JP2009092864A - Toner and manufacturing method for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner of excellent durability having a sufficiently fixed non-offset area capable of restraining background fogging, and capable of preventing surely the toner from being flocculated under a high temperature and high humidity environment. <P>SOLUTION: This toner contains a binding resin which is a polyester resin, a mold release agent which is a wax composition containing at least a paraffinic wax and a wax having an ester group, and a coloring agent, and is prepared through a process for mixing the waxes under a heating condition of (T1-10)-(T2+20)°C, where T1 is a temperature of a lower melting point, and T2 is a temperature of a higher melting point, out of a melting point Tmp of the paraffinic wax and a melting point Tmk of the wax having an ester group, a process for fusion-kneading the mixed wax with a mixture of the binding resin and the coloring agent, and a process for crushing thereafter a mixed composition prepared therein. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic toner and a method for producing the same, and more particularly to a full-color electrophotographic toner used in an image forming apparatus using a so-called electrophotographic method such as an electrostatic copying machine or a laser beam printer. And a manufacturing method thereof.

  In recent years, in the field of hard copying using electrophotography, there has been an increasing demand for lower energy (reduction of power consumption), higher speed, simplification and stabilization of the fixing system, and the fixing temperature is low. Therefore, there is a demand for a wide toner.

  In the technical field of full-color image formation, color reproduction is performed using three color toners of yellow, magenta, and cyan, and further, four color toners obtained by adding black to this. The charging, exposure, development, and transfer processes are repeated for each time, and the resulting toner image is melted, mixed (mixed), and fixed on a recording medium to form a full-color image.

  Thus, in color electrophotography in which toner images of different colors are superimposed on a recording medium by performing development and fixing a plurality of times, the fixing characteristics of the respective color toners are extremely important elements. In other words, in order to prevent the fixed toner particles from being diffusely reflected by light and hindering color reproduction, the toner must be melted so that no boundary is formed between the particles to increase transparency and widen the color reproduction range. In addition, there are many points that should be improved in terms of glossiness and gloss.

  In recent years, there has been an increasing demand for higher speed, and the contact time between the fixing device and the recording paper in the fixing process has been shortened in order to shorten the processing time for one recording paper. The non-offset area tends to narrow.

  For this reason, there is a need for an improvement in the release function of the release agent, and it is necessary to secure a certain amount of non-offset region, increasing the content of the release agent in the toner and dispersibility of the wax. It is necessary to ensure that the wax is supplied appropriately while reducing the viscosity of the toner.

In addition, it is necessary to design a high-durability toner with high speed, and for that purpose, the dispersibility of the wax contained in the toner is an important factor.
There are two actions of the wax, and one is an effect of improving the fixing characteristics. This is an anchor effect that prevents the low temperature offset by causing the seepage to start from a low temperature and maintaining strong adhesion to the recording paper at a low temperature. Another is that the surface of the fixing roller covers the surface of the fixing roller due to exudation at high temperatures, so that the wax enters between the toner and the fixing roller to reduce the adhesion between the toner and the fixing roller and prevent high temperature offset. It is a mold effect.

The wax exposed on the surface of the toner functions favorably in order to exert an anchor effect at low temperatures, but the wax is brittle and soft. May occur, and this may become a starting point and adhere to the charging member. Such adhesion to the charging member hinders the charging property, and thus causes troubles in actual shooting such as toner scattering and ground fogging.
In a high temperature and high humidity environment, the toners may aggregate and become difficult to be charged.
On the other hand, when the dispersibility of the wax becomes good, the above problem is overcome, but at the time of low temperature, the above-described anchor effect is not sufficiently exhibited.

In order to cope with the problems related to the toner as described above, for example, there is a technique for optimizing the dispersion state while using two kinds of waxes, separating the respective functions, and obtaining an appropriate exudation of the wax. Has been studied.
For example, Patent Document 1 below discloses a toner using low molecular weight polypropylene and carnauba wax as a release agent.
However, since the low molecular weight polyolefin wax has a relatively high melting point, there is a problem that an adequate wax exudation cannot be sufficiently ensured at a low temperature, and the anchor effect is insufficient.

