JP2010079077A - Developing agent for developing electrostatic image, cartridge of the same, process cartridge, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic image developing agent which reduces the scattering carriers, uneven image densities, and brush marks (phenomenon that the magnetic brush leaves its traces on the image). <P>SOLUTION: The electrostatic image developing agent contains a toner including toner particles, spherical external additives of an 80 nm or larger and 200 nm or smaller average volume size, indeterminable external additives with indeterminable shapes, and carriers of a 45 μm or larger and 75 μm or smaller average volume particle size with a saturated magnetization of 70 Am<SP>2</SP>/kg or larger and 95 Am<SP>2</SP>/kg or smaller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  For example, an image forming apparatus using electrophotography has been conventionally known. In general, an electrophotographic image forming apparatus is implemented as follows. First, an electrostatic latent image is electrically formed by various means on the surface of a photoreceptor (electrostatic latent image holding body) using a photoconductive substance. Subsequently, the electrostatic latent image is developed with a developer containing toner to form a toner image. Thereafter, the toner image is transferred onto the surface of a recording medium such as paper, optionally via an intermediate transfer member. Then, by fixing the toner image transferred to the surface of the recording medium, an image is formed on the surface of the recording medium. Further, the toner remaining on the surface of the photoreceptor is cleaned by various methods as necessary, and is used again for developing the toner image.

In this image forming apparatus, for example, for the purpose of suppressing image loss such as white spots due to carrier scattering on a high speed machine or carrier flying on the latent image holding body, the developer amount and magnetic flux on the developer holding body. The proposal which prescribed | regulated the density was made | formed (refer patent document 1). In addition, it has been proposed to prevent white spots and carrier flying in a solid image by changing the position of a developer head (so-called magnetic brush) on the developer holder (for example, Patent Document 2). reference)
JP 2003-255711 A JP 2006-72312 A

  An object of the present invention is to provide a developer for electrostatic charge development in which carrier scattering is suppressed and generation of density unevenness and brush marks (a phenomenon in which a magnetic brush remains in an image) is suppressed.

The above problem is solved by the following means. That is,
The invention according to claim 1
A toner containing toner particles, a spherical external additive having a volume average particle diameter of 80 nm to 200 nm, and an amorphous external additive having an irregular shape;
A carrier having a volume average particle diameter of 45 μm or more and 75 μm or less and a saturation magnetization of 70 A · m ² / kg or more and 95 A · m ² / kg or less;
A developer for developing an electrostatic charge.

The invention according to claim 2
The developer for electrostatic charge development according to claim 1, wherein the addition amount of the spherical external additive to the toner particles is larger than the addition amount of the amorphous external additive to the toner particles.

The invention according to claim 3
2. The static electricity according to claim 1, wherein a ratio of an addition amount of the spherical external additive to the toner particles and an addition amount of the amorphous external additive to the toner particles is 100: 5 to 100: 90. Developer for charge development.

The invention according to claim 4
The developer for electrostatic charge development according to claim 1, wherein an addition amount of the spherical external additive to the toner particles is 0.01% by mass or more and 10.00% by mass or less.

The invention according to claim 5
The developer for electrostatic charge development according to claim 1, wherein an amount of the amorphous external additive added to the toner particles is 0.02% by mass or more and 10.00% by mass or less.

The invention according to claim 6
The electrostatic charge developing developer according to claim 1, wherein the amorphous external additive has a shape factor SF1 of 135 or more and 190 or less.

The invention according to claim 7 provides:
2. The developer for electrostatic charge development according to claim 1, wherein a difference in shape factor SF <b> 1 between the spherical external additive and the amorphous external additive is 15 or more and 70 or less.

The invention according to claim 8 provides:
Contains a developer that is detached from the image forming apparatus and supplied to at least developing means provided in the image forming apparatus;
A developer cartridge for developing an electrostatic charge image, wherein the developer is the developer for developing an electrostatic charge image according to any one of claims 1 to 7.

The invention according to claim 9 is:
A developer for developing an electrostatic charge image according to any one of claims 1 to 7, wherein the developer for developing an electrostatic charge image is formed on an electrostatic latent image formed on the surface of the electrostatic latent image holding member. Developing means for developing the toner image by:
At least one selected from the group consisting of an electrostatic latent image holding body, a charging means for charging the electrostatic latent image holding body, and a toner removing means for removing toner remaining on the surface of the electrostatic latent image holding body And comprising
A process cartridge that is detachable from the main body of the image forming apparatus.

The invention according to claim 10 is:
An electrostatic latent image carrier;
Charging means for charging the surface of the electrostatic latent image holding member;
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrostatic latent image holding member;
A developing means for developing the electrostatic latent image into a toner image with a developer, the developer holding body disposed opposite to the electrostatic latent image holding body;
Transfer means for transferring the toner image formed on the surface of the electrostatic latent image holding member to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the recording medium;
With
An image forming apparatus, wherein the developer is the developer for developing an electrostatic image according to any one of claims 1 to 7.

The invention according to claim 11 is:
The image forming apparatus according to claim 10, wherein the latent image holder and the developer holder are rotated in the same direction.

The invention according to claim 12
The image forming apparatus according to claim 10, wherein a process speed is 700 mm / sec or more.

According to the first aspect of the present invention, carrier scattering is suppressed and the occurrence of density unevenness and brush marks (a phenomenon in which the marks of the magnetic brush remain in the image) are suppressed as compared with the case where this configuration is not provided. .
According to the second aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (magnetic brush traces) are suppressed as compared with the case where the addition amounts of the spherical external additive and the irregular external additive are not taken into consideration. Occurrence of a phenomenon that remains in an image) is suppressed.
According to the third aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (magnetic brush traces) are suppressed as compared with the case where the addition amount of the spherical external additive and the irregular external additive is not taken into consideration. Occurrence of a phenomenon that remains in an image) is suppressed.
According to the fourth aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which the traces of a magnetic brush remain in an image) are suppressed as compared with a case where the addition amount of the spherical external additive of the toner is not taken into consideration. Is suppressed.
According to the fifth aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which a magnetic brush trace remains in an image) are compared with a case where the amount of the toner's amorphous external additive added is not taken into consideration. ) Is suppressed.
According to the sixth aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which a trace of a magnetic brush remains in an image) as compared with a case where the shape factor of an irregular external toner additive is not considered. ) Is suppressed.
According to the seventh aspect of the present invention, carrier scattering is suppressed and density unevenness and brush marks (magnetic brushes) are compared with the case where the difference in shape factor between the spherical external additive and the amorphous external additive is not taken into consideration. Occurrence of a phenomenon in which the trace of the image remains in the image is suppressed.
According to the eighth aspect of the present invention, carrier scattering is suppressed and generation of density unevenness and brush marks (a phenomenon in which a magnetic brush mark remains in an image) is suppressed as compared with the case where the present configuration is not provided. .
According to the ninth aspect of the present invention, carrier scattering is suppressed and occurrence of density unevenness and brush marks (a phenomenon in which a magnetic brush mark remains in an image) is suppressed as compared with the case where the present configuration is not provided. .
According to the tenth aspect of the present invention, carrier scattering is suppressed and occurrence of density unevenness and brush marks (a phenomenon in which the marks of the magnetic brush remain in the image) are suppressed as compared with the case where the present configuration is not provided. .
According to the eleventh aspect of the invention, even when the rotation directions of the latent image holding member and the developer holding member are the same, carrier scattering is suppressed.
According to the twelfth aspect of the present invention, carrier scattering is suppressed even when the process speed is higher than a specific value.

  Hereinafter, embodiments of the present invention will be described.

