JP2019061033A - Toner for electrostatic charge image development, method for manufacturing toner for electrostatic charge image development, and image forming apparatus - Google Patents

Abstract

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 its viscoelasticity changes outside a predetermined speed range.SOLUTION: A toner for electrostatic charge image development contains a colorant and a binder resin formed of a resin that is fused upon heating, is a viscoelastic body after being heated and fused, and changes, with the lapse of time of cooling from a more sticky state to a more elastic state within a predetermined speed range. When heat treatment is performed, after the heating and fusion, on the toner for electrostatic charge image development within a predetermined temperature range, the speed of change in viscoelasticity becomes larger within the predetermined range after the heat treatment than that before the heat treatment.SELECTED DRAWING: Figure 1

Description

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

  Patent Document 1 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 above the softening point.

JP, 2004-163571, A

  In an image forming system, for example, a toner for developing an electrostatic charge image is placed on a recording medium, and the toner is fixed on the recording medium by heating and pressing the recording medium on which the toner is placed, and then the recording medium is discharged. There is. In addition, as the electrostatic charge image developing toner, a toner which is a visco-elastic body after being heated and melted may be used.

Here, after the toner is heated and melted by the fixing of the recording medium, the toner may change from a more viscous state to a more elastic state.
If the change rate of the viscoelasticity of the toner is excessively high, for example, the elasticity of the toner may become strong immediately after the heating and melting, and the brittleness of the toner may become strong. In this case, the external image acts on the image on the recording medium after fixing the recording medium and before discharging the image (for example, when the recording medium is bent by the post-processing apparatus) There is a possibility that the image located at the bent portion may be missing).

  In addition, if the change speed of the viscoelasticity of the toner is excessively low, for example, the recording medium may be discharged while the viscosity of the toner is high. In this case, the image on the ejected recording medium is transferred to another part (for example, the image on the ejected one recording medium is transferred to another recording medium to be ejected and stacked next). The image on the medium may be lost.

  An object of the present invention is to provide an electrostatic charge image developing toner in which the image formed on the recording medium is less likely to be chipped compared to when the viscoelasticity changes outside a predetermined speed range.

The invention according to claim 1 includes a binder resin made of a heat-melting resin, and a coloring agent, which is a visco-elastic body after heat-melting and is more viscous with the passage of time for cooling. It is a toner for developing an electrostatic charge image characterized by changing to a more elastic state in a predetermined speed range.
According to the second aspect of the present invention, when heat treatment is performed at a predetermined temperature range after heating and melting, the change rate of viscoelasticity is determined in advance after heat treatment rather than before heat treatment. The toner for developing an electrostatic charge image according to claim 1, characterized in that
The invention according to claim 3 is the toner for developing an electrostatic charge image according to claim 2, wherein the predetermined temperature range is 50 ° C. or more and 60 ° C. or less.
The invention according to claim 4 is that the value obtained by dividing the ratio of loss elastic modulus to storage elastic modulus before heat treatment by the ratio of loss elastic modulus to storage elastic modulus after heat treatment is 2 or more and 6 or less. 4. The toner for developing an electrostatic charge image according to claim 3, wherein
The invention according to claim 5 is characterized in that the ratio of the loss elastic modulus to the storage elastic modulus before heat treatment is 0.7 or more and 1.5 or less. Toner.
The invention according to claim 6 is the toner for electrostatic image development according to claim 1, wherein the binder resin contains a crystalline resin and an amorphous resin.
The invention according to claim 7 is characterized in that, in the binder resin, the crystalline resin and the non-crystalline resin are phase-separated as the cooling time elapses after the heating and melting. 6 is the toner for developing an electrostatic charge image according to Item 6.
The invention according to claim 8 is characterized in that the mixing ratio of the crystalline resin and the non-crystalline resin is determined such that the rate of change in viscoelasticity is in the range of the predetermined speed. The toner for electrostatic image development according to claim 7.
In the invention according to claim 9, the binder resin further includes a crystal nucleating agent which promotes phase separation between the crystalline resin and the amorphous resin by bonding with the crystalline resin,
9. The toner according to claim 8, wherein the crystalline resin, the amorphous resin, and the crystal nucleating agent are dispersed.
The invention according to claim 10 is the aggregation obtained by aggregating the crystalline resin particles and the non-crystalline resin particles in a dispersion liquid in which the crystalline resin particles and the non-crystalline resin particles are dispersed. In the step, the aggregated particles are heated and fused, and after heating and melting, the viscoelastic body is in a range of a predetermined speed from a more viscous state to a more elastic state with the passage of cooling time. Forming a toner particle which varies in the forming step, and a mixing ratio of the crystalline resin particle and the non-crystalline resin particle in the aggregation step is determined to be in the range of the speed. It is a method of producing a toner for developing an electrostatic charge image, which is characterized.
In the invention according to claim 11, a crystal nucleating agent which promotes phase separation between the crystalline resin particles and the non-crystalline resin particles by bonding with the crystalline resin is contained in the aggregated particles, 11. The method according to claim 10, wherein the crystalline resin particles, the amorphous resin particles, and the crystal nucleating agent are dispersed in the dispersion. is there.
The invention according to claim 12 comprises an image carrier, charging means for charging the surface of the image carrier, exposure means for exposing the charged image carrier to form an electrostatic charge image, and heating and melting. Electrostatic resin which is a visco-elastic body after heating and melting, and which changes from a more viscous state to a more elastic state within a predetermined speed range after heating and melting. A developing unit that contains an image developing toner and develops an electrostatic charge image formed on the surface of the image carrier; a transfer unit that transfers the image formed on the surface of the image carrier onto a recording medium; And a fixing unit configured to fix an image transferred to a medium.

