JP2008176205A - Toner for optical fixing, electrostatic charge image developer, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner for optical fixing having excellent safety and improving fixability in an optical fixing process. <P>SOLUTION: The toner for optical fixing comprises: a binder resin; a coloring agent; and a compound expressed by structural formula (1). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner for photofixing, an electrostatic charge image developer, a process cartridge, an image forming apparatus, and an image forming apparatus.

  In the electrophotographic system widely used in copying machines, printers, printing machines, etc., image formation is generally performed as follows. First, after a charging step for giving a positive or negative uniform electrostatic charge to the photoconductive insulator surface of the photosensitive drum, the surface of the insulator is irradiated with, for example, laser light (or LED) on the photoconductive insulator surface. The electrostatic charge is partially erased to form an electrostatic latent image corresponding to the image information. Next, for example, a fine powder of a developer called toner is attached to the latent image portion on which the electrostatic charge remains on the photoconductive insulator, and the latent image is visualized as a toner image. In order to make the toner image thus obtained into a printed matter, generally, the toner image is electrostatically transferred to a recording medium such as recording paper, and then the toner image is fixed to the recording medium.

  For fixing the toner image after the transfer, a method of solidifying and fixing after melting the toner by pressure, heating, or a method using a combination thereof, or a method of solidifying and fixing after melting the toner by irradiating light energy Although there is a method of using both paper heating and light energy irradiation in combination, a light fixing method using light mainly attracts attention. As the light fixing method, a flash fixing method using a xenon flash lamp and a laser fixing method using a high-intensity laser are known.

  That is, in the photofixing method, since it is not necessary to pressurize the toner when fixing the toner, it is not necessary to make contact (pressurization) with a fixing roller or the like, and there is little deterioration in image resolution (reproducibility) in the fixing process. There are advantages. In addition, since there is no need to heat with a heat source, printing does not occur until the heat source (fixing roller, etc.) is preheated to the desired temperature after the power is turned on. Yes. In addition, since a high-temperature heat source is not required, there is an advantage that the temperature rise in the apparatus can be appropriately avoided, and even when a recording paper jam occurs in the fixing device due to a system down, The recording paper is not altered or ignited by heat.

As for the above-mentioned photofixing method, as in the case of general heat roll toners, improvement of fixability has been promoted by controlling binder (binder resin) design, wax design, and wax dispersion state. Many proposals have been made to improve fixability in light fixing (for example, see Patent Documents 1 to 5).
In addition, it is known that perchlorate is used for the toner, and the fixing property is improved by causing the perchlorate substance to decompose and generate heat by increasing the temperature by fixing light. For example, see Patent Document 6).
JP-A-9-104741 JP 2003-149852 A JP 2003-186236 A JP 2003-270842 A JP 2002-156775 A JP 61-132959 A

  An object of the present invention is to provide a toner for photofixing that is excellent in safety and improves fixability in a photofixing method, an electrostatic charge image developer using the toner, a process cartridge, and an image forming apparatus.

The above-mentioned subject is achieved by the following present invention.
That is, the invention according to claim 1 is a toner for photofixing comprising a binder resin, a colorant and a compound represented by the following structural formula (1).

In the above formula, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted cyclohexane having 5 to 7 carbon atoms. Represents an alkyl group. In addition, as a substituent, it is either a benzyl group or a phenyl group which may have a chlorine atom, a bromine atom, and a C1-C4 alkyl group each independently.

  The invention according to claim 2 is a photofixing toner in which the compound represented by the structural formula (1) according to claim 1 is the following compound (1).

  The invention according to claim 3 is the photofixing toner in which the content of the compound in the photofixing toner according to claim 1 or 2 is in the range of 0.5 to 20% by mass in the whole toner.

  The invention according to claim 4 is the toner for light fixing according to any one of claims 1 to 3, which has an exothermic peak in a range of 200 to 350 ° C. in differential scanning calorimetry.

  The invention according to claim 5 is the photofixing toner according to any one of claims 1 to 4, wherein the calorific value obtained from the exothermic peak is in the range of 1 to 35 mJ / mg.

  A sixth aspect of the present invention is the photofixing toner according to any one of the first to fifth aspects, wherein the colorant includes carbon black.

  The invention according to claim 7 is the toner for photofixing according to any one of claims 1 to 6, which is a positively chargeable toner.

  The invention according to claim 8 is an electrostatic charge image developer comprising toner, wherein the toner is the photofixing toner according to any one of claims 1 to 7.

  The invention according to claim 9 is a process cartridge including at least a developer holder and containing the electrostatic charge image developer according to claim 8.

The invention according to claim 10 has toner image forming means for forming a toner image on a recording medium with a developer containing toner, and fixing means for fixing the toner image on the recording medium with light,
The image forming apparatus according to claim 8, wherein the developer is an electrostatic charge image developer.

