JP2010113279A - Toner production method, toner obtained by the production method and image forming method and process cartridge using the toner - Google Patents

Abstract

The present invention provides a toner manufacturing method capable of finely dispersing a large amount of a release agent in a binder resin using an open roll kneader, an image forming method using the toner, and a process cartridge.
At least a binder resin which may contain a plurality of resins having different softening temperatures and a toner raw material containing a release agent are mixed, and the resulting mixture is not lower than the softening temperature Tm-20 (° C.) of the binder resin. To the open roll kneader in which the temperature of the front roll (3) is controlled to be higher than the temperature of the back roll (4) while maintaining the preheating temperature, Is pulverized and classified into toner. A process cartridge is formed using the obtained toner to form an image. Tm is measured by a flow tester, and corresponds to the lowest softening temperature when a plurality of resins having different softening temperatures are included.
[Selection] Figure 1

Description

  The present invention relates to a toner manufacturing method, a toner obtained by the manufacturing method, an image forming method using the toner, and a process cartridge.

  In recent years, low-end laser printers are required to be small and low in cost. In order to reduce the size, a fixing method that does not require an oil application mechanism is essential, and among them, a heat roller fixing method that has a simple apparatus configuration and is easy to handle is widely used. However, in the heat roller fixing method, since the fixing member is in direct contact with the toner, there is an offset phenomenon in which a part of the molten toner is transferred to the fixing member and the molten toner is transferred to a recording medium such as transfer paper after one rotation of the roller. There was a problem that it occurred. Therefore, it is necessary to put a release agent such as a low molecular weight wax in the toner.

  On the other hand, in developing devices, a method of charging toner by bringing a toner into contact with a regulating blade or carrier is widely used. However, a toner containing a release agent is exposed to the surface of the toner when contacting the regulating blade or carrier. There is a problem in that the release agent exposed to the surface adheres to and adheres to the regulating blade and the carrier.

  In order to solve the above problem, it is necessary to suppress the exposure amount of the release agent on the toner surface. As a method for this, the release agent is used to reduce the dispersion diameter of the release agent in the toner and to secure the fixing property. A method of increasing the amount of addition (high filling and high dispersion of a release agent) has been studied.

  In order to achieve high filling and high dispersion of the release agent, for example, a method of reducing the particle size of the release agent in advance as described in Patent Document 1 can be mentioned. However, the method of Patent Document 1 has a problem in that it is limited due to restrictions such as the type of resin (molecular weight, resin melt viscosity, etc.) and the type of release agent (softening temperature, molecular weight, domain diameter, etc.). .

As a method for producing a toner in which wax is uniformly dispersed in a binder resin, for example, a production method using a thermally controlled kneading extruder is known (see, for example, Patent Document 2).
Alternatively, there has been proposed a toner kneading method in which a mixture containing a binder resin and a colorant is previously melt-kneaded, and supplied to a continuous two-roll kneader in a molten state, and melt-kneaded (for example, Patent Documents). 3). As a result, the loss of the toner material is suppressed, and the dispersibility of the colorant in the binder resin is improved (for example, in the examples, the formulation comprising each component of the binder resin, the colorant, and the charge control agent is used. (Toner is manufactured. No release agent is included.)
In addition, a toner manufacturing method has been proposed in which a toner raw material mixture containing a binder resin, a colorant, and a release agent is melted in advance, and this molten mixture is kneaded by an open type roll mill (see, for example, Patent Document 4). . Thereby, it is said that problems such as scattering and sagging of the kneaded material containing a large amount of the release agent are suppressed.
Further, using a two-roll kneader, a first kneading step (melting kneading of a raw material mixture containing a binder resin and a colorant: first kneading temperature) and a second kneading step (kneaded product of the first kneading step) A method of manufacturing a toner by melting and kneading a binder resin, a release agent, and a charge control agent (second kneading temperature) has been proposed (for example, see Patent Document 5). Thereby, the dispersibility of the toner additive material is improved.
Also, a first kneading step in which a raw material mixture containing a binder resin and a colorant is melt kneaded using a two-roll kneader, and the kneaded material obtained in the first kneading step is the same or different kind of binder resin. There has been proposed a method for producing toner by a second kneading step in which a mixture diluted in (1) is melt-kneaded using an extruder (see, for example, Patent Document 6). This improves the dispersibility of the toner additive material and maintains the resin characteristics.
The applicant previously kneaded the binder resin, release agent, pigment, and charge control agent in a raw material mixer (for example, using two rolls), rolled and cooled, and then pulverized and classified into toner. In addition, a manufacturing method for reusing a fine toner smaller than a predetermined particle diameter has been proposed (for example, see Patent Document 7). In this method, the ratio (Ha / Aa) of the temperature of the kneaded product at the kneading discharge port when reusing the fine toner and the thickness of the rolling cooling product (Ha / Aa), and the temperature of the kneaded product at the kneading discharge port when not reusing the fine toner By defining the ratio of the thickness ratio (Hn / An) of the rolling cooling product, it is possible to ensure the acidity of the release agent or the like in the binder resin.

As described above, various methods of mixing raw materials such as a binder resin, a release agent, and a colorant have been studied when producing toner. At this time, in order to improve dispersibility, the temperature during melt kneading is lowered. Various methods for applying a strong shear force by increasing the material viscosity have been applied. Among these, open-type open roll kneaders can be kneaded at a lower temperature than uniaxial and biaxial kneaders, and are used for the purpose of high dispersion of a release agent.
However, when a mixture containing a release agent and a resin is kneaded with an open roll kneader, there is a problem that the release agent dissolves before the resin, and the resin does not bite between the rolls by covering the roll surface. . This problem becomes more prominent as more release agent is added.