Patent Document 2 below discloses a toner using a mixture of carnauba wax and nonpolar paraffin wax as a release agent.
According to this technique, a mixture of carnauba wax and nonpolar paraffin wax is used as a release agent, cyclohexanedimethanol, which is a polyhydric alcohol component, is used as a binder resin, and an acid value of 5 to 20 mgKOH / g. If so, a color toner having good fixability, glossiness, transparency and releasability can be provided without applying fixing oil in the fixing device.
However, nonpolar paraffin wax has a problem that it is difficult to ensure good dispersibility even if the acid value of the resin is increased as described above.

JP-A-6-266156 JP 2004-287218 A

  Therefore, in the present invention, in view of the above-described problems of the prior art, the generation of fine powder can be suppressed even when a full-color toner has a sufficiently fixed non-offset region and a long run is performed. An object of the present invention is to provide a toner that can prevent charging failure due to adhesion to a charging member, and can reliably prevent background fogging and toner aggregation in a high-temperature and high-humidity environment.

  According to the first aspect of the present invention, there is provided a toner containing at least a binder resin, a release agent, and a colorant, wherein the binder resin is a polyester resin, and the release agent is at least a paraffin wax. And a wax composition containing a wax having an ester group, wherein the temperature of the lower melting point of the melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having the ester group is T1, and the melting point is high. When T2 is the temperature of the other, a step of mixing these under heating conditions of (T1-10) ° C. or higher and (T2 + 20) ° C. or lower, a step of melt-kneading with the binder resin and colorant mixture, Then, a toner is provided that is produced through a pulverizing step.

  According to a second aspect of the present invention, there is provided the toner according to the first aspect, wherein the paraffinic wax has a melting point Tmp of 65 ≦ Tmp ≦ 80 (° C.).

  In the invention of claim 3, the lower temperature T1 of the melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having an ester group is equal to the melting point Tmp of the paraffinic wax. A toner according to claim 1 or 2 is provided.

  According to a fourth aspect of the invention, there is provided the toner according to any one of the first to third aspects, wherein the paraffinic wax has an acid value of 3 mgKOH / g or less.

  The invention according to claim 5 is characterized in that the mixture ratio of the paraffinic wax and the wax having an ester group is 1: 2 to 2: 1. The toner described in 1. is provided.

  According to a sixth aspect of the present invention, there is provided the toner according to any one of the first to fifth aspects, wherein the penetration of the paraffinic wax in a temperature environment at 25 ° C is 7 or less. To do.

  The invention according to claim 7 is characterized in that the total amount of the mixture of the paraffinic wax and the wax having an ester group is 3 to 8 parts by weight with respect to 100 parts by weight of the toner. A toner according to any one of the above is provided.

  In the invention of claim 8, an open roll kneader is applied in the step of melt-kneading the mixture of the paraffin wax and the wax having an ester group and the mixture of the binder resin and the colorant. A toner according to any one of claims 1 to 7 is provided.

  The invention according to claim 9 is a method for producing a toner containing at least a binder resin, a release agent, and a colorant, wherein the release agent includes at least a paraffinic wax and a wax having an ester group. The melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having an ester group are set to a temperature T1 having a lower melting point and a temperature T2 having a higher melting point. (T1-10) Mixing under heating conditions not lower than (T2 + 20) ° C. to obtain a wax composition, followed by melt-kneading the mixture of the binder resin and the colorant and the wax composition And a process for pulverizing the toner, and a method for producing the toner.

  According to a tenth aspect of the present invention, there is provided the method for producing a toner according to the ninth aspect, wherein the paraffinic wax has a melting point Tmp of 65 ≦ Tmp ≦ 80 (° C.).

  In the invention of claim 11, of the melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having an ester group, the lower temperature T1 is set equal to the melting point Tmp of the paraffinic wax. A method for producing a toner according to claim 9 or 10 is provided.

  The invention according to claim 12 provides the toner production method according to any one of claims 9 to 11, wherein the paraffinic wax has an acid value of 3 mgKOH / g or less.

  In the invention of claim 13, the mixture ratio of the paraffinic wax and the wax having an ester group is 1: 2 to 2: 1. A method for producing the toner described in 1) is provided.

  14. The toner production according to claim 9, wherein the penetration of the paraffinic wax in a temperature environment at 25 ° C. is 7 or less. Provide a method.