[Developer]
The developer for electrostatic charge development according to this embodiment (hereinafter referred to as a developer)
A toner comprising toner particles, a spherical external additive having a volume average particle diameter of 80 nm to 200 nm, and an amorphous external additive having an irregular shape;
A carrier having a volume average particle diameter of 45 μm or more and 75 μm or less and a saturation magnetization of 70 A · m ² / kg or more and 95 A · m ² / kg or less;
Have

  Here, it is known that carrier scattering (flying) occurs in the development of an electrostatic latent image with a developer containing toner and carrier. For example, the electrostatic latent image holding member and the developing unit are particularly used as means for increasing the amount of toner supplied to the developing nip (opposite portion between the latent image holding member and the developer holding member) for the purpose of securing the density of the solid image. When there is a difference in the peripheral speed of the developer carrier, or when the latent image carrier and the developer carrier are opposed to each other with their rotation directions opposite to each other, the developer spikes on the developer carrier and the latent image When the carrier comes into contact, the carrier is blown out of the developing machine due to the difference in speed between the two and the surroundings of the developing machine are contaminated, or the scattered carrier bites into bearings, gears, etc., causing failure There is. Furthermore, when the developer is used over a long period of time, the amount of the developer gradually decreases due to carrier scattering, which may cause a problem that the development amount cannot be maintained. In particular, a high-speed machine (for example, a process speed of 700 mm / sec or more) in which the rotational speed of the latent image holding member and the developer holding member is high, or a tangential vector at the development nip portion between the developer holding member and the latent image holding member. In the development where so is reversed (so-called against development), the scattering of the carrier (depletion of the developer) becomes more remarkable.

  Suppressing carrier scattering (depressing the decrease in developer) is not sufficient, although some improvement can be seen by increasing the magnetic force of carrier magnetization and developer holder and improving the magnetic binding force. There is also a technical limit to the rise. In particular, suppression of carrier scattering by contact is difficult at present only by increasing carrier magnetization.

  On the other hand, an increase in carrier magnetization, especially when used for a long period of time, causes a decrease in charge amount and a low toner density in the developer. May occur easily. This is because the rising of the magnetic force of the carrier magnetization hardens the rising of the developer on the developer holding member, and the scavenging of the developed image on the latent image holding member that occurs simultaneously with the development becomes stronger. It is considered that the phenomenon that the trace of the magnetic brush remains in the image occurs.

  Therefore, in the developer according to the present embodiment, the above-described configuration suppresses carrier scattering, as well as density unevenness and brush marks (the marks of the magnetic brush remain in the image), compared to the case without the configuration. Phenomenon) is suppressed. This is because the developer having the above-described configuration has an appropriate flexibility of the developer spike on the developer holder, and when the developer comes into contact with the electrostatic latent image holder, the impact is passed through the entire spike. it is conceivable that. The reason why the developer having the above-described configuration has appropriate flexibility in the appearance of the developer and exhibits the above effect is not clear, but is considered to be as follows.

  First, as a carrier, in order to suppress white spots and density unevenness, the above-mentioned specific volume average particle diameter is used, and a developer spike (magnetic brush) that is not easily defeated by the centrifugal force accompanying the rotation of the developer holder is used. A carrier having the specific saturation magnetization is employed in order to facilitate the formation and suppress the decrease in the flexibility of the rising of the developer.

  On the other hand, it is considered that the use of a toner containing two types of specific spherical external additive and specific irregular external additive together with the carrier gives appropriate flexibility to the rising of the developer. It is done. This is because, by using two specific types of external additives in combination as the external additive of the toner, it is considered that the developer forms moderately flexible spikes when the developer spikes are formed. It is.

This moderately flexible heading state is considered similar to the apparent density in the state where the carrier is subjected to magnetic restraining force on the developer holding member, It is considered that the carrier and the toner are densely present, and the amount of toner supply increases, while the rise of the developer becomes hard, and it is difficult to be deformed by an external force such as contact with the latent image holding member. As a result, when a solid image is developed, an image defect called a so-called brush mark is generated, in which a trace of spikes remains in the developed image. On the other hand, if the flexibility becomes excessively high, the rise of the developer becomes soft and brush marks are less likely to be generated.However, due to the insufficient amount of toner supplied to the developing section, the density decreases and the solid image Image quality defects such as density unevenness are likely to occur.
In other words, it is important to maintain the state of the rising of the developer in an appropriate state over time.

  Of the two types of external additives, the spherical external additive is considered to have a role of keeping the developer heading in an appropriate state, and it is easy to keep the developer in an appropriate state. Become. On the other hand, it is considered that the charge amount of the developer (toner) is changed due to use over a long period of time or changes in the use environment, and as a result, the toner density is constantly changing. In particular, in a long-term use, the toner density gradually decreases due to a decrease in the charge imparting ability of the carrier, and as a result, the apparent density of the developer rises and tends to become a spike of hard developer.

  For this reason, by using an amorphous external additive together with the spherical external additive, a void is formed in the developer at the time of the formation of the spike of the developer, and even when the toner concentration becomes low, the appearance of the developer is apparent. It is thought that the increase in the density of is suppressed.

  For the above reasons, in the developer according to the present embodiment, carrier scattering is suppressed and the occurrence of density unevenness and brush marks (a phenomenon in which a magnetic brush mark remains in an image) is suppressed by the above configuration.

  Hereinafter, each configuration of the developer according to the exemplary embodiment will be described.

(toner)
The toner includes toner particles, a spherical external additive, and an amorphous external additive. The toner particles include, for example, a binder, a colorant, and other additives as necessary.

-Binder resin-
As the binder resin, a known binder resin is used. As the main component of the binder resin, for example, a polyester resin and a polyolefin resin are desirable, but a copolymer of styrene and acrylic acid or methacrylic acid, 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. are used alone or in combination.
Among these, it is desirable to use a polyester resin from the viewpoint of easily increasing the image strength after fixing.

  The polyester resin as the binder resin will be further described. The acid component used in the polyester resin includes, for example, terephthalic acid, isophthalic acid, orthophthalic acid, or anhydrides thereof, and preferably terephthalic acid / isophthalic acid. It is. These acid components may be used alone or in combination of two or more. Other acid components may be used in combination with the above acid components. In particular, in the case of flash fixing (light fixing), other acid components are used in combination within a range where odor does not cause a problem. 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. -Butyl succinic acid, n-butenyl succinic acid, isobutyl succinic acid, isobutenyl succinic acid, n-octyl succinic acid, n-octenyl succinic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, isododecyl succinic acid, isododecenyl Examples also include alkyl or alkenyl succinic acids such as succinic acid, anhydrides of these acids, lower alkyl esters, and other divalent carboxylic acids. In order to crosslink the polyester resin, a trivalent or higher carboxylic acid component may 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.

  In addition, in this polyester resin, usually, 80 mol% or more of the alcohol component is composed of a bisphenol A alkylene oxide adduct, desirably 90 mol% or more, and more desirably 95 mol%. If the amount of the bisphenol A alkylene oxide adduct is less than 80 mol%, the amount of the monomer that causes odor generation is relatively large, which is not desirable.

  Examples of the bisphenol A alkylene oxide adduct include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3.3) -2,2-bis (4). -Hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxypropylene (2.0) -polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane Etc. These compounds may be used alone or in combination of two or more.

  In the polyester resin, if necessary, another alcohol component may be used in combination with the above alcohol component. Examples of other alcohol components include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-butenediol, 1 , 5-pentanediol, diols such as 1,6-hexanediol, and other dihydric alcohols such as bisphenol A and hydrogenated bisphenol A.

  In addition, trihydric or higher alcohols are also suitable as other alcohol components. Examples of the alcohol component include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1, Examples include 2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and other trivalent or higher alcohols.

  In the reaction for synthesizing the polyester resin, it is preferable to use a commonly used esterification catalyst such as zinc oxide, stannous oxide, dibutyltin oxide, dibutyltin dilaurate, etc. in order to accelerate the reaction. .

  The glass transition temperature Tg of the binder resin is desirably in the range of 50 ° C. or higher and 80 ° C. or lower.

-Colorant-
As the colorant, those shown below are selected and used corresponding 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 phthalocyanine blue, fast sky blue, indanthrene blue BC cyan pigment, C.I. I. Cyan dyes such as solvent cyan 79 and 162 are 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, 70, 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 are used.

In the yellow toner, as the colorant, for example, C.I. I. Pigment Yellow 2, 3, 15, 15, 17, 74, 97, 180, 185, 139, and the like are used.
In the black toner, as the colorant, for example, carbon black, activated carbon, titanium black, magnetic powder, Mn-containing nonmagnetic powder, or the like is used. Further, black toner may be obtained by mixing yellow, magenta, cyan, red, green, and blue pigments.

