JP2005352116A - Toner for electrophotography, its production method, developer for electrophotography, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide toner for electrophotography in which heat resistance and low temperature fixing properties are compatible, and which has high mechanical strength as well, and its production method, and to provide a developer for electrophotography, and an image forming apparatus. <P>SOLUTION: The toner for electrophotography contains at least a binding resin including a thermoplastic resin, and a coloring agent, wherein the thermoplastic resin is obtained by a process (1) where a melting mixing temperature: T<SB>0</SB>[°C] and a melting mixing time:t<SB>0</SB>[min] are obtained so that the luminous reflectance Y becomes 1.5 [%] when a mixed polyester based resin obtained by melting and mixing a crystalline polyester resin and an amorphous polyester resin is formed into a film with a thickness of 20 [μm], and a process (2) where the crystalline polyester resin and the amorphous polyester resin are melted and mixed under the conditions of the melting mixing temperature: T<SB>0</SB>to T<SB>0</SB>+20 [°C], and the melting mixing time: t<SB>0</SB>to t<SB>0</SB>+10 [min]. The production method of the toner, the developer for electrophotography consisting of the toner and a carrier, and the image forming apparatus using the developer are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrophotographic toner that can be used in an electrophotographic apparatus using an electrophotographic process such as a copying machine, a printer, and a facsimile, a manufacturing method thereof, an electrophotographic developer, and an image forming apparatus.

Conventionally, in a color image forming apparatus for forming a color image by an electrophotographic method or an electrostatic recording method, a color image is formed on the surface of a recording medium. For example, when a color copy is made, the following image formation is performed. Process operations are performed.
Illuminate a color document, read the reflected light image by color separation with a color scanner, perform predetermined image processing and color correction with an image processing device, and based on the obtained multiple-color image signals, for example, a semiconductor laser And a laser beam modulated according to the image signal is emitted from the semiconductor laser. By irradiating the surface of an organic photoreceptor using Se or amorphous silicon or an organic photoreceptor using a phthalocyanine pigment or a bisazo pigment as a charge generation layer, a plurality of electrostatic latent images are formed. Form. A plurality of electrostatic latent images formed on the surface of the inorganic or organic photoreceptor are sequentially developed with four color toners such as yellow (Y), magenta (M), cyan (C), and black (K) each time. To do. Then, the developed toner image is transferred from the inorganic or organic photosensitive member to the surface of the recording medium such as paper, and is heat-fixed by a fixing device including a heat fixing roll to form a color image on the surface of the recording medium. .
The electrophotographic system is exclusively used for copying, office printers and facsimiles, but has recently begun to be used for high value-added printing applications such as photographic image printing and light printing.

By the way, the preference for the glossiness of a color image varies depending on the type and purpose of use of the image, and there are many kinds. High-gloss images tend to be preferred. In light printing applications, high gloss coated paper is often used, and high gloss equivalent to that of coated paper tends to be required.
It is known that the viscosity of a toner at the time of heat fixing changes and the glossiness of a color image changes depending on the type of binder resin used for the toner, the method of heat fixing, and the like.
In a color image forming apparatus, a technique for obtaining a highly glossy image has already been proposed. In these documents, a color copying machine is used to select a toner material, fixing conditions, etc. It describes that an image can be obtained (for example, see Patent Documents 1 to 3).

  Further, in Patent Document 4, a toner image is formed on a recording medium provided with a toner receiving layer, or a recording medium on which a toner image and a toner image are formed is heated and melted using a belt-type fixing device. An apparatus that forms a high-gloss image such as a silver salt photograph by cooling and peeling has been proposed (see, for example, Patent Document 4).

  However, in the case of the techniques described in Patent Documents 1 to 3, the unevenness of the toner remains on the surface of the image and does not become smooth like a silver salt photograph or printing, so that a smooth texture cannot be obtained. Also have. In order to make the toner flow as smooth as possible, the fixing process must be performed at a higher temperature and a higher pressure for a longer time in order to make the toner flow more.

Further, when using the apparatus of the above-mentioned Patent Document 4, in order to embed toner in the toner receiving layer or to fix a bulky toner image in addition to the toner image, the fixing process is also made high temperature and high pressure for a long time. I do not get. When the speed of the recording medium passing through the fixing device is high, a step is conspicuous at the boundary between the high density part and the low density part, and the low density small spot in the high density part is indented like a hole. It has the problem that it ends up. This is because the toner is embedded in the toner receiving layer, or the flow of the binder resin in the toner is not sufficient to fill the level difference of the toner image.
In addition to the reasons described above, thick coated paper is often used as a recording medium for photographic image printing and light printing, and it can be said that the amount of heat taken away by the recording medium in the fixing process is large.
Since the energy required for fixing is large, as long as the temperature and pressure conditions of the fixing device are used in a practical range, the technique described in the above document achieves both a high printing speed and a uniform image with high gloss. There is a problem that you can not.
Considering the reduction of energy consumption in image production to solve this problem, low-temperature fixability is an essential issue, but in order to satisfy this low-temperature fixability, the molecular weight of the resin is reduced and the glass transition point is lowered. Is an effective solution.

However, the electrophotographic toner used in the above technique has a durability problem that a fixed toner layer is deformed or offset in a high temperature and high humidity environment or by long-term storage.
Blocking (when stored in a car or warehouse in summer or left in a high-temperature environment such as transporting at the bottom of a ship, with the image surface and back, image surfaces overlapping, and the image surface and album material, etc.) There is a concern that a problem may occur that the surface cannot be peeled off or the surface is damaged even if it is peeled off. In this case, in order to improve durability at high temperatures, that is, heat resistance, it is effective to increase the glass transition point and increase the molecular weight. Furthermore, an improvement in durability when the image is bent, that is, improvement in mechanical strength is also an important issue. Increasing molecular weight is an effective solution to increase mechanical strength.

  Thus, the improvement direction of mechanical strength and heat resistance is contrary to the improvement direction of low-temperature fixability. In particular, when a high gloss image is produced for applications such as photographic image printing and light printing, it is necessary to make the fixing temperature higher, making it more difficult to satisfy all three requirements.

Regarding the mechanical strength, conventional toners using an amorphous resin have a problem that the mechanical strength against bending is low and cracking is likely to occur. In recent years, there has been a demand for a binder resin for toner that has excellent low-temperature fixability and good storage stability. See 5 and 6.).
These technologies seem to be effective technologies that achieve both low-temperature fixability and heat resistance durability against offset and blocking, but in the long run, embrittlement and gloss fluctuations occur due to slow crystallization. There is a problem. In the case of a toner using a crystalline resin, even if it is supple after fixing, if time passes and crystallization progresses, peeling easily occurs at the crystal interface, and depending on the material, it cracks more than an amorphous resin. Is likely to occur.

  Assuming high-value-added printing applications such as electrophotographic photographic image printing and light printing, cracks generated on a uniform glossy surface are very conspicuous, and the print value is greatly impaired. In particular, a color image having a high toner volume formed on thick paper has a large stress when a bending mechanical force is applied, and therefore, a crack is generated by a slight external force.

If photographic image printing and light printing by electrophotography require the same quality as existing silver salt photography and offset printing, improvement of the cracks in the toner image that forms the image is one of the most serious issues. I can say that.
JP-A-5-142963 JP-A-3-2765 JP-A 63-259575 JP-A-5-158364 JP 2001-222138 A JP 11-249339 A

  The present invention has been made to solve the above technical problems, and is an electrophotographic toner that has both heat resistance and low-temperature fixability, and also has high mechanical strength, a method for producing the same, and electrophotographic development. An agent and an image forming method are provided.

The present inventors have formed an image using an electrophotographic toner made of a binder resin having specific properties, so that the energy consumption is small and the temperature and humidity can be reduced even when a high-speed fixing device is used. It has been found that image quality deterioration such as offset and cracking due to influence can be suppressed, and the present invention has been completed.
That is, the present invention

<1> A toner for electrophotography containing at least a binder resin containing a thermoplastic resin and a colorant, wherein the thermoplastic resin is a mixed polyester system in which a crystalline polyester resin and an amorphous polyester resin are melt-mixed. An electrophotographic toner comprising a resin, wherein the crystalline polyester resin and the amorphous polyester resin are melt-mixed by the following steps (1) and (2).
(1) Luminous reflectance Y when a mixed polyester resin obtained by melt-mixing the crystalline polyester resin and the amorphous polyester resin into a film having a thickness of 20 [μm] is 1.5 in advance. The melt mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min], which are [%], are determined.
(2) Next, the crystalline polyester resin and the amorphous polyester resin are melted under the conditions of melt mixing temperature: T _{0 to} T ₀ +20 [° C.] and melt mixing time: t _{0 to} t ₀ +10 [min]. Mix.

<2> The melt mixing ratio of the crystalline polyester resin and the amorphous polyester resin is a mass ratio in a range of 35:65 to 65:35. For electrophotography according to <1> Toner.
<3> The crystalline polyester resin and the amorphous polyester resin are melt-mixed under conditions of a melt mixing temperature: T ₀ +5 to T ₀ +10 [° C.] and a melt mixing time: t _{0 to} t ₀ +5 [min]. <1> or <2>, wherein the toner is for electrophotography.

<4> At least one component of the alcohol-derived component and the acid-derived component in the crystalline polyester resin is the same as one component of the alcohol-derived component and the acid-derived component in the amorphous polyester resin. The toner for electrophotography according to any one of <1> to <3>.
<5> The electrophotographic toner according to any one of <1> to <4>, wherein the crystalline polyester resin and the amorphous polyester resin each contain three or more monomers. .

<6> The toner for electrophotography according to <5>, wherein the crystalline polyester resin and the amorphous polyester resin all have the same alcohol-derived component and acid-derived component. .
<7> The alcohol-derived constituent component of the crystalline polyester resin contains 85 to 98 mol% of a linear aliphatic component having 6 to 12 carbon atoms with respect to the total alcohol-derived constituent component, The acid-derived constituent component is an aromatic-derived constituent component derived from 90 mol% or more of terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, or 2,6-naphthalenedicarboxylic acid with respect to the total acid-derived constituent component. The toner for electrophotography according to any one of <4> to <6>, wherein the toner is for electrophotography.

<8> The alcohol-derived constituent component contained in the amorphous polyester resin is the same linear aliphatic as the straight chain aliphatic group having 6 to 12 carbon atoms contained in the alcohol-derived constituent component of the crystalline polyester resin. The acid-derived component contained in the amorphous polyester resin is contained in an amount of 10-30 mol% based on the component derived from terephthalic acid, dimethyl terephthalate, isophthalic acid, isophthalic acid contained in the acid-derived component of the crystalline polyester resin. The toner for electrophotography according to <7>, comprising 90 mol% or more of the same aromatic as the aromatic derived from dimethyl acid or 2,6-naphthalenedicarboxylic acid with respect to the total acid-derived constituent component It is.

<9> The alcohol-derived constituent component of the crystalline polyester resin is 85 to 98 mol% of a linear aliphatic component having 6 to 12 carbon atoms and 2 to 15 mol% of an aroma with respect to all alcohol-derived constituent components. The alcohol-derived constituent component of the amorphous polyester resin is 10 to 30 mol% of the linear aliphatic component having 6 to 12 carbon atoms with respect to the total alcohol-derived constituent component. The same linear aliphatic component and a component derived from 70 to 90 mol% of an aromatic diol, and the acid-derived constituent components of the crystalline polyester resin and the amorphous polyester resin each include the same aromatic component. The toner for electrophotography according to any one of <1> to <8>, wherein the toner is for electrophotography.