According to the first aspect of the present invention, it is possible to provide a toner for electrostatic image development in which the image formed on the recording medium is less likely to be chipped than when the viscoelasticity changes outside a predetermined speed range.
According to the second aspect of the invention, it is possible to make the image formed on the recording medium subjected to the heat treatment less likely to be chipped compared to the case where the change rate of the viscoelasticity becomes larger before the heat treatment than after the heat treatment. .
According to the third aspect of the present invention, it is possible to make the image formed on the recording medium in a temperature environment of 50 ° C. or more and 60 ° C. or less difficult to chip.
According to the fourth aspect of the present invention, the viscoelasticity of the electrostatic image developing toner can be changed within a predetermined speed range.
According to the invention of claim 5, the image formed on the recording medium is chipped compared to the case where the ratio of loss modulus to storage modulus before heat treatment is smaller than 0.7 or larger than 1.5. It can be difficult.
According to the sixth aspect of the present invention, the toner can be fixed to the recording medium at a lower temperature than in the case where the crystalline resin is not contained in the binder resin.
According to the seventh aspect of the present invention, it is possible to change the electrostatic image developing toner after heating and melting from a more viscous state to a more elastic state.
According to the eighth aspect of the present invention, the viscoelasticity of the electrostatic image developing toner can be changed in a predetermined speed range.
According to the invention of claim 9, the content of the crystalline resin in the toner for electrostatic charge image development is not reduced as compared with the case where the crystalline resin, the amorphous resin and the crystal nucleating agent are not dispersed. In addition, the viscoelasticity of the electrostatic image developing toner can be changed within a predetermined speed range.
According to the tenth aspect of the present invention, it is possible to provide a toner for electrostatic image development in which the image formed on the recording medium is less likely to be chipped, as compared to the case where the viscoelasticity changes outside a predetermined speed range.
According to the invention of claim 11, the content of the crystalline resin in the toner for electrostatic charge image development is not reduced as compared with the case where the crystalline resin, the amorphous resin and the crystal nucleating agent are not dispersed. In addition, the viscoelasticity of the electrostatic image developing toner can be changed within a predetermined speed range.
According to the twelfth aspect of the present invention, it is possible to provide a toner for developing an electrostatic charge image in which the image formed on the recording medium is less likely to be chipped, as compared to the case where the viscoelasticity changes outside the predetermined speed range.

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

  Hereinafter, modes for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments. Moreover, it can variously deform and implement within the range of the summary. Further, the drawings used are for describing the present embodiment and do not represent actual sizes.

Overall Configuration of Image Forming System 500
FIG. 1 is a diagram showing the configuration of an image forming system 500 to which the present embodiment is applied.
An image forming system 500 shown in FIG. 1 includes an image forming apparatus 1 such as a printer or a copier that forms a color image on a sheet P as an example of a recording medium, and a sheet P on which an image is formed by the image forming apparatus 1. And a post-processing device 2 that performs 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") for forming an image based on each color image data.
Each image forming unit 100 is provided with a photosensitive drum 107 as an example of an image holder, and a charging roll 108 as an example of a charging unit that charges the photosensitive drum 107. In each of the image forming units 100, an exposure unit 101 as an example of an exposure unit that exposes the photosensitive drum 107 charged by the charging roller 108, and electrostatics formed on the photosensitive drum 107 by the exposure unit 101. A developing device 109 for developing the latent image is provided.

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

In each image forming unit 100 of the image forming apparatus 1, the step of charging the photosensitive drum 107, the step of forming an electrostatic latent image on the photosensitive drum 107 by scanning exposure from the exposure unit 101, the formed electrostatic latent image The toner image of each color is formed through the developing process of each color toner.
The respective color toner images formed in the respective image forming units 100 are electrostatically transferred (primary transfer) on the intermediate transfer belt 102 by the primary transfer roll 103. Then, with the movement of the intermediate transfer belt 102, each color toner image is conveyed to the installation position of the secondary transfer roll 104.

On the other hand, in the image forming apparatus 1, a plurality of sheets P of different sizes and different sheet types are accommodated in the sheet accommodating portions 110A to 110D.
Then, at the time of image formation on the sheet P, for example, the sheet P is taken out from the sheet storage section 110A by the pickup roll 111, and is conveyed by the conveyance roll 112 to the position of the registration roll 113 one by one.

Then, at the timing when each color toner image on the intermediate transfer belt 102 is conveyed to the arrangement position of the secondary transfer roll 104, the sheet P is supplied from the resist roll 113.
Thereby, the toner images of the respective colors are collectively electrostatically transferred (secondary transfer) onto the sheet P by the action of the transfer electric field formed by the secondary transfer roll 104.

Thereafter, the sheet P on which each color toner image has been secondarily transferred is separated from the intermediate transfer belt 102 and conveyed to the fixing device 105. In the fixing unit 105, each color toner image is fixed on the sheet P by the fixing process by heat and pressure, and an image is formed.
Then, the sheet P on which the image is formed is discharged from the sheet discharge unit T of the image forming apparatus 1 by the conveyance roll 114 and is supplied to the post-processing apparatus 2.
The post-processing apparatus 2 is disposed downstream of the sheet discharge unit T of the image forming apparatus 1, and performs post-processing such as folding and binding on the sheet P on which an image is formed. The sheet P is discharged to the discharge tray 130 after being subjected to post-processing.

<Structure of Toner>
Next, the configuration of the toner will be described.
The toner contains a binder resin made of a heat-melting resin, a colorant, and a release agent.
The toner used in the present embodiment is a visco-elastic material having visco-elasticity after being heated and melted.