  According to a fifteenth aspect of the present invention, the total amount of the mixture of the paraffinic wax and the wax having an ester group is 3 to 8 parts by weight with respect to 100 parts by weight of the toner. A method for producing a toner according to any one of claims 14 to 14, is provided.

  According to the invention of claim 16, in the step of melt-kneading the mixture of the paraffinic wax and the wax having an ester group and the mixture of the binder resin and the colorant, an open roll kneader is used. The toner manufacturing method according to claim 9, which is applied.

  According to the present invention, there is a sufficient non-offset area for fixing, and even when running for a long time, generation of fine powder can be suppressed, charging failure due to adhesion to the charging member, ground fogging can be prevented, and high temperature can be prevented. A toner capable of effectively suppressing aggregation in a high humidity environment was obtained.

  Embodiments of the present invention will be specifically described below, but the present invention is not limited to the following examples.

The toner of the present invention is a toner containing at least a binder resin, a release agent, and a colorant. The binder resin is a polyester resin, and the release agent is a wax composition containing at least a paraffinic wax and a wax having an ester group.
In the toner of the present invention, when the melting point Tmp of the paraffin wax and the melting point Tmk of the wax having an ester group is T1, the lower melting point is T1, and the higher melting point is T2. Produced through a step of mixing under heating conditions of (T1-10) ° C. to (T2 + 20) ° C., followed by a step of melt-kneading the mixture of the binder resin and the colorant and a step of pulverizing thereafter. It shall be assumed.

In the heat mixing of the wax, it is necessary to disperse each wax particle to form a compatible state.
In this step, if the heating condition is too lower than the melting point of the wax, the two types of wax cannot be sufficiently melted and a compatible state cannot be formed.
On the other hand, if the heating condition is set higher than the melting point of the wax, the viscosity of the wax becomes low, the stirring force becomes insufficient, and the mixed state may be deteriorated.
Therefore, in the present invention, the heating conditions are specified as described above, and the wax is sufficiently mixed to obtain a good compatible state.
Among the waxes, the wax having an ester group is easily compatible with the polyester resin, and therefore, by using this, a toner having good dispersibility and finally having a sufficient non-offset region for fixing. Is obtained.

In the toner of the present invention, the melting point Tmp of the paraffin wax is preferably 65 ≦ Tmp ≦ 80 (° C.).
Paraffin wax is easy to bleed out in a polyester resin and is a sharp melt, so it mainly exhibits a function of soaking into recording paper during fixing. By specifying the melting point Tmp of the wax as 65 ≦ Tmp ≦ 80 (° C.), the non-offset range on the low temperature side due to the effect of soaking into the recording paper can be expanded.
If the melting point Tmp is lower than 65 ° C., the paraffinic wax present on the toner surface mainly increases adhesion to the charging member and cohesion between the toners, which adversely affects charging failure and high-temperature storage stability. Cause.
On the other hand, if the melting point Tmp is higher than 80 ° C., it is difficult to obtain the effect of seeping out on the low temperature side, and it has been confirmed that the non-offset range cannot be expanded.

In the toner of the present invention, the lower temperature T1 between the melting point Tmp of the paraffin wax and the melting point Tmk of the wax having an ester group is equal to the melting point Tmp of the paraffin wax. Is preferred.
Since paraffin wax is less compatible with polyester resin than ester wax, paraffin wax is mainly used as a soaking effect on paper on the low temperature side, and ester wax is used as a releasing effect on fixing members on the high temperature side. Is easy to function. Therefore, by specifying the temperature T1 = Tmp having the lower melting point among these, it is possible to expand the non-offset range of fixing on both the low temperature side and the high temperature side.

  In the present invention, the paraffin wax preferably has an acid value of 3 mgKOH / g or less. If the oxidation is greater than 3 mgKOH / g, bleeding out is difficult, the effect of soaking into the recording paper on the low temperature side is insufficient, and adverse effects such as aggregation between toners under high temperature and high humidity due to the wax exposed on the surface. May occur.

