JP6182960B2 - Two-component developer carrier, electrostatic latent image developer, color toner developer, replenishment developer, image forming method, process cartridge including electrostatic latent image developer, and image forming apparatus using the same - Google Patents

Description

  The present invention relates to a carrier for developing an electrostatic latent image used in a two-component developer used in electrophotography and electrostatic recording, an electrostatic latent image developer, a color toner developer, and a replenishing development using the carrier The present invention relates to an agent, an image forming method, a process cartridge including an electrostatic latent image developer, 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.

  In full-color image formation, generally, color toners of three colors of yellow, magenta, and cyan or four color toners obtained by adding black to this are laminated to reproduce all colors. Therefore, in order to obtain a clear full color image with excellent color reproducibility, it is necessary to smooth the surface of the fixed toner image to reduce light scattering. For these reasons, the image gloss of conventional full-color copying machines and the like is often 10 to 50% of medium to high gloss.

  In general, as a method for fixing a dry toner image on a recording medium, a contact heating fixing method in which a roller or belt having a smooth surface is heated and pressed against the toner is frequently used. Such a method has high thermal efficiency and enables high-speed fixing, and can give gloss and transparency to a color toner image. On the other hand, the surface of the heat fixing member and the molten toner are brought into contact with each other under pressure. Then, in order to peel off, a so-called offset phenomenon occurs in which a part of the toner image adheres to the surface of the fixing roller and is transferred onto another image.

  In order to prevent such an offset phenomenon, the surface of the fixing roller is formed of silicone rubber or fluorine resin having excellent releasability, and further, an oil for preventing toner adhesion such as silicone oil is applied to the surface of the fixing roller. This method is generally adopted. However, such a method is very effective in preventing toner offset, but requires a device for supplying oil, and there is a problem that the fixing device is enlarged.

  For this reason, in monochrome image formation, an oilless system in which viscoelasticity at the time of melting is large and toner containing a release agent is used so that the melted toner does not break internally, so that no oil is applied to the fixing roller, or There is a tendency to adopt a system in which a small amount of oil is applied.

  On the other hand, in full-color image formation, as in the case of monochrome image formation, an oilless system tends to be employed for the purpose of downsizing the fixing device and simplifying the configuration. However, in full-color image formation, it is necessary to reduce the viscoelasticity of the toner at the time of melting in order to smooth the surface of the fixed toner image. Therefore, offset occurs more than in the case of monochrome image formation without gloss. This makes it difficult to adopt an oilless system. Further, when a toner containing a release agent is used, adhesion of the toner is increased and transferability to a recording medium is decreased. Furthermore, there is a problem in that the durability is lowered due to the occurrence of toner filming and a decrease in chargeability.

  On the other hand, as a carrier, prevention of toner filming, formation of a uniform surface, prevention of surface oxidation, prevention of decrease in moisture sensitivity, extension of developer life, prevention of adhesion to the surface of a photoreceptor, photosensitivity For the purpose of protecting the body from scratches or abrasion, controlling the charge polarity, adjusting the charge amount, etc., the carrier core material surface is coated with a resin having a low surface energy, such as a fluororesin or a silicone resin. Long life has been achieved.

  Examples of a carrier coated with a low surface energy resin include a carrier coated with a room temperature curable silicone resin and a positively chargeable nitrogen resin described in JP-A No. 55-127469 of Patent Document 1, A carrier coated with a coating material containing at least one modified silicone resin described in JP-A-55-157751, JP-A-56-140358 of Patent Document 3: a room temperature-curable silicone resin and a styrene / acrylic resin A carrier having a resin coating layer, a carrier in which the core particle surface described in JP-A-57-96355 of Patent Document 4 is coated with two or more layers of silicone resin so that there is no adhesion between the layers, Patent Document 5 Japanese Patent Laid-Open No. 57-96356 discloses a carrier in which a silicone resin is coated on the surface of a core particle, and Japanese Patent Laid-Open No. 58-96356. Positive chargeability coated with a material having a surface tension of 20 dyn / cm or less described in Japanese Patent Application Laid-Open No. Sho 61-110161 of Patent Document 7 Examples thereof include a carrier, a carrier coated with a coating material containing a fluorine alkyl acrylate described in JP-A-62-273576 of Patent Document 8, and a developer composed of a toner containing a chromium-containing azo dye.

  However, there has been a need for a carrier with higher durability, because it has been required to reduce the environmental waste load by further increasing the speed and life of the image forming apparatus in recent years and to reduce the printing cost per sheet.

By the way, there is a resistance value as an important physical property of the carrier. The resistance value of the carrier is adjusted so that the print quality can achieve the target in combination with the system of each image forming apparatus. As a material for adjusting the resistance value, conductive fine particles are contained in the resin layer of the carrier. Typical examples include carbon black, titanium oxide, zinc oxide, ITO (indium tin oxide), etc. Among them, single particle type carbon black and conductive layer coated type ITO are used as excellent conductive fine particles. There are many use cases. For example, JP-A-7-140723 in Patent Document 9, JP-A-8-179570 in Patent Document 10 and JP-A-8-286429 in Patent Document 11 describe carriers using carbon black as conductive fine particles. Have been described. However, it cannot cope with the increase in stress accompanying the recent increase in speed, and color stains have become a problem and need to be improved.
Also, Japanese Patent No. 4307352 of Patent Document 12, Japanese Patent Application Laid-Open No. 2006-79022 of Japanese Patent Application Laid-Open No. 2006-262155, Japanese Patent Application Laid-Open No. 2008-262155 of Japanese Patent Application Laid-Open No. 2009-186769, Japanese Patent Application Laid-Open No. 2009-186769, and Japanese Patent Application Laid-Open No. 2009-186769. Japanese Unexamined Patent Application Publication No. 2009-251483 discloses conductive fine particles obtained by coating ITO as a conductive material on base particles.
However, the structure of the conductive fine particles using the conductive material having excellent conductive performance is such that the substrate particles are coated with the conductive material as a thin film. When used in an image forming apparatus having a high printing speed by forming a carrier, Due to the collision between the carrier particles, the conductive material layer containing the conductive fine particles exposed on the surface of the carrier particles is scraped. As a result, the substrate with high hardness is exposed at an early stage, and further, the impact resistance of the carrier resin film is accelerated and the carrier film is scraped, resulting in a decrease in resistance. As a result, carrier scattering occurs. Inability to withstand long-term use.
As described above, in order to increase the durability of the carrier, not only the clothing resin but also the selection of conductive fine particles becomes important.