According to the first aspect of the present invention, by adding the compound represented by the structural formula (1), a toner for photofixing that is excellent in safety and improves the fixability in the photofixing method can be obtained. Can do.
According to the second aspect of the present invention, by adding the compound represented by the compound (1), it is possible to obtain a photofixing toner that is more safe and improves the fixability in the photofixing method.
According to the invention of claim 3, by adding an appropriate amount of the compound represented by the structural formula (1), a toner having sufficient fixability to flash light can be obtained.
According to the invention of claim 4, by controlling the temperature range having the exothermic peak of the compound represented by the structural formula (1), there is no fear of heat generation during the production and storage of the toner, and the flash is stable. A toner that melts efficiently with respect to light can be obtained.
According to the fifth aspect of the invention, by controlling the amount of heat generated by the compound represented by the structural formula (1), it is possible to obtain a toner that melts more efficiently with respect to flash light.
According to the sixth aspect of the present invention, a high fixing rate with respect to flash light can be obtained particularly when black toner is used.
According to the seventh aspect of the invention, it is possible to obtain a toner for light fixing that is desirable for a high-speed machine.
According to the invention of claim 8, by using a developer containing a toner to which the compound represented by the structural formula (1) is added, a toner image having excellent safety and good fixability in the photofixing method can be obtained. Can be formed.
According to the ninth aspect of the present invention, it is possible to easily handle an electrostatic charge image developer that is excellent in safety and can improve the fixability in the photofixing method as compared with the case where this configuration is not provided. Therefore, adaptability to image forming apparatuses having various configurations can be enhanced.
According to the tenth aspect of the present invention, it is possible to maintain image formation having sufficient fixability with respect to flash light as compared with the case where this configuration is not provided.

Hereinafter, the present invention will be described in detail.
<Toner for light fixing>
The photofixing toner of the present invention (hereinafter sometimes simply referred to as “toner”) includes a binder resin, a colorant, and a compound represented by the following structural formula (1).

In the above formula, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted cyclohexane having 5 to 7 carbon atoms. Represents an alkyl group. In addition, as a substituent, it is either a benzyl group or a phenyl group which may have a chlorine atom, a bromine atom, and a C1-C4 alkyl group each independently.

A xenon lamp is preferably used as a flash lamp in the flash fixing method, which is one of the above-described photofixing methods, but the emission spectrum of the xenon lamp has no emission peak in the visible region, and extends from the near infrared region of 830 nm to 1000 nm. An intermittent emission line spectrum is shown.
On the other hand, as the toner to be irradiated with light, basically only the colorant absorbs light, so except for black toner, there is almost no absorption in the near-infrared region, and sufficient fixing with flash light cannot be performed. . Further, even in the case of black toner, it is difficult to say that the toner has sufficient fixability in consideration of speeding up and reduction of the light quantity of the flash lamp.

  For the above reasons, the present inventors examined a material that generates heat by light absorption as a fixing aid. However, when the toner is produced by a melt-kneading method, for example, if a normal photoinitiated polymerization agent is used as a heat generating material, there is a risk of explosion during the production, and if the addition amount in the toner is increased, toner ignition, etc. There was a problem in terms of safety.

On the other hand, according to the temperature simulation of black toner, the surface temperature of the toner exceeds 500 ° C. by flash light, although it is instantaneous for 1 ms or less. Therefore, if this temperature can be used effectively and heat can be generated in the fixing aid, the fixability can be improved.
That is, by adding a material that reacts exothermically at a temperature higher than the toner kneading temperature (usually about 100 to 200 ° C.) and lower than the temperature reached on the toner surface (about 500 ° C.) in flash fixing to the toner as a fixing aid, Both safety and high fixability can be achieved.

  From the above viewpoint, as a result of intensive studies by the present inventors, by using the compound represented by the structural formula (1) for the toner for photofixing, it is stable from the toner production process to the storage after the production, It was found that high photofixability can be obtained.

The compound represented by the structural formula (1) is not particularly limited as long as it is excellent in dispersibility with respect to the binder resin and the like and does not adversely affect the toner characteristics, but is a material that starts to generate heat by decomposition at 200 to 350 ° C. A material that starts decomposition and heat generation at 250 to 250 ° C. is more desirable. Further, it is desirable that the by-product that adversely affects the color tone and charging characteristics of the toner is not generated by the above decomposition.
The decomposition and exothermic starting temperatures of the above compounds can be confirmed as the starting point of the exothermic peak (rising point from the baseline) in differential scanning calorimetry described later.

Specifically, in the structural formula (1), R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, but R ¹ and R ² are alkyl groups having 1 to 4 carbon atoms. And is more preferably a methyl group.
In the structural formula (1), R ³ represents an alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted cycloalkyl group having 5 to 7 carbon atoms, and is an alkyl group having 1 to 4 carbon atoms. It is desirable that it is a methyl group.

The compound represented by the structural formula (1) is mixed with a binder resin, which will be described later, and contained in the toner. The content of the whole toner is preferably in the range of 0.5 to 20% by mass. More preferably, it is in the range of 1.0 to 5.0% by mass.
If the content is less than 0.5% by mass, a sufficient fixing effect may not be obtained. In addition, as described later, since the compound has a positive chargeability, it is desirable to use it as a positively chargeable toner. However, if the content is more than 20% by mass, the charge amount on the positive charge side is increased by continuous printing. In some cases, the print density may be too thin.