The mixture ratio of the paraffin wax and the wax having an ester group is preferably 1: 2 to 2: 1.
If the mixing ratio is less than 1: 2, the ratio of paraffin wax is too low, and the effect of low temperature offset becomes insufficient. On the other hand, if the mixing ratio is larger than 2: 1, the ratio of the paraffinic wax is too high, so that it cannot sufficiently form a compatible state with the ester wax, and the dispersibility deteriorates. This causes a problem that the durability and storage stability of the obtained toner deteriorate. On the other hand, if the ratio of the ester wax is too low, the effect of high temperature offset property cannot be obtained sufficiently. Therefore, by specifying the mixture ratio of the paraffin wax and the ester wax in the range of 1: 2 to 2: 1, it is possible to obtain a high-quality toner having excellent durability and storage stability and high non-offset property.

The penetration of the paraffin wax in an environment of 25 ° C. is preferably 7 or less.
Paraffin wax is obtained by preheating and mixing with carnauba wax. However, when a pulverization method is applied, the paraffin wax is easily cracked at the wax interface and exposed to the surface of the finally obtained toner. Probability is high.
If the penetration of the wax exposed on the surface is greater than 7, the wax is too soft and may adhere excessively to the adjacent toner, carrier, etc., thereby hindering these functions.
However, it was confirmed that by specifying the wax penetration to 7 or less, excessive adhesion of the wax exposed on the surface to the toner or carrier can be prevented.

In addition, the total amount of the mixture of the paraffin wax and the wax having an ester group is preferably 3 to 8 parts by weight with respect to 100 parts by weight of the toner.
If the amount of wax relative to the toner is less than 3 parts by weight, a sufficient effect regarding the fixing offset property cannot be obtained.
On the other hand, when the amount of the wax relative to the toner is more than 8 parts by weight, the dispersibility becomes insufficient, and the exposed amount of the wax becomes excessive and adheres to the adjacent toner or carrier. Inhibit. Furthermore, since the wax is crystalline, if it is excessive, light is refracted, resulting in a problem that sufficient transparency cannot be obtained in a full color toner.

  When producing the toner of the present invention, in the step of melt-kneading the mixture of the paraffinic wax and the wax having an ester group and the mixture of the binder resin and the colorant, an open roll type kneader It is desirable to apply. Since this open roll type kneader exhibits a high dispersion function even at a relatively high viscosity, the wax can be more effectively dispersed.

Next, the material constituting the toner of the present invention will be specifically described.
A polyester resin is used as the binder resin.
The polyester resin preferably has an acid value, and is preferably 5 mgKOH / g or more from the viewpoint of ensuring wax dispersibility, and is preferably 30 mgKOH / g or less from the viewpoint of environmental characteristics. Also, from the viewpoint of control of thermal characteristics, it is preferable to specify in such a numerical range particularly for a full color toner.
Specifically, the polyester resin is synthesized from the following polyhydric alcohol and a polyvalent carboxylic acid component.
Examples of the polyhydric alcohol component include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 2,3-butanediol, diethylene glycol, triethylene glycol, and 1,5-pentanediol. 1,6-hexanediol, neopentylene glycol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polypropylene glycol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylene And dihydric alcohols such as bisphenol A alkylene oxide adducts such as bisphenol A.
In addition, trihydric or higher polyhydric alcohols can also be used to make the polymer non-linear to such an extent that no tetrahydrofuran-insoluble matter is generated.
Specific examples of the trihydric or higher alcohol component include glycerin, sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, pentaerythritol, 1,2,4-butanetriol, 1, Examples include 2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene.
Examples of the polyvalent carboxylic acid component include maleic acid, fumaric acid, mesaconic acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, terephthalic acid, isophthalic acid, cyclohexanedicarboxylic acid, malonic acid, succinic acid, adipine Examples thereof include dibasic carboxylic acids such as acid, sebacic acid, glutaric acid, alkyl succinic acid (for example, n-octyl succinic acid, n-dodecenyl succinic acid), acid anhydrides and alkyl esters thereof.

Next, the colorant will be described.
As the colorant of the toner of the present invention, various known colorants for yellow, magenta, cyan and black can be used.
Examples of the yellow colorant include C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 5, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 15, C.I. I. Examples thereof include azo pigments such as CI Pigment Yellow 17, and inorganic pigments such as yellow iron oxide and ocher.
Examples of the dye include C.I. I. Nitro dyes such as Agit Yellow 1 and C.I. I. Solvent Yellow 2, C.I. I. Solvent Yellow 6, C.I. I. Solvent Yellow 14, C.I. I. Solvent Yellow 15, C.I. I. Solvent Yellow 19, C.I. I. Examples thereof include oil-soluble dyes such as Solvent Yellow 21.
In particular, C.I. I. Benzidine pigments such as CI Pigment Yellow 17 are preferable from the viewpoint of color.