Japanese Patent Laid-Open No. 11-174730 (Japanese Patent No. 3403936) JP-A-8-305078 Japanese Patent No. 3603709 (Japanese Patent Laid-Open No. 2001-166530) JP 2007-3799 A Japanese Patent No. 3801458 (Japanese Patent Laid-Open No. 2002-296838) Japanese Patent No. 4049704 (Japanese Patent Laid-Open No. 2004-341129) Japanese Patent No. 4047758 (Japanese Patent Laid-Open No. 2004-325955)

  The present invention has been made in view of the above problems, and in a toner manufacturing method using an open roll kneader, a toner manufacturing method that can be finely dispersed in a binder resin even when a large amount of a release agent is added. Another object of the present invention is to provide a toner obtained by this manufacturing method and a process cartridge equipped with the toner.

  As a result of intensive studies, the present inventors have found that the above problems can be solved by the inventions described in the following [1] to [14], and have reached the present invention. Hereinafter, the present invention will be specifically described.

[1]: The above-described problems are at least a mixing step of mixing a toner raw material containing a binder resin and a release agent, a preheating step of raising the temperature of the mixture obtained in the mixing step, and the preheated mixture Obtained by the melt-kneading step, and a mixture supply step for supplying the mixture to the open roll kneader while maintaining the preheating temperature, and a melt-kneading step for melt-kneading the supplied pre-heated mixture with an open roll kneader. A method for producing a toner by pulverizing and classifying the melt-kneaded product to obtain a toner,
The binder resin may contain a plurality of resins having different softening temperatures, and the temperature rise in the preheating step is not less than the softening temperature Tm-20 (° C.) measured under the following conditions of the binder resin (Tm : When the binder resin is one kind, it is the softening temperature of itself, and when a plurality of resins having different softening temperatures are included, it corresponds to the lowest softening temperature).
The open roll kneader has two rolls (front roll and back roll) that can be heated and cooled respectively and the temperature of the front roll in the melt kneading step is higher than the temperature of the back roll. This is solved by the characteristic toner manufacturing method.
[Measurement conditions for softening temperature Tm]: When 1.0 g of a sample accommodated in a die having a diameter of 0.5 mm and a height of 1.0 mm flows out by a flow tester CFT-500 (manufactured by Shimadzu Corporation). Was set to Tm (heating rate: 3.0 ° C./min, preheating time: 3 minutes, load: 30 kg, measurement temperature range: 40 ° C. to 160 ° C.).

  [2]: The toner production method according to [1], wherein the temperature increase in the preliminary heating step is equal to or higher than the softening temperature Tm (° C.) of the binder resin.

  [3]: In the toner manufacturing method according to [1], the temperature increase temperature in the preliminary heating step is equal to or higher than the softening temperature Tm + 20 (° C.) of the binder resin.

  [4]: In the toner manufacturing method according to any one of [1] to [3], a discharge region is provided on at least one surface of the front roll and the back roll while stirring the mixture on the two rolls. It is characterized in that a groove that can be moved is provided.

  [5]: In the toner manufacturing method according to [4], the groove has a spiral shape.

  [6]: In the toner manufacturing method according to any one of [1] to [5], heating and cooling control of the front roll and the back roll is performed inside each roll by a heating and cooling medium. Features.

  [7]: In the toner production method according to any one of [1] to [6], the temperature of the heating / cooling medium in the front roll and the back roll in the melt-kneading step is a softening temperature of the binder resin, respectively. Tm-20 (° C.) or less (Tm: the softening temperature of the binder resin when it is one kind, and the lowest softening temperature when a plurality of resins having different softening temperatures (points) are included) It is characterized by that.

  [8]: In the toner production method according to any one of [1] to [7], each of the front roll and the back roll is melt-kneaded with the mixture supply side preliminarily heated at the center of the roll. It is characterized in that heat can be controlled by a heat medium / refrigerant at different temperatures in the two areas on the material discharge side.

  [9]: The toner production method according to [8], wherein the temperature of the heat medium / refrigerant on the melt kneaded product discharge side is lower than the temperature of the heat medium / refrigerant on the mixture supply side.

  [10]: The toner production method according to any one of [1] to [9], wherein each of the front roll and the back roll rotates at different peripheral speeds and is melt-kneaded.

  [11]: In the toner manufacturing method according to any one of [1] to [10], the binder resin is made of two types of resins having different softening temperatures.

  [12] The problem is solved by a toner produced by the method according to any one of [1] to [11].

  [13]: The above-described problems include a step of charging at least the surface of the photosensitive member by a charging unit, a step of forming an electrostatic latent image on the surface of the photosensitive member by an exposure unit, and a toner by a developing unit on the electrostatic latent image. An image forming method comprising: a step of attaching and developing as a toner image; a step of transferring the developed toner image to a recording medium by a transfer unit; and a step of fixing the transferred toner image by a fixing unit. The image forming method is characterized in that the toner attached to the electrostatic latent image by the developing means is the toner described in [12].

  [14]: The above-described problems include at least a photosensitive member, a charging unit that charges the surface of the photosensitive member, an exposure unit that exposes the charged surface of the photosensitive member to form an electrostatic latent image, and the formed electrostatic latent image. And a developing means for developing using toner, a transferring means for transferring the developed toner image to a recording medium, and a cleaning means for removing the toner remaining on the surface of the photosensitive member after transfer. This is solved by a process cartridge which can be attached to and detached from the image forming apparatus main body, and the toner used is the toner described in [12].

According to the toner manufacturing method of the present invention, a toner raw material mixture containing a binder resin and a release agent is preliminarily heated to a softening temperature Tm-20 (° C.) or higher of the binder resin, Cooling control and kneading part having two rolls (front roll and back roll) are supplied to an open roll kneader which is an open system, and the temperature of the front roll is controlled to be higher than the temperature of the back roll and melted. Since kneading, the time difference from the dissolution of the release agent to the dissolution of the resin is reduced, and the resin can bite between the rolls without covering the roll surface and the kneading can be performed well. It is possible to finely disperse the release agent uniformly in the binder resin, resulting in a toner with excellent separation and offset resistance for oilless fixing. .
According to the toner of the present invention, since it is excellent in separability and offset resistance as an oilless fixing toner, it can be applied to, for example, a heat roller fixing method with a simple apparatus configuration and easy handling. Therefore, it can be used for a low-end laser printer or the like that requires reduction in size and cost.
According to the image forming method of the present invention, since the toner image developed using the toner is transferred onto a recording medium by a transfer unit, the fixing method does not require an oil application mechanism (for example, a heat roller fixing method). However, there is no occurrence of an offset phenomenon and a stable image with high quality is formed.
According to the process cartridge of the present invention, since the toner is supplied from the developing unit, an abnormal image such as an offset phenomenon is generated even in a fixing method that does not require an oil application mechanism (for example, a heat roller fixing method). A stable image can be output. In addition, it is easy to store and transport, and can be exchanged in a short time.

