JP2017003698A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that can suppress stacked sheets from being adhered to each other, the sheets each having an image thermally fixed thereto with toner.SOLUTION: An image forming apparatus 1 is an image forming apparatus that comprises: an image forming part that transfers a toner containing at least a binder resin and mold release agent onto a sheet to form an image; and a fixing device that applies heat and pressure to the sheet to which the image is transferred to fix the image, the image forming apparatus including a fine particle dispersion liquid application unit B that applies a fine particle dispersion liquid to the image fixed by the fixing device.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus. More specifically, the present invention relates to an image forming apparatus having an image in which toner is thermally fixed and capable of suppressing sticking of stacked sheets.

  2. Description of the Related Art Conventionally, in an electrophotographic image forming method for forming a visible image by electrophotography, a toner image formed by an electrostatic latent image developing toner (hereinafter also simply referred to as “toner”) on a transfer medium such as paper is used. As a fixing method, a heat roller fixing system in which a transfer medium on which a toner image is formed is fixed by passing between a heating roller and a pressure roller is widely used.

  In order to ensure the fixability in this heat roller fixing system, that is, the adhesion of the toner to the transfer medium such as paper, the heating roller needs a high heat capacity.

In recent years, there has been a growing demand for energy saving for electrophotographic image forming apparatuses from the viewpoint of global warming prevention measures.
For this reason, in particular, in an electrophotographic image forming apparatus employing a heat roller fixing method, a technique for reducing the amount of heat required for fixing a toner image, that is, a technique for lowering the fixing temperature has been studied.

On the other hand, in an electrophotographic system, it is possible to transfer a toner image from a photosensitive member onto a belt or paper by using a charge having a polarity opposite to that of toner.
That is, the toner is electrically pulled by applying a transfer potential opposite to the toner from the back side of the object to be transferred, and at that time, a transfer current is injected onto the transfer belt or paper that is the object to be transferred. Is done. Usually, a material having a high electrical resistance such as paper or toner is liable to leak electric charges as the temperature increases.
That is, in the image forming process in which low temperature fixing has been promoted, the charge accumulated on the paper is less likely to be released by the transfer current, and as a result, the printed image is discharged in a charged state.

As a result of the progress of low-temperature fixing at present, it is difficult to release the applied potential, and as a result, the sticking of the printed matter due to the accumulated charge has become apparent.
Therefore, a technique that does not cause sticking between images even in a low-temperature fixing process has been desired.

Japanese Patent Application Laid-Open No. H10-228561 proposes a system for removing a static image by temporarily storing a fixed image in an intermediate tray provided with a plurality of holes.
This is temporarily accommodated in an intermediate tray having a large number of holes on the bottom surface, thereby reducing the contact area between the paper and the intermediate tray and preventing sticking.
Patent Document 2 proposes a system for discharging static electricity by alternately discharging static eliminating sheets from a fixed image.
However, in these systems, the process becomes complicated, and the productivity is lowered in any case.

Therefore, Patent Document 3 proposes a system that improves the printing speed by quickly cooling an image immediately after fixing by installing a blower.
In this system, it is possible to suppress sticking between fixed images caused by stacking of fixed images in a state where toner is not completely solidified immediately after fixing, but it is not possible to suppress sticking caused by static electricity.

  Patent Document 4 proposes a system for discharging static electricity by spraying negative ions on a fixed image. However, it is impossible to completely remove the electric charge held in the fixed image only by spraying negative ions.

  Accordingly, there is an urgent need to develop a system that suppresses sticking of fixed images without reducing productivity.

JP 11-223964 A JP2013-213894A JP 2014-40326 A JP 2006-343491 A

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus having an image in which toner is thermally fixed and capable of suppressing sticking of stacked sheets. It is.

In order to solve the above problems, the present inventor, in the process of examining the cause of the above problems, by applying a fine particle dispersion to the image fixed by the fixing device, the fine particles exhibit a spacer effect, As a result, it was found that the printed materials can be prevented from sticking to each other due to electrostatic force, and the present invention has been achieved.
That is, the said subject which concerns on this invention is solved by the following means.

1. An image forming unit that forms an image by transferring toner containing at least a binder resin and a release agent onto a sheet, and a fixing device that fixes the image by heating and pressing the sheet on which the image is transferred An image forming apparatus having
An image forming apparatus comprising: a fine particle dispersion applying unit for applying a fine particle dispersion to the image fixed by the fixing device.

2. 2. The image forming apparatus according to claim 1, wherein the specific gravity of the fine particles contained in the fine particle dispersion is in the range of 0.90 to 2.0 g / cm ³ .

3. ^3. The image forming apparatus according to item 1 or 2, wherein the specific gravity of the fine particles contained in the fine particle dispersion is in the range of 0.90 to 1.2 g / cm ³ .

  4). Any one of Items 1 to 3, wherein the fine particles contained in the fine particle dispersion contain polystyrene resin, acrylic resin, methacrylic resin, urea resin, silicone resin or epoxy resin. The image forming apparatus described in the item.

5. 5. The image forming apparatus according to claim 1, wherein a median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is in a range of 10 to ₅₀ μm. .

6). 6. The image forming apparatus according to claim 1, wherein a median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is in a range of 15 to 30 μm. .

7). The fine particle dispersion applying unit has a humidifying roller for applying a humidifying liquid to the paper and a means for supplying the humidifying liquid to the humidifying roller;
The image forming apparatus according to any one of Items 1 to 6, wherein the humidifying liquid is the fine particle dispersion.

8). The fine particle dispersion application unit has a vertical paper conveyance path for guiding the paper downward or upward, a liquid supply unit, a liquid supply roller to which the humidifying liquid is supplied from the liquid supply unit,
The image forming apparatus according to claim 7, wherein the humidifying roller receives the humidifying liquid from the liquid supply roller.

  9. The image forming apparatus according to any one of Items 1 to 8, wherein the fine particle dispersion contains a surfactant.

10. The fine particle dispersion applied to one surface of the paper on which the image has been fixed is a dispersion in which a cationic surfactant is dispersed;
Any one of Items 1 to 9, wherein the fine particle dispersion applied to the surface opposite to the one surface is a dispersion dispersed with an anionic surfactant. The image forming apparatus described in 1.

  11. The image forming apparatus according to any one of Items 1 to 10, wherein the binder resin contains a polyester resin.

By the above means of the present invention, it is possible to provide an image forming apparatus capable of suppressing sticking of stacked sheets having an image on which toner is thermally fixed.
The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

In the present invention, it is assumed that the fine particles exhibit the spacer effect by applying the fine particle dispersion to the printed image.
Specifically, by applying the fine particle dispersion, an air layer can be held between papers having printed images (hereinafter also referred to as “printed matter”). For this reason, even if the printed materials are stacked, the printed materials can be prevented from sticking due to electrostatic force.

  In an electrophotographic system, when toner developed on a photoreceptor is transferred onto a sheet, a charge having a polarity opposite to that of the toner (plus charge) is injected into the sheet as a transfer potential. The injected charge is difficult to be removed from the printed matter due to the presence of the toner layer having a high volume resistance, and the fixed printed matter continues to retain the electric charge.

When toner is transferred to the second side of the first side (the side on which the image is placed first) and the second side (the opposite side of the first side) during duplex printing, the transfer current (plus Charge) is injected, and the negative charge originally held by the toner remains held on the second surface, and as a result, a positive charge holding surface and a negative charge holding surface are generated during duplex printing.
When the printed materials are stacked in this state, the printed materials stick to each other by electrostatic force.

  In the case of a material having high electrical resistance such as toner resin or paper, in general, the higher the temperature, the easier the charge leaks. For this reason, the leakage of the charge injected by the transfer depends on the glass transition temperature of the fixing resin and the temperature at the time of fixing. In addition, how to remove the charge depends on the amount of toner attached, and as the amount of adhesion increases, the toner layer becomes thicker and the charge becomes difficult to remove. This phenomenon becomes remarkable in the case of duplex printing.

In the present invention, by applying a fine particle dispersion to a printed image, the fine particles exert a spacer effect, and an air layer can be maintained between the paper (printed matter) (spacer effect).
Since the printed matter has an air layer in this way, it is assumed that the printed matter can be prevented from sticking to each other due to electrostatic force even when the printed matter that cannot leak the electric charge is loaded.
In addition, it is assumed that the present invention can suppress sticking of printed materials to each other by electrostatic force without reducing productivity because of the configuration in which the fine particle dispersion is applied to the printed image.

Sectional drawing which shows an example of the fine particle dispersion | distribution liquid provision unit which concerns on this invention Enlarged view of main part of fine particle dispersion unit Explanatory drawing of the dispersion applying action of the fine particle dispersion applying means Sectional drawing which shows the other example of the fine particle dispersion | distribution liquid provision unit which concerns on this invention 1 is an overall configuration diagram of an image forming system according to the present invention. Schematic explaining the measurement of sticking force

An image forming apparatus according to the present invention includes an image forming unit that forms an image by transferring toner containing at least a binder resin and a release agent onto a sheet, and heats and pressurizes the sheet on which the image is transferred. An image forming apparatus having a fixing device for fixing the image,
And a fine particle dispersion applying unit for applying a fine particle dispersion to the image fixed by the fixing device. This feature is a technical feature common to the inventions according to claims 1 to 11.

In an embodiment of the present invention, the specific gravity of the fine particles contained in the fine particle dispersion is in the range of 0.90 to 2.0 g / cm ³ because the dispersion stability of the fine particle dispersion is improved. Preferably, it is in the range of 0.90 to 1.2 g / cm ³ .
In the present invention, the fine particles contained in the fine particle dispersion contain that the fine particles contained in the fine particle dispersion contain polystyrene resin, acrylic resin, methacrylic resin, urea resin, silicone resin or epoxy resin. It is preferable because the specific gravity is within the above range and the dispersion stability of the fine particle dispersion is improved.

In the present invention, the median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is preferably in the range of 10 to ₅₀ μm, more preferably in the range of 15 to 30 μm. When the median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is within such a range, it becomes larger than the unevenness of the fixed image, and therefore, the spacer effect can be suitably expressed, which is preferable.

  In the present invention, the fine particle dispersion applying unit has a humidifying roller for applying a humidifying liquid to the paper and means for supplying the humidifying liquid to the humidifying roller, and the humidifying liquid is the fine particle dispersion. However, it is preferable because the fine particle dispersion can be uniformly applied to the paper, and as a result, an extremely high effect is exhibited for suppressing image sticking.

  In the present invention, the fine particle dispersion applying unit has a vertical paper conveyance path for guiding the paper downward or upward, a liquid supply unit, a liquid supply roller to which the humidifying liquid is supplied from the liquid supply unit, It is preferable that the humidifying roller is configured to receive the humidifying liquid from the liquid supply roller because the fine particle dispersion liquid can be uniformly applied to the paper, and thus sticking can be further suppressed.

  In the present invention, it is preferable that the fine particle dispersion contains a surfactant because it is possible to suppress sedimentation of the fine particle dispersion over time and, in turn, sticking of stacked paper can be suppressed over a long period of time. .

  In the present invention, the fine particle dispersion applied to one surface of the paper on which the image is fixed is a dispersion dispersed with a cationic surfactant, and is on the opposite side of the one surface. The fine particle dispersion applied to the surface is preferably a dispersion dispersed with an anionic surfactant because sticking can be further suppressed.

