JP2017167387A - Carrier for electrostatic latent image developer, two-component developer using the same, developer for replenishment, toner storage unit, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier for an electrostatic latent image development that enables sufficient charge control over image quality required in the field of production printing, and is used for a two-component developer used for electrophotography and electrostatic recording method that enable high durability.SOLUTION: There is provided a carrier for an electrostatic latent image developer including a core material particle and a resin layer that covers the core material particle, where the resin layer contains magnesium oxide fine particles, and the amount of Mg exposed on the surface of the carrier is 3.0 to 15.0 atomic%.SELECTED DRAWING: None

Description

  The present invention relates to a carrier for developing an electrostatic latent image, a two-component developer using the carrier, a developer for supply, a toner containing unit, and an image forming apparatus.

  In electrophotographic image formation, an electrostatic latent image is formed on an electrostatic latent image carrier such as a photoconductive substance, and a charged toner is attached to the electrostatic latent image to form a toner image. After that, the toner image is transferred to a recording medium and fixed to form an output image. In recent years, the technology of copying machines and printers using an electrophotographic system is rapidly expanding from monochrome to full color, and the full color market tends to expand.

The two-component developer used in the electrophotographic system is composed of a toner and a carrier, and the carrier is mixed and agitated with the toner separately supplied in the developing tank to give the toner a desired charge. It is a carrier material that carries toner bearing an electrostatic latent image on the photoreceptor to form a toner image.
Carriers include prevention of toner filming, formation of a uniform surface, prevention of surface oxidation, prevention of moisture sensitivity deterioration, extension of developer life, prevention of adhesion to the surface of the photoreceptor, For the purpose of protecting from scratches or abrasion, controlling the charge polarity, adjusting the charge amount, etc., a coating layer in which a resin containing carbon black is formed on the surface is known. However, the carrier can initially form a good image, but as the number of copies increases, the coating layer is scraped, and the characteristics that greatly affect the image quality, such as carrier resistance and chargeability, vary. As a result, there is a problem that the image quality deteriorates. Further, there is a problem that color stains occur due to the coating layer being scraped or the carbon black being detached from the coating layer.

  As a method for solving the above problem, for example, Patent Document 1 discloses a carrier in which a coating layer containing antimony-doped tin oxide (ATO) is formed as acicular conductive powder. Patent Document 2 discloses a carrier in which a coating layer containing conductive particles in which a tin dioxide layer and an indium oxide layer containing tin dioxide are laminated on the surface of base particles is formed. Patent Document 3 includes first conductive particles having carbon on the surface of tin oxide particles, and second conductive particles in which the surfaces of metal oxide particles and / or metal salt particles are subjected to conductive treatment. A carrier having a coating layer comprising is disclosed.

  Further, Patent Document 4 and Patent Document 5 disclose carriers in which the coating film contains barium sulfate and the Ba / Si ratio with respect to all elements measured by XPS is 0.01 to 0.08. The present invention is effective for reducing the charging ability of the carrier when the toner is balanced in a larger image area. Patent Document 6 discloses magnesium hydroxide or magnesium oxide in which carbon black or zinc oxide is used as conductive particles, and the shape control (SF-1) has a variation rate of 16% or less as charge control particles. Is disclosed.

  However, in recent years, the toner tends to be fixed at a low temperature to reduce power consumption, and in addition to the increase in printing speed, toner spent on the carrier is more likely to occur. In addition, toners tend to contain many additives due to demands for higher image quality, and these are spent on the carrier, resulting in a decrease in toner charge amount, a margin for toner scattering and background contamination. Currently. When the charge control fine particles are incorporated by a method of forming a resin layer on the ferrite core surface layer by the action of mechanical impact force as described in Patent Document 6, large fine particles are broken by the action of mechanical impact force. Therefore, only charge control fine particles having a small particle diameter can be present in the resin layer, and in the use environment required for the recent electrophotography as described above, the fine particles are covered with the toner spent, which is sufficiently effective. Cannot be used. With respect to such new problems, the carriers as described in Patent Documents 1 to 6 have not been able to exhibit sufficient effects.

  On the other hand, in the field of production printing, where the market has been expanding in recent years, higher image quality than ever has been demanded. It is technically very difficult to deal with density fluctuations and density irregularities within one image, density fluctuations between images when printing tens of thousands of sheets, and the like only with the machine body. For this reason, it is more demanded than ever to control the toner charge amount to a constant level, and the conventional carrier as described above cannot satisfy the required characteristics.

  The present invention is based on the above technical problem and can be used in an electrophotographic method and an electrostatic recording method capable of sufficient charge control for image quality required in the field of production printing and enabling high durability. An object of the present invention is to provide a carrier for developing an electrostatic latent image used for a two-component developer.

  The inventors of the present invention are required in the field of production printing by incorporating fine particles of magnesium oxide in a resin layer of a carrier for an electrostatic latent image developer and using a carrier having a specific range of Mg exposure on the carrier surface. The present inventors have found that sufficient charge control can be performed with respect to image quality and have reached the present invention.

Thus, the above problem is solved by the following (1) of the present invention.
(1) A carrier for an electrostatic latent image developer having core material particles and a resin layer covering the core material particles, wherein the resin layer contains magnesium oxide fine particles, and the Mg exposure amount on the carrier surface is 3 A carrier for an electrostatic latent image developer, characterized by being from 0 to 15.0 [atomic%].

  By using the electrostatic latent image developer carrier of the present invention, sufficient charge control can be performed for image quality required in the field of production printing, and high durability can be achieved.

It is a figure which shows an example of the image forming apparatus of this invention. It is a figure which shows an example of the process cartridge of this invention. (A) represents a normal image in a vertical band chart, and (B) is a diagram showing a ghost image as a problem.

The carrier for an electrostatic latent image developer of the present invention will be described in detail.
Although the present invention relates to the following (1), the following (2) to 8) are also included in the embodiment of the present invention, and these will be described together.
(1) A carrier for an electrostatic latent image developer having core material particles and a resin layer covering the core material particles, wherein the resin layer contains magnesium oxide fine particles, and the Mg exposure amount on the carrier surface is 3 A carrier for an electrostatic latent image developer, characterized by being from 0 to 15.0 [atomic%].
(2) The carrier for an electrostatic latent image developer according to (1) above, wherein an average particle diameter D in the carrier cross-sectional image of the magnesium oxide fine particles is 500 to 1500 [nm].
(3) The resin of the resin layer contains a crosslinked product of a copolymer containing a structural unit represented by the following general formula (A) and a structural unit represented by the general formula (B). The carrier for an electrostatic latent image developer according to (1) or (2).
(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom or methyl group m: integer of 1 to 8 R ² : alkyl group having 1 to 4 carbon atoms R ³ : alkyl group having 1 to 8 carbon atoms, or alkoxy group having 1 to 4 carbon atoms X : 10 to 90 mol%
Y: 10 to 90 mol%
However, X and Y represent the composition ratio of the structural unit represented by the general formula (A) and the structural unit represented by the general formula (B) in the copolymer. )
(4) A two-component developer comprising the electrostatic latent image developer carrier and toner according to any one of (1) to (3).
(5) The two-component developer according to (4), wherein the toner is a color toner.
(6) A replenishment developer including a carrier and a toner, the toner containing 2 to 50 parts by mass of toner relative to 1 part by mass of the carrier, wherein the carrier is any one of (1) to (3). A developer for replenishment, which is a carrier for an electrostatic latent image developer.
(7) A developer containing unit comprising the two-component developer according to (4) or (5) or the supply developer according to (6).
(8) An electrostatic latent image carrier, charging means for charging the electrostatic latent image carrier, exposure means for forming an electrostatic latent image on the electrostatic latent image carrier, and the electrostatic latent image Development means for developing the electrostatic latent image formed on the carrier using the two-component developer described in (4) or (5) above to form a toner image, and the electrostatic latent image carrier An image forming apparatus comprising: transfer means for transferring a toner image formed thereon onto a recording medium; and fixing means for fixing the toner image transferred onto the recording medium.