As described above, the toner production method of the present invention includes at least a mixing step of mixing a toner raw material containing a binder resin and a release agent, a preheating step of raising the temperature of the mixture obtained in the mixing step, A mixture supplying step of supplying the heated mixture to an open roll kneader while maintaining the preheating temperature; and a melt kneading step of melt kneading the supplied preheated mixture with an open roll kneader, A toner production method in which the melt-kneaded product obtained in the step is pulverized and classified into a toner,
The binder resin may contain a plurality of resins having different softening temperatures, and the temperature rise in the preheating step is not less than the softening temperature Tm-20 (° C.) measured under the following conditions of the binder resin (Tm : When the binder resin is one kind, it is the softening temperature of itself, and when a plurality of resins having different softening temperatures are included, it corresponds to the lowest softening temperature).
The open roll kneader has two rolls (front roll and back roll) that can be heated and cooled respectively and the temperature of the front roll in the melt kneading step is higher than the temperature of the back roll. It is a feature.
[Measurement conditions for softening temperature Tm]: When 1.0 g of a sample accommodated in a die having a diameter of 0.5 mm and a height of 1.0 mm flows out by a flow tester CFT-500 (manufactured by Shimadzu Corporation). Was set to Tm (heating rate: 3.0 ° C./min, preheating time: 3 minutes, load: 30 kg, measurement temperature range: 40 ° C. to 160 ° C.).

That is, the toner production process in the present invention includes a mixing process, a preheating process, a mixture supplying process to an open roll kneader, and a melt kneading process using an open roll kneader, and the melt kneading process obtained in the melt kneading process. The product is pulverized and classified to obtain a toner. Below, each process is demonstrated.
As described above, the softening temperature Tm of the binder resin was obtained by weighing 1.0 g of a sample and using a flow tester CFT-500 (manufactured by Shimadzu Corporation) and a die having a diameter of 0.5 mm and a height of 1.0 mm. Measured in the range of 40 ° C. to 160 ° C. under the conditions of a heating rate of 3.0 ° C./min, a preheating time of 3 minutes, and a load of 30 kg, this is the temperature at which the sample flowed out 1/2.

<Mixing process>
In the toner manufacturing method of the present invention, first, in the mixing step, the binder resin, the release agent, and other toner raw materials selected as necessary are mixed. The mixing means is not particularly limited, and for example, a Henschel mixer can be used. The toner raw material mixture obtained in the mixing step is stored in a storage device (such as a hopper) and supplied to the preheating step.

<Preheating process>
Next, in the preheating step, the toner raw material mixture supplied from the storage device (such as a hopper) is heated by the temperature raising means to a softening temperature Tm-20 (° C.) or higher of the binder resin.
Here, the softening temperature Tm of the binder resin is the softening temperature of the binder resin when it is one kind, and the lowest softening temperature when it includes a plurality of resins having different softening temperatures. The method for raising the temperature of the toner raw material mixture by the temperature raising means is not particularly limited. You may combine the supply machine and heat source in the following mixture supply process, or you may use a well-known kneading machine for temperature rising.

<Mixture supply process>
The toner raw material mixture heated to Tm−20 (° C.) or higher in advance is supplied to the next open roll kneader while maintaining the preheating temperature. As a mixture supply means, a preheating process and a mixture supply process may be performed simultaneously. For example, it can be supplied to the open roll kneader while adjusting the temperature of the mixture by a screw provided with a heater capable of heating control. The mixture is fed to the vicinity between the front roll and the back roll.

<Melting and kneading process>
As described above, the kneader used in the present invention is an open roll kneader in which the kneading part is an open system, and each of the two rolls that can be heated and cooled and rotated, that is, a front roll and a back roll. Have.
In the open roll kneader, the temperature of the front roll is controlled to be higher than the temperature of the back roll, so that the toner raw material mixture preheated to the softening temperature Tm-20 (° C.) or higher of the binder resin is the open roll. When supplied to the kneader, the time difference from the dissolution of the release agent to the dissolution of the resin is reduced, so that only the release agent dissolves first and does not cover the roll surface. The release agent can be finely dispersed evenly. Of course, additives such as a colorant and a charge control agent which are added if necessary are also kneaded well. In addition, by adjusting the temperature of the front roll higher than the temperature of the back roll, the kneaded material can be attached only to the front roll, and good melt-kneading is performed.
Furthermore, if the toner raw material mixture is preheated to an open roll kneader at a softening temperature Tm ° C. or higher of the binder resin, the time difference from the dissolution of the release agent to the dissolution of the resin becomes smaller. Can be kneaded without covering the roll surface, so that the release agent can be further finely dispersed. Further, if the preheating of the toner raw material mixture is set to Tm ° C. + 20 ° C. or higher and supplied to the open roll kneader, the release agent can be finely dispersed in a more preferable state.
Heating and cooling control of the front roll and the back roll is performed by a heating / cooling medium inside each roll. That is, a heating medium or refrigerant flows in the roll, and the temperature of the roll is adjusted.

In the present invention, each of the front roll and the back roll in the melt-kneading step has different temperatures in two regions (two zones) on the mixture supply side and the melt-kneaded product discharge side that are preheated with the central portion of the roll as a boundary. It is desirable that heat control is possible.
That is, it is possible to further finely disperse the release agent by setting the supply side to a temperature at which the kneaded material can be fused on the roll and lowering the discharge side temperature that greatly contributes to the dispersion of the release agent.