<10> The crystalline polyester resin has a weight average molecular weight of 16000 to 40000, and the amorphous polyester resin has a weight average molecular weight of 8000 to 26000. <1> to <9> One of them is an electrophotographic toner.
<11> The crystalline polyester resin has a number average molecular weight Mn (c) and a resin acid value AV (c) of (1.12 × 10 ⁴ ) / Mn (c) <AV (c) <(2.25 × 10 ⁵ ) / Mn (c), and the amorphous polyester resin has a number average molecular weight Mn (a) and a resin acid value AV (a) of (5.61 × 10 ⁴ ) / Mn (a). <10> The electrophotographic toner according to <10>, wherein the relationship <AV (a) <(2.25 × 10 ⁵ ) / Mn (a) is satisfied.

<12> The crystalline polyester resin has a weight average molecular weight of 16000 to 28000, a number average molecular weight Mn (c) and a resin acid value AV (c) of (8.96 × 10 ⁴ ) / Mn (c) < AV (c) <(1.34 × 10 ⁵ ) / Mn (c) is satisfied, and the amorphous polyester resin has a weight average molecular weight of 8000 to 20000, and the number average molecular weight Mn (a) and the resin Acid value AV (a) satisfies the relationship of (8.96 × 10 ⁴ ) / Mn (a) <AV (a) <(1.34 × 10 ⁵ ) / Mn (a) <10 > Or <11>.

<13> The crystalline polyester resin contains bisphenol S or a bisphenol S alkylene oxide adduct in a range of 2 to 15 mol% with respect to all alcohol-derived components <1> to <12> The toner for electrophotography according to any one of the above.
<14> The amorphous polyester resin contains bisphenol S or a bisphenol S alkylene oxide adduct in a range of 2 to 90 mol% with respect to all alcohol-derived components <1> to <13 The toner for electrophotography according to any one of the above.

<15> A toner for electrophotography containing at least a binder resin containing a thermoplastic resin and a colorant, wherein the thermoplastic resin is a mixed polyester system obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin. An electrophotographic toner comprising a resin and a luminous reflectance Y [%] of 1.5% or less when the mixed polyester resin is formed into a film having a thickness of 20 [μm].
<16> An electrophotographic developer comprising a carrier and a toner,
An electrophotographic developer, wherein the toner is the electrophotographic toner according to any one of <1> to <15>.

<17> A latent image forming apparatus for forming an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member, and the electrostatic latent image formed on the surface of the latent image holding member is A developing device for developing and forming a toner image, a transfer device for transferring the toner image formed on the surface of the latent image holding member to the surface of the transfer target, and the toner image transferred to the surface of the transfer target are thermally fixed. An image forming apparatus including the fixing device, wherein the developer includes the electrophotographic toner according to any one of <1> to <15>.

<18> A toner for electrophotography containing at least a binder resin containing a thermoplastic resin and a colorant, wherein the thermoplastic resin includes a mixed polyester resin obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin. And a melt mixing step of preparing a mixed polyester resin by melt-mixing the crystalline polyester resin and the amorphous polyester resin by the following steps (1) and (2): A feature of the present invention is a method for producing an electrophotographic toner.
(1) Luminous reflectance Y [%] when a mixed polyester resin obtained by melt-mixing the crystalline polyester resin and the amorphous polyester resin is formed into a film having a thickness of 20 [μm] in advance. The melt mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] are determined to be 1.5%.
(2) Next, the crystalline polyester resin and the amorphous polyester resin are melted under the conditions of melt mixing temperature: T _{0 to} T ₀ +20 [° C.] and melt mixing time: t _{0 to} t ₀ +10 [min]. Mix.

  The present invention achieves both heat resistance and low-temperature fixability by a fixing device with low energy consumption, and also has high mechanical strength against cracks and the like, and a method for producing the same, an electrophotographic developer, and image formation A method is provided.

The electrophotographic toner of the present invention will be described in detail below.
The electrophotographic toner of the present invention is for forming a toner image on the surface of a transfer medium by electrophotography, and then transferring and fixing the toner image on or around the toner image, and includes a binder containing a thermoplastic resin. The thermoplastic resin contains at least a resin and a colorant, and the thermoplastic resin includes a mixed polyester resin in which a crystalline polyester resin and an amorphous polyester resin are melt-mixed, and the crystalline polyester resin and the amorphous polyester resin are melted. The mixing is performed by the following steps (1) and (2).
(1) Luminous reflectance Y [%] when a mixed polyester resin obtained by melt-mixing the crystalline polyester resin and the amorphous polyester resin is formed into a film having a thickness of 20 [μm] in advance. The melt mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] are determined to be 1.5%.
(2) Next, the crystalline polyester resin and the amorphous polyester resin are melted under the conditions of melt mixing temperature: T _{0 to} T ₀ +20 [° C.] and melt mixing time: t _{0 to} t ₀ +10 [min]. Mix.

In the electrophotographic toner of the present invention, the crystalline polyester resin and / or the amorphous polyester resin is melt-mixed by the steps (1) and (2), so that the crystalline polyester resin and / or Amorphous polyester resin can be dispersed without causing thermal turbidity, embrittlement, etc. after fixing due to thermal decomposition, plasticization, or slow growth of crystalline polyester crystals. As described later, a mixed polyester resin having a luminous reflectance Y [%] of 1.5% or less, which is a preferred embodiment of the mixed polyester resin in the present invention, is obtained.
The melt mixing of the crystalline polyester resin and the amorphous polyester resin is not limited as long as it is performed by the steps (1) and (2) in the previous period, and examples thereof include a method of mixing using an extrusion kneader.

In the step (2), when the melt mixing temperature is less than T ₀ [° C.], the dispersion becomes incomplete, both heat resistance and low-temperature fixability can be achieved, and an electrophotographic toner having high mechanical strength is obtained. In other words, the effect of the present invention is not obtained, and white turbidity and embrittlement after fixing are caused by the slow growth of crystalline polyester crystals. On the other hand, when the melt mixing temperature exceeds T ₀ +20 [° C.], the crystalline polyester resin and / or the amorphous polyester resin undergo thermal decomposition, plasticization, and the like.
The melt mixing temperature in the step (2) is preferably T ₀ +5 to T ₀ +10 [° C.].

In the step (2), when the melt mixing time is less than t ₀ [min], dispersion is incomplete, heat resistance and low-temperature fixability can both be achieved, and an electrophotographic toner having high mechanical strength can be obtained. In other words, the effect of the present invention is not obtained, and white turbidity and embrittlement after fixing are caused by the slow growth of crystalline polyester crystals. On the other hand, when the melt mixing time exceeds t ₀ +10 [minutes], the crystalline polyester resin and / or the amorphous polyester resin undergo thermal decomposition, plasticization, and the like.
The melt mixing time in the step (2) is preferably t _{0 to} t ₀ +5 [min].

The mixed polyester resin in the present invention preferably has a luminous reflectance Y [%] of 1.5% or less, a melt mixing temperature: T _{0 to} T ₀ +20 [° C.], and a melt mixing time: t _0. It is preferable to make the luminous reflectance Y [%] lower (ideally 0%) by melt-mixing under a condition of ˜t ₀ +10 [min]. When the luminous reflectance Y [%] exceeds 1.5%, the dispersion of the crystalline resin is insufficient, and white turbidity or embrittlement occurs after a while after fixing. This white turbidity / embrittlement does not appear after fixing, but occurs within a few minutes to a few days and impairs the sharpness and glossiness of the image.
The mixed polyester resin according to the present invention has a luminous reflectance Y [%] by melting and mixing the crystalline polyester resin and the amorphous polyester resin in the steps (1) and (2). It can be made 1.5% or less.

Here, the luminous reflectance Y will be described.
The luminous reflectance Y in the present invention is a polyester resin (in the present invention, a mixed polyester resin obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin) having a thickness of 20 [μm]. The luminous reflectance of the film when it is made into a film. More specifically, it is a value measured as follows.
First, a polyester resin is molded into a film (thickness 20 [μm]) (hereinafter, the obtained film may be referred to as “resin film”). And in order to remove the scattering component of the surface and back surface, the said resin film is pinched | interposed with the transparent cover glass for microscope observation, and a refractive index matching liquid (tetradecane) is satisfy | filled between glass and a resin film. The sample is subjected to reflection measurement on a light and a lap with a colorimeter that satisfies the 0/45 degree geometric colorimetric condition (for example, X-rire968, manufactured by X-rire). The Y value in the CIE XYZ color system measured in this way is the luminous reflectance Y. When the film to be measured is transparent and the cover glass is also transparent, Y is almost zero. That is, the value of Y corresponds to the intensity of the scattering component inside the resin film.

On the other hand, when measuring a general crystalline polyester resin that has become turbid due to growth of spherulites, or a polyester resin that has undergone crystal dispersion by melt mixing or crystal dispersion by copolymerization component, but is insufficiently dispersed The scattering intensity due to resin crystal dispersion is strong, and the value of luminous reflectance Y increases.
Further, as the crystal dispersion of the polyester resin becomes finer due to melt mixing or a copolymer component such as bisphenol S, the value of the luminous reflectance Y decreases. Therefore, the luminous reflectance Y is an index of the crystal dispersion size.

The thickness of the resin film used for the measurement is of course preferably 20 [μm], but when the scattering of the resin film used for the measurement is 2% or less, the value of the luminous reflectance Y is resin. Since it is proportional to the thickness of the film, even if the thickness of the film is not exactly 20 [μm], the measured value of the luminous reflectance Y is multiplied by 20 [μm], and the thickness of the resin film used for the measurement [μm] The luminous reflectance Y may be calculated by dividing by.
The method for producing the resin film used for the measurement is not particularly limited as long as the purpose of forming a film having a uniform and uniform thickness is not impaired. For example, a base material with a smooth top surface and good releasability is placed on a top plate such as a hot plate, and the polyester resin to be measured is melted on this base material and applied with Erichsen or a bar coater. The resin film used for the measurement can be obtained by the method of peeling the film from the substrate.

  In addition, a film prepared on a suitable base material is layered on a transparent film such as a PET film, heated and pressurized, peeled off the base material, and transferred to another transparent film as a sample. Y may be measured. In this case, by subtracting the reflectance Y0 of the other transparent film itself from the measured luminous reflectance Yt of the sample transferred to the other transparent film, the luminous reflectance Y of the resin film to be measured is calculated. can do.

  The mixing ratio (mass ratio) of the crystalline polyester resin and the amorphous polyester resin in the mixed polyester resin described above is preferably 35:65 to 65:35, and 40:60 to 60:40. It is more preferable, and it is still more preferable that it is 45: 55-55: 45. When the mixing ratio is 35:65 to 65:35, it is preferable in terms of heat resistance, mechanical strength, and melt mixing property.

The binder resin in the present invention may further contain a resin other than the mixed polyester resin described above as a thermoplastic resin, but the content of the mixed polyester resin in all the binder resin components is 70% by mass. Preferably, it is 80% by mass or more, more preferably 90% by mass or more, and particularly preferably all are mixed polyester resins.
The crystalline polyester resin or the amorphous polyester resin in the polyester resin may be copolymerized with other components (third component) for the purpose of adjusting the melting point with respect to the main chain. If the ratio of the copolymerized component is 50% by mass or less, this copolymer is also a crystalline polyester resin or an amorphous polyester resin in the present invention. The ratio of the other component in the copolymerized polymer is preferably 12.5% by mass or less, and more preferably 2% by mass or less.
Moreover, the crystalline polyester resin and the amorphous polyester resin in the thermoplastic resin may be one kind, or a mixture of two or more kinds may be used.