  In the present invention, it is important that magnesium oxide fine particles are contained in the resin layer of the carrier, and a certain amount of Mg element is exposed on the carrier surface. Magnesium oxide is excellent in chargeability with negatively charged toner, and is used for the purpose of imparting excellent charging performance to the carrier from the initial stage to after long-term use.

(Charging performance imparting fine particles)
Magnesium oxide, which is a charging performance-imparting fine particle used in the present invention, is known to exhibit excellent charging ability particularly for negatively charged toner. The present inventors include magnesium oxide fine particles in the carrier coat resin layer and expose a certain amount of Mg element on the carrier surface, so that it is extremely excellent even in long-term use as required in the production printing field. It has been found that the charging stability can be maintained. It is important to keep the Mg exposure amount on the carrier surface within a certain range (3.0 to 15.0 [atomic%]) found by the present inventors. If the Mg exposure amount is less than 3.0 [atomic%], sufficient chargeability imparting ability cannot be obtained, and in particular, deterioration of the charge ability with time is caused. The decrease in charging ability causes quality problems such as background fogging and toner scattering. On the other hand, if the Mg exposure amount is more than 15.0 [atomic%], the charge imparting particles that are exposed excessively on the surface become a starting point for the toner and its external additives to adhere, and toner spent is likely to occur. As a result, the charging ability deteriorates over time.

  The amount of Mg exposed on the carrier surface was measured by AXIS / ULYRA (Shimadzu / Kratos). The beam irradiation area is approximately 900 μm × 600 μm, and a range of 25 carriers × 17 is detected. The penetration depth is 0 to 10 nm, and information near the carrier surface is detected. The specific measurement method was carried out in the measurement mode: Electrostatic, excitation source: monochrome (Al), detection method: spectrum mode, and magnet lens: OFF. First, a detection element was specified by a wide-area scan, and then a peak was detected by a narrow scan for each detection element. Thereafter, atomic% of Mg with respect to all the detected elements was calculated with the attached peak analysis software.

  The charging performance-imparting fine particles of the present invention preferably have an average particle diameter D in the range of 500 to 1500 [nm] in the carrier cross-sectional image. When the average particle diameter D is 500 [nm] or more, the particles are sufficiently exposed on the outermost surface of the carrier, and the effect of imparting chargeability targeted in the present invention is sufficiently exhibited. On the other hand, when the average particle size is 1500 [nm] or less, the particles are not excessively large, so that separation from the resin layer hardly occurs.

  The average particle diameter D of the charging performance imparting fine particles in the carrier cross-sectional image is measured by the following method. The carrier is mixed in an embedding resin (Devcon, two-component mixed, 30-minute curable epoxy resin), left to stand overnight or longer, and a rough cross-section sample is prepared by mechanical polishing. A cross section polisher (SM-09010 manufactured by JEOL) was used for this, and the cross-section was finished under the conditions of an acceleration voltage of 5.0 kV and a beam current of 120 μA. This is photographed under the conditions of an acceleration voltage of 0.8 kV and a magnification of 30000 times using a scanning electron microscope (Merlin manufactured by Carl Zeiss). The captured image is taken into a TIFF image, and the average particle size of magnesium oxide particles is calculated from 100 carrier particles using Image-Pro Plus manufactured by Media Cybernetics. As the particle diameter calculation method, the area of each particle was calculated, the diameter of a perfect circle corresponding to the area, that is, the equivalent circle diameter, was obtained, and the average value of 100 particles was defined as the average particle diameter D.

  Moreover, it is preferable to contain 50-300 mass parts charging performance imparting microparticles with respect to 100 mass parts of resin as the quantity of the charging performance imparting microparticles contained in the resin coating layer. If the amount of the charging performance imparting fine particles is 50 parts by mass or more, the particles are sufficiently exposed on the outermost surface of the carrier and have a sufficient effect of imparting charging properties. The ratio does not become relatively small, and it becomes difficult for the toner to spend on the carrier surface, and as a result, problems such as increased resistance are unlikely to occur.

(Conductive fine particles)
In combination with the above-mentioned charging performance-imparting fine particles, conductive fine particles may be contained in the carrier-coated resin layer for the purpose of controlling resistance and suppressing the abrasion of the resin layer when used for a long period of time. The conductive fine particles can be made of a filler such as aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, zirconium oxide, etc., formed of tin dioxide or indium oxide as a layer, carbon black, etc. Barium sulfate is preferred. Substrates such as aluminum oxide, titanium dioxide, zinc oxide, silicon dioxide, barium sulfate, and zirconium oxide can be used as the non-conductive filler.
The resin coating layer preferably contains 50 to 500 parts by mass of conductive fine particles with respect to 100 parts by mass of the resin. By containing a certain amount of conductive fine particles in the resin coating layer, it becomes possible to suppress the abrasion of the coating layer when used for a long time in a developing machine.

(Resin layer resin)
In the carrier of the present invention, the resin component in the resin layer is a monomer A component that is a structural unit represented by the following general formula (A), and a monomer B component that is a structural unit represented by the following general formula (B) Of a copolymer having a structural unit represented by the following general formula (A) and a structural unit represented by the general formula (B) (shown in the following [Structural Formula 1]) obtained by radical copolymerization. It is preferable to contain a crosslinked product. The carrier of the present invention is preferably a carrier obtained by hydrolyzing the copolymer to form a silanol group, and crosslinking and coating by condensation using a catalyst, followed by heat treatment.
Here, in the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.
R ¹ : hydrogen atom or methyl group m: represents an integer of 1 to 8, and (CH ₂ ) _m is a methylene group, ethylene group, propylene
Group, alkylene group such as butylene group R ² : methyl group having 1 to 4 carbon atoms, ethyl group, propyl group, isopropyl group,
And an alkyl group such as a butyl group R ³ : a methyl group having 1 to 8 carbon atoms, an ethyl group, a propyl group, an isopropyl group, and
An alkyl group such as a butyl group, or a methoxy group having 1 to 4 carbon atoms, an ethoxy group,
Alkoxy groups such as propoxy group and butoxy group X: 10 to 90 mol%
Y: 10 to 90 mol%
However, X and Y represent the composition ratio of the structural unit represented by the general formula (A) and the structural unit represented by the general formula (B) in the copolymer. )

In the structural unit represented by the general formula (A) (hereinafter also referred to as component A), X = 10 to 90 mol%, and more preferably 30 to 70 mol%.
The component A has an atomic group having a large number of alkyl groups in the side chain, tris (trialkylsiloxy) silane, and the surface energy decreases as the ratio of the component A increases with respect to the entire resin. Adhesion of components and wax components is reduced. When the A component is 10 mol% or more, a sufficient effect is obtained, and adhesion of the toner component is reduced. On the other hand, when the content is 90 mol% or less, the component B is not reduced, the crosslinking proceeds, the toughness is increased, the adhesion between the core material and the resin layer is improved, and the durability of the carrier film is improved.

R ² is an alkyl group having 1 to 4 carbon atoms. Examples of such a monomer component include a tris (trialkylsiloxy) silane compound represented by the following formula.
In the following formulae, Me is a methyl group, Et is an ethyl group, and Pr is a propyl group.
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiMe 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiPr 3) 3

  The production method of the component A is not particularly limited, but a method of reacting tris (trialkylsiloxy) silane with allyl acrylate or allyl methacrylate in the presence of a platinum catalyst, or a carboxylic acid described in JP-A-11-217389. It can be obtained by a method of reacting methacryloxyalkyltrialkoxysilane and hexaalkyldisiloxane in the presence of an acid and an acid catalyst.