  The present invention relates to a carrier for developing an electrostatic latent image used in a two-component developer used in an electrophotographic method / electrostatic recording method enabling high durability, an electrostatic latent image developer using the carrier, It is an object of the present invention to provide a color toner developer, a replenishment developer, an image forming method, a process cartridge including an electrostatic latent image developer, and an image forming apparatus.

The inventors of the present invention have disclosed a conductive fine particle comprising a carrier for an electrostatic latent image developer, a resin layer coated with a conductive material containing tin oxide on a base of a white inorganic pigment, and containing phosphorus or tungsten. As a result, the inventors have found that durability can be ensured while maintaining the image quality over time by using a carrier having a specific configuration including the present invention.
Thus, the above problems are solved by the following (1) to (10) of the present invention.
(1) “A carrier for an electrostatic latent image developer comprising magnetic core material particles and a resin layer covering the surface thereof, wherein the resin layer contains conductive fine particles, wherein the conductive fine particles are at least white. A substrate containing an inorganic pigment is coated with a conductive layer containing tin oxide, and (tin peak intensity [kcps]) / (substrate element peak intensity [kcps] when the conductive fine particles are subjected to fluorescent X-ray analysis. ]), And the conductive fine particles contain one or more elements selected from phosphorus and tungsten in the electrostatic latent image developer. Career. "
(2) Peak intensity represented by “peak intensity [kcps] of one or more elements selected from phosphorus and tungsten when fluorescent X-ray analysis of the conductive fine particles is performed” / (tin peak intensity [kcps]) (2) “(Phosphorus or tungsten peak intensity [kcps]) / (tin peak intensity [when conducting X-ray fluorescence analysis of the conductive fine particles] kcps]) The carrier for electrostatic latent image developer according to item (1), wherein the peak intensity ratio is from 0.010 to 0.100. "
(3) The electrostatic latent image developer according to item (1) or (2), wherein the substrate of the conductive fine particles contains at least one selected from alumina or barium sulfate. For carrier. "
(4) The electrostatic latent image developer according to any one of (1) to (3) above, wherein the conductive fine particles contained in the resin layer have an average particle diameter of 200 to 700 nm. For carrier. "
(5) In any one of (1) to (4) above, wherein the carrier contains 50 to 500 parts by weight of conductive fine particles in the resin layer with respect to 100 parts by weight of the resin. The carrier for electrostatic latent image developer as described. "
(6) The static particle according to any one of (1) to (5) above, wherein the core particles have an SF-2 of 120 to 160 and an Ra of 0.5 to 1.0 μm. Carrier for electrostatic latent image developer. "
(7) “A two-component developer comprising the carrier and the toner according to any one of (1) to (6)”.
(8) “An electrostatic latent image carrier, charging means for charging the latent image carrier, exposure means for forming an electrostatic latent image on the latent image carrier, and on the electrostatic latent image carrier The electrostatic latent image formed on the toner is developed using the developer described in (7) above to form a toner image, and the toner image formed on the electrostatic latent image carrier is recorded. An image forming apparatus comprising: a transfer unit that transfers to a medium; and a fixing unit that fixes a toner image transferred to the recording medium.
(9) “An electrostatic latent image carrier, a charging member for charging the surface of the photoreceptor, and the electrostatic latent image formed on the electrostatic latent image carrier with the developer described in (7) A process cartridge comprising: a developing unit that uses and develops; and a cleaning member that cleans the electrostatic latent image carrier.
(10) The step of forming an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier with the developer described in (7) Developing the toner image to form a toner image; transferring the toner image formed on the electrostatic latent image carrier to a recording medium; fixing the toner image transferred to the recording medium; An image forming method comprising:
Further, the developer of the present invention includes the embodiments described in the following (11) to (13).
(11) “The developer according to (7) above, wherein the toner is a color toner.”
(12) “The developer according to (7), wherein the toner is a transparent toner.”
(13) “A replenishment developer including a carrier and a toner, the toner is contained in an amount of 2 to 50 parts by weight with respect to 1 part by weight of the carrier, and the carrier is any one of (1) to (6). Replenishment developer characterized by being a carrier of

As will be understood from the following detailed and specific description, according to the present invention, a core material particle having magnetism is coated with a conductive material containing tin oxide at a specific ratio on a base of a white inorganic pigment, In addition, a carrier obtained by applying a resin containing conductive fine particles containing phosphorus or tungsten and then subjecting the resin crosslinking component to condensation polymerization by heat treatment is provided.
In the carrier of the present invention, a tough film is formed by the silane-based cross-linking component having a small surface energy and the conductive fine particles, and the resistance is adjusted and the charging stability is excellent for a long period of time. It is possible to obtain a highly durable carrier and developer in which the pumping amount hardly changes, the coating is not scraped or peeled off, the toner spent is small, and the carrier adhesion can be suppressed.
Furthermore, the fluctuation of charging environment is suppressed, and the image density fluctuation, background stain, and in-machine contamination due to toner scattering do not occur in various usage environments.
In addition, a highly reliable development method and image forming apparatus can be provided.