  In the present invention, it is preferable that the binder resin contains a polyester resin because the electrical resistance inside the image can be lowered, and as a result, sticking can be further suppressed.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Outline of image forming apparatus>
An image forming apparatus according to the present invention includes an image forming unit that forms an image by transferring toner containing at least a binder resin and a release agent onto a sheet, and heats and pressurizes the sheet on which the image is transferred. A fixing device for fixing the image, comprising a fine particle dispersion applying unit for applying a fine particle dispersion to the image fixed by the fixing device.

In the image forming apparatus of the present invention, as shown in FIGS. 1 and 2 to be described later, the fine particle dispersion applying unit guides the paper downward or upward, a vertical paper conveyance path, a liquid supply unit, and the supply unit. It is preferable that a liquid supply roller to which the humidifying liquid is supplied from a liquid part is provided, and the humidifying roller receives the humidifying liquid from the liquid supplying roller.
In the present invention, “vertical” means within a range of 90 ± 5 ° with respect to the horizontal plane.

[Fine particle dispersion unit]
The fine particle dispersion applying unit according to the present invention applies the fine particle dispersion to the image fixed by the fixing device.

  In the fine particle dispersion applying unit, the aspect of applying the fine particle dispersion is not particularly limited, but has a humidifying roller for applying a humidifying liquid to the paper and a means for supplying the humidifying liquid to the humidifying roller, and the humidifying liquid is The fine particle dispersion allows the humidifying liquid to be uniformly applied to the paper having the image on which the toner has been heat-fixed. As a result, the charge transfer on the image surface is smooth, and as a result, the image sticking is suppressed. It is preferable because an extremely high effect is exhibited.

The amount of the fine particle dispersion liquid applied to the sheet is not particularly limited, in the range of 0.01~0.50g / ^{m 2} to form, more preferably in the range of 0.03~0.10g / ^{m 2} It is preferable because the effect can be suitably exhibited without causing image quality degradation such as stickiness.

(Fine particle dispersion)
The fine particles contained in the fine particle dispersion used in the present invention include silica, calcium carbonate, acrylic resin, styrene resin, phenol resin, urea resin, epoxy resin, silicone resin, fluororesin and other plastics, water Metal oxides such as aluminum oxide and alumina, rubbers such as gum arabic and silicone rubber, ceramics fine particles, and fine particles such as those with starch as the main component and coated with a silicone resin on the surface to give water repellency Instead, known ones can be used.

(specific gravity)
The specific gravity of the fine particles in view of dispersion stability of the fine particle dispersion among them is preferably 2.0 g / cm ³ or less, more preferably 0.9~2.0g / cm ^3, 0.9~1.2g / cm ³ is particularly preferred.
If the specific gravity is 2.0 g / cm ³ or less, the dispersion stability of the fine particle dispersion can be suitably adjusted. As a result, even when the fine particle dispersion is stored for a long period of time, the fine particles do not settle, It is preferable because sticking of stacked sheets can be suppressed over a long period of time. From the viewpoint of such dispersion stability, the specific gravity is preferably low and the lower limit is not particularly limited. However, in consideration of a practical material constituting the fine particles, it is assumed that the specific gravity is actually 0.9 g / cm ³ or more. The
From the viewpoint of realizing the specific gravity in the above range, the fine particles contained in the fine particle dispersion contain polystyrene resin, acrylic resin, methacrylic resin, urea resin, silicone resin or epoxy resin, or from these resins. The resulting fine particles (hereinafter also referred to as “resin fine particles”) are preferable.

(Measurement method of specific gravity)
The specific gravity (true specific gravity) of the fine particles according to the present invention can be measured in accordance with JIS standard (JIS-K-0061 5-2-1) using a Le Chatelier specific gravity bottle.

(Median diameter _(D 50))
The median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is preferably in the range of 10 to ₅₀ μm, and more preferably in the range of 15 to 30 μm.
Within this range, the unevenness of the fixed image becomes larger, and as a result, the spacer effect can be suitably expressed.
In addition, a monodispersed material is preferable because there is no variation in the median diameter (D ₅₀ ) of the fine particles, so that no large fine particles are present, and hence deterioration in image quality can be suppressed.
In the present invention, the median diameter (D ₅₀ ) is a volume-based median diameter and can be measured using, for example, “UPA-150” (manufactured by Microtrack Bell Co., Ltd.).

  In addition, it does not specifically limit as a solvent of the fine particle dispersion used by this invention, What can be used for the below-mentioned humidification liquids, such as ion-exchange water, can be used conveniently.

Moreover, it is good also as a fine particle dispersion by containing the said microparticles | fine-particles in a humidification liquid.
In addition, it is preferable that content of the microparticles | fine-particles in a humidification liquid exists in the range of 1-5 mass% with respect to the whole humidification liquid. Within this range, the effects of the present invention can be appropriately expressed, and the image surface is not sticky.
In addition, if it is 1 mass% or more, the effect of this invention can be expressed suitably. Moreover, if it is 5 mass% or less, since the texture of an image can be made suitable, it is preferable.

<Humidifying liquid>
The humidifying liquid is not particularly limited as long as it does not impair the effects of the present invention. For example, water such as ion-exchanged water, alcohol, or a mixed solvent thereof can be used.
It should be noted that the moistening liquid containing the surfactant can suppress sedimentation of the fine particle dispersion over time, can ensure the stability of the fine particle dispersion, and is therefore loaded. It is preferable because sticking of a sheet can be suppressed over a long period of time.
This is presumably because the hydrophilic group of the surfactant applied to the image surface acts to release charges in the image by adsorbing moisture in the air and making the image surface conductive. .
Further, by adding the surfactant to the humidifying liquid, the wettability of the humidifying liquid with respect to the image is also improved, so that it is considered that this also favors the charge release.

(Surfactant)
The type of the surfactant according to the present invention is not limited. For example, a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and the like can be used.
In addition, it is preferable that content of surfactant in a humidification liquid exists in the range of 0.1-30 mass% with respect to the whole humidification liquid. Within this range, the surface of the image does not become sticky, it is possible to suppress sedimentation of the fine particle dispersion over time, and the stability of the fine particle dispersion can be ensured.

  Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene Alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester , Propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanolamide, poly Polyoxyethylene fatty acid amides, polyoxyethylene alkyl amines, alkyl amine oxides, acetylene glycol, acetylene alcohol, and the like.

  Examples of the anionic surfactant include sodium lauryl sulfate, fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acyl glutamate, acylated peptide , Alkyl sulfonate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulfate , Secondary higher alcohol sulfates, alkyl ether sulfates, secondary higher alcohol ethoxy sulfates, polyoxyethylene alkylphenyl ether sulfates, monoglyculates, fatty acid alkylolamide sulfates, alkyl ether phosphorus Examples include acid ester salts and alkyl phosphate ester salts.

  Examples of amphoteric surfactants include carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like, and nonionic surfactants include polyoxyethylene secondary alcohol ether, polyoxyethylene alkylphenyl ether, Polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene alkyl ether, polyoxyethylene glycerin fatty acid ester, polyoxyethylene castor oil, hydrogenated castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, Fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fat Acid alkanolamide, polyoxyethylene fatty acid amides, polyoxyethylene alkyl amines, alkyl amine oxides, acetylene glycol, acetylene alcohol, and the like.

  Examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like.

In general, since the resin contained in the toner particles for forming an image is easily charged to a negative polarity, it is more effective for the humidifying liquid to contain a cationic surfactant. Since it is obtained, it is preferable.
Furthermore, it is particularly preferable that a quaternary ammonium salt is contained as the cationic surfactant because it is hardly affected by the pH of the humidifying liquid and the amount of metal ions in the humidifying liquid.

  Moreover, you may use a commercial item as a cationic surfactant, for example, the capron B-415, capron B-615, capron B-315, capron B-317S made by Nissin Chemical Laboratory, Inc. Examples include Kapron C-30 and Lion Softer EQ manufactured by Lion Corporation.

  When the fine particle dispersion according to the present invention contains a surfactant, the fine particle dispersion applied to one side of the paper on which the image is fixed is dispersed with a cationic surfactant. It is preferable that the fine particle dispersion applied to the surface opposite to the one surface is a dispersion dispersed with an anionic surfactant. In particular, in double-sided printing, the fine particle dispersion applied to the surface (first surface) into which positive charges are injected is a dispersion in which an anionic surfactant is dispersed, and the surface on which negative charges are held When the fine particle dispersion applied to (second surface) is a dispersion dispersed with a cationic surfactant, the charge of the image can be canceled, and as a result, image sticking can be further suppressed. Therefore, it is preferable.

(alcohol)
As alcohol applicable to this invention, a well-known thing can be used, For example, methanol, ethanol, propyl alcohol, isopropyl alcohol, and butanol can be used.

[Paper]
The paper according to the present invention is not particularly limited as long as it can have an image on which toner is heat-fixed. Specifically, for example, plain paper from high to thin paper, high-quality paper, art paper, Examples thereof include printing paper subjected to a coating process such as coated paper.
The method for thermally fixing the toner is not particularly limited, but a method using a fixing device 8 described later can be suitably used.

[Toner for electrostatic image development]
The toner for developing an electrostatic image according to the present invention (hereinafter also simply referred to as “toner”) includes at least toner particles.
In the present invention, “toner” means an aggregate of “toner particles”.

[Toner particles]
The toner particles according to the present invention comprise toner base particles containing at least a binder resin and a release agent.
In addition, the toner base particles according to the present invention may contain a colorant.
Here, the “toner base particle” of the present invention is a particle containing at least a binder resin and a release agent. The toner base particles can be used as toner particles as they are, but it is usually preferable to use toner particles to which external additives have been added.
Further, the method for producing the toner base particles according to the present invention is not particularly limited, and known methods such as a kneading pulverization method, a suspension polymerization method, an emulsion aggregation method, a dissolution suspension method, a polyester elongation method, and a dispersion polymerization method are used. Is mentioned.

<Binder resin>
When the toner particles according to the present invention are produced by a pulverization method, a dissolution suspension method or the like, examples of the binder resin constituting the toner particles include styrene polymers, acrylic polymers, styrene / acryl resins, and polyester resins. , Silicone polymers, olefin polymers, amide polymers and epoxy polymers.

  Among these, a styrene polymer, an acrylic polymer, a styrene / acrylic resin, and a polyester resin having a low melting property and a high sharp melt property are preferable. These can be used alone or in combination of two or more.

  Further, when the toner particles according to the present invention are produced by a suspension polymerization method, a miniemulsion polymerization aggregation method, an emulsion polymerization aggregation method or the like, as a polymerizable monomer for obtaining each polymer constituting the toner particles, for example, Various known polymerizable monomers such as vinyl monomers can be listed. Moreover, as a polymerizable monomer, it is preferable to use what has an ionic dissociation group in combination. Furthermore, as the polymerizable monomer, a cross-linked binder resin can be obtained using a polyfunctional vinyl monomer.

(Styrene / acrylic resin)
The styrene / acrylic resin is an aromatic vinyl monomer and a (meth) acrylic acid ester monomer has an ethylenically unsaturated bond capable of radical polymerization.

Examples of the aromatic vinyl monomer include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, p-ethyl styrene, p. -N-butyl styrene, p-tert-butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, 2, Examples include 4-dimethylstyrene, 3,4-dichlorostyrene, and derivatives thereof.
These aromatic vinyl monomers can be used alone or in combination of two or more.