The structural unit represented by the general formula (B) (hereinafter also referred to as B component) is a radically polymerizable bifunctional or trifunctional silane compound, and Y = 10 to 90 mol%. Preferably it is 30-70 mol%.
When the B component is 10 mol% or more, sufficient toughness can be obtained. On the other hand, when it is 90 mol% or less, the coating film does not become too hard and film scraping hardly occurs. Moreover, environmental characteristics are improved. If a large number of hydrolyzed crosslinking components remain as silanol groups, environmental characteristics (humidity dependence) may be deteriorated.
Examples of such component B include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyl. Examples include dimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (isopropoxy) silane, and 3-acryloxypropyltri (isopropoxy) silane.

In the copolymer of the present invention, an acrylic compound (monomer) serving as a structural unit represented by the following general formula (C) may be added as a C component to the A component and the B component. Examples of such a C component include a copolymer having a structural unit represented by the following [Structural Formula 2].
(In the formula, R ¹ , m, R ² , R ³ , R ⁴ , x, y, and z are as follows.)
R ¹ : hydrogen atom or methyl group m: integer of 1 to 8 R ² : alkyl group having 1 to 4 carbon atoms R ³ : alkyl group having 1 to 8 carbon atoms, or alkoxy group having 1 to 4 carbon atoms R ⁴ : an alkyl group having 1 to ⁴ carbon atoms or an alkyl group having 1 to ⁴ carbon atoms which may be substituted with an amino group x: 10 to 40 mol%
y: 10-40 mol%
z: 30 to 80 mol%)
However, x, y, z represents the composition ratio of the A component, the B component, and the C component in the copolymer, and 60 mol% <y + z <90 mol%. )

The component C imparts flexibility to the coating and improves the adhesion between the core material and the coating. Adequate adhesiveness is obtained when the C component is 30 mol% or more, and when it is 80 mol% or less, either the A component or the B component does not become 10 mol% or less. It becomes possible to make water-based, hardness and flexibility (film scraping) compatible.
As the acrylic compound (monomer) of component C, acrylic acid ester and methacrylic acid ester are preferable. Specifically, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, butyl methacrylate, butyl acrylate, 2- (dimethylamino) ) Ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, 3- (dimethylamino) propyl methacrylate, 3- (dimethylamino) propyl acrylate. Of these, alkyl methacrylate is preferable, and methyl methacrylate is particularly preferable. One of these compounds may be used alone, or a mixture of two or more may be used.

  Japanese Patent No. 3691115 is known as a technique for improving durability by crosslinking a coating. Japanese Patent No. 3691115 discloses radical copolymerization of a magnetic particle surface with an organopolysiloxane having at least a terminal vinyl group and at least one functional group selected from the group consisting of hydroxyl group, amino group, amide group and imide group. Is a carrier for developing an electrostatic image characterized in that a copolymer with a photopolymerizable monomer is coated with a thermosetting resin crosslinked with an isocyanate compound. The current situation is that it has not been obtained.

  The reason for this is not clear enough, but in the case of a thermosetting resin obtained by crosslinking the above-mentioned copolymer with an isocyanate compound, the isocyanate in the copolymer resin is understood from the structural formula. There are few functional groups per unit mass which react (crosslink) with a compound, and a two-dimensional or three-dimensional dense crosslinked structure cannot be formed at the crosslinking point. Therefore, if it is used for a long time, the film is easily peeled off or scraped off (the abrasion resistance of the film is small), and it is assumed that sufficient durability is not obtained. When the film is peeled off or scraped off, the image quality changes due to a decrease in carrier resistance and carrier adhesion occurs. Also, peeling or scraping of the coating reduces the fluidity of the developer and causes a decrease in the amount of pumping, which causes a decrease in image density, contamination when toner is increased, and toner scattering.

The resin is a copolymer resin having a large number of bifunctional or trifunctional crosslinkable functional groups (points) (2 to 3 times more per unit mass) than the resin unit mass. Furthermore, it is considered that the coating film is extremely tough and hard to be scraped, and is highly durable. Further, it is presumed that the aging stability of the coating is maintained because the crosslinking by the siloxane bond of the present invention has a higher binding energy and is more stable against heat stress than the crosslinking by the isocyanate compound.
The cross-linked product of the copolymer having the structure represented by [Structural Formula 1] or [Structural Formula 2] is preferably contained in a proportion of 5% by mass to 80% by mass with respect to the solid content of the resin layer. .

  As the carrier coating resin, a silicone resin, an acrylic resin, or a combination thereof can be used. This is because acrylic resin has a very excellent property of abrasion resistance due to its strong adhesiveness and low brittleness, but on the other hand, since the surface energy is high, the toner component spent in combination with easily spent toner Problems such as a decrease in charge amount due to accumulation may occur. In this case, this problem can be solved by using together a silicone resin that has an effect that it is difficult to spend the toner component due to the low surface energy and the accumulation of the spent component is difficult to progress due to film scraping. However, since the silicone resin has weak adhesiveness and high brittleness, it also has a weak point that it has poor wear resistance. Therefore, it is important to obtain a good balance between the properties of these two resins. It is possible to obtain a coating film having wear characteristics. Therefore, the improvement effect is remarkable. This is because the silicone resin has a low surface energy, so that it is difficult to spend the toner component, and it is difficult to accumulate the spent component due to film scraping.

  As used herein, the term “silicone resin” refers to all commonly known silicone resins, including straight silicone consisting of only organosilosan bonds, silicone resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. However, it is not limited to this. Examples of commercially available straight silicone resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicone. In this case, it is possible to use the silicone resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, modified silicone resins include KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicone. , SR2110 (alkyd modified) and the like.

  The acrylic resin referred to in this specification refers to all resins having an acrylic component, and is not particularly limited. In addition, it is possible to use the acrylic resin alone, but it is also possible to use at least one other component that undergoes a crosslinking reaction at the same time. Examples of other components that undergo a crosslinking reaction include amino resins and acidic catalysts, but are not limited thereto. The amino resin here refers to guanamine, melamine resin and the like, but is not limited thereto. Moreover, what has a catalytic action can be used with an acidic catalyst here. For example, it has a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type, but is not limited thereto.

The resin layer further preferably contains a cross-linked product of an acrylic resin and an amino resin.
Thereby, fusion | melting of resin layers can be suppressed, maintaining moderate elasticity.
The amino resin is not particularly limited, but a melamine resin and a benzoguanamine resin are preferable because the charge imparting ability of the carrier can be improved. In addition, when it is necessary to appropriately control the charge imparting ability of the carrier, another amino resin may be used in combination with the melamine resin and / or the benzoguanamine resin.
As the acrylic resin capable of crosslinking with the amino resin, those having a hydroxyl group and / or a carboxyl group are preferable, and those having a hydroxyl group are more preferable. Thereby, adhesiveness with core material particle | grains or electroconductive fine particles can further be improved, and the dispersion stability of electroconductive fine particles can also be improved. In this case, the acrylic resin preferably has a hydroxyl value of 10 mgKOH / g or more, and more preferably 20 mgKOH / g or more.