The toner containing the compound represented by the structural formula (1) as described above preferably has an exothermic peak in the range of 200 to 350 ° C. in the range of 250 to 350 ° C. in the differential scanning calorimetry (DSC). It is more desirable to have an exothermic peak. By having an exothermic peak in this temperature range, there is no fear of heat generation during production and storage, and the toner is stable and can be efficiently melted against flash light.
The exothermic peak refers to a peak of 0.5 mJ or more protruding toward the exothermic side with respect to the base line in the DSC curve under the measurement conditions described later, and the temperature of the exothermic peak refers to the peak apex temperature.

The calorific value obtained from the exothermic peak is preferably in the range of 1 to 35 mJ / mg, and more preferably in the range of 1 to 15 mJ / mg. If the calorific value is less than 1 mJ / mg, the fixability to flash light may not be improved. When it exceeds 35 mJ / mg, not only toner scattering but also toner sublimation starts at the time of fixing, and on the contrary, fixability may appear to deteriorate.
The calorific value is obtained by calculating the peak area of the exothermic peak from the DSC curve under the measurement conditions described later by a method according to JIS K7122, and calculating the transition heat from the peak area.

  The above differential scanning calorimetry is performed by setting the object to be measured on a differential scanning calorimeter (DSC-50, manufactured by Shimadzu Corp.) equipped with an automatic tangential processing system, and heating from room temperature to 500 ° C at a heating rate of 10 ° C / min. And each temperature and the emitted-heat amount were calculated | required by the said method from the obtained DSC curve. The same applies to the following.

Hereinafter, the details of the toner for photofixing of the present invention will be described together with its production method according to the embodiment.
(Binder resin)
As the binder resin in this embodiment, a known binder resin can be used. The main component of the binder resin is preferably polyester or polyolefin, but a copolymer of styrene and acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, etc., polyvinyl chloride, phenol resin, acrylic resin, methacrylic resin , Polyvinyl acetate, silicone resin, polyester resin, polyurethane, polyamide resin, furan resin, epoxy resin, xylene resin, polyvinyl butyral, terpene resin, coumarone indene resin, petroleum resin, polyether polyol resin, etc. alone or in combination can do. From the viewpoints of durability and translucency, it is preferable to use a polyester resin or a norbornene polyolefin resin.

The polyester resin preferably used in these will be further described. The acid component used in the polyester resin includes, for example, terephthalic acid, isophthalic acid, orthophthalic acid, or an anhydride thereof, and preferably terephthalic acid / Isophthalic acid. Examples of other acid components include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid and the like. These acid components may be used alone or in combination of two or more. The acid component may be a constituent component in the resin, and a polymerizable monomer used in the transesterification reaction, more specifically, methyl ester, ethyl ester, or the like of the acid component can be used.
Furthermore, in order to crosslink the polyester resin, a trivalent or higher carboxylic acid component can also be mixed and used as another acid component. Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, other polycarboxylic acids, and anhydrides thereof.

Examples of the alcohol component in the polyester resin used as the binder resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and neopentyl. Examples thereof include diols such as glycol, 1,4-butenediol, 1,5-pentanediol, and 1,6-hexanediol, and other dihydric alcohols such as bisphenol A and hydrogenated bisphenol A.
The Tg (glass transition point) of the binder resin used for the toner described above is preferably in the range of 50 to 70 ° C.

(Coloring agent)
As the colorant, those shown below can be appropriately selected and used according to the color of the toner.
For example, in cyan toner, as the colorant, for example, 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 products of phthalocyanine blue, fast sky blue, indanthrene blue BC cyan pigment, C.I. I. Cyan dyes such as solvent cyan 79 and 162 can be used. Among these, C.I. I. Pigment Blue 15: 3 is effective.

  In the magenta toner, as the colorant, for example, C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 21, 22, 23, 30, 31, 32, 37, 38, 39, 40, 41, 48, 49, 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, 209, etc., magenta pigments of Pigment Violet 19, 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 can be used.

In the case of yellow toner, examples of the colorant include C.I. I. Yellow pigments such as CI Pigment Yellow 2, 3, 3, 15, 16, 17, 97, 180, 185, and 139 can be used.
Further, the toner may be manufactured using various general-purpose colorants such as general-purpose red, blue, green, orange, purple, brown, and white.

As described above, since the surface temperature rises most when black toner is used in flash fixing, the heat generation mechanism using the compound represented by the structural formula (1) in the present invention can be used effectively. Therefore, the compound is preferably used for black toner.
Examples of the colorant that can be used for the black toner include carbon black, activated carbon, titanium black, magnetic powder, Mn-containing nonmagnetic powder, and the like. Is most desirable.

  The amount of each colorant added is preferably in the range of 2 to 15 parts by mass in 100 parts by mass of final toner particles prepared by mixing with a binder resin or the like. Furthermore, Preferably, it is the range of 3-7 mass parts. When the amount is less than 2 parts by mass, the coloring power of the toner may be reduced. If it is more than 15 parts by mass, it may be unusable due to the influence of chargeability.

