JP2010134261A - Resin composition for toner for electrostatic charge image development, toner for electrostatic charge image development, developer for electrostatic charge image development, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for toner for electrostatic charge image development, which suppresses chipping in a leading edge of an image caused by fluctuation in a charge amount of the toner, and to provide the toner for electrostatic charge image development, a developer for electrostatic charge image development, a process cartridge, and an image forming apparatus. <P>SOLUTION: The resin composition for a toner for an electrostatic charge image development contains a binder resin containing a vinyl resin to which polyolefin is grafted, and a release agent containing paraffin wax, wherein the dispersion value of the release agent in the resin composition for toner is ≤4%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner resin composition, an electrostatic charge image developing toner, an electrostatic charge image developing developer, a process cartridge, and an image forming apparatus.

  As an electrophotographic method, an electrostatic charge is applied to a photoconductive body (photosensitive drum, etc.), an electrostatic image is formed by irradiating the photoconductive body with various means, and then, In general, the latent image is developed and visualized using a fine powder called toner, and the toner powder image is transferred onto a recording medium such as paper and then fixed to obtain a printed matter. In this fixing step, the toner transferred onto the recording medium is melted by pressurization, heating, solvent vapor, light, etc., and fixed on the recording medium.

  In this fixing step, the toner transferred onto the recording medium is melted by pressurization, heating, solvent vapor, light, etc., and fixed on the recording medium. Here, the photofixing method in which the toner image is irradiated with strong light to melt the toner has attracted attention for the reasons described in the following items (1) to (3).

(1) Since it is non-contact fixing, image bleeding, dust and the like do not occur in the fixing process, and resolution is not deteriorated.
(2) Since no heating is required, there is no waiting time after the device power is turned on, and a quick start is possible.
(3) Fixing is possible regardless of the material and thickness of the recording paper, such as glued paper, preprinted paper, and paper of different thickness.

  On the other hand, attempts have been made to control the dispersibility of the wax added to the toner. For example, Patent Document 1 and Patent Document 2 disclose a toner using a graft polymer having a main chain of polyolefin and a side chain having a vinyl polymer chain in order to improve dispersibility of the release agent. Yes.

Patent Documents 3 and 4 disclose a technique of adding a vinyl polymer grafted with polyolefin to a toner in order to improve the dispersibility of a release agent.
Japanese Patent Laid-Open No. 2000-075549 JP 2000-305319 A JP 2002-169329 A Japanese Patent Laid-Open No. 2005-10679

  An object of the present invention is to provide a toner resin composition for developing an electrostatic charge image in which the leading edge chipping of an image due to variation in charge amount in the toner is suppressed.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1
A binder resin containing a vinyl-based resin grafted with polyolefin, and a release agent containing paraffin wax,
The toner resin composition for developing an electrostatic charge image, wherein a dispersion value of the release agent in the toner resin composition is 4% or less.

The invention according to claim 2
The resin composition for an electrostatic charge image developing toner according to claim 1, further comprising an infrared absorber.

The invention according to claim 3
The resin composition for toner for developing electrostatic images according to claim 1, wherein the paraffin wax has a melting point of 95 ° C. or higher and 114 ° C. or lower.

The invention according to claim 4
4. The electrostatic charge image developing toner resin composition according to claim 1, wherein the release agent contains a polyethylene wax having a weight average molecular weight of 8000 to 23,000. 5.

The invention according to claim 5
A colorant, wherein the colorant is C.I. I. 5. The resin composition for toner for developing an electrostatic charge image according to claim 1, which is CI Pigment Yellow 180. 5.

The invention according to claim 6
6. An electrostatic charge image developing toner obtained by pulverizing the electrostatic charge image developing toner resin composition according to any one of claims 1 to 5.

The invention according to claim 7 provides:
A binder resin containing a vinyl-based resin grafted with polyolefin, and a release agent containing paraffin wax,
The toner for developing an electrostatic charge image has a dispersion value of the release agent in the toner of 5% or less.

The invention according to claim 8 provides:
The electrostatic image developing toner according to claim 7, further comprising an infrared absorber.

The invention according to claim 9 is:
The toner for developing an electrostatic charge image according to claim 7, wherein the paraffin wax has a melting point of 95 ° C. or higher and 114 ° C. or lower.

The invention according to claim 10 is:
10. The electrostatic image developing toner according to claim 7, wherein the release agent contains a polyethylene wax having a weight average molecular weight of 8000 to 23000. 11.

The invention according to claim 11 is:
A colorant, wherein the colorant is C.I. I. 11. The electrostatic charge image developing toner according to claim 7, which is CI Pigment Yellow 180. 11.

The invention according to claim 12
An electrostatic image developing developer comprising at least the electrostatic image developing toner according to any one of claims 6 to 11.

The invention according to claim 13 is:
A process cartridge comprising a developer holder and containing the developer for developing an electrostatic image according to claim 12.

The invention according to claim 14 is:
A latent image carrier,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member;
Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image;
Transfer means for transferring the toner image formed on the latent image holding member onto a transfer target;
An image forming apparatus, comprising: a fixing unit that fixes the toner image transferred onto the transfer target member to the transfer target member, wherein the developer is the electrostatic charge image developing developer according to claim 12. It is.

The invention according to claim 15 is:
The image forming apparatus according to claim 14, wherein the process speed is 360 mm / s or more.

The invention according to claim 16 provides:
The developing means includes a developer holder;
The image forming apparatus according to claim 14, wherein a movement direction of the surface of the latent image holding member and a movement direction of the surface of the developer holding member at a position where the toner image is formed are opposite to each other. is there.

According to the first aspect of the present invention, compared to the case where the dispersion value of the release agent in the toner resin composition is not taken into account, the leading edge of the image due to the variation in the charge amount in the toner is suppressed. The
According to the invention which concerns on Claim 2, uneven distribution of an infrared absorber is suppressed.
According to the third aspect of the present invention, compared to the case where the melting point of the paraffin wax is not taken into consideration, the leading edge defect of the image due to the variation in the charge amount in the toner is further suppressed, and the toner fixing property is improved.
According to the fourth aspect of the invention, compared to the case where the release agent does not contain the polyethylene wax, the leading edge chipping of the image due to the variation in the charge amount in the toner is further suppressed, and the toner fixability is improved. improves.
According to the invention of claim 5, C.I. I. Compared to the case where Pigment Yellow 180 is not included, the color developability of yellow toner is improved.

According to the sixth aspect of the invention, compared to the case where the dispersion value of the release agent in the toner resin composition is not taken into consideration, the leading edge chipping of the image due to the variation in the charge amount in the toner is suppressed.
According to the seventh aspect of the invention, compared to the case where the dispersion value of the release agent in the toner is not taken into account, the leading edge of the image due to the variation in the charge amount in the toner is suppressed.
According to the invention which concerns on Claim 8, uneven distribution of an infrared absorber is suppressed.
According to the ninth aspect of the invention, compared to the case where the melting point of the paraffin wax is not taken into consideration, the leading edge defect of the image due to the variation in the charge amount in the toner is further suppressed, and the toner fixability is improved.
According to the tenth aspect of the invention, compared to the case where the release agent does not contain the polyethylene wax, chipping at the leading edge of the image due to variation in the charge amount in the toner is further suppressed, and the toner fixability is improved. improves.
According to the invention of claim 11, C.I. I. Compared to the case where Pigment Yellow 180 is not included, a yellow toner having high color developability can be obtained.

According to the twelfth aspect of the present invention, compared to the case where the dispersion value of the release agent in the toner resin composition or in the toner is not taken into consideration, the leading edge of the image due to the variation in the charge amount in the toner is suppressed. The
According to the thirteenth aspect of the present invention, compared to the case where the dispersion value of the release agent in the toner resin composition or in the toner is not taken into consideration, the leading edge of the image due to the variation in the charge amount in the toner is suppressed. The
According to the fourteenth aspect of the present invention, compared to the case where the dispersion value of the release agent in the toner resin composition or in the toner is not taken into consideration, the leading edge of the image due to the variation in the charge amount in the toner is suppressed. The
According to the fifteenth aspect of the present invention, even when the process speed is high, chipping at the leading edge of the image due to the variation in the charge amount of the toner is suppressed but suppressed.
According to the sixteenth aspect of the present invention, even when the moving direction of the latent image holding member surface and the moving direction of the developer holding member surface are opposite to each other, the leading edge of the image is lost due to the variation in the charge amount of the toner. Is suppressed.

Hereinafter, the present invention will be described in detail.
<Resin composition for toner for developing electrostatic image>
The electrostatic charge image developing toner resin composition of the present embodiment (hereinafter sometimes simply referred to as “toner resin composition”) is a vinyl-based resin grafted with polyolefin (hereinafter referred to as “graft polymer”). And a release agent containing a paraffin wax, and a dispersion value of the release agent in the toner resin composition is 4% or less. To do.