Examples of (meth) acrylic acid ester monomers include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, and methacrylic acid. Examples include butyl, hexyl methacrylate, 2-ethylhexyl methacrylate, ethyl β-hydroxyacrylate, propyl γ-aminoacrylate, stearyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like.
These (meth) acrylic acid ester monomers can be used alone or in combination of two or more.

  As the aromatic vinyl monomer and (meth) acrylic acid ester monomer of styrene / acrylic resin, it is preferable to use a large amount of styrene or its derivatives from the viewpoint of obtaining excellent chargeability and image quality characteristics. Specifically, the amount of styrene or its derivative used in all monomers (aromatic vinyl monomers and (meth) acrylic acid ester monomers) used to form styrene / acrylic resins. It is preferable that it is 50 mass% or more.

  In the polymerization of styrene / acrylic resin, it is preferable to perform polymerization in the presence of a radical polymerization initiator, and the timing of addition of the radical polymerization initiator is not particularly limited, but it is easy to control radical polymerization. It is preferable to add after mixing the aromatic vinyl monomer and (meth) acrylic acid ester monomer for forming the polymerization of the styrene / acrylic polymer segment.

  Various known polymerization initiators are preferably used as the polymerization initiator. Specifically, for example, hydrogen peroxide, acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethylbenzoyl peroxide, Lauroyl oxide, ammonium persulfate, sodium persulfate, potassium persulfate, diisopropyl peroxycarbonate, tetralin hydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, pertriphenylacetic acid-tert-butyl hydroperoxide, performic acid- tert-butyl, peracetic acid-tert-butyl, perbenzoic acid-tert-butyl, perphenylacetic acid-tert-butyl, permethoxyacetic acid-tert-butyl, per-N- (3-toluyl) palmitic acid-tert-butyl, etc. Peroxide 2,2'-azobis (2-aminodipropane) hydrochloride, 2,2'-azobis- (2-aminodipropane) nitrate, 1,1'-azobis (1-methylbutyronitrile-3-sulfone) Acid salt), 4,4'-azobis-4-cyanovaleric acid, poly (tetraethylene glycol-2,2'-azobisisobutyrate) and other azo compounds.

  In the polymerization of styrene / acrylic resin, a generally used chain transfer agent can be used for the purpose of adjusting the molecular weight of styrene / acrylic resin. The chain transfer agent is not particularly limited, and examples thereof include alkyl mercaptans and mercapto fatty acid esters.

The chain transfer agent is preferably mixed with the resin material in the mixing step of the aromatic vinyl monomer and the (meth) acrylic acid ester monomer for forming the polymerization of the styrene / acrylic resin.
The addition amount of the chain transfer agent varies depending on the desired molecular weight and molecular weight distribution of the styrene / acrylic resin, but specifically, it is preferably added in the range of 0.1 to 5% by mass with respect to the monomer.
The polymerization temperature in the polymerization of the styrene / acrylic resin is not particularly limited and can be appropriately selected. For example, the polymerization temperature is preferably in the range of 85 to 125 ° C, more preferably in the range of 90 to 120 ° C, and still more preferably in the range of 95 to 115 ° C.
In the present invention, two or more styrene / acrylic resins may be used.

(Polyester resin)
In the present invention, the binder resin preferably contains a polyester resin.
As the polyester resin, any of the following crystalline polyester resin and non-crystalline polyester resin can be used.

(Crystalline polyester resin)
In the present invention, the crystalline polyester resin is a polyester resin having a clear endothermic peak instead of a stepwise endothermic change in differential scanning calorimetry (DSC). Specifically, the endothermic peak means a peak in which the half-value width of the endothermic peak is within 15 ° C., for example, in differential scanning calorimetry (DSC) when measured at a heating rate of 10 ° C./min. To do.

The crystalline polyester resin is preferably contained in the toner base particles in the range of 1 to 30% by mass.
If the content of the crystalline polyester resin in the toner base particles is 1% by mass or more, the effect can be suitably exhibited. Further, when the content of the crystalline polyester resin in the toner base particles is 30% by mass or less, the toner can be prevented from blocking.

  Here, the crystalline polyester resin is obtained by a polycondensation reaction between a divalent or higher carboxylic acid (polyvalent carboxylic acid compound) and a divalent or higher alcohol (polyhydric alcohol compound).

  A polyvalent carboxylic acid compound is a compound having two or more carboxy groups in one molecule, and alkyl esters, acid anhydrides and acid chlorides of polyvalent carboxylic acid compounds can be used. Examples of the polyvalent carboxylic acid compound include oxalic acid, succinic acid, maleic acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, Fumaric acid, citraconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-dicarboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucous acid, phthalic acid, Isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o-phenylenediglycolic acid, Diphenylacetic acid, diphenyl-p, p'-di Divalent carboxylic acids such as rubonic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, anthracene dicarboxylic acid, dodecenyl succinic acid; trimellitic acid, pyromellitic You may combine with trivalent or more carboxylic acids, such as an acid, naphthalene tricarboxylic acid, naphthalene tetracarboxylic acid, pyrene tricarboxylic acid, and pyrene tetracarboxylic acid.

  The polyhydric alcohol compound is a compound having two or more hydroxy groups in one molecule. Examples of the polyhydric alcohol compound include ethylene glycol, propylene glycol, butanediol, diethylene glycol, hexanediol, cyclohexanediol, octanediol, Divalent alcohols such as decanediol, dodecanediol, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A; glycerin, pentaerythritol, hexamethylolmelamine, hexaethylolmelamine, tetramethylolbenzoguanamine, tetraethylolbenzoguanamine And trivalent or higher polyols.

As the catalyst for synthesizing the polyester polymerization segment, various conventionally known catalysts can be used, and for example, an esterification catalyst or the like can be used.
Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin (II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamate. Examples of the esterification cocatalyst include gallic acid and the like. Is mentioned. The amount of the esterification catalyst used is preferably 0.01 to 1.5 parts by mass with respect to 100 parts by mass of the total amount of the polyhydric alcohol compound, polyvalent carboxylic acid compound and both reactive monomer components, -1.0 mass part is more preferable. The amount of the esterification cocatalyst used is preferably 0.001 to 0.5 parts by mass with respect to 100 parts by mass of the total amount of the polyhydric alcohol compound, polyvalent carboxylic acid compound and both reactive monomer components. 01-0.1 mass part is more preferable.

  Examples of combinations of a polyvalent carboxylic acid compound and a polyhydric alcohol compound for forming a crystalline polyester resin that can be used in the present invention include 1,12-dodecanediol (carbon number 12) and sebacic acid (carbon number 10). ), Ethylene glycol (2 carbon atoms) and sebacic acid (10 carbon atoms), 1,6-hexanediol (6 carbon atoms) and dodecanedioic acid (12 carbon atoms), 1,9-nonanediol (6 carbon atoms) And dodecanedioic acid (carbon number 12), 1,6-hexanediol (carbon number 6), sebacic acid (carbon number 10), and the like.

  In addition, it is preferable that melting | fusing point Tm of a crystalline polyester resin particle exists in the range of 65-90 degreeC, More preferably, it exists in the range of 70-80 degreeC. When Tm is in the range of 65 to 90 ° C., the low temperature fixability is not hindered and the heat resistant storage property is improved.

(Measuring method of melting point of crystalline polyester resin)
The melting point of the crystalline polyester resin can be measured by a differential calorimeter (DSC).
For example, it can be performed using a DSC-7 differential scanning calorimeter (manufactured by PerkinElmer) or a TAC7 / DX thermal analyzer controller (manufactured by PerkinElmer). Specifically, 4.50 mg of a sample is sealed in an aluminum pan (KIT No. 0219-0041), which is set in a sample holder of “DSC-7”, and an empty aluminum pan is used for measuring the reference. Heat-Cool-Heat temperature control was performed at a measurement temperature of 0 to 200 ° C. under measurement conditions of a temperature increase rate of 10 ° C./min and a temperature decrease rate of 10 ° C./min. Get data in Heat. The melting point is the temperature at the peak top of the endothermic peak.

(Non-crystalline polyester resin)
In the present invention, the non-crystalline polyester resin is mainly obtained by polycondensation of polyvalent carboxylic acids and polyhydric alcohols, and has a step-like endothermic change in differential scanning calorimetry (DSC). That is, it has no clear endothermic peak. Moreover, in the case of the polymer which copolymerized the other component with respect to the said amorphous polyester principal chain, when another component is 5 mass% or less, this copolymer is also an amorphous polyester resin in this invention.

  Examples of polyvalent carboxylic acids in the non-crystalline polyester resin include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, naphthalenedicarboxylic acid; maleic anhydride, Aliphatic carboxylic acids such as fumaric acid, succinic acid, alkenyl succinic anhydride, and adipic acid; alicyclic carboxylic acids such as cyclohexanedicarboxylic acid, and the use of one or more of these polyvalent carboxylic acids. it can. Among these polyvalent carboxylic acids, aromatic carboxylic acids are preferably used, and trivalent or higher carboxylic acids (trimellitic acid) together with dicarboxylic acids in order to take a crosslinked structure or a branched structure in order to ensure good fixability. And acid anhydrides thereof) are preferably used in combination.

Examples of the polyhydric alcohol in the non-crystalline polyester resin include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentylglycol, glycerin, etc .; cyclohexanediol, cyclohexane Examples include alicyclic diols such as dimethanol; aromatic diols such as an ethylene oxide adduct of bisphenol A and a propylene oxide adduct of bisphenol A. One or more of these polyhydric alcohols can be used. Among these polyhydric alcohols, aromatic diols and alicyclic diols are preferable, and among these, aromatic diols are more preferable. In order to secure better fixability, it is also preferable to use a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol) together with the diol in order to take a crosslinked structure or a branched structure.
In the present invention, two or more amorphous polyesters may be used.

[Colorant]
As the colorant used in the present invention, carbon black, a magnetic material, a dye, a pigment, and the like can be arbitrarily used.

  As the carbon black, channel black, furnace black, acetylene black, thermal black, lamp black and the like are used.

  As the magnetic material, ferromagnetic metals such as iron, nickel and cobalt, alloys containing these metals, and compounds of ferromagnetic metals such as ferrite and magnetite can be used.

  Examples of the dye include C.I. I. Solvent Red 1, 49, 52, 58, 63, 111, 122, C.I. I. Solvent Yellow 19, 44, 77, 79, 81, 82, 93, 98, 103, 104, 112, 162, C.I. I. Solvent Blue 25, 36, 60, 70, 93, 95, etc. can be used, and mixtures thereof can also be used.

  Examples of the pigment include C.I. I. Pigment Red 5, 48: 1, 48: 3, 53: 1, 57: 1, 81: 4, 122, 139, 144, 149, 166, 177, 178, 222, C.I. I. Pigment Orange 31 and 43, C.I. I. Pigment Yellow 14, 17, 74, 93, 94, 138, 155, 180, 185, C.I. I. Pigment green 7, C.I. I. Pigment Blue 15: 3, 15: 4, 60, and the like, and a mixture thereof can also be used.

  The number average primary particle diameter varies depending on the type, but is preferably in the range of about 10 to 200 nm.

[Other additives]
In addition to the components described above, a release agent is added to the toner in this embodiment. Furthermore, various components such as inorganic fine particles (inorganic powder) and organic fine particles can be added as external additives as required.