(Binder resin)
The binder resin is a resin for binding toner to paper. More specifically, the binder resin is a resin that adheres to the sheet during the fixing process to bind the heat-melted toner to the sheet.
The binder resin used in the present embodiment is not particularly limited, but non-vinyl such as epoxy resin, polyester resin, polyurethane resin, polyamide resin, cellulose resin, vinyl resin such as polyether resin, modified rosin, etc. Examples thereof include a graft resin obtained by polymerizing a vinyl-based monomer in the coexistence of two or more resins among the above resins, or a mixture of a vinyl-based resin and a non-vinyl-based resin. Among these, it is preferable to use a polyester resin.
As the binder resin, one type may be used alone, or two or more types 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 temperature rising rate of 10 ° C./min, the half value width of the endothermic peak is within 10 ° C.
Crystalline resins have a large drop in viscosity at certain temperatures. When the toner contains a crystalline resin and an amorphous resin, the viscosity is lowered at a lower temperature than in the case where the amorphous resin is contained while the crystalline resin is not contained, Fixing performance (low temperature fixability) at low temperature is improved.

On the other hand, the crystalline resin contributes to the improvement of the elasticity of the toner.
When the crystalline resin and the amorphous resin contained in the toner are compatible with each other, the viscosity of the toner is strong under the heated condition at the time of fixing, but after fixing, the crystalline resin and the non-crystalline resin are not cooled. The phase separation with the crystalline resin proceeds, and the elasticity of the toner becomes strong.

  In the present embodiment, a crystalline polyester resin can be suitably used as the crystalline resin. The crystalline polyester resin preferably contains 2 parts by mass or more and 40 parts by mass or less, and more preferably 2 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the binder resin.

The crystalline polyester resin preferably has a melting temperature of 50 ° C. to 100 ° C., more preferably 55 ° C. to 90 ° C., and still more preferably 60 ° C. to 85 ° C.
When the melting temperature of the crystalline polyester resin is 50 ° C. or more, the toner on the paper is difficult to melt when the paper on which the image is formed is stored.
When the melting temperature of the crystalline polyester resin is 100 ° C. or less, the low temperature fixability of the toner is improved.
In addition, melting temperature is calculated | required based on the "melting peak temperature" as described in "the determination method of melting temperature" of JISK7121-1987 "the transition temperature measurement method of plastics" from the DSC curve obtained by DSC.
The crystalline polyester resin preferably has a weight average molecular weight (Mw) of 6,000 or more and 35,000 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. In addition, as a crystalline polyester resin, a commercial item may be used and you may use what was synthesize | combined.
In this embodiment, a polycondensate produced using a polymerizable monomer containing a linear aliphatic compound rather than a polymerizable monomer containing an aromatic compound is used as the crystalline polyester resin. Is preferred. In a polycondensate produced using a polymerizable monomer containing a linear aliphatic compound, a crystal structure is easily formed.

  The polyvalent carboxylic 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) Nonane dicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid etc., aromatic dicarboxylic acid (phthalic acid, isophthalic acid, etc.) Terephthalic acid, dibasic acids such as naphthalene-2, 6-dicarboxylic acid, etc., anhydrides thereof or lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms) can be mentioned.

As the polyvalent carboxylic acid, a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure may be used in combination with the dicarboxylic acid. Examples of trivalent 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 anhydrides thereof Or lower (eg, 1 to 5 carbon atoms) alkyl esters thereof, and the like. Furthermore, as the polyvalent carboxylic acid, together with a dicarboxylic acid, a dicarboxylic acid having a sulfonic acid group or a dicarboxylic acid having an ethylenic double bond may be used in combination.
As polyvalent carboxylic acid, one may be used alone, or two or more may be used in combination.

  The polyhydric alcohol used in the present embodiment is not particularly limited, but includes aliphatic diols (linear diols having 7 to 20 carbon atoms in the main chain portion). As aliphatic diols, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol , 1, 14-eicosan decanediol and the like. Among these, it is preferable to use 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol.

As a polyhydric alcohol, a trivalent or higher alcohol having a crosslinked structure or a branched structure may be used in combination with a diol. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol and the like.
One type of polyhydric alcohol may be used alone, or two or more types may be used in combination. When using 2 or more types together as polyhydric alcohol, it is preferable to make the ratio of the substance mass of aliphatic diol with respect to all the polyhydric alcohols into 80% or more, and it is more preferable to set it as 90% or more.

(Amorphous resin)
Amorphous resin is a resin having a relatively slow endothermic peak in DSC. More specifically, the amorphous resin is a resin in which the half value width of the endothermic peak exceeds 10 ° C. when DSC is performed at a temperature rising rate of 10 ° C./min.
In the present embodiment, an amorphous polyester resin can be suitably used as the amorphous resin.

The glass transition temperature (Tg) of the amorphous polyester resin is preferably 50 ° C. or more and 80 ° C. or less, and more preferably 50 ° C. or more and 65 ° C. or less.
Here, the glass transition temperature is the “extrapolated glass transition start temperature” described in “How to determine the glass transition temperature” in JIS K 7121-1987 “Method for measuring transition temperature of plastic” from the DSC curve obtained by DSC. It is determined on the basis of

The weight average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500000 or less.
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 or more and 100 or less, and more preferably 2 or more and 60 or less.

  The weight average molecular weight and the number average molecular weight are measured by gel permeation chromatography (GPC: Gel Permeation Chromatography). As a measuring device, HLC (registered trademark)-8120 GPC, TSKgel (registered trademark) SuperHM-M (15 cm) manufactured by Tosoh Corp. is used, and molecular weight measurement by GPC is performed in a THF solvent. From this measurement result, the weight average molecular weight and the number average molecular weight are calculated using the molecular weight calibration curve prepared by the monodispersed polystyrene standard sample.

