JP2022191480A - Toner for electrostatic charge image development, method for manufacturing toner for electrostatic charge image development, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a toner for electrostatic charge image development with which an image formed on a recording medium is not easily chipped, compared with a case where a mixture ratio of a crystalline polyester resin and an amorphous polyester resin is determined so that a value obtained by dividing a ratio between the loss elastic modulus and the storage elastic modulus of the toner for electrostatic charge image development at 30°C after heating and fusion and before heat treatment is performed at 50°C or more and 60°C or less by a ratio between the loss elastic modulus and the storage elastic modulus of the toner for electrostatic charge image development at 30°C after the heating and fusion and after the heat treatment is performed at 50°C or more and 60°C or less becomes smaller than 2 or larger than 6.

SOLUTION: A method for manufacturing a toner for electrostatic charge image development includes: an aggregation step of, in a fluid dispersion in which a crystalline polyester resin and an amorphous polyester resin are dispersed, aggregating the crystalline polyester resin and the amorphous polyester resin to obtain aggregated particles; and a formation step of heating and fusing the aggregated particles to form toner particles that are a viscoelastic body after the heating and fusion and change from a more viscous state to a more elastic state when heat treatment is performed at 50°C or more and 60°C or less.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2023,JPO&INPIT

Description

The present invention relates to a toner for developing an electrostatic charge image, a method for producing the toner for developing an electrostatic charge image, and an image forming apparatus.

Japanese Patent Application Laid-Open No. 2002-200002 discloses that the yellow toner is set so that the storage elastic modulus after the heat treatment is smaller than the storage elastic modulus before the heat treatment in a temperature range equal to or higher than the softening point.

JP-A-2004-163571

In an image forming system or the like, for example, toner for developing an electrostatic charge image is placed on a recording medium, the recording medium on which the toner is placed is heated and pressed to fix the toner on the recording medium, and then the recording medium is discharged. There is As the electrostatic charge image developing toner, a toner containing heat-melting resin and being a viscoelastic body after heat-melting is sometimes used.

Here, after the toner is heated and melted by fixing on the recording medium, the toner may change from a more viscous state to a more elastic state.
If the rate of change in the viscoelasticity of the toner is excessively high, for example, the toner may become more elastic and more fragile immediately after being heated and melted. In this case, after the recording medium is fixed and before it is ejected, the image on the recording medium is chipped due to external force acting on the image (for example, when the recording medium is bent by a post-processing device, the recording medium is bent). There is a risk that the image located at the bent portion will be missing).

Further, if the rate of change in the viscoelasticity of the toner is too small, the recording medium may be ejected while the viscosity of the toner is still high. In this case, the image on the discharged recording medium moves to another part (for example, the image on one discharged recording medium moves to another recording medium that is discharged and stacked next), so that the recording Images on the media may be lost.

An object of the present invention is to determine the ratio of the loss elastic modulus to the storage elastic modulus of a toner for electrostatic image development at 30° C. after heat melting and before heat treatment at 50° C. or more and 60° C. or less. and the value obtained by dividing the ratio of the loss elastic modulus to the storage elastic modulus of the electrostatic image developing toner at 30° C. after heat treatment at 50° C. to 60° C. is less than 2 or more than 6 To provide a toner for developing an electrostatic charge image in which an image formed on a recording medium is less likely to be chipped compared to the case where the mixing ratio of a crystalline polyester resin and an amorphous polyester resin is determined so as to increase the .

In the invention according to claim 1, in a dispersion liquid in which the crystalline polyester resin and the amorphous polyester resin are dispersed, the crystalline polyester resin and the amorphous polyester resin are aggregated to obtain aggregated particles. and the agglomerated particles are heated and fused to form a viscoelastic body after heating and melting, which changes from a viscous state to a more elastic state when heat treatment is performed at 50° C. or higher and 60° C. or lower. and a forming step of forming toner particles, wherein the mixing ratio of the crystalline polyester resin and the amorphous polyester resin in the aggregation step is after heat melting and heat treatment at 50° C. or higher and 60° C. or lower. The ratio of the loss elastic modulus and the storage elastic modulus at 30 ° C. before melting is the ratio of the loss elastic modulus and the storage elastic modulus at 30 ° C. after heat melting and heat treatment at 50 ° C. or higher and 60 ° C. or lower. A method for producing a toner for developing an electrostatic charge image, characterized in that the value obtained by dividing by the ratio is determined to be 2 or more and 6 or less.
In the invention according to claim 2, the ratio of the loss elastic modulus and the storage elastic modulus at 30° C. after heat melting and before heat treatment at 50° C. or higher and 60° C. or lower is 0.7 or more and 1 2. The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein the density is 0.5 or less.
In the invention according to claim 3, the binder polyester resin containing the crystalline polyester resin and the amorphous polyester resin is heated and melted, and with the lapse of cooling time, the crystalline polyester resin and the 2. The method of producing a toner for developing an electrostatic charge image according to claim 1, wherein phase separation from the amorphous polyester resin occurs.
The invention according to claim 4 is characterized in that the dispersion liquid is a dispersion liquid in which the crystalline polyester resin, the amorphous polyester resin, and a crystal nucleating agent are dispersed. 2. A method for producing a toner for developing an electrostatic image according to any one of 1. to 1. to 1.2.

According to the invention of claim 1, the ratio of the loss elastic modulus to the storage elastic modulus of the toner for electrostatic image development at 30° C. after heat melting and before heat treatment at 50° C. or higher and 60° C. or lower is A value obtained by dividing the ratio of the loss elastic modulus to the storage elastic modulus of the toner for electrostatic image development at 30° C. after being heat-melted and heat-treated at 50° C. or more and 60° C. or less is smaller than 2. Alternatively, compared to the case where the mixing ratio of the crystalline polyester resin and the amorphous polyester resin is determined to be greater than 6, it is possible to provide a toner for electrostatic charge image development in which the image formed on the recording medium is less likely to be chipped.
According to the invention of claim 2, the ratio of the loss elastic modulus to the storage elastic modulus of the toner for electrostatic image development at 30° C. after heat melting and before heat treatment at 50° C. or higher and 60° C. or lower is 0. The image formed on the recording medium can be less likely to be chipped compared to the case where it is smaller than 0.7 or larger than 1.5.
According to the invention of claim 3, the toner for electrostatic charge image development after being heated and fused can be changed from a more viscous state to a more elastic state.
According to the fourth aspect of the invention, the crystallinity of the toner for developing an electrostatic charge image is higher than in the case where the dispersion is not a dispersion in which a crystalline polyester resin, an amorphous polyester resin, and a crystal nucleating agent are dispersed. The ratio of the loss elastic modulus to the storage elastic modulus of the toner for electrostatic image development at 30° C. after heat melting and before heat treatment at 50° C. or higher and 60° C. or lower without reducing the content of the polyester resin. is divided by the ratio of the loss elastic modulus to the storage elastic modulus of the toner for electrostatic image development at 30° C. after heat-melting and heat treatment at 50° C. or higher and 60° C. or lower, is 2 or more. 6 or less.