<Release agent>
Examples of the release agent include polyethylene wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, dialkyl ketone wax such as distearyl ketone, carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetramilliyl. State, pentaerythritol tetrastearate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecanediol distearate, tristearyl trimellitic acid, distearyl male Ester waxes such as ethylene amide, amide waxes such as ethylenediamine dibehenyl amide, trimellitic acid tristearyl amide, etc. It is.

  The content ratio of the release agent in the toner particles is preferably in the range of 2 to 30% by mass, more preferably in the range of 5 to 20% by mass with respect to the total mass of the toner.

<Charge control agent>
In addition, a charge control agent can be added to the toner base particles according to the present invention as necessary. Various known materials can be used as the charge control agent.

  As the charge control agent, various known compounds that can be dispersed in an aqueous medium can be used. Specifically, nigrosine dyes, metal salts of naphthenic acid or higher fatty acids, alkoxylated amines, quaternary Examples include quaternary ammonium salt compounds, azo metal complexes, salicylic acid metal salts or metal complexes thereof.

  The content ratio of the charge control agent is preferably 0.1 to 10% by mass, and more preferably 0.5 to 5% by mass with respect to the total amount of the binder resin.

<External additive>
The inorganic fine particles can be added for various purposes, but known fine inorganic particles such as silica fine particles, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles or those whose surfaces have been hydrophobized are used alone or in combination of two or more. Can be used in combination. Further, the silica fine particles may be subjected to various surface treatments, and for example, those subjected to surface treatment with a silane coupling agent, a titanium coupling agent, silicone oil or the like are preferably used.

≪Toner manufacturing method≫
The toner particles according to the present invention may have, for example, a core / shell structure in which the surface of core particles made of a core resin is covered with a shell layer made of a shell resin, or a single layer structure. May be.

  In the toner of the present invention, an example in which a toner containing a colorant is produced by an emulsion polymerization aggregation method (core-shell structure toner) is specifically shown.

(1-1) Shell resin fine particle dispersion preparing step of forming a shell resin fine particle by a shell resin in an aqueous medium and preparing a dispersion in which the shell resin fine particles are dispersed (1-2) In an aqueous medium The wax-containing core resin fine particle dispersion preparation step for preparing a dispersion liquid in which the wax-containing core resin fine particles containing the wax and the core resin are dispersed. (1-3) The colorant fine particles by the colorant are contained in the aqueous medium. Colorant fine particle dispersion preparation step for preparing a dispersed dispersion (2) Core particle formation step for agglomerating wax-containing core resin fine particles and colorant fine particles in an aqueous medium to form core particles (3) Core particles The core / shell structure is formed by adding the shell resin fine particles to the surface of the core particles and aggregating and fusing the shell resin fine particles into the aqueous medium in which the resin is dispersed. (4) Aging step for adjusting the shape of the toner base particles by thermal energy (5) Separating the toner base particles from a dispersion system (aqueous medium) of the toner base particles And a step of removing the surfactant from the toner base particles. (6) A drying step of drying the toner base particles that have been cleaned.

In addition to the steps (1) to (6) above,
(7) An external additive addition step of adding an external additive to the dried toner base particles can be added.

[(1-1) Shell resin fine particle dispersion preparation step]
In this shell resin fine particle dispersion preparation step, the shell resin fine particle dispersion can be obtained by an aqueous direct dispersion method to which a surfactant is added, for example, by an ultrasonic dispersion method, a bead mill dispersion method, or the like. The average particle diameter of the shell resin fine particles obtained in this shell resin fine particle dispersion preparing step is preferably in the range of, for example, 50 to 500 nm as a volume-based median diameter.

The volume-based median diameter (D ₅₀ ) can be measured using “UPA-150” (manufactured by Microtrack Bell Co., Ltd.).

  In the present invention, the “aqueous medium” refers to a medium comprising 50 to 100% by mass of water and 0 to 50% by mass of a water-soluble organic solvent. Examples of the water-soluble organic solvent include methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran, and alcohol-based organic solvents that do not dissolve the resulting resin are preferable.

<Surfactant>
A dispersion stabilizer is preferably added to the aqueous medium in order to prevent aggregation of dispersed droplets.
As the dispersion stabilizer, surfactants such as various known cationic surfactants, anionic surfactants, nonionic surfactants and the like can be used, and specific examples thereof include those described above. Cationic surfactants and anionic surfactants can be used.

  Specific examples of the nonionic surfactant include dodecyl polyoxyethylene ether, hexadecyl polyoxyethylene ether, norylphenyl polyoxyethylene ether, lauryl polyoxyethylene ether, sorbitan monooleate polyoxyethylene ether, styryl. Phenyl polyoxyethylene ether, monodecanoyl sucrose, etc. are mentioned.

  The above surfactants can be used singly or in combination of two or more as desired.

[(1-2) Wax-containing core resin fine particle dispersion preparation step]
In the wax-containing core resin fine particle dispersion preparing step, resin fine particles containing a wax and a core resin are formed, and this is used for the core particle forming step.

Specifically, the wax-containing core resin fine particles include a wax and, if necessary, a polymerizable monomer for forming the core resin in an aqueous medium containing a surfactant having a critical micelle concentration (CMC) or less. A monomer solution in which other toner components such as a charge control agent are dissolved or dispersed, and mechanical energy is applied at a temperature equal to or higher than the melting point of the wax to form droplets. A polymerization initiator is added to advance the polymerization reaction in the droplets. Note that an oil-soluble polymerization initiator may be contained in the droplet.
In such a wax-containing core resin fine particle dispersion preparation step, mechanical energy is forcibly emulsified (formation of droplets) is essential. Examples of the mechanical energy applying means include strong stirring such as homomixer, ultrasonic wave, and Manton gorin, or ultrasonic vibration energy applying means.

  In some cases, after dissolving the resin and wax in an organic solvent such as ethyl acetate, the solution is added to an aqueous surfactant solution and finely dispersed by mechanical means, and then the solvent can be removed. .

The wax-containing core resin fine particles formed in the wax-containing core resin fine particle dispersion preparing step can also have a structure of two or more layers made of resins having different compositions.
In this case, a polymerization initiator and a polymerizable monomer are added to the dispersion of the first resin particles prepared by emulsion polymerization treatment (first stage polymerization) according to a conventional method, and this system is polymerized (first treatment). Two-stage polymerization) can be employed, and in this case, the wax may be contained in any layer, but in particular in the case of a three-layer structure, the wax is preferably contained in the intermediate layer. .

When a surfactant is used in the wax-containing core resin fine particle dispersion preparation step, the same surfactant as the surfactant that can be used in the above-mentioned shell resin fine particle dispersion preparation step, for example, is used. Can be used.
The core resin fine particles obtained in the wax-containing core resin fine particle dispersion preparation step preferably have a volume-based median diameter (D ₅₀ ) in the range of, for example, 50 to 500 nm.
The volume-based median diameter (D ₅₀ ) can be measured using the above-mentioned “UPA-150” (manufactured by Microtrack Bell).

[(1-3) Colorant fine particle dispersion preparation step]
The colorant fine particle dispersion can be prepared by dispersing a colorant in an aqueous medium. The colorant dispersion treatment is preferably performed in a state where the surfactant concentration in the aqueous medium is not less than the critical micelle concentration (CMC) since the colorant is uniformly dispersed. Various known dispersers can be used as a disperser used for the dispersion treatment of the colorant.
Examples of the surfactant used include the same surfactants as those described above.

The dispersion diameter of the colorant fine particles in the colorant fine particle dispersion prepared in this colorant fine particle dispersion preparing step is preferably 10 to 300 nm in terms of volume-based median diameter (D ₅₀ ).
The volume-based median diameter (D ₅₀ ) of the colorant fine particles in the colorant fine particle dispersion is measured with an electrophoretic light scattering photometer “ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)”.

  When a surfactant is used in this colorant fine particle dispersion preparation step, the same surfactant as the surfactant that can be used in the above-mentioned shell resin fine particle dispersion preparation step, for example, is used. Can be used.

  The colorant may be introduced into the toner particles by, for example, dissolving or dispersing in advance in the monomer solution for forming the core resin in the wax-containing core resin fine particle dispersion preparation step.

[(2) Core particle forming step]
In the core particle forming step, fine particles of other toner constituent components such as a charge control agent can be aggregated together with the fine core resin particles and the fine colorant particles as necessary.

  As a specific method for agglomerating and fusing the core resin fine particles and the colorant fine particles, the flocculant is added to an aqueous medium so as to have a critical aggregation concentration or higher, and then the glass transition point of the core resin fine particles or higher. In addition, by heating the mixture to a temperature equal to or higher than the melting peak temperature (° C.) of the mixture, the salting out of the fine particles such as the core resin fine particles and the colorant fine particles proceeds, and at the same time, the fusion is proceeded in parallel to obtain desired particles In this method, the particle growth is stopped by adding a coagulation terminator when it has grown to the diameter, and further, heating is continued to control the particle shape as necessary.

<Flocculant>
The flocculant that can be used in the core particle forming step is not particularly limited, but a material selected from metal salts can be suitably used.

  Examples of the metal salt include monovalent metal salts such as alkali metal salts such as sodium, potassium and lithium; divalent metal salts such as calcium, magnesium, manganese and copper; and trivalent metal salts such as iron and aluminum. Etc. Specific metal salts can include sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, copper sulfate, magnesium sulfate, manganese sulfate, and the like. It is particularly preferable to use a divalent metal salt. These can be used alone or in combination of two or more.

  When using a surfactant in the core particle forming step, it is possible to use, for example, the same surfactant as the surfactant that can be used in the above-mentioned shell resin fine particle dispersion preparation step. it can.

As for the particle size of the core particles obtained in this core particle forming step, for example, the volume-based median diameter (D ₅₀ ) is preferably in the range of 2 to 9 μm, more preferably in the range of 4 to 7 μm.
The volume-based median diameter (D ₅₀ ) of the core particles is measured by “Coulter Multisizer 3” (manufactured by Beckman Coulter).

[(3) Shelling process]
In this shelling step, the shell resin fine particles are added to the core particle dispersion, the shell resin fine particles are aggregated and fused on the surface of the core particles, and the shell layer is coated on the surface of the core particles to form the toner base particles. Form.

  Specifically, the dispersion of the core particles is added to the dispersion of the shell resin fine particles while maintaining the temperature in the core particle formation step, and the shell resin fine particles are slowly removed over several hours while continuing the heating and stirring. By agglomerating and fusing to the surface of the toner, toner particles are formed by coating the surface of the core particles with a shell layer having a thickness of 100 to 300 nm. The heating and stirring time is preferably 1 to 7 hours, particularly preferably 3 to 5 hours.

[(4) Aging process]
Although the shape of the toner particles in the toner can be made uniform to some extent by controlling the heating temperature in the core particle forming step and the shell forming step, a ripening step is performed in order to further make the shape uniform.
This aging step is controlled by controlling the heating temperature and time so that the surface of the toner base particles formed with a uniform particle size and a narrow distribution has a smooth but uniform shape.

  Specifically, the heating temperature is lowered in the core particle forming step and the shelling step to suppress the progress of fusion between the resin fine particles to promote homogenization, and in this aging step, the heating temperature is lowered, and The toner base particles are controlled to have a desired average circularity by extending the time, that is, to have a uniform surface shape.