In the present invention, the resin layer composition preferably contains a silane coupling agent.
Thereby, electroconductive fine particles can be disperse | distributed stably.
The silane coupling agent is not particularly limited, but r- (2-aminoethyl) aminopropyltrimethoxysilane, r- (2-aminoethyl) aminopropylmethyldimethoxysilane, r-methacryloxypropyltrimethoxysilane, N -Β- (N-vinylbenzylaminoethyl) -r-aminopropyltrimethoxysilane hydrochloride, r-glycidoxypropyltrimethoxysilane, r-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, Vinyltriacetoxysilane, r-chloropropyltrimethoxysilane, hexamethyldisilazane, r-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium Chloride, r-chloropropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldiethoxysilane, 1, Examples include 3-divinyltetramethyldisilazane and methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, and two or more of them may be used in combination.
Examples of commercially available silane coupling agents include AY43-059, SR6020, SH6020, SZ6023, SH6026, SZ6032, SZ6050, AY43-310M, SZ6030, SH6040, AY43-036, AY43-031, sh6062, Z-6911, sz6300, sz6075, sz6079, sz6083, sz6070, sz6072, Z-6721, AY43-004, Z-6187, AY43-021, AY43-043, AY43-040, AY43-047, Z-6265, AY43-204M, AY43-048, Z-6403, AY43-206M, AY43-206E, Z6341, AY43-210MC, AY43-083, AY43-101, AY43-013, AY43-158E Z-6920, Z-6940 (Toray Ltd. Silicone Co., Ltd.) and the like.
It is preferable that the addition amount of a silane coupling agent is 0.1-10 mass% with respect to the said silicone resin. When the addition amount of the silane coupling agent is 0.1% by mass or more, the adhesion between the core material particles and conductive fine particles and the silicone resin is improved, and the resin layer does not fall off during long-term use. When the content is 10% by mass or less, toner filming does not occur during long-term use.

  As the polycondensation catalyst, a titanium-based catalyst, a tin-based catalyst, a zirconium-based catalyst, and an aluminum-based catalyst can be mentioned. In the present invention, among these various catalysts, among titanium-based catalysts that give excellent results, particularly titanium Isopropoxybis (ethyl acetoacetate) is most preferred as the catalyst. This is considered to be because the effect of promoting the condensation reaction of the silanol group is large and the catalyst is hardly deactivated.

In addition, a resin layer can be formed using the composition for resin layers containing magnesium oxide microparticles | fine-particles, the said copolymer, a catalyst, resin other than the said copolymer, and a solvent as needed.
Specifically, while coating the core particles with the resin layer composition, the copolymer may be hydrolyzed to form silanol groups and condensed to produce a crosslinked product. After coating the core particles with the resin layer composition, the copolymer may be hydrolyzed to form silanol groups and condensed to produce a crosslinked product. The method of condensing silanol groups while coating the core material particles with the resin layer composition is not particularly limited, but the method of coating the core particles with the resin layer composition while applying heat, light, etc. Etc. Further, the method for condensing the silanol group after coating the core material particles with the resin layer composition is not particularly limited, but there is a method in which the core material particles are coated with the resin layer composition and then heat-treated. Can be mentioned.
The heat treatment temperature during this heat treatment is preferably 100 to 350 ° C, more preferably 150 to 250 ° C.
In general, a resin having a high molecular weight has a very high viscosity, and when applied to core particles having a small particle size, it is easy to cause aggregation of particles and non-uniformity of the resin layer, and it is extremely difficult to produce a coated carrier. difficult.
Therefore, the copolymer according to the present invention preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 10,000 to 70,000, and 30,000 to 40,000. More preferably it is. When the weight average molecular weight is less than 5,000, the strength of the resin layer is insufficient, and when it exceeds 100,000, the liquid viscosity of the composition for the resin layer becomes high and the carrier productivity is lowered.

  In the present invention, the resin layer has no film defects, and the average film thickness is preferably 0.05 to 0.50 μm. When the average film thickness is 0.05 μm or more, the resin layer is less likely to be destroyed by use, and the film is not scraped. When the average film thickness is 0.50 μm or less, the resin layer is not a magnetic material, so Adhesion is less likely to occur, and the resistance adjusting effect is sufficiently exhibited.

(Core material)
In the present invention, the carrier core particle is not particularly limited as long as it is a magnetic substance, but is not limited to ferromagnetic metals such as iron and cobalt; iron oxides such as magnetite, hematite and ferrite; various alloys and compounds; Resin particles in which is dispersed in a resin. Of these, Mn-based ferrite, Mn-Mg-based ferrite, Mn-Mg-Sr ferrite, and the like are preferable from the viewpoint of environmental considerations.

  The carrier core material preferably has a shape factor SF2 in the range of 120 to 160 and an arithmetic average surface roughness Ra in the range of 0.5 to 1.0 μm. By setting the core material shape within a specified range, it is possible to obtain a carrier that is particularly excellent in charging stability and resistance stability over time. Although the details of this reason are not clear, by setting the core shape factor and arithmetic average surface roughness within the specified ranges, the carrier has an appropriately concavo-convex shape, thereby scraping the spent toner on the carrier. This is thought to be due to the effect of preventing the decrease in charge and increase in resistance due to spent. When the SF2 of the core particle is 120 or more, the uneven shape as intended in the present invention is obtained, and the spent scraping effect is obtained. In addition, when the core particle has an SF2 of 160 or less, the core material is not excessively exposed when used in a developing machine for a long time in actual use, and the initial resistance value and the resistance value after use change. The image quality is stable without changing the amount of toner on the electrostatic latent image carrier and how it is loaded.

The shape factors SF1 and SF2 mean the following. SF1 and SF2 indicating the shape factor are, for example, 100 carrier particle images that have been magnified 300 times using FE-SEM (S-800) manufactured by Hitachi, Ltd., and the image information is obtained via the interface. For example, it introduces into an image analysis apparatus (Luzex AP) manufactured by Nireco Corporation, performs analysis, and values obtained from the following formulas (1) and (2) are defined as shape factors SF1 and SF2.
SF1 = (L ² / A) × (π / 4) × 100 (1)
SF2 = (P ² / A) × (1 / 4π) × 100 (2)
In the formula, L is the absolute maximum length of the particle (the length of the circumscribed circle), P is the peripheral length of the particle, and A is the projected area of the particle. The shape factor SF1 indicates the degree of roundness of the particles, and the shape factor SF2 indicates the degree of unevenness of the particles. The value of SF1 increases as the distance from the circle (spherical) increases. When the irregularities on the surface become severe, the value of SF2 increases.

  In the present invention, the arithmetic average surface roughness Ra means the following. Use OPTELICS C130 manufactured by LASERTEC, and after capturing an image with a magnification of 50x objective lens and Resolition 0.20 μm, the observation area is 10 μm × 10 μm centering on the apex of the core, and the number of cores is 100 The measured value was used.

(Carrier particles)
The carrier particles preferably have a volume average particle size of 32 μm or more and 40 μm or less. When the volume average particle diameter of the carrier particles is 32 μm or more, carrier adhesion does not occur, and when it is 40 μm or less, the reproducibility of image details does not deteriorate and a fine image can be formed. The volume average particle diameter can be measured using, for example, a Microtrac particle size distribution model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).

(toner)
The two-component developer of the present invention has the carrier and toner of the present invention.
The toner contains a binder resin and a colorant, and may be a monochrome toner or a color toner. Further, the toner particles may contain a release agent in order to be applied to an oilless system in which toner fixing prevention oil is not applied to the fixing roller. Such toner generally tends to cause filming. However, since the carrier of the present invention can suppress filming, the developer of the present invention maintains good quality for a long time. Can do.
Further, color toners, particularly yellow toners, generally have a problem that color stains are generated due to scraping of the resin layer of the carrier. However, the developer of the present invention can suppress the occurrence of color stains.

The toner can be produced using a known method such as a pulverization method or a polymerization method. For example, when a toner is manufactured using a pulverization method, first, a melt-kneaded product obtained by kneading a toner material is cooled, pulverized, and classified to prepare base particles. Next, in order to further improve transferability and durability, an external additive is added to the base particles to produce a toner.
At this time, the apparatus for kneading the toner material is not particularly limited, but a batch type two roll; Banbury mixer; KTK type twin screw extruder (manufactured by Kobe Steel), TEM type twin screw extruder (Toshiba Machine) A continuous twin screw extruder such as a twin screw extruder (manufactured by KCK), a PCM type twin screw extruder (manufactured by Ikegai Iron Works), a KEX type twin screw extruder (manufactured by Kurimoto Iron Works); Examples thereof include a continuous single-shaft kneader such as Ko Nida (manufactured by Buss).