It is a figure explaining the cell for measuring volume specific resistance in the present invention. It is a figure which shows an example of the process cartridge of this invention.

  The carrier of the present invention will be described in detail. The carrier for electrostatic latent image developer of the present invention is a carrier for electrostatic latent image developer comprising magnetic core material particles and a resin layer covering the surface thereof, and the resin layer contains conductive fine particles. The electrostatic latent image developer, wherein the conductive fine particles are conductive fine particles obtained by coating a white inorganic pigment substrate with a conductive material containing tin oxide at a specific ratio and containing phosphorus or tungsten. For carriers.

  The present invention uses a fine particle containing at least one element selected from phosphorus and tungsten by coating a resin layer with a conductive material containing tin oxide at a specific ratio on a substrate of a white inorganic pigment as a conductive fine particle. Is very important. As described above, carbon black and ITO have been used as an excellent resistance adjusting agent so far as conductive fine particles. However, with the increase in the speed of image forming apparatuses, carbon black becomes a color stain or ITO under high stress. In this case, the resistance decreases due to film scraping over time and needs to be improved.

(Conductive fine particles)
The conductive fine particles used in the present invention are characterized in that a white inorganic pigment substrate is coated with a conductive material containing tin oxide at a specific ratio and contains at least one element selected from phosphorus and tungsten. It is.
First, the ratio of the conductive material containing tin oxide to the substrate is the ratio of (tin peak intensity [kcps]) / (base element peak intensity [kcps]) peak intensity when conducting conductive X-ray fluorescence analysis. It is preferable that it is a ratio which becomes 1.5-12. This value range is characterized in that the amount of tin oxide, which is a conductive material, is very large compared to conductive fine particles using ITO, that is, the conductive material is a thick film. The conductive fine particles of the present invention are exposed on the surface of the carrier, and the conductive material layer is peeled off due to the collision between carriers in the developing machine in the image forming apparatus, like the conductive fine particles using ITO. Although it cannot be avoided, since the film is thickened, the hard substrate is not exposed at an early stage. For this reason, it is possible to maintain stable image quality over time without the carrier film sharpening progressing rapidly. When the ratio of (tin peak intensity [kcps]) / (substrate element peak intensity [kcps]) peak intensity ratio is less than 1.5, the conductive material layer of the conductive fine particles is scraped early to expose the substrate, and further the carrier film is scraped. May progress and image quality may deteriorate. On the other hand, if the peak intensity ratio of (tin peak intensity [kcps]) / (base element peak intensity [kcps]) is greater than 12, it is inevitably too thick and the conductive fine particles become too large. Since it becomes easy to detach at the initial stage and the effect of the conductive fine particles cannot be obtained, the image quality deteriorates.

  In the present invention, tin oxide in which one or more elements selected from phosphorus and tungsten are doped is used for the conductive material of the conductive fine particles. By adding a small amount of phosphorus or tungsten, it is possible to obtain a white conductive powder that is excellent in stability over time while having good conductive performance without lowering the whiteness and that is inexpensive. As a specific amount, a peak intensity ratio of (peak intensity [kcps] of one or more elements selected from phosphorus and tungsten) / (tin peak intensity [kcps]) when performing fluorescent X-ray analysis is 0.010. It is preferably ~ 0.100. When the peak intensity ratio is less than 0.010, desired conductivity cannot be obtained, and stability with time is poor. On the other hand, if it exceeds 0.100, the whiteness of the base pigment due to coloring decreases and the temporal stability is also poor. As an apparatus for fluorescent X-ray analysis, for example, ZSX-100E (Rigaku) can be used. The specific amount is quantified using fluorescent X-ray analysis because fluorescent X-ray analysis is bulk analysis. For example, when quantified by surface analysis such as X-ray photoelectron spectroscopy, since only the element on the outermost surface can be measured, one or more elements selected from phosphorus and tungsten are included in a sufficient amount intended by the present invention. This is because the target cannot be quantified when surface coating or the like is applied. There are other niobium, tantalum, antimony, and fluorine-doped products that use tin oxide as the conductive material, but phosphorus or tungsten is preferred from the standpoint of manufacturability, safety, and cost. is there.

  The conductive fine particles preferably have an average particle size in the range of 200 (nm) to 700 (nm), and more preferably in the range of 300 (nm) to 600 nm (nm). When the average particle diameter is less than 200 (nm), aggregation of the particles occurs and it becomes difficult to disperse into single particles, and when the carrier is formed, it exists as large conductive fine particles. Detachment is likely to occur. On the other hand, even if the average particle size exceeds 700 (nm), the detachment easily occurs. The average particle size of the conductive fine particles can be measured using, for example, Nanotrack UPA series (manufactured by Nikkiso Co., Ltd.).

  Any commercially available titanium dioxide, aluminum oxide, silicon dioxide, zinc oxide, barium sulfate, zirconium oxide, alkali metal titanate, or muscovite may be used as the white inorganic pigment as the base particles of the conductive fine particles. More specifically, the size of the particle is not limited, and the particle shape may be spherical, needle-like, or the like, and anatase type, rutile type, and amorphous type may be used. be able to. Although the present invention places importance on white, it can also be applied to various colored pigments such as iron oxide. Furthermore, it is more preferable to use aluminum oxide or barium sulfate for the base particles. This is because the charging stability is excellent when running for a long time with a developer for electrophotography using a carrier containing conductive fine particles using aluminum oxide or barium sulfate as a substrate. The reason for this is not clear, but the following reasons are conceivable.