[(5) Cleaning step and (6) Drying step]
The washing step and the drying step are steps for washing and drying the toner base particles.
The specific method of washing and drying is not particularly limited, and various known methods can be adopted as long as they do not inhibit the effects of the present invention.

(7) External additive addition step This external additive addition step is a step of adding and mixing external additives as necessary to the dried toner base particles.
The toner base particles produced through the steps up to the drying step can be used as toner particles as they are, but from the viewpoint of improving the charging performance, fluidity or cleaning properties of the toner, the surface thereof is known. It is preferable to add particles such as inorganic fine particles and organic fine particles, and a lubricant as external additives.

  Various external additives may be used in combination. The amount of these external additives added is 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the toner base particles.

  Examples of the method of adding the external additive include a dry method in which the external additive is added in powder form to the dried toner base particles. Examples of the mixing device include mechanical mixing devices such as a Henschel mixer and a coffee mill. It is done.

[Average particle diameter of toner particles]
The average particle diameter of the toner particles according to the present invention is preferably 3 to 9 μm, and more preferably 3 to 8 μm, for example, in terms of volume-based median diameter (D ₅₀ ). This particle size can be controlled by the concentration of the coagulant used, the addition amount of the organic solvent, the fusing time, the composition of the polymer, and the like, for example, when the emulsion aggregation method described later is employed.

When the volume-based median diameter (D ₅₀ ) is in the above range, the transfer efficiency is increased, the image quality of halftone is improved, and the image quality of fine lines and dots is improved.
The volume-based median diameter (D ₅₀ ) of the toner particles is measured using a measuring device in which a computer system equipped with data processing software “Software V3.51” is connected to “Multisizer 3” (manufactured by Beckman Coulter). Measured and calculated.

Specifically, 0.02 g of toner is added to 20 mL of a surfactant solution (for example, a surfactant solution obtained by diluting a neutral detergent containing a surfactant component 10 times with pure water for the purpose of dispersing toner particles). Then, ultrasonic dispersion is performed for 1 minute to prepare a toner dispersion, and this toner dispersion is placed in a beaker containing “ISOTON II” (manufactured by Beckman Coulter) in a sample stand. Pipet until the indicated concentration is 8%. Here, a reproducible measurement value can be obtained by setting the concentration range. In the measurement apparatus, the measurement particle count is 25000, the aperture diameter is 50 μm, the frequency value is calculated by dividing the measurement range of 1 to 30 μm into 256, and the volume integrated fraction is 50 % Particle diameter is defined as the volume-based median diameter (D ₅₀ ).

[Average circularity of toner particles]
The toner according to the present invention preferably has an average circularity of 0.930 to 1.000, and more preferably 0.940 to 1.000 from the viewpoint of improving transfer efficiency for each toner particle constituting the toner. 0.995.
In the present invention, the average circularity of toner particles is measured using “FPIA-2100” (manufactured by Sysmex).

Specifically, the sample (toner particles) is blended with an aqueous solution containing a surfactant, subjected to ultrasonic dispersion treatment for 1 minute to disperse, and then subjected to measurement conditions HPF by “FPIA-2100” (manufactured by Sysmex). In the (high magnification imaging) mode, photographing is performed at an appropriate density with an HPF detection number of 3000 to 10,000, the circularity is calculated for each toner particle according to the following formula (T), and the circularity of each toner particle is added. , By dividing by the total number of toner particles.
Formula (T): Circularity = (perimeter of a circle having the same projection area as the particle image) / (perimeter of the particle projection image)

[Developer]
The toner according to the present invention can be suitably used as a developer, and can be used as a one-component developer or a two-component developer.
When used as a two-component developer, it is preferably mixed with a carrier.

  There is no restriction | limiting in particular as a carrier which can be used for a two-component developer, A well-known carrier can be used. For example, magnetic metals such as iron oxide, nickel and cobalt, magnetic oxides such as ferrite and magnetite, etc., and using these as a core material, a resin-coated carrier having a resin coating layer on the core material surface, a magnetic dispersion type carrier, etc. Can be mentioned. Further, a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin may be used.

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

  Examples of the core material of the carrier include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, it is a magnetic material. It is preferable. The volume average particle diameter of the carrier core material is generally in the range of 10 to 200 μm, and preferably in the range of 25 to 100 μm.

  Moreover, in order to coat | cover resin on the surface of the core material of a carrier, the method etc. which coat | cover with the solution for coating layer formation which melt | dissolved coating resin and various additives in the suitable solvent as needed are mentioned. The solvent is not particularly limited, and may be appropriately selected in consideration of the coating resin to be used, application suitability, and the like.

  The mixing ratio (mass ratio) of the toner according to the present invention and the carrier in the two-component developer is not particularly limited, but from the viewpoint of chargeability and storage stability, toner: carrier = 1: 100 to 30: 100. The range is preferable, and the range of 3: 100 to 20: 100 is more preferable.

<< Specific Example of Image Forming Apparatus of the Present Invention >>
Hereinafter, specific examples of the fine particle dispersion applying unit in the image forming apparatus of the present invention will be described with reference to the examples illustrated in FIGS. 1 to 5, but the present invention is not limited to the examples illustrated in FIGS. 1 to 5.
In the following example, the image forming apparatus includes an image forming unit and a fine particle dispersion applying unit.

  FIG. 1 is a cross-sectional view showing an example of a fine particle dispersion applying unit according to the present invention. In the example of the fine particle dispersion applying unit described with reference to FIGS. 1 to 5, the humidification mode, the no-treatment mode as described in paragraphs 0020 to 0063 of JP-A-2007-286151, the first curl It is preferable that the correction mode and the second curl correction mode are selectable.

  A sheet on which an image is formed in an image forming unit A (described later) (that is, a sheet having an image on which toner is thermally fixed. Hereinafter, it is also simply referred to as “sheet S”). It is introduced into the transport path HR1 of the applying unit B, selectively passes through the transport paths HR2 and HR3, processed, and discharged from the fine particle dispersion applying unit B.

  A fine particle dispersion applying unit 110 is disposed in the transport path HR3. The fine particle dispersion applying unit 110 is formed so as to be able to be pulled out from the fine particle dispersion applying unit B by guiding the rails 120A and 120B.

  In the transport path HR1, the paper S is transported by the roller R1, and in the transport path HR2, the paper S is transported by the rollers R2 to R5. In the transport path HR3, the paper S is transported by the rollers R6 to R11.

  Below the fine particle dispersion applying means 110, a tank 130 for storing a humidifying liquid which is a fine particle dispersion according to the present invention is arranged. The tank 130 can be pulled out from the fine particle dispersion applying unit B by the guides of the rails 131 and 132. Formed.

  FIG. 2 is an enlarged view of a main part of the fine particle dispersion applying unit B. FIG. The fine particle dispersion applying unit B includes a fine particle dispersion applying unit 110 and a tank 130 (shown in FIG. 1).

  The sheet conveyance path HR3 is a vertical sheet conveyance path that guides the sheet downward or upward, and is formed in a U-shape. The sheet S travels vertically downward from the sheet conveyance path HR1 (shown in FIG. 1). The fine particle dispersion applying unit 110 is arranged symmetrically in the left and right portions of the sheet conveyance path HR3 that travels upward in the U-turn and proceeds vertically. Humidification rollers 111A and 111B are arranged so as to contact each other.

The fine particle dispersion applying unit 110 includes a pair of fine particle dispersion applying units, that is, a left fine particle dispersion applying unit 110A and a right fine particle dispersion applying unit 110B.
In addition, it is preferable that the fine particle dispersion applying unit according to the present invention includes a humidifying roller that applies a humidifying liquid that is a fine particle dispersion to a sheet and a unit that supplies the humidifying liquid to the humidifying roller as described later.

The fine particle dispersion applying unit 110A includes a humidifying roller 111A, a liquid supply roller 112A as a means 118A for supplying a humidifying liquid as a fine particle dispersion to the humidifying roller 111A, and a liquid supply tank 114A as a liquid supply unit. The fine particle dispersion applying unit 110B includes a humidification roller 111B, a liquid supply roller 112B as a unit 118B for supplying the humidification liquid to the humidification roller 111A, and a liquid supply tank 114B as a liquid supply unit.
When the humidifying rollers 111A and 111B come into contact with each other and rotate as indicated by arrows to convey the paper S, the humidifying liquid is applied to the paper S to perform humidification. In addition, a relay roller (not shown) is interposed between the liquid supply rollers 112A and 112B and the liquid supply tanks 114A and 114B, and the liquid supply part that supplies the humidifying liquid to the liquid supply rollers 112A and 112B is provided as the liquid supply tank. And a relay roller.

As described above, in the illustrated example, the means 118A and 118B for supplying the humidifying liquid have the liquid supply rollers 112A and 112B and the liquid supply tanks 114A and 114B.
The liquid supply roller 112A is in contact with the humidification roller 111A, the liquid supply roller 112B is in contact with the humidification roller 111B, and the liquid supply roller 112A is in contact with the humidification liquid W stored in the liquid supply tank 114A. Are respectively immersed in the humidifying liquid W accommodated in the liquid supply tank 114B. In this way, the humidifying liquid W is supplied to the liquid supply rollers 112A and 112B from the liquid supply tanks 114A and 114B which are liquid supply units.

  113A and 113B are control members that press the liquid supply rollers 112A and 112B to regulate the amount of the humidifying liquid.

As the humidifying rollers 111A and 111B and the liquid supply rollers 112A and 112B, a single-layer or multi-layer roller made of an elastic material such as solid rubber or foam rubber or a multi-layer roller in which fibers are wound around rubber is used. It is done.
The humidifying roller 111A is preferably composed of an axial core 111Aa made of metal and a rubber layer 111Ab formed thereon.
The humidifying roller 111B is preferably composed of a shaft 111Ba made of metal and a rubber layer 111Bb formed thereon.
The liquid supply roller 112A is preferably composed of a shaft 112Aa made of metal and a rubber layer 112Ab formed thereon.
The liquid supply roller 112B is preferably composed of a shaft 112Ba made of metal and a rubber layer 112Bb formed thereon.

  A rotating or fixed round bar is used for the control members 113A and 113B. Further, plate-like blades can be used as the control members 113A and 113B.

  The humidifying liquid W in the tank 130 is pumped up to the liquid supply tanks 114A and 114B by a pump (not shown), and is returned to the tank 130 from the overflow pipe 116 due to the overflow, so that the humidifying liquid W in the liquid supply tanks 114A and 114B The water level is kept constant. The liquid supply tanks 114A and 114B communicate with each other, and the water levels in both are maintained at the same level.

  In the humidification process, the humidification rollers 111A and 111B and the liquid supply rollers 112A and 112B rotate as indicated by arrows, respectively, and apply the humidification liquid to both surfaces of the paper S, whereby the fine particle dispersion is applied to the image fixed by the fixing device. Is granted.

  As shown in FIGS. 1 and 2, the humidifying rollers 111A and 111B and the liquid supply rollers 112A and 112B are arranged symmetrically about the paper transport path HR3, so that the supply from the liquid supply tank 114A to the humidification roller 111A is performed. The liquid path and the liquid supply path from the liquid supply tank 114B to the humidification roller 111B are the same in terms of shape and length.

  Therefore, uniform humidification is performed from both sides of the paper S. Further, since the sheet S is humidified in the sheet conveyance path HR3 that rises vertically, a uniform amount of humidification liquid is supplied in the thickness direction of the sheet S, and the flatness of the sheet S is maintained well. Can do.