  The thermoplastic resin other than the mixed polyester resin is not particularly limited, and a conventionally known resin can be used. Specific examples include polyester resins, styrene / acrylic copolymers, styrene / butadiene copolymers, and the like.

<Thermoplastic resin>
(Crystalline polyester resin)
The crystalline polyester resin preferably has a melting point of 80 to 130 ° C, more preferably 80 to 100 ° C, and still more preferably 85 to 95 ° C.
The weight average molecular weight is preferably 15000 to 50000, and more preferably 16000 to 40000 or less from the viewpoint of low temperature fixability and mechanical strength.
In the present invention, the melting point of the polyester resin is measured by using a differential scanning calorimeter (DSC), and the top of the endothermic peak when measured at a heating rate of 10 ° C./min from room temperature to 150 ° C. It is obtained from the value of.
Here, the “crystallinity” of the “crystalline polyester resin” in the present invention means that, in differential scanning calorimetry (DSC), it has a clear endothermic peak, not a stepwise endothermic amount change. In the case of a polymer obtained by copolymerizing other components with the crystalline polyester main chain, if the other components are small and have a clear endothermic peak of the polyester main chain in differential scanning calorimetry (DSC), The copolymer is also a crystalline polyester resin.

In order to increase the flexibility of the crystalline polyester resin, the alcohol-derived constituent component of the crystalline polyester resin is preferably a linear aliphatic component having 6 to 12 carbon atoms.
As alcohol for becoming the said alcohol-derived structural component, aliphatic diol is preferable.
Specific examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,7-heptanediol. 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol 1,18-octadecanediol, 1,20-eicosanediol and the like, but are not limited thereto. In addition, the aliphatic diol is preferably a linear aliphatic diol having 6 to 12 carbon atoms and more preferably a nonane diol having 9 carbon atoms from the viewpoint of fixing property and heat resistance. preferable.
Furthermore, the said C6-C12 linear aliphatic component, especially aliphatic diol are contained in 85-98 mol% with respect to all the alcohol origin structural components from a viewpoint of melt mixing property and low temperature fixability. It is preferable.

Examples of the acid for forming the acid-derived constituent component include various aromatic and aliphatic dicarboxylic acids, and aromatic dicarboxylic acids are preferred from the viewpoints of melt-mixability, mechanical strength, and heat resistance. .
Examples of the aromatic dicarboxylic acid include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-naphthalenedicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like. Among these, terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, and 2,6-naphthalenedicarboxylic acid are preferable in terms of low-temperature fixability and mechanical strength, and from the viewpoint of maintaining good melt mixing properties, all acids The aromatic component is preferably in the range of 90 mol% or more with respect to the derived constituent component.
Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelic acid, sebacic acid, 1,9-nonanedicarboxylic acid, and 1,10-decanedicarboxylic acid. 1,11-undecanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, Or lower alkyl esters and acid anhydrides thereof are not limited thereto.

  The crystalline polyester resin acid-derived constituent component is preferably copolymerized with a third component at a ratio of 2 to 12.5 mol% in order to improve melt mixing properties. When the ratio of the third component is less than 2 mol%, the melt mixing property is lowered, the mixing temperature may be increased, or the mixing time may have to be lengthened, the productivity is deteriorated, and the heat resistance is reduced. May be exacerbated. On the other hand, when the ratio of the third component exceeds 12.5 mol%, the melt mixing property is increased, but the crystallinity is lowered and the heat resistance is deteriorated. When stored in a high temperature warehouse or in a vehicle, problems such as blocking and offset may occur.

As the third component, bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, hydrogenated bisphenol A, bisphenol S, bisphenol S ethylene oxide adduct, bisphenol S propylene are used from the viewpoint of improving melt mixing properties. It is preferable to use a diol component such as a bisphenol S alkylene oxide adduct such as an oxide adduct. Further, from the viewpoint of toner manufacturability, heat resistance, and transparency, it is particularly preferable to use bisphenol S, or bisphenol S alkylene oxide adducts such as bisphenol S ethylene oxide adduct and bisphenol S propylene oxide adduct.
From the viewpoint of heat resistance, the alcohol-derived third component is preferably in the range of 2 to 15 mol%, more preferably in the range of 3 to 8 mol%, with respect to all alcohol-derived components.

  As the third component, an acid-derived constituent component may be added from the viewpoint of melt mixing properties. By adding two or more acid-derived components, the crystallinity is lowered and the melt mixing property is increased. In order to eliminate the deterioration of heat resistance due to the decrease in crystallinity, the ratio of the third component to the total acid-derived component is preferably 10% or less.

There is no restriction | limiting in particular as a manufacturing method of the said crystalline polyester resin, It can manufacture with the general polyester polymerization method which makes an acid component and an alcohol component react. That is, an oligomer can be obtained by esterifying or transesterifying a dibasic acid and a dihydric alcohol, and then synthesized by performing a polycondensation reaction under vacuum. Further, it can also be obtained by a polyester depolymerization method as described in JP-B-53-37920, for example. In addition, as a dibasic acid, a transesterification reaction is performed using at least one alkyl ester of a dicarboxylic acid such as dimethyl terephthalate, and then a polycondensation reaction is performed. A condensation reaction may be performed.
For example, the dibasic acid and the dihydric alcohol are reacted at 180 to 200 ° C. under atmospheric pressure for 2 to 5 hours, and the distillation of water or alcohol is terminated to complete the transesterification reaction. Next, the pressure in the reaction system is set to a high vacuum of 1 mmHg or less, and the temperature is raised to 200 to 230 ° C. and heated at this temperature for 1 to 3 hours to obtain a crystalline polyester resin.

The amorphous polyester resin preferably has a glass transition point of 50 to 80 ° C, and more preferably 55 to 65 ° C. The weight average molecular weight is preferably 8000 to 30000, and from the viewpoint of low temperature fixability and mechanical strength, the weight average molecular weight is more preferably 8000 to 26000, and further preferably 8000 to 16000.
As the amorphous polyester resin, a third component may be further copolymerized from the viewpoint of low-temperature fixability and mixing properties.
Here, “amorphous” of “amorphous polyester resin” in the present invention is a stepwise endothermic change in differential scanning calorimetry (DSC) and does not have a clear endothermic peak. Point to.

  The amorphous polyester resin preferably has an alcohol-derived constituent component or acid-derived constituent component common to the crystalline polyester resin in order to improve melt mixing properties. In particular, the alcohol-derived constituent component of the crystalline polyester resin includes a linear aliphatic component having 6 to 12 carbon atoms, and the acid-derived constituent component is derived from the terephthalic acid, isophthalic acid, or naphthalenedicarboxylic acid as the main component. When the component is included, the same linear aliphatic alcohol-derived constituent component is included in the range of 10 to 30 mol% with respect to the total diol, and the same acid-derived constituent aromatic component is included with respect to the total acid-derived constituent component. By containing 90 mol% or more, in addition to satisfying the low-temperature fixability, the melt-mixability is enhanced, and the mixture can be melt-mixed at a low temperature and good in heat resistance can be obtained.

  Furthermore, when an aromatic component that is an alcohol-derived constituent component is included as the third component of the crystalline polyester resin, the same aromatic component is used as the main component of the alcohol-derived constituent component of the amorphous polyester resin. It is particularly preferable from the viewpoint of melt mixing property, heat resistance, and low-temperature fixability that the aromatic component is contained in the range of 70 to 90 mol% with respect to the component.

The method for producing the amorphous polyester resin is not particularly limited as in the method for producing the crystalline polyester resin, and can be produced by the general polyester polymerization method as described above.
As the acid-derived constituent component, various dicarboxylic acids mentioned for the crystalline polyester can be used similarly. As the alcohol-derived constituent component, various diols can be used, but in addition to the aliphatic diols mentioned for the crystalline polyester, bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct and hydrogenation Bisphenol A, bisphenol S, bisphenol S ethylene oxide adduct, bisphenol S propylene oxide adduct, and the like can be used. Further, from the viewpoint of toner manufacturability, heat resistance, and transparency, it is particularly preferable to use bisphenol S and bisphenol S alkylene oxide adducts such as bisphenol S ethylene oxide adduct and bisphenol S propylene oxide adduct. In this case, bisphenol S, and bisphenol S alkylene oxide adducts such as bisphenol S ethylene oxide adduct and bisphenol S propylene oxide adduct are contained in the range of 2 to 90 mol% with respect to the alcohol-derived constituent component. Preferably it is.
In the case of an amorphous polyester resin, both the acid-derived constituent component and the alcohol-derived constituent component may contain a plurality of components. In particular, bisphenol S has an effect of improving heat resistance when amorphous. From the viewpoint of low-temperature fixability, it is preferable to use another third component, such as a bisphenol A derivative, depending on the composition of the amorphous resin.

It is preferable that at least one component of the alcohol-derived component and the acid-derived component in the crystalline polyester resin is the same as one of the alcohol-derived component and the acid-derived component in the amorphous polyester resin. Further, the alcohol-derived constituent component and the acid-derived constituent component in the crystalline polyester resin each preferably contain three or more monomers, and in this case, the respective alcohol origins in the crystalline polyester resin and the amorphous polyester resin It is more preferable that all of the constituent components and the acid-derived constituent components match.

  Here, as a preferred embodiment of the alcohol-derived constituent component and acid-derived constituent component of the crystalline polyester resin, from the viewpoint of low-temperature fixability, heat resistance, melt mixing property, and mechanical strength, the alcohol-derived constituent of the crystalline polyester resin. The component includes 85 to 98 mol% of a linear aliphatic component having 6 to 12 carbon atoms based on the total alcohol-derived constituent component, and the acid-derived constituent component of the crystalline polyester resin is a total acid-derived constituent component. On the other hand, the aspect containing the aromatic origin structural component derived from 90 mol% or more of terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, or 2,6-naphthalenedicarboxylic acid is mentioned.

  In the above aspect, the alcohol-derived constituent component and the acid-derived constituent component in the amorphous polyester resin satisfy the low-temperature fixability, heat resistance, melt mixing property, etc. 10-30 mol% of the same linear aliphatic as the C6-C12 linear aliphatic which is the main component with respect to the total alcohol-derived constituent component, and the acid-derived constituent component in the amorphous polyester resin, The same aromatics derived from terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, or 2,6-naphthalenedicarboxylic acid, which are the main components of the acid-derived constituent components of crystalline polyester resins, are derived from total acid It is more preferable to contain 90 mol% or more with respect to a structural component.

  Furthermore, in the said aspect, from the viewpoint of melt mixing property, heat resistance, and low-temperature fixability, the alcohol-derived constituent component of the crystalline polyester resin has a carbon number of 85 to 98 mol% with respect to the total alcohol-derived constituent component. To 12 linear aliphatic components and 2 to 15 mol% of an aromatic diol-derived component, and the alcohol-derived component of the amorphous polyester resin is 10 to 10% of the total alcohol-derived component. 30% by mol of the same linear aliphatic component as the linear aliphatic component having 6 to 12 carbon atoms, and 70 to 90% by mol of an aromatic diol-derived component, the crystalline polyester resin and the amorphous It is preferable that the acid-derived constituent components of the conductive polyester resin each contain the same aromatic component.

  As the weight average molecular weight of the crystalline polyester resin and the amorphous polyester resin, from the viewpoint of low temperature fixability and mechanical strength, the weight average molecular weight of the crystalline polyester resin is 16000-40000 (preferably 17000-40000), The amorphous polyester resin preferably has a weight average molecular weight of 8000 to 26000 (preferably 8000 to 16000).