  The amount of each colorant added is desirably in the range of 1% by mass to 20% by mass in the final toner prepared by mixing with a binder resin or the like.

-Other additives-
Examples of other additives contained in the toner particles include waxes, charge control agents, infrared absorbers, and the like.

  As the wax, 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 ester wax, deacidified carnauba wax. , Unsaturated fatty acids such as palmitic acid, stearic acid, montanic acid, brandic acid, eleostearic acid, valinalic acid, stearyl alcohol, aralkyl alcohol, behenyl alcohol, carnauvir alcohol, ceryl alcohol, melyl alcohol, or even longer Saturated alcohols such as long-chain alkyl alcohols having a chain alkyl group; polyhydric alcohols such as sorbitol; linoleic acid amide, oleic acid Fatty acid amides such as amide and lauric acid amide; methylene bis stearic acid amide, ethylene biscapric acid amide, ethylene bis lauric acid amide, saturated fatty acid bisamides such as hexamethylene bis stearic acid amide, ethylene bisoleic acid amide, hexamethylene Unsaturated fatty acid amides such as bisoleic acid amide, N, N′-dioleyl adipic acid amide, N, N′-dioleyl sebacic acid amide; m-xylene bisstearic acid amide, N, N′-distearyl Aromatic bisamides such as isophthalamide; fatty acid metal salts such as calcium stearate, calcium laurate, zinc stearate and magnesium stearate (generally called metal soap); styrene and acrylic on aliphatic hydrocarbon waxes Waxes grafted with vinyl monomers such as acids; fatty acid esters such as behenic acid monoglycerides and partially esterified products of polyhydric alcohols; methyl ester compounds having hydroxyl groups obtained by hydrogenation of vegetable oils, etc. Can be mentioned.

As the wax, a wax material having an endothermic peak at 50 ° C. to 90 ° C. in differential scanning calorimetry (DSC) is desirable. If the peak temperature is lower than 50 ° C., the toner may be blocked, and if it is higher than 90 ° C., the toner may not be able to contribute to improvement of the fixability.
The DSC is preferably measured with a highly accurate internal heating input compensation type differential scanning calorimeter from the measurement principle, and is performed from room temperature (25 ° C.) at a heating rate of 10 ° C./min.

  The addition amount of the wax is preferably 0.5% by mass or more and 7% by mass or less in the whole toner particles, and more preferably 2% by mass or more and 4% by mass or less.

  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, etc. are used. . In addition, the toner may be mixed with a magnetic material such as iron powder, magnetite, or ferrite and used as a magnetic toner. In particular, in the case of a color toner, a known white magnetic powder (for example, manufactured by Nippon Steel Mining Co., Ltd.) is used.

  For example, when the developer (toner) according to this embodiment is used for light fixing such as flash fixing, the infrared absorber is usually preferably used together with the colorant. Here, the infrared absorber refers to, for example, a material having at least one strong light absorption peak in the near infrared region of 800 nm to 2000 nm when measured with a spectrophotometer or the like. Can be used.

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

  More specifically, as the infrared absorber, a cyanine-based infrared absorber (manufactured by Fuji Photo Film Co., Ltd., trade names: CTP-1, IRF-106, IRF-107), a cyanine compound (manufactured by Nippon Kayaku Co., Ltd., trade name: (CY-2, CY-4, CY-9), nickel metal complex infrared absorber (Mitsui Chemicals, trade names: SIR-130, SIR-132), bis (dithiobenzyl) nickel (manufactured by Midori Chemical Co., Ltd.) Trade name: MIR-101), bis [1,2-bis (p-methoxyphenyl) -1,2-ethylenedithiolate] nickel (manufactured by Midori Chemical Co., trade name: MIR-102), tetra-n-butyl Ammonium 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) nickel-tetra-n-butylammonium (manufactured by Sumitomo Seika Chemicals, trade name: BBDT-NI), soluble phthalocyanine (manufactured by Nippon Shokubai Co., Ltd .: TX-305A), naphthalocyanine (manufactured by Sanyo Color Co., Ltd.) , SnNc FT-1), inorganic materials (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: ytterbium UU-HP; manufactured by Sumitomo Metals Co., Ltd., indium tin oxide) and the like. Two or more of these may be used in combination.

  The addition amount of the infrared absorber is desirably in the range of 0.01% by mass to 5% by mass in the whole toner particles, and more desirably in the range of 0.1% by mass to 5% by mass. If 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.

-Toner particle characteristics-
The toner particles preferably have a volume average particle diameter D50v in the range of 3 μm to 10 μm, and more preferably in the range of 4 μm to 8 μm.

For the volume average particle size and particle size distribution index of the toner particles in this embodiment, Coulter Multisizer-II type (manufactured by Beckman Coulter Co.) is used as a measuring device, and the electrolyte is ISOTON-II (Beckman Coulter Corp.). Made).
As a measuring method, 0.5 mg to 50 mg of a measurement sample is added to 2 ml of a 5% by weight aqueous solution of a surfactant as a dispersant, preferably sodium alkylbenzenesulfonate. This was added to 100 ml to 150 ml of the electrolytic solution. The electrolytic solution in which the sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2 μm to 60 μm is measured using the Coulter Multisizer-II type with an aperture diameter of 100 μm. The volume average particle diameter D50v was determined. The number of particles to be measured was 50,000.

-External additive-
As the external additive, a spherical external additive and an amorphous external additive are used in combination. First, the spherical external additive will be described.

  The spherical external additive is a particle having a volume average particle diameter of 80 nm to 200 nm, preferably 80 nm to 180 nm, more preferably 90 nm to 170 nm, and most preferably 100 nm to 160 nm. . When this volume average particle diameter is smaller than 80 nm, the packing density becomes too high, and the deterioration of the brush mark over time is observed as described above. On the other hand, if the volume average particle diameter is larger than 200 nm, the packing is lowered, causing carrier scattering and density unevenness.

  The spherical external additive may have a shape factor SF1 of 100 to 130, preferably 100 to 125, and more preferably 100 to 123.

The material of the spherical external additive is not particularly limited, and examples thereof include organic particles and inorganic particles, and these may be used in combination.
Examples of inorganic particles include silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, chromium oxide, and oxidation. Examples thereof include cerium, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Silica is particularly desirable.
Examples of the resin particles include resin particles such as polystyrene, polymethyl methacrylate, and melamine resin.

  The addition amount (external addition amount) of the spherical particles is 0.01% by mass or more and 10.00% by mass or less, desirably 0.05% by mass or more and 5.0% by mass or less, more desirably 0% by mass with respect to the toner particles. It is good that it is in the range of 0.05 mass% to 4.0 mass%, most desirably 0.08 mass% to 3.5 mass%. By making this addition amount in the above range, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which a magnetic brush trace remains in an image) are compared with the case where the addition amount of the spherical external additive of the toner is not taken into consideration. ) Is suppressed.

  On the other hand, the amorphous external additive has a volume average particle size of 0.03 to 5.0 μm, preferably 0.05 to 4.0 μm, more preferably 0.08 to 4.0 μm, most preferably The particles may be in the range of 0.08 μm to 3.8 μm. When the volume average particle diameter is smaller than 0.03 μm, voids may be difficult to be generated when the toner concentration is low (for example, when the toner concentration is 2.0% by mass or less). On the other hand, when the volume average particle diameter exceeds 5.0 μm, it may be difficult to form a spike of the developer in a uniform state.

  The amorphous external additive has a shape factor SF1 of 135 to 190, preferably 135 to 180. By making the shape factor within the above range, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which a magnetic brush trace remains in an image) are compared to a case where the shape factor of an irregular external toner additive is not considered. ) Is suppressed. In particular, when the shape factor is less than 135, it is difficult to form voids in the developer when the toner concentration is lowered, and the packing of the developer spikes may increase. On the other hand, when the shape factor exceeds 190, for example, when the toner concentration increases under a low temperature and low humidity environment (for example, 10 ° C. and 15% RH), the packing state of the developer spike may be excessively lowered. , May cause carrier scattering.

  Examples of the material for the amorphous external additive include organic particles and inorganic particles as in the case of the spherical particles, and these may be used in combination.