  When running for a long period of time, the carrier film is scraped, and it is presumed that the substrate of conductive fine particles is exposed on the surface of the carrier. At this time, if the difference in electronegativity between the exposed conductive fine particle substrate and the toner external additive is small, it becomes impossible to give sufficient charge to the toner, which is presumed to cause charging failure. Conversely, if the difference in electronegativity is large, it is presumed that the chargeability is maintained even after long-term running. In many cases, titanium oxide or silicon dioxide is suitably used as an external additive for the toner, but these materials have a large electronegativity and are easily negatively charged. On the other hand, aluminum oxide and barium sulfate particularly preferably used as the base of the conductive fine particles of the present invention have a low electronegativity and are easily positively charged. For the above reason, a carrier having a resin coating layer containing conductive fine particles containing P- and / or W-doped tin oxide using aluminum oxide or barium sulfate as a base for conductive fine particles was used. It is considered that the charging stability when running for a long time with an electrophotographic developer is excellent.

The conductive fine particles in the present invention can be produced by various methods. For example, a tin salt hydrate layer containing a hydrate of phosphorus and / or tungsten salt is uniformly deposited on the surface of white inorganic pigment particles, It can manufacture by baking the obtained coating layer. In order to uniformly deposit a tin salt hydrate layer containing a hydrate of one or more salts selected from phosphorus and tungsten on the surface of the white inorganic pigment particles, for example, these phosphorus salts (for example, phosphorus pentoxide, POCl _3, etc.) And / or a salt of tungsten (for example, tungsten chloride, tungsten oxychloride, sodium tungstate, tungstic acid, etc.) and a tin salt (for example, tin chloride, tin sulfate, tin nitrate, etc.), sodium stannate, potassium stannate Such as stannate, tin alkoxide and other organic tin compounds), and deposited and deposited on the pigment particle surface in the form of hydrated phosphorus and / or tungsten and tin. A pH adjuster (for example, an aqueous base solution) to be simultaneously dropped into an aqueous solution in which white inorganic pigment particles are dispersed. In this case, it can be carried out while preventing dissolution and surface alteration of the white inorganic pigment particles due to acid and / or alkali. At this time, by adjusting the dropping amount of phosphorus and / or tungsten and the dropping amount of the tin chloride solution, It is possible to adjust the doping ratio of one or more elements selected from phosphorus and tungsten to SiO ₂ (however, the isoelectric point of tin hydrate, that is, tin hydroxide or stannic acid, phosphorus, tungsten component, etc.) Note that the electrical points are not necessarily the same and are not necessarily different in their solubility at a particular pH).
Also, for the purpose of reducing the aggressiveness of the white inorganic pigment particles during the dripping operation and the extreme hydration reaction of phosphorus and / or tungsten and tin and homogenizing the coating layer, for example, methanol, methyl ethyl ketone, etc. A water-soluble organic solvent can be mixed and used. The obtained hydrate can be calcined preferably at 300 to 850 ° C. in a non-oxidizing atmosphere, and as a result, the volume resistivity of the powder is very low compared to that heated in air. Can be suppressed.

  The conductive fine particles may be subjected to a surface treatment. By performing such a treatment, the upper conductive layer can be fixed uniformly and firmly on the particle surface, so that the resistance adjusting effect can be sufficiently exhibited. Amino silane coupling agents, methacryloxy silane coupling agents, vinyl silane coupling agents, and mercapto silane coupling agents can be used.

(Carrier coating resin)
As the coating resin for the carrier, silicon resin, 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 silicon 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 silicon 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 for the toner component to be spent and the accumulation of the spent component due to film scraping is difficult to obtain.

  As used herein, the term “silicon resin” refers to all commonly known silicon resins, such as straight silicon consisting only of organosilosan bonds, and silicon resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. However, it is not limited to this. Examples of commercially available straight silicon resins include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicon. In this case, it is possible to use the silicon 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, as modified silicone resin, KR206 (alkyd modified), KR5208 (acryl modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicon Co., Ltd. , SR2110 (alkyd modified) and the like.

  As the polycondensation catalyst, a titanium-based catalyst, a tin-based catalyst, a zirconium-based catalyst, and an aluminum-based catalyst can be mentioned. Of these various catalysts, among these titanium-based catalysts that give excellent results, Titanium diisopropoxybis (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.

  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 coating layer further preferably contains a cross-linked product of an acrylic resin and an amino resin.
Thereby, fusion | melting of coating 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 coating 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.
Commercially available silane coupling agents include AY43-059, SR6020, SZ6023, SH6026, SZ6032, SZ6050, AY43-310M, SZ6030, SH6040, AY43-026, 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 Silicone Co., Ltd.).
It is preferable that the addition amount of a silane coupling agent is 0.1-10 mass% with respect to a silicone resin. When the addition amount of the silane coupling agent is less than 0.1% by mass, the adhesion between the core material particles or conductive fine particles and the silicone resin is lowered, and the coating layer may fall off during long-term use. If it exceeds 10 mass%, toner filming may occur during long-term use.

  In the present invention, the coating layer has no film defects, and the average film thickness is preferably 0.05 to 3.00 μm. If the average film thickness is less than 0.05 μm, the coating layer is likely to be destroyed by use, and the film may be scraped. If the average film thickness exceeds 3.00 μm, the coating layer is not a magnetic substance, so that the carrier adheres to the image. May occur, and the resistance adjusting effect described later is not sufficiently exhibited.