The non-crystalline polyester resin used in the present embodiment is not particularly limited, but a polycondensate produced by polycondensing a polyvalent carboxylic acid and a polyvalent alcohol can be used.
A commercial item may be used as amorphous polyester resin, and what was synthesize | combined may be used.

  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, alkenyl succinic acid) , Adipic acid, sebacic acid etc.), alicyclic dicarboxylic acids (eg cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid etc.), their anhydrides or their lower For example, C1 or more and 5 or less) alkyl ester etc. are mentioned. Among these, aromatic dicarboxylic acids are preferably used.

As the polyvalent carboxylic acid, a trivalent or higher carboxylic acid having a crosslinked structure or a branched structure may be used in combination with the dicarboxylic acid. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower (eg, 1 to 5 carbon atoms) alkyl esters thereof.
As polyvalent carboxylic acid, one may be used alone, or two or more may be used in combination.

  The polyhydric alcohol used in the present embodiment is not particularly limited, but aliphatic diols (ethylene glycol, diethylene glycol, triethylene 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.) can be mentioned. Among these, aromatic diols and alicyclic diols are preferable, and aromatic diols are more preferable.

As a polyhydric alcohol, a trivalent or higher alcohol having a crosslinked structure or a branched structure may be used in combination with a diol. Examples of trihydric or higher alcohols include glycerin, trimethylolpropane and pentaerythritol.
One type of polyhydric alcohol may be used alone, or two or more types may be used in combination.

(Crystal nucleating agent)
The toner may contain a nucleating agent.
The nucleating agent promotes phase separation between the crystalline resin and the amorphous resin by bonding with the crystalline resin. As the distance between the crystal nucleating agent and the crystalline resin decreases, 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, and metal salts of benzoic acid (such as sodium benzoate), metal salts of stearic acid (such as sodium stearate), metal salts of phosphate (sodium bis (4- tert-Butylphenyl) phosphate etc., metal salts of oxalate (such as calcium oxalate), sorbitol compounds (such as dibenzylidene sorbitol), carbon black, metal oxides (such as silica), kaolin, talc and the like. Among these, it is more preferable to use a metal salt compound.

(Colorant)
As a coloring agent, a pigment or a dye can be used.
The pigment used in this embodiment is not particularly limited, and carbon black, chrome yellow, Hansa yellow, benzidine yellow, Sureren 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, Risol Red, Rhodamine B Lake, Lake Red C, Pigment Red, Rose Bengal, Aniline Blue, Ultramarine Blue, Chalco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, pigment blue, phthalocyanine green, malachite green oxalate and the like can be mentioned.
Dyes used in the present embodiment include acridine type, xanthene type, azo type, benzoquinone type, azine type, anthraquinone type, thioindico type, dioxazine type, thiazine type, azomethine type, indigo type, phthalocyanine type, aniline black type, Examples include polymethines, triphenylmethanes, diphenylmethanes, and thiazoles.

The colorant may be a surface-treated colorant, or may be used in combination with a dispersant.
The colorant is preferably contained in an amount of 1 to 30 parts by mass, and 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, and hydrocarbon wax, natural wax (carnauba wax, rice wax, candelilla wax, etc.), synthetic or mineral / petroleum wax (montan wax, etc.), An ester wax etc. are mentioned.

The melting temperature of the release agent is preferably 50 ° C. or more and 110 ° C. or less, and more preferably 60 ° C. or more and 100 ° C. or less.
In addition, melting temperature is calculated | required based on the "melting peak temperature" as described in "the determination method of melting temperature" of JISK7121-1987 "the transition temperature measurement method of plastics" from the DSC curve obtained by DSC.
The releasing agent is preferably contained in an amount of 1 to 20 parts by mass, and more preferably 5 to 15 parts by mass, based on 100 parts by mass of the toner.

<Characteristics of Toner>
The toner used in the present embodiment changes its viscoelasticity after being heated and melted. Specifically, immediately after the toner is heated and melted, the crystalline resin and the non-crystalline resin contained in the toner are compatible with each other. In this state, the viscosity of the toner is strong, but the temperature of the toner decreases thereafter. As the phase separation between the crystalline resin and the amorphous resin proceeds, the elasticity of the toner becomes stronger.
The toner does not excessively slow in viscosity and elasticity by excessively advancing the phase separation between the crystalline resin and the non-crystalline resin after heating and melting so that the phase separation does not occur too late and does not proceed excessively. It is preferable to change within a range of non-fast speeds.

If the progress of phase separation between crystalline resin and amorphous resin is too slow after the heating and melting of the toner, the change to the elasticity of the toner becomes too slow, and the elasticity of the toner does not become strong even after the heating and fusing. There may be cases where the viscosity is strong. When the viscosity of the toner is high, the toner tends to be transferred to the one that comes in contact.
Therefore, for example, even if the fixing process is performed on one sheet P in the image forming apparatus 1 (see FIG. 1) and the one sheet P is discharged to the discharge tray 130, the viscosity of the toner on the one sheet P is strong. The toner on one sheet P may be transferred to another sheet P stacked on one sheet P.

If the progress of phase separation between the crystalline resin and the amorphous resin is too fast after the heating and melting of the toner, the change to the elasticity of the toner becomes too fast and the elasticity of the toner becomes strong immediately after the heating and fusing. There is. When the elasticity of the toner becomes excessively strong, the brittleness of the toner may also become strong.
Therefore, for example, after the fixing process is performed on the sheet P in the image forming apparatus 1 (see FIG. 1), when the sheet P is folded as the post-processing by the post-processing apparatus 2, the sheet P is formed Image may be missing. More specifically, when a bending stress is applied to the sheet P, the image formed on the sheet P is also bent together with the sheet P. However, when the toner is highly brittle, the image may not be bent and chipped off.