  The amount of the external additive added (external addition amount) is 0.02% by mass or more and 10.00% by mass or less, preferably 0.02% by mass or more and 7.00% by mass or less based on the toner particles. The range is desirably 0.03% by mass or more and 5.00% by mass or less, and most desirably 0.05% by mass or more and 4.50% by mass or less. By making this addition amount within the above range, carrier scattering is suppressed and density unevenness and brush marks (the traces of the magnetic brush remain in the image) as compared with the case where the addition amount of the amorphous external additive of the toner is not taken into consideration. Phenomenon) is suppressed.

  Here, the addition amount of the spherical external additive to the toner particles is preferably larger than the addition amount of the amorphous external additive to the toner particles. Specifically, for example, the ratio of the addition amount of the spherical external additive to the toner particles and the addition amount of the amorphous external additive to the toner particles is 100: 5 to 100: 90, preferably 100: 7 to 100. : 80, more preferably in the range of 100: 10 to 100: 70. Compared to the case where the addition amount of the spherical external additive and the irregular external additive is not taken into consideration, the carrier scattering is suppressed, and the occurrence of density unevenness and brush marks (a phenomenon in which the mark of the magnetic brush remains in the image) is also suppressed. Is done.

Further, the difference between the shape factor SF1 between the spherical external additive and the amorphous external additive is 15 or more and 70 or less,
The range is desirably 15 or more and 60 or less, and more desirably 20 or more and 50 or less. Compared to the case where the shape factor difference between the spherical external additive and the irregular external additive is not taken into account, carrier scattering is suppressed and density unevenness and brush marks (a phenomenon in which a magnetic brush trace remains in an image) are generated. Is suppressed.

  Here, the volume average particle diameter of the external additive is measured using a laser diffraction / scattering type particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER). 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.

Further, the shape factor SF1 of the external additive is obtained by the following formula.
Formula: SF1 = (ML ² / A) × (π / 4) × 100
In the above formula (1), ML represents the absolute maximum length of the toner particles, and A represents the projected area of the toner particles.
The shape factor SF1 is obtained mainly by taking a scanning electron microscope (Hitachi, Ltd .; S-4100) image into an image analyzer (Luzex image analyzer), and obtaining the maximum length and projection area of 100 particles. ) And obtaining the average value.

-Toner production method-
The toner is obtained, for example, by preparing toner particles and then mixing with an external additive by a mixer such as a Henschel mixer.

The toner particles are produced by a method similar to a known toner production method such as a pulverization method or a polymerization method.
When using the pulverization method, for example, first, a binder resin (binder resin) is mixed with components such as a colorant, a wax composition, and a charge control agent as necessary, and then a kneader, an extruder, or the like is used. Used to melt knead the above materials. Thereafter, the obtained melt-kneaded product is coarsely pulverized and then finely pulverized with a jet mill or the like, and toner particles having a target particle diameter are obtained with an air classifier. Furthermore, as a subsequent process, using a hybridization system (manufactured by Nara Machinery Co., Ltd.), a mechano-fusion system (manufactured by Hosokawa Micron Corporation), a kryptron system (manufactured by Kawasaki Heavy Industries, Ltd.), etc. The toner shape is adjusted. Moreover, you may implement spheroidization by a hot air as a post process. Furthermore, as a post process, the toner particle size distribution may be adjusted by performing a classification process with an air classifier or the like.

Moreover, when utilizing a polymerization method, a suspension polymerization method or an emulsion polymerization method is mainly utilized.
When using the suspension polymerization method, for example, first, in addition to a monomer such as styrene, butyl acrylate, 2-ethylhexyl acrylate, a crosslinking agent such as divinylbenzene, a chain transfer agent such as dodecyl mercaptan, a polymerization initiator, If necessary, a colorant, a charge control agent, a wax composition and the like are further mixed to prepare a monomer composition.

  Thereafter, the monomer composition is put into an aqueous phase containing a suspension stabilizer such as tricalcium phosphate and polyvinyl alcohol, and a surfactant, and a rotor-stator emulsifier, a high-pressure emulsifier, and an ultrasonic emulsifier. After preparing the emulsion using a machine, the monomer is polymerized by heating to obtain particles. After completion of the polymerization, the obtained particles are washed and dried, and an external additive is added as necessary to obtain toner particles.

In the case of using the emulsion polymerization method, for example, first, a monomer such as styrene, butyl acrylate, or 2-ethylhexyl acrylate is added to water in which a water-soluble polymerization initiator such as potassium persulfate is dissolved. Accordingly, a surfactant such as sodium dolesyl sulfate is added, and polymerization is performed by heating while stirring to obtain resin particles.
Thereafter, if necessary, powders such as a colorant, a charge control agent, and a wax composition are added to the suspension in which the resin particles are dispersed, and the pH, agitation strength, temperature, etc. of the suspension are adjusted to oxidize the resin particles. Heteroaggregates are obtained by heteroaggregating an alkali metal salt powder of polyethylene or the like. Furthermore, the reaction system is heated above the glass transition temperature of the resin particles to fuse the heteroaggregates to obtain toner particles. Thereafter, the toner particles are washed and dried.

(Career)
The carrier is a carrier having a specific volume average particle diameter and a specific saturation magnetization.

  The volume average particle diameter of the carrier is 45 μm or more and 75 μm or less, preferably 45 μm or more and 70 μm or less, and more preferably 45 μm or more and 65 μm or less. When the volume average particle diameter of the carrier is less than 45 μm, the carrier is easily developed, and image defects such as white spots are likely to occur. On the other hand, when the volume average particle diameter of the carrier is larger than 75 μm, the density of the spikes tends to be lowered, the image density is difficult to be obtained, and an image with uneven density tends to be formed.

  The volume average particle diameter of the carrier is measured using a laser diffraction / scattering particle size distribution analyzer (LS Particle Size Analyzer: LS13 320, manufactured by BECKMAN COULTER). 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.

The saturation magnetization of the carrier is 70 A · m ² / kg to 95 A · m ² / kg, preferably 75 A · m ² / kg to 95 A · m ² / kg, more preferably 80 A · m ² / kg. The above is 95 A · m ² / kg or less. When the saturation magnetization of the carrier is in the above range, it becomes easy to form a spike of developer that is not defeated by the centrifugal force accompanying the rotation of the developer holder. In particular, the peripheral speed increases due to the use of high-speed machines (for example, high-speed machines whose process speed exceeds 700 mm / sec), and even small machines due to higher speeds. It becomes easy to form a rising edge of the developer that is not defeated. When the saturation magnetization of the carrier is less than 70 A · m ² / kg, for example, the rising of the developer tends to be insufficient with respect to the centrifugal force associated with the rotation of the developer holding member, and the carrier tends to scatter. On the other hand, when the saturation magnetization of the carrier exceeds 95 A · m ² / kg, the magnetic binding force becomes too strong, the rise of the developer tends to become hard, and the flexibility of the rise of the developer tends to decrease. It may cause image defects such as brush marks. This saturation magnetization is controlled by the carrier material (particularly the core material).

  The saturation magnetization is a value obtained by measurement using a vibration sample type magnetic measurement apparatus VSMP10-15 (manufactured by Toei Kogyo Co., Ltd.). The measurement sample is packed in a cell having an inner diameter of 7 mm and a height of 5 mm and set in the apparatus. The measurement is performed by applying an applied magnetic field and sweeping to a maximum of 238.7 kA / m (3 k Oersted). Next, the applied magnetic field is decreased to create a hysteresis curve on the recording paper. Saturation magnetization, residual magnetization, and coercive force are obtained from the curve data. Saturation magnetization is measured in a magnetic field of 238.7 kA / m (3 k Oersted)

  There is no restriction | limiting in particular as a structure of a carrier, For example, a well-known carrier is used. Examples of the carrier include a resin-coated carrier having a resin coating layer on the core material surface. The carrier may be a resin-dispersed carrier in which a conductive material or the like is dispersed in a matrix resin.

  Coating resins and matrix resins used for carriers include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic. Examples include, but are not limited to, acid copolymers, straight silicone resins composed of organosiloxane bonds or modified products thereof, fluororesins, polyesters, polycarbonates, phenol resins, and epoxy resins.