Here, the dispersion value of the release agent in the toner resin composition (hereinafter sometimes referred to as “wax dispersion value in the composition”) is defined as a value obtained as follows. Specifically, first, the resin composition for toner is cut into a thickness of 10 μm using a diamond cutter (manufactured by DIATOME: Hist for light microscopy) to obtain a measurement sample. Next, the measurement sample is photographed with a transmission electron microscope (manufactured by Hitachi, Ltd .: HF-3300) at 500 times to obtain an image corresponding to a sample measurement surface of 20 μm × 20 μm. Furthermore, using the attached image analysis software, the sum of the area of the part where the release agent locally exists as a lump with respect to the area of the entire image obtained (hereinafter sometimes referred to as “total area”) ( Hereinafter, the ratio of “wax lump area” may be determined and used as the wax dispersion value in the composition. That is, the wax dispersion value in the composition is obtained by the following formula. When measuring the dispersion value of the release agent in the toner (hereinafter sometimes referred to as “wax dispersion value in the toner”), toner particles embedded in an epoxy resin or the like are used, and the above composition is used. It is measured by the same method as the measurement of the wax dispersion value in the product. For this reason, the sample measurement surface may include a portion that is not a toner (a portion such as a resin). In this case, the area of the image of the toner portion is “total area”.
Formula: Wax dispersion value in composition (%) = wax lump area / total area × 100

  If the content of the release agent in the toner resin composition is constant, the better the dispersibility of the release agent, the smaller the portion recognized as the wax lump area. The wax dispersion value becomes smaller. On the other hand, when the dispersibility of the release agent is poor and the portion recognized as the wax lump area is large, the value of the wax dispersion value in the composition becomes large.

  In the present embodiment, since the toner resin composition has the above-described configuration, chipping due to variations in the charge amount of the toner is suppressed. The reason is not clear, but is presumed as follows.

  In a toner to which a release agent is added in order to obtain high fixing performance, particularly severe conditions such as high temperature and high humidity (room temperature 30 ° C., humidity 90%) depend on the characteristics and addition amount of the added release agent. Under the environment, there may be an image quality abnormality such as chipping at the tip (part of the boundary line between the image portion and the non-image portion, in particular, chipping of an image generated at a side perpendicular to the traveling direction of the latent image holding member). As a cause of the image quality abnormality, uneven distribution due to a lump of the release agent in the toner can be considered.

  In particular, when a toner is produced by a kneading pulverization method or the like, if the release agent is unevenly distributed as a lump in the resin composition for toner that is a pre-stage of the pulverization process, the toner prepared by pulverization is separated for each particle. In particular, if there is a wax lump (releasing agent lump), the portion tends to remain near the surface of the toner even if pulverized, so that the toner is near the surface compared to other toners. The amount of release agent present will increase relatively. As a result, the toner charge amount may vary. If the charge amount of the toner varies, the behavior varies depending on the toner particles in the development process and transfer process using an electric field. More specifically, at the leading end portion of the latent image of the latent image holding member, the force due to the pressing of the charge from the non-image portion is stronger than the solid portion, so that the toner is easily developed. The variation of is not likely to be a problem. However, in the transfer process, the toner in which the wax lump remains is low in charge amount, and unlike other toners, it is difficult to transfer because of the influence of the electric field. Similarly, toner is easily developed even in image formation in a high temperature and high humidity environment, so the influence of variations in the charge amount in the development process is small, but in the transfer process, toner with a low charge amount tends to be difficult to transfer, Since the influence due to the variation in the charge amount is large, it is considered that the influence on the formed image becomes large as a result.

However, when the binder resin containing the graft polymer is used as in the present embodiment and paraffin wax is used as a release agent, the dispersibility of the paraffin wax in the toner resin composition is improved. Therefore, it is presumed that the variation in the charge amount in the toner is suppressed, and the image quality abnormality such as chipping at the tip is suppressed.
Further, it was produced by pulverizing by controlling the release agent dispersibility in the toner resin composition (wax dispersion value in the composition) and the release agent dispersibility in the toner (wax dispersion value in the toner). Since variation in composition of toner particles is suppressed and variation in charge amount in toner is suppressed, it is estimated that chipping is suppressed even when an image is formed at a high process speed.
As a means for controlling the dispersibility of the release agent in the toner resin composition, as described later, for example, a method of controlling the content ratio of the graft polymer and the paraffin wax contained in the toner resin composition Is mentioned.

In addition, in a resin composition for a toner containing an infrared absorbent, such as a resin composition for a toner for photofixing or an infrared absorbing toner, the infrared absorbent may be unevenly distributed along with the uneven distribution of the release agent. Specifically, for example, when using an infrared absorber having high affinity with the release agent, it is considered that a large amount of the infrared absorber is collected at a location where the release agent exists locally as a lump. On the other hand, when an infrared absorber having a low affinity with the release agent is used, it is considered that a large amount of the infrared absorber is collected at a location where the concentration of the release agent is low. When such a resin composition for a toner in which an infrared absorbent is unevenly distributed is pulverized, the amount of the infrared absorbent contained in the produced toner particles varies, so that the effect of the infrared absorbent itself varies (for example, light Uneven fixing in the case of fixing toner may occur. In addition, when the infrared absorbent easily absorbs water, the variation in charge amount may be further increased.
However, in this embodiment, since the release agent is well dispersed in the toner resin composition, uneven distribution of the infrared absorber is suppressed, and uneven fixing and variations in charge amount as described above are suppressed. It is guessed.

  That is, for example, even when adding a release agent in an amount necessary for improving the fixing property of the toner, the graft dispersion and the paraffin wax are used as in the present embodiment, and the wax dispersion value in the composition is set to the above value. If it is within the range, the release agent is well dispersed and the amount of localized release agent is small, so that chipping due to variation in the charge amount in the toner is suppressed.

  As described above, the wax dispersion value in the composition is 4% or less, preferably 3% or less, and more preferably 2% or less. The wax dispersion value in the composition and the wax dispersion value in the toner are recognized by the above method because they exist locally as a lump of the release agent among the release agents contained in the toner resin composition or in the toner. Since the ratio of the region is shown, the lower the wax dispersion value in the composition, the better the dispersion of the release agent, which is desirable. On the other hand, for example, when the content of the release agent in the toner resin composition is 7% by mass, the actual lower limit of the wax dispersion value in the composition is 0.01%, and the wax dispersion in the composition is It is very difficult to make the value less than 0.01%.

  Hereinafter, each composition component will be described.

[Binder resin]
The binder resin is required to contain a graft polymer, and may contain a polyester resin or other resin as necessary. The binder resin may have a graft polymer as a main component, but is preferably a resin in which another resin (for example, a polyester resin) is a main component and a graft polymer is added thereto. The “main component” refers to a component containing 50% by mass or more based on the whole.

-Graft polymer-
The graft polymer is a graft polymer having a polyolefin chain in the side chain of the vinyl resin of the main skeleton.

The vinyl resin of the main skeleton is preferably a copolymer obtained by copolymerization using a styrene monomer and an alkyl ester of an unsaturated carboxylic acid (hereinafter sometimes referred to as “ester monomer”).
Specific examples of the styrenic monomer include styrene and alkylstyrene (for example, α-methylstyrene, p-methylstyrene, etc.), and these may be used alone. Two or more kinds may be used in combination. Of these, styrene is most preferred.
Specific examples of the unsaturated carboxylic acid constituting the ester monomer include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, diacrylic acid, dimethacrylic acid, and the like. Of these, acrylic acid and methacrylic acid are particularly preferred. Examples of the ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate.

When a polyester resin is used in addition to the graft polymer, an unsaturated nitrile monomer, an α, β-unsaturated carboxylic acid, etc. are further used in combination as a monomer used for the synthesis of the vinyl resin of the main skeleton. May be.
Specific examples of the unsaturated nitrile monomer include acrylonitrile and methacrylonitrile.
Specific examples of the α, β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, and maleic acid.

  As the vinyl resin of the main skeleton, among the copolymers of the above monomers, a styrene-acrylonitrile-butyl acrylate copolymer, a styrene-butyl acrylate copolymer, and a styrene-butyl acrylate-acrylic acid copolymer are preferable. In place of acrylate and acrylic acid, methacrylate or methacrylic acid may be used.

  The addition amount of the styrene monomer in the whole monomer used for the synthesis of the vinyl resin of the main skeleton is desirably 50% by mass to 95% by mass, the addition amount of the ester monomer is desirably 5% by mass to 50% by mass, and the unsaturated nitrile. The addition amount of the monomer and the α, β-unsaturated carboxylic acid is preferably 3% by mass or more and 20% by mass or less.

Known polyolefins are used as the polyolefin to be graft-polymerized to the main skeleton vinyl resin, and preferably contain at least one of polypropylene and polyethylene.
The amount of polyolefin to be graft polymerized to the vinyl resin of the main skeleton is preferably 10 parts by mass or more and 150 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the vinyl resin of the main skeleton. 30 parts by mass or more and 90 parts by mass or less is more preferable.

Examples of the method for synthesizing the graft polymer include the following methods. In particular,
For example, the vinyl resin that is the main skeleton is synthesized in advance so that an unsaturated double bond remains, and then the unsaturated double bond is polymerized together with another polymerizable monomer. In addition, instead of other polymerizable monomers, a multimer that has progressed to some extent may be reacted with an unsaturated double bond of the main skeleton.

  The content of the graft polymer in the binder resin is preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 10% by mass or less, and further preferably 1% by mass or more and 5% by mass or less. preferable.

As described above, the wax dispersion value in the composition is controlled by controlling the content of the graft polymer contained in the toner resin composition. The graft polymer content varies depending on the type of graft polymer.
Specifically, for example, when a graft polymer obtained by graft-polymerizing polyethylene wax and polypropylene wax to a styrene-acrylonitrile-butyl acrylate copolymer is used, the graft polymer content in the toner resin composition is 0.00. 5 mass% or more and 10 mass% or less are preferable, 0.8 mass% or more and 8 mass% or less are more preferable, and 1 mass% or more and 7 mass% or less are especially preferable.
Further, for example, when a graft polymer obtained by graft polymerizing polyethylene wax to polyester is used, the content of the graft polymer in the toner resin composition is preferably 0.5% by mass to 10% by mass, and preferably 1% by mass. The content is more preferably 5% by mass or less and particularly preferably 2% by mass or more and 5% by mass or less.