In addition, in the electrophotographic toner of the present invention, the number average molecular weight Mn (c) and the resin acid value of the crystalline polyester resin can be improved from the viewpoint of improving the toner manufacturability in an aqueous wet process without impairing the chargeability. AV (c) satisfies the relationship of (1.12 × 10 ⁴ ) / Mn (c) <AV (c) <(2.25 × 10 ⁵ ) / Mn (c), and the amorphous polyester resin is The number average molecular weight Mn (a) and the resin acid value AV (a) are (5.61 × 10 ⁴ ) / Mn (a) <AV (a) <(2.25 × 10 ⁵ ) / Mn (a). It is preferable to satisfy the relationship.
By satisfying the relationship between Mn (c) and AV (c) and the relationship between Mn (a) and AV (a), the toner for electrophotography of the present invention can be more uniformly and more easily produced by the emulsion aggregation method. A stable resin emulsion is obtained.
Here, the resin acid value AV is a method specified in JIS standard K0070 “Testing method of acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponified product of chemical products”. It can be determined by neutralizing titration with a KOH alcohol solution using phenolphthalein as an indicator after dissolving in a solvent.

In addition, depending on the synthesis conditions and molecular weight, in order to achieve the above-mentioned relationship between the number average molecular weight and the resin acid value, an acid value imparting treatment after resin synthesis such as adding a polyvalent acid to the resin molecular chain end may be performed. It may be necessary.
Therefore, in view of manufacturability, it can be said that an unnecessary condition for the acid value imparting treatment is desirable. The crystalline polyester resin has a weight average molecular weight of 16000 to 28000, a number average molecular weight Mn (c), and a resin acid value AV (c). Satisfies the relationship of (8.96 × 10 ⁴ ) / Mn (c) <AV (c) <(1.34 × 10 ⁵ ) / Mn (c), and the amorphous polyester resin has a weight average molecular weight. The number average molecular weight Mn (a) and the resin acid value AV (a) are (8.96 × 10 ⁴ ) / Mn (a) <AV (a) <(1.34 × 10 ⁵ ) / It is more preferable to satisfy the relationship of Mn (a).

<Colorant>
There is no restriction | limiting in particular as a coloring agent in the toner for electrophotography of this invention, A well-known coloring agent is mentioned, It can select suitably according to the objective. One type of pigment may be used alone, or two or more types of pigments of the same type may be mixed and used. Two or more different types of pigments may be mixed and used. Specific examples of the colorant include carbon blacks such as furnace black, channel black, acetylene black, and thermal black; inorganic pigments such as bengara, aniline black, bitumen, titanium oxide, and magnetic powder; fast yellow, monoazo Azo pigments such as yellow, disazo yellow, pyrazolone red, chelate red, brilliant carmine (3B, 6B, etc.), para brown; phthalocyanine pigments such as copper phthalocyanine, metal-free phthalocyanine, flavantron yellow, dibromoanthrone orange, perylene red, quinacridone Examples thereof include condensed polycyclic pigments such as red and dioxazine violet.

  Chrome Yellow, Hansa Yellow, Benzidine Yellow, Slen Yellow, Quinoline Yellow, Permanent Orange GTR, Pyrazolone Orange, Vulcan Orange, Watch Young Red, Permanent Red, Dupont Oil Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Various pigments such as red, rose bengal, aniline blue, ultramarine blue, calco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, para brown, acridine, xanthene, azo, Benzoquinone, azine, anthraquinone, dioxazine, thiazine, azomethine, indigo, thioindigo And the like; phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazole type, various dyes such as xanthene. You may mix black pigments, such as carbon black, and dye to such an extent that transparency is not reduced to these colorants. Disperse dyes, oil-soluble dyes, and the like can also be used.

The content of the colorant in the electrophotographic toner of the present invention is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the binder resin, as long as the smoothness of the image surface after fixing is not impaired. Of these numerical ranges, as many as possible are preferable. Increasing the content of the colorant is advantageous in that it can reduce the thickness of the image when obtaining images having the same density, and is effective in preventing offset.
By appropriately selecting the type of the colorant, each color toner such as yellow toner, magenta toner, cyan toner and black toner can be obtained.

<Other ingredients>
The toner for electrophotography of the present invention contains the binder resin and the colorant as essential components, but other components that can be used in conventionally known general toners can be used as appropriate. There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, well-known various additives, such as inorganic fine particles, organic fine particles, a charge control agent, a mold release agent, etc. are mentioned.

The inorganic fine particles are generally used for the purpose of improving toner fluidity. Examples of the inorganic fine particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride. , Bengara, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, silicon oxide, aluminum oxide and the like. Among these, silica fine particles are preferable, and silica fine particles that have been hydrophobized are particularly preferable.
The average primary particle size (number average particle size) of the inorganic fine particles is preferably 1 to 1000 nm, and the addition amount (external addition) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the toner. preferable.

  The organic fine particles are generally used for the purpose of improving cleaning properties and transferability. Examples of the organic fine particles include fine particles such as polystyrene, polymethyl methacrylate, polyvinylidene fluoride, and polyvinyl difluoride.

  The charge control agent is generally used for the purpose of improving chargeability. Examples of the charge control agent include salicylic acid metal salts, metal-containing azo compounds, nigrosine and quaternary ammonium salts.

  The release agent is generally used for the purpose of improving release properties. Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, etc. Mineral / petroleum waxes; ester waxes such as fatty acid esters, montanic acid esters, and carboxylic acid esters. In this invention, these mold release agents may be used individually by 1 type, and may use 2 or more types together.

  The addition amount of these release agents is preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass, and further preferably 5 to 15% by mass with respect to the total amount of toner. When the addition amount of the release agent is less than 0.5% by mass, the effect of addition of the release agent may not be obtained. When the addition amount of the release agent exceeds 50% by mass, the chargeability is increased. The effect of the ink surface is likely to appear, the toner is easily destroyed inside the developing machine, the release agent is spent on the carrier, and the charge is likely to be lowered. Since it tends to become insufficient and the release agent tends to stay in the image, transparency may be deteriorated.

The surface of the toner for electrophotography of the present invention may be covered with a surface layer. The surface layer preferably does not significantly affect the mechanical properties and melt viscoelastic properties of the entire toner. For example, if a non-melted or high melting point surface layer covers the toner thickly, the low-temperature fixability due to the use of the crystalline polyester resin cannot be sufficiently exhibited.
Accordingly, the film thickness of the surface layer is preferably thin, and specifically, it is preferably within the range of 0.001 to 0.5 μm.
In order to form a thin surface layer of 0.001 to 0.5 μm, the surface of particles containing binder resin, colorant, inorganic fine particles added as necessary, and other materials are chemically treated. The method is preferably used.

Examples of the component constituting the surface layer include silane coupling agents, isocyanates, vinyl monomers, and the like, and it is preferable that a polar group is introduced into the component, which is chemically bonded. By doing so, the adhesive force between the toner and the transfer medium such as paper increases.
The polar group may be any polar functional group such as carboxyl group, carbonyl group, epoxy group, ether group, hydroxyl group, amino group, imino group, cyano group, amide group, imide group. , Ester groups, sulfone groups and the like.

Examples of the chemical treatment method include a strong oxidizing substance such as peroxide, a method of oxidizing by ozone oxidation, plasma oxidation, and the like, a method of bonding a polymerizable monomer containing a polar group by graft polymerization, and the like. . By the chemical treatment, the polar group is firmly bonded to the molecular chain of the crystalline resin through a covalent bond.
In the present invention, a chargeable substance may be chemically or physically attached to the toner particle surface. Further, fine particles such as metals, metal oxides, metal salts, ceramics, resins, and carbon black may be externally added for the purpose of improving chargeability, conductivity, powder flowability, lubricity, and the like.

<Physical properties as toner>
In the electrophotographic toner of the present invention, the temperature Tm ″ at which the viscosity of the toner as a whole becomes 103 Pa · s is preferably in the range of 80 to 110 ° C. If the temperature Tm ″ is less than 80 ° C., the heat resistance may not be sufficient, and if left at a high temperature, problems such as blocking may occur. On the other hand, when the temperature Tm ″ exceeds 110 ° C., it may be difficult to obtain a smooth and glossy image surface by fixing. In particular, on the fixed image surface, a step may remain at the boundary between the high density portion and the low density portion.

The volume average particle size of the electrophotographic toner of the present invention is preferably in the range of 6.0 to 16.0 μm, and more preferably in the range of 12.0 to 16.0 μm. If necessary, the particle size distribution may be sharpened through a classification process using an air classifier or the like.
The volume average particle diameter can be measured with an aperture diameter of 50 μm using, for example, a Coulter counter [TA-II] type (manufactured by Coulter). At this time, the measurement is performed after the toner to be measured is dispersed in an electrolyte aqueous solution (isoton aqueous solution) and dispersed by ultrasonic waves for 30 seconds or more.

[Toner Production Method]
The method for producing an electrophotographic toner of the present invention contains at least a binder resin containing a thermoplastic resin and a colorant, and the thermoplastic resin is a mixture obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin. A method for producing an electrophotographic toner comprising a polyester resin, wherein a mixed polyester resin is prepared by melt-mixing the crystalline polyester resin and the amorphous polyester resin in the steps (1) and (2). It has at least a melt mixing step.
As long as the method for producing an electrophotographic toner of the present invention includes the steps (1) and (2), the other steps are not particularly limited, but it is preferable to employ a wet production method because grinding is difficult. Known wet production methods include in-liquid drying method, emulsion aggregation method, melt suspension method, dissolution suspension method and the like. In the electrophotographic toner of the present invention, it is said that the mixed state by melt mixing is maintained. In the sense, a method that does not use an organic solvent is preferred. Therefore, the electrophotographic toner of the present invention can be obtained by using an aqueous melt suspension method and emulsion aggregation method, or a melt suspension method and emulsion aggregation method using a dispersion medium that does not dissolve the resin (for example, silicone oil or liquid paraffin). Is preferred. From the viewpoint of manufacturability / safety and environmental load, it is most preferable to carry out in an aqueous layer.

In order to obtain polyester resin suspended particles and emulsified particles in a practical yield without using a solvent, an ionic hydrophilic group derived from, for example, sulfonic acid is introduced into the polyester resin molecular structure, It is necessary to use a large amount of a dispersion aid and a surfactant, and there are cases where problems remain in chargeability and environmental stability when the toner is formed.
The polyester resin used for the electrophotographic toner of the present invention preferably contains a hydrophilic group derived from bisphenol S. Bisphenol S has a high affinity for water and can reduce the amount of the dispersion aid used in the wet process in the aqueous layer. Further, since the hydrophilic group is nonionic, the environmental stability of the toner is high, which is advantageous for achieving both water layer wet granulation and toner chargeability.

Hereinafter, as an example of a method for producing the electrophotographic toner of the present invention, a production method by a melt suspension method will be described.
In the melt suspension method, a binder resin mainly composed of a mixed polyester resin and a kneaded material such as a colorant are dispersed and suspended in an aqueous dispersion medium using an emulsifier having rotating blades to form particles. At least a dispersion suspension step of preparing the dispersed dispersion.
In such a dispersion suspension step, the kneaded product is dispersed in an aqueous dispersion medium using a disperser, and heated to lower the viscosity of the binder resin to give a shearing force, whereby the suspension of the kneaded product (dispersion) A dispersion of particles). Examples of the disperser include a homogenizer, a homomixer, a pressure kneader, an extruder, and a media disperser.