  Examples of the conductive material used for the carrier coating agent include metals such as gold, silver, and copper, and carbon black, as well as titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, tin oxide, and carbon black. However, it is not limited to these.

  Examples of the carrier core material include magnetic metals such as iron, nickel, and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. However, in order to use the carrier for the magnetic brush method, the carrier must be a magnetic material. Is desirable. More preferable as a carrier core material is a ferrite containing calcium, manganese, magnesium, copper, nickel, zinc and the like, and further a ferrite containing manganese and magnesium is preferable from the viewpoint that flexibility of earing is easily obtained. Used. The volume average particle diameter of the carrier core material is generally 10 μm or more and 500 μm or less, and preferably 20 μm or more and 90 μm or less.

  In order to coat the surface of the core material of the carrier with a resin, a method of coating with a coating layer forming solution in which the coating resin and, if necessary, various additives are dissolved in an appropriate solvent can be mentioned. The solvent is not particularly limited and may be appropriately selected in consideration of the coating resin to be used, coating suitability, and the like.

  Specific resin coating methods include an immersion method in which the carrier core material is immersed in the coating layer forming solution, a spray method in which the coating layer forming solution is sprayed onto the surface of the carrier core material, and the carrier core material is fluidized air. And a kneader coater method in which the carrier core material and the coating layer forming solution are mixed in a kneader coater and the solvent is removed in a kneader coater.

  Here, in the developer according to the present embodiment, the toner concentration in the developer always changes with changes in the charge imparting ability of the carrier and is not constant. Although not specified, for example, in normal use, it is preferably controlled within a range of 2.0% by mass or more and 15.0% by mass or less, and more preferably 2.0% by mass or more and 10.0% by mass. % Or less, more desirably 2.0% by mass or more and 8.0% by mass or less, and most desirably 2.0% by mass or more and 7.0% by mass or less. When the toner concentration is less than 2.0% by mass, the toner supply amount tends to be insufficient, and the density is likely to be lowered in a solid image or the like. On the other hand, if the toner concentration exceeds 15% by mass, the rise of toner charge tends to be slow when toner is added to the developer, and as a result, fog and cloud are likely to occur.

  The mixing ratio (mass ratio) of the toner and the carrier is in the range of toner: carrier = 1: 100 to 30: 100, and more preferably in the range of 3: 100 to 20: 100.

[Image forming apparatus]
The image forming apparatus of the present embodiment is not particularly limited as long as it can form a fixed image of a toner image on a recording medium using the developer according to the present embodiment. A charging unit that charges the surface of the electrostatic latent image holding member, an electrostatic latent image forming unit that forms an electrostatic latent image on the surface of the electrostatic latent image holding member, and a development arranged to face the electrostatic latent image holding member A developing means for developing the electrostatic latent image into a toner image with a developer, and a transfer means for transferring the toner image formed on the surface of the electrostatic latent image holding body to the surface of the recording medium. And an image forming apparatus including a fixing unit that fixes the toner image transferred to the recording medium.

  Image formation in the image forming apparatus of this embodiment is performed, for example, as follows when an electrophotographic photosensitive member is used as the electrostatic latent image holding member. First, the surface of the electrophotographic photosensitive member is 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 latent image in contact with or in proximity to a developing roll having a developer layer formed on the surface, thereby forming a toner image 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.

  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 is used. In particular, as an electrophotographic photosensitive member, from the viewpoint of abrasion resistance, an amorphous silicon photosensitive member is used for an inorganic photosensitive member, and a resin having a crosslinked structure such as a melamine resin, a phenol resin, or a silicone resin on the outermost layer if an organic photosensitive member is used. A photoreceptor having a so-called overcoat layer having a layer is desirable.

  The fixing device may be any fixing device that performs fixing by heating, pressurization, or light. When the electrophotographic toner of this embodiment is used as a light fixing toner, an optical fixing device (flash fixing device) is used. In other cases, a hot roll fixing device, an oven fixing device, or the like is preferably used.

  As the heat roll fixing device, a heating roll type fixing device is generally used in which a pair of fixing rolls are pressed against each other. As a pair of fixing rolls, a heating roll and a pressure roll are provided facing each other, and a nip is formed by pressure contact. The heating roll has a metal hollow core with a heater lamp inside, and a surface layer made of an oil- and heat-resistant elastic body layer (elastic layer) and a fluororesin, etc. are sequentially formed. Accordingly, an oil- and heat-resistant elastic body layer and a surface layer are sequentially formed on a metal hollow core metal core having a heater lamp inside. An unfixed toner image is fixed by passing a recording medium on which an unfixed toner image is formed through a nip region formed by the heating roll and the pressure roll.

On the other hand, the light source used in the optical fixing device includes a normal halogen lamp, a mercury lamp, a flash lamp, an infrared laser, and the like. It is desirable emission energy of the flash lamp is in the range of 1.0 J / cm ² to 7.0J / cm ^2, and more desirably in the range of 2J / cm ² to 5 J / cm ^2.

Here, the emission energy per unit area of flash light indicating the lamp intensity of xenon is expressed by the following equation.
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 flash lamp (usually the maximum paper width, cm), and S represents the energy density (J / cm ² ).

The light fixing method is preferably 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 ms to 100 ms, light is emitted, and the same portion is illuminated a plurality of times. As a result, since the light energy is not supplied to the toner image but supplied in a single light emission, the fixing condition is mild, and both void resistance and fixing property are realized.
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 present embodiment, the number of flash lamps is preferably in the range of 1 to 20, more preferably in the range of 2 to 10. The time difference between the plurality of flash lamps is preferably in the range of 0.1 msec to 20 msec, and more preferably in the range of 1 msec to 3 msec.
Furthermore, once emission energy of light emitted in one flash lamp is preferably a 0.1 J / cm ² or more 1 J / cm ² or less in the range, 0.4 J / cm ² or more 0.8 J / cm ² or less It is more preferable that it is in the range.

  In the present embodiment, the rotation direction of the latent image holding member (electrophotographic photosensitive member) and the developer holding member (the holding member that supplies the developer of the developing means to the latent image holding member) may be the same direction. . In this method, the amount of toner supplied to the development nip is increased. And in this embodiment, even if it is this system, carrier scattering is suppressed.

  Further, the process speed (recording medium conveyance speed) is 700 mm / sec or more, more desirably 1000 mm / s or more, and further desirably 1200 mm / sec or more. And in this embodiment, even if it is the said process speed, carrier scattering is suppressed.

  Hereinafter, although an example of the image forming apparatus of this embodiment is shown, it is not necessarily limited to this. In addition, the main part shown to a figure is demonstrated and the description is abbreviate | omitted about others.

  FIG. 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to the present embodiment. The image forming apparatus shown in FIG. 1 is one that forms a toner image with toner obtained by adding black to three colors of cyan, magenta, and yellow. The process speed (recording medium conveyance speed) in this image forming apparatus is also set to 700 mm / second or more.

  The image forming apparatus shown in FIG. 1 feeds the recording medium P wound in a roll shape by a paper feed roller 328, and on the one side of the recording medium P fed in this way, the recording medium P is fed upstream in the feeding direction. Four image forming units 312 (black (K), yellow (Y), magenta (M), cyan (C)) are provided in parallel from the side toward the downstream side. A light fixing type fixing device 326 is provided on the downstream side.

The black image forming unit 312K is a known electrophotographic image forming unit. Specifically, a charging unit 316K, an exposure unit 318K, a developing unit 320K, and a cleaner 322K are provided around the photosensitive member 314K, and a transfer unit 324K is provided via the recording medium P. The same applies to the other yellow, magenta, and cyan image forming units 312Y, 312M, and 312C.
When used for monochrome printing, only black (K) may be provided as the image forming unit 312.

  In the image forming apparatus shown in FIG. 1, toner images are sequentially transferred by the known electrophotographic method by the respective image forming units 312 </ b> K, 312 </ b> Y, 312 </ b> M, and 312 </ b> C onto the recording medium P drawn from the roll state. The image is fixed by the fixing device 326 to form an image.