Further, when the cooled melt-kneaded product is pulverized, it is roughly pulverized using a hammer mill, a rotoplex, etc., and then finely pulverized using a fine pulverizer using a jet stream, a mechanical pulverizer or the like. be able to. In addition, it is preferable to grind | pulverize so that an average particle diameter may be set to 3-15 micrometers.
Furthermore, when classifying the crushed melt-kneaded material, a wind classifier or the like can be used. In addition, it is preferable to classify so that the average particle diameter of the base particles is 5 to 20 μm.
In addition, when an external additive is added to the base particle, the external additive adheres to the surface of the base particle while being pulverized by mixing and stirring using a mixer.

The binder resin is not particularly limited, but is a homopolymer of styrene such as polystyrene, poly-p-styrene, polyvinyltoluene and the like; and a styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene. -Vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer Styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene Copolymer, styrene-isoprene copolymer Styrene copolymers such as styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid Rosin, modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin and the like, and two or more of them may be used in combination.
The binder resin for pressure fixing is not particularly limited, but polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene; ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer. Olefin copolymers such as ethylene-methacrylate copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin; epoxy resin, polyester, styrene-butadiene copolymer, polyvinylpyrrolidone, Examples thereof include methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and the like, and two or more of them may be used in combination.

  Although it does not specifically limit as a coloring agent (pigment or dye), Cadmium yellow, mineral fast yellow, nickel titanium yellow, Navels yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, Yellow pigments such as permanent yellow NCG and tartrazine lake; orange pigments such as molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK; bengara, cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine Red pigments such as B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B; purple pigments such as fast violet B, methyl violet lake; cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, Blue pigments such as phthalocyanine blue partially chlorinated, First Sky Blue, Indanthrene Blue BC; Green pigments such as Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake; Carbon Black, Oil Furnace Black, Channel Black, Lamp Black Azine dyes such as acetylene black and aniline black, black pigments such as metal salt azo dyes, metal oxides and composite metal oxides, etc. It may be.

  The release agent is not particularly limited, but includes polyolefins such as polyethylene and polypropylene, fatty acid metal salts, fatty acid esters, paraffin wax, amide wax, polyhydric alcohol wax, silicone varnish, carnauba wax, ester wax and the like. Two or more kinds may be used in combination.

  The toner may further contain a charge control agent. The charge control agent is not particularly limited, but nigrosine; an azine dye having an alkyl group having 2 to 16 carbon atoms (see Japanese Patent Publication No. 42-1627); I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Basic dyes such as Basic Green 4 (C.I. 42000); lake pigments of these basic dyes; I. Solvent Black 8 (C.I. 26150), quaternary ammonium salts such as benzoylmethylhexadecyl ammonium chloride and decyltrimethyl chloride; dialkyltin compounds such as dibutyl and dioctyl; dialkyltin borate compounds; guanidine derivatives; vinyl having an amino group Polyamine resins such as polycondensation polymers and condensation polymers having amino groups; described in JP-B-41-20153, JP-B-43-27596, JP-B-44-6397, and JP-B-45-26478 Metal complex salts of monoazo dyes; salicylic acids described in JP-B-55-42752 and JP-B-59-7385; dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr, Fe, etc. Metal complexes of Examples thereof include honed copper phthalocyanine pigments; organic boron salts; fluorine-containing quaternary ammonium salts; calixarene compounds, and the like. For color toners other than black, white metal salts of salicylic acid derivatives are preferred.

  The external additive is not particularly limited, but inorganic particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride, etc .; poly having an average particle size of 0.05 to 1 μm obtained by a soap-free emulsion polymerization method Examples thereof include resin particles such as methyl methacrylate particles and polystyrene particles, and two or more kinds may be used in combination. Among these, metal oxide particles such as silica and titanium oxide whose surfaces are hydrophobized are preferable. Furthermore, by using a combination of hydrophobized silica and hydrophobized titanium oxide, the amount of added hydrophobized titanium oxide is higher than that of hydrophobized silica. A toner having excellent charging stability can be obtained.

(Replenishment developer)
By applying the carrier of the present invention to a replenishment developer composed of a carrier and a toner and applying it to an image forming apparatus that forms an image while discharging excess developer in the developing device, a stable image can be obtained over a very long period of time. Quality is obtained. That is, the deteriorated carrier in the developing device and the non-deteriorated carrier in the replenishing developer are replaced, and the charge amount is kept stable over a long period of time, so that a stable image can be obtained. This method is particularly effective when printing a large image area. When printing a large image area, carrier charge deterioration due to toner spent on the carrier is the main carrier deterioration. However, when this method is used, the carrier replenishment amount increases when the image area is large, and the deteriorated carrier is replaced. Increases frequency. Thereby, a stable image can be obtained for an extremely long period of time.

  The mixing ratio of the replenishment developer is preferably 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier. When the amount of toner is 2 parts by mass or more, the carrier supply amount does not become excessive, and the charge amount of the developer is difficult to increase. As the developer charge amount increases, the developing ability decreases and the image density decreases. In the case of 50 parts by mass or less, since the carrier ratio in the replenishment developer increases, the replacement of carriers in the image forming apparatus increases, and an effect on carrier deterioration can be expected.

The toner storage unit in the present invention is a unit in which the developer of the present invention is stored in a unit having a function of storing toner. Here, examples of the toner storage unit include a developer storage container, a developing device, and a process cartridge.
The developer container is a container that contains a developer.
The developing unit is a unit having a means for containing and developing a developer.
The process cartridge is a cartridge in which at least the electrostatic latent image carrier and the developing unit are integrated, accommodates a developer, and is detachable from the image forming apparatus. The process cartridge may further include at least one selected from a charging unit, an exposure unit, and a cleaning unit.

(Image forming method)
The image forming method of the present invention comprises a step of forming an electrostatic latent image on an electrostatic latent image carrier, and an electrostatic latent image formed on the electrostatic latent image carrier using the two-component development of the present invention. Developing with a developer to form a toner image, transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and fixing the toner image transferred to the recording medium Process.

(Image forming device)
The image forming apparatus of the present invention includes an electrostatic latent image carrier, a charging unit that charges the electrostatic latent image carrier, an exposure unit that forms an electrostatic latent image on the electrostatic latent image carrier, Developing means for developing the electrostatic latent image formed on the electrostatic latent image carrier using a developer to form a toner image; and a toner image formed on the electrostatic latent image carrier. A transfer means for transferring to the recording medium; and a fixing means for fixing the toner image transferred to the recording medium; and other means appropriately selected as necessary, for example, a charge eliminating means, a cleaning means, The apparatus comprises recycling means, control means, etc., and uses the two-component developer of the present invention as the developer.

In the present embodiment, the two-component developer including the carrier and the toner described above is used in the trickle development system as a replenishment developer and a developer for developing device, so that even after long-term use. Therefore, sufficient charge control can be performed for image quality required in the field of production printing, and high durability can be achieved.
The configuration of the image forming apparatus used in the present invention is not particularly limited, and an image forming apparatus having another configuration can be used as long as it has a similar function. .
The developing device internal developer preferably contains 3 to 15 parts by mass of toner with respect to 100 masses of carrier.

  FIG. 1 is a schematic diagram showing the configuration of the image forming apparatus of the present invention. In FIG. 1, a tandem type image forming apparatus having four image forming stations, each of which forms an image of a different color and finally obtains a color image. Hereinafter, the image formation will be described.

  The image forming apparatus 1 includes a document transport device (ADF) 5 that transports a document, a scanner unit 4 for reading a document, and a digital signal output from the scanner unit electrically processed by the image processing unit. The image forming unit 3 forms an image on a recording sheet based on a digital signal output from the processing unit. In the scanner unit 4, an image of a document placed on the document placement table is read by a color CCD through an irradiation lamp, a mirror, and a lens, and the data is sent to the image processing unit. In the image processing unit, necessary processing is performed on the data, converted into an image signal, and sent to the image forming unit 3.