(Other ingredients)
In addition to the compound represented by the structural formula (1), generally known infrared absorbers can be used in combination with the photofixing toner of this embodiment as a fixing aid. Here, the infrared absorber refers to a material having at least one strong light absorption peak in the near-infrared region of 800 to 1200 nm when measured with a spectrophotometer or the like. It can be used.

  As the infrared absorber, known materials can be used. Specific examples include, for example, a cyanine compound, a merocyanine compound, a benzenethiol-based nickel metal complex, a mercaptophenol-based metal complex, and an aromatic diamine-based metal complex. Nickel complex compounds, phthalocyanine compounds, anthraquinone compounds, naphthalocyanine compounds, croconium compounds, aminium compounds, diimonium compounds, and the like can be used.

Furthermore, nickel metal complex infrared absorbers (Mitsui Chemicals, trade names: SIR-130, SIR-132), bis (dithiobenzyl) nickel (Midori Chemicals, trade name: MIR-101), bis [1 , 2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-102), tetra-n-butylammonium bis (cis-1,2-diphenyl- 1,2-ethylenedithiolate) nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-1011), tetra-n-butylammonium bis [1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate ] Nickel (manufactured by Midori Chemical Co., Ltd., trade name: MIR-1021), bis (4-tert-1,2-butyl-1,2-dithiophenolate) ni Kel-tetra-n-butylammonium (manufactured by Sumitomo Seika Co., Ltd., trade name: BBDT-NI), soluble phthalocyanine (manufactured by Nippon Shokubai Co., Ltd .: TX-305A), inorganic material system (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: ytterbium UU) -HP; manufactured by Sumitomo Metals Co., Ltd., indium tin oxide). These can be used in combination of two or more.
In the present invention, since it is preferable to produce a toner by preparing a master batch as described later, specific examples where it is preferable to use a thermally stable toner include a croconium-based compound (Fuji Photo Film). The product made by a company, brand name: ST-173), a naphthalocyanine compound (the Sanyo dye company make, brand name: SnNc FT-1), etc. are mentioned.

  Among these, when combined with the compound represented by the structural formula (1), it is more preferable to use a naphthalocyanine compound, a croconium compound, an aminium compound, or a diimonium compound.

  Addition of the infrared absorber improves fixability, but since the cost is high, it is desirable to reduce the addition amount of the infrared absorber as much as possible. Therefore, the combined use of the compound represented by the structural formula (1) as a fixing aid can reduce the amount of the infrared absorber added.

When the infrared absorber and the compound represented by the structural formula (1) are used in combination as the fixing aid, the mass ratio (infrared absorber / compound of the structural formula (1)) is 0.1 / 20-10. /0.5 is preferable, and 0.2 / 10 to 1/1 is more preferable.
The amount of the infrared absorber used in combination with the compound represented by the structural formula (1) is preferably in the range of 0.01 to 1% by mass in the total amount of the toner constituent components.

In addition, a charge control agent and wax can be used for the light fixing toner of the present embodiment, if necessary.
As the charge control agent, known calixarene, nigrosine dyes, quaternary ammonium salts, amino group-containing polymers, metal-containing azo dyes, salicylic acid complex compounds, phenol compounds, azochromes, azozincs, and the like can be used. In addition, magnetic materials such as iron powder, magnetite, and ferrite can be mixed in the toner, and magnetic toner can be used. In particular, in the case of a color toner, a known white magnetic powder (for example, manufactured by Nippon Steel Mining Co., Ltd.) can be used.

  As the wax to be contained in the photofixing toner of this embodiment, ester wax, polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene is most preferable, but polyglycerin wax, microcrystalline wax, paraffin wax, carnauba wax, sazol. Wax, montanic acid ester wax, deacidified carnauba wax, palmitic acid, stearic acid, montanic acid, brandic acid, eleostearic acid, valinalic acid and other unsaturated fatty acids, stearic alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol , Saturated alcohols such as ceryl alcohol, melyl alcohol, or long-chain alkyl alcohols having a long-chain alkyl group; polyhydric alcohols such as sorbitol Cole; fatty acid amides such as linoleic acid amide, oleic acid amide, lauric acid amide; saturated fatty acid bisamides such as methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, hexamethylene bisstearic acid amide Unsaturated fatty acid amides such as ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; Aromatic bisamides such as amides and N, N'-distearylisophthalic acid amides; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally referred to as metal soap); fats Obtained by grafting to aromatic hydrocarbon wax using vinyl monomers such as styrene and acrylic acid; partially esterified products of fatty acid and polyhydric alcohol such as behenic acid monoglyceride; obtained by hydrogenation of vegetable oil Examples include methyl ester compounds having a hydroxyl group.

As the wax that can be used in the photofixing toner of this embodiment, ester wax, polyethylene, polypropylene, or a copolymer of polyethylene and polypropylene is preferable.
These waxes can be used alone or in combination of two or more. The addition amount of the wax in the present embodiment is preferably in the range of 0.1 to 10 parts by mass, and in the range of 1 to 4 parts by mass with respect to 100 parts by mass of the finally produced toner particles. More preferred.