In addition, when heat treatment is performed 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 heat treatment are not excessively slowed and excessively fast. It is preferable to change rapidly in the range of
With a temperature of 50 ° C. to 60 ° C., for example, when the sheet P is subjected to post-processing by the post-processing device 2 after fixing the sheet P in the image forming apparatus 1 (see FIG. 1) This is the temperature under the environment where the sheet P is present when the sheet P is transported to the discharge tray 130. In this temperature environment, the viscosity and elasticity of the toner are changed within a range of speed not to be excessively slowed and excessively fast, so that the sheet P is folded by the above-described post-processing device 2 or the discharge tray of the sheet P Depletion of the image on the sheet P after discharging to 130 is suppressed.

  Further, when the toner is heat-treated at a temperature of 50 ° C. to 60 ° C. after heat melting, a value obtained by dividing the loss coefficient tan δ1 after heat melting and before heat treatment by the loss coefficient 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 still more preferably 3 or more and 5 or less.

Here, the loss coefficient tan δ is an index indicating the viscoelasticity of the toner, and is a value obtained by dividing the loss elastic modulus of the toner by the storage elastic modulus (the ratio of the loss elastic modulus to the storage elastic modulus). As the loss coefficient tan δ is larger, the viscosity of the toner is stronger. In addition, the larger the value (tan δ1 / tan δ2) obtained by dividing the loss coefficient tan δ1 before heat treatment by the loss coefficient tan δ2 after heat treatment, the larger the speed at which the toner changes from a more viscous state to a more elastic state.
Hereinafter, a value obtained by dividing the loss coefficient tan δ1 of the toner after heat melting and before the heat treatment by the loss coefficient tan δ2 of the toner after the heat treatment is referred to as a loss coefficient ratio (tan δ1 / tan δ2).

When the heat treatment is performed at a temperature of 50 ° C. to 60 ° C. after the heating and melting of the toner, if the loss coefficient ratio (tan δ1 / tan δ2) is smaller than 2, the rate of change of elasticity of the toner after the heating and fusing is excessively low. Become. In this case, even after heating and melting, the elasticity of the toner does not become strong and the viscosity tends to be strong. Therefore, the aforementioned toner transfer is more likely to occur.
When the heat treatment is performed at a temperature of 50 ° C. to 60 ° C. after the heating and melting of the toner, if the loss factor ratio (tan δ1 / tan δ2) is larger than 6, the rate of change of elasticity of the toner after the heating and fusing is excessively high. Become. In this case, the elasticity of the toner becomes strong immediately after the heating and melting, and the brittleness of the toner also tends to become strong. Therefore, it is easy for a missing image to occur.

Further, the loss coefficient tan δ1 of the toner before the heat treatment is preferably 0.7 or more and 1.5 or less, and 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 smaller than 0.7, the elasticity of the toner is strong even before the heat treatment, and the elasticity of the toner further increases after the heat treatment and the brittleness of the toner also tends to be strong.
If the loss factor tan δ1 of the toner before the heat treatment is larger than 1.5, the viscosity of the toner before the heat treatment is excessively strong, and the state of the toner having the high viscosity tends to continue even when the heat treatment is performed.
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 hardly occur after the toner is heated and melted.

  In addition, the mixing ratio of the crystalline resin to the non-crystalline resin contained in the toner so that the viscosity and elasticity of the toner do not become too fast and too slow after the toner is heated and melted. Is preferably defined. In other words, it is preferable that the mixing ratio of the crystalline resin and the amorphous resin contained in the toner is determined so that the loss coefficient 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 small, it is difficult for the phase separation between the crystalline resin and the amorphous resin to proceed after the heating and melting of the toner, and the loss coefficient ratio (tan δ1 / tan δ2) is more than 2 Also tends to be smaller. In addition, the low temperature fixability described above is likely to deteriorate.
When the content of the crystalline resin is excessively large, the progress of phase separation between the crystalline resin and the amorphous resin becomes excessively fast after the heating and melting of the toner, and the loss coefficient ratio (tan δ1 / tan δ2) is more than 6 It is easy to get bigger.

  When a toner is manufactured 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 used. It is preferable to use it to produce a toner.

When a toner is manufactured using a crystal nucleating agent separately from the dispersion in which the crystalline resin is dispersed, the crystalline resin, the amorphous resin, and the crystal nucleating agent are easily localized in the toner. In this case, phase separation between the crystalline resin and the amorphous resin is less likely to progress after the toner is heated and melted. Therefore, even if the content of the crystal nucleating agent and the crystalline resin in the toner is increased, the loss factor ratio (tan δ1 / tan δ2) of the toner may not be larger than 2 in some cases.
When a crystalline nucleating agent bonded to a crystalline resin is used, phase separation between the crystalline resin and the non-crystalline resin is significantly promoted, and the loss factor ratio (tan δ1 / tan δ2) of the toner tends to be larger than six.

When a mixed dispersion is used to produce a toner, in the toner, the crystalline resin, the amorphous resin and the crystal nucleating agent will be present at positions which are not too close and too far from each other. In this case, although the phase separation between the crystalline resin and the non-crystalline resin proceeds, the progress of the phase separation is delayed compared to the case where the crystal nucleating agent is not used. Therefore, when the toner is manufactured using the mixed dispersion, the loss coefficient ratio (tan δ1 / tan δ2) is less likely to be larger than 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 are changed in a range that does not become excessively fast or too slow.