  Moreover, it is desirable that the temperature of the heating / cooling medium in the front roll and the back roll in the melt-kneading step is not more than the softening temperature Tm-20 (° C.) of the binder resin. Note that (Tm is the same as defined above). By setting the temperature of the heating medium in the front roll to be equal to or lower than the softening temperature Tm-20 (° C.) of the binder resin, the viscosity of the kneaded product can be increased and a strong shearing force can be given. Therefore, it becomes possible to further finely disperse the release agent. Furthermore, it is preferable to lower the roll temperature on the discharge side than on the supply side.

  It is desirable to provide a groove on the surface of at least one of the front roll and the back roll so that the mixture on the two rolls can be moved to the discharge region while stirring. By this groove, the mixture (toner pool: bank) supplied to the two rolls and collected between the front roll and the back roll is efficiently stirred, and the kneading is further uniformly dispersed by the kneading. The goods move from the roll supply side to the discharge area. A spiral shape is one of the preferred forms for the groove.

  Furthermore, each of the front roll and the back roll is preferably melt-kneaded while rotating at different peripheral speeds. By rotating the rolls at different peripheral speeds, a shearing force in the gap between the rolls can be strongly applied, and the release agent can be more finely dispersed.

The present invention will be further described with reference to the drawings.
FIG. 1 is a schematic top view schematically showing a melt-kneading step using an open roll kneader in the toner production method of the present invention.
In FIG. 1, a toner raw material mixture (substantially “mixture”) mixed by a Henschel mixer (not shown) is stored in a hopper (1). The mixture stored in the hopper (1) is supplied between the front roll (3) and the back roll (4) by the screw (2). At this time, the outer wall of the screw is heated by a temperature raising means (heater), and the temperature of the mixture is adjusted to a predetermined temperature and the temperature is raised (the preheating step and the mixture supplying step are performed simultaneously).
In the present invention, the preheating temperature of the mixture at the time of supply is not lower than the softening temperature Tm-20 (° C.) of the binder resin, more preferably not lower than the softening temperature Tm ° C. of the binder resin, more preferably softening temperature Tm ° C. of the binder resin. + 20 ° C or higher.

A heating medium or a refrigerant flows through the front roll (3) and the back roll (4), respectively, and the temperature of the roll can be adjusted. The temperature of the front roll (3) is controlled to be higher than the temperature of the back roll (4). By adjusting the temperature of the front roll (3) higher than that of the back roll (4), the kneaded material can be attached only to the front roll. Since the temperature of the kneaded product is greatly influenced by the temperature of the front roll, the temperature of the front roll (3) is lower than the softening temperature Tm-20 (° C.) of the binder resin in order to reduce the viscosity of the kneaded product and increase the shearing force. It is preferable to lower the temperature on the discharge side from the supply side. In addition, since a toner reservoir (bank) is formed between the front roll (3) and the back roll (4), it is preferable to use a roll having a groove on the surface for the purpose of stirring it. Further, by installing the partition plate (5) on the left side in FIG. 1 from the position where the mixture on the two rolls is supplied, the melt-kneaded product moves to the discharge side (the scraper (7) side in FIG. 1). . A cutter (6) and a scraper (7) are brought into contact with the melt kneaded material discharge part on the front roll (3) side, and the molten kneaded material that has moved is separated and collected.
The melt-kneaded product obtained in the melt-kneading step is cooled, pulverized (pulverizing step), and classified into particles of a predetermined size (classifying step). Inorganic fine particles and resin fine particles can be externally added to the outer surface of the classified particles (toner base).

  That is, according to the toner manufacturing method of the present invention, even if a large amount of a release agent is added, it can be finely dispersed in the binder resin, and the occurrence of an offset phenomenon or the like is suppressed even in the image formation of the heat roller fixing method. . The toner of the present invention can also be applied to low-end laser printers (copiers, fax machines, etc.), and can be reduced in size and cost.

  The toner raw material in the toner production method of the present invention contains at least a binder resin and a release agent, and a colorant, a charge control agent, inorganic fine particles, and the like can be used depending on the purpose. Hereinafter, the toner raw material will be described.

<Binder resin>
The type of binder resin is not particularly limited, and binder resins known in the field of full-color toners such as polyester resins, (meth) acrylic resins, styrene- (meth) acrylic copolymer resins, epoxy resins, COC [Cyclic olefin resin (for example, TOPAS-COC: manufactured by Ticona)] or the like may be used, but a polyester resin is preferably used from the viewpoint of stress resistance in the developing device.
As the polyester resin preferably used in the present invention, a polyester resin obtained by polycondensation of a polyhydric alcohol component and a polyvalent carboxylic acid component can be used.

  Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2- Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2,0) -2,2-bis (4-hydroxyphenyl) propane Bisphenol A alkylene oxide adducts such as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanedio , 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, and the like.

  Examples of the trihydric or higher alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol. 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3,5-trihydroxymethylbenzene, etc. Is mentioned.

  Examples of the divalent carboxylic acid component among the polyvalent carboxylic acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and succinic acid. , Adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenyl succinic acid, isododecenyl succinic acid, n-dodecyl succinic acid, isododecyl succinic acid, n-octenyl succinic acid, isooctenyl succinic acid, n-octyl succinic acid , Isooctyl succinic acid, anhydrides or lower alkyl esters of these acids.

  Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2 , 4-Naphthalenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4- Examples include cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,7,8-octanetetracarboxylic acid, pyromellitic acid, empole trimer acid, anhydrides of these acids, and lower alkyl esters.