  The light source as the light fixing means has the strongest light emission peak depending on the type, and the optimum light absorption characteristics in the near-infrared region required corresponding to this are also different. However, the adjustment of the light absorption characteristic in the near infrared region is easily performed by controlling the molecular structure.

  Next, an image forming apparatus according to another embodiment will be described. FIG. 2 is a schematic configuration diagram illustrating an example of an image forming apparatus according to another embodiment.

  The image forming apparatus shown in FIG. 2 is a quadruple tandem full-color image forming apparatus. The image forming apparatus shown in FIG. 2 is a first to first electrophotographic method that outputs yellow (Y), magenta (M), cyan (C), and black (K) images based on color-separated image data. Fourth image forming units 10Y, 10M, 10C, and 10K (image forming means) are provided. These image forming units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are juxtaposed at a predetermined distance in the horizontal direction. The units 10Y, 10M, 10C, and 10K may be process cartridges that are detachable from the main body of the image forming apparatus.

Above each of the units 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 as an intermediate transfer member is extended through each unit. The intermediate transfer belt 20 is provided by being wound around a driving roller 22 and a support roller 24 that are in contact with the inner surface of the intermediate transfer belt 20 that are spaced apart from each other from the left to the right in the drawing. It is designed to travel in the direction toward 10K. The support roller 24 is urged away from the drive roller 22 by a spring or the like (not shown), and a predetermined tension is applied to the intermediate transfer belt 20 wound around the support roller 24. Further, an intermediate transfer member cleaning device 30 is provided on the side of the image carrier of the intermediate transfer belt 20 so as to face the driving roller 22.
Further, each of the developing devices (developing means) 4Y, 4M, 4C, and 4K of the units 10Y, 10M, 10C, and 10K includes yellow, magenta, cyan, and black contained in the toner cartridges 8Y, 8M, 8C, and 8K. The four colors of toner are supplied.

  Since the first to fourth units 10Y, 10M, 10C, and 10K described above have the same configuration, here, the first unit that forms a yellow image disposed on the upstream side in the intermediate transfer belt traveling direction. 10Y will be described as a representative. Note that the second to fourth units are denoted by reference numerals with magenta (M), cyan (C), and black (K) instead of yellow (Y) in the same parts as the first unit 10Y. Description of 10M, 10C, 10K is omitted.

The first unit 10Y has a photoreceptor 1Y that functions as an image holding member. Around the photoreceptor 1Y, an electrostatic charge image is formed by exposing the surface of the photoreceptor 1Y to a predetermined potential with a charging roller 2Y and the charged surface with a laser beam 3Y based on the color-separated image signal. An exposure device 3; a developing device (developing means) 4Y for supplying the charged toner to the electrostatic image and developing the electrostatic image; a primary transfer roller 5Y (primary) for transferring the developed toner image onto the intermediate transfer belt 20; A transfer unit) and a photoconductor cleaning device (cleaning unit) 6Y for removing toner remaining on the surface of the photoconductor 1Y after the primary transfer with a cleaning blade.
The primary transfer roller 5Y is disposed inside the intermediate transfer belt 20, and is provided at a position facing the photoreceptor 1Y. Further, a bias power source (not shown) for applying a primary transfer bias is connected to each of the primary transfer rollers 5Y, 5M, 5C, and 5K. Each bias power source varies the transfer bias applied to each primary transfer roller under the control of a control unit (not shown).

Hereinafter, an operation of forming a yellow image in the first unit 10Y will be described. First, prior to the operation, the surface of the photoreceptor 1Y is charged to a potential of about −600V to −800V by the charging roller 2Y.
The photoreceptor 1Y is formed by laminating a photosensitive layer on a conductive substrate. This photosensitive layer usually has a high resistance (a resistance equivalent to that of a general resin), but has a property that the specific resistance of the portion irradiated with the laser beam changes when irradiated with the laser beam 3Y. Therefore, a laser beam 3Y is output to the surface of the charged photoreceptor 1Y via the exposure device 3 in accordance with yellow image data sent from a control unit (not shown). The laser beam 3Y is applied to the photosensitive layer on the surface of the photoreceptor 1Y, whereby an electrostatic charge image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic charge image is an image formed on the surface of the photoreceptor 1Y by charging, and the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3Y, and the charged charge on the surface of the photoreceptor 1Y flows. On the other hand, this is a so-called negative latent image formed by the charge remaining in the portion not irradiated with the laser beam 3Y.
The electrostatic image formed on the photoreceptor 1Y in this way is rotated to a predetermined development position as the photoreceptor 1Y travels. At this development position, the electrostatic charge image on the photoreceptor 1Y is visualized (developed image) by the developing device 4Y.

  For example, yellow toner is accommodated in the developing device 4Y. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y, and has a charge of the same polarity (negative polarity) as the charged charge on the photoreceptor 1Y, and a developer roll (developer holder). Is held on. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner is electrostatically attached to the latent image portion on the surface of the photoreceptor 1Y, and the latent image is developed with the yellow toner. . The photoreceptor 1Y on which the yellow toner image is formed continues to run at a predetermined speed, and the toner image developed on the photoreceptor 1Y is conveyed to a predetermined primary transfer position.

When the yellow toner image on the photoreceptor 1Y is conveyed to the primary transfer, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, and the electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y generates a toner image. The toner image on the photoreceptor 1 </ b> Y is transferred onto the intermediate transfer belt 20. The transfer bias applied at this time is a (+) polarity opposite to the polarity (−) of the toner, and is controlled to about +10 μA by the control unit (not shown) in the first unit 10Y, for example.
On the other hand, the toner remaining on the photoreceptor 1Y is removed and collected by the cleaning device 6Y.

Further, the primary transfer bias applied to the primary transfer rollers 5M, 5C, and 5K after the second unit 10M is also controlled according to the first unit.
Thus, the intermediate transfer belt 20 onto which the yellow toner image has been transferred by the first unit 10Y is sequentially conveyed through the second to fourth units 10M, 10C, and 10K, and the toner images of the respective colors are superimposed and transferred in a multiple manner.

  The intermediate transfer belt 20 onto which the four color toner images have been transferred through the first to fourth units is arranged on the image transfer surface side of the intermediate transfer belt 20 and the support roller 24 in contact with the inner surface of the intermediate transfer belt 20. The secondary transfer roller (secondary transfer means) 26 is connected to a secondary transfer portion. On the other hand, the recording medium P is fed at a predetermined timing into a gap where the secondary transfer roller 26 and the intermediate transfer belt 20 are pressed against each other via a supply mechanism, and a predetermined secondary transfer bias is applied to the support roller 24. The The transfer bias applied at this time is a (−) polarity that is the same polarity as the polarity (−) of the toner, and an electrostatic force from the intermediate transfer belt 20 toward the recording medium P is applied to the toner image, so The toner image is transferred onto the recording medium P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) for detecting the resistance of the secondary transfer portion, and is voltage-controlled.

Thereafter, the recording medium P is sent to a fixing device (fixing means) 28, the toner image is heated, and the color-superposed toner image is melted and fixed on the recording medium P. The recording medium P on which the color image has been fixed is unloaded to the discharge unit, and a series of color image forming operations is completed.
The image forming apparatus exemplified above is configured to transfer the toner image to the recording medium P via the intermediate transfer belt 20, but is not limited to this configuration, and the toner image is directly transferred from the photoconductor. It may be a structure that is transferred to a recording sheet.

[Process cartridge]
FIG. 3 is a schematic configuration diagram illustrating an example of a process cartridge according to the present embodiment. The process cartridge shown in FIG. 3 includes a unit including a photoconductor 107, a charging roller 108, a developing device 111, and a photoconductor cleaning device (cleaning means) 113, an opening 118 for exposure, and a discharge exposure. It is combined with and integrated with a housing 119 provided with an opening 117 and a mounting rail 116.
The process cartridge is detachable from the main body of the image forming apparatus including the transfer device 112, the fixing device 115, and other components not shown, and forms an image together with the main body of the image forming apparatus. It constitutes a device. P is a recording medium.