  In producing the above-described toner for photofixing, a commonly used kneading and pulverizing method, wet granulation method, or the like can be used. Here, as the wet granulation method, suspension polymerization method, emulsion polymerization method, emulsion polymerization aggregation method, soap-free emulsion polymerization method, non-aqueous dispersion polymerization method, in-situ polymerization method, interfacial polymerization method, emulsion dispersion granulation The law etc. can be used.

  In order to produce the photofixing toner of this embodiment by the kneading and pulverization method, a binder resin, an infrared absorber, an antioxidant, a wax, a charge control agent, a pigment or dye as a colorant, and other additives Are mixed thoroughly with a mixer such as a Henschel mixer and a ball mill, and melted and kneaded using a heat kneader such as a heating roll, kneader, and extruder to make the resins compatible with each other. A toner can be obtained by dispersing or dissolving an inhibitor, a pigment, a dye, a magnetic substance, etc., cooling and solidifying, and then pulverizing and classifying. Moreover, in order to improve the dispersibility of a pigment or an infrared absorber, you may perform a masterbatch.

On the other hand, as a wet granulation method, for example, when prepared by an emulsion polymerization method, first, a monomer such as styrene, butyl acrylate, or 2-ethylhexyl acrylate is dissolved in water in which a water-soluble polymerization initiator such as potassium persulfate is dissolved. In addition, a surfactant such as sodium dodecyl sulfate is added as necessary, and polymerization is performed by heating while stirring to obtain resin particles (resin particle forming step).
Thereafter, in addition to the colorant and infrared absorber described above, if necessary, a powder such as a charge control agent and a release agent composition is added to the suspension in which the resin particles are dispersed, and the pH of the suspension and the stirring strength are added. By adjusting the temperature and the like, the resin particles, the colorant powder, the infrared absorber powder and the like are heteroaggregated to obtain a heteroaggregate (aggregation step). Furthermore, the reaction system is heated to a temperature higher than the glass transition temperature of the resin particles to fuse the heteroaggregates to obtain colored particles (fusion process). Thereafter, the colored particles are washed and dried, and an external additive is added as necessary to obtain the photofixing toner of this embodiment.

  In the present embodiment, as described above, it is preferable to use a polyester resin as the binder resin. When the toner particles are formed by a wet method using the polyester resin as the binder resin, the emulsion aggregation method is employed. can do. In this case, the resin particle forming step is performed by applying a shear force to a solution obtained by mixing, for example, an aqueous medium, a sulfonated polyester resin and a mixed solution (polymer solution) containing a colorant as necessary. By giving an emulsified particle forming step of forming emulsified particles (droplets) by giving, colored particles can be similarly produced. The shape of the toner can be changed from a true sphere to a tuft of grapes.

The toner particles obtained by the above production method preferably have a volume average particle diameter D50v of 3 to 15 μm, more preferably 5 to 15 μm, and particularly preferably 5 to 10 μm.
If the volume average particle size of the toner particles exceeds 15 μm, the toner particle size may be large and an image with sufficient resolution may not be obtained. On the other hand, if the thickness is less than 3 μm, the resolution of the obtained image is high, but the fluidity is low, so the image is not stable and may cause fogging and poor cleaning.

In the present embodiment, white inorganic fine particles can be mixed with toner particles for a fluidity improver or the like. The mixing ratio with the toner particles is in the range of 0.01 to 5 parts by mass, preferably in the range of 0.01 to 2.0 parts by mass, with respect to 100 parts by mass of the toner particles. Examples of such inorganic fine powder include silica fine powder, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, and diatomaceous earth. Soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride and the like can be mentioned, and silica fine powder is particularly preferable. Moreover, well-known materials, such as a silica, titanium, resin fine powder, an alumina, can be used together. Further, as a cleaning activator, a metal salt of a higher fatty acid typified by zinc stearate and a fine powder of a fluorine-based high molecular weight substance may be added.
The toner of this embodiment can be obtained by sufficiently mixing the inorganic fine particles and, if necessary, desired additives with a mixer such as a Henschel mixer.

  The photofixing toner of the present invention is desirably a positively chargeable toner. The toner for photofixing is often used in a high-speed machine, and a positively charged photoconductor such as amorphous silicon is used as a photoconductor for the high-speed machine. Therefore, the toner for reversal development may be positively charged. This is desirable. In addition, since the compound represented by the structural formula (1) has positive chargeability as described above, excellent characteristics as a positively chargeable toner can be obtained by addition to the toner.

<Electrostatic image developer>
The electrostatic charge image developer (hereinafter sometimes abbreviated as “developer”) including the photofixing toner of the present invention is a one-component developer composed of the toner or a two-component developer composed of a carrier and the toner. Any of the agents may be used.
Examples of the carrier used as a two-component developer include a resin-coated carrier having a resin coating layer on the core material surface. As the core material, known magnetite, ferrite, and iron powder can be used. The carrier coating agent is not particularly limited, but a silicone resin system is particularly desirable from the viewpoint that positive chargeability can be maintained over time.