  In the present invention, as a polyester resin, a polyester resin raw material monomer, a vinyl resin raw material monomer, and a mixture of monomers that react with both resin raw material monomers are used to obtain a polyester resin in the same container. A resin obtained by performing a condensation polymerization reaction and a radical polymerization reaction for obtaining a vinyl resin in parallel (hereinafter, simply referred to as “vinyl polyester resin”) can also be suitably used. In addition, the monomer which reacts with the raw material monomers of both resins is, in other words, a monomer that can be used for both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxyl group capable of condensation polymerization and a vinyl group capable of radical polymerization, and examples thereof include fumaric acid, maleic acid, acrylic acid, and methacrylic acid.

Examples of the raw material monomer for the polyester resin include the polyhydric alcohol component and the polyvalent carboxylic acid component described above. Examples of the raw material monomer for the vinyl resin include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-tert- Styrene or styrene derivatives such as butylstyrene and p-chlorostyrene; Ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; methyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate , Isobutyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, 3- (methyl) butyl methacrylate, hexyl methacrylate, octyl methacrylate, nonyl methacrylate Methacrylic acid alkyl esters such as decyl methacrylate, undecyl methacrylate, dodecyl methacrylate; methyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, acrylic Alkyl acrylates such as n-pentyl acid, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, undecyl acrylate, and dodecyl acrylate Esters; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, maleic acid; acrylonitrile, maleic acid ester, itaconic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinylmethyl Examples include ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether.
As a polymerization initiator when polymerizing the raw material monomer of the vinyl resin, for example, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobisisobutyronitrile, 1,1 Azo or diazo polymerization initiators such as' -azobis (cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, benzoyl peroxide, dicumyl peroxide, And peroxide polymerization initiators such as methyl ethyl ketone peroxide, isopropyl peroxycarbonate, lauroyl peroxide, and the like.

As the binder resin, various polyester resins as described above are preferably used. Among them, from the viewpoint of further improving the separability and offset resistance as an oilless fixing toner, It is more preferable to use 1 binder resin and 2nd binder resin).
A more preferred first binder resin is a polyester resin obtained by polycondensation of the above-mentioned polyhydric alcohol component and polyhydric carboxylic acid component, in particular, a bisphenol A alkylene oxide adduct as the polyhydric alcohol component. It is a polyester resin obtained using terephthalic acid and fumaric acid as components.
More preferred second binder resins are vinyl polyester resins, especially bisphenol A alkylene oxide adduct, terephthalic acid, trimellitic acid and succinic acid as raw material monomers for polyester resins, and styrene and butyl acrylate as raw material monomers for vinyl resins. And a vinyl-based polyester resin obtained using fumaric acid as a bireactive monomer.

<Release agent>
The type of the release agent is not particularly limited, and a release agent known in the field of full color toners can be used. In general, the lower the polarity of the release agent, the better the releasability with the fixing member roller. Therefore, a hydrocarbon wax having a low polarity is preferable.

<Hydrocarbon wax>
The hydrocarbon wax is a wax composed of only carbon atoms and hydrogen atoms, and does not contain an ester group, an alcohol group, an amide group, or the like. Specific hydrocarbon waxes include polyolefin waxes such as polyethylene, polypropylene, copolymers of ethylene and propylene, petroleum waxes such as paraffin wax and microcrystalline wax, and synthetic waxes such as Fischer-Tropsch wax. . Among these, polyethylene wax, paraffin wax, and Fischer-Tropsch wax are preferable in the present invention, and polyethylene wax and paraffin wax are more preferable.

<Melting point of release agent>
The melting point of the release agent (for example, wax) in the present invention is the endothermic peak of the wax at the time of temperature rise measured by a differential scanning calorimeter (DSC).
The melting point of the release agent is preferably in the range of 70 ° C to 90 ° C. If it is higher than 90 ° C., the melting of the wax in the fixing process becomes insufficient, and the separation from the fixing member cannot be ensured. On the other hand, if the temperature is lower than 70 ° C., there is a problem in storage stability such that toner particles are fused with each other in a high temperature and high humidity environment. In order to provide a sufficient margin for fixing separation at a low temperature, the melting point of the wax is more preferably from 70 ° C to 85 ° C, and further preferably from 70 ° C to 80 ° C.

<Colorant>
In the toner of the present invention, a known colorant conventionally used in full color toners may be used. For example, carbon black, aniline blue, calcoil blue, chrome yellow, ultramarine blue, duPont oil red, quinoline yellow, methylene blue chloride, copper phthalocyanine, malachite green oxalate, lamp black, rose bengal, C.I. I. Pigment red 48: 1, C.I. I. Pigment red 122, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 184, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 74, C.I. I. Solvent Yellow 162, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment blue 15: 1, C.I. I. And CI Pigment Blue 15: 3.

  The content of the colorant in the toner particles is preferably in the range of 2 to 15 parts by weight with respect to 100 parts by weight of the total binder resin. It is preferable from the viewpoint of dispersibility that the colorant is used in the form of a masterbatch dispersed in a mixed binder resin of the first binder resin and the second binder resin used. The addition amount of the masterbatch may be an amount such that the amount of the colorant contained is within the above range. The colorant content in the masterbatch is preferably 20 to 40% by weight.

<Charge control agent>
In the toner of the present invention, a known charge control agent conventionally used in full color toners may be used.
For example, nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (including fluorine-modified quaternary ammonium salts), alkylamides, phosphorus Simple substance or compound, tungsten simple substance or compound, fluorine-based activator, salicylic acid metal salt, metal salt of salicylic acid derivative, and the like.

  Specifically, Bontron 03 of nigrosine dye, Bontron P-51 of quaternary ammonium salt, Bontron S-34 of metal-containing azo dye, E-82 of oxynaphthoic acid metal complex, E- of salicylic acid metal complex 84, E-89 of a phenol-based condensate (above, manufactured by Orient Chemical Co., Ltd.), TP-302, TP-415 of a quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium salt Copy charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) ), Copper phthalocyanine, perylene, quinacridone, a Zeo pigments and other polymer compounds having functional groups such as sulfonic acid groups, carboxyl groups, and quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

<Inorganic fine particles>
In the present invention, inorganic fine particles can be used to assist fluidity and developability.
Specific examples of the inorganic fine particles include, for example, silicon oxide, zinc oxide, tin oxide, silica sand, titanium oxide, clay, mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide. , Zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like.