  Examples of the magenta colorant include C.I. I. Pigment red 49, C.I. I. Pigment red 57, C.I. I. Pigment red 81, C.I. I. Pigment red 122, C.I. I. Solvent Red 19, C.I. I. Solvent Red 49, C.I. I. Solvent Red 52, C.I. I. Basic Red 10, C.I. I. Disperse Red 15 etc. are mentioned. In particular, C.I. I. A quinacridone pigment such as CI Pigment Red 122 is preferable from the viewpoint of color.

  Examples of cyan toner colorants include C.I. I. Pigment blue 15, C.I. I. Pigment blue 16, C.I. I. Solvent Blue 55, C.I. I. Solvent Blue 70, C.I. I. Direct Blue 25, C.I. I. Direct blue 86 etc. are mentioned. In particular, C.I. I. A copper phthalocyanine pigment such as CI Pigment Blue 15 is preferable from the viewpoint of color.

Carbon black is preferred as the black colorant.
Carbon black can be appropriately selected from channel black, loin black, disc black, gas furnace black, oil furnace black, acetylene black, and the like.

In addition, a charge control agent may be blended in the toner of the present invention for the purpose of controlling the triboelectric chargeability.
As the charge control agent, positive charge control and negative charge control are used according to the charging characteristics of the toner.
As the charge control agent for controlling positive charge, an organic compound having a basic nitrogen atom can be applied, for example, basic dye, quaternary ammonium salt, aminopyrine, pyrimidine compound, polynuclear polyamino compound, aminosilanes, nigrosine base, etc. Is mentioned.
Examples of the charge control agent for negative charging include oil-soluble dyes such as oil black or spiron black, metal-containing azo dyes, metal salts of naphthenic acid, metal salts of alkyl salicylic acid, fatty acid soaps, and resin acid soaps.
The amount of the charge control agent described above is 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the binder resin. As the color toner, a colorless quaternary ammonium salt or an alkyl salicylic acid metal salt is suitable.

Next, the release agent constituting the toner of the present invention, that is, the wax will be described.
The wax in the present invention is a melt-mixed paraffin wax and ester wax.
Paraffinic wax is obtained by separating and extracting hydrocarbons with good crystallinity from the portion of crude oil distilled under reduced pressure. Since the main component is normal paraffin, the molecular weight is relatively small, the melting point is low, and it is relatively sharp melt.
On the other hand, ester waxes can be obtained by synthesizing higher fatty acids and higher alcohols, and naturally derived waxes can also be used.
Examples of naturally occurring waxes include animal-derived beeswax, whale wax, shellac wax, plant-derived carnauba wax, wood wax, rice bran wax (rice wax), candelilla wax, and mineral-derived montan wax. In particular, a hard carnauba wax having a relatively high melting point is suitable.
The paraffin wax preferably has a melting point of 65 ° C. to 80 ° C., and the penetration at 25 ° C. is preferably 7 or less. Further, when ester wax and paraffin wax are used in combination, an endothermic peak measured by a differential scanning calorimeter (hereinafter abbreviated as DSC) is 65 to 80 ° C. in order to exert a bleeding effect in a low temperature region. Things are good.

The DSC is measured according to JIS-K7122-1987, and the endothermic peak temperature is the melting point.
Further, the penetration specified as described above is a measurement method for determining the hardness of the wax by a method defined in JIS standard (K-2235-5.4). In general, under a specified temperature condition with a predetermined measuring device, a load of 100 g is applied to a predetermined needle, and the number of mm that penetrates the sample in 5 seconds is measured. The desired penetration.

In addition to the materials described above, inorganic fine particles and resin fine particles are externally added to the toner of the present invention.
Examples of the inorganic fine particles include fatty acid metal salts, zinc stearate, calcium stearate, lead stearate, zinc oxide powder, aluminum oxide powder, titanium oxide powder, and fine powder silica.
Examples of the resin fine particles include melamine resins.
These external additives are contained in an amount of 0.01 to 10 parts by weight with respect to 100 parts by weight of the toner, more preferably 0.1 to 5 parts by weight. Can be used.