  Moreover, it is preferable that a resin coating layer contains 50-500 weight part filler (electroconductive fine particle) with respect to 100 weight part of resin, and it is more preferable to contain 100-300 weight part filler. By containing a certain amount of filler 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. When the amount of filler is less than 50 parts by weight, the effect of preventing the coating layer from being scraped decreases. When the amount exceeds 500 parts, the proportion of the resin coming out on the carrier surface becomes relatively small, and the toner is spent on the carrier surface. As a result, resistance increases.

(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 less, the uneven shape as intended in the present invention cannot be obtained, and the shape becomes close to a true sphere, and the spent scraping effect cannot be obtained. When the core particle has an SF2 of 160 or more, the core material is exposed excessively when used in a developing machine for a long time in actual use, and the change in the initial resistance value and the resistance value after use becomes large. The amount of toner on the electrostatic latent image carrier and how it is mounted change, and the image quality becomes unstable.

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 is introduced into an image analysis apparatus (Luzex AP) manufactured by Nireco Corporation and analyzed, 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 Resolution 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 less than 32 μm, carrier adhesion may occur. When the volume average particle diameter exceeds 40 μm, the reproducibility of image details may be reduced and a fine image may not 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 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 occur due to scraping of the coating layer of the carrier, but 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. As a result, a stable image can be obtained for a very long 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 less than 2 parts by mass, the amount of replenishment carrier is excessive, the carrier is excessively supplied, and the carrier concentration in the developing device becomes too high, so that the charge amount of the developer tends to increase. Further, as the developer charge amount increases, the developing ability decreases and the image density decreases. On the other hand, if the amount exceeds 50 parts by mass, the carrier ratio in the replenishment developer decreases, so that the replacement of carriers in the image forming apparatus decreases, and the effect on carrier deterioration cannot be expected.

(Process cartridge)
The image forming method of the present invention uses the developer of the present invention to form an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier. Development to form a toner image, a step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and a step of fixing the toner image transferred to the recording medium.

FIG. 2 shows an example of the process cartridge of the present invention. The process cartridge (10) comprises a photoreceptor (11), a charging device (12) for charging the photoreceptor (11), and an electrostatic latent image formed on the photoreceptor (11) using the developer of the present invention. A developing device (13) for developing and forming a toner image and a cleaning device (after removing the toner remaining on the photoconductor (11) after transferring the toner image formed on the photoconductor (11) to a recording medium. 14) is integrally supported, and the process cartridge (10) is detachable from a main body of an image forming apparatus such as a copying machine or a printer.
Hereinafter, a method for forming an image using the image forming apparatus equipped with the process cartridge (10) will be described. First, the photosensitive member (11) is rotationally driven at a predetermined peripheral speed, and the charging device (12) uniformly charges the peripheral surface of the photosensitive member (11) to a predetermined positive or negative potential. Next, exposure light is irradiated onto the peripheral surface of the photoreceptor (11) from an exposure apparatus (not shown) such as a slit exposure type exposure apparatus or an exposure apparatus that performs scanning exposure with a laser beam, and electrostatic latent images are sequentially formed. The Further, the electrostatic latent image formed on the peripheral surface of the photoconductor (11) is developed by the developing device (13) using the developer of the present invention to form a toner image. Next, the toner image formed on the peripheral surface of the photoconductor (11) is synchronized with the rotation of the photoconductor (11), and the photoconductor (11) and the transfer device (not shown) are fed from the paper feed unit (not shown). ) Are sequentially transferred onto the transfer paper fed during (). Further, the transfer paper onto which the toner image has been transferred is separated from the peripheral surface of the photoreceptor (11), introduced into a fixing device (not shown) and fixed, and then copied as a copy (copy) of the image forming apparatus. Printed out. On the other hand, after the toner image is transferred, the surface of the photoconductor (11) is cleaned by the cleaning device (14) to remove the remaining toner, and then the charge is removed by a static eliminator (not shown). Used for image formation.

(Image forming device)
The image forming apparatus of the present invention includes an electrostatic latent image carrier, a charging unit that charges the latent image carrier, an exposure unit that forms an electrostatic latent image on the latent image carrier, and the electrostatic latent image. Developing means for developing the electrostatic latent image formed on the image carrier using a developer to form a toner image, and transferring the toner image formed on the electrostatic latent image carrier to a recording medium Transfer means, and fixing means for fixing the toner image transferred to the recording medium, and other means appropriately selected as necessary, for example, static elimination means, cleaning means, recycling means, control The developer of the present invention is used as a developer.

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. “Parts” represents parts by weight. In addition, Examples 1, 3, 4, 6, 7, 10, 11, and 14 to 21 are read as reference examples.

<Example of core material production>
[Core Material Production Example 1]
MnCO3, Mg (OH) 2, and Fe2O3 powder were weighed and mixed to obtain a mixed powder.
This mixed powder was calcined at 900 ° C. for 3 hours in an air atmosphere in a heating furnace, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 7 μm.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm. This granulated product was loaded into a firing furnace and fired at 1250 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles C1 having a volume average particle size of about 35 μm.
As a result of component analysis of this granulated product, MnO was 46.2 mol%, MgO was 0.7 mol%, and Fe2O3 was 53 mol%. Moreover, SF-2 at this time was 144, and Ra was 0.72 micrometer.

[Core material production example 2]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 1 μm.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1300 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles C2 having a volume average particle size of about 35 μm. Moreover, SF-2 at this time was 123, and Ra was 0.55 micrometer.

[Core Material Production Example 3]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 3 μm.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1200 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized by a pulverizer, and then the particle size was adjusted by sieving to obtain spherical ferrite particles C3 having a volume average particle size of about 35 μm. Moreover, SF-2 at this time was 152, and Ra was 0.94 micrometer.

[Core Material Production Example 4]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 0.8 μm.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1330 ° C. for 5 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles C4 having a volume average particle size of about 35 μm. At this time, SF-2 was 118, and Ra was 0.43 μm.