From the obtained dispersion liquid of dispersed particles, the dispersed particles are separated by the solid-liquid separation process such as filtration, and toner particles are produced through a washing process and a drying process as necessary.
In the dispersion suspension step, a dispersant may be used for stabilizing the suspension and increasing the viscosity of the aqueous dispersion medium. Examples of the dispersant that can be used include water-soluble polymers such as polyvinyl alcohol, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, and sodium polymethacrylate.

Next, as another example of the method for producing the electrophotographic toner of the present invention, a production method by an emulsion aggregation method will be described.
The emulsion aggregation method includes at least an emulsification step of emulsifying a binder resin containing the mixed polyester resin to form emulsion particles, an aggregation step of forming aggregates of the emulsion particles, and heat-aggregating the aggregates. A fusion process.
The emulsified particles in the emulsification step can be prepared by dispersion suspension using a solvent, but in the electrophotographic toner of the present invention, it is preferable to prepare the emulsified particles in water without substantially using a solvent. As the size of the emulsified particles, the average particle size (volume average particle size) is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.03 to 0.6 μm, and 0.03 to 0.4 μm. The range of is more preferable.

  In the emulsification step, a dispersant may be used for stabilizing the emulsified particles. Examples of the dispersant that can be used include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium octadecyl sulfate, sodium oleate, sodium laurate, and potassium stearate; laurylamine acetate, stearylamine acetate, lauryltrimethylammonium Cationic surfactants such as chloride; Zwitterionic surfactants such as lauryl dimethylamine oxide; Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl amine; Phosphoric acid Inorganic salts such as tricalcium, aluminum hydroxide, calcium sulfate, calcium carbonate, and barium carbonate can be used.

  In the aggregation step, the obtained emulsified particles are heated and aggregated at a temperature one step before the melting point of the mixed polyester resin to form an aggregate. Formation of the aggregates of the emulsified particles is performed by acidifying the pH of the emulsion under stirring. As the said pH, the range of 2-6 is preferable, The range of 2.5-5 is more preferable, The range of 2.5-4 is further more preferable.

  In forming the aggregates of the emulsified particles, it is also effective to use a flocculant. As the flocculant usable here, a surfactant having a polarity opposite to that of the surfactant used in the dispersant, an inorganic metal salt, and a metal complex having a valence of 2 or more can be preferably used. In particular, the use of a metal complex is particularly preferable because the amount of the surfactant used can be reduced and the charging characteristics are improved.

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

  In the fusion step, under the same agitation as in the aggregation step, the aggregation suspension is stopped by setting the pH of the aggregate suspension to a range of 3 to 7, at a temperature equal to or higher than the melting point of the polyester resin. The aggregates are fused by heating. As heating temperature at this time, if it is more than melting | fusing point of the said polyester resin, there is no problem. Moreover, as a heating time at this time, it should just be performed to the extent that fusion is fully made, and may be performed for about 0.5 to 10 hours. In this way, a dispersion liquid in which the fused particles are dispersed is obtained.

The fused particle dispersion obtained in the fusing step separates the fusing particles by a solid-liquid separation step such as filtration, and if necessary, undergoes a washing step and a drying step to produce toner particles.
In the case of the emulsion aggregation method described above, the crosslinking step may be introduced after the aggregation step, the fusion step or the fusion step. When the crosslinking step is introduced after the aggregation step, the fusion step, or the fusion step, a solution in which the polymerization initiator is dissolved or emulsified is added to a particle dispersion (resin particle dispersion or the like). A known crosslinking agent, chain transfer agent, polymerization inhibitor or the like may be added to the polymerization initiator for the purpose of controlling the degree of polymerization. The polymerization initiator may be mixed with the polymer in advance before the emulsification step, or may be incorporated into the aggregate in the aggregation step.

[Electrophotographic developer]
The electrophotographic toner of the present invention described above can be used as a two-component developer composed of a carrier and a toner. The electrophotographic developer of the present invention is a two-component developer comprising the electrophotographic toner of the present invention and a carrier. The electrophotographic developer of the present invention (hereinafter sometimes simply referred to as “the developer of the present invention”) will be described below.
The carrier that can be used in the developer of the present invention is not particularly limited, and conventionally known carriers can be used regardless of whether the toner is colored or colorless. For example, a resin-coated carrier having a resin coating layer on the surface of the core material can be exemplified. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

  Examples of the coating resin / matrix resin used for the carrier include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene- Examples thereof include, but are not limited to, an acrylic acid copolymer, a straight silicone resin composed of an organosiloxane bond or a modified product thereof, a fluororesin, a polyester, a polycarbonate, a phenol resin, and an epoxy resin.

Examples of the conductive material include metals such as gold, silver, and copper, and carbon black, as well as titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. It is not limited to.
Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, a magnetic material is used. Preferably there is.
The volume average particle size of the carrier core is preferably 10 to 500 μm, and more preferably 30 to 100 μm.

In order to coat the surface of the core material of the carrier with a resin, there may be mentioned a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent. The solvent is not particularly limited, and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.
Specific resin coating methods include an immersion method in which the carrier core material is immersed in a coating layer forming solution, a spray method in which the coating layer forming solution is sprayed on the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the core material of the carrier and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  The mixing ratio (mass ratio) of the above-described electrophotographic toner of the present invention and the carrier in the developer of the present invention is preferably in the range of toner: carrier = 1: 100-30: 100, 3: 100- A range of 20: 100 is more preferred.

[Image forming method]
Next, the image forming apparatus of the present invention will be described in detail.
Using a latent image forming means for forming an electrostatic latent image on the surface of the photosensitive member and a developer carried on the developer carrying member, the electrostatic latent image formed on the surface of the latent image holding member is developed to form an image. Image forming comprising: developing means for forming; transfer means for transferring the image formed on the surface of the latent image holding member to the surface of the transfer target; and fixing means for thermally fixing the image transferred to the surface of the transfer target And a developer containing the electrophotographic toner of the present invention is used as the developer.
By using the developer containing the electrophotographic toner of the present invention, the image forming apparatus of the present invention is an image forming apparatus that can achieve both heat resistance and low-temperature fixability and that can provide an image with high mechanical strength.

In addition, it is also preferable to include an intermediate transfer member, and once the toner image on the photosensitive member is transferred to the intermediate transfer member, the toner image is transferred from the intermediate transfer member to the surface of the transfer member by a secondary transfer unit.
The photosensitive member is not particularly limited, and a conventionally known one can be adopted without any problem. The photosensitive member may have a single layer structure, or may have a multilayer structure and a function separation type. The material may be an inorganic photoconductor such as selenium or amorphous silicon, or an organic photoconductor (so-called OPC).

Preferably, the latent image forming means has a charging means for charging the surface of the photoreceptor and an exposure means for exposing the charged photoreceptor to form a latent image on the surface. Well-known means such as contact charging means using conductive or semiconductive rollers, brushes, films, rubber blades, non-contact type charging means such as corotron charging and scorotron charging using corona discharge, etc. Can be used.
As the exposure means, conventionally known exposure means such as a combination of a semiconductor laser and a scanning device, a laser ROS comprising an optical system, or an LED head can be used. In order to realize a preferable mode of producing a uniform and high-resolution exposure image, it is preferable to use a laser ROS or an LED head.
Further, the image signal forming unit preferably includes an image signal forming unit. As the image signal forming unit, any conventionally known image signal forming unit can be used as long as a signal capable of forming an image at a desired position on the surface of the transfer target can be formed. You can also use means.

  As the developing unit, a conventionally known developing unit may be used regardless of one-component system or two-component system as long as it has a function of forming a uniform and high-resolution image on the latent image on the surface of the photoreceptor. However, from the viewpoint of good graininess and smooth tone reproduction, a two-component developing means is preferable.

  As the transfer means, for example, using an electrically conductive or semiconductive roller, a brush, a film, a rubber blade or the like to which a voltage is applied, an electric field is created between the photosensitive member and the transfer target or intermediate transfer member, Means for transferring a toner image composed of charged toner particles, a toner image composed of charged toner particles by corona charging the back surface of the transfer medium or intermediate transfer body with a corotron charger or a scorotron charger utilizing corona discharge. Conventionally known means such as means for transferring can be used.

  As the intermediate transfer member, an insulating or semiconductive belt material or a drum-shaped one having an insulating or semiconductive surface can be used. A semiconductive belt material is preferable from the viewpoint of stably maintaining transferability during continuous image formation and reducing the size of the apparatus. As such a belt material, a belt material made of a resin material in which a conductive filler such as carbon fiber is dispersed is known. As this resin, for example, a polyimide resin is preferable.

As the secondary transfer means, for example, a conductive or semiconductive roller, brush, film, rubber blade or the like to which a voltage is applied is used to create an electric field between the intermediate transfer member and the transfer target member, A means for transferring a toner image made up of toner particles, a means for transferring a toner image made up of charged toner particles by corona charging the back surface of the intermediate transfer member with a corotron charger or a scorotron charger using corona discharge, etc. Any known means can be used.
As described above, an image can be formed on the surface of the transfer target.
The transfer medium on which the obtained image is formed is usually continuously conveyed to a fixing unit. As the fixing means and the conveying means for conveying to the fixing means, a publicly known conveying means can be used.

  Further, the transfer material used is not particularly limited, and may be a general copy paper or plain paper, or a resin sheet such as OHP paper. In addition, all the sheet-like media that can form an image with the electrophotographic image forming apparatus using the electrophotographic toner of the present invention are the objects of the transfer target according to the present invention.

Hereinafter, an example of the image forming apparatus of the present invention will be specifically described with reference to FIG. FIG. 1 is a schematic configuration diagram for explaining an example of an image forming apparatus of the present invention. The image forming apparatus shown in FIG. 1 is roughly divided into image forming means (reference numerals 2 to 16) for forming an image and a fixing apparatus (reference numerals 25, 30, and 31) for transferring and fixing the obtained image. And the two are connected by a transport device 19.
In this example, first, the original 1 to be read is irradiated with light by the illumination 2, and the reflected light is read by the color scanner 3. The read signal is sent to an image processing device (image signal forming device) 4 where it is separated into yellow Y, magenta M, cyan C, and black K colors, and an image signal for controlling exposure is exposed to an exposure device ( Is sent to an optical system (ROS) 6 which is an exposure means).

In the optical system (ROS) 6, the laser diode 5 emits light for each color component, and the surface of the organic photoreceptor (photoconductor) 8 is irradiated with image-like light X for each color component. On the other hand, the organic photoreceptor 8 is rotated in the direction of arrow A, and the surface is first uniformly charged by the charger (charging means) 7 and then exposed by the optical system (ROS) 6 described above. Then, it is subjected to development by developing units (developing means) 9 to 11.
For example, taking the yellow Y color as an example, the surface of the organic photoreceptor 8 is irradiated by the optical system (ROS) 6 with the light separated into yellow Y color components by the image processing device 4. The surface of the organic photoreceptor 8 is uniformly charged by the charger 7 in advance, and the portion irradiated with the light is charged to the opposite polarity to form a latent image. Then, the latent image on the surface of the organic photoreceptor 8 is developed by the yellow developing device 9 with yellow Y toner. Further, the organic photoreceptor 8 rotates in the direction of arrow A and is transferred onto the surface of the intermediate transfer belt (intermediate transfer body) 13 by the electrostatic attraction of the transfer corotron 14. The surface of the organic photoreceptor 8 after the transfer is uniformly charged by the charger 7 by further rotation in the direction of the arrow A, and prepares for the next color image formation.