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 1.0 or less.
Here, the SP value is an index representing the solubility of the crystalline polyester resin and the amorphous polyester resin. The SP value is defined by the following equation (1).

In formula (1), ΔE represents cohesive energy (cal / mol), V represents molar volume (cm ³ / mol), and Δei is the evaporation energy (cal / atomic or atomic group) of the ith atom or atomic group Δvi represents the molar volume (cm ³ / atom or atomic group) of the ith 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 non-crystalline polyester resin is 0.5 or more, the toner on the paper is less likely to melt when the paper on which the image is formed is stored.
When the absolute value of the difference between the SP value of the crystalline polyester resin and the SP value of the non-crystalline polyester resin is 1.0 or less, the low temperature fixability of the toner is improved.

<Method of manufacturing toner>
Subsequently, a method of manufacturing the 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, the crystalline resin particles, the amorphous resin particles, the crystal nucleating agent particles, the colorant particles, and the releasing agent particles are hetero-aggregated in the toner raw material liquid to form the crystalline resin particles and the non-crystalline resin particles. Aggregated particles including crystalline resin particles, crystal nucleating agent particles, colorant particles, and releasing agent particles are formed (aggregation step).
Specifically, an aggregating agent is added to the toner raw material liquid, the pH of the mixed liquid is adjusted to be acidic, and heating is performed to the glass transition temperature of the resin particles, whereby the particles dispersed in the toner raw material liquid are aggregated and aggregated. Form particles.

Next, the aggregated particles are fused by heating the solution in which the aggregated particles are formed to a temperature equal to or higher than the glass transition temperature of the resin particles to form toner particles (forming step).
Through the above steps, a toner in which a crystalline resin, an amorphous resin, and a crystal nucleus material are dispersed is obtained. According to this toner, the loss factor ratio (tan δ1 / tan δ2) of the toner when the heat treatment is performed at 50 ° C. or more and 60 ° C. or less is 2 or more and 6 or less. Therefore, when heat treatment is performed at a temperature of 50 ° C. or more and 60 ° C. or less after the toner is heated and melted, the change rate of the viscoelasticity of the toner is within a range where the viscosity is not excessively strong or the brittleness does not become strong. It is determined in

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

The toner was prepared and evaluated. The execution conditions and the evaluation results are shown in Table 1 below.
Preparation of Amorphous Polyester Resin
First, the following monomers were prepared to prepare an amorphous polyester resin.
-Bisphenol A ethylene oxide 2.2 mol adduct: 230 parts by weight-Bisphenol A propylene oxide 2.2 mol adduct: 367 parts by weight-dimethyl terephthalate: 163 parts by weight-dimethyl fumarate: 12 parts by weight-dodecenyl succinic anhydride Substance: 227 parts by mass · trimellitic anhydride: 20 parts by mass

Next, while 2.2 mol adducts of bisphenol A ethylene oxide, 2.2 mol adduct of bisphenol A propylene oxide, dimethyl terephthalate, and dodecenyl succinic anhydride are charged into a container, 2.55 parts by mass of tin dioctanoate It was thrown in. Subsequently, the sample charged at 235 ° C. was reacted for 6 hours under a nitrogen gas flow, and then dimethyl fumarate and trimellitic anhydride were charged and reacted at 200 ° C. for 1 hour. The temperature was further raised to 220 ° C. over 5 hours, and the monomers were 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, in order to prepare a crystalline polyester resin, the following monomers were prepared.
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, 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 flow. Furthermore, the temperature was raised to 210 ° C. over 1 hour, the inside of the container was depressurized 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 25000, a number average molecular weight (Mn) of 10500, an acid value of 10.1 mg KOH / 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 above amorphous polyester resin, 25 parts by mass of the crystalline polyester resin, and 5 parts by mass of "NA-05" manufactured by ADEKA Corporation as a crystal nucleating agent are manufactured by Eurotech Co., Ltd. Cavitron CD1010 was dispersed using a modified disperser into a high temperature, high pressure type.

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

[Preparation of mixed resin particle dispersion (2)]
Except that 85 parts by mass of amorphous polyester resin, 15 parts by mass of crystalline polyester resin, and 2.4 parts by mass of NA-05 were used, the same method as the preparation method of mixed resin particle dispersion (1) was used, A mixed resin particle dispersion (2) was prepared.

[Preparation of mixed resin particle dispersion (3)]
Except that 80 parts by mass of the amorphous polyester resin, 20 parts by mass of the crystalline polyester resin, and 2.2 parts by mass of NA-05 are used, the same method as the preparation method of the mixed resin particle dispersion (1) is used. A mixed resin particle dispersion (3) was prepared.

[Preparation of mixed resin particle dispersion (4)]
Except that 75 parts by mass of amorphous polyester resin, 25 parts by mass of crystalline polyester resin, and 5.5 parts by mass of NA-05 were used, the same method as the preparation method of mixed resin particle dispersion (1) was used, A mixed resin particle dispersion (4) was prepared.

[Preparation of Amorphous Polyester Resin Particle Dispersion]
Amorphous polyester resin particle dispersion by the same method as the preparation method of mixed resin particle dispersion (1) except that crystalline polyester resin and NA-05 are not used with 100 parts by mass of amorphous polyester resin Was prepared.

[Preparation of Crystalline Polyester Resin Particle Dispersion]
A crystalline polyester resin particle dispersion was prepared by the same method as the preparation method of the mixed resin particle dispersion (1) except that the amorphous polyester resin and NA-05 were not used with 100 parts by mass of the crystalline polyester resin. Prepared.