1 is a diagram showing an example of the configuration of an image forming system; FIG.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below. In addition, this invention is not limited to the following embodiment. Further, various modifications can be made within the scope of the gist of the invention. Furthermore, the drawings used are for explaining the present embodiment and do not represent the actual size.

<Overall Configuration of Image Forming System 500>
FIG. 1 is a diagram showing the configuration of an image forming system 500 to which this embodiment is applied.
An image forming system 500 shown in FIG. A post-processing device 2 is provided for performing post-processing such as binding.

The image forming apparatus 1 is provided with four image forming units 100Y, 100M, 100C, and 100K (also collectively referred to as "image forming units 100") that form images based on respective color image data.
Each image forming unit 100 is provided with a photoreceptor drum 107 as an example of an image carrier and a charging roll 108 as an example of charging means for charging the photoreceptor drum 107 . Further, each image forming unit 100 includes an exposure device 101 as an example of exposure means for exposing the photosensitive drum 107 charged by the charging roll 108 , and an electrostatic charge formed on the photosensitive drum 107 by the exposure device 101 . A developing device 109 for developing the latent image is provided.

The image forming apparatus 1 is also provided with an intermediate transfer belt 102 onto which toner images for electrostatic charge image development (hereinafter referred to as toner) of respective colors formed by the image forming units 100 are transferred in multiple layers. The image forming apparatus 1 also includes a primary transfer roll 103 for sequentially transferring (primary transfer) the respective color toner images formed by the respective image forming units 100 onto the intermediate transfer belt 102 , and each color toner image transferred onto the intermediate transfer belt 102 . A secondary transfer roll 104 that collectively transfers (secondary transfer) the toner images onto the paper P, and a fixing device 105 as an example of fixing means that fixes the secondarily transferred toner images of each color onto the paper P are provided. Note that the intermediate transfer belt 102, the primary transfer roll 103, and the secondary transfer roll 104 can be regarded as transfer means for transferring the image formed on the photosensitive drum 107 onto the paper P. FIG.
Further, the image forming apparatus 1 is provided with a toner cartridge 120 containing toner to be supplied to the developing device 109 of each image forming unit 100 . Further, the image forming apparatus 1 is provided with a main control unit 106 configured by a program-controlled CPU and controlling the operation of the image forming apparatus 1 .

In each image forming unit 100 of the image forming apparatus 1, the process of charging the photosensitive drum 107, the process of forming an electrostatic latent image on the photosensitive drum 107 by scanning exposure from the exposing device 101, and the formed electrostatic latent image. A toner image of each color is formed through the developing process of each color toner.
Each color toner image formed on each image forming unit 100 is sequentially electrostatically transferred (primary transfer) onto an intermediate transfer belt 102 by a primary transfer roll 103 . Then, each color toner image is conveyed to the installation position of the secondary transfer roll 104 as the intermediate transfer belt 102 moves.

On the other hand, in the image forming apparatus 1, a plurality of sheets P of different sizes and different sheet types are stored in the sheet storage sections 110A to 110D.
When forming an image on the paper P, for example, the pickup roll 111 picks up the paper P from the paper container 110A, and the transport roller 112 transports the paper one by one to the position of the registration roller 113 .

Then, the paper P is supplied from the registration roll 113 in synchronization with the timing at which each color toner image on the intermediate transfer belt 102 is conveyed to the position where the secondary transfer roll 104 is arranged.
As a result, the toner images of each color are collectively electrostatically transferred (secondary transfer) onto the paper P by the action of the transfer electric field formed by the secondary transfer roll 104 .

After that, the paper P on which each color toner image is secondarily transferred is separated from the intermediate transfer belt 102 and conveyed to the fixing device 105 . In the fixing device 105, each color toner image is fixed on the paper P by a fixing process using heat and pressure to form an image.
Then, the paper P on which the image is formed is discharged from the paper discharge section T of the image forming apparatus 1 by the transport roll 114 and supplied to the post-processing device 2 .
The post-processing device 2 is arranged on the downstream side of the paper discharge section T of the image forming apparatus 1, and performs post-processing such as folding and binding on the paper P on which an image has been formed. The paper P is discharged to the discharge tray 130 after being post-processed.

<Constitution of Toner>
Next, the configuration of toner will be described.
The toner contains a binder resin made of a heat-meltable resin, a colorant, and a release agent.
The toner used in this embodiment is a viscoelastic body having viscoelasticity after being melted by heating.

(Binder resin)
A binding resin is a resin for binding toner to paper. More specifically, the binder resin is a resin that binds the heat-melted toner to the paper by adhering to the paper during the fixing process.
The binder resin used in the present embodiment is not particularly limited, but vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, and polyether resins, and non-vinyl resins such as modified rosin. resins, mixtures of vinyl-based resins and non-vinyl-based resins, or graft polymers obtained by polymerizing vinyl-based monomers in the presence of two or more of the above resins. Moreover, among these, it is preferable to use a polyester resin.
As the binder resin, one kind may be used alone, or two or more kinds may be used in combination.
Further, the binder resin contains a crystalline resin and an amorphous resin.

(Crystalline resin)
In this embodiment, the crystalline resin has a relatively steep endothermic peak in differential scanning calorimetry (DSC). More specifically, when the DSC measurement is performed at a heating rate of 10°C/min, the half width of the endothermic peak is within 10°C.
Crystalline resins have a large drop in viscosity at a specific temperature. When the toner contains a crystalline resin and an amorphous resin, the viscosity is reduced at a lower temperature than when the toner contains the amorphous resin but does not contain the crystalline resin, Fixability at low temperatures (low-temperature fixability) is improved.