In the toner manufacturing method of the present invention, as described above, the melt-kneaded product obtained in the melt-kneading step is cooled, pulverized (pulverizing step), and classified into particles of a predetermined size (classifying step).
As for the pulverization, for example, coarse pulverization using a hammer mill, a rotoplex or the like, and further, a fine pulverizer using a jet stream or a mechanical pulverizer can be used. Further, the volume average particle diameter of the pulverized product is adjusted by a rotor type classifier or a wind classifier.
Inorganic fine particles and resin fine particles can be externally added to the outer surface of the classified particles (toner base). For the external addition of the external additive to the toner base, for example, the toner base and the external additive are mixed and stirred using a mixer to coat the toner surface while the external additive is being crushed. At this time, it is important in terms of durability that external additives such as inorganic fine particles and resin fine particles are uniformly and firmly attached to the toner base.

The toner obtained by the toner manufacturing method of the present invention can be used by being mounted on a process cartridge.
That is, at least the photosensitive member, a charging unit that charges the surface of the photosensitive member, an exposure unit that exposes the charged surface of the photosensitive member to form an electrostatic latent image, and toner is used for the formed electrostatic latent image. Image forming apparatus main body integrated with developing means for developing, transfer means for transferring the developed toner image to a recording medium, and one means selected from cleaning means for removing toner remaining on the surface of the photoreceptor after transfer It can be mounted as a toner used in a process cartridge that is detachable from the printer.

  There are many shapes and the like of the process cartridge, but a general example is shown in FIG. That is, FIG. 2 is a schematic cross-sectional view showing a configuration example of the process cartridge according to the present invention. In the periphery of the photoconductor 11, a charging device 12 as a charging means, an exposure device 13 as an exposure means, and a development as a developing means. An apparatus 14, a transfer device 16 that is a transfer means, a cleaning device 17 that is a cleaning means, and a charge removal device 1A that is a charge removal means are provided. In this case, the toner of the present invention is mounted on the developing device 14. Reference numeral 18 denotes an image receiving medium (for example, paper). The photoreceptor (11) has a drum shape, but may be a sheet or an endless belt. Reference numeral 19 denotes fixing means.

  If the toner of the present invention is installed, even in a fixing method that does not require an oil application mechanism (for example, a heat roller fixing method), an image having a stable quality can be output without occurrence of an offset phenomenon. In addition, the process cartridge according to the present invention is detachable from the image forming apparatus main body, and can be easily stored, transported, etc., the process means can be easily replaced in a short time, and the handling convenience is high and maintenance is possible. Easy. In addition, since the photosensitive member and each process means are integrated, and the relative positional accuracy is high, the image quality can be improved, and an image with good quality can be formed even in the long-term repeated sheet passing.

  An image forming method using the toner obtained by the toner production method of the present invention, that is, a step of charging at least the surface of the photoreceptor with a charging unit, and a step of forming an electrostatic latent image on the surface of the photoreceptor with an exposing unit. A step of developing a toner image by attaching toner to the electrostatic latent image by a developing unit, a step of transferring the developed toner image to a recording medium by a transfer unit, and a fixing unit of the transferred toner image. If the toner of the present invention is used in an image forming method including a fixing step, an offset phenomenon does not occur even in a fixing method that does not require an oil application mechanism (for example, a heat roller fixing method). , An image of good quality is stably formed.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not restrict | limited by these Examples.

Example 1
Paraffin wax (melting point 73 ° C.) with respect to 100 parts by mass of the binder resin (polyester resin; softening temperature Tm 142 ° C.) 50 parts by mass and the second binder resin (polyester resin; softening temperature Tm 112 ° C.) 50 parts by mass. ) And 1.0 part by mass of a boron-based charge control agent were mixed with a henschol mixer.
The above mixture is heated to 95 ° C. with a screw feeder equipped with a heat source, and while maintaining the temperature, it has two rolls (front roll and back roll) that can be heated and cooled and rotated. Is supplied to an open roll kneader with a roll diameter of 150 mm at 10 kg / h, the front roll heat medium is controlled to 120 ° C. and the back roll heat medium is controlled to 20 ° C. And kneaded.
The kneaded product is roughly crushed with a crusher feather mill (manufactured by Hosokawa Micron Corporation) and then pulverized with a jet crusher IDS (manufactured by Nippon Pneumatic Industry Co., Ltd.), and a rotor type classifier (teaplex type classifier type: 100 ATP: And a toner having a volume average diameter of 8.2 μm was obtained.
The dispersion diameter of the release agent in the obtained toner was measured based on the following “Method for evaluating dispersion diameter of release agent”, and the dispersion diameter was 1.27 μm.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Example 1.

<Method for evaluating dispersion diameter of release agent>
In the present invention, the number distribution (average dispersed particle size + 3σ) was calculated and used as the dispersion size of the release agent. Specifically, the toner was embedded in an epoxy resin, cut into an ultrathin section of about 100 μm, and stained with ruthenium tetroxide, and observed with a transmission electron microscope (TEM) at a magnification of 10,000 times. 100 average particle diameters of individual release agents are randomly observed from an image obtained by photographing, and the distribution of the dispersed particle diameters of the release agents in the unit of 0.05 μm width of the number distribution ratio of the particle diameters. It was.

(Example 2)
Paraffin wax (melting point 73 ° C.) with respect to 100 parts by mass of the binder resin (polyester resin; softening temperature Tm 142 ° C.) 50 parts by mass and the second binder resin (polyester resin; softening temperature Tm 112 ° C.) 50 parts by mass. ) And 1.0 part by mass of a boron-based charge control agent were mixed with a henschol mixer.
The above mixture is heated to 114 ° C. with a screw feeder equipped with a heat source, and while maintaining the temperature, it has heating and cooling control and two rolls (front roll and back roll) that can be rotated, and each roll diameter. Is supplied to a 150 mm open roll kneader at 10 kg / h, the front roll heat medium is 120 ° C., the back roll heat medium is 20 ° C., both rolls are rotated at a peripheral speed of 0.39 m / sec, and kneaded. Went. Thereafter, the same treatment as in Example 1 was performed to obtain a toner having a volume average diameter of 8.1 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 1.02 μm.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Example 2.