Preparation of Black Pigment Dispersion
First, the following samples were prepared 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 exchange water and 33 parts by mass of an anionic surfactant were charged into the container. After dissolving the surfactant, 250 parts by mass of Regal 330 was added, and stirred and defoamed using a stirrer until no pigment became wet. After degassing, the remaining ion-exchanged water is added, and stirring is carried out for 10 minutes at 5,000 rpm using a homogenizer (Ultratarax (registered trademark) T50 manufactured by IKA Japan Co., Ltd.) to disperse Regal 330, and then 1 with a stirrer. Stir for days to degas. After degassing, Regal 330 was dispersed again by stirring at 6,000 rpm for 10 minutes using Ultra-Turrax T50, 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 left to stand for 72 hours to remove precipitates, and ion-exchanged water was added to obtain a black pigment dispersion adjusted to have a solid content concentration of 15%.
The volume average particle diameter of the particles in the obtained black pigment dispersion was 135 nm.

Preparation of Release Agent Dispersion
First, in order to prepare a release agent dispersion, the following samples were prepared.
Polyethylene-based wax (Poly Wax (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 are mixed, and a polywax is dissolved using a pressure discharge type homogenizer (Gorin homogeniser manufactured by Gaulin Co., Ltd.), and the polywax dispersion treatment is performed at a pressure of 5 MPa for 120 minutes. The mixture was dispersed for 360 minutes to obtain a mixture. The obtained mixed solution was cooled, and ion exchanged water was added thereto to obtain a release agent dispersion liquid adjusted to have a solid content concentration of 20.0%.
The volume average particle diameter of the particles in the obtained release agent dispersion was 225 nm.

[Preparation of Toner]
Example 1
The following samples were prepared to produce the toner of this example.
Mixed resin particle dispersion (1): 811 parts by mass Non-crystalline polyester resin particle dispersion: 349 parts by mass Crystalline polyester resin particle dispersion: 90 parts by mass Black pigment dispersion: 160 parts by mass Releasing Dispersion agent: 60 parts by mass, ion exchange water: 600 parts by mass, anionic surfactant (Dowfax (registered trademark) 2A1 manufactured by The Dow Chemical Company): 2.9 parts by mass

Next, all the above samples are charged into a container, and after adjusting the pH to 3.0 by adding nitric acid having a concentration of 1.0%, dispersion treatment is performed by stirring at a rotational speed of 3000 rpm using an UltraTurrax T50. 100 parts by mass of an aqueous solution of aluminum sulfate having a concentration of 2% was added. Thereafter, the rotational speed was increased to 5000 rpm and stirred for 5 minutes.
Subsequently, the temperature is raised to 40 ° C. at a temperature rising rate of 0.2 ° C./min, and then the temperature is raised to 53 ° C. at a temperature rising rate of 0.05 ° C / min to form first aggregated particles; The particle size was measured by Multisizer 2 (manufactured by Beckman Coulter, Inc.) every minute. The temperature was maintained when the volume average particle size of the first agglomerated particles became 5.0 μm, and 70 parts by mass of the amorphous polyester resin particle dispersion was charged over 5 minutes.

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

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

(Examples 2 to 10)
A toner was produced in the same manner as in Example 1 except that changes were made to Example 1 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 to Example 1 as shown in Table 1.
That is, in Comparative Example 1, the crystalline polyester resin particle dispersion was not used in preparation of the toner.
Further, in Comparative Examples 2 and 3, the mixed resin particle dispersion was not used in preparation of the toner.

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

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

  As the evaluation of the toners of Examples 1 to 10 and Comparative Examples 1 to 3, the evaluation of low-temperature fixability, the evaluation of bending image strength, the evaluation of abrasion resistance, and the 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]
The toners of Examples 1 to 10 and Comparative Examples 1 to 3 were used to form an image on a sheet.
Specifically, the developing device in the ApeosPort-V C7775 manufactured by Fuji Xerox Co., Ltd. was filled with toner, and the toner loading amount on paper was set as 1.0 mg / cm ² . In addition, 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 rear edge of the sheet, and the fixing process was performed with the temperature of the fixing device set at 140 ° C. .

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

[Evaluation of low temperature fixability]
The low temperature fixability of the toners of Examples 1 to 10 and Comparative Examples 1 to 3 was evaluated.
Specifically, solid images formed on the leading edge and the trailing edge of the sheet were visually observed to evaluate the degree of image defects. The evaluation criteria are as follows. Of the following evaluation criteria, the evaluation of ◎, ○ and △ was accepted, and the evaluation of x was rejected.
:: no image defect was confirmed at all ○: image defect was slightly confirmed but no problem in use △: image defect was slightly confirmed x: image defect was confirmed The larger the basis weight and the thicker the sheet, the easier it is for the heat given to the image in the fixing process to be dispersed to the sheet, so the low temperature fixability tends to deteriorate. In addition, since the heat is less likely to be transmitted to the toner on the paper more uniformly as the surface is rougher, the low temperature fixability tends to be deteriorated.

[Evaluation of bending image strength]
The bending image strength was evaluated for the toners of Examples 1 to 10 and Comparative Examples 1 to 3.
Specifically, a portion of the sheet on which a solid image was formed was mountain-folded, and a pressure of 10 g / cm ² was applied over the mountain-folded sheet for 1 minute. Then, the mountain fold was opened, and the condition of the image defect when the broken part was wiped with gauze was evaluated. The evaluation criteria are as follows. Of the following evaluation criteria, the evaluation of ◎, ○ and △ was accepted, and the evaluation of x was rejected.
:: no image defects were observed at all ○: image defects were only slightly confirmed, but no problem in use :: crack-like (width less than 500 μm) image defects were confirmed x: cracks Image defects (wider than 500 μm) were identified

In the image forming system 500 (see FIG. 1), when the sheet is folded by the post-processing apparatus 2, a portion of the sheet on which an image is formed may be folded. Further, when the sheet is transported after the folding process, a transport roll (not shown) may pass through a portion of the sheet on which an image is formed.
Therefore, evaluation of image defects when a portion of the sheet on which an image is formed is bent and then a portion that has been folded is wiped with gauze is regarded as evaluation of image strength when sheet folding processing and transport processing are performed. .