In the toner of the present invention, when the melting point Tmp of the paraffin wax and the melting point Tmk of the wax having an ester group are set to a temperature T1 having a lower melting point and a temperature T2 having a higher melting point, (T1-10) ) Mixing under heating conditions of not lower than T ° C. and not higher than (T2 + 20) ° C. to obtain a wax composition, and subsequently melting and kneading the mixture of the binder resin and the colorant and the wax composition; It is produced through a pulverizing step.
That is, the toner of the present invention is produced through each process of premixing, kneading, cooling, and then pulverizing and classifying the raw material.
As a pre-stage of the pre-mixing step, two types of waxes used as release agents are mixed in a melted state in advance. The apparatus for mixing and melting the wax is not particularly limited.
Moreover, it is preferable to apply an open roll type kneader in the kneading step. This can be effectively kneaded even under low temperature and high viscosity conditions, and the dispersibility of the wax can be improved.
As the toner of the present invention, a toner having an average particle diameter of 3 μm to 15 μm after the pulverization step and the classification step is applied.
In order to improve the image quality, a small particle size toner having an average particle size of 9 μm or less is used, and in order to further improve the image quality, a small particle size toner having an average particle size of 5 μm to 8 μm is used. It is desirable.

The toner of the present invention can be applied as a non-magnetic one-component developer or a two-component developer.
When used as a two-component developer, iron powder, ferrite, or the like can be applied as a carrier, and an acrylic resin or a fluororesin may be coated as necessary. The particle size of the carrier is 20 μm to 100 μm, and more preferably 30 μm to 60 μm.

〔Example〕
Hereinafter, specific examples and comparative examples of the toner of the present invention were prepared and the characteristics were evaluated.

<Preparation of sample toner>
(Examples 1 to 19), (Comparative Examples 1 to 4)
Under the temperature conditions shown in Table 1 below, two types of waxes were heated and mixed using a heating mixer (manufactured by Aichi Electric Co., Ltd.), cooled, and then pulverized with a cutter mill to prepare a molten mixture of the wax composition.
The binder resin is 100 parts by weight of the polyester resin, the mixed wax in parts by weight shown in Table 1 below, 4 parts by weight of the copper phthalocyanine pigment as the colorant, and 1 part by weight of the zirconium salt of salicylic acid as the charge control agent. Are mixed using a Henschel mixer, and then subjected to a kneading process using a kneader shown in Table 1 below. After classification with a fluid bed grinder and a rotor classifier, the average particle size is 8 μm. A toner was obtained.
To this toner, a HMDS-treated silica having an average particle diameter of 12 nm and a HMDS-treated silica having an average particle diameter of 40 nm were externally added as a fluidizing agent to obtain a sample toner for evaluation.
Each sample toner shown in Table 1 and a ferrite carrier were mixed to prepare a two-component developer having a toner concentration of 4%.

<Evaluation of toner>
The following tests were carried out and evaluated for the two-component developers of Examples 1 to 19 and Comparative Examples 1 to 4 produced as described above.

(Fixing test)
An unfixed image was prepared by using an image forming apparatus (Ricoh Copier (Imagio Neo C355)) as an adhesion amount of 4.0 g / m ² with the two-component developer.
Next, the paper feed speed is 120 mm / sec using an external fixing machine that can freely set the roller temperature, which is a modification of the fixing device (oilless method) of the image forming apparatus (Ricoh Copier (Imagio Neo C355)). The temperature was changed by 5 ° C in a range from 100 ° C to 210 ° C. At this time, the so-called offset phenomenon in which the image is re-transferred to the non-image portion was observed on the fixing roller and the recording paper, and the temperature at which the image was not re-transferred was defined as the non-offset temperature.
This non-offset temperature range is 70 ° C. or higher, ◎, 60 ° C. or higher and lower than 70 ° C., 50 ° C. or higher and lower than 60 ° C., and 50 ° C. or lower. , ○, △, × evaluated in four stages.