  Further, the content of the graft polymer contained in the toner resin composition is preferably from 1 to 5 times, more preferably from 2 to 5 times the content of the release agent contained in the toner resin composition. Preferably, it is more preferably 2.5 times or more and 5 times or less.

  The glass transition temperature (Tg) of the graft polymer is preferably in the range of 40 ° C. to 80 ° C., and the weight average molecular weight of the graft polymer vinyl resin is preferably 3000 to 50000.

-Polyester resin-
The binder resin preferably contains polyester in addition to the graft polymer. Further, as described above, the binder resin preferably contains a polyester resin as a main component and the graft polymer as an additive.
The polyester resin is obtained by condensation polymerization of a carboxylic acid component and an alcohol component, and conventionally known divalent or trivalent or higher carboxylic acid and divalent or trivalent or higher alcohol are used.

Specific examples of the divalent carboxylic acids include aliphatic dicarboxylic acids such as maleic acid, fumaric acid, succinic acid, adipic acid, malonic acid, sebacic acid, mesaconic acid, dodecenyl (anhydrous) succinic acid, and anhydrides thereof. Products and lower alkyl esters; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, toluene dicarboxylic acid, naphthalenedicarboxylic acid, and their anhydrides and lower alkyl esters; hydrocarbon groups having 4 to 35 carbon atoms in the side chain Or an alkenyl (anhydrous) succinic acid [specifically, dodecenyl (anhydrous) succinic acid, pentadodecenyl (anhydrous) succinic acid, etc.] or an anhydride or a lower alkyl ester thereof.
Specific examples of the trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, 1,2,4-cyclohexanetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid, 1,2,4. -Naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,2,7,8-octanetetracarboxylic acid, or their acid anhydrides and lower alkyl esters. These may be used individually by 1 type and may use 2 or more types together.

On the other hand, as the dihydric alcohol, diols include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1, C2-C12 alkylene glycol such as 5-pentanediol and 1,6-hexanediol, alkylene ether glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, 1 , 4-cyclohexanedimethanol, hydrogenated bisphenol A and the like alicyclic diols having 6 to 30 carbon atoms, bisphenols such as bisphenol A, bisphenol F and bisphenol S, and bisphenol Alkylene oxide 2-8 moles adducts of the kind can be mentioned.
Further, as trihydric or higher alcohols, sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1 , 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane and other aliphatic polyhydric alcohols having 3 to 20 carbon atoms, Aromatic polyhydric alcohols having 6 to 20 carbon atoms such as 1,3,5-trihydroxylmethylbenzene and these alkylene oxide adducts are used.

The content of the polyester resin contained in the binder resin is preferably 60% by mass to 99.5% by mass, more preferably 70% by mass to 99% by mass, and particularly preferably 80% by mass to 99% by mass. .
The content of the polyester resin contained in the toner resin composition is preferably 50% by mass to 95% by mass, more preferably 60% by mass to 95% by mass, and particularly preferably 70% by mass to 95% by mass. .

  The Tg (glass transition temperature) of the polyester resin is preferably in the range of 40 to 80 ° C. The weight average molecular weight of the polyester resin is preferably 5000 to 100,000.

-Other resins-
Other resins include copolymers of styrene and acrylic acid or methacrylic acid, polyvinyl chloride resin, phenol resin, acrylic resin, methacrylic resin, polyvinyl acetate, silicone resin, polyurethane, polyamide resin, furan resin, epoxy resin , Xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin, polyether polyol resin and the like.
The other resin may be contained in the binder resin as a main component, or may be added as a third component to the polyester resin that is the main component.

[Release agent]
The release agent contains paraffin wax, and may contain polyethylene wax and other release agents as necessary.

-Paraffin wax-
As the paraffin wax, those having a melting point of 95 ° C. or higher and 114 ° C. or lower are preferably used, and those having a melting point of 100 ° C. or higher and 114 ° C. or lower are more preferable. By using a paraffin wax having a melting point in the above range, chipping at the leading edge of the image due to variations in the charge amount in the toner is further suppressed, and the toner fixability is improved.
The content of the paraffin wax contained in the resin composition for toner is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, and further preferably 3% by mass to 10% by mass. . When the content of the paraffin wax contained in the toner resin composition is within the above range, both the control of chipping at the leading edge of the image and good fixability can be achieved.

-Polyethylene wax-
The release agent may contain polyethylene wax in addition to paraffin wax, and preferably contains polyethylene wax having a weight average molecular weight of 8000 to 23,000. The weight average molecular weight of the polyethylene wax is preferably from 8000 to 23,000, more preferably from 10,000 to 20,000, and even more preferably from 12,000 to 18,000.
The melting point of the polyethylene wax is preferably 90 ° C. or higher and 115 ° C. or lower, more preferably 95 ° C. or higher and 110 ° C. or lower, and further preferably 100 ° C. or higher and 110 ° C. or lower.
The content of the polyethylene wax contained in the toner resin composition is preferably from 0.5% by weight to 15% by weight, more preferably from 1% by weight to 10% by weight, and more preferably from 2% by weight to 8% by weight. Further preferred.

-Other mold release agents-
Other release agents include, for example, ester wax, polypropylene or a copolymer of polyethylene and polypropylene, polyglycerin wax, microcrystalline wax, carnauba wax, sazol wax, montanic ester wax, deoxidized carnauba wax, palmitic acid. , Stearic acid, montanic acid, blandic acid, eleostearic acid, valinalic acid and other unsaturated fatty acids, stearic alcohol, aralkyl alcohol, behenyl alcohol, carnauvyl alcohol, seryl alcohol, melyl alcohol, or even longer chain alkyls Saturated alcohols such as long-chain alkyl alcohols having a group; polyhydric alcohols such as sorbitol; fats such as linoleic acid amide, oleic acid amide, and lauric acid amide Amides; saturated fatty acid bisamides such as methylenebisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, hexamethylene bisstearic acid amide, ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N Unsaturated fatty acid amides such as' -dioleoyl adipic acid amide and N, N'-dioleyl sebacic acid amide; aromatic systems such as m-xylenebisstearic acid amide and N, N'-distearyl isophthalic acid amide Bisamides; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate, magnesium stearate (generally called metal soap); vinyl monomers such as styrene and acrylic acid in aliphatic hydrocarbon waxes Gra Waxes were collected by reduction; fatty acids and partial esters of polyhydric alcohols such as behenic acid monoglyceride; and methyl ester compounds having a hydroxyl group obtained by and hydrogenated vegetable oils and the like.

The other mold release agent is preferably a material that exhibits an endothermic peak by DSC measurement (differential scanning calorimetry) at 50 ° C. or more and 160 ° C. or less. In the DSC measurement, it is preferable to measure with a differential scanning calorimeter of high accuracy internal heat input compensation type from the measurement principle.
The total content of the release agent contained in the toner resin composition is preferably 0.5% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass or less. More preferably, it is at least 8% by mass. When the content of the entire release agent contained in the toner resin composition is within the above range, good fixability can be obtained.

[Colorant]
The toner resin composition of the present embodiment may contain a colorant as necessary.
Examples of the colorant used in the cyan toner resin composition include C.I. I. Pigment Blue 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 13, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 17, 17, 23, 60, 65, 73, 83, 180, C.I. I. Vat cyan 1, 3 and 20, etc., bitumen, cobalt blue, alkali blue lake, phthalocyanine blue, metal-free phthalocyanine blue, partially chlorinated phthalocyanine blue, fast sky blue, indanthrene blue BC cyan pigment, C.I. I. And cyan dyes such as solvent cyan 79 and 162.

  Examples of the colorant used in the magenta toner resin composition include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 15, 15, 16, 17, 18, 19, 21, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 50, 51, 52, 53, 54, 55, 57, 58, 60, 63, 64, 68, 81, 83, 87, 88, 89, 90 112, 114, 122, 123, 163, 184, 202, 206, 207, and 209, pigment violet 19 magenta pigments, C.I. I. Solvent Red 1, 3, 8, 23, 24, 25, 27, 30, 30, 49, 81, 82, 83, 84, 100, 109, 121, C . I. Disper thread 9, C.I. I. Basic Red 1, 2, 9, 9, 13, 14, 15, 17, 17, 18, 22, 23, 24, 27, 29, 32, 34, the same 35, 36, 37, 38, 39, 40, etc. Magenta dyes, etc., Bengala, Cadmium Red, Lead Tan, Mercury Sulfide, Cadmium, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red, Calcium Salt, lake red D, brilliant carmine 6B, eosin lake, rotamin lake B, alizarin lake, brilliant carmine 3B and the like.

  Examples of the colorant used in the yellow toner resin composition include C.I. I. And CI pigment yellow 2, 3, 15, 16, 17, 74, 97, 180, 185, 139, and the like. Among these, C.I. I. It is desirable to use CI Pigment Yellow 180 from the viewpoint of further improving the color developability of the yellow toner. In particular, the yellow pigment is likely to form an aggregate itself, and it is assumed that the dispersion deteriorates due to the presence of a lump of the release agent.

  Examples of the colorant used for the black toner resin composition include carbon black, activated carbon, titanium black, magnetic powder such as iron powder, magnetite, and ferrite, and nonmagnetic powder containing Mn. Further, a resin composition for a pigment black toner in which yellow, magenta, cyan, red, green, and blue pigments are mixed may be used.