(Example 3)
Paraffin wax (melting point 73 ° C.) with respect to 100 parts by mass of the binder resin (polyester resin; softening temperature Tm 142 ° C.) 50 parts by mass and the second binder resin (polyester resin; softening temperature Tm 112 ° C.) 50 parts by mass. ) And 1.0 part by mass of a boron-based charge control agent were mixed with a henschol mixer.
The above mixture is heated to 133 ° C. with a screw feeder equipped with a heat source, and while maintaining the temperature, it has two rolls (front roll and back roll) that can be heated and cooled, and each roll diameter. Is supplied to a 150 mm open roll kneader at 10 kg / h, the front roll heat medium is 120 ° C., the back roll heat medium is 20 ° C., both rolls are rotated at a peripheral speed of 0.39 m / sec, and kneaded. Went. Thereafter, the same treatment as in Example 1 was performed to obtain a toner having a volume average diameter of 8.2 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 0.85 μm.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Example 3.

Example 4
In place of the roll of the open roll kneader used in Example 1, a groove is engraved on the roll (having a spiral groove that allows the molten kneaded product to move to a discharge area on the roll) Kneading was performed in the same manner as in Example 1 except that it was used. Thereafter, the same treatment as in Example 1 was performed to obtain a toner having a volume average diameter of 8.2 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 0.71 μm.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Example 4.

(Example 5)
Kneading was performed in the same manner as in Example 4 except that the heat medium temperature of the front roll of the open roll kneader used in Example 1 was changed from 120 ° C to 90 ° C. Thereafter, the same treatment as in Example 4 was performed to obtain a toner having a volume average diameter of 8.0 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 0.65 μm.
Table 1 below summarizes the main toner production conditions and the dispersion diameter evaluation results of Example 5.

(Example 6)
In Example 4, the heat medium temperature on the supply side of the front roll is 90 ° C., the heat medium temperature on the discharge side is 60 ° C., the heat medium temperature on the back roll supply side is 30 ° C., and the heat medium temperature on the discharge side is 20 ° C. Kneading was performed in the same manner as in Example 4 except that. Thereafter, the same treatment as in Example 4 was performed to obtain a toner having a volume average diameter of 8.1 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 0.38 μm.
Table 1 below summarizes the main toner production conditions and the dispersion diameter evaluation results of Example 6.

(Example 7)
In Example 6, kneading was performed in the same manner as in Example 6 except that the peripheral speed of the front roll was rotated at 0.39 m / s and the peripheral speed of the back roll was rotated at 0.31 m / s. Thereafter, the same treatment as in Example 4 was performed to obtain a toner having a volume average diameter of 8.0 μm. When the dispersion diameter of the release agent was measured in the same manner as in Example 1, the dispersion diameter of the release agent in the obtained toner was 0.29 μm.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Example 7.

(Comparative Example 1)
Paraffin wax (melting point 73 ° C.) with respect to 100 parts by mass of the binder resin (polyester resin; softening temperature Tm 142 ° C.) 50 parts by mass and the second binder resin (polyester resin; softening temperature Tm 112 ° C.) 50 parts by mass. ) And 1.0 part by mass of a boron-based charge control agent were mixed with a henschol mixer.
The above mixture is heated to 90 ° C. with a screw feeder equipped with a heat source, and while maintaining the temperature, it has two rolls (front roll and back roll) that can be heated and cooled and rotated, and each roll diameter Was supplied to a 150 mm open roll kneader at 10 kg / h. Both rolls were rotated at a peripheral speed of 0.39 m / sec and kneaded.
However, the paraffin wax dissolved before the binder resin covered the roll surface, and the mixture supplied later did not bite between the rolls.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Comparative Example 1.

(Comparative Example 2)
Paraffin wax (melting point 73 ° C.) with respect to 100 parts by mass of the binder resin (polyester resin; softening temperature Tm 142 ° C.) 50 parts by mass and the second binder resin (polyester resin; softening temperature Tm 112 ° C.) 50 parts by mass. ) And 1.0 part by mass of a boron-based charge control agent were mixed with a henschol mixer.
The mixture is heated to 100 ° C. with a screw feeder equipped with a heat source, then cooled to 90 ° C., and has two rolls (front roll and back roll) that can be heated and cooled and rotated. It supplied at 10 kg / h to the open roll kneader with a diameter of 150 mm. Both rolls were rotated at a peripheral speed of 0.39 m / sec and kneaded.
However, the paraffin wax dissolved before the binder resin covered the roll surface, and the mixture supplied later did not bite between the rolls.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Comparative Example 2.

(Comparative Example 3)
In Example 1, kneading was carried out in the same manner as in Example 1 except that the temperature of the heat medium of the front roll and that of the back roll were controlled to be the same (120 ° C.). As a result, it was wound around both the front roll and the back roll and could not be cut at the discharge section.
Table 1 below summarizes the main toner production conditions and dispersion diameter evaluation results of Comparative Example 3.