As an average particle diameter of a carrier core material, generally 10-100 micrometers is preferable and 20-80 micrometers is more preferable.
The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is in the range of toner: carrier = 1: 100 to 30: 100, more preferably in the range of 3: 100 to 20: 100. desirable.

<Process cartridge, image forming apparatus>
The image forming apparatus of the present invention is not particularly limited as long as it can form an image using a toner containing toner on a recording medium by using the developer containing the above-described toner for light fixing of the present invention. Specifically, the image forming apparatus includes at least a toner image forming unit that forms a toner image on a recording medium and a fixing unit that optically fixes the toner image on the recording medium.

  The image can be formed, for example, as follows when an electrophotographic photosensitive member is used as the electrostatic charge image holding member. First, the surface of the electrophotographic photosensitive member is uniformly charged by a corotron charger, a contact charger or the like and then exposed to form an electrostatic charge image. Next, the toner is attached to the electrostatic charge image by contacting or approaching with a developing roll (developer holding member) having a developer layer formed on the surface, and a toner image is formed on the electrophotographic photosensitive member. The formed toner image is transferred onto the surface of a recording medium such as paper using a corotron charger or the like. Further, the toner image transferred to the surface of the recording medium is fixed by a fixing device, and an image is formed on the recording medium.

  In this image forming apparatus, for example, the portion including the developing roll may have a cartridge structure (process cartridge) that is detachable from the main body of the image forming apparatus. As the process cartridge, a developer holding body is used. A process cartridge containing at least the electrostatic charge image developer of the present invention is preferably used.

  As the electrophotographic photoreceptor, generally, an inorganic photoreceptor such as amorphous silicon or selenium, or an organic photoreceptor using polysilane, phthalocyanine or the like as a charge generation material or a charge transport material can be used. Therefore, an amorphous silicon photoreceptor is preferable.

  The fixing device is not particularly limited as long as it can be fixed by light. When the toner for light fixing of the present invention is used, an optical fixing device (flash fixing device) is used.

Examples of the light source used in the optical fixing device include a normal halogen lamp, a mercury lamp, a flash lamp, an infrared laser, and the like, and it is optimal because energy can be saved by instantaneously fixing with a flash lamp. Preferably emission energy of the flash lamp is in the range of 1.0~7.0J / cm ^2, and more preferably in the range of 2~5J / cm ^2.

Here, the emission energy per unit area of flash light indicating the lamp intensity of xenon is expressed by the following equation (1).
S = ((1/2) × C × V ² ) / (u × L) × (n × f) (1)
In the above formula (1), n is the number of lamps that emit light at once (f), f is the lighting frequency (Hz), V is the input voltage (V), C is the capacitor capacity (F), u is the process transfer speed (cm / S), L represents the effective light emission width of the flash lamp (usually the maximum paper width, cm), and S represents the energy density (J / cm ² ).

The light fixing method may be a delay method in which a plurality of flash lamps emit light with a time difference. This delay system is a system in which a plurality of flash lamps are arranged, each lamp is delayed by about 0.01 to 100 ms, light is emitted, and the same portion is illuminated a plurality of times. As a result, the light energy can be divided and supplied to the toner image with a single light emission, so that the fixing conditions can be made mild and both void resistance and fixability can be achieved.
Here, when flash emission is performed on the toner a plurality of times, the emission energy of the flash lamp indicates the total amount of emission energy given to the unit area for each emission.

In the delay system, the number of flash lamps is preferably in the range of 1-20, and more preferably in the range of 2-10. Moreover, it is preferable that each time difference between several flash lamps is the range of 0.1-20 msec, and it is more preferable that it is the range of 1-3 msec.
Furthermore, once emission energy of light emitted in one flash lamp is preferably in the range of 0.1~1J / cm ^2, more preferably in the range of 0.4~0.8J / cm ^2.

Hereinafter, an embodiment of an image forming apparatus including an optical fixing device to which an optical fixing toner of the present invention is optically fixed will be described with reference to the drawings.
FIG. 1 is a schematic diagram illustrating an example of the image forming apparatus. FIG. 1 shows a toner image formed by toner obtained by adding black to three colors of cyan, magenta, and yellow.

  In FIG. 1, 1a to 1d are charging means, 2a to 2d are exposure means, 3a to 3d are electrostatic charge image carriers (photoconductors), 4a to 4d are developing means, 5a to 5d are color developing means, and 10 is a roll medium. 15, a cyan developing unit, 30 a magenta developing unit, 40 a yellow developing unit, 50 a black developing unit, 70a to 70d a transfer roll, and 71 and 72 a roll. , 80 represents a transfer voltage supply means, and 90 represents an optical fixing device (fixing means).