On the other hand, the crystalline resin contributes to improving elasticity of the toner.
When the crystalline resin and amorphous resin contained in the toner are compatible with each other, the viscosity of the toner is high under heated conditions during fixing, but after fixing, the crystalline resin and non-crystalline resin become more viscous as the toner cools. Phase separation from the crystalline resin progresses, and the elasticity of the toner increases.

In this embodiment, a crystalline polyester resin can be suitably used as the crystalline resin. The crystalline polyester resin is preferably contained in an amount of 2 to 40 parts by mass, more preferably 2 to 20 parts by mass, per 100 parts by mass of the binder resin.

The crystalline polyester resin preferably has a melting temperature of 50° C. or higher and 100° C. or lower, more preferably 55° C. or higher and 90° C. or lower, and even more preferably 60° C. or higher and 85° C. or lower.
When the melting temperature of the crystalline polyester resin is 50° C. or higher, the toner on the paper having an image formed thereon is less likely to melt during storage.
When the melting temperature of the crystalline polyester resin is 100° C. or less, the low-temperature fixability of the toner is improved.
The melting temperature is obtained from the DSC curve obtained by DSC, based on the "melting peak temperature" described in "Determination of melting temperature" in JIS K 7121-1987 "Method for measuring transition temperature of plastics".
The crystalline polyester resin preferably has a weight average molecular weight (Mw) of 6000 or more and 35000 or less.

The crystalline polyester resin used in the present embodiment is not particularly limited, but a polycondensate produced by polycondensing a polyhydric carboxylic acid and a polyhydric alcohol can be suitably used. As the crystalline polyester resin, a commercially available product or a synthesized product may be used.
In the present embodiment, as the crystalline polyester resin, a polycondensate produced using a polymerizable monomer containing a linear aliphatic compound rather than a polymerizable monomer containing an aromatic compound is used. is preferred. A polycondensate produced using a polymerizable monomer containing a linear aliphatic compound tends to form a crystal structure.

The polycarboxylic acid used in the present embodiment is not particularly limited, but aliphatic dicarboxylic acids (oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9 -nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (phthalic acid, isophthalic acid, dibasic acids such as terephthalic acid and naphthalene-2,6-dicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (eg, having 1 to 5 carbon atoms).

As the polyvalent carboxylic acid, a tricarboxylic or higher carboxylic acid having a crosslinked structure or a branched structure may be used together with the dicarboxylic acid. Examples of tricarboxylic or higher carboxylic acids include aromatic carboxylic acids (1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, etc.) and their anhydrides. , or lower alkyl esters thereof (for example, having 1 to 5 carbon atoms). Furthermore, as the polyvalent carboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used together with the dicarboxylic acid.
As the polycarboxylic acid, one kind may be used alone, or two or more kinds may be used in combination.

Polyhydric alcohols used in the present embodiment include, but are not limited to, aliphatic diols (straight-chain diols having a main chain portion having 7 or more and 20 or less carbon atoms). Aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol and 1,8-octanediol. , 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol , 1,14-eicosandecanediol and the like. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferably used.

As the polyhydric alcohol, a trihydric or higher alcohol having a crosslinked structure or a branched structure may be used together with the diol. Trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol.
As the polyhydric alcohol, one kind may be used alone, or two or more kinds may be used in combination. When two or more kinds of polyhydric alcohols are used in combination, the ratio of the amount of the aliphatic diol to all the polyhydric alcohols is preferably 80% or more, more preferably 90% or more.

(amorphous resin)
An amorphous resin is a resin having a relatively gentle endothermic peak in DSC. More specifically, an amorphous resin is a resin whose endothermic peak half-value width exceeds 10° C. when DSC is performed at a heating rate of 10° C./min.
In this embodiment, an amorphous polyester resin can be suitably used as the amorphous resin.

The amorphous polyester resin preferably has a glass transition temperature (Tg) of 50° C. or higher and 80° C. or lower, more preferably 50° C. or higher and 65° C. or lower.
The glass transition temperature is obtained by converting the DSC curve obtained by DSC into the "extrapolated glass transition start temperature" described in JIS K 7121-1987 "Method for measuring the transition temperature of plastics", "How to determine the glass transition temperature". required based on

The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, more preferably 7,000 to 500,000.
The amorphous polyester resin preferably has a number average molecular weight (Mn) of 2,000 or more and 100,000 or less.
The amorphous polyester resin preferably has a molecular weight distribution (Mw/Mn) of 1.5 to 100, more preferably 2 to 60.

In addition, a weight average molecular weight and a number average molecular weight are measured by a gel permeation chromatography (GPC:Gel Permeation Chromatography). HLC (registered trademark)-8120GPC and TSKgel (registered trademark) SuperHM-M (15 cm) manufactured by Tosoh Corporation are used as measuring devices, and molecular weight is measured by GPC in THF solvent. From these measurement results, a weight average molecular weight and a number average molecular weight are calculated using a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample.

The amorphous polyester resin used in the present embodiment is not particularly limited, but a polycondensate produced by polycondensing a polyhydric carboxylic acid and a polyhydric alcohol can be used.
A commercially available product or a synthesized product may be used as the amorphous polyester resin.

The polyvalent carboxylic acid used in the present embodiment is not particularly limited, but aliphatic dicarboxylic acids (oxalic acid, malonic acid, maleic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid , adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides or their lower ( Examples thereof include alkyl esters having 1 to 5 carbon atoms. Among these, it is preferable to use an aromatic dicarboxylic acid.

As the polyvalent carboxylic acid, a tricarboxylic or higher carboxylic acid having a crosslinked structure or a branched structure may be used together with the dicarboxylic acid. Trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (for example, having 1 to 5 carbon atoms).
As the polycarboxylic acid, one kind may be used alone, or two or more kinds may be used in combination.

Polyhydric alcohols used in the present embodiment are not particularly limited, but aliphatic diols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic formula diols (cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), aromatic diols (ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred, and aromatic diols are more preferred.

As the polyhydric alcohol, a trihydric or higher alcohol having a crosslinked structure or a branched structure may be used together with the diol. Trihydric or higher alcohols include glycerin, trimethylolpropane, pentaerythritol and the like.
As the polyhydric alcohol, one kind may be used alone, or two or more kinds may be used in combination.