〔Evaluation results〕
The evaluation results of low temperature fixability are shown in Table 2.
As shown in Table 2, all of the toners of Examples 1 to 10 evaluated under any environment and any paper also passed.
Further, with regard to the toners of Comparative Examples 2 and 3, all those evaluated under any environment and any paper were all pass.

On the other hand, for the toner of Comparative Example 1, a defect in the image formed on the OK topcoat paper in a low temperature and low humidity environment was confirmed.
Regarding this, in Comparative Example 1, it is considered that the low temperature fixing property is lowered because the crystalline polyester resin particle dispersion liquid is not used in preparation of the toner.

The evaluation results of the bending image strength are shown in Table 3.
As shown in Table 3, all of the toners of Examples 1 to 10 evaluated under any environment and any paper also passed.
In addition, with regard to the toner of Comparative Example 1, all the products evaluated under any environment and any paper also passed.

On the other hand, with regard to the toners of Comparative Examples 2 and 3, image defects in a cracked shape (a width of more than 500 μm) were confirmed on the paper of OK Prince under a low temperature and low humidity environment.
Regarding this, in Comparative Examples 2 and 3, the crystalline polyester resin particle dispersion liquid was used in preparation of the toner while the mixed resin particle dispersion liquid was not used, so the toner loss coefficient ratio (tan δ1 / tan δ2) is 6 Too big. Therefore, the elasticity of the toner increases and the brittleness increases, and it is considered that the image on the sheet is cracked due to bending stress.

  According to the results of Examples 1 to 10 and Comparative Examples 1 to 3, by setting the loss factor ratio of the toner (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 is excessive. It was confirmed that it was necessary to set the range not to be late and not to be excessively fast.

DESCRIPTION OF SYMBOLS 1 ... image forming apparatus, 2 ... post-processing apparatus, 120 ... toner cartridge, 500 ... image processing system

Claims (12)

Binder resin made of heat-melting resin,
With colorants,
Including
Electrostatic image development characterized in that it is a visco-elastic body after heating and melting, and changes from a more viscous state to a more elastic state within a predetermined speed range with the passage of cooling time. For toner.   When heat treatment is performed at a predetermined temperature range after heating and melting, the change rate of the viscoelasticity is larger in a predetermined range than after heat treatment. Item 2. A toner for developing an electrostatic charge image according to item 1.   3. The toner according to claim 2, wherein the predetermined temperature range is 50.degree. C. or more and 60.degree. C. or less.   The ratio of the loss modulus to the storage modulus before heat treatment divided by the ratio of the loss modulus to the storage modulus after heat treatment is 2 or more and 6 or less. Toner for electrostatic image development.   5. The toner according to claim 4, wherein a ratio of the loss elastic modulus to the storage elastic modulus before heat treatment is 0.7 or more and 1.5 or less.   The toner for electrostatic image development according to claim 1, wherein the binder resin contains a crystalline resin and an amorphous resin.   7. The toner according to claim 6, wherein the binder resin causes phase separation between the crystalline resin and the non-crystalline resin as the cooling time elapses after the heating and melting. .   8. The electrostatic charge image according to claim 7, wherein a mixing ratio of the crystalline resin and the amorphous resin is determined such that a change rate of viscoelasticity is in the range of the predetermined speed. Developing toner. The binder resin further includes a crystal nucleating agent that promotes phase separation between the crystalline resin and the amorphous resin by bonding with the crystalline resin.
9. The toner according to claim 8, wherein the crystalline resin, the amorphous resin, and the crystal nucleating agent are dispersed. An aggregation step of aggregating the crystalline resin particles and the non-crystalline resin particles in a dispersion liquid in which the crystalline resin particles and the non-crystalline resin particles are dispersed to obtain aggregated particles;
The aggregated particles are heated and fused, and after heating and melting, it is a visco-elastic body, and changes from a more viscous state to a more elastic state within a predetermined speed range with the lapse of cooling time. Forming the toner particles;
Including
A method for producing a toner for developing an electrostatic charge image, wherein a mixing ratio of the crystalline resin particles and the non-crystalline resin particles in the aggregation step is determined to be in the range of the speed. The aggregated particles include a crystal nucleating agent that promotes phase separation between the crystalline resin particles and the amorphous resin particles by bonding with the crystalline resin.
11. The method for producing a toner for developing an electrostatic charge image according to claim 10, wherein the crystalline resin particles, the non-crystalline resin particles, and the crystal nucleating agent are dispersed in the dispersion. . An image carrier,
Charging means for charging the surface of the image carrier;
An exposure unit that exposes the charged image carrier to form an electrostatic charge image;
It contains a binder resin consisting of a heat-melting resin and is a visco-elastic body after heating and melting, and changes from a more viscous state to a more elastic state within a predetermined speed range with the lapse of cooling time. A developing unit that contains an electrostatic charge image developing toner and develops an electrostatic charge image formed on the surface of the image carrier;
A transfer unit configured to transfer an image formed on the surface of the image carrier to a recording medium;
Fixing means for fixing the image transferred to the recording medium;
An image forming apparatus comprising:

Images