The image forming apparatus shown in FIG. 1 includes a developing unit (toner image forming unit) for each color indicated by reference numerals 20, 30, 40, and 50 including a charging unit, an exposure unit, a photosensitive member, and a developing unit, and a recording paper 10. Rolls 71 and 72 which are arranged in contact with each other and convey the recording paper 10; and transfer rolls 70a and 70b which are 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. 70c, 70d, transfer voltage supply means 80 for supplying voltage to these three transfer rolls, and the side of the recording paper 10 in contact with the photoconductor that passes through the nip portion between the photoconductor and the transfer roll in the direction of the arrow in the figure. And an optical fixing device (fixing means) 90 for irradiating light.
In FIG. 1, not only the developing means 4a to 4d but also the developing units 20 to 50 can be the process cartridge.

For example, the cyan developing unit 20 has a configuration in which a charging unit 1a, an exposing unit 2a, and a developing unit 4a are arranged around the photoreceptor 3a in a clockwise direction. Further, the transfer roll 70a is opposed to the photosensitive member 3a through the recording paper 10 so as to come into contact with the surface of the photosensitive member 3a from the position where the developing unit 4a of the photosensitive member 3a is arranged until the charging unit 1a is arranged clockwise. Is arranged.
In this configuration, an ultraviolet lamp as the color developing means 5a is arranged at the upper portion of the developing means 4a in the figure, and this ultraviolet lamp illuminates the inside of the developer storage portion of the developing means 4a, so that the fixing aid in the toner is changed. The developed color is developed on the photoreceptor 3a.

  Such a configuration is the same for the developing units of other colors. In the image forming apparatus shown in FIG. 1, the developer containing cyan toner is accommodated in the developing means 4a of the cyan developing unit 20, and the developing means of the other developing units correspond to the respective colors. A toner for light fixing is stored.

  Next, image formation using this image forming apparatus will be described. First, in the black developing unit 50, the surface of the photoreceptor 3d is uniformly charged by the charging unit 1d while rotating the photoreceptor 3d in the clockwise direction. Next, the surface of the charged photoreceptor 3d is exposed by the exposure means 2d, whereby a latent image corresponding to the yellow component image of the original image to be copied is formed on the surface of the photoreceptor 3d. Further, the black toner stored in the developing means 4d is applied on the latent image to develop it to form a black toner image. This process is similarly performed in the yellow developing unit 40, the magenta developing unit 30, and the cyan developing unit 20, and each color toner image 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 on the surface of the paper 10 and laminated in the order of cyan, magenta and yellow from the top layer.

  Next, the laminated toner image on the recording paper 10 is conveyed to the optical fixing device 90, where it is irradiated with light from the optical fixing device 90, melted, and optically fixed on the recording paper 10 to form a full color image. It is formed.

  The color toner for light fixing of the present invention can be suitably used for various applications such as newspapers, service bureaus, barcode printing, label printing, tag printing, Carlson type or ion flow type printers and copying. In particular, even in the colored embodiment, it is possible to provide a product that exhibits good flash fixability at low cost, and therefore can easily meet the demand for colorization of images in these applications.

<Manufacture of toner>
The compound represented by the structural formula (1) used in this example is the following compound (1). Moreover, the data of the differential scanning calorimetry of this compound (1) are shown in FIG. As shown in FIG. 2, this compound has an exothermic peak at 315 ° C.

  Next, based on the composition shown in Table 1, each toner raw material was put into a Henschel mixer and premixed, and then kneaded at 190 ° C. and 250 rpm with an extruder (Ikegai Co., Ltd., PCM-30). . Next, the mixture was coarsely pulverized with a hammer mill, finely pulverized with a jet mill, and then classified with an airflow classifier to obtain toner particles having a volume average particle diameter of 4.5 to 4.9 μm.

  Next, with respect to 98 parts by mass of each of these toner particles, 2.0 parts by mass of hydrophobic silica fine particles WA10459 (manufactured by Clariant) are externally added by a Henschel mixer (FM-75 type, manufactured by Mitsui Miike Chemical Co., Ltd.). Thus, the toners BU-1 to BU-10 for photofixing used in the respective examples and comparative examples were obtained.

In addition, when differential scanning calorimetry was performed on these toners under the above-described conditions, in the toners BU-2 to BU-8 and BU-10 containing the compound (1), an exothermic peak was observed at around 315 ° C. It was. Moreover, the calorific value was obtained from these exothermic peaks.
The results are summarized in Table 1.

<Production of developer>
A two-component developer was prepared using the obtained toner. As a carrier to be mixed with each toner, a carrier having a general-purpose volume average particle size of 40 μm coated with a silicone resin (SR2411 manufactured by Toray Dow Corning Silicone Co., Ltd.) was used. 95 parts of a carrier was mixed with 5 parts of each toner, and mixed for 2 hours in a 10 L ball mill to prepare 3.5 kg of each developer. Using the developer thus obtained, the fixability and color reproducibility were evaluated by the following methods.

<Examples 1-8, Comparative Examples 1-2>
Using each of the developers described above, image evaluation including fixability was performed. As an evaluation apparatus, a modified machine of Fuji Xerox 490/980 Continuous Feed printer manufactured by Fuji Xerox Co., Ltd. equipped with a xenon flash lamp as an optical fixing device (schematic configuration is the same as in FIG. 1) was used. The light emission energy of the flash lamp was 3.2 J / cm ² .