  Subsequent to the yellow Y color, the same operation is performed for each of the magenta M, cyan C, and black K colors, and the latent image is sequentially developed by the magenta developing unit 10, the cyan developing unit 11, and the black developing unit 12, and the intermediate transfer belt. 13 is laminated. The intermediate transfer belt 13 rotates in the direction of arrow B as the organic photoconductor 8 rotates at the time of transferring each color. When the transfer is completed, the intermediate transfer belt 13 rotates in the opposite direction and returns to the original position, and the next color is transferred. The toner image is layered on the previously transferred toner image. When all four colors are stacked, they are rotated as they are in the direction of the arrow B and sent to the nip portion sandwiched between the transfer rolls (secondary transfer means) 15 and 16. In the nip portion, a sheet 17, which is a transfer target for forming an image, is inserted in the direction of arrow C with the intermediate transfer belt 13 in contact with the surface. The laminated toner images are transferred onto the surface of the paper 17 by the electrostatic action of the transfer rolls 15 and 16.

The sheet 17 on which the toner image is transferred is conveyed to the fixing unit 25 by the conveying device 19.
The fixing unit 25 of this example includes a heating roll 30 and a pressure roll 31.
A pressure roll 31 is in pressure contact with the heating roll 30. In this example, a predetermined load is applied by a pressurizing unit (not shown), and is driven to rotate in the direction of arrow D at a predetermined moving speed by a heating roll 30 that is driven to rotate in the direction of arrow C by a driving source (not shown).
The sheet 17 on which the toner image is formed is conveyed by the conveying device 19 and is introduced into the fixing unit 25 having the above configuration.

The sheet 17 on which the toner image is formed (transferred) on the surface is made to face the pressure contact portion (nip portion) between the heating roll 30 and the pressure roll 31 that is pressed against the heating roll 30 so that the toner image faces the heating roll 30 side. Introduced.
Thereafter, in the press contact portion between the heating roll 30 and the pressure roll 31, the toner image is heated and melted and fixed at a temperature of about 120 to 130 ° C. in this example. Further, the sheet 17 is peeled from the heating roll 30 by the waist (rigidity) of the sheet 17 itself.
As described above, the preferred embodiments of the image forming method of the present invention have been described. However, the present invention is not limited to the above-described embodiments. As long as the configuration of the present invention is provided, from the conventionally known knowledge or The configuration of the present invention can be replaced by a technique newly discovered or invented for the present invention.

First, crystalline polyester resins A to E and amorphous polyester resins F to K, which are thermoplastic resins used in the following Examples 1 to 13 and Comparative Examples 1 to 6, are prepared in advance.
(Preparation of crystalline polyester resin A)
A method for producing the crystalline polyester resin A will be described below. In the following, TPA is dimethyl terephthalate, ND is 1,9-nonanediol, and BPS is a bisphenol S ethylene oxide adduct.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 152 parts by mass of 1,9-nonanediol, 16.9 parts by mass of bisphenol S ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst Then, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and stirred at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled and the reaction was stopped to obtain a crystalline polyester resin A having the following composition ratio.
-Composition ratio of crystalline polyester resin A TAP / ND / BPS = 100/95/5 (molar ratio)

The obtained crystalline polyester resin A has a weight average molecular weight (Mw) of 23,000 and a number average molecular weight (Mn) of molecular weight measurement (polystyrene conversion) by gel permeation chromatography (solvent: tetrahydrofuran, the same applies hereinafter). 12000.
Further, when the melting point (Tm) of the crystalline polyester resin A was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak and the peak top temperature was 92 ° C. It was.

(Preparation of crystalline polyester resin B)
A method for producing the crystalline polyester resin B will be described below. In the following, BPA is a bisphenol A ethylene oxide adduct.
In a heat-dried three-necked flask, 194 parts by weight of dimethyl terephthalate, 152 parts by weight of 1,9-nonanediol, 15.8 parts by weight of bisphenol A ethylene oxide adduct, and 0.15 parts by weight of dibutyltin oxide as a catalyst After that, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and stirred at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled and the reaction was stopped to obtain a crystalline polyester resin B having the following composition ratio.
-Composition ratio of crystalline polyester resin B TPA / ND / BPA = 100/95/5 (molar ratio)

The obtained crystalline polyester resin B had a weight average molecular weight (Mw) of 22000 and a number average molecular weight (Mn) of 10900 as measured by gel permeation chromatography (polystyrene conversion).
Further, when the melting point (Tm) of the crystalline polyester resin B was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak and the peak top temperature was 94 ° C. It was.

(Preparation of crystalline polyester resin C)
A method for producing the crystalline polyester resin C will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 144 parts by mass of 1,9-nonanediol, 31.6 parts by mass of bisphenol A ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst After that, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and stirred at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled and the reaction was stopped to obtain a crystalline polyester resin C having the following composition ratio.
・ Composition ratio of crystalline polyester resin C
TPA / ND / BPA = 100/90/10 (molar ratio)

The obtained crystalline polyester resin C had a weight average molecular weight (Mw) of 22,000 and a number average molecular weight (Mn) of 11,000 as measured by gel permeation chromatography.
Further, when the melting point (Tm) of the crystalline polyester resin C was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak and the peak top temperature was 90 ° C. It was.

(Preparation of crystalline polyester resin D)
A method for producing the crystalline polyester resin D will be described below.
194 parts by mass of dimethyl terephthalate, 160 parts by mass of 1,9-nonanediol, and 0.15 parts by mass of dibutyltin oxide as a catalyst were placed in a heat-dried three-necked flask, and then the air in the container was reduced by a vacuum operation. The mixture was placed in an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 5 hours with mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled and the reaction was stopped to obtain a crystalline polyester resin D having the following composition ratio.
-Composition ratio of crystalline polyester resin D TAP / ND = 100/100 (molar ratio)

The obtained crystalline polyester resin D had a weight average molecular weight (Mw) of 24,000 and a number average molecular weight (Mn) of 13,000, as measured by gel permeation chromatography.
Further, when the melting point (Tm) of the crystalline polyester resin D was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, it had a clear peak and the peak top temperature was 95 ° C. It was.

(Preparation of crystalline polyester resin E)
A method for producing the crystalline polyester resin E will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 152 parts by mass of 1,9-nonanediol, 15.8 parts by mass of bisphenol A ethylenelenoxide adduct, 136 parts by mass of ethylene glycol, and as a catalyst After adding 0.15 parts by mass of dibutyltin oxide, the air in the container was put into an inert atmosphere with nitrogen gas by a depressurization operation, and the mixture was stirred at 180 ° C. for 5 hours by mechanical stirring. The methanol produced by the reaction and excess ethylene glycol are distilled off under reduced pressure, and then gradually heated to 220 ° C. under reduced pressure and stirred for 2 hours. Was stopped to obtain a crystalline polyester resin E having the following composition ratio.
-Composition ratio of crystalline polyester resin E TPA / ND / BPA = 100/95/5 (molar ratio)

The obtained crystalline polyester resin E had a weight average molecular weight (Mw) of 43,000 and a number average molecular weight (Mn) of 22,000 as measured by gel permeation chromatography.
Further, the melting point (Tm) of the crystalline polyester E was measured by the above-described measurement method using a differential scanning calorimeter (DSC). As a result, the crystalline polyester E had a clear peak and the peak top temperature was 96 ° C. .
Here, the produced crystalline polyesters A to E are shown in Table 1.

(Preparation of amorphous polyester resin F)
A method for producing the crystalline polyester resin F will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 40 parts by mass of 1,9-nonanediol, 221 parts by mass of bisphenol A ethylene oxide adduct, 17 parts by mass of bisphenol S ethylene oxide adduct, Then, 0.15 parts by mass of dibutyltin oxide was added, and the air in the container was put into an inert atmosphere with nitrogen gas by a depressurization operation, followed by stirring at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, and the reaction was stopped to obtain a crystalline polyester resin F having the following composition ratio.
-Composition ratio of crystalline polyester resin F TPA / ND / BPA / BPS = 100/25/70/5 (molar ratio)

The obtained crystalline polyester resin F had a weight average molecular weight (Mw) of 12,500 and a number average molecular weight (Mn) of 5,800 as determined by molecular weight measurement (polystyrene conversion) by gel permeation chromatography.
In addition, when the melting point (Tm) of the amorphous polyester resin F was measured using a differential scanning calorimeter (DSC) by the above-described measuring method, no clear peak was shown, and a stepwise endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 55 ° C.

(Preparation of amorphous polyester resin G)
A method for producing the crystalline polyester resin G will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 40 parts by mass of 1,9-nonanediol, 254 parts by mass of a bisphenol S ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst After putting, the air in the container was brought into an inert atmosphere with nitrogen gas by a depressurization operation, and stirred at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled and the reaction was stopped to obtain a crystalline polyester resin G having the following composition ratio.
-Composition ratio of crystalline polyester resin G TPA / ND / BPS = 100/25/75

The obtained amorphous polyester resin G had a weight average molecular weight (Mw) of 12,500 and a number average molecular weight (Mn) of 5,800 as determined by gel permeation chromatography.
Further, when the melting point (Tm) of the amorphous polyester resin G was measured using a differential scanning calorimeter (DSC) by the above-described measurement method, no clear peak was shown and a step-like endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 50 ° C.

(Preparation of amorphous polyester resin H)
A method for producing the crystalline polyester resin H will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 40 parts by mass of 1,9-nonanediol, 237 parts by mass of bisphenol A ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst After putting in, the air in a container was made into inert atmosphere with nitrogen gas by pressure reduction operation, and it stirred at 180 degreeC by mechanical stirring for 5 hours.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became a viscous state, it was air-cooled, the reaction was stopped, and a crystalline polyester resin H having the following composition ratio was obtained.
-Composition ratio of crystalline polyester resin H TPA / ND / BPA = 100/25/75

The obtained amorphous polyester resin H has a weight average molecular weight (Mw) of 13,000 and a number average molecular weight (by molecular weight measurement (polystyrene conversion) by gel permeation chromatography). Mn) was 6000.
Further, when the melting point (Tm) of the amorphous polyester resin H was measured using a differential scanning calorimeter (DSC) by the above-described measuring method, a clear peak was not shown, and a stepwise endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 58 ° C.

(Preparation of amorphous polyester resin I)
A method for producing the crystalline polyester resin I will be described below.
194 parts by mass of dimethyl terephthalate, 338 parts by mass of bisphenol S ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst were placed in a heat-dried three-necked flask, and then the air in the container was reduced by a pressure reduction operation. The mixture was placed in an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 5 hours with mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became viscous, it was air-cooled, and the reaction was stopped to obtain a crystalline polyester resin I having the following composition ratio.
-Composition ratio of crystalline polyester resin I TPA / BPS = 100/100

The obtained amorphous polyester resin I had a weight average molecular weight (Mw) of 12000 and a number average molecular weight (Mn) of 5600 as measured by gel permeation chromatography (polystyrene conversion).
Further, when the melting point (Tm) of the amorphous polyester resin I was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, a clear peak was not shown, and a stepwise endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 98 ° C.