  The process cartridge shown in FIG. 3 includes a photoconductor 107, a charging device 108, a developing device 111, and a cleaning device (cleaning means) 113. These devices are selectively combined. Specifically, for example, in the process cartridge of the present embodiment, in addition to the developing device 111, at least one selected from the group consisting of the photosensitive member 107, the charging device 108, and the cleaning device (cleaning means) 113 is used. Prepare.

[Developer cartridge]
Next, the developer cartridge of this embodiment will be described. The developer cartridge according to the present embodiment is detachable from the image forming apparatus, and stores at least a developer to be supplied to a developing unit provided in the image forming apparatus. The developer according to the above embodiment is applied as the developer.

  The image forming apparatus shown in FIG. 2 is an image forming apparatus having a configuration in which the toner cartridges 8Y, 8M, 8C, and 8K are attached and detached. The developing devices 4Y, 4M, 4C, and 4K each have their respective developing devices (colors). ) And a developer cartridge corresponding to the above (not shown). When the amount of toner stored in the toner cartridge is low, the developer cartridge is replaced.

Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. Unless otherwise specified, “part” means “part by weight”.

(Career)
(Preparation of carrier A)
Fe ₂ O ₃ (64 mol%) and MnO (36 mol%) were wet-mixed with a ball mill, dried and pulverized, then calcined at 900 ° C. for 1 hour, and pulverized to about 0.1 mm to 1.5 mm. Further, wet pulverization with a ball mill for 24 hours, adding 0.8% by weight of polyvinyl alcohol as a binder to the total amount of Fe ₂ O ₃ and MnO, granulating spherical particles by a spray dryer method, and at 1280 ° C. in a nitrogen atmosphere The core material was obtained by baking and classifying after crushing.
100 parts of the obtained core material was coated with dimethyl silicone resin (manufactured by Dow Corning Toray; SR2410) to a solid content of 1.5 parts, and carrier A was obtained.

(Preparation of carrier B)
Carrier B was obtained in the same manner as Carrier A except that Fe ₂ O ₃ (57 mol%) and MnO (43 mol%) were used.

(Preparation of carrier C)
Carrier C was obtained in the same manner as Carrier A except that Fe ₂ O ₃ (80 mol%) and MnO (20 mol%) were used.

(Preparation of carrier D)
Carrier D was obtained in the same manner as Carrier A except that Fe ₂ O ₃ (51 mol%) and MnO (49 mol%) were used.

(Preparation of carrier E)
Carrier E was obtained in the same manner as Carrier A except that polyvinyl alcohol was changed to 0.6% by weight.

(Preparation of carrier F)
Carrier F was obtained in the same manner as Carrier A except that polyvinyl alcohol was changed to 1.0% by weight.
(Preparation of carrier G)
Carrier B was obtained in the same manner as carrier A except that Fe ₂ O ₃ (65 mol%) and CaO (35 mol%) were used.

  Table 1 below shows the volume average particle diameter and saturation magnetization of carriers A to G.

(Production of toner)
-Production of toner particles-
Polyester resin: 87 parts (Bisphenol A propylene oxide adduct / bisphenol A ethylene oxide adduct / polyester resin mainly composed of terephthalic acid / fumaric acid / trimellitic acid: Tg = 63 ° C., weight average molecular weight: 39000)
・ Carbon black (Mitsubishi Chemical Corporation: Brand name # 25): 8 parts
Polyethylene wax (Mitsui Chemicals, trade name 400P, weight average molecular weight 4000): 3 parts Positive charge controller (Nigrosine dye: Orient Chemicals, trade name Bontron N-04): 2 parts

  The above composition is powder-mixed with a Henschel mixer, heat-kneaded with a biaxial extruder (set temperature 105 ° C.), cooled, coarsely pulverized with a hammer mill, finely pulverized with a jet mill, and classified with an airflow classifier. Thus, toner particles having a volume average particle diameter D50 of 8.8 μm were obtained.

-Preparation of toner-
To 100 parts of the obtained toner particles, 0.8 part of hydrophobic silica particles (TG-820F; manufactured by Cabot Specialty Chemicals Inc.) and crosslinked resin particles MP1451 (volume average particle diameter) as a spherical external additive : 150 nm, shape factor SF1 = 115, 0.25 part by Soken Chemical Co., Ltd., and Milleke E-10 (volume average particle size: 0.65 μm, shape factor SF1 = 150, Mitsui Kinzoku Co., Ltd.) 0.15 part (manufactured by company) was externally mixed with a Henschel mixer to obtain toner a.

  Then, according to the following Tables 2 to 4, toners b to m were obtained in the same manner as the toner a, except that the types and addition amounts of the spherical external additive and the amorphous external additive were changed.

In the above table, the irregular resin particles A, B, and C are prepared as follows.
-Preparation of amorphous resin particle A-
370 parts of styrene, 30 parts of n-butyl acrylate, 8 parts of acrylic acid, 24 parts of dodecanethiol and 4 parts of carbon tetrabromide were mixed and dissolved in a nonionic surfactant (Nonipol 400: Sanyo Chemical Co., Ltd.) 6 parts) and 10 parts of an anionic surfactant (Neogen SC: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) were dissolved in 550 parts of ion-exchanged water and subjected to emulsion polymerization. 50 parts of ion-exchanged water in which 4 parts of ammonium persulfate was dissolved was added. After carrying out nitrogen substitution, the inside of the flask was stirred and heated in an oil bath until the contents reached 70 ° C., and emulsion polymerization was continued for 5 hours. As a result, a resin particle dispersion in which resin particles of 150 nm, Tg = 58 ° C., and weight average molecular weight Mw = 11500 were dispersed was obtained. The solid content concentration of this dispersion was 40% by weight.

  To 260 parts of the resin particle dispersion, 1.8 parts of polyaluminum chloride (PAC100W: manufactured by Asada Chemical Co., Ltd.) is added, 900 parts of ion-exchanged water is further added, and UltraTurrax T50 (IKA Co., Ltd.) is used in a round stainless steel flask. The mixture was mixed and dispersed using a product, and then stirred up to 40 ° C. while stirring the inside of the flask in an oil bath for heating. Then, after hold | maintaining for 30 minutes, it was 3.0 micrometers when the particle size was measured. Thereafter, 0.1N sodium hydroxide was added to the dispersion to adjust the pH of the system to 7, and then the mixture was heated to 80 ° C. and kept for 30 minutes while stirring was continued. After cooling, the volume average particle diameter was measured to be 3.2 μm. The resin particles were separated by filtration, washed four times with ion exchange water, and then dried to obtain amorphous resin particles. The value of the shape factor SF1 of the irregular resin particles was 135.

-Preparation of amorphous resin particle B-
After adding sodium hydroxide, the pH of the system was adjusted to 7, and then heated to 85 ° C. and held for 45 minutes, and the same operation as in the amorphous resin particles A was performed to obtain amorphous resin particles B. The volume-average particle diameter of the irregular resin particles B was 3.1 μm, and the shape factor SF1 was 128.

-Production of amorphous resin particles C-
After adding sodium hydroxide, the pH of the system was adjusted to 7.2, and then heated to 75 ° C. and maintained for 20 minutes to perform the same operation as that for the amorphous resin particles A to obtain amorphous resin particles C. It was. The volume average particle diameter of the irregular resin particles C was 3.5 μm, and the shape factor SF1 was 190.

(Examples 1 to 11 and Comparative Examples 1 to 5)
In a combination according to the following Table 5, the carrier and the toner were put into a V-type blender and mixed at 40 rpm for 20 minutes to obtain developers A to P. These were used as developers of the respective examples and comparative examples.

[Evaluation 1]
For the developers A to P, a DocuPrint 1100 CF remodeling machine manufactured by Fuji Xerox Co., Ltd. (process speed 1000 mm / sec, the rotation direction of the latent image holding body and the developer holding body is the same direction, and the latent image holding body and the developer. In the developing nip portion where the holding body is opposed, the evaluation was performed by an against system in which the vectors in the tangential directions of the two are opposite to each other. Evaluation was conducted at a temperature of 20 ° C. and 50% RH, and a chart of 5% image density including a halftone image, a photographic image and a solid image was printed on Fuji Xerox Co., Ltd. fine plain paper (E) A2 roll 200 m. The output was processed into a 000 m roll. Evaluation was performed with respect to density unevenness, image quality (brush mark), contamination in the developing machine and apparatus, and change in developer amount at the initial stage and when A4: 1,000,000 sheets were printed. The output is performed on roll paper whose width is the length of the long side of A4 paper, and when the length of one short side (210 mm) of A4 paper is printed, A4 is equivalent to 1 sheet. It was time. The evaluation results are shown in Table 6.