In the image forming unit 3, four image forming stations 10Y, 10C, 10M, and 10K using yellow (Y), cyan (C), magenta (M), and black (K) toners are arranged in parallel. One intermediate transfer belt 21 and one secondary transfer roller 25 are provided for one image forming station 10. As an example of the image forming station 10 constituting the image forming apparatus 1, a configuration of a yellow image forming station 10Y is shown. In particular, the other cyan image forming station 10C, magenta image forming station 10M, and black image forming station 10K have the same configuration and operation unless otherwise described.
The image forming station 10 can be used as a process cartridge 10 that can be attached to and detached from the main body of the image forming apparatus 1.
When the image forming operation is started, in the yellow image forming station 10Y, the surface of the photoreceptor 11 as the electrostatic latent image carrier is uniformly charged by the charging device 12 as the charging means. The photoreceptors 11Y, 11C, 11M, and 11K in which the organic photoreceptor layer is formed on the electrically grounded cored bar are uniformly negatively charged by the charging devices 12Y, 12C, 12M, and 12K using the corona discharge. After that, the exposure devices 30Y, 30C, 30M, and 30K including the light emitting means including the respective laser diodes irradiate light to the image portions corresponding to the respective colors, and electrostatically charge the photosensitive members 11Y, 11C, 11M, and 11K. A latent image is formed.
Then, an electrostatic latent image of a yellow component image of a full-color original is formed on the charged photoconductor 11 by exposure from an optical writing exposure device 30, and the electrostatic latent image is developed by a yellow developing device 13Y as developing means. It is visualized with yellow toner. In addition, similar image forming operations are performed in the cyan image forming station, the magenta image forming station, and the black image forming station 10 with a predetermined time difference, and toner images of cyan, magenta, and black are formed on each photoconductor 11. Is done. In order to superimpose the toner images Y, C, M, and Bk formed on the photoreceptor 11 at the image forming stations 10Y, 10C, 10M, and 10K as one full-color image on the intermediate transfer belt 21, the intermediate transfer is performed. On the back side of the belt 21, a primary transfer roller 23 is disposed at a position opposite to the photoconductor 11 of each image forming station 10, and a predetermined transfer bias is applied to the primary transfer roller 23, whereby the toner of each image forming station 10. The images are successively transferred onto the intermediate transfer belt 21 in a superimposed manner.

The surface potential of the photoconductor 11 in each image forming station 10 after transfer to the intermediate transfer belt 21 is neutralized by an optical neutralization unit, and residual transfer toner remaining on the photoconductor 11 is cleaned by a cleaning device 19 as a cleaning unit. A series of image forming cycles such as removal by the blade and charging by the above-described charging device 12 are repeated. After the transfer by the intermediate transfer belt 21, the surface of the photoconductor 11 is neutralized by an optical neutralization unit, and then a residue such as toner is removed by a cleaning device 19. The toner removed by the cleaning device 19 is transported to a waste toner storage tank through a waste toner transport path.
Deposits such as toner and paper dust remaining on the surface of the intermediate transfer belt 21 after the transfer of the full-color toner image onto the recording paper are removed by the cleaning brush roller and the cleaning blade of the intermediate transfer belt cleaning device 22, and the above-described photoconductor. In the same manner as the waste toner, it is conveyed to a waste toner container. A tension roller 211 (a roller facing the transfer roller 25) 212, 213 provided in a transfer unit including the intermediate transfer belt 21, a transfer bias power source, a belt drive shaft, and the like applies tension to the transfer belt by a cam mechanism. By releasing, the intermediate transfer belt 21 can be changed between a state where it is in contact with the photoconductor 11 of each image forming station 10 and a state where it is separated.
As a result, when the machine is operating, the photosensitive member 11 of each image forming station 10 is brought into contact before the rotation, and when the machine is stopped, the photosensitive member 11 is separated from the photosensitive member 11. After the toner image is transferred to the intermediate transfer belt 21, the surface of the photoreceptor is neutralized by the light neutralization unit, and the cleaning device 19 first (upstream position in the rotation direction of the photoreceptor in the cleaning unit) first counters the rotation direction of the photoreceptor. Rotate the brush roller in the direction to disturb the residual toner and adhering matter on the photosensitive member to weaken the adhesive force with the photosensitive member 11, and contact the blade made of a rubber elastic body with the photosensitive member 11 at the downstream position. In this way, the above-described disturbed toner and deposits are removed.

Thereafter, the toner image transferred to the intermediate transfer belt 21 is synchronized with the secondary transfer roller 25 to which a predetermined bias is applied to the toner image on the intermediate transfer belt 21 that has become one full-color image. Then, it is transferred onto the recording paper conveyed. The transfer device 20 includes a primary transfer roller 23, a secondary transfer roller 25, an intermediate transfer belt 21, an intermediate transfer belt cleaning device 22, and the like.
Further, the recording sheets selected from the plurality of sheet feeding cassettes 40 arranged in the sheet feeding apparatus 2 by the pick-up roller 42 from the sheet feeding cassette 40 are selected one by one from the sheet feeding cassette 40. Pulled out. Then, the image is conveyed to the image forming unit 3 by the conveyance roller 43. Then, the registration roller 44 measures the timing of the toner image on the intermediate transfer belt 21 and sends it to the secondary transfer roller 25.
Thereafter, the recording paper onto which the toner image has been transferred is conveyed to the fixing device 50 and heated and pressurized to fix the toner image on the recording paper and output a full color image.
When performing duplex printing, the image is fed back to the duplex conveying unit 32 before being sent from the image fixing device to the paper discharge tray 48. Thereafter, it is sent again to the previous registration roller 44 and printing on the second surface is performed.

In the developing device 13, a developing sleeve provided with a magnetic field generating unit is disposed at a position facing the photoconductor 11. The charging device 12 makes a charging roller, which is a charging member disposed opposite to the photoconductor 11, contact or non-contact, and applies a predetermined voltage from a power source to uniformly charge the surface of the photoconductor 11.
The cleaning device 19 has a cleaning blade for the photoreceptor 11. Further, a recovery blade, a film, and the like for recovering the cleaned toner and a recovery coil for transporting the toner are provided. The cleaning blade is made of a material such as metal, resin, rubber, etc., and rubbers such as fluorine rubber, silicone rubber, butyl rubber, butadiene rubber, isoprene rubber, urethane rubber are preferably used, and among these, urethane rubber is particularly preferable. In addition, a lubricant application device that applies a fluororesin, a silicone resin, and a metal stearate compound such as zinc stearate or aluminum stearate as a lubricant may be provided. In FIG. 1, 24 is a conveyance belt, and 47 is a discharge roller.

In FIG. 1, the image forming station 10 used in the image forming apparatus of the present invention also functions as a process cartridge.
FIG. 2 is a schematic view showing an example of the configuration of the process cartridge of the present invention. As shown in FIG. 2, in the process cartridge 10, a charging device 12, a developing device 13, and a cleaning device 19 are disposed around the photoconductor 11. The process cartridge 10 only needs to include at least the photoconductor 11 and other process devices. A latent image is formed on the photoconductor 11 by the laser light L emitted from the exposure device 30 disposed on the upper portion. The process cartridge 10 is detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these. “Part” represents part by mass.

(Charging performance imparting fine particles)
[Charging performance imparting fine particles C1]
Magnesium oxide (Star Mag PSF manufactured by Kamijima Chemical Co., Ltd.) is used as the charging performance-imparting fine particles C1. When the average particle size of the fine particles was measured using Nanotrac UPA series (manufactured by Nikkiso Co., Ltd.), the average particle size was 1050 [nm]. The average particle diameter is a value of a volume average particle diameter obtained by dispersing particle to be measured (magnesium oxide particles) so as to have a constant concentration in a methanol solvent and performing particle size measurement. The average particle size of the charging performance-imparting fine particles described below is also measured by the same method.