(Preparation of amorphous polyester resin J)
A method for producing the crystalline polyester resin J will be described below.
In a heat-dried three-necked flask, 194 parts by mass of dimethyl terephthalate, 316 parts by mass of bisphenol A ethylene oxide adduct, and 0.15 parts by mass of dibutyltin oxide as a catalyst were added, and the air in the container was reduced by a pressure reduction operation. The mixture was placed in an inert atmosphere with nitrogen gas, and stirred at 180 ° C. for 5 hours with mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became a viscous state, it was air-cooled, the reaction was stopped, and a crystalline polyester resin J having the following composition ratio was obtained.
-Composition ratio of crystalline polyester resin J TPA / BPA = 100/100

The obtained amorphous polyester resin J had a weight average molecular weight (Mw) of 13,000 and a number average molecular weight (Mn) of 6000, as determined by gel permeation chromatography.
Further, when the melting point (Tm) of the amorphous polyester C was measured by a differential scanning calorimeter (DSC) by the above-described measuring method, no clear peak was shown, and a stepwise endothermic change was confirmed. . The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 82 ° C.

(Preparation of amorphous polyester resin K)
A method for producing the crystalline polyester resin K will be described below. In the following, CHDM is cyclohexane dimethal.
194 parts by mass of dimethyl terephthalate, 253 parts by mass of bisphenol A ethylene oxide adduct, 28.8 parts by mass of cyclohexanedimethanol, and 0.15 parts by mass of dibutyltin oxide as a catalyst are placed in a heat-dried three-necked flask. After that, the air in the container was brought into an inert atmosphere with nitrogen gas by depressurization, and stirred at 180 ° C. for 5 hours by mechanical stirring.
Thereafter, the temperature was gradually raised to 230 ° C. under reduced pressure, and the mixture was stirred for 2 hours. When it became a viscous state, it was air-cooled, and the reaction was stopped to obtain a crystalline polyester resin K having the following composition ratio.
-Composition ratio of crystalline polyester resin K TPA / BPA / CHDM = 100/80/20

The obtained amorphous polyester resin K had a weight average molecular weight (Mw) of 13,000 and a number average molecular weight (Mn) of 6000, as determined by gel permeation chromatography.
Further, when the melting point (Tm) of the amorphous polyester resin K was measured using a differential scanning calorimeter (DSC) by the above-described measurement method, no clear peak was shown, and a step-like endothermic change was confirmed. It was. The glass transition point (Tg) at the midpoint of the stepwise endothermic change was 65 ° C.
Here, Table 2 shows a list of the produced amorphous polyester resins F to K.

<Example 1>
(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin F are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin F are charged into an extrusion kneader, and the melt mixing time is fixed at 5 minutes. The temperature is raised for each sample in degrees Celsius to produce a mixed polyester resin, and for each of the obtained mixed polyester resins, a melt mixing temperature T _{0 at} which the luminous reflectance Y becomes 1.5% is obtained by the procedure described later. It was. As a result, t ₀ = 5 [min] and T ₀ = 185 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin F, respectively, and charged into an extrusion kneader set at a temperature of 190 ° C. [Minute] Melting and mixing were performed to obtain mixed polyester resins (thermoplastic resins) used for yellow toner, magenta toner, cyan toner, and black toner, respectively. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 90 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : 5 parts by mass of carbon black

The luminous reflectance Y was measured according to the following procedure.
The mixed polyester resin to be measured was applied on a color OHP sheet manufactured by Fuji Xerox Co., Ltd. so as to have a thickness of 20 μm, thereby creating a transparent image.
A cover glass for microscopic observation was placed on the front and back surfaces of the transparent image, and the gap between the transparent image and the cover glass was filled with tetradecane.
This was measured with X-rite 968 on a light trap to measure Y ′.
On the other hand, a cover glass for microscopic observation was placed on the front and back surfaces of the OHP film not coated with the mixed polyester resin, the gap between the image and the cover glass was filled with tetradecane, and Y0 was measured in the same procedure.
Y was calculated by Y′−Y0.
The viscosity of the resin was measured using a rotating plate rheometer (Rheometers, Inc .: RDAII) at an angular velocity of 1 rad / s.

(Melt dispersion granulation)
Each of the mixed polyester resins used for the obtained yellow toner, magenta toner, cyan toner, and black toner (hereinafter referred to as “four colors”) is 5% with respect to a 3 mass% carboxymethylcellulose aqueous solution heated to 98 ° C. An amount of mass% was added, and dispersion was performed for 1 hour at a rotational speed of 4000 rpm using an Ultra Turrax T50 (manufactured by IKA-Labortenik).
This was further returned to room temperature, diluted three times, adjusted to pH 9.5 with a 0.2 M sodium hydroxide aqueous solution, and stirred with a stirrer at 200 rpm for 1 hour to obtain four color dispersions.

After filtering each of the obtained four color dispersions, the particles on the filter paper were washed with water, and further adjusted to pH 4.0 with 0.2M nitric acid, and then stirred for 1 hour at 200 rpm with a stirrer. Stir. Thereafter, the particles were collected again by filtration, sufficiently washed with water, and decompressed and freeze-dried.
The dried dispersed particles were classified with a wind classifier to prepare fine particles of four colors (yellow toner, magenta toner, cyan toner, and black toner) having an average particle diameter d50 of 6 μm.
The average particle diameter of the toner was measured using a Coulter counter, and a weight average d50 was applied.

(Developer)
From the toner of the four colors (yellow, magenta, cyan and black) of Example 1, the following two kinds of inorganic fine particles A and B were adhered to 100 parts by mass of the obtained four colors of fine particles with a high speed mixer. Toner J1 was obtained.
Inorganic fine particles A: SiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.05 μm, added amount 1.0 part by mass)
Inorganic fine particle B: TiO ₂ (surface hydrophobized with silane coupling agent, average particle size 0.02 μm, refractive index 2.5, added amount 1.0 part by mass)
Further, 100 parts by mass of the same carrier as the black developer for Acolor 635 (manufactured by Fuji Xerox Co., Ltd.) was mixed with 8 parts by mass of each of the four color toners J1 obtained above. A two-component developer D1 composed of a two-component developer of four colors (yellow, magenta, cyan and black) was produced.

-Image output-
Using the image forming apparatus shown in FIG. 1, an image (an evaluation image and a portrait image of each color Cin100) was formed on a transfer target (color paper (J paper) manufactured by Fuji Xerox Co., Ltd.) using the two-component developer D1. . In addition, the heating roll 30 and the pressure roll 31 used what provided the silicon rubber layer of thickness 2mm on the core material made from aluminum, and have arrange | positioned the halogen lamp as a heat source in those centers. Both roll surface temperatures were varied between 100 ° C and 170 ° C. The fixing speed was 30 mm / second.

<Example 2>
In the production of the two-component developer D1 in Example 1, a two-component developer D2 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D2 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin G are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin G are melt-mixed for 5 minutes, and the mixed polyester resin is obtained. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 170 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin G, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 190 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 105 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 3>
In the production of the two-component developer D1 in Example 1, a two-component developer D3 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D3 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (5 minutes in this example) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. For each of the obtained mixed polyester resins, the luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 170 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin A and 50 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 190 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 85 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 4>
In the production of the two-component developer D1 in Example 1, a two-component developer D4 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D4 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (5 minutes in this example) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes, and the mixed polyester resin is obtained. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 185 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 190 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 90 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 5>
In the production of the two-component developer D1 in Example 1, a two-component developer D5 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D5 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 40 parts by mass of the crystalline polyester resin B and 60 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 40 parts by mass of the crystalline polyester resin B and 60 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. For each of the obtained mixed polyester resins, the luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 190 [° C.].

Next, the following colorants were added to 40 parts by mass of the crystalline polyester resin B and 60 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] by an extrusion kneader set at a temperature of 190 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 95 degreeC, and the luminous reflectance Y was 1.5% or less.
-Synthetic polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Synthetic polyester resin for magenta toner: 4 parts by mass of pigment red-Synthetic polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Synthetic polyester resin for black toner : Carbon black 5 parts by mass

<Example 6>
In the production of the two-component developer D1 in Example 1, a two-component developer D6 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D6 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 60 parts by mass of the crystalline polyester resin B and 40 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 60 parts by mass of the crystalline polyester resin B and 40 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes, and the mixed polyester resin is obtained. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 180 [° C.].

Next, the following colorants were added to 60 parts by mass of the crystalline polyester resin B and 40 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 190 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 90 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : 5 parts by mass of carbon black

<Example 7>
In the production of the two-component developer D1 in Example 1, a two-component developer D7 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D7 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin C and 50 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (5 minutes in this example) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin C and 50 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 165 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin C and 50 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 180 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 85 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 8>
In the production of the two-component developer D1 in Example 1, a two-component developer D8 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as described below. An image was formed in the same manner as in Example 1 except that the two-component developer D8 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 200 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 200 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 90 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : 5 parts by mass of carbon black

<Example 9>
In the production of the two-component developer D1 in Example 1, a two-component developer D9 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D9 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H are melt-mixed under the following conditions, respectively, and the resulting polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 200 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin H, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 210 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 90 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 10>
In the production of the two-component developer D1 in Example 1, a two-component developer D10 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D10 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin I are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (5 minutes in this example) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin I are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 195 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin B and 50 parts by mass of the amorphous polyester resin I, respectively, and melt mixed for 10 [min] in an extrusion kneader set at a temperature of 200 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 105 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 11>
In the production of the two-component developer D1 in Example 1, a two-component developer D11 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as described below. An image was formed in the same manner as in Example 1 except that the two-component developer D11 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin K are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin are melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 220 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin K, respectively, and melt-mixed for 10 [min] by an extrusion kneader set at a temperature of 220 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 105 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Example 12>
In the production of the two-component developer D1 in Example 1, a two-component developer D12 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D12 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin J are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin J are melt-mixed for 5 minutes, and the mixed polyester resin is obtained. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 210 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin D and 50 parts by mass of the amorphous polyester resin J, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 210 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 95 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : 5 parts by mass of carbon black

<Example 13>
In the production of the two-component developer D1 in Example 1, a two-component developer D13 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to the mixed polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D13 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J were melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 190 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J, respectively, and melt-mixed for 10 [min] by an extrusion kneader set at a temperature of 210 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 105 degreeC, and the luminous reflectance Y was 1.5% or less.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Comparative Example 1>
In the production of the two-component developer D1 in Example 1, a two-component developer D14 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a mixed polyester resin produced as described below. An image was formed in the same manner as in Example 1 except that the two-component developer D14 was used instead of the component developer D1.

(Production of mixed polyester resin)
In advance, 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J are melt-mixed under the following conditions, respectively, and the resulting polyester polyester resin has a luminous reflectance Y of 1.5%. The mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] (in this example, 5 minutes) were determined. Specifically, in the same procedure as in Example 1 using an extrusion kneader, 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J were melt-mixed for 5 minutes to obtain a mixed polyester resin. Obtained. With respect to each of the obtained mixed polyester resins, luminous reflectance Y in the case of a film having a thickness of 20 μm was measured by the above procedure, and t ₀ [min] and T ₀ [° C.] were obtained. As a result, t ₀ = 5 [min] and T ₀ = 190 [° C.].

Next, the following colorants were added to 50 parts by mass of the crystalline polyester resin E and 50 parts by mass of the amorphous polyester resin J, respectively, and melt-mixed for 10 [min] in an extrusion kneader set at a temperature of 185 [° C.]. Thus, a mixed polyester resin used for yellow toner, magenta toner, cyan toner, and black toner was obtained. In addition, melting | fusing point Tm of each obtained mixed polyester-type resin was 115 degreeC.
・ Mixed polyester resin for yellow toner: 5 parts by mass of benzidine yellow ・ Mixed polyester resin for magenta toner: 4 parts by mass of pigment red ・ Mixed polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue ・ Mixed polyester resin for black toner : Carbon black 5 parts by mass

<Comparative example 2>
In the production of the two-component developer D1 in Example 1, a two-component developer D15 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D15 was used instead of the developer D1.