(Crystal nucleating agent)
The toner may contain a crystal nucleating agent.
The crystal nucleating agent promotes phase separation between the crystalline resin and the amorphous resin by bonding with the crystalline resin. As the distance between the nucleating agent and the crystalline resin becomes closer, phase separation between the crystalline resin and the amorphous resin is promoted.
The crystal nucleating agent used in the present embodiment is not particularly limited, but metal benzoate (sodium benzoate, etc.), metal stearate (sodium stearate, etc.), metal phosphate (sodium bis(4- tert-butylphenyl)phosphate, etc.), oxalic acid metal salts (calcium oxalate, etc.), sorbitol compounds (dibenzylidene sorbitol, etc.), carbon black, metal oxides (silica, etc.), kaolin, talc, and the like. Among these, it is more preferable to use a metal salt compound.

(coloring agent)
Pigments or dyes can be used as colorants.
Pigments used in the present embodiment are not particularly limited, but carbon black, chrome yellow, Hansa yellow, benzidine yellow, thren yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, Permanent Red, Brilliant Carmine 3B, Brilliant Carmine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine blue, pigment blue, phthalocyanine green, malachite green oxalate, and the like.
Dyes used in the present embodiment include acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, Polymethine-based, triphenylmethane-based, diphenylmethane-based, thiazole-based, and the like.

As the coloring agent, a surface-treated coloring agent may be used, or a dispersing agent may be used in combination.
The colorant is preferably contained in an amount of 1 to 30 parts by mass, more preferably 3 to 15 parts by mass, based on 100 parts by mass of the toner.

(Release agent)
The release agent used in the present embodiment is not particularly limited, but hydrocarbon waxes, natural waxes (carnauba wax, rice wax, candelilla wax, etc.), synthetic or mineral/petroleum waxes (montan wax, etc.), Examples include ester waxes.

The release agent preferably has a melting temperature of 50° C. or higher and 110° C. or lower, more preferably 60° C. or higher and 100° C. or lower.
The melting temperature is obtained from the DSC curve obtained by DSC, based on the "melting peak temperature" described in "Determination of melting temperature" in JIS K 7121-1987 "Method for measuring transition temperature of plastics".
The release agent is preferably contained in an amount of 1 to 20 parts by mass, more preferably 5 to 15 parts by mass, based on 100 parts by mass of the toner.

<Characteristics of Toner>
The toner used in this embodiment changes its viscoelasticity after being heated and melted. Specifically, immediately after the toner is melted by heating, the crystalline resin and the amorphous resin contained in the toner are compatible with each other. In this state, the viscosity of the toner is high, but the temperature of the toner decreases after that. As the phase separation between the crystalline resin and the amorphous resin progresses, the elasticity of the toner becomes stronger.
After the toner is heated and melted, the phase separation between the crystalline resin and the amorphous resin progresses within a range that does not excessively slow down and does not excessively accelerate the viscosity and elasticity of the toner. It is preferable to change within a speed range that does not increase.

If the progress of phase separation between the crystalline resin and the amorphous resin is excessively slow after the toner is heated and melted, the change in elasticity of the toner becomes excessively slow, and the elasticity of the toner does not become strong even after the toner is heated and melted. It may remain highly viscous. If the toner is highly viscous, it tends to transfer to anything it comes into contact with.
Therefore, for example, even if one paper P is subjected to fixing processing in the image forming apparatus 1 (see FIG. 1) and the one paper P is discharged to the discharge tray 130, the viscosity of the toner on this one paper P is high. There is a possibility that the toner on one sheet P may transfer to another sheet P stacked on top of the one sheet P.

If the phase separation between the crystalline resin and the amorphous resin progresses too fast after the toner is heated and melted, the change in elasticity of the toner becomes too fast, and the elasticity of the toner becomes stronger immediately after heating and melting. There is If the elasticity of the toner becomes too strong, the brittleness of the toner may also become strong.
Therefore, for example, after fixing processing is performed on the paper P in the image forming apparatus 1 (see FIG. 1), when the paper P is folded as a post-processing by the post-processing device 2, the image is formed on the folded portion of the paper P. image may be lost. More specifically, when a bending stress is applied to the paper P, the image formed on the paper P is bent together with the paper P. However, if the toner is highly brittle, the image may not be completely bent and chipped.

Further, when the toner is subjected to heat treatment at a temperature of 50° C. or more and 60° C. or less after heating and melting, the viscosity and elasticity of the toner after the heat treatment are neither too slow nor too fast after the heat treatment. It is preferable to change quickly in the range of height.
The temperature of 50° C. or more and 60° C. or less is, for example, after the fixing process of the paper P in the image forming apparatus 1 (see FIG. 1), when the paper P is post-processed by the post-processing device 2, or after the post-processing. It is the temperature in the environment where the paper P exists when the paper P is transported to the discharge tray 130 . Under this temperature environment, the viscosity and elasticity of the toner change within a speed range that does not become excessively slow or excessively fast. The lack of the image on the paper P after the paper P is discharged to 130 is suppressed.

Further, when the toner is heat-treated at a temperature of 50° C. or more and 60° C. or less after heat-melting, the value obtained by dividing the loss factor tan δ1 after heat-melting and before heat treatment by the loss factor tan δ2 after heat treatment (tan δ1/tan δ2). is preferably 2 or more and 6 or less, more preferably 2.2 or more and 5.1 or less, and even more preferably 3 or more and 5 or less.

Here, the loss coefficient tan δ is an index representing the viscoelasticity of the toner, and is a value obtained by dividing the loss elastic modulus of the toner by the storage elastic modulus (ratio between the loss elastic modulus and the storage elastic modulus). The higher the loss factor tan δ, the higher the viscosity of the toner. Also, the larger the value (tan δ1/tan δ2) obtained by dividing the loss factor tan δ1 before heat treatment by the loss factor tan δ2 after heat treatment, the faster the toner changes from a more viscous state to a more elastic state.
Hereinafter, a value obtained by dividing the loss factor tan δ1 of the toner after heat melting and before heat treatment by the loss factor tan δ2 of the toner after heat treatment is referred to as a loss factor ratio (tan δ1/tan δ2).

If the loss factor ratio (tan δ1/tan δ2) is less than 2 when heat treatment is performed at a temperature of 50° C. or higher and 60° C. or lower after the toner is heated and melted, the rate of change in elasticity of the toner after being heated and melted is excessively small. Become. In this case, even after heating and melting, the toner tends to remain highly viscous without increasing its elasticity. Therefore, the above-described toner transfer is more likely to occur.
If the loss factor ratio (tan δ1/tan δ2) is greater than 6 when heat treatment is performed at a temperature of 50° C. or higher and 60° C. or lower after the toner is heated and melted, the rate of change in elasticity of the toner after heating and melting is excessively large. Become. In this case, immediately after heating and melting, the elasticity of the toner increases and the brittleness of the toner tends to increase. Therefore, image defects are likely to occur.