[Core Material Production Example 5]
The mixed powder was calcined in the same manner as in Core Material Production Example 1, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 4 μm.
This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 40 μm.
This granulated product was loaded into a firing furnace and fired at 1080 ° C. for 4 hours in a nitrogen atmosphere.
The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles C5 having a volume average particle size of about 35 μm. At this time, SF-2 was 165, and Ra was 1.03 μm.

<Examples of conductive fine particle production>
[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 wt% 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 having an average particle diameter of 570 nm.
The average particle size was measured using Nanotrac UPA-EX150 (manufactured by Nikkiso Co., Ltd.) in water at a material refractive index of 1.66 and a solvent refractive index of 1.33.

[Conductive fine particle production example 2]
Conductive fine particles P2 having an average particle size of 420 nm were obtained in the same manner as P1, except that 40 g of stannic chloride and 1.5 g of phosphorus pentoxide were added dropwise over 50 minutes in the preparation of conductive fine particle production example 1.

[Conductive fine particle production example 3]
Conductive fine particles P3 having an average particle size of 690 nm were obtained in the same manner as P1, except that 250 g of stannic chloride and 6.0 g of phosphorus pentoxide were added dropwise over 5 hours in the preparation of conductive fine particle production example 1.

[Conductive fine particle production example 4]
Conductive fine particles P4 having an average particle diameter of 570 nm were obtained in the same manner as P1, except that 135 g of stannic chloride and 1.5 g of phosphorus pentoxide were added dropwise over 2 hours and 40 minutes in the preparation of conductive fine particle production example 1. It was.

[Conductive fine particle production example 5]
Conductive fine particles P5 having an average particle size of 570 nm were obtained in the same manner as P1, except that 135 g of stannic chloride and 13.0 g of phosphorus pentoxide were added dropwise over 2 hours and 40 minutes in the preparation of conductive fine particle production example 1. It was.

[Conductive fine particle production example 6]
Conductive fine particles P6 having an average particle diameter of 570 nm were obtained in the same manner as P1, except that 135 g of stannic chloride and 0.9 g of phosphorus pentoxide were added dropwise over 2 hours and 40 minutes in the preparation of conductive fine particle production example 1. It was.

[Conductive fine particle production example 7]
Conductive fine particles P7 having an average particle diameter of 570 nm were obtained in the same manner as P1, except that 135 g of stannic chloride and 15.2 g of phosphorus pentoxide were added dropwise over 2 hours and 40 minutes in the preparation of conductive fine particle production example 1. It was.

[Conductive fine particle production example 8]
Exactly the same as P1 except that aluminum oxide was changed to aluminum oxide (HIT-70, manufactured by Sumitomo Chemical Co., Ltd.) and 14 g of stannic chloride and 0.5 g of phosphorus pentoxide were added dropwise over 20 minutes in the preparation of conductive fine particle production example 1. Thus, conductive fine particles P8 having an average particle diameter of 270 nm were obtained.

[Conductive fine particle production example 9]
In the adjustment of the conductive fine particle production example 1, aluminum oxide was changed to aluminum oxide (Taimicron TM-D, manufactured by Daimei Chemical Co., Ltd.), and P1 except that 5 g of stannic chloride and 0.2 g of phosphorus pentoxide were added dropwise over 6 minutes. In the same manner, conductive fine particles P9 having an average particle diameter of 190 nm were obtained.

[Conductive fine particle production example 10]
Exactly the same as P1 except that aluminum oxide was changed to aluminum oxide (Nippon Light Metals AHP200) and 280 g of stannic chloride and 7.5 g of phosphorus pentoxide were added dropwise over 5 hours and 30 minutes in the preparation of conductive fine particle production example 1. Thus, conductive fine particles P10 having an average particle size of 740 nm were obtained.

[Conductive fine particle production example 11]
Exactly the same as P1 except that aluminum oxide was changed to titanium oxide (KR-310 manufactured by Titanium Industry Co., Ltd.) and 150 g of stannic chloride and 3.0 g of phosphorus pentoxide were added dropwise over 3 hours. Thus, conductive fine particles P11 having an average particle diameter of 600 nm were obtained.

[Conductive fine particle production example 12]
Except for P1, except that aluminum oxide was changed to barium sulfate (B30 manufactured by Toshin Kasei Co., Ltd.) and 120 g of stannic chloride and 3.0 g of phosphorus pentoxide were added dropwise over 2 hours and 20 minutes. Similarly, conductive fine particles P12 having an average particle diameter of 560 nm were obtained.

[Conductive fine particle production example 13]
Conductive fine particles P13 having an average particle diameter of 570 nm were obtained in the same manner as P1, except that 135 g of stannic chloride and 4.0 g of sodium tungstate were dropped over 2 hours and 40 minutes in the preparation of conductive fine particle production example 13. It was.

[Conductive Fine Particle Production Example 14 (Conductive Fine Particle for Comparative Example)]
Conductive fine particles P14 having an average particle diameter of 400 nm were obtained in the same manner as P1, except that 30 g of stannic chloride and 0.8 g of phosphorus pentoxide were added dropwise over 35 minutes in the preparation of conductive fine particle production example 1.

[Conductive Fine Particle Production Example 15 (Conductive Fine Particle for Comparative Example)]
Conductive fine particles P15 having an average particle size of 720 nm were obtained in the same manner as P1, except that 285 g of stannic chloride and 5.0 g of phosphorus pentoxide were added dropwise over 5 hours and 40 minutes in the preparation of conductive fine particle production example 1. It was.