(Production of polyester resin)
The following colorant was added to 100 parts by mass of the amorphous polyester resin A, and melted and mixed for 10 minutes with an extrusion kneader set at a temperature of 185 [° C.] to obtain yellow toner, magenta toner, cyan toner, And a polyester resin used for black toner. In addition, melting | fusing point Tm of the obtained mixed polyester-type resin was 85 degreeC.
-Polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Polyester resin for magenta toner: 4 parts by mass of polyester red-Polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Polyester resin for black toner: Carbon black 5 Parts by mass

<Comparative Example 3>
In the production of the two-component developer D1 in Example 1, a two-component developer D16 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D16 was used instead of the developer D1.

(Production of polyester resin)
The following colorant was added to 100 parts by mass of the amorphous polyester resin D, and melted and mixed for 10 minutes with an extrusion kneader set at a temperature of 185 [° C.] to obtain yellow toner, magenta toner, cyan toner, And a polyester resin used for black toner. In addition, melting | fusing point Tm of the obtained polyester-type resin was 95 degreeC.
-Polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Polyester resin for magenta toner: 4 parts by mass of polyester red-Polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Polyester resin for black toner: Carbon black 5 Parts by mass

<Comparative example 4>
In the production of the two-component developer D1 in Example 1, a two-component developer D17 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D17 was used instead of the developer D1.

(Production of polyester resin)
The following colorant was added to 100 parts by mass of the amorphous polyester resin D, and melted and mixed for 10 minutes with an extrusion kneader set at a temperature of 185 [° C.] to obtain yellow toner, magenta toner, cyan toner, And a polyester resin used for black toner. In addition, melting | fusing point Tm of the obtained polyester-type resin was 105 degreeC.
-Polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Polyester resin for magenta toner: 4 parts by mass of polyester red-Polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Polyester resin for black toner: Carbon black 5 Parts by mass

<Comparative Example 5>
In the production of the two-component developer D1 in Example 1, a two-component developer D18 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D18 was used instead of the developer D1.

(Production of polyester resin)
The following colorants were respectively added to 100 parts by mass of the amorphous polyester resin J, and melted and mixed for 10 minutes with an extrusion kneader set at a temperature of 185 [° C.] to obtain yellow toner, magenta toner, cyan toner, And a polyester resin used for black toner. In addition, melting | fusing point Tm of the obtained polyester-type resin was 135 degreeC.
-Polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Polyester resin for magenta toner: 4 parts by mass of polyester red-Polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Polyester resin for black toner: Carbon black 5 Parts by mass

<Comparative Example 6>
In the production of the two-component developer D1 in Example 1, a two-component developer D19 was produced in the same manner as in Example 1 except that the mixed polyester resin was changed to a polyester resin produced as follows. An image was formed in the same manner as in Example 1 except that the two-component developer D19 was used instead of the developer D1.

(Production of polyester resin)
The following colorant was added to 100 parts by mass of the amorphous polyester resin K, and melted and mixed for 10 minutes with an extrusion kneader set at a temperature of 185 [° C.] to obtain yellow toner, magenta toner, cyan toner, And a polyester resin used for black toner. In addition, melting | fusing point Tm of the obtained polyester-type resin was 115 degreeC.
-Polyester resin for yellow toner: 5 parts by mass of benzidine yellow-Polyester resin for magenta toner: 4 parts by mass of polyester red-Polyester resin for cyan toner: 4 parts by mass of phthalocyanine blue-Polyester resin for black toner: Carbon black 5 Parts by mass

  Table 3 shows the melt mixing conditions for preparing the mixed polyester resin or polyester resin in each Example and Comparative Example.

<Evaluation test>
The following evaluation tests were performed on the toners and color images of the examples and comparative examples.
The results are shown in Table 4.

(Manufacturability evaluation)
-Dispersibility-
In the preparation of the toner of each example or comparative example, when the mixed polyester resin or polyester resin used as the main component was placed in a dispersing device (Ultra Turrax T50) and dispersed to obtain a dispersion (by filter paper) (The state immediately before filtration), the ratio of the residue adhering to the container wall surface and bottom surface of the dispersion device without dispersion to the amount of the mixed polyester resin or polyester resin initially placed in the dispersion device (dispersion residue [mass% ]). The dispersibility was evaluated from the ratio of the dispersion residue according to the following evaluation criteria. This evaluation of dispersibility can be an index for evaluating manufacturability.
○: Less than 20% by mass Δ: 20% by mass or more, less than 40% by mass ×: 40% by mass or more

(Durability evaluation)
-Mechanical strength-
The evaluation images obtained in the examples and comparative examples were wound around metal rolls having different radii, the minimum radius that did not cause cracks was measured, and the mechanical strength was evaluated from the measured minimum radius according to the following criteria.
○: The minimum radius is less than 10 mm.
Δ: The minimum radius is 10 mm or more and less than 30 mm.
X: 30 mm or more.

-Heat resistance-
After the surfaces of the images for evaluation obtained in Examples and Comparative Examples were brought into contact with each other and overlapped, a weight of 30 g weight / cm ² was applied, and then placed in a constant temperature layer maintained at a constant temperature, after 3 days had passed. Returning to room temperature of about 22 ° C., the superposed surface and the surface were peeled off. This test was repeated while changing the temperature, and the heat resistance was evaluated according to the following criteria from the temperature at which the image surface was destroyed.
○: The temperature at which the image surface was destroyed was 60 ° C. or higher.
(Triangle | delta): The temperature which the image surface destroyed was 45 degreeC or more and less than 60 degreeC.
X: The temperature at which the image surface was destroyed was less than 45 ° C.

<Low-temperature fixability test>
-Fixability-
In the examples and comparative examples, the image for evaluation that has not yet been fixed is fixed by the fixing device for A color full-color copying machine (manufactured by Fuji Xerox Co., Ltd.) with the fixing temperature set to 130 ° C. The image surface of each fixed image was valley-folded, the degree of peeling of the image at the crease portion was visually observed, and the fixability was evaluated according to the following criteria. If the fixing temperature at which the image is peeled is 130 ° C. or lower, it can be said that the low-temperature fixing property is excellent.
○: No peeling was observed in the image of the fold.
Δ: Peeling was observed only in the image of the crease portion.
X: When the fold was opened, the image was widely peeled off.

-Peelability-
The peelability was evaluated according to the following criteria from the fixed image at the time of fixing.
○: Paper was passed through without sticking to the heating roll.
Δ: Once attached to the heating roll, it peeled off before being wound around the roll.
X: Wound on a heating roll.

-Solidification speed-
The solidification rate was evaluated according to the following criteria.
○: The evaluation image output from the image forming apparatus is completely solidified, and no fingerprints are attached even if it is touched with the hand.
Δ: Although the evaluation image output from the image forming apparatus was not completely solidified, it could be output without defects on the image surface, and there was no problem with the smoothness of the image surface even when the next output image overlapped.
X: The image output from the image forming apparatus was not solidified for evaluation, the image surface was not smooth, and uneven gloss occurred. Alternatively, even after passing the peeling roll, the image was stuck to the belt and could not be peeled off.

(Evaluation results)
From the above results, the following can be understood.
The images obtained in Examples 1 to 13 indicate that an image satisfying all of the mechanical strength, heat resistance, and low-temperature fixability is obtained without impairing the dispersibility. In particular, in Examples 1 to 3, the dispersibility was also good.
The image obtained in Comparative Example 1 was poor in low-temperature fixability. Further, the fixed image obtained by raising the fixing temperature was cracked by slight bending.
Although the image obtained in Comparative Example 2 could be peeled off from the heating roll, the surface layer was not completely solidified when the next image was output and overlapped, resulting in uneven gloss on the image surface.
The image obtained in Comparative Example 3 could not be peeled off from the heating roll. After passing through the heating roll, the image was peeled off from the belt by hand. As a result, the surface of the image was not smooth and uneven gloss occurred.
The image obtained in Comparative Example 4 could not be peeled from the heating roll. When the image was peeled off from the belt by hand after passing through the heating roll, the surface of the image was not smooth and gloss unevenness occurred.
The image obtained in Comparative Example 5 had poor fixability. Further, the fixed image obtained by raising the fixing temperature was cracked by slight bending.
The image obtained in Comparative Example 6 was poor in fixability and heat resistance. Further, the fixed image obtained by raising the fixing temperature was cracked by slight bending.

1 is a schematic configuration diagram for explaining an example of an image forming apparatus of the present invention.

Explanation of symbols

1: Document 2: Illumination 3: Color scanner 4: Image processing device 5: Laser diode 6: Optical system (ROS)
7: Charger 8: Organic photoreceptor 9: Yellow developer 10: Magenta developer 11: Cyan developer 12: Black developer 13: Intermediate transfer belt 14: Transfer corotron 15, 16: Transfer roll 17: Paper 19: Conveyance Device 25: Fixing means 30: Heating roll 31: Pressure roll

Claims (4)

An electrophotographic toner containing at least a binder resin containing a thermoplastic resin and a colorant,
The thermoplastic resin includes a mixed polyester resin obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin, and the melt-mixing of the crystalline polyester resin and the amorphous polyester resin includes the following (1) and (2 The toner for electrophotography, which is formed by the process of
(1) Luminous reflectance Y when a mixed polyester resin obtained by melt-mixing the crystalline polyester resin and the amorphous polyester resin into a film having a thickness of 20 [μm] is 1.5 in advance. The melt mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min], which are [%], are determined.
(2) Next, the crystalline polyester resin and the amorphous polyester resin are melted under the conditions of melt mixing temperature: T _{0 to} T ₀ +20 [° C.] and melt mixing time: t _{0 to} t ₀ +10 [min]. Mix. An electrophotographic developer comprising a carrier and a toner,
An electrophotographic developer, wherein the toner is the electrophotographic toner according to claim 1. A latent image forming unit that forms an electrostatic latent image on the surface of the latent image holding member and a developer carried on the developer carrying member are used to develop the electrostatic latent image formed on the surface of the latent image holding member. Developing means for forming a toner image; transfer means for transferring the toner image formed on the surface of the latent image holding body to the surface of the transfer target; and fixing means for thermally fixing the toner image transferred to the surface of the transfer target; An image forming apparatus comprising:
The image forming apparatus according to claim 1, wherein the developer includes the electrophotographic toner according to claim 1. A method for producing an electrophotographic toner comprising at least a binder resin containing a thermoplastic resin and a colorant, wherein the thermoplastic resin comprises a mixed polyester resin obtained by melt-mixing a crystalline polyester resin and an amorphous polyester resin. Because
An electrophotographic toner comprising at least a melt-mixing step of preparing a mixed polyester resin by melt-mixing the crystalline polyester resin and the amorphous polyester resin by the following steps (1) and (2) Manufacturing method.
(1) Luminous reflectance Y [%] when a mixed polyester resin obtained by melt-mixing the crystalline polyester resin and the amorphous polyester resin is formed into a film having a thickness of 20 [μm] in advance. The melt mixing temperature: T ₀ [° C.] and the melt mixing time: t ₀ [min] are determined to be 1.5%.
(2) Next, the crystalline polyester resin and the amorphous polyester resin are melted under the conditions of melt mixing temperature: T _{0 to} T ₀ +20 [° C.] and melt mixing time: t _{0 to} t ₀ +10 [min]. Mix.

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