Further, the loss factor tan δ1 of the toner before the heat treatment is preferably 0.7 or more and 1.5 or less, more preferably 0.8 or more and 1.1 or less.
If the loss factor tan δ1 of the toner before the heat treatment is less than 0.7, the elasticity of the toner is strong even before the heat treatment, and the elasticity of the toner is further enhanced after the heat treatment, and the toner tends to be brittle.
If the toner loss coefficient tan δ1 before the heat treatment is larger than 1.5, the viscosity of the toner before the heat treatment is excessively high, and the toner tends to remain highly viscous even after the heat treatment.
When the loss coefficient tan δ1 of the toner before the heat treatment is 0.8 or more and 1.1 or less, the above-described toner transfer and image chipping are less likely to occur after the toner is heated and melted.

In addition, the mixing ratio of the crystalline resin and the amorphous resin contained in the toner is such that the viscosity and elasticity of the toner after being heated and melted change within a speed range that does not excessively increase or decrease. is preferably defined. In other words, the mixing ratio of the crystalline resin and the amorphous resin contained in the toner is preferably determined so that the loss factor ratio (tan δ1/tan δ2) is 2 or more and 6 or less.

When the content of the crystalline resin in the toner is excessively low, the phase separation between the crystalline resin and the amorphous resin becomes difficult after the toner is heated and melted, and the loss factor ratio (tan δ1/tan δ2) becomes less than 2. also tend to be smaller. In addition, the above-described low-temperature fixability tends to deteriorate.
When the content of the crystalline resin is excessively high, the progress of phase separation between the crystalline resin and the amorphous resin becomes excessively fast after the toner is heated and melted, and the loss factor ratio (tan δ1/tan δ2) becomes higher than 6. easy to grow.

Further, when a toner is produced using a crystal nucleating agent, a dispersion (hereinafter referred to as a mixed dispersion) in which a crystalline resin, an amorphous resin, and a crystal nucleating agent are dispersed in one solution is prepared. is preferably used to manufacture toners.

When a toner is produced using a crystal nucleating agent separately from a dispersion liquid in which a crystalline resin is dispersed, the crystalline resin, the amorphous resin, and the crystal nucleating agent tend to be unevenly distributed in the toner. In this case, phase separation between the crystalline resin and the amorphous resin is less likely to proceed after the toner is heated and melted. Therefore, even if the contents of the crystal nucleating agent and the crystalline resin in the toner are increased, the loss factor ratio (tan δ1/tan δ2) of the toner may not become larger than 2 in some cases.
When a crystal nucleating agent bonded to a crystalline resin is used, the phase separation between the crystalline resin and the amorphous resin is remarkably accelerated, and the toner loss factor ratio (tan δ1/tan δ2) tends to be greater than 6.

When a toner is produced using a mixed dispersion, the crystalline resin, the amorphous resin and the crystal nucleating agent are present in positions that are neither too close nor too far from each other in the toner. In this case, although the phase separation between the crystalline resin and the amorphous resin progresses, the phase separation progresses more slowly than when the crystal nucleating agent is not used. Therefore, when a toner is produced using a mixed dispersion, the loss factor ratio (tan δ1/tan δ2) is less likely to exceed 6 even if the content of the crystalline resin in the toner is increased.
In this case, the low-temperature fixability of the toner is improved, and the viscosity and elasticity of the toner after heating and melting change within a speed range that does not excessively increase or decrease.

When the binder resin contains a crystalline polyester resin and an amorphous polyester resin, the absolute value of the difference between the SP value of the crystalline polyester resin and the SP value of the amorphous polyester resin is 0.5. It is preferable that it is more than or equal to 1.0 or less.
Here, the SP value is an index representing the solubility between the crystalline polyester resin and the amorphous polyester resin. The SP value is defined by the following formula (1).

In formula (1), ΔE represents the cohesive energy (cal/mol), V represents the molar volume (cm ³ /mol), and Δei represents the vaporization energy of the i-th atom or atomic group (cal/atom or atomic group ), Δvi represents the molar volume (cm ³ /atom or atomic group) of the i-th atom or atomic group, and i represents an integer of 1 or more.

When the absolute value of the difference between the SP value of the crystalline polyester resin and the SP value of the amorphous polyester resin is 0.5 or more, the toner on the paper having the image formed thereon is less likely to melt during storage.
When the absolute value of the difference between the SP value of the crystalline polyester resin and the SP value of the amorphous polyester resin is 1.0 or less, the low temperature fixability of the toner is improved.

<Toner manufacturing method>
Next, a method for manufacturing toner will be described.
First, a mixed resin particle dispersion in which crystalline resin particles, amorphous resin particles, and crystal nucleating agent particles are dispersed, a colorant particle dispersion in which colorant particles are dispersed, and a release agent in which release agent particles are dispersed A particle dispersion is prepared (dispersion preparation step).

Next, the mixed resin particle dispersion, the colorant particle dispersion, and the release agent particle dispersion are mixed to prepare a toner raw material liquid.
Subsequently, in the toner raw material liquid, the crystalline resin particles, the amorphous resin particles, the crystal nucleating agent particles, the colorant particles, and the releasing agent particles are hetero-aggregated to obtain the crystalline resin particles and the non-crystalline resin particles. Aggregated particles containing crystalline resin particles, crystal nucleating agent particles, colorant particles, and release agent particles are formed (aggregating step).
Specifically, the particles dispersed in the toner raw material liquid are aggregated by adding a flocculant to the toner raw material liquid, adjusting the pH of the mixed liquid to be acidic, and heating to the glass transition temperature of the resin particles. form particles.

Next, the solution in which the aggregated particles are formed is heated to a temperature equal to or higher than the glass transition temperature of the resin particles, thereby fusing the aggregated particles to form toner particles (forming step).
Through the steps described above, a toner in which the crystalline resin, the amorphous resin, and the crystal core material are dispersed is obtained. According to this toner, the loss factor ratio (tan δ1/tan δ2) of the toner becomes 2 or more and 6 or less when the heat treatment is performed at 50° C. or more and 60° C. or less. Therefore, when heat treatment is performed at a temperature of 50° C. or higher and 60° C. or lower after the toner is heated and melted, the change speed of the viscoelasticity of the toner is set to a speed range that does not cause an excessively viscous state or a brittle state. defined in

The present invention will be described in more detail below using examples. The present invention is not limited by these examples unless the gist thereof is exceeded.