  The content of the colorant in the toner resin composition is preferably 1.5% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 15% by mass or less.

[Charge control agent]
The resin composition for toner of this embodiment may contain a charge control agent.
The charge control agent is not particularly limited, and known ones may be used depending on the purpose. For example, as a positively chargeable charge control agent, nigrosine dye, tributylbenzylammonium-1-hydroxy-4-naphthosulfonate , Quaternary ammonium salts such as tetrabutylammonium tetrafluoroborate, and onium salts such as phosphonium salts that are analogs thereof, and lake pigments thereof; triphenylmethane dyes; metal salts of higher fatty acids; dibutyltin oxide, dioctyltin Examples include diorganotin oxides such as oxide and dicyclohexyltin oxide; diorganotin borates such as dibutyltin borate; guanidine compounds, imidazole compounds, and aminoacrylic resins. Of these, nigrosine dyes and quaternary ammonium salts are particularly preferably used. These charge control agents may be used individually by 1 type, and may use 2 or more types together.
The content of the charge control agent in the toner resin composition is preferably 0.5% by mass or more and 5% by mass or less.

[Infrared absorber]
In the case where the toner resin composition of the present embodiment is for a light fixing toner (a toner used in an image forming apparatus using a light fixing method) or an infrared absorbing toner, an infrared ray is contained in the toner resin composition. You may contain an absorber.
As the infrared absorber, known infrared absorbers are used, for example, cyanine compounds, merocyanine compounds, benzenethiol metal complexes, mercaptophenol metal complexes, aromatic diamine metal complexes, diimonium compounds, aminium compounds, nickel complexes. Compounds, phthalocyanine compounds, anthraquinone compounds, naphthalocyanine compounds, and the like.

  Specific infrared absorbers include nickel metal complex infrared absorbers (Mitsui Chemical Co., Ltd .: SIR-130, SIR-132), bis (dithiobenzyl) nickel (Midori Chemical Co., Ltd .: MIR-101), bis [ 1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (manufactured by Midori Chemical Co., Ltd .: MIR-102), tetra-n-butylammonium bis (cis-1,2-diphenyl-1, 2-Ethylenedithiolate) nickel (Midori Chemical Co., Ltd .: MIR-1011), tetra-n-butylammonium bis [1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (Midori Chemical) Manufactured by MIR-1021), bis (4-tert-1,2-butyl-1,2-dithiophenolate) nickel-tetra-n Butylammonium (manufactured by Sumitomo Seika Co., Ltd .: BBDT-NI), cyanine infrared absorber (Fuji Film Co., Ltd .: IRF-106, IRF-107), cyanine infrared absorber (manufactured by Yamamoto Kasei Co., Ltd., YKR2900), aminium, Diimonium-based infrared absorber (manufactured by Nagase Chemtech: NIR-AM1, IM1), imonium compound (manufactured by Nippon Carlit: CIR-1080, CIR-1081), aminium compound (manufactured by Nippon Carlit: CIR-960, CIR-961) ), Anthraquinone compounds (Nippon Kayaku Co., Ltd .: IR-750), aminium compounds (Nippon Kayaku Co., Ltd .: IRG-002, IRG-003, IRG-003K), polymethine compounds (Nippon Kayaku Co., Ltd .: IR-820B), a diimonium compound (Nippon Kayaku Co., Ltd .: IRG-022, I G-023), dianine compound (Nippon Kayaku Co., Ltd .: CY-2, CY-4, CY-9), soluble phthalocyanine (Nippon Shokubai Co., Ltd .: TX-305A), naphthalocyanine (Yamamoto Kasei Co., Ltd .: YKR5010), Sanyo Dye Co., Ltd .: Sample 1), inorganic material system (Shin-Etsu Chemical Co., Ltd .: Ytterbium UU-HP, Sumitomo Metals Co., Ltd .: Injumetin Oxide) and the like. Of these, diimonium, aminium, naphthalocyanine, and cyanine are preferable for photofixing.

  As described above, when an infrared absorber having a high affinity with the release agent is used, if the release agent in the toner resin composition is unevenly distributed, the infrared absorber is also unevenly distributed along with the unevenness as described above. Uneven fixing may occur. Specific examples of the infrared absorber having a high affinity with the release agent include an aminium compound, a naphthalocyanine compound, and an imonium compound.

  The addition amount of the infrared absorber is preferably in the range of 0.01% by mass to 5% by mass, more preferably in the range of 0.1% by mass to 5% by mass in the toner resin composition. When the addition amount is less than 0.01% by mass, the toner may not be fixed in the case of photofixing using a flash. On the other hand, if it exceeds 5% by mass, the color of the toner may become cloudy.

[Other internal additives]
The resin composition for toner may further contain other internal additives. Examples of other internal additives include magnetic materials.
Specific examples of the magnetic material include iron powder, magnetite, and ferrite, and other known white magnetic powder (for example, manufactured by Nittetsu Mining Co., Ltd.) can also be used.

[Method for Producing Toner Resin Composition]
The resin composition for toner according to the exemplary embodiment is manufactured in a process of manufacturing a toner by a known toner manufacturing method such as a pulverization method, and is in a state before passing through the pulverization process.
Examples of the method for producing the resin composition for toner include the following methods. Specifically, for example, after mixing components such as the above-described binder resin, release agent, charge control agent, colorant, and infrared absorber, the above materials are melt-kneaded using a kneader, an extruder, or the like. Thus, a resin composition for toner is obtained.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image of the present embodiment has a binder resin containing a vinyl resin grafted with polyolefin and a release agent containing paraffin wax, and the dispersion of the release agent in the toner The value is 5% or less.

Here, the dispersion value of the release agent in the toner (wax dispersion value in the toner) is defined as a value obtained as follows.
Specifically, if the sample is a resin composition for toner, a kneaded product (toner resin composition) is used as it is. If the sample is a toner, it is dispersed in a resin in which the toner is not substantially dissolved and dispersed.
Examples of the resin used for the production of the measurement sample include a resin that cures without heating, such as an epoxy resin.

Next, the measurement sample was cut out using a diamond cutter (manufactured by DIATOME: Hist for light microscopy) as described above, photographed with a transmission electron microscope, and the wax dispersion value in the toner was calculated from the obtained image by the following formula. Ask.
Formula: Wax dispersion value in toner (%) = wax lump area / total toner area × 100

Similarly to the wax dispersion value in the composition, the wax dispersion value in the toner is such that when the content of the release agent in the toner is constant, the better the dispersibility of the release agent, the more the wax dispersion value in the toner is The smaller the wax dispersibility is, the larger the wax dispersion value in the toner is.
When the toner resin composition for which the wax dispersion value in the composition was measured was pulverized to prepare a toner, and the wax dispersion value in the toner of the obtained toner was measured, the wax dispersion value in the toner was the wax in the composition. The value is larger than the variance value.

In the present embodiment, since the toner has the above-described configuration, chipping at the tip due to variation in the charge amount of the toner is suppressed. The reason is not clear, but it is presumed that the reason is the same as that of the resin composition for toner.
Further, for example, in a toner containing an infrared absorber such as a toner for photofixing, fixing unevenness and variation in charge amount due to uneven distribution of the infrared absorber are suppressed as in the toner resin composition containing an infrared absorber. The

  As described above, the wax dispersion value in the toner is 5% or less, preferably 4% or less, more preferably 3% or less. Similar to the wax dispersion value in the composition, the lower the wax dispersion value in the toner, the better the dispersion of the release agent. On the other hand, for example, when the content of the release agent in the toner is 7% by mass, the practical lower limit of the wax dispersion value in the toner is 0.01%, and the wax dispersion value in the toner is 0.01%. It is very difficult to make it less than.

  Among the toner composition components, the binder resin, the release agent, the colorant, the charge control agent, and the infrared absorber are the same as the respective composition components of the toner resin composition described above, and thus the description thereof is omitted. .

[Toner Production Method]
The toner is produced by a known toner manufacturing method such as a pulverization method.
When using the pulverization method, for example, a toner resin composition is prepared as described above, and the obtained toner resin composition is coarsely pulverized, then finely pulverized with a jet mill or the like, and then used with an air classifier. Then, toner particles having a target particle diameter are obtained.
Further, if necessary, an external additive such as silica is added to the toner particles and sufficiently mixed by a mixer such as a Henschel mixer to obtain an externally added toner.

Examples of the external additive include inorganic particles, metal salts of higher fatty acids represented by zinc stearate, and organic particles.
Examples of inorganic particles include silica powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide. , Cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, etc., including at least one of silica, titanium oxide, and alumina. It is particularly preferable.
Examples of the organic particles include vinyl polymers such as styrene polymers, (meth) acrylic polymers, and ethylene polymers, and various polymers such as ester, melamine, amide, and allyl phthalate. Examples thereof include fluorine-based polymers such as vinylidene fluoride and organic particles composed of higher alcohols.

  The ratio of the external additive externally added to the toner particles before external addition is preferably in the range of 0.01 parts by mass to 5 parts by mass with respect to 100 parts by mass of the toner particles before external addition, and 0.1 parts by mass or more. The range of 3.0 parts by mass or less is more preferable.