[Conductive Fine Particle Production Example 16 (Conductive Fine Particle for Comparative Example)]
Conductive fine particles P16 having an average particle diameter of 570 nm were obtained in the same manner as P1, except that phosphorus pentoxide was not added in the preparation of conductive fine particle production example 1.

[Conductive Fine Particle Production Example 17 (Conductive Fine Particle for Comparative Example)]
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 solution prepared by dissolving 11.6 g of stannic chloride in 1 liter of 2N hydrochloric acid and 12 wt% aqueous ammonia were added dropwise to the suspension over 40 minutes so that the pH of the suspension was 7-8. Subsequently, a solution obtained by dissolving 36.7 g of indium chloride and 5.4 g of stannic chloride in 450 ml of 2N hydrochloric acid and 12 wt% aqueous ammonia were added dropwise over 1 hour so that the pH of the suspension was 7-8. . 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 5 hours and 20 minutes to obtain conductive fine particles P17 having an average particle diameter of 360 nm.

[Conductive Fine Particle 18 (Conductive Fine Particle for Comparative Example)]
Tin oxide (Mitsui Metals Pastran-TYPE VI) is used as the conductive fine particles P18. The average particle size was 20 nm.

[Conductive Fine Particles 19 (Conductive Fine Particles for Comparative Example)]
Aluminum oxide (AKP-30 manufactured by Sumitomo Chemical) is used as the conductive fine particles P19. The average particle size was 300 nm.

[Conductive Fine Particle 20 (Conductive Fine Particle for Comparative Example)]
Carbon black (REGAL330 manufactured by Cabot Corporation) is used as the conductive fine particles 20. The average particle size was 25 nm.

  As mentioned above, the fluorescent X-ray analysis of the obtained electroconductive fine particles was implemented using ZSX-100E by Rigaku. The measurement was performed in EZ scan mode. The measurement results are shown in Table 1.

<Example of resin synthesis>
[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, 84.4 g (200 mmol: 3-methacryloxypropyltris (trimethylsiloxy) silane represented by CH2 = CMe-COO-C3H6-Si (OSiMe3) 3 (wherein Me is a methyl group). Silaplane TM-0701T / manufactured by Chisso Corporation), 39 g (150 mmol) of 3-methacryloxypropylmethyldiethoxysilane, 65.0 g (650 mmol) of methyl methacrylate, and 2,2′-azobis-2-methyl A mixture of 0.58 g (3 mmol) of butyronitrile 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 weight 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 weight of the resin R1 (solid content 25%) obtained in Resin Synthesis Example 1, 22 parts by weight of conductive fine particles P1, 2 parts by weight of titanium diisopropoxybis (ethyl acetoacetate) TC-750 (manufactured by Matsumoto Fine Chemical Co.) as a catalyst, SH6020 (manufactured by Toray Silicone Co.) as a silane coupling agent 0.3 A part by weight was diluted with toluene to obtain a resin solution having a solid content of 10 wt%. The resin solution was applied and dried on 1000 parts by weight of the core material C1 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.

[Carrier Production Example 2]
Carrier B was obtained in the same manner as in Carrier Production Example 1 except that P2 was used as the conductive fine particles.

[Carrier Production Example 3]
Carrier C was obtained in exactly the same manner as in Carrier Production Example 1 except that P3 was used as the conductive fine particles.

[Carrier Production Example 4]
Carrier D was obtained in the same manner as in Carrier Production Example 1 except that P4 was used as the conductive fine particles.

[Carrier Production Example 5]
Carrier E was obtained in exactly the same manner as in Carrier Production Example 1 except that P5 was used as the conductive fine particles.

[Carrier Production Example 6]
Carrier F was obtained in exactly the same manner as in Carrier Production Example 1 except that P6 was used as the conductive fine particles.

[Carrier Production Example 7]
Carrier G was obtained in exactly the same manner as Example 1 except that P7 was used as the conductive fine particles.

[Carrier Production Example 8]
Carrier production example 1 was obtained in exactly the same manner as in Example 1 except that P8 was used as the conductive fine particles.

[Carrier Production Example 9]
In Carrier Production Example 1, Carrier I was obtained in exactly the same manner except that P9 was used as the conductive fine particles.

[Carrier Production Example 10]
In Carrier Production Example 1, Carrier J was obtained in exactly the same manner except that P10 was used as the conductive fine particles.

[Carrier Production Example 11]
Carrier K was obtained in the same manner as in Carrier Production Example 1 except that P11 was used as the conductive fine particles.

[Carrier Production Example 12]
Carrier L was obtained in the same manner as in Carrier Production Example 1 except that P12 was used as the conductive fine particles.

[Carrier Production Example 13]
Carrier M was obtained in the same manner as in Carrier Production Example 1 except that P13 was used as the conductive fine particles.

[Carrier Production Example 14]
Carrier N was obtained in exactly the same manner as Example 1 except that 7 parts by weight of P1 was used as the conductive fine particles.

[Carrier Production Example 15]
Carrier production example 1 was obtained in exactly the same manner as in Example 1 except that 54.5 parts by weight of P1 was used as the conductive fine particles.

[Carrier Production Example 16]
Carrier production P was obtained in exactly the same manner as Example 1 except that 5 parts by weight of P1 was used as the conductive fine particles.

[Carrier Production Example 17]
In Carrier Production Example 1, Carrier Q was obtained in exactly the same manner except that 58.5 parts by weight of P1 was used as the conductive fine particles.

[Carrier Production Example 18]
In Carrier Production Example 1, Carrier R was obtained in exactly the same manner except that C2 was used as the core material.

[Carrier Production Example 19]
In Carrier Production Example 1, Carrier S was obtained in exactly the same manner except that C3 was used as the core material.