A toner was produced and evaluated. The implementation conditions and evaluation results are shown in Table 1 below.
[Preparation of amorphous polyester resin]
First, the following monomers were prepared in order to prepare an amorphous polyester resin.
・Bisphenol A ethylene oxide 2.2 mol adduct: 230 parts by mass ・Bisphenol A propylene oxide 2.2 mol adduct: 367 parts by mass ・Dimethyl terephthalate: 163 parts by mass ・Dimethyl fumarate: 12 parts by mass ・Dodecenyl succinic anhydride Material: 227 parts by mass Trimellitic anhydride: 20 parts by mass

Next, bisphenol A ethylene oxide 2.2 mol adduct, bisphenol A propylene oxide 2.2 mol adduct, dimethyl terephthalate, and dodecenyl succinic anhydride were charged into a container, and 2.55 parts by mass of tin dioctoate was added. put in. Subsequently, under a nitrogen gas stream, the charged sample was reacted at 235° C. for 6 hours, then dimethyl fumarate and trimellitic anhydride were charged and reacted at 200° C. for 1 hour. Furthermore, the temperature was raised to 220° C. over 5 hours, and the monomer was polymerized under a pressure of 10 kPa to obtain a transparent pale yellow amorphous polyester resin.
The prepared amorphous polyester resin had a weight average molecular weight (Mw) of 35,000, a number average molecular weight (Mn) of 8,000, and a glass transition temperature (Tg) of 59°C.

[Preparation of crystalline polyester resin]
First, the following monomers were prepared in order to prepare a crystalline polyester resin.
・1,10-dodecanedioic acid: 225 parts by mass ・1,6-Hexanediol: 118 parts by mass

Next, the above two monomers were charged into a container, the air in the container was replaced with dry nitrogen gas, and then 0.86 parts by mass of titanium tetrabutoxide was charged. Subsequently, the mixture was stirred at 170° C. for 3 hours under a nitrogen gas stream. Further, the temperature was raised to 210° C. over 1 hour, the pressure in the container was reduced to 3 kPa, and the mixture was stirred for 13 hours to obtain a crystalline polyester resin.
The prepared crystalline polyester resin had a weight average molecular weight (Mw) of 25,000, a number average molecular weight (Mn) of 10,500, an acid value of 10.1 mgKOH/g, and a melting temperature calculated by DSC of 73.6°C. .

[Preparation of Mixed Resin Particle Dispersion (1)]
First, 75 parts by mass of the amorphous polyester resin, 25 parts by mass of the crystalline polyester resin, and 5 parts by mass of "NA-05" manufactured by ADEKA Co., Ltd. Cavitron CD1010 was dispersed using a disperser improved to a high temperature and high pressure type.

Next, ion-exchanged water is added until the mass percent concentration of the sample placed in the disperser becomes 1/5, the pH is adjusted to 8.5 using ammonia, the rotor rotation speed is 60 Hz, and the pressure is The disperser was operated under conditions of 5 kg/cm ² and 140° C. to prepare a mixed liquid of a crystalline polyester resin, an amorphous polyester resin, and a crystal nucleus material.
The volume average particle diameter of the resin particles in the prepared mixed liquid was 130 nm. Ion-exchanged water was added to this mixture to obtain a mixed resin particle dispersion (1) adjusted to have a solid content of 20%.

[Preparation of Mixed Resin Particle Dispersion (2)]
By the same method as the mixed resin particle dispersion liquid (1) except that the amorphous polyester resin was 85 parts by mass, the crystalline polyester resin was 15 parts by mass, and NA-05 was 2.4 parts by mass, A mixed resin particle dispersion (2) was prepared.

[Preparation of Mixed Resin Particle Dispersion (3)]
By the same method as the mixed resin particle dispersion (1) except that the amorphous polyester resin was 80 parts by mass, the crystalline polyester resin was 20 parts by mass, and NA-05 was 2.2 parts by mass, A mixed resin particle dispersion (3) was prepared.

[Preparation of Mixed Resin Particle Dispersion (4)]
By the same method as the mixed resin particle dispersion liquid (1) except that the amorphous polyester resin was 75 parts by mass, the crystalline polyester resin was 25 parts by mass, and NA-05 was 5.5 parts by mass, A mixed resin particle dispersion (4) was prepared.

[Preparation of amorphous polyester resin particle dispersion]
An amorphous polyester resin particle dispersion was prepared in the same manner as the mixed resin particle dispersion (1), except that the amorphous polyester resin was 100 parts by mass and the crystalline polyester resin and NA-05 were not used. was prepared.

[Preparation of crystalline polyester resin particle dispersion]
A crystalline polyester resin particle dispersion was prepared in the same manner as the mixed resin particle dispersion (1) except that the crystalline polyester resin was 100 parts by mass and the amorphous polyester resin and NA-05 were not used. prepared.

[Preparation of black pigment dispersion]
First, the following samples were prepared in order to prepare a black pigment dispersion.
・ Carbon black (Regal 330 manufactured by Cabot Corporation): 250 parts by mass ・ Anionic surfactant (Neogen (registered trademark) SC manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 33 parts by mass ・ Ion-exchanged water: 750 parts by mass

Next, 280 parts by mass of ion-exchanged water and 33 parts by mass of an anionic surfactant were put into the container. After dissolving the surfactant, 250 parts by mass of Regal 330 was added, and the mixture was stirred with a stirrer until the unwetted pigment disappeared and defoamed. After defoaming, the remaining ion-exchanged water is added, and a homogenizer (Ultra Turrax (registered trademark) T50 manufactured by IKA Japan Co., Ltd.) is used to stir for 10 minutes at 5000 rpm to disperse Regal 330. The mixture was stirred and defoamed for days. After defoaming, the mixture was again stirred at 6000 rpm for 10 minutes using the Ultra Turrax T50 to disperse Regal 330, and then stirred for 1 day with a stirrer to defoam.

Subsequently, Regal 330 was dispersed at a pressure of 240 MPa using a high-pressure impact type disperser Ultimizer (HJP30006 manufactured by Sugino Machine Co., Ltd.) to obtain a mixed liquid. The resulting mixture was allowed to stand for 72 hours to remove precipitates, and ion-exchanged water was added to obtain a black pigment dispersion adjusted to a solid content concentration of 15%.
The volume average particle size of the particles in the obtained black pigment dispersion was 135 nm.

