according to claim 5 or 6, wherein the amorphous resin includes a hybrid amorphous polyester resin in which an amorphous polyester polymer segment and a vinyl polymer segment having a structural unit derived from styrene are chemically bonded. set.   The toner set according to claim 7, wherein the vinyl polymer segment is a styrene acrylic polymer segment.