  With reference to FIG. 3, the dispersion applying action of the fine particle dispersion applying means will be described.

In the fine particle dispersion applying unit 110A, the liquid supply path WH1 passes through the surface of the liquid supply roller 112A and the surface of the humidification roller 111A from the position P1 at which the liquid supply roller 112A comes into contact with the liquid surface of the humidifying liquid W that is the fine particle dispersion. This is a liquid supply path of the humidifying liquid W that reaches the humidifying position P2 where the humidifying roller 111A contacts the paper S.
In the fine particle dispersion applying unit 110B, the liquid supply path WH2 passes through the surface of the liquid supply roller 112B and the surface of the humidification roller 111B from the position P3 where the liquid supply roller 112B comes into contact with the liquid surface of the humidifying liquid W that is the fine particle dispersion. This is a liquid supply path of the humidifying liquid W that reaches the humidifying position P2 where the humidifying roller 111B contacts the paper S.
Through such liquid supply paths WH1 and WH2, the humidifying rollers 111A and 111B can receive the humidified liquid from the liquid supply rollers 112A and 112B.

  In the fine particle dispersion applying unit 110, the length and shape of the liquid supply path WH1 and the liquid supply path WH2 are the same. Therefore, the amount of the humidifying liquid applied to both sides of the paper S by the humidifying rollers 111A and 111B is equal, and even if the state of the humidifying rollers 111A and 111B and the liquid supply rollers 112A and 112B changes slightly due to aging, The ratio of the liquid volume hardly changes.

  Therefore, in the fine particle dispersion applying unit of the illustrated example, an equal amount of fine particle dispersion is applied to both sides of the paper S over a long period of time, thereby providing a stable long-term fine particle dispersion.

  117A and 117B are fans that blow dry air on both sides of the paper S. By blowing dry air on the paper S with the fans 117A and 117B, excess humidified liquid is evaporated from the paper S immediately after humidification, and a transport roller or the like is used. It prevents the humidifying liquid from accumulating on the sheet conveying path forming member.

  In the fine particle dispersion applying unit in the illustrated example, the fine particle dispersion applying units 110A and 110B are provided on both sides of the paper conveyance path for conveying the paper S in the vertical direction, but the paper for conveying the paper in the vertical direction below. Particulate dispersion applying means may be provided on both sides of the transport path. Further, the pair of fine particle dispersion applying means is not completely symmetrical, and may be slightly deviated from the symmetrical arrangement as long as it is substantially symmetrical. For example, the height of the right and left fine particle dispersion applying means May be different.

  The fine particle dispersion applying unit shown in FIG. 1 may have curl correcting means 150 and 160 as described in paragraphs 0020 to 0063 of JP-A-2007-286151.

Incidentally, as a tank 130, as shown in FIG. 4, provided two first tank 130A and the second tank 130B, for example, in the first tank, the dispersion W _A dispersed in cationic surfactant and it may be an anionic surfactant dispersion W _B dispersed in to accommodate each of the second tank.
In this case, for example, the fine particle dispersion liquid deposition unit 110A dispersion W _A dispersed in a cationic surfactant from the first tank 130A is supplied from the means 118A for supplying a humidifying solution described above, applying the fine particle dispersion the unit 110B preferably anionic surfactant dispersion W _B dispersed in from the second tank 130B is supplied from the means 118B for supplying the moisturizing liquid above.
In this way, the dispersion liquid dispersed with the cationic surfactant is applied to one side of the paper on which the image is fixed, and the dispersion liquid dispersed with the anionic surfactant is applied to the one side. It can apply | coat to the surface on the opposite side.
As a result, during double-sided printing, a dispersion liquid dispersed with an anionic surfactant is applied to the first surface where positive charges are injected, and the second surface where negative charges are retained is dispersed with a cationic surfactant. The dispersion liquid can be applied and the charge of the image can be canceled out. As a result, image sticking can be further suppressed, which is preferable.

≪Image forming device≫
FIG. 5 is an overall configuration diagram of an image forming apparatus 1 according to the present invention including an image forming unit A, a fine particle dispersion applying unit B, and a bookbinding unit C as a paper post-processing apparatus.

  As a means for forming an image on a sheet, the image forming unit A includes a charging means 2, an image exposure means (writing means) 3, a developing means 4, a transfer means 5A, a charge eliminating means 5B, It has an image forming part in which the cleaning means 6 is arranged.

The image forming unit transfers the toner onto a sheet to form an image.
Specifically, the image forming unit performs exposure scanning based on image data read from the original by the laser beam of the image exposure unit 3 after the charging unit 2 uniformly charges the surface of the image carrier 9. To form a latent image, and the latent image is reversely developed by the developing means 4 to form a toner image on the surface of the image carrier 9.

  The paper S fed from the paper storage unit 7A is sent to the transfer position. The toner image is transferred onto the paper S by the transfer means 5A at the transfer position. Thereafter, the charge on the back surface of the sheet S is erased by the charge removing unit 5B, separated from the image carrier 9, and conveyed by the conveying unit 7B, and subsequently heated and fixed by the fixing device 8, and discharged from the sheet discharge roller 7C. It is fed into the dispersion applying unit B.

The fixing device 8 heats and pressurizes the sheet on which the image is transferred to fix the image.
In the illustrated example, there are a heating roller 8A, a pressure roller 8B in pressure contact with the heating roller 8A, and a heater 8C. The unfixed toner image is heated by the heating roller 8A heated by the heater 8C, and the toner is melted to form a toner image. Is fixed on the paper S.
In this way, a sheet S having an image on which toner is heat-fixed is obtained.

  When image formation is performed on both sides of the sheet S, the sheet S heated and fixed by the fixing device 8 is branched from the normal sheet discharge path by the sheet conveyance path switching plate 7D and switched back in the reverse conveyance section 7E. After reversing the front and back, it passes through the image forming section again, forms an image on the back surface of the paper S, and is discharged from the discharge roller 7C to the outside of the apparatus via the fixing device 8. The paper S discharged from the paper discharge roller 7C is sent to the gluing bookbinding unit C via the fine particle dispersion applying unit B described above.

  The developer remaining on the surface of the image carrier 9 after image processing is removed by the cleaning means 6 to prepare for the next image formation.

  The bookbinding unit C includes a sheet transport unit 210, a sheet discharge unit 220, a cover sheet supply unit 230, a sheet bundle storage unit 240, a sheet bundle transport unit 250, a glue application unit 260, a cover sheet pasting unit 270, a cover sheet folding unit 280, and a booklet discharge unit. 290. Each of the means is arranged in a vertical line in the gluing bookbinding apparatus main body.

  When the sheet conveyance is set, the sheet conveyance path to the sheet bundle housing unit 240 is blocked and the sheet conveyance path to the sheet discharge unit 220 is opened.

  When the bookbinding mode is set, the sheets S are stored in a predetermined position of the sheet bundle storing unit 240 and sequentially stacked, and a sheet bundle including a predetermined number of sheets S is formed. The sheet bundle on the sheet bundle accommodating means 240 is sent to the sheet bundle holding means 250, and the glue is applied to the bottom surface of the sheet bundle by the glue applying means 260 in a state where the sheet bundle holding means 250 rotates and becomes vertical. A bundle of paper is bundled.

  A front cover is supplied from the front cover pasting unit 270 to the bundle of bundles, the front cover is joined, and the front cover folding unit 280 folds the front cover to form a booklet.

  The formed booklet is discharged from the bookbinding unit C by the booklet discharge means 290.

  The bookbinding unit C is described in Japanese Patent Application Laid-Open No. 2003-209869.

  The fine particle dispersion applying unit B may be integrated with the image forming unit A, or may be the image forming unit A provided with the fine particle dispersion applying unit B.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

For example, in the toner manufacturing method described above, the wax is not a method of introducing the styrene / acrylic resin constituting the core resin into the core particles by the miniemulsion method, which is included when the styrene / acrylic resin constituting the core resin is polymerized. May be.
For example, in the same manner as the colorant fine particles, a dispersion of wax fine particles consisting of only wax is separately prepared, and this is aggregated together with the core resin fine particles not containing wax and the colorant fine particles in the core particle forming step to form the core particles. Therefore, it is possible to adopt a method of introducing into the core particles.
However, in the method for producing the toner of the present invention, it is preferable to employ a method in which the wax is introduced into the core particles by the miniemulsion method.

  The embodiments to which the present invention can be applied are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "mass part" or "mass%" is represented.
In Table 1, the resin fine particle dispersions 1 to 15 used in the following Examples 1 to 16 and Comparative Examples 1 to 3 are represented by fine particle resin species (described as “fine particle species” in Table 1). The specific gravity of the fine particles, the surfactant type, and the median diameter (D ₅₀ ) of the fine particles are collectively described.
Details are as follows.

[Example 1]
<Styrene-acrylic / non-crystalline polyester toner, core: styrene-acrylic resin / shell: non-crystalline polyester core-shell toner>
(1-1) Preparation of Amorphous Polyester Resin Dispersion (1) for Shell Synthesis of Amorphous Polyester Resin [A-PEs] In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introducing tube, bisphenol A 316 parts by mass of propylene oxide 2-mole adduct, 80 parts by mass of terephthalic acid, 34 parts by mass of fumaric acid and 2 parts by mass of titanium tetraisopropoxide as a polycondensation catalyst were added in 10 portions and placed at 200 ° C under a nitrogen stream. The reaction was carried out for 10 hours while distilling off the water produced. Subsequently, it was made to react under reduced pressure of 13.3 kPa (100 mmHg), and it took out when the softening point became 104 degreeC, and obtained amorphous polyester resin [A-PEs].

As a shell resin, 100 parts by mass of an amorphous polyester resin [A-PEs] was dissolved in 400 parts by mass of ethyl acetate.
Subsequently, 25 mass parts of 5.0 mass% sodium hydroxide aqueous solution was added, and the resin solution was formed. This resin solution was put into a container having a stirrer, and 400 parts by mass of a 0.26 mass% sodium lauryl sulfate aqueous solution was dropped and mixed over 30 minutes while stirring the resin solution. During the dropping of the sodium lauryl sulfate aqueous solution, the liquid in the reaction vessel became cloudy, and after the entire amount of the sodium lauryl sulfate aqueous solution was dropped, an emulsion was formed in which the resin solution particles were uniformly dispersed.

  Next, the emulsion was heated to 40 ° C., and using a diaphragm vacuum pump “V-700” (manufactured by BUCHI), ethyl acetate was distilled off under a reduced pressure of 150 hPa to obtain a solid content of 20%. “Amorphous polyester resin dispersion for shell (1)” was obtained.

(1-2) Preparation of Wax-Containing Styrene-Acrylic Resin Particle Dispersion (1) for Core (1-2-1) First Stage Polymerization Agitator, temperature sensor, temperature controller, cooling pipe and nitrogen introduction device are attached. An anionic surfactant solution prepared by dissolving 2.0 parts by mass of the anionic surfactant “sodium lauryl sulfate” in 2900 parts by mass of ion-exchanged water in advance was added to the reaction vessel and stirred at a stirring speed of 230 rpm under a nitrogen stream. The internal temperature was raised to 80 ° C.
To this surfactant solution, 9.0 parts by mass of a polymerization initiator “potassium persulfate: KPS” was added and the internal temperature was adjusted to 78 ° C.