(Long-term running test)
Using the image forming apparatus (Ricoh Copier (Imagio Neo C355)), the sample two-component developer prepared as described above was subjected to a printing durability test of 50,000 sheets under a condition of 5% original density. .
With respect to the image density of the first fixed image and the fixed image of the 50,000th sheet, the density difference between the measurement unused paper and the white paper portion of the fixed image is measured by a reflection densitometer (Macbeth). A concentration difference was detected. If the density difference is 0.01 or less, ◎, 0.01 to 0.02 is good, ○ is 0.02 to 0.03, △ is greater than 0.03, x is better. To ◎, ○, Δ, and ×.
Further, the toner of the developer after the image formation on the 50,000th sheet is removed by blow-off, and 1 g of the toner washed with a surfactant is collected, dissolved in THF, and a spectrophotometer (CT3500 The absorbance was measured using Hitachi, Ltd.
A calibration curve of the toner amount (concentration) of the two-component developer prepared as described above and the absorbance measured as described above was prepared, and thereby the amount of toner contaminating the carrier was quantified.
If the amount of toner contaminated with 1 g of the carrier after forming 50,000 images is 0.1 mg or less, ◎, 0.1 to 0.2 mg, ○, 0.2 to 0 .3 mg was evaluated as Δ, and when it was larger than 0.3 mg, X was evaluated from four points of ◎, ○, Δ, and X from the better.

(Toner storage stability measurement)
After stirring 5.0 g of the toner prepared as described above, the toner is placed in a metal petri dish so that the bottom is uniformly covered.
It was allowed to stand for 18 hours in a constant temperature bath at a temperature of 50 ° C. and a humidity of 45%, and then naturally cooled to room temperature, and the toner caking state was confirmed.
○ If the powder is completely powdered, or if there is a small lump but can be easily crushed by stirring with a micro spatula, △ indicates that there is a small lump that cannot be easily crushed even if swirled. The state that could not be easily crushed was evaluated as x, and the evaluation was made in three stages: ◯, Δ, and x.

  Table 2 below shows the evaluation of the above-described fixing characteristics, long-term running characteristics, toner storage stability, and the overall determination.

In Example 1, a toner having a wide non-offset range, stable long-term running characteristics, and good storage stability was obtained.
In Examples 2 to 5, since the melt mixing temperature is high or low, the dispersibility of the wax is slightly deteriorated, and the long-term running characteristics are slightly unstable, but the toner has good fixability and storage stability. was gotten.
In Example 6, since the melting point of the paraffin wax was slightly low, the carrier contamination and the storage stability were slightly deteriorated, but a toner having good characteristics in practical use was obtained.
In Example 7, since the blending ratio of the paraffin wax was low, the non-offset range on the low temperature side was slightly narrowed, but a toner having good characteristics in practical use was obtained.
In Example 8, since the blending ratio of paraffin wax was large and the ratio of ester wax was small, the non-offset range on the high temperature side was slightly narrowed, and carrier contamination occurred during long-term running, but practically good. A toner having various characteristics was obtained.
In Example 9, since the total amount of added wax was small, the non-offset area was narrowed as a whole, but this was not a problem level in practical use, and a good toner was obtained.
In Example 10, since the amount of the wax added was as large as 8 parts by weight, carrier contamination occurred slightly during long-term running, but a good toner with a wide non-offset range was obtained.
In Example 11, since the acid value of the paraffin wax was high, the dispersibility of the paraffin wax was improved, but the non-offset range on the low temperature side was narrowed and the environment dependency was increased. The storage stability of deteriorated. However, it was a level with no problem in practical use.
In Example 12, since the penetration of the wax was high, carrier adhesion was likely to occur due to the influence of the wax exposed on the toner surface, the carrier was contaminated during long-term running, and a slight fogging occurred due to a decrease in charge. However, it was a level with no problem in practical use.
In Example 13, since the melting point of paraffin wax was high, the non-offset range on the low temperature side was narrowed and the non-offset range was slightly narrowed. However, a toner having good characteristics with respect to ground cover and storage stability was obtained. .
In Example 14, since the melting point of the paraffin wax was low, the non-offset range of fixing was expanded, but the carrier was contaminated during long-term running, and a slight fogging occurred due to a decrease in charging, but there was no practical problem. It was a level.
In Example 15, since the ratio of paraffin wax was small, the non-offset range on the low temperature side was narrowed and the non-offset range was slightly narrowed, but a toner with good characteristics with respect to ground cover and storage stability was obtained. .
In Example 16, since the ratio of the paraffin wax was large, the dispersion state of the wax was slightly deteriorated, so that the carrier contamination and the storage stability were slightly deteriorated, but the level was not problematic in practical use.
In Example 17, since the addition amount of the wax was as small as 2 parts by weight, the non-offset range was slightly narrowed, but a toner with good ground fog and storage stability was obtained.
In Example 18, since the amount of wax added was as large as 8 parts by weight, the non-offset range of fixing was expanded, but on the other hand, carrier contamination occurred in the long-term running test, and a slight fogging occurred due to a decrease in charging. However, there was no problem in practical use.
In Example 19, since a biaxial extrusion kneader was used as the kneading apparatus, the dispersibility of the wax became insufficient, carrier contamination was uttered, and the storage stability was slightly deteriorated. However, there was no problem in practical use.