[Charging performance imparting fine particles C2]
Magnesium oxide (Kyowa Mag MF150 manufactured by Kyowa Chemical Industry Co., Ltd.) is used as the charging performance imparting fine particles C2. When the average particle diameter of the fine particles was measured, the average particle diameter was 700 [nm].

[Charging performance imparting fine particles C3]
What adjusted magnesium oxide (Pyroxuma 5Q-S by Kyowa Chemical Industry Co., Ltd.) by classification is used as the charging performance imparting fine particles C3. When the average particle diameter of the obtained fine particles was measured, the average particle diameter was 1450 [nm].

[Charging performance imparting fine particles C4]
Magnesium oxide (Pyroxuma 5Q-S manufactured by Kyowa Chemical Industry Co., Ltd.) is used as the charging performance imparting fine particles C4. When the average particle diameter of the fine particles was measured, the average particle diameter was 1770 [nm].

[Charging performance imparting fine particles C5]
Magnesium oxide (Kyowa Mag MF30 manufactured by Kyowa Chemical Industry Co., Ltd.) is used as the charging performance imparting fine particles C5. When the average particle diameter of the fine particles was measured, the average particle diameter was 550 [nm].

[Charging performance imparting fine particles C6]
Magnesium oxide (PUREMAG FNM-G manufactured by Tateho Chemical Industry Co., Ltd.) prepared by classification is used as the charging performance imparting fine particles C6. When the average particle diameter of the obtained fine particles was measured, the average particle diameter was 460 [nm].

(Conductive fine particle production example)
[Conductive fine particle production example 1]
100 g of aluminum oxide (AKP-30 manufactured by Sumitomo Chemical Co., Ltd.) was dispersed in 1 liter of water to form a suspension, and this liquid was heated to 70 ° C. A suspension of 135 g of stannic chloride and 4.0 g of phosphorus pentoxide in 1.7 liters of 2N hydrochloric acid and 12% by mass aqueous ammonia was added to the suspension so that the suspension had a pH of 7-8. It was added dropwise over a period of 40 minutes. After dropping, the cake obtained by filtering and washing the suspension was dried at 110 ° C. Next, this dry powder was treated in a nitrogen stream at 500 ° C. for 1 hour to obtain conductive fine particles P1.

(Resin synthesis example)
[Resin synthesis example 1]
300 g of toluene was charged into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Subsequently, 3-methacryloxypropyltris (trimethylsiloxy) silane 84. shown by CH ₂ = CMe—COO—C ₃ H ₆ —Si (OSiMe ₃ ) ₃ (wherein Me is a methyl group) is added. 4 g (200 mmol: Silaplane TM-0701T / manufactured by Chisso Corporation), 3-methacryloxypropylmethyldiethoxysilane 39 g (150 mmol), methyl methacrylate 65.0 g (650 mmol), and 2,2′- A mixture of 0.58 g (3 mmol) of azobis-2-methylbutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, a solution prepared by dissolving 0.06 g (0.3 mmol) of 2,2′-azobis-2-methylbutyronitrile in 15 g of toluene was further added (2,2′-azobis-2-methylbutyrate). A total amount of ronitrile (0.64 g = 3.3 mmol) was mixed at 90 to 100 ° C. for 3 hours and radical copolymerized to obtain a methacrylic copolymer R1.

(Example of carrier production)
[Carrier Production Example 1]
33 parts by mass of a methyl silicone resin having a weight molecular weight of 15,000 (solid content 25%) prepared from a bifunctional or trifunctional monomer, 11 parts by mass of resin R1 (solid content 25%) obtained in Resin Synthesis Example 1, 14 parts by mass of the charging performance imparting fine particles C1, 11 parts by mass of the conductive fine particles P1, 2 parts by mass of titanium diisopropoxybis (ethylacetoacetate) TC-750 (manufactured by Matsumoto Fine Chemical Co.) as a catalyst, and SH6020 as a silane coupling agent 0.3 parts by mass (manufactured by Toray Silicone Co., Ltd.) was diluted with toluene to obtain a resin solution having a solid content of 10 wt%. This resin solution was coated and dried on 1000 parts by mass of Mn ferrite particles having a weight average particle diameter of 35 μm by using a fluidized bed type coating apparatus while controlling the temperature in the fluidized tank at 70 ° C. The obtained carrier was baked in an electric furnace at 180 ° C./2 hours to obtain carrier A.
It was 1060 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

[Carrier Production Example 2]
In Carrier Production Example 1, Carrier B was obtained in exactly the same manner except that 28 parts by mass of C1 was used as the charging performance imparting fine particles.
It was 1060 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

[Carrier Production Example 3]
Carrier C was obtained in exactly the same manner as Example 1 except that 8 parts by mass of C2 was used as the charging performance-imparting fine particles.
It was 710 nm when the average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier.

[Carrier Production Example 4]
In Carrier Production Example 1, Carrier D was obtained in exactly the same manner except that 8 parts by mass of C3 was used as the charging performance imparting fine particles.
It was 1470 nm when the average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier.

[Carrier Production Example 5]
Carrier E was obtained in exactly the same manner as Example 1 except that 8 parts by mass of C4 was used as the charging performance-imparting fine particles.
It was 1790 nm when the average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier.

[Carrier Production Example 6]
Carrier F was obtained in exactly the same manner as Example 1 except that 21 parts by mass of C5 was used as the charging performance-imparting fine particles.
The average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier, and it was 530 nm.

[Carrier Production Example 7]
In Carrier Production Example 1, Carrier G was obtained in exactly the same manner except that 21 parts by mass of C6 was used as the charging performance imparting fine particles.
It was 460 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

[Carrier Production Example 8]
In Carrier Production Example 1, 44 parts by mass of 15,000 weight molecular weight methylsilicone resin (solid content 25%) prepared from a bifunctional or trifunctional monomer was used to obtain the resin R1 ( Carrier H was obtained in the same manner except that the solid content (25%) was not used.
It was 1060 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

[Carrier Production Comparative Example 1]
Carrier a was obtained in the same manner as Example 1 except that the charging performance-imparting fine particles C1 were not used.

[Carrier Production Comparative Example 2]
Carrier b was obtained in exactly the same manner as Example 1 except that 37 parts by mass of C1 was used as the charging performance-imparting fine particles.
It was 1060 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

[Carrier Production Comparative Example 3]
Carrier production example 1 was obtained in exactly the same manner as Example 1 except that 21 parts by mass of C4 was used as the charging performance-imparting fine particles.
It was 1790 nm when the average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier.

[Carrier Production Comparative Example 4]
Carrier d was obtained in the same manner as Example 1 except that 5 parts by mass of C2 was used as the charging performance-imparting fine particles.
It was 710 nm when the average particle diameter of the charging performance-imparting fine particles in the carrier coat resin layer was measured from the cross section SEM of the obtained carrier.

[Carrier Production Comparative Example 5]
Carrier production example 1 was obtained in exactly the same manner as Example 1 except that 8 parts by mass of C6 was used as the charging performance-imparting fine particles.
It was 460 nm when the average particle diameter of the charging performance provision fine particle in a carrier coat resin layer was measured from cross section SEM of the obtained carrier.

The obtained carrier was measured for the amount of Mg exposed on the carrier surface by AXIS / ULYRA (manufactured by Shimadzu / KRATOS). Table 1 shows the measurement results of the Mg exposure amount of each carrier, the average particle diameter D, and the content of the charging performance-imparting fine particles.