Styrene 540 parts by weight n-butyl acrylate 270 parts by weight Methacrylic acid 65 parts by weight n-octyl mercaptan 17 parts by weight

A solution (1) consisting of 3 parts was added dropwise over 3 hours, and after completion of the dropwise addition, polymerization (first stage polymerization) was carried out by heating and stirring at 78 ° C. for 1 hour to obtain a “dispersion of resin particles [a1]”. Prepared.

(1-2-2) Second-stage polymerization: formation of intermediate layer In a flask equipped with a stirrer, the following styrene 94 parts by mass n-butyl acrylate 60 parts by mass methacrylic acid 11 parts by mass n-octyl mercaptan 5 parts by mass

To the solution (2) comprising 51 parts by weight of paraffin wax (melting point: 73 ° C.) as a release agent was added, and the mixture was heated to 85 ° C. and dissolved to prepare a monomer solution [2].

  On the other hand, a surfactant solution in which 2 parts by mass of the anionic surfactant “sodium lauryl sulfate” was dissolved in 1100 parts by mass of ion-exchanged water was heated to 90 ° C. After adding 28 parts by mass of “dispersion of resin particles [a1]” in terms of solid content of resin particles [a1] to this surfactant solution, mechanical disperser “Clairemix” (M The above-mentioned monomer solution [2] was mixed and dispersed for 4 hours by Technic Co., Ltd. to prepare a dispersion containing emulsified particles having a dispersed particle diameter of 350 nm. To this dispersion was added an initiator aqueous solution in which 2.5 parts by mass of a polymerization initiator “KPS” was dissolved in 110 parts by mass of ion-exchanged water, and this system was polymerized by heating and stirring at 90 ° C. for 2 hours. (Second-stage polymerization) was performed to prepare “dispersion of resin particles [a11]”.

(1-2-3) Third-stage polymerization: formation of outer layer In the above-mentioned “dispersion of resin particles [a11]”, 2.5 parts by mass of a polymerization initiator “KPS” was dissolved in 110 parts by mass of ion-exchanged water. Under the temperature condition of 80 ° C.

Styrene 230 parts by mass n-butyl acrylate 100 parts by mass n-octyl mercaptan 5.2 parts by mass

The solution (3) consisting of was added dropwise over 1 hour. After completion of the dropwise addition, polymerization (third stage polymerization) was carried out by heating and stirring for 3 hours. Then, it cooled to 28 degreeC and prepared "the wax-containing styrene-acryl resin particle dispersion liquid (1) for cores" which dispersed the resin particles for cores (1) in the anionic surfactant solution.

(1-3) Preparation of Colorant Dispersion Solution 90 parts by mass of sodium dodecyl sulfate was stirred and dissolved in 1600 parts by mass of ion-exchanged water. While stirring this solution, 420 parts by mass of carbon black “Mogal L” (manufactured by Cabot) was gradually added.

  Subsequently, a “colorant particle dispersion” in which the colorant particles were dispersed was prepared by performing a dispersion treatment using a stirrer “CLEARMIX” (manufactured by M Technique Co., Ltd.). When the particle size of this dispersion was measured using a nanotrack particle size distribution analyzer UPA-EX150 (manufactured by Nikkiso Co., Ltd.), the average particle size was 117 nm.

(1-4) Preparation of dispersion of toner base particles (aggregation / fusion process)
In a reaction vessel equipped with a stirrer, a temperature sensor, and a cooling tube, 288 parts by mass of styrene-acrylic resin particle dispersion (1) for wax-containing core (1 part) in terms of solid content and 2,000 parts by mass of ion-exchanged water were added. A 5 mol / L aqueous sodium hydroxide solution was added to adjust the pH to 10 at 25 ° C. Thereafter, 40 parts by mass of the “colorant particle dispersion” was added in terms of solid content.

Next, an aqueous solution in which 60 parts by mass of magnesium chloride was dissolved in 60 parts by mass of ion-exchanged water was added over 10 minutes at 30 ° C. with stirring.
Thereafter, the temperature was raised after being allowed to stand for 3 minutes, and the temperature of the system was raised to 80 ° C. over 60 minutes, and the particle growth reaction was continued while maintaining 80 ° C. In this state, the particle size of the associated particles was measured with “Coulter Multisizer 3” (manufactured by Beckman Coulter), and when the median diameter (D ₅₀ ) on the volume basis reached 6.0 μm, When 72 parts by mass of the crystalline polyester resin dispersion liquid (1) ”is added over 30 minutes and the supernatant of the reaction solution becomes transparent, 190 parts by mass of sodium chloride is added to 760 parts by mass of ion-exchanged water. The aqueous solution dissolved in was added to stop particle growth.

  Further, the temperature is raised and the mixture is heated and stirred in a state of 90 ° C. to advance the fusing of the particles, and the average circularity measurement apparatus “FPIA-2100” (manufactured by Sysmex) is used (HPF detection). When the average circularity reached 0.945, the mixture was cooled to 30 ° C. to prepare “Styrene-acrylic / non-crystalline polyester toner base particle dispersion”.

(1-5) Washing step and (1-6) Drying step The particles produced in the step (3) (“Styrene-acrylic / non-crystalline polyester toner base particle dispersion”) are solidified with a centrifuge. Liquid separation was performed to form a wet cake of toner base particles. The wet cake was washed with ion-exchanged water at 35 ° C. until the electric conductivity of the filtrate reached 5 μS / cm in the centrifuge. Thereafter, it was transferred to a “flash jet dryer” (manufactured by Seishin Enterprise Co., Ltd.) and dried until the water content became 0.5 mass% to produce “styrene-acrylic / amorphous polyester toner base particles”.

(1-7) External additive treatment step In the above "styrene-acrylic / non-crystalline polyester toner base particles", the number average primary particle having a number average primary particle size of 12 nm as hydrophobic silica is 1% by mass. Using a mixed system in which the particle size is 80 nm and 0.3% by mass, hydrophobic silica and hydrophobic titania (number average primary particle size = 20 nm) 0.3% by mass are added to this mixed system, and Henschel is added. “Toner 1” was prepared by mixing with a mixer.

(1-8) Production of developer 100 parts by mass of ferrite core and 5 parts by mass of copolymer resin particles of cyclohexyl methacrylate / methyl methacrylate (copolymerization ratio 5/5) were charged into a high-speed mixer equipped with stirring blades. The mixture was stirred and mixed at 120 ° C. for 30 minutes to form a resin coat layer on the surface of the ferrite core by the action of mechanical impact force, and a carrier having a volume-based median diameter (D ₅₀ ) of 40 μm was obtained.
The volume-based median diameter (D ₅₀ ) of the carrier was measured by a laser diffraction particle size distribution measuring apparatus “HELOS” (manufactured by Sympathic) equipped with a wet disperser.
To the carrier, the produced toner 1 is added so that the toner concentration is 6% by mass, and the toner is introduced into a micro-type V-type mixer (Tsutsui Riken Kikai Co., Ltd.), mixed at a rotational speed of 45 rpm for 30 minutes, and developed. Was made.

(1-9) Manufacture of resin fine particle dispersion (1-9-1) Manufacture of resin fine particle 1 After mixing 1000 g of polymethacrylic acid (PMMA) resin with a Henschel mixer, two rolls whose roll surface was set to 100 ° C. Kneading for 30 minutes, rolling and cooling, coarse pulverization, jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industrial Co., Ltd.) and wind classifying by swirling flow (DS classifier: Nippon Pneumatic Industrial Co., Ltd.) Resin fine particles 1 were obtained.

(1-9-2) Preparation of Resin Fine Particle Dispersion 1 In a reaction vessel equipped with a stirrer, 2.0 parts by mass of the cationic surfactant “Capron B-415” was dissolved in 1000 parts by mass of ion-exchanged water in advance. The cationic surfactant solution was charged, 20 parts by mass of resin fine particles 1 were added, and the mixture was stirred at 300 rpm for 10 minutes to prepare resin fine particle dispersion 1.
The median diameter (D ₅₀ ) was measured by UPA and found to be D ₅₀ = 20.1 μm.

(Measurement method of specific gravity)
About the specific gravity (true specific gravity) of the microparticles | fine-particles which concern on this invention, it measured as follows based on JIS specification (JIS-K-0061 5-2-1) using the Le Chatelier specific gravity bottle.
(1) About 250 mL of ethyl alcohol is put into a Lechatelier specific gravity bottle and adjusted so that the meniscus is at the position of the scale. Next, the Lechatelier specific gravity bottle is immersed in a constant temperature water tank, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the Lechatelier specific gravity bottle (accuracy is 0.025 mL). ).
(2) About 100 g of fine particles as a sample (mass W) are placed in a Le Chatelier specific gravity bottle, and bubbles are removed.
The Lechatelier specific gravity bottle is immersed in a constant temperature water bath, and when the liquid temperature reaches 20.0 ± 0.2 ° C., the position of the meniscus is accurately read on the scale of the specific gravity bottle (accuracy is 0.025 mL).
(3) The true specific gravity can be calculated by the following equation.
D = W / (L2-L1)
S = D / 0.9982
In the above formula, D represents the density (g / cm ³ ) of fine particles used as a sample at 20 ° C. S represents the true specific gravity of the fine particles used as a sample at 20 ° C. W represents the apparent mass (g) of the fine particles used as a sample. L1 represents the reading (mL) of the meniscus before putting the microparticles (20 ° C.) as a sample into the specific gravity bottle. L2 represents the meniscus reading (mL) after the fine particles (20 ° C.) as a sample are placed in a specific gravity bottle. 0.9982 is the density of water at 20 ° C. (g / cm ³ ).

<Evaluation>
(Humidifying device and image forming device)
2 L of the resin fine particle dispersion 1 is placed in the tank provided in the humidifying apparatus shown in FIG. 2 and it is confirmed that the humidifying roller is wet. Then, the humidifying apparatus is mounted on “bizhub PRESS C1070 (manufactured by Konica Minolta)”. A solid image (toner adhesion amount: 11.3 g / m ² ) is printed on both sides in an environment (hereinafter also referred to as “NN environment”) at a temperature of 20 ° C. and a humidity of 50 RH% (“print pattern” in Table 2). And printed 100 sheets (paper type: OK top coat paper (manufactured by Oji Paper Co., Ltd.) A3 157 g / m ² ).
Twenty-four hours later, sticking force measurement was performed as described below, and further, the texture of the image was evaluated and the results are shown in Table 2.
In Example 1, a resin fine particle dispersion applied on the first surface (“first surface side coating liquid” described in Table 2) and a resin fine particle dispersion applied on the second surface (“2 described in Table 2” The same surface coating solution ")) was used.

(Adhesion force measurement)
Using “bizhub PRESS C1070 (manufactured by Konica Minolta)”, 100 sheets of solid images (toner adhesion amount: 10.5 g / m ² ) were output on both sides (paper type: OK top coat paper (manufactured by Oji Paper Co., Ltd.)) A3 157 g / m ² ). Among the stacked output images, eleven out of the 70 to 80 sheets from the top were extracted and placed on a flat table, and a tape was attached to the tip of the shortest side of the top sheet and slid slowly in the horizontal direction. At this time, the second and subsequent images from the top are fixed to the table so as not to move. The force required to slide the paper was measured with a spring alone. This measurement was repeated ten times in order from the top, and the average value of the force indicated by the spring was used as the sticking force (FIG. 6). When the sticking force was 1.5 N or less, it was set to a practical level. The evaluation criteria are as follows.