[Preparation of Release Agent Dispersion]
First, the following samples were prepared in order to prepare a release agent dispersion.
· Polyethylene wax (Polywax (registered trademark) 725 manufactured by Baker Petrolite): 270 parts by mass · Anionic surfactant (Neogen RK manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 13.5 parts by mass · Ion exchange Water: 21.6 parts by mass

Next, the above three samples were mixed, the polywax was melted using a pressure discharge homogenizer (Golin Homogenizer manufactured by Gaulin Co.), the polywax was dispersed at a pressure of 5 MPa for 120 minutes, and then the pressure was 40 MPa. for 360 minutes to obtain a mixed liquid. The resulting mixture was cooled, and deionized water was added to obtain a release agent dispersion adjusted to a solid content concentration of 20.0%.
The volume-average particle size of the particles in the obtained release agent dispersion was 225 nm.

[Preparation of Toner]
(Example 1)
The following samples were prepared in order to produce the toner of this example.
・Mixed resin particle dispersion (1): 811 parts by mass ・Amorphous polyester resin particle dispersion: 349 parts by mass ・Crystalline polyester resin particle dispersion: 90 parts by mass ・Black pigment dispersion: 160 parts by mass ・Release Agent dispersion: 60 parts by mass Deionized water: 600 parts by mass Anionic surfactant (Dowfax (registered trademark) 2A1 manufactured by The Dow Chemical Company): 2.9 parts by mass

Next, all of the above samples are put into a container, and after adjusting the pH to 3.0 by adding nitric acid with a concentration of 1.0%, dispersion treatment is performed by stirring at a rotation speed of 3000 rpm using an Ultra Turrax T50. 100 parts by mass of an aluminum sulfate aqueous solution having a concentration of 2% was added while performing the above. After that, the rotating speed was increased to 5000 rpm and the mixture was stirred for 5 minutes.
Subsequently, after the temperature was raised to 40°C at a temperature increase rate of 0.2°C/min, the temperature was raised to 53°C at a temperature increase rate of 0.05°C/min to form the first aggregated particles, and 10 Particle size was measured by Multisizer 2 (manufactured by Beckman Coulter) every minute. When the volume average particle size of the first aggregated particles reached 5.0 μm, the temperature was maintained, and 70 parts by mass of the amorphous polyester resin particle dispersion liquid was added over 5 minutes.

Next, after holding the solution in the container at 50° C. for 30 minutes, 8 parts by mass of EDTA (ethylenediaminetetraacetic acid) having a concentration of 20% was added. Furthermore, a 1 mol/L sodium hydroxide aqueous solution was added to adjust the pH of the solution in the vessel to 9.0.
Subsequently, while maintaining the pH of the solution at 9.0, the temperature was raised to 90° C. at a heating rate of 1° C./min, and the particles were analyzed using an optical microscope and a field emission scanning electron microscope (FE-SEM). After confirming the coalescence, the solution in the container was cooled to 30° C. with cooling water.

Next, the cooled toner slurry was passed through a nylon mesh with an opening of 15 μm to remove coarse particles, and the toner slurry passed through the nylon mesh was filtered under reduced pressure using an aspirator. The solid content remaining on the filter paper was pulverized, put into ion-exchanged water at 30° C., stirred and mixed for 30 minutes, filtered again under reduced pressure using an aspirator, and the electrical conductivity of the filtrate was measured. This operation was repeated until the electric conductivity of the filtrate became 10 μS/cm or less to wash the solid content.
The washed solid content was pulverized with a wet dry granulator (Comil) and vacuum-dried in an oven at 35° C. for 36 hours to obtain toner particles. The toner particles had a volume average particle diameter of 6.0 μm.

Subsequently, 1.5 parts by mass of hydrophobic silica having a volume average particle diameter of 20 nm was added to 100 parts by mass of toner particles, and mixed for 3 minutes at a peripheral speed of 33 m/s using a mixer.
The toner of this example was produced by the above steps.

(Examples 2 to 10)
A toner was produced in the same manner as in Example 1, except that changes were made as shown in Table 1.

(Comparative Examples 1 to 3)
A toner was produced in the same manner as in Example 1, except that changes were made as shown in Table 1.
In other words, in Comparative Example 1, no crystalline polyester resin particle dispersion liquid was used in producing the toner.
In Comparative Examples 2 and 3, the mixed resin particle dispersion was not used in producing the toner.

[Method for measuring loss factor tan δ1 before heat treatment]
For the toners of Examples 1 to 10 and Comparative Examples 1 to 3, the loss factor tan δ1 before heat treatment was measured.
Specifically, first, the toner was melt-molded on a hot plate at 130°C into a cylindrical shape, and then cooled to 30°C. Next, using a rotating plate rheometer (RDA 2RHIOS system Ver.4.3.2 manufactured by Rheometric Scientific F.E. Co., Ltd.), a temperature increase rate of 1 ° C./min, a frequency of 1 rad/sec, The storage elastic modulus and the loss elastic modulus were measured based on the detected torque within the range of guaranteed measurement values with a strain of 20% or less. The loss factor tan δ1 before the heat treatment was calculated from the obtained measured values.

[Method for measuring loss factor tan δ2 after heat treatment]
For the toners of Examples 1 to 10 and Comparative Examples 1 to 3, the loss factor tan δ2 after heat treatment was measured.
Specifically, first, the toner was melt-molded on a hot plate at 130° C. into a cylindrical shape, then cooled to 50° C. and held for 2 hours. Next, the temperature of the hot plate was lowered to 30° C., and the storage modulus and loss modulus were measured by the same method as the method for measuring the loss factor tan δ1 before the heat treatment. A loss factor tan δ2 after the heat treatment was calculated from the measured values obtained.

As evaluations of the toners of Examples 1 to 10 and Comparative Examples 1 to 3, evaluation of low-temperature fixability, evaluation of folded image strength, evaluation of friction resistance, and evaluation of heat resistance were performed. All evaluations were made within 24 hours after the image was formed on the paper.

[Image formation on paper]
Using the toners of Examples 1 to 10 and Comparative Examples 1 to 3, images were formed on paper.
Specifically, toner was filled in a developing device in a modified machine of ApeosPort-V C7775 manufactured by Fuji Xerox Co., Ltd., and the loading amount of toner on paper was set to 1.0 mg/cm ² . Also, a solid image with an image density of 100% and a halftone image with an image density of 30% were formed on the leading edge and the trailing edge of the paper, and the temperature of the fixing device was set to 140° C. to perform fixing processing. .