[Toner characteristics]
The volume average particle size of the toner particles before external addition is preferably 4 μm or more and 12 μm or less.
As a method for measuring the volume average particle diameter of the toner particles, for example, a Coulter Multisizer-II type is used. Specifically, 0.5 to 50 mg of a measurement sample is added to a surfactant as a dispersant, and this is added to 100 to 150 ml of an electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for 1 minute, and the particle size is 2.0 to 60 μm using the Coulter counter TA-II type with an aperture having an aperture diameter of 100 μm. The particle size distribution of the particles in the range is measured. The number of particles to be measured is 50,000. For the particle size range (channel) obtained by dividing the obtained particle size distribution, the volume cumulative distribution is subtracted from the small particle size side, and the particle size at 50% cumulative is taken as the volume average particle size.

<Developer for developing electrostatic image>
Next, a developer for developing an electrostatic image containing the toner (hereinafter sometimes simply referred to as “developer”) will be described. The developer may be either a one-component developer composed of the toner or a two-component developer composed of a carrier and a toner. Hereinafter, the case where the developer is a two-component developer will be described in detail.

[Career]
There is no restriction | limiting in particular as a carrier which can be used for the said two-component developer, A well-known carrier is used. For example, a resin-coated carrier having a resin coating layer on the surface of the core material 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.
Ferrite, magnetite, iron powder, etc. are used as the material of the magnetic particles that will be the main body (core material) of the carrier.

  The volume average particle diameter of the carrier is preferably 20 to 100 μm, more preferably 30 to 80 μm. The resin-coated carrier can be obtained by coating the core material (core material) with a resin by a known method such as a spray drying method using a fluidized bed, a rotary drying method, an immersion drying method using a universal stirrer, or the like.

  In the resin-coated carrier, various resins are used as the resin used to coat the surface of the core material. Specific examples of the resin include fluorine resin, acrylic resin, epoxy resin, polyester resin, fluorine acrylic resin, acrylic / styrene resin, silicone resin, acrylic resin / polyester resin / epoxy resin / alkyd resin / urethane resin, etc. And modified silicone resins modified with (1) and cross-linked fluorine-modified silicone resins. Moreover, you may add a charge control agent, a resistance control agent, etc. to resin as needed.

  The above two-component developer is manufactured by mixing the toner and the carrier described above. The mixing ratio (mass ratio) of the toner and carrier in the developer is preferably in the range of toner: carrier = 1: 99 to 20:80, and preferably in the range of 3:97 to 12:88. More preferred.

<Process cartridge, image forming apparatus>
Hereinafter, the process cartridge and the image forming apparatus according to the present embodiment will be specifically described with reference to the drawings.

  FIG. 1 is a cross-sectional view schematically showing a basic configuration of an image forming apparatus according to a preferred embodiment. The image forming apparatus shown in FIG. 1 is a light fixing method, and uses a toner of four colors consisting of cyan, magenta, yellow and black.

  In FIG. 1, 1a to 1d are charging means, 2a to 2d are exposure means (electrostatic latent image forming means), 3a to 3d are photoreceptors (latent image holding bodies), 4a to 4d are developing means, and 41a to 41d are Developer holders 5a to 5d are cleaning means (toner removing means), 10 is a recording sheet (transferred body) fed in the direction of the arrow from the roll medium 15, 20 is a cyan developing unit, 30 is a magenta developing unit, and 40 is The yellow developing unit, 50 is a black developing unit, 70a to 70d are transfer means (transfer rolls), 71 and 72 are rolls, 80 is a transfer voltage supply means, and 90 is a light fixing means.

The image forming apparatus shown in FIG. 1 is disposed in contact with a recording sheet 10 and a developing unit for each color indicated by reference numerals 20, 30, 40, and 50 including a charging unit, an exposure unit, a photoconductor, and a developing unit. Rolls 71 and 72 for transporting the paper 10, transfer rolls 70a, 70b, 70c and 70d arranged so as to be in contact with the opposite side through the recording paper 10 so as to press the photoreceptor of each developing unit, Light for irradiating light on the side of the recording paper 10 that contacts the photoconductor of the recording paper 10 that passes through the pressure contact portion between the photoconductor and the transfer roll in the direction of the arrow in the figure. And fixing means 90.
In FIG. 1, not only the developing means 4a to 4d but also the developing units 20 to 50 can be the process cartridge. That is, if the process cartridge includes at least the developing holders 41a to 41d in the developing units 4a to 4d, the charging units 1a to 1d, the photoconductors 3a to 3d, the developing units 4a to 4d, and the cleaning units 5a to 5d. Any of these may or may not be included.

The cyan developing unit 20 has a configuration in which a charging unit 1a, an exposing unit 2a, a developing unit 4a, and a cleaning unit 5a are arranged clockwise around the photoreceptor 3a. Further, the transfer roll 70a is disposed opposite to the recording sheet 10 so as to be in contact with the surface of the photosensitive member 3a between the position of the developing unit 4a on the photosensitive member 3a and the position of the clockwise cleaning unit 5a.
Other color developing units follow this configuration. Further, in the developing units 1d to 4d, light fixing toners corresponding to the respective colors are stored.

Next, image formation using this image forming apparatus will be described.
First, in the cyan developing unit 20, the surface of the photoreceptor 3a is charged by the charging unit 1a while rotating the photoreceptor 3a in the clockwise direction. Next, the surface of the charged photoreceptor 3a is exposed by the exposure means 2a, so that a latent image corresponding to the cyan component image of the original image to be copied is formed on the surface of the photoreceptor 3a.

Further, the cyan toner stored in the developing means 4a is held on the developer holding body 41a of the developing means 4a and applied to the latent image on the surface of the photoreceptor 3a, whereby the latent image is developed and a cyan toner image. Is formed. At this time, the developer holder 41a rotates in the clockwise direction. Then, cyan toner or the like remaining on the photoreceptor 3a is removed by the cleaning unit 5a.
In the magenta developing unit 30, yellow developing unit 40, and black developing unit 50, a process similar to this is performed, and a toner image of each color is formed on the surface of the photosensitive member of the developing unit.

  The toner images of the respective colors formed on the surface of the photoreceptor are sequentially transferred onto the recording paper 10 conveyed in the direction of the arrow by the action of the transfer potential by the transfer rolls 70a to 70d, and recorded so as to correspond to the original image information. A full-color laminated toner image is formed by being laminated on the surface of the paper 10 in the order of cyan, magenta, yellow and black from the top layer.

Next, the laminated toner image on the recording paper 10 is conveyed to the light fixing means 90, where it is irradiated with light from the light fixing means 90, melted, and light-fixed on the recording paper 10 to form a full-color image. It is formed.
As described above, an image is formed.

The light fixing device used for light fixing may be a single light source that uses a light source (lamp) that emits near infrared light, such as an infrared lamp or a xenon lamp. There may be more than one. However, as a flash emission method, it is desirable to arrange a plurality of flash lamps, emit light a plurality of times with a delay of about 0.01 to 100 ms, and illuminate the same portion a plurality of times to achieve both void and fixability. This is called delay light emission.
The time (delay time) from the first light emission to the second light emission is preferably 0.1 to 50 ms. When flash irradiation is performed for a time shorter than 0.1 ms, voids may be generated, and when the time is 50 ms or more, the temperature of the printed material is lowered before the second light emission, and thus the light fixing effect may be small.

In addition, light energy (hereinafter sometimes referred to as “flash energy”) at the time of light fixing is transferred when four color light-fixed color toner images are stacked and light-fixed at one time (hereinafter, “ (Sometimes referred to as “four-color batch photofixing”), it is preferably within a range of about 2 to 7 J / cm ² .
If the flash energy is less than ² J / cm ² in the four-color batch light fixing, fixing may not be performed satisfactorily. On the other hand, if it exceeds 7 J / cm ² in the four-color batch light fixing, a void that is a printing defect of the toner, a burn of the recording medium, or the like may occur.

Here, the flash energy is represented by the following formula.
Formula: S = ((1/2) × C × V ² ) / (u × L) × (n × f)
In the above formula, n is the number of lamps that emit light at one time, f is the lighting frequency (Hz), V is the input voltage (V), C is the capacitor capacity (F), u is the process transport speed (cm / s) , L represents the effective light emission width of the lamp (usually maximum paper width, cm), and S represents flash energy (J / cm ² ).

  In the image forming apparatus shown in FIG. 1, the developer of the above embodiment is used as a developer, and the toner contained in the developer has the above configuration. Therefore, even if the process speed (the peripheral speed of the photoreceptor) is high. Further, chipping due to variations in the charge amount in the toner is suppressed.

  The process speed of the image forming apparatus is preferably 360 mm / s or more, more preferably 1000 mm / s or more, and further preferably 1500 mm / sec or more. In this embodiment, the developer of the above-described embodiment is used as the developer, and the toner contained in the developer has the above-described configuration. Therefore, even when the process speed is high, the tip due to the variation in the charge amount in the toner Chipping is suppressed.

  Further, in the image forming apparatus of the present embodiment, the movement direction of the surfaces of the photoreceptors 3a to 3d and the movement direction of the surfaces of the developer holding bodies 41a to 41d are opposite to each other at the position where the toner image is formed ( Counter method). The counter method has an advantage that it is easy to increase the process speed, but there is a case where the leading edge of the image is liable to occur. However, in this embodiment, the developer of the above-described embodiment is used as the developer, and the toner contained in the developer has the above-described configuration. Therefore, even in the counter method, the tip lack due to the variation in the charge amount of the toner is present. It is suppressed.

  FIG. 2 is a cross-sectional view schematically showing a basic configuration of an image forming apparatus according to another preferred embodiment. The image forming apparatus shown in FIG. 2 employs a heat roll fixing method.

2 includes an electrostatic latent image holding body 112, a charging unit 114, an electrostatic latent image forming unit 116, a developing unit 118, a transfer unit 120, a cleaning unit 122, a neutralizing unit 124, a fixing unit 126, A cartridge 128 is provided.
The developer stored in the developing unit 118 and the cartridge 128 is the developer of this embodiment.