  In Comparative Examples 1 to 4, since the melt mixing temperature is too high or too low, sufficient dispersibility of the wax cannot be ensured, and carrier contamination occurs during long-term running. This caused a decrease in charge and deterioration of the ground cover. Moreover, preservability also deteriorated and became insufficient as a practical level.

Claims (16)

A toner containing at least a binder resin, a release agent, and a colorant,
The binder resin is a polyester resin,
The release agent is a wax composition containing at least a paraffinic wax and a wax having an ester group,
Of the melting point Tmp of the paraffin wax and the melting point Tmk of the wax having an ester group, T1 is the temperature with the lower melting point, and T2 is the temperature with the higher melting point. It is produced through a step of mixing these under heating conditions of (T2 + 20) ° C. or lower, a step of melt-kneading with the binder resin and colorant mixture, and a step of pulverizing. Toner.   The toner according to claim 1, wherein the paraffin wax has a melting point Tmp of 65 ≦ Tmp ≦ 80 (° C.).   3. The lower temperature T1 of the melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having an ester group is equal to the melting point Tmp of the paraffinic wax. The toner described.   The toner according to claim 1, wherein the paraffin wax has an acid value of 3 mgKOH / g or less.   The toner according to claim 1, wherein a mixture ratio of the paraffinic wax and the wax having an ester group is 1: 2 to 2: 1.   The toner according to claim 1, wherein a penetration of the paraffin wax in a temperature environment of 25 ° C. is 7 or less.   The total amount of the mixture of the paraffin wax and the wax having an ester group is 3 to 8 parts by weight with respect to 100 parts by weight of the toner. toner.   2. An open roll kneader is used in the step of melt-kneading the mixture of the paraffin wax and the wax having an ester group and the mixture of the binder resin and the colorant. The toner according to any one of Items 7 to 7. A method for producing a toner containing at least a binder resin, a release agent, and a colorant,
The release agent is a wax composition having at least a paraffinic wax and a wax having an ester group,
Of the melting point Tmp of the paraffin wax and the melting point Tmk of the wax having an ester group, the temperature T1 having the lower melting point and the temperature T2 having the higher melting point are (T1−10) ° C. or more (T2 + 20) Mixing under heating conditions of ℃ or less to obtain a wax composition;
Subsequently, a step of melt-kneading the mixture of the binder resin and the colorant and the wax composition;
And a pulverizing step thereafter.   10. The toner manufacturing method according to claim 9, wherein the paraffin wax has a melting point Tmp of 65 ≦ Tmp ≦ 80 (° C.).   11. The lower temperature T1 of the melting point Tmp of the paraffinic wax and the melting point Tmk of the wax having an ester group is equal to the melting point Tmp of the paraffinic wax. 2. A method for producing the toner according to 1.   The method for producing a toner according to any one of claims 9 to 11, wherein the paraffin wax has an acid value of 3 mgKOH / g or less.   The method for producing a toner according to any one of claims 9 to 12, wherein a mixture ratio of the paraffin wax and the wax having an ester group is 1: 2 to 2: 1.   14. The toner production method according to claim 9, wherein a penetration of the paraffin wax in a temperature environment of 25 ° C. is 7 or less. 15.   15. The total amount of the mixture of the paraffin wax and the wax having an ester group is 3 to 8 parts by weight with respect to 100 parts by weight of the toner. Toner production method.   An open roll kneader is applied in the step of melt-kneading the mixture of the paraffin wax and the wax having an ester group and the mixture of the binder resin and the colorant. The toner production method according to any one of 9 to 15.