◎ ・ ・ ・ less than 0 ～ 1.0N ○ ・ ・ ・ 1.0N or more and 1.5N or less × ・ ・ ・ more than 1.5N

<Dispersion stability>
A fine particle dispersion having a solid content of 5% by mass was prepared, and the fluctuation range of the particle diameter after one month (that is, the median diameter (D ₅₀ ) of the fine particles contained in the resin fine particle dispersion immediately after preparation and one month later) The median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion was evaluated. The evaluation criteria are as follows.

◎ ・ ・ ・ Variation width 5μm or less ○ ・ ・ ・ Variation width 5μm to 10μm or less △ ・ ・ ・ Variation width 10μm to 15μm or less

<Image texture>
The image coated with the fine particle dispersion was confirmed by touch. The evaluation criteria are as follows.

◎ ・ ・ ・ less than 2 out of 50 people feel rough ○ ・ ・ ・ more than 3 to 5 people out of 50 feel rough △ ・ ・ ・ more than 6 out of 50 people within 9 People feel a rough feeling × ... More than 10 out of 50 people feel a rough feeling

[Example 2]
<Preparation of resin fine particle dispersion 2>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industrial Co., Ltd.) and swirl so that the median diameter (D ₅₀ ) is 8 μm. Resin fine particle dispersion 2 was obtained in the same manner except that the wind classifier (DS classifier manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 3]
<Preparation of resin fine particle dispersion 3>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Kogyo Co., Ltd.) and swirl so that the resin fine particles 3 having a median diameter (D ₅₀ ) of 10 μm are obtained. Resin fine particle dispersion 3 was obtained in the same manner except that the wind classifier (DS classifier manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 4]
<Preparation of resin fine particle dispersion 4>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and swirl so as to obtain a resin fine particle 4 having a median diameter (D ₅₀ ) of 15 μm. Resin fine particle dispersion 4 was obtained in the same manner except that the wind classifier (DS classifier manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 5]
<Preparation of resin fine particle dispersion 5>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and swirl so as to obtain a resin fine particle 5 having a median diameter (D ₅₀ ) of 30 μm. Resin fine particle dispersion 5 was obtained in the same manner except that the wind classifier (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 6]
<Preparation of resin fine particle dispersion 6>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and swirl so as to obtain a resin fine particle 6 having a median diameter (D ₅₀ ) of 45 μm. Resin fine particle dispersion 6 was obtained in the same manner except that the wind classifier (DS classifier: manufactured by Nippon Pneumatic Kogyo Co., Ltd.) was adjusted.

[Example 7]
<Preparation of resin fine particle dispersion 7>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industrial Co., Ltd.) and swirl so that the resin fine particles 7 having a median diameter (D ₅₀ ) of 50 μm are obtained. Resin fine particle dispersion 7 was obtained in the same manner except that the wind classifier (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 8]
<Preparation of resin fine particle dispersion 8>
In the production process of the resin fine particles 1 of Example 1, a jet mill type pulverizer (I-2 type mill: manufactured by Nippon Pneumatic Industry Co., Ltd.) and swirl so as to obtain a resin fine particle 8 having a median diameter (D ₅₀ ) of 55 μm. Resin fine particle dispersion 8 was obtained in the same manner except that the wind classifier (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 9]
<Preparation of resin fine particle dispersion 9>
In the manufacturing process of the resin fine particles 1 of Example 1, the PMMA resin is changed to polystyrene resin, and a jet mill type pulverizer (I-2 type mill: Japan) is made so that the resin fine particles 9 have a median diameter (D ₅₀ ) of 26 μm. The resin fine particle dispersion 9 was obtained in the same manner except that the pneumatic class (DS classifier: Nippon Pneumatic Kogyo Co., Ltd.) was adjusted.

[Example 10]
<Preparation of resin fine particle dispersion 10>
In the manufacturing process of the resin fine particles 1 of Example 1, the PMMA resin is changed to an acrylic resin, and a jet mill type pulverizer (I-2 type mill: Japan) so that the resin fine particles 10 having a median diameter (D ₅₀ ) of 20 μm is obtained. A resin fine particle dispersion 10 was obtained in the same manner except that the pneumatic class (DS classifier: manufactured by Nippon Pneumatic Kogyo Co., Ltd.) was adjusted.

[Example 11]
<Preparation of resin fine particle dispersion 11>
In the production process of the resin fine particles 1 of Example 1, the PMMA resin is changed to urea resin, and a jet mill type pulverizer (I-2 type mill: Japan) is made so that the resin fine particles 11 have a median diameter (D ₅₀ ) of 22 μm. A resin fine particle dispersion 11 was obtained in the same manner except that the pneumatic class (DS classifier: manufactured by Nippon Pneumatic Industry Co., Ltd.) was adjusted.

[Example 12]
<Preparation of resin fine particle dispersion 12>
In the production process of the resin fine particle 1 of Example 1, the PMMA resin is changed to a silicone resin, and a jet mill type pulverizer (I-2 type mill: Japan) is made so that the resin fine particle 12 has a median diameter (D ₅₀ ) of 11 μm. A resin fine particle dispersion 12 was obtained in the same manner except that the pneumatic classification (manufactured by Pneumatic Kogyo Co., Ltd.) and the wind classifying by swirling flow (DS classifier: manufactured by Nihon Pneumatic Kogyo Co., Ltd.) were adjusted.

[Example 13]
<Preparation of resin fine particle dispersion 13>
In the manufacturing process of the resin fine particles 1 of Example 1, the PMMA resin is changed to an epoxy resin, and a jet mill type pulverizer (I-2 type mill: Japan) is made so that the resin fine particles 13 have a median diameter (D ₅₀ ) of 21 μm. A resin fine particle dispersion 13 was obtained in the same manner except that the pneumatic classification (manufactured by Pneumatic Kogyo Co., Ltd.) and wind classifying by swirling flow (DS classifier: manufactured by Nippon Pneumatic Kogyo Co., Ltd.) were adjusted.

[Example 14]
<Preparation of resin fine particle dispersion 14>
In the production process of the resin fine particle 1 of Example 1, the PMMA resin is changed to a fluororesin, and a jet mill type pulverizer (I-2 type mill: Japan) is made so that the resin fine particle 14 has a median diameter (D ₅₀ ) of 22 μm. A resin fine particle dispersion 14 was obtained in the same manner except that the pneumatic class (DS classifier: Nippon Pneumatic Kogyo Co., Ltd.) was adjusted.

[Example 15]
<Preparation of resin fine particle dispersion 15>
In preparation of resin fine particle dispersion 1 of Example 1, except that 2.0 parts by mass of the cationic surfactant “Capron B-415” is changed to 2.0 parts by mass of the anionic surfactant “sodium lauryl sulfate”. In the same manner, resin fine particle dispersion 15 was obtained.

(Evaluation)
The fine particle dispersion applying unit shown in FIG. 4 was prepared. Specifically, two types, a first tank and a second tank, are prepared, and a tank (first tank) that supplies the dispersion liquid to the first fixing side (first side) during duplex printing. ) Is charged with 2 liters of the resin fine particle dispersion 15 dispersed with an anionic surfactant, and is dispersed with a cationic surfactant in a tank (second tank) for supplying the dispersion to the second side during double-sided printing. 2 L of the fine resin particle dispersion 1 was added. By doing so, the resin fine particle dispersion liquid applied to the first surface (“first surface side coating liquid” described in Table 2) becomes the resin fine particle dispersion liquid 15, and the resin fine particle dispersion liquid applied to the second surface. (“Second surface side coating solution” described in Table 2) is the resin fine particle dispersion 1.
Then, after confirming that the humidifying roller is wet, the humidifier is mounted on “bizhub PRESS C1070 (manufactured by Konica Minolta)” and a solid image (toner adhesion amount: 11.3 g / m ² ) in an NN environment. ) Was output on both sides (paper type: OK top coat paper (manufactured by Oji Paper Co., Ltd.) A3 157 g / m ² ). After 24 hours, evaluation was performed in the same manner as in Example 1.

[Example 12]
In Example 1, a solid image (toner adhesion amount: 11.3 g / m ² ) is printed on one side in an NN environment (described as “single side” in “print pattern” in Table 2), and changed to 100 sheets output. The same evaluation was performed in the same manner except that.

[Comparative Example 1]
The same evaluation was performed in the same manner as in Example 1 except that the resin fine particle dispersion 1 was not applied.

[Comparative Example 2]
The same evaluation was performed in the same manner as in Example 12 except that the resin fine particle dispersion 1 was not applied.

[Comparative Example 3]
The same evaluation was performed in the same manner as in Example 1 except that water (ion-exchanged water) was applied instead of the resin fine particle dispersion 1.

  The evaluation results in Examples 1 to 16 and Comparative Examples 1 to 3 are as shown in Table 2.

  From the above results, it was shown that the image forming apparatus of the present invention can suppress sticking of stacked sheets having an image on which toner is thermally fixed.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 110, 110A, 110B Fine particle dispersion application means 150, 160, Curl correction means 111A, 111B Humidification roller 112A, 112B Liquid supply roller 113A, 113B Control member 114A, 114B Liquid supply tank 118 Means to supply humidification liquid A Image forming unit B Fine particle dispersion applying unit C Bookbinding unit HR1 to HR3, HR21 to HR24 Paper transport path

Claims (11)

An image forming unit that forms an image by transferring toner containing at least a binder resin and a release agent onto a sheet, and a fixing device that fixes the image by heating and pressing the sheet on which the image is transferred An image forming apparatus having
An image forming apparatus comprising: a fine particle dispersion applying unit for applying a fine particle dispersion to the image fixed by the fixing device. 2. The image forming apparatus according to claim 1, wherein the specific gravity of the fine particles contained in the fine particle dispersion is in the range of 0.90 to 2.0 g / cm ³ . The image forming apparatus according to claim 1, wherein the specific gravity of the fine particles contained in the fine particle dispersion is in the range of 0.90 to 1.2 g / cm ³ .   The fine particles contained in the fine particle dispersion contain polystyrene resin, acrylic resin, methacrylic resin, urea resin, silicone resin, or epoxy resin. The image forming apparatus described in the item. 5. The image forming apparatus according to claim 1, wherein a median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is in a range of 10 to ₅₀ μm. . 6. The image forming apparatus according to claim 1, wherein a median diameter (D ₅₀ ) of the fine particles contained in the fine particle dispersion is in a range of 15 to 30 μm. . The fine particle dispersion applying unit has a humidifying roller for applying a humidifying liquid to the paper and a means for supplying the humidifying liquid to the humidifying roller;
The image forming apparatus according to claim 1, wherein the humidifying liquid is the fine particle dispersion. The fine particle dispersion application unit has a vertical paper conveyance path for guiding the paper downward or upward, a liquid supply unit, a liquid supply roller to which the humidifying liquid is supplied from the liquid supply unit,
The image forming apparatus according to claim 7, wherein the humidifying roller receives the humidifying liquid from the liquid supply roller.   The image forming apparatus according to claim 1, wherein the fine particle dispersion contains a surfactant. The fine particle dispersion applied to one surface of the paper on which the image has been fixed is a dispersion in which a cationic surfactant is dispersed;
10. The fine particle dispersion applied to a surface opposite to the one surface is a dispersion dispersed with an anionic surfactant. The image forming apparatus described in 1.   The image forming apparatus according to claim 1, wherein the binder resin contains a polyester resin.

Images