  For convenience, FIG. 2 illustrates only a configuration including one developing unit 118 and one cartridge 128 each containing a developer according to the present embodiment. However, for example, in the case of a color image forming apparatus, the image forming apparatus includes A configuration including a corresponding number of developing means 118 and cartridges 128 may be employed.

  The image forming apparatus illustrated in FIG. 2 is an image forming apparatus having a configuration in which a cartridge 128 is detachably attached. The cartridge 128 is connected to the developing unit 118 through a developer supply pipe 130. Therefore, when image formation is performed, the developer of the above-described embodiment stored in the cartridge 128 is supplied to the developing unit 118 through the developer supply pipe 130, so that the development of the above-described embodiment is performed over a long period of time. An image using the agent is formed. Further, when the amount of developer stored in the cartridge 128 becomes small, the cartridge 128 may be replaced.

  Around the electrostatic latent image holding body 112, charging means 114 for charging the surface of the electrostatic latent image holding body 112 in order along the rotation direction (direction of arrow A) of the electrostatic latent image holding body 112, and image information. Accordingly, an electrostatic latent image forming means 116 for forming an electrostatic latent image on the surface of the electrostatic latent image holding body 112, a developing means 118 for supplying a developer to the formed electrostatic latent image, and an electrostatic latent image holding body 112. A drum-shaped transfer means 120 that contacts the surface and rotates following the direction of the arrow B as the electrostatic latent image holding body 112 rotates in the direction of arrow A, a cleaning means 122 that contacts the surface of the electrostatic latent image holding body 112, a static A neutralizing means 124 for neutralizing the surface of the electrostatic latent image holding body 112 is disposed.

  Between the electrostatic latent image holder 112 and the transfer unit 120, a recording medium 150 conveyed in the arrow C direction by a conveying unit (not shown) from the opposite side to the arrow C direction is inserted. A fixing unit 126 having a built-in heating source (not shown) is arranged on the electrostatic latent image holding body 112 in the direction of arrow C, and the fixing unit 126 is provided with a contact portion 132. The recording medium 150 that has passed between the electrostatic latent image holder 112 and the transfer unit 120 is inserted through the contact portion 132 in the direction of arrow C.

As the electrostatic latent image holding member 112, for example, a photosensitive member or a dielectric recording member is used.
As the photoreceptor, for example, a photoreceptor having a single layer structure or a photoreceptor having a multilayer structure is used. As the material of the photoconductor, an inorganic photoconductor such as selenium or amorphous silicon, an organic photoconductor, or the like can be considered.

  Examples of the charging means 114 include a contact charging device using a conductive or semiconductive roller, brush, film, rubber blade, etc., a non-contact charging device such as corotron charging or scorotron charging using corona discharge, etc. Well-known means are used.

As the electrostatic latent image forming unit 116, any conventionally known unit that forms a signal capable of forming a toner image at a desired position on the surface of the recording medium may be used in addition to the exposure unit.
As the exposure means, for example, a conventionally known exposure means such as a combination of a semiconductor laser and a scanning device, a laser scanning writing device constituted by an optical system, or an LED head may be used. In order to realize a desirable mode of producing a uniform and high-resolution exposure image, it is desirable to use a laser scanning writing device or an LED head.

  Specifically, as the transfer unit 120, for example, a conductive or semiconductive roller, brush, film, rubber blade, or the like to which a voltage is applied is used, and the electrostatic latent image holder 112 and the recording medium 150 are interposed. The charged toner is formed by corona charging the back surface of the recording medium 150 with a means for transferring a toner image formed of charged toner particles by using an electric field, a corotron charger using a corona discharge, or a scorotron charger. Conventionally known means such as a means for transferring a toner image formed with these particles may be used.

  Further, a secondary transfer unit may be used as the transfer unit 120. That is, although not shown, the secondary transfer unit is a unit that transfers the toner image to the intermediate transfer member and then secondary-transfers the toner image from the intermediate transfer member to the recording medium 150.

  Examples of the cleaning unit 122 include a cleaning blade and a cleaning brush. In the present embodiment, blade cleaning means using a cleaning blade is employed as the cleaning means 122.

  Examples of the static eliminating unit 124 include a tungsten lamp and an LED.

As the fixing unit 126, for example, a known contact-type heat fixing device is used.
Specifically, for example, a heating roll having a rubber elastic layer on the core metal and optionally having a surface layer of the fixing member, and a rubber elastic layer on the core metal, and if necessary, a fixing member A heat roll fixing device including a pressure roll provided with a surface layer, or a fixing device in which the combination of the roll and the roll is replaced with a combination of a roll and a belt or a combination of the belt and the belt.

  The recording medium 150 is not particularly limited, and conventionally known media such as plain paper and glossy paper are used. A recording medium having a base material and an image receiving layer formed on the base material may be used.

  Next, image formation using the image forming apparatus 110 will be described. First, as the electrostatic latent image holding body 112 rotates in the direction of arrow A, the surface of the electrostatic latent image holding body 112 is charged by the charging unit 114, and the electrostatic latent image holding body 112 is charged with the electrostatic latent image holding surface. The image forming unit 116 forms an electrostatic latent image corresponding to the image information. Then, a toner image is formed on the surface of the electrostatic latent image holding body 112 on which the electrostatic latent image is formed by supplying a developer from the developing unit 118 according to the color information of the electrostatic latent image.

  Next, the toner image formed on the surface of the electrostatic latent image holding body 112 is brought into contact with the electrostatic latent image holding body 112 and the transfer unit 120 as the electrostatic latent image holding body 112 rotates in the arrow A direction. Move to the department. At this time, the recording medium 150 is inserted through the contact portion in the direction of arrow C by a paper transport roll (not shown), and the electrostatic latent image is transferred by the voltage applied between the electrostatic latent image holder 112 and the transfer unit 120. The toner image formed on the surface of the image carrier 112 is transferred to the surface of the recording medium 150 at the contact portion.

  The toner remaining on the surface of the electrostatic latent image holding body 112 after the toner image is transferred by the transfer unit 120 is removed by the cleaning blade of the cleaning unit 122 and the charge is removed by the charge removing unit 124.

The recording medium 150 having the toner image transferred onto the surface in this way is conveyed to the contact portion 132 of the fixing unit 126 and, when passing through the contact portion 132, the recording medium 150 is contacted by a built-in heating source (not shown). The surface of the part 132 is heated by the heated fixing means 126. At this time, an image is formed by fixing the toner image on the surface of the recording medium 150.
As described above, an image is formed.

  In the image forming apparatus shown in FIG. 2, the developer of the above embodiment is used as the developer, and the toner contained in the developer has the above-described configuration, so that the leading edge chipping due to the variation in the charge amount of the toner is suppressed. Is done.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “parts” and “%” mean “parts by mass” and “% by mass” unless otherwise specified.

<Measurement method>
-Measuring method of glass transition temperature and melting point-
The glass transition temperature and melting point were measured based on JIS K7121-1987 using a differential scanning calorimeter (DSC-50 manufactured by Shimadzu Corporation). The melting point of a mixture of indium and zinc was used for temperature correction of the detection part of this apparatus, and the heat of fusion of indium was used for correction of heat quantity. The sample was put in an aluminum pan, an aluminum pan containing the sample and an empty aluminum pan for control were set, and the measurement was performed at a heating rate of 10 ° C./min.
About melting | fusing point, it was set as melting | fusing point with the temperature of the peak of the largest endothermic peak among the endothermic peaks of the DSC curve obtained by measurement.
Moreover, about the glass transition temperature, it was set as the glass transition point with the temperature of the intersection of the extended line of the base line in the endothermic part of the DSC curve obtained by the measurement, and the rising line.

-Measurement method of volume average particle diameter of toner-
The volume average particle diameter of the toner was measured using a Coulter Multisizer II type (manufactured by Beckman Coulter, Inc.) with an aperture diameter of 100 μm. At this time, the measurement is performed after the toner is dispersed in an electrolyte aqueous solution (Isoton aqueous solution, manufactured by Beckman Coulter, Inc.) and dispersed by ultrasonic waves for 30 seconds or more.

  As a measuring method, 0.5 to 50 mg of a measurement sample is added to 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate as a dispersant, and this is added to 100 to 150 ml of the electrolytic solution. The electrolytic solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of the particles is measured. The number of particles to be measured is 50,000.

  For the measured particle size distribution, a cumulative distribution is drawn from the smaller diameter side with respect to the divided particle size range (channel), and the particle size at which 50% is accumulated is defined as the volume average particle size.

―Method for measuring weight average molecular weight―
The weight average molecular weight can be measured under the following conditions. GPC uses “HLC-8120GPC, SC-8020 (manufactured by Tosoh Corporation)”, and the column uses two “TSKgel, SuperHM-H (6.0 mm ID × 15 cm, manufactured by Tosoh Corporation)” THF (tetrahydrofuran) was used as an eluent. As experimental conditions, the sample concentration was 0.5%, and the flow rate was 0.6 ml / min. The experiment was conducted using an IR detector with a sample injection amount of 10 μL and a measurement temperature of 40 ° C. The calibration curve is “polystylen standard sample TSK standard” manufactured by Tosoh Corporation: “A-500”, “F-1”, “F-10”, “F-80”, “F-380”, “A-2500”. ”,“ F-4 ”,“ F-40 ”,“ F-128 ”, and“ F-700 ”.