The following can be seen from the evaluation results in Table 1 above.
Since the toner raw material mixture is preheated to a softening temperature Tm-20 (° C.) or higher of the binder resin and supplied to an open roll kneader, the release agent can be kneaded without covering the roll surface. It becomes possible to finely disperse the release agent. Further, if the temperature is equal to or higher than the softening temperature Tm (° C.) of the binder resin, it can be further finely dispersed, and if the softening temperature of the binder resin is Tm + 20 (° C.), it can be further finely dispersed.
Further, if grooves are provided on the roll surface, the release agent can be further finely dispersed.
Furthermore, if the temperature of the heating / cooling medium in the front roll and the back roll is not higher than the softening temperature Tm-20 (° C.) of the binder resin, respectively, the viscosity of the kneaded product can be increased to give a strong shearing force. Thus, the release agent can be finely dispersed.
In addition, each of the front roll and the back roll has different temperatures in two regions of the mixture supply side and the melt kneaded product discharge side preheated from the center of the roll, that is, the supply side has the kneaded material on the roll. The release agent can be finely dispersed by lowering the temperature on the discharge side, which greatly contributes to the dispersion of the release agent, at a temperature that can be fused.
Moreover, if each of the front roll and the back roll rotates at different peripheral speeds and is melt-kneaded, a shearing force in the gap between the rolls can be strongly applied, and the release agent can be finely dispersed.
The toner obtained by the toner manufacturing method of the present invention is excellent in separability and offset resistance as an oil-less fixing toner, and is therefore applied to a fixing method that does not require an oil application mechanism (for example, a heat roller fixing method). Is possible. By using such a toner, there is no occurrence of an offset phenomenon and a stable image with high quality is formed. If mounted on a process cartridge, a stable image can be output without occurrence of an abnormal image such as an offset phenomenon.

FIG. 3 is a schematic top view schematically showing a melt-kneading step using an open roll kneader in the toner production method of the present invention. It is a schematic sectional drawing which shows the structural example of the process cartridge which concerns on this invention.

Explanation of symbols

(Reference in FIG. 1)
1 Hopper 2 Screw 3 Front roll 4 Back roll 5 Partition plate 6 Cutter 7 Scraper (reference numeral in FIG. 2)
DESCRIPTION OF SYMBOLS 1A Static elimination apparatus 11 Photoconductor 12 Charging apparatus 13 Exposure apparatus 14 Developing apparatus 16 Transfer apparatus 17 Cleaning apparatus 18 Image receiving medium

Claims (14)

At least a mixing step of mixing a toner raw material containing a binder resin and a release agent, a preheating step of raising the temperature of the mixture obtained in the mixing step, and maintaining the preheating temperature of the preheated mixture A mixture supply step to be supplied to the open roll kneader as it is, and a melt kneading step in which the supplied preheated mixture is melt kneaded with an open roll kneader, and the melt kneaded product obtained in the melt kneading step is pulverized and classified A toner manufacturing method for producing toner,
The binder resin may contain a plurality of resins having different softening temperatures, and the temperature rise in the preheating step is not less than the softening temperature Tm-20 (° C.) measured under the following conditions of the binder resin (Tm : When the binder resin is one kind, it is the softening temperature of itself, and when a plurality of resins having different softening temperatures are included, it corresponds to the lowest softening temperature).
The open roll kneader has two rolls (front roll and back roll) that can be heated and cooled respectively and the temperature of the front roll in the melt kneading step is higher than the temperature of the back roll. A toner production method.
[Measurement conditions for softening temperature Tm]: When 1.0 g of a sample accommodated in a die having a diameter of 0.5 mm and a height of 1.0 mm flows out by a flow tester CFT-500 (manufactured by Shimadzu Corporation). Was set to Tm (heating rate: 3.0 ° C./min, preheating time: 3 minutes, load: 30 kg, measurement temperature range: 40 ° C. to 160 ° C.).   The toner manufacturing method according to claim 1, wherein a temperature increase temperature in the preheating step is equal to or higher than a softening temperature Tm (° C.) of the binder resin.   The toner manufacturing method according to claim 1, wherein a temperature increase temperature in the preheating step is equal to or higher than a softening temperature Tm + 20 (° C.) of the binder resin.   The groove | channel which makes it possible to move to the discharge | emission area | region, stirring the mixture on the said 2 rolls in the surface of at least one of the said front roll and a back roll is provided. The toner manufacturing method as described.   The toner manufacturing method according to claim 4, wherein the groove has a spiral shape.   6. The toner manufacturing method according to claim 1, wherein heating / cooling control of the front roll and the back roll is performed inside each roll by a heating / cooling medium.   The temperature of the heating / cooling medium in the front roll and the back roll in the melt-kneading step is less than or equal to the softening temperature Tm-20 (° C.) of the binder resin (Tm: the softening temperature of the binder resin when one kind is used) The toner production method according to claim 1, wherein the toner production method corresponds to the lowest softening temperature when a plurality of resins having different softening temperatures (points) are included.   Each of the front roll and the back roll can be controlled by a heat medium / refrigerant at different temperatures in the two regions of the mixture supply side and the melt-kneaded product discharge side preheated from the center of the roll. The toner manufacturing method according to claim 1, wherein:   The toner manufacturing method according to claim 8, wherein a temperature of the heat medium / refrigerant on the melt kneaded product discharge side is lower than a temperature of the heat medium / refrigerant on the mixture supply side.   The toner production method according to claim 1, wherein each of the front roll and the back roll is melt-kneaded while rotating at different peripheral speeds.   The toner manufacturing method according to claim 1, wherein the binder resin is made of two types of resins having different softening temperatures.   A toner produced by the method according to claim 1.   At least the surface of the photosensitive member is charged by a charging unit, the step of forming an electrostatic latent image on the surface of the photosensitive member by an exposing unit, and the toner is attached to the electrostatic latent image by a developing unit and developed as a toner image. An image forming method comprising: a step of transferring the developed toner image onto a recording medium by a transfer unit; and a step of fixing the transferred toner image by a fixing unit. The image forming method, wherein the toner attached to the electrostatic latent image is the toner according to claim 12.   At least the photosensitive member, a charging unit for charging the surface of the photosensitive member, an exposure unit for exposing the charged surface of the photosensitive member to form an electrostatic latent image, and developing the formed electrostatic latent image using toner. An image forming apparatus main body integrated with a developing means, a transferring means for transferring the developed toner image to a recording medium, and a cleaning means for removing toner remaining on the surface of the photosensitive member after transfer. A process cartridge capable of being used, wherein the toner used is the toner according to claim 12.

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