As the paper, three types of Fuji Xerox Co., Ltd. Premier TCF (80 g/m ² ), OK Prince (104 g/m ² ), and OK Topcoat (104 g/m ² ) were used. Of these papers, Premier TCF has the roughest surface and OK Topcoat has the smoothest surface.
For each of the following evaluations, 1000 sheets of each of the above three types of paper were output under a low-temperature, low-humidity environment with a temperature of 15° C. and a humidity of 10% and a normal environment with a temperature of 25° C. and a humidity of 50%.

[Evaluation of Low Temperature Fixability]
Low temperature fixability was evaluated for the toners of Examples 1-10 and Comparative Examples 1-3.
Specifically, solid images formed on the leading edge and trailing edge of the paper were visually observed to evaluate the degree of defects in the image. In addition, the evaluation criteria are as follows. Among the following evaluation criteria, the evaluations of ⊚, ◯, and Δ were regarded as pass, and the evaluation of × was regarded as unacceptable.
◎: No image defects were observed ○: Slight image defects were observed, but there was no problem in use △: Slight image defects were observed ×: Image defects were observed As the paper has a larger basis weight and is thicker, the heat given to the image in the fixing process is more likely to disperse in the paper, so that the low-temperature fixability tends to deteriorate. Also, the rougher the surface of the paper, the more difficult it is for the heat to be uniformly transferred to the toner on the paper, so the low-temperature fixability tends to deteriorate.

[Evaluation of Folding Image Strength]
Fold image strength was evaluated for the toners of Examples 1-10 and Comparative Examples 1-3.
Specifically, the portion of the paper on which the solid image was formed was mountain-folded, and a pressure of 10 g/cm ² was applied to the mountain-folded paper for 1 minute. After that, the mountain fold was opened and the folded portion was wiped with a gauze, and the degree of image defects was evaluated. In addition, the evaluation criteria are as follows. Among the following evaluation criteria, the evaluations of ⊚, ◯, and Δ were regarded as pass, and the evaluation of × was regarded as unacceptable.
⊚: No image defects were observed. ◯: Very slight image defects were observed, but there was no problem in use. (wider than 500 μm) image defects were confirmed

In the image forming system 500 (see FIG. 1), when the sheet is folded by the post-processing device 2, the portion of the sheet on which the image is formed may be folded. Further, when the paper is conveyed after the folding process, a conveying roll (not shown) may pass through the portion of the paper on which the image is formed.
Therefore, the evaluation of image defects when the portion of the paper on which the image was formed was folded and then the folded portion was wiped with gauze was used as the evaluation of the strength of the image when the paper was folded and transported. .

〔Evaluation results〕
Table 2 shows the evaluation results of the low temperature fixability.
As shown in Table 2, the toners of Examples 1 to 10 all passed the evaluation under any environment and on any paper.
In addition, the toners of Comparative Examples 2 and 3 all passed the evaluation under any environment and on any paper.

On the other hand, with the toner of Comparative Example 1, defects were confirmed in the image formed on the paper with the OK topcoat under the low-temperature and low-humidity environment.
Concerning this, in Comparative Example 1, the low-temperature fixability was considered to be low because the crystalline polyester resin particle dispersion was not used in the preparation of the toner.

Table 3 shows the evaluation results of the bending image strength.
As shown in Table 3, the toners of Examples 1 to 10 all passed the evaluation under any environment and on any paper.
In addition, the toner of Comparative Example 1 passed the evaluation under any environment and on any paper.

On the other hand, with the toners of Comparative Examples 2 and 3, crack-like image defects (having a width of more than 500 μm) were observed on OK Prince paper under a low-temperature, low-humidity environment.
On the other hand, in Comparative Examples 2 and 3, the crystalline polyester resin particle dispersion was used in the preparation of the toner, but the mixed resin particle dispersion was not used. is also big. Therefore, it is considered that the elasticity of the toner became stronger and the brittleness became stronger, and the image on the paper received bending stress and cracked.

According to the results of Examples 1 to 10 and Comparative Examples 1 to 3, by setting the toner loss factor ratio (tan δ1/tan δ2) to 2 or more and 6 or less, the speed at which the viscoelasticity of the toner changes after heating and melting can be excessively reduced. It was confirmed that it is necessary to set the speed within a range that does not slow down and does not speed up excessively.

DESCRIPTION OF SYMBOLS 1... Image forming apparatus 2... Post-processing apparatus 120... Toner cartridge 500... Image processing system

Claims (4)

an aggregating step of aggregating the crystalline polyester resin and the amorphous polyester resin in a dispersion liquid in which the crystalline polyester resin and the amorphous polyester resin are dispersed to obtain aggregated particles;
The aggregated particles are heated and fused to obtain toner particles that are viscoelastic after being heated and melted and that change from a viscous state to a more elastic state when heat treatment is performed at 50° C. or more and 60° C. or less. a forming step of forming;
including
The mixing ratio of the crystalline polyester resin and the amorphous polyester resin in the aggregation step is the loss elastic modulus and storage elasticity at 30 ° C. after heat melting and before heat treatment at 50 ° C. or higher and 60 ° C. or lower. The value obtained by dividing the ratio of the elastic modulus to the elastic modulus by the ratio of the loss elastic modulus to the storage elastic modulus at 30° C. after heat melting and heat treatment at 50° C. or higher and 60° C. or lower is 2 or more and 6 or less. A method for producing a toner for developing an electrostatic charge image, characterized in that it is determined as follows. The ratio of the loss elastic modulus to the storage elastic modulus at 30° C. after heat melting and before heat treatment at 50° C. or higher and 60° C. or lower is 0.7 or higher and 1.5 or lower. 2. The method of producing a toner for developing an electrostatic charge image according to claim 1. In the binder polyester resin containing the crystalline polyester resin and the amorphous polyester resin, after heating and melting, the crystalline polyester resin and the amorphous polyester resin undergo phase separation with the lapse of cooling time. 2. The method of manufacturing a toner for developing an electrostatic charge image according to claim 1, wherein the toner is 4. The electrostatic image according to claim 1, wherein the dispersion is a dispersion in which the crystalline polyester resin, the amorphous polyester resin, and a crystal nucleating agent are dispersed. A method for manufacturing toner for development.

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