(Example of toner production)
<Example of toner production>
[Synthesis Example of Polyester Resin A]
443 parts of PO adduct of bisphenol A (hydroxyl value 320), 135 parts of diethylene glycol, 422 parts of terephthalic acid, and 2.5 parts of dibutyltin oxide are placed in a reaction vessel equipped with a thermometer, a stirrer, a cooler and a nitrogen introduction tube. Then, the reaction was carried out at 200 ° C. until the acid value reached 10 to obtain [Polyester Resin A]. The resin had a Tg of 63 ° C. and a peak number average molecular weight of 6000.

[Synthesis example of polyester resin B]
443 parts of PO adduct of bisphenol A (hydroxyl value 320), 135 parts of diethylene glycol, 422 parts of terephthalic acid, and 2.5 parts of dibutyltin oxide are placed in a reaction vessel equipped with a thermometer, a stirrer, a cooler and a nitrogen introduction tube. Then, the reaction was carried out at 230 ° C. until the acid value became 7, to obtain [Polyester Resin B]. The resin had a Tg of 65 ° C. and a peak number average molecular weight of 16000.

[Manufacture of base toner particles 1]
Polyester resin A ... 40 parts Polyester resin B ... 60 parts Carnauba wax ... 1 part Carbon black (# 44 manufactured by Mitsubishi Chemical) ... 15 parts Toner composition The materials are mixed with a Henschel mixer (Mitsui Mining Co., Ltd., Henschel 20B, 1500 rpm for 3 minutes) and kneaded with a single-screw kneader (Buss Co., Ltd. small bus-co-kneader) under the following conditions (set temperature) : Feeder: 2 kg / Hr) at an inlet portion of 100 ° C. and an outlet portion of 50 ° C., and [Base toner A1] was obtained.

Further, the [base toner A1] was kneaded and then cooled by rolling, pulverized by a pulverizer, and further an I-type mill (IDS-2 type manufactured by Nippon Pneumatic Co., Ltd., using a flat impact plate, air pressure: 6.8 atm). / Cm ² , feed amount: 0.5 kg / hr) was finely pulverized, and further classified (132MP manufactured by Alpine) to obtain [base toner particles 1].

(External additive treatment)
To 100 parts of “base toner particle 1”, 1.0 part of hydrophobic silica fine particles (R972: manufactured by Nippon Aerosil Co., Ltd.) was added as an external additive and mixed with a Henschel mixer to obtain toner particles (hereinafter “toner toner”). 1 ”).

[Creation of developers A to H and a to e]
To the carriers A to H and a to e (93 parts) obtained in the carrier production example, 7.0 parts of the toner 1 (volume average particle diameter 7.2 μm) obtained in the toner production example was added, Were stirred for 20 minutes to prepare developers A to H and a to e.

(Evaluation)
Running evaluation was implemented using the obtained developing agent. Using RICOH Pro C7110S (Ricoh Digital Color Copier / Printer Combined Machine) manufactured by Ricoh Company with the developers A to H and a to e of Examples and Comparative Examples, 10,000 sheets at an image area ratio of 40%, and 100 Toner scattering, background fogging, and ghost images after running 10,000 sheets were evaluated.

<Toner scattering>
One of the important aims of the present invention is that the charging performance-imparting fine particles can provide a stable charging ability over a long period from the start of use. One method for evaluating the aim is toner scattering evaluation.
The toner collected at the lower part of the developer carrying member after running 10,000 sheets and 1 million sheets was sucked and collected, and the toner mass was measured. The evaluation criteria are shown below.
0 mg to less than 50 mg: ◎ (very good)
50 mg to less than 100 mg: ○ (good)
100 mg or more and less than 250 mg: Δ (can be used)
250 mg or more: × (defect)

<Skin cover>
One of the important aims of the present invention is that the charging performance-imparting fine particles can provide a stable charging ability over a long period from the start of use. One of the methods for evaluating the aim is a background fogging evaluation.
After running 10,000 and 1,000,000 sheets, the blank image is stopped during development, and the toner on the photoconductor after development is transferred to tape, and the difference (ΔID) from the image density of the untransferred tape is 938 spectrodent. Measurement was performed with a meter (manufactured by X-Rite). The evaluation criteria are shown below.
0 or more and less than 0.005: ◎ (very good)
0.005 or more to less than 0.01: ○ (good)
0.01 or more and less than 0.02: △ (can be used)
0.02 or more: × (defect)

<Ghost image>
As the ghost image, an A4 size vertical band chart shown in FIG. 3A having an image area ratio of 8% is printed, and (a1) to (a3) and (b1) shown in FIG. To (b3) were measured by X-Rite 938 (manufactured by X-Rite), the difference in concentration between (a1) and (b1), the difference in concentration between (a2) and (b2), and (a3) and (b3) , And the average of the above three measured density differences was defined as ΔID, and was ranked below.
◎: Very good, ○: Good, Δ: Acceptable, ×: Unusable level for practical use ◎, ○, △ were accepted and x was rejected.
A: 0.01 ≧ ΔID
○: 0.01 <ΔID ≦ 0.03
Δ: 0.03 <ΔID ≦ 0.06
×: 0.06 <ΔID

The evaluation results are shown in Table 2 above.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Paper feeder 3 Image forming part 4 Scanner part 5 Automatic document feeder (ADF)
10 Image forming station (process cartridge)
DESCRIPTION OF SYMBOLS 11 Photoconductor 12 Charging device 13 Developing device 19 Cleaning device 20 Transfer device 21 Intermediate transfer belt 22 Intermediate transfer belt cleaning device 23 Primary transfer roller 24 Transport belt 25 Secondary transfer roller 30 Exposure device 32 Double-sided transport unit 40 Paper feed cassette 42 Pickup Roller 43 Conveying roller 44 Registration roller 47 Discharge roller 48 Discharge tray 50 Fixing device

JP-A-11-202560 JP 2006-39357 A JP 2010-117519 A Japanese Patent No. 5534409 JP 2011-209678 A JP 2009-63805 A

Claims (8)

  A carrier for an electrostatic latent image developer having core particles and a resin layer covering the core particles, wherein the resin layer contains magnesium oxide fine particles, and the Mg exposure amount on the carrier surface is 3.0 to A carrier for an electrostatic latent image developer, wherein the carrier is 15.0 [atomic%].   The carrier for an electrostatic latent image developer according to claim 1, wherein an average particle diameter D in the carrier cross-sectional image of the magnesium oxide fine particles is 500 to 1500 [nm]. The resin of the resin layer contains a crosslinked product of a copolymer containing a structural unit represented by the following general formula (A) and a structural unit represented by the general formula (B). Or the electrostatic latent image developer carrier according to 2;
(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom or methyl group m: integer of 1 to 8 R ² : alkyl group having 1 to 4 carbon atoms R ³ : alkyl group having 1 to 8 carbon atoms, or alkoxy group having 1 to 4 carbon atoms X : 10 to 90 mol%
Y: 10 to 90 mol%
However, X and Y represent the composition ratio of the structural unit represented by the general formula (A) and the structural unit represented by the general formula (B) in the copolymer. )   A two-component developer comprising the electrostatic latent image developer carrier and the toner according to claim 1.   The two-component developer according to claim 4, wherein the toner is a color toner.   A replenishment developer containing a carrier and a toner, the toner containing 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier, wherein the carrier is the electrostatic latent image developer according to any one of claims 1 to 3. A developer for replenishment, characterized by being a carrier for use.   A toner storage unit comprising the two-component developer according to claim 4 or 5 or the replenishment developer according to claim 6.   An electrostatic latent image carrier, charging means for charging the electrostatic latent image carrier, exposure means for forming an electrostatic latent image on the electrostatic latent image carrier, and on the electrostatic latent image carrier A developing means for developing the electrostatic latent image formed on the toner using the two-component developer according to claim 4 to form a toner image, and a toner formed on the electrostatic latent image carrier An image forming apparatus comprising: transfer means for transferring an image to a recording medium; and fixing means for fixing a toner image transferred to the recording medium.