(Fixability evaluation)
Plain paper (NIP-1500LT, Kobayashi recording paper) was used as a recording medium, and an image of 1 inch square (2.54 cm × 2.54 cm) was formed by the image forming apparatus. Specifically, each of the photofixing toners shown in Table 1 is used, and the toner adhesion amount (toner applied amount on the recording medium) is adjusted to be 0.5 mg / cm ^{2 for} a single color, and image output is performed. went.

Next, the fixing rate of the obtained 1-inch square 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 this image, and after 1 minute, the adhesive tape is peeled off and peeled off. The status A density (OD2) of the subsequent image was measured. In addition, (X-rite 938) was used for the measurement of optical density. Next, the fixing rate was calculated from the following equation (2) using the obtained optical density value.
Fixing rate (%) = (OD2 / OD1) × 100 (2)

The fixing property was evaluated according to the following criteria for the fixing rate calculated from Equation (2).
A: The fixing rate is 90% or more.
A: The fixing rate is 80% or more and less than 90%.
Δ: The fixing rate is 70% or more and less than 80%.
X: Fixing rate is less than 70% (a level that is difficult to use).

(Toner charge measurement)
The image forming apparatus continuously prints 5000k sheets of 4% images, and collects about 0.3 to 0.7 g of developer from the sleeves in the developing unit at the initial stage and after 5000k sheets, at 25 ° C. and 55% RH. The toner charge amount was measured by a blow-off method using a charge amount measuring device (TB200, manufactured by Toshiba Corporation) under the above conditions. From the results, the amount of charge increased after printing was compared with the initial value.

(Image density)
For solid images similar to the above-mentioned fixability evaluation, the image density at the initial stage and after printing 5000 k sheets was measured with an image densitometer X-Rite 938 (manufactured by X-Rite), and the density decreased after printing was compared with the initial density. .

(image quality)
Regarding the image quality, after printing 5000k sheets, an image combining a solid image and a halftone image was printed and evaluated according to the following criteria.
○: There is no scattering of toner, and the density uniformity is good. In addition, the image density change is 0.1 or less.
Δ: Toner scattering and density unevenness are slightly present, but within a practically acceptable range. The image density change is 0.1 to 0.2.
X: Toner scattering, density unevenness, image density change is 0.2 or more, and there are practical problems.
The above results are summarized in Table 2.

<Comparative Example 3>
Toner BU-5 was produced in the same manner except that 5 parts by mass of 2,2′-azobis (2-cyanobutane) was used instead of 5 parts by mass of Compound (1). At this time, since the kneaded product generated heat during the toner kneading, the kneading was carried out while maintaining 190 ° C. while cooling with a large amount of cold water. As a result, a toner could be obtained, but no exothermic peak was obtained in differential scanning calorimetry.
Further, the fixing property was evaluated according to the above, but the fixing rate was about 50%, which was poor.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a DSC curve of the compound (1) used in the Example.

Explanation of symbols

1a, 1b, 1c, 1d Charging means 2a, 2b, 2c, 2d Exposure means 3a, 3b, 3c, 3d Photoconductors 4a, 4b, 4c, 4d Developing means 5a, 5b, 5c, 5d Coloring means 10 Recording paper (recording) Medium)
20 Cyan developing unit 30 Magenta developing unit 40 Yellow developing unit 50 Black developing units 70a, 70b, 70c, 70d Transfer roll 71, 72 Roll 80 Transfer voltage supply means 90 Optical fixing device (fixing means)

Claims (10)

A photofixing toner comprising a binder resin and a compound represented by the following structural formula (1):

(In the above formula, R ¹ and R ² each independently represent hydrogen or an alkyl group having 1 to 8 carbon atoms, and R ³ represents an alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted carbon group having 5 to 7 carbon atoms. (It represents a cycloalkyl group, and each of the substituents is independently a chlorine atom, a bromine atom or a benzyl group or a phenyl group which may have an alkyl group having 1 to 4 carbon atoms.) The photofixing toner according to claim 1, wherein the compound represented by the structural formula (1) is the following compound (1).

  3. The photofixing toner according to claim 1, wherein the content of the compound is in the range of 0.5 to 20 mass% in the whole toner.   4. The photofixing toner according to claim 1, which has an exothermic peak in a range of 200 to 350 ° C. in differential scanning calorimetry. 5.   5. The photofixing toner according to claim 1, wherein the calorific value obtained from the exothermic peak is in the range of 1 to 35 mJ / mg.   6. The photofixing toner according to claim 1, wherein the colorant contains carbon black.   The photofixing toner according to claim 1, wherein the toner is a positively chargeable toner.   An electrostatic charge image developer comprising a toner, wherein the toner is the photofixing toner according to claim 1.   9. A process cartridge comprising at least a developer holder and containing the electrostatic charge image developer according to claim 8. A toner image forming means for forming a toner image on a recording medium with a developer containing toner, and a fixing means for fixing the toner image on the recording medium with light,
An image forming apparatus, wherein the developer is the electrostatic charge image developer according to claim 8.

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