<Example A>
[Production of Graft Polymer 1]
To 80 parts of a styrene-acrylonitrile-butyl acrylate copolymer (Tg = 59 ° C., weight average molecular weight: 9000, monomer ratio: 70% by mass of styrene, 7% by mass of acrylonitrile, 23% by mass of butyl acrylate), polyethylene wax ( Made by Clariant: Trade name PE520, weight average molecular weight: 520, melting point: 90 ° C. 10 parts and polypropylene wax (Mitsui Chemicals trade name: NP105) 10 parts are graft-polymerized as follows, and graft polymer 1 Was made.
Specifically, 1 part of 2,2′-azobisisobutyronitrile is added to the styrene-acrylonitrile-butyl acrylate copolymer, then the polyethylene wax and the polypropylene wax are added, and the mixture is added at 180 ° C. for 60 minutes. The graft polymer 1 was obtained by mixing.
Graft polymer 1 had a glass transition temperature of 59 ° C. and a weight average molecular weight of 13,000.

[Preparation of Toner Resin Composition A1]
Graft polymer 1: 9.0 parts by weight Polyester resin (trade name: FP118, manufactured by Kao): 72.0 parts by weight Paraffin wax (trade name: Cerisust 2051-2, manufactured by Clariant Japan, melting point: 110 ° C.): 3.0 parts by mass / polyethylene wax (trade name: PE1101, manufactured by Clariant Japan, weight average molecular weight: 12000): 4.0 parts by mass / colorant (CI Pigment Yellow 180, trade name: Toner Yellow HG, (Manufactured by Clariant Japan): 8.0 parts by mass / charge control agent (quaternary ammonium salt, trade name: TP415 Hodogaya Chemical): 0.5 parts by mass / charge control agent (quaternary ammonium salt, trade name: P51, Orient Chemical Co., Ltd.): 0.5 parts by mass, infrared absorber (aluminum salt compound, trade name: IRG -002, manufactured by Nippon Kayaku Co., Ltd.): 1.0 part by mass

  The above materials were powder-mixed with a Henschel mixer, heat-kneaded with an extruder having a set temperature of 105 ° C., and cooled to obtain a toner resin composition A1. The wax dispersion value in the composition of the toner resin composition A1 was measured by the above method and found to be 0.01%.

[Production of Toner Resin Composition A7 from Toner Resin Composition A2]
Toner resin composition A7 was prepared from toner resin composition A2 in the same manner as toner resin composition A1 except that the amounts of graft polymer 1 and polyester resin added were as shown in Table 1. Table 1 shows the wax dispersion values in the resin composition for toner.

[Preparation of Toner A1]
The toner resin composition A1 produced above was coarsely pulverized with a jet mill, pulverized with a kryptron, and then classified with air classification to obtain toner particles having a volume average particle diameter of 6.0 μm.
Toner A1 was obtained by mixing 100 parts of the toner particles and 1.0 part of hydrophobic silica particles (trade name RA200H, manufactured by Nippon Aerosil Co., Ltd.) with a Henschel mixer. The wax dispersion value in the toner of the toner A1 was measured by the above method and found to be 0.03%.

[Preparation of Toner A2 to Toner A7]
Toner A7 was produced from toner A2 in the same manner as toner A1, except that toner resin composition A2 to toner resin composition A7 were used instead of toner resin composition A1. The wax dispersion values in the toners of the toner A2 to the toner A7 were measured by the above-described method, and were found to be 1.2%, 2.3%, 4.3%, 5.7%, 7.5%, 10.5%, respectively. Met.

[Adjustment of developer]
The toner prepared in the above (toner A1 to toner A7) and a ferrite carrier having a volume average particle diameter of 60 μm (coated with polymethyl methacrylate having a weight average molecular weight of 80000 on the surface by 1.0% by weight) The developer was adjusted by mixing so that the concentration was 4.5% by mass.

[Evaluation of chipping at the tip]
Using the developer described above and plain paper (NPI-1500LT, Kobayashi recording paper, 64 g / m ² ) as a recording medium, a 1-inch square solid image (toner on the recording medium) is formed by a light fixing type image forming apparatus. Adhering amount: 0.6 mg / cm ² , a fixed image of 2.54 × 2.54 cm ² ) was formed. Image formation was performed under the conditions of a process speed of 1200 m / s and a counter method (a method in which the rotation direction of the photosensitive member and the rotation direction of the developer holding member are opposite directions) in an environment of a temperature of 20 ° C. and a humidity of 50%. The degree of blurring at the tip portion (boundary region between the image portion and the non-image portion) of the formed image was visually observed. The evaluation criteria for chipping at the tip are as follows, and the evaluation results are shown in Table 1.

-Evaluation standard for chipping at the tip-
A: No fading is observed at all. B: A slight faint is observed, but it is not a problem.
C: Slight faintness is observed, but is practically acceptable.
D: Fading is remarkable, image abnormality is recognized, and this is a level that causes a problem in practical use.
The evaluation was performed for every 10000 sheets up to 30000 sheets, and the evaluation was stopped when D was reached. As for the notation, evaluations for every 10,000, 20000 and 30000 sheets are arranged from the left. For example, if 10000 sheets are A, 20000 sheets are A, and 30000 sheets are B, then it is AAB. In addition, for those finished at the stage of becoming D, for example, 10000 copies were indicated as C, and 20000 copies as D were not implemented, and 30000 copies were indicated as CD.
The allowable range is 30000 sheets and C.

The image forming apparatus used is a modified machine (FIG. 1) of a printer (product of Fuji Xerox) having a product number CF1100 equipped with a xenon flash lamp having a high emission intensity in a wavelength range of 700 to 1500 nm as an optical fixing device. .
In addition, the xenon flash lamp emits light by a delay emission method in which light emission per unit area is performed twice. The total energy for flash fixing was 3.0 J / cm ² and the delay time was 0.5 ms (milliseconds).

<Example B>
[Preparation of Toner Resin Composition B8 from Toner Resin Composition B1]
A toner resin composition B8 was prepared from the toner resin composition B1 in the same manner as the toner resin composition A1 except that the types of paraffin wax were as shown in Table 2. The toner resin composition B5 uses the same type of paraffin wax as the toner resin composition A1. The wax dispersion values in the compositions of the toner resin composition B1 to the toner resin composition B8 were all 0.01%. Table 2 shows the melting point of the paraffin wax used.

[Preparation of Toner B1 to Toner B8]
Toner B1 to toner B8 were prepared in the same manner as toner A1, except that toner resin composition B1 to toner resin composition B8 were used instead of toner resin composition A1. When the wax dispersion values in toner B1 to toner B8 were measured by the above method, they were 0.07%, 0.05%, 0.05%, 0.04%, 0.03%, and 0.03%, respectively. 0.04% and 0.06%.

[Adjustment of developer]
The toner prepared in the above (toner B1 to toner B8) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.

[Evaluation of chipping at the tip]
In the same manner as in Example A, the tip chipping was evaluated. The evaluation results are shown in Table 2.

[Evaluation of fixability]
The image used for evaluation of chipping at the tip was used to evaluate the fixability.

Specifically, the fixing rate of the obtained image was evaluated as follows. First, the status A density (OD1) corresponding to each color of the image is measured, and then an adhesive tape (Scotch Mending Tape, manufactured by Sumitomo 3M) is applied on the image, and then the adhesive tape is peeled off. The status A density (OD2) of the image was measured. In addition, (X-rite 938) was used for the measurement of optical density. Next, the fixing ratio was calculated from the following equation using the obtained optical density value.
Formula: Fixing rate (%) = OD2 / OD1 × 100

Fixability evaluation criteria are as follows, and the evaluation results are shown in Table 2.
-Evaluation criteria for fixability-
A: The fixing rate is 99% or more.
B: The fixing rate is 80% or more and less than 90%.
C: The fixing rate is 70% or more and less than 80%.
D: Fixing rate is less than 70%.
The fixing property is also evaluated every 10,000 sheets, and the notation method and tolerance are the same as the evaluation level of the tip missing, and the tolerance is 30,000 sheets or more and C or more.

  The image forming apparatus used is the same apparatus as the image forming apparatus used for the evaluation of chipping at the tip.

<Example C>
[Preparation of Toner Resin Composition C8 from Toner Resin Composition C1]
A toner resin composition C8 was produced from the toner resin composition C1 in the same manner as in the toner resin composition A4 except that the types of paraffin wax were as shown in Table 3. The toner resin composition C5 uses the same type of paraffin wax as the toner resin composition A4. The wax dispersion values in the compositions of the toner resin composition C1 to the toner resin composition C8 were all 4.0%. Table 3 shows the melting point of the paraffin wax used.

[Preparation of Toner C1 to Toner C8]
Toner C1 to toner C8 were produced in the same manner as toner A4, except that toner resin composition C1 to toner resin composition C8 were used instead of toner resin composition A4. When the wax dispersion values in toner C1 to toner C8 were measured by the above method, they were 4.8%, 4.6%, 4.5%, 4.3%, 4.3%, and 4.4%, respectively. It was 4.3% and 4.2%.

[Adjustment of developer]
The toner prepared in the above (toner C1 to toner C8) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.

[Evaluation of chipping and fixing properties]
In the same manner as in Example B, evaluation of chipping at the tip and evaluation of fixability were performed. The evaluation results are shown in Table 3.