-Density unevenness-
The density of five solid image portions within the A4 area was measured using X-RITE 404, and the maximum / minimum difference was evaluated as density unevenness. Evaluation was performed according to the following criteria, and ◎ and ○ were acceptable, but Δ and × were unacceptable levels.
A: Maximum-minimum <0.10
○: 0.1 ≦ maximum−minimum <0.15
Δ: 0.15 ≦ maximum−minimum <0.20
×: 0.20 ≦ maximum−minimum

-Brush mark-
As in the case of density unevenness, the occurrence of brush marks was visually confirmed on the solid image portion, and evaluation was performed according to the following criteria.
A: The brush mark cannot be confirmed.
○: Level where there is a slight brush mark occurrence but no problem in image quality △: Level where brush mark is generated but is acceptable ×: Level where brush mark is generated and is unacceptable in image quality

-Fouling in developing machine and equipment-
Initially and after printing, the inside of the machine was visually observed and evaluated according to the following criteria.
◎: Level where dirt inside the machine cannot be confirmed visually ○: Slightly spotted dirt inside the machine is observed, but it is almost inconspicuous and acceptable level △: dirt inside the machine is noticeable and visually unacceptable level X: The dirt inside the machine is very noticeable by visual observation, and the level of dirt is unacceptable.

-Change in developer amount-
The change in the developer amount after 1,000,000 sheets was measured with respect to the input developer amount (4 kg) and evaluated according to the following criteria.
◎: 3.8 kg ≦ developer amount ≦ 4.0 kg ... there is almost no phenomenon of the developer amount, and there is no problem. ○: 3.7 kg ≦ developer amount <3.8 kg ... Although there is a slight decrease, Level where there is no practical problem Δ: 3.6 kg ≦ developer amount <3.7 kg... Level that requires replenishment, unacceptable level ×: developer amount <3.6 kg Problems with insufficient amount of developer on the body.

  From the results of the evaluation 1, it can be seen that the present example gives superior results with respect to the brush mark, density unevenness, stains in the developing machine and apparatus, and changes in the developer amount, as compared with the comparative example.

[Evaluation 2]
Evaluation was performed in the same manner as in Evaluation 1 except that the DocuPrint 1100 CF modified machine manufactured by Fuji Xerox Co., Ltd. was changed to a process speed of 600 mm / sec. The results are shown in Table 7.

  From the results of Evaluation 1 together with Evaluation 2 above, the present embodiment is more sensitive to brush marks, density unevenness, contamination in the developing machine and apparatus, and changes in developer amount, especially when the process speed is increased, as compared to the comparative example. It can be seen that excellent results are obtained.

[Evaluation 3]
The DocuPrint 1100 CF remodeling machine manufactured by Fuji Xerox Co., Ltd. has a tangent line between the latent image holding member and the developer holding member at the developing nip where the rotation directions of the latent image holding member and the developer holding member are opposite to each other. Evaluation was performed in the same manner as in Evaluation 1 except that the direction vector was changed to the With method in which the direction vector was the same. The results are shown in Table 8.

  From the results of evaluation 1 together with the above evaluation 3, the present embodiment is particularly effective when compared with the comparative example, even when the rotation method of the latent image holding body and the developer holding body is the same direction. It can be seen that excellent results are obtained with respect to density unevenness, contamination in the developing machine and apparatus, and change in the developer amount.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an exemplary embodiment. It is a schematic block diagram shown about an example of the image forming apparatus which concerns on other embodiment. It is a schematic block diagram which shows an example of the process cartridge which concerns on this embodiment.

Explanation of symbols

1Y, 1M, 1C, 1K Photoconductor 2Y, 2M, 2C, 2K Charging roller 3Y, 3M, 3C, 3K Laser beam 3 Exposure device 4Y, 4M, 4C, 4K Developing device 5Y, 5M, 5C, 5K Primary transfer Rollers 6Y, 6M, 6C, 6K Cleaning devices 8Y, 8M, 8C, 7K Toner cartridges 10Y, 10M, 10C, 10K Image forming unit 20 Intermediate transfer belt 22 Drive roller 24 Support roller 26 Secondary transfer roller 28 Fixing device 30 Intermediate transfer Body cleaning device 107 Photoconductor 108 Charging roller 108 Charging device 111 Developing device 112 Transfer device 115 Fixing device 116 Mounting rail 117 Opening portion 118 Opening portion 119 Housings 312Y, 312M, 312C, 312K Image forming units 314Y, 34M, 314C, 314K, 314K photoreceptor 3 6Y, 316M, 316C, 316K, 316K Charger 318Y, 318M, 318C, 318K, 318K Exposure means 320Y, 320M, 320C, 320K, 320K Developer 322Y, 322M, 322C, 322K, 322K Cleaner 324Y, 324M, 324C, 324K 324K Transfer device 326 Fixing device 328 Paper feed roller

Claims (12)

A toner containing toner particles, a spherical external additive having a volume average particle diameter of 80 nm to 200 nm, and an amorphous external additive;
A carrier having a volume average particle diameter of 45 μm or more and 75 μm or less and a saturation magnetization of 70 A · m ² / kg or more and 95 A · m ² / kg or less;
A developer for developing an electrostatic charge.   The developer for electrostatic charge development according to claim 1, wherein the addition amount of the spherical external additive to the toner particles is larger than the addition amount of the amorphous external additive to the toner particles.   2. The static electricity according to claim 1, wherein a ratio of an addition amount of the spherical external additive to the toner particles and an addition amount of the amorphous external additive to the toner particles is 100: 5 to 100: 90. Developer for charge development.   The developer for electrostatic charge development according to claim 1, wherein an addition amount of the spherical external additive to the toner particles is 0.01% by mass or more and 10.00% by mass or less.   The developer for electrostatic charge development according to claim 1, wherein an amount of the amorphous external additive added to the toner particles is 0.02% by mass or more and 10.00% by mass or less.   The electrostatic charge developing developer according to claim 1, wherein the amorphous external additive has a shape factor SF1 of 135 or more and 190 or less.   2. The developer for electrostatic charge development according to claim 1, wherein a difference in shape factor SF <b> 1 between the spherical external additive and the amorphous external additive is 15 or more and 70 or less. Contains a developer that is detached from the image forming apparatus and supplied to at least developing means provided in the image forming apparatus;
A developer cartridge for developing an electrostatic charge image, wherein the developer is the developer for developing an electrostatic charge image according to any one of claims 1 to 7. A developer for developing an electrostatic charge image according to any one of claims 1 to 7, wherein the developer for developing an electrostatic charge image is formed on an electrostatic latent image formed on the surface of the electrostatic latent image holding member. Developing means for developing the toner image by:
At least one selected from the group consisting of an electrostatic latent image holding body, a charging means for charging the electrostatic latent image holding body, and a toner removing means for removing toner remaining on the surface of the electrostatic latent image holding body And comprising
A process cartridge that is detachable from the main body of the image forming apparatus. An electrostatic latent image carrier;
Charging means for charging the surface of the electrostatic latent image holding member;
Electrostatic latent image forming means for forming an electrostatic latent image on the surface of the electrostatic latent image holding member;
A developing means for developing the electrostatic latent image into a toner image with a developer, the developer holding body disposed opposite to the electrostatic latent image holding body;
Transfer means for transferring the toner image formed on the surface of the electrostatic latent image holding member to the surface of a recording medium;
Fixing means for fixing the toner image transferred to the recording medium;
With
An image forming apparatus, wherein the developer is the developer for developing an electrostatic image according to any one of claims 1 to 7.   The image forming apparatus according to claim 10, wherein the latent image holder and the developer holder are rotated in the same direction.   The image forming apparatus according to claim 10, wherein a process speed is 700 mm / sec or more.

Images