<Example D>
[Preparation of Toner Resin Composition D1 from Toner Resin Composition D1]
A toner resin composition D5 was produced from the toner resin composition D1 in the same manner as the toner resin composition A1 except that the types of polyethylene wax were as shown in Table 4. The toner resin composition D4 uses the same type of polyethylene wax as the toner resin composition A1. The wax dispersion values in the compositions of the toner resin composition D1 to the toner resin composition D5 were both 0.01%. Table 4 shows the weight average molecular weight of the polyethylene wax used.

[Production of Toner D1 to Toner D5]
Toner D1 to toner D5 were produced in the same manner as toner A1, except that toner resin composition D1 to toner resin composition D5 were used instead of toner resin composition A1. When the wax dispersion values in the toners D1 to D5 were measured by the above method, they were 0.1%, 0.05%, 0.03%, 0.03%, and 0.05%, respectively.

[Adjustment of developer]
The toner prepared in the above (toner D1 to toner D5) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.

[Evaluation of chipping and fixing properties]
In the same manner as in Example B, evaluation of chipping at the tip and evaluation of fixability were performed. The evaluation results are shown in Table 4.

<Example E>
[Preparation of Toner Resin Composition E5 from Toner Resin Composition E1]
A toner resin composition E5 was produced from the toner resin composition E1 in the same manner as in the toner resin composition A4 except that the types of polyethylene wax were as shown in Table 5. The toner resin composition E4 uses the same type of polyethylene wax as the toner resin composition A4. The wax dispersion values in the compositions of the toner resin composition E1 to the toner resin composition E5 were all 4.0%. Table 5 shows the weight average molecular weight of the polyethylene wax used.

[Preparation of Toner E1 to Toner E5]
Toner E1 to toner E5 were produced in the same manner as toner A4, except that toner resin composition E1 to toner resin composition E5 were used instead of toner resin composition A4. The wax dispersion values in the toners from the toner E1 to the toner E5 were measured by the above method, and were found to be 4.8%, 4.5%, 4.4%, 4.3%, and 4.2%, respectively.

[Adjustment of developer]
The toner prepared in the above (toner E1 to toner E5) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.

[Evaluation of chipping and fixing properties]
In the same manner as in Example B, evaluation of chipping at the tip and evaluation of fixability were performed. The evaluation results are shown in Table 5.

<Example F>
[Evaluation of chipping at the tip]
The developer produced in the same manner as in Example A using the toner A1 produced above was used, the process speed was changed from 50 mm / s to 2000 mm / s, and the counter method (the rotation direction of the photosensitive member and the developer holding member) was changed. Image formation was performed by a method in which the rotation direction is the reverse direction) and a width method (method in which the rotation direction of the photosensitive member and the rotation direction of the developer holding member are the same direction). The degree of blurring at the tip portion (boundary region between the image portion and the non-image portion) of the formed image was visually observed, and tip failure was evaluated according to the same evaluation criteria as in Example A. Table 6 shows the process speed, method (counter method or with method), and evaluation results.

<Reference Example G>
[Evaluation of chipping at the tip]
Using the toner A5 produced above, the chipping of the tip was evaluated in the same manner as in Example F. Table 7 shows the process speed, method (counter method or with method), and evaluation results.

<Example H> (Thermal fixing method)
[Preparation of Toner Resin Composition H7 from Toner Resin Composition H1]
A toner resin composition H7 was prepared from the toner resin composition H1 in the same manner as the toner resin composition A1 to the toner resin composition A7, except that no infrared absorber was contained. Table 8 shows the wax dispersion value in the resin composition for toner.

[Production of Toner H1 to Toner H7]
Toner H1 to toner H7 were prepared in the same manner as toner A1, except that toner resin composition H1 to toner resin composition H7 were used instead of toner resin composition A1. When the wax dispersion values in the toners of the toner H1 to the toner H7 were measured by the above method, they were 0.03%, 1.2%, 2.3%, 4.3%, 5.7%, and 7.5%, respectively. 10.5%.

[Adjustment of developer]
The toner prepared in the above (toner H1 to toner H7) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.
[Evaluation of chipping at the tip]
Using the developer produced above and plain paper (NPI-1500LT, Kobayashi recording paper, 64 g / m ² ) as the recording medium, the leading edge portion of the formed image (boundary area between the image portion and the non-image portion) The degree of faintness was visually observed. The evaluation criteria for the chipping at the tip are the same as in Example A, and the evaluation results are shown in Table 8.

  The image forming apparatus used in Example H is a modified machine in which the optical fixing device of the image forming apparatus used in Example A is replaced with a heat roll fixing device, and the fixing temperature is set to 180 ° C.

<Example J>
[Production of Graft Polymer 2]
Instead of 100 parts of styrene-acrylonitrile-butyl acrylate copolymer (Tg = 51 ° C., weight average molecular weight: 9000, monomer ratio: 65% by mass of styrene, 6% by mass of acrylonitrile, 29% by mass of butyl acrylate) A graft polymer 2 was prepared in the same manner as the graft polymer 1 except for the above.
Graft polymer 2 had a glass transition temperature of 52 ° C. and a weight average molecular weight of 12,000.

[Production of Toner Resin Composition J1 to Toner Resin Composition J7]
From the toner resin composition J1 to the toner in the same manner as in the toner resin composition A1, except that the graft polymer 2 was used instead of the graft polymer 1 and the amount of the graft polymer 2 added was as shown in Table 9. Resin composition J7 was prepared. Table 9 shows the wax dispersion values in the resin composition for toner.

[Preparation of Toner J1 to Toner J7]
Toner J1 to toner J7 were prepared in the same manner as toner A1, except that toner resin composition J1 to toner resin composition J7 were used instead of toner resin composition A1. When the wax dispersion values in toner J1 to toner J7 were measured by the above method, they were 0.03%, 1.4%, 2.5%, 4.4%, 5.8%, and 7.7%, respectively. 11.0%.
[Adjustment of developer]
The toner prepared in the above (toner J1 to toner J7) and a ferrite carrier having a volume average particle diameter of 60 μm were mixed so as to have a toner concentration of 4.5% by mass to prepare a developer.

[Evaluation of chipping at the tip]
In the same manner as in Example A, the tip chipping was evaluated. Table 9 shows the evaluation results.

  From the results shown in Tables 1 to 9, it can be seen that in the example, the leading edge defect of the image due to the variation in the charge amount of the toner is suppressed as compared with the comparative example.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment.

Explanation of symbols

1a, 1b, 1c, 1d Charging means 2a, 2b, 2c, 2d Exposure means (electrostatic latent image forming means)
3a, 3b, 3c, 3d photoconductor (latent image carrier)
4a, 4b, 4c, 4d Developing means 41a, 41b, 41c, 41d Developer holders 5a, 5b, 5c, 5d Cleaning means 10 Recording paper (transferred material)
70a, 70b, 70c, 70d Transfer roll (transfer means)
90 Light fixing means (fixing means)
DESCRIPTION OF SYMBOLS 110 Image forming apparatus 112 Electrostatic latent image holding body 114 Charging means 116 Electrostatic latent image forming means 118 Developing means 120 Transfer means 126 Fixing means 128 Cartridge 150 Recording medium

Claims (16)

A binder resin containing a vinyl-based resin grafted with polyolefin, and a release agent containing paraffin wax,
A toner resin composition for developing an electrostatic charge image, wherein a dispersion value of the release agent in the toner resin composition is 4% or less.   The resin composition for toner for developing electrostatic images according to claim 1, further comprising an infrared absorber.   The resin composition for toner for developing an electrostatic charge image according to claim 1, wherein the paraffin wax has a melting point of 95 ° C. or higher and 114 ° C. or lower.   4. The resin composition for a toner for developing an electrostatic charge image according to claim 1, wherein the release agent contains a polyethylene wax having a weight average molecular weight of 8000 or more and 23000 or less.   A colorant, wherein the colorant is C.I. I. The resin composition for toner for developing electrostatic images according to claim 1, which is CI Pigment Yellow 180.   An electrostatic image developing toner obtained by pulverizing the resin composition for electrostatic image developing toner according to any one of claims 1 to 5. A binder resin containing a vinyl-based resin grafted with polyolefin, and a release agent containing paraffin wax,
A toner for developing an electrostatic charge image, wherein a dispersion value of the releasing agent in the toner is 5% or less.   The toner for developing an electrostatic charge image according to claim 7, further comprising an infrared absorber.   The electrostatic image developing toner according to claim 7, wherein the paraffin wax has a melting point of 95 ° C. or higher and 114 ° C. or lower.   10. The electrostatic image developing toner according to claim 7, wherein the release agent contains a polyethylene wax having a weight average molecular weight of 8000 to 23000. 11.   A colorant, wherein the colorant is C.I. I. The toner for developing an electrostatic charge image according to any one of claims 7 to 10, which is CI Pigment Yellow 180.   An electrostatic image developing developer comprising at least the electrostatic image developing toner according to any one of claims 6 to 11.   A process cartridge comprising a developer holder and containing the developer for developing an electrostatic image according to claim 12. A latent image carrier,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the latent image holding member;
Developing means for developing the electrostatic latent image with a developer containing toner to form a toner image;
Transfer means for transferring the toner image formed on the latent image holding member onto a transfer target;
Fixing means for fixing the toner image transferred onto the transfer target member to the transfer target member,
The image forming apparatus according to claim 12, wherein the developer is an electrostatic charge image developing developer.   The image forming apparatus according to claim 14, wherein the process speed is 360 mm / s or more. The developing means includes a developer holder;
The image forming apparatus according to claim 14, wherein a movement direction of the surface of the latent image holding member and a movement direction of the surface of the developer holding member at a position where the toner image is formed are opposite to each other.

Images