[Carrier Production Example 20]
In Carrier Production Example 1, Carrier T was obtained in exactly the same manner except that C4 was used as the core material.

[Carrier Production Example 21]
Carrier U was obtained in exactly the same manner as Example 1 except that C5 was used as the core material.

[Carrier Production Comparative Example 1]
Carrier a was obtained in exactly the same manner as Example 1 except that P14 was used as the conductive fine particles.

[Carrier Production Comparative Example 2]
Carrier b was obtained in the same manner as in Carrier Production Example 1 except that P15 was used as the conductive fine particles.

[Carrier Production Comparative Example 3]
Carrier c was obtained in exactly the same manner as Example 1 except that P16 was used as the conductive fine particles.

[Carrier Production Comparative Example 4]
Carrier d was obtained in the same manner as Example 1 except that P17 was used as the conductive fine particles.

[Carrier Production Comparative Example 5]
Carrier e was obtained in exactly the same manner as Example 1 except that P18 was used as the conductive fine particles.

[Carrier Production Comparative Example 6]
Carrier f was obtained in exactly the same manner as in Carrier Production Example 1 except that P19 was used as the conductive fine particles.

[Carrier Production Comparative Example 7]
Carrier g was obtained in the same manner as in Carrier Production Example 1 except that P20 was used as the conductive fine particles.

<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, stirrer, cooler and 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, stirrer, cooler and 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 Corporation) · · · 15 parts 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., to obtain [base toner A1].

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 U and a to g]
To the carriers A to U and a to g (93 parts) obtained in the carrier production example, 7.0 parts of the toner 1 (7.2 μm) obtained in the toner production example is added and stirred for 20 minutes by a ball mill. Thus, developers A to U and a to g were prepared.

(Evaluation)
<Evaluation of color mixing>
For the color stain evaluation method, each developer is set in a commercially available digital full-color printer (RICOH Pro C901, manufactured by Ricoh Co., Ltd.), and the development unit alone is stirred for 1 hour. The developer thus obtained is developed and fixed, and the L * 1, a * 1, and b * 1 values of the CIE color system at the location where the image density is 1.5 are obtained. On the other hand, in order to obtain an image free from color stains, an image formed with toner alone (including fixing) without being brought into contact with the carrier is prepared, and the CIE table of the portion where the image density is 1.5 as described above. The L * 0, a * 0, and b * 0 values of the color system are obtained.
The color difference ΔE between the two images obtained in this way is obtained by the following equation and used as a criterion.
ΔE = √ (L * 0−L * 1) 2+ (a * 0−a * 1) 2+ (b * 0−b * 1) 2
○: Good, Δ: Acceptable, ×: Unusable level for practical use ○ ΔE <2.0
△ 2.0 ≦ △ E ≦ 3.0
× △ E> 3.0

<Evaluation of initial edge carrier adhesion>
One of the important aims of the present invention is that the conductive fine particles have sufficient conductivity, and that the carrier using the conductive fine particles is adjusted to an appropriate resistance.
One of the methods for evaluating the aim is an evaluation of initial edge carrier adhesion. This is because the conductive fine particles have not obtained sufficient conductivity, and if the carrier has high resistance, the initial edge carrier adhesion deteriorates. When carrier adhesion occurs, it may cause damage to the photosensitive drum and the fixing roller, resulting in a decrease in image quality. Even if carrier adhesion occurs on the photoconductor, only a part of the carrier is transferred to the paper, and thus evaluation was made by the following method. Under the developing conditions of a charging potential (Vd) of −600 V, an exposure portion potential of −100 V, and a developing bias (Vb) of DC-400 V, that is, a background potential of 200 V, two dot lines (100 lpi) in the sub-scanning direction on the photoreceptor. / Inch) image was formed. Next, the two-dot line developed on the photoconductor was transferred with an adhesive tape (area 100 cm ² ), and the number of the dots was counted to evaluate the carrier adhesion.
The symbols described in the table are ◎: very good, ○: good, Δ: usable, x: defective (x is an unacceptable level).

<Durability evaluation>
A commercially available digital full-color printer (Ricoh Co., Ltd., IPSiO CX8200) (manufactured by Ricoh Co., Ltd., RICOH Pro C901) was set on each developer and evaluated for 100,000 sheets. The amount of spent toner, charge change, resistance change, edge carrier adhesion and solid carrier adhesion of the carrier were evaluated.

[(1) Evaluation of spent toner amount]
For the carrier printed with 100 kp and the initial carrier, the toner component is extracted with methyl ethyl ketone, and the difference is expressed as the spent toner amount (expressed in wt% with respect to the carrier weight).
◎: Very good, ◯: Good, △: Acceptable, ×: Unusable level ◎ 0 or more and less than 0.03 Wt% ○ 0.03 Wt% or more and less than 0.07 Wt% Δ 0.07 Wt% or more and 0 Less than 15 Wt% x 0.15 Wt% or more

[(2) Evaluation of change in charge amount after 100 kp]
The charge amount change (charge reduction amount) was determined by mixing a sample which was friction-charged by mixing 7% by mass of toner with respect to 93% by mass of the carrier before running, using a general blow-off method (TB-200, manufactured by Toshiba Chemical Corporation). ) Was subtracted from the charge amount (Q2) measured by the same method as in the above method, from the charge amount (Q1) measured in step 1). The amount. If the charge reduction amount is within 10.0 μc / g, there is no problem in practical use.

[(3) Evaluation of resistance change after 100 kp]
The static resistance of the carrier was measured using a 0 kp developer and a 100 kp printed developer. At this time, the toner was separated and removed using a blow-off device as a developer, and only the carrier was measured. The resistance value of the carrier was measured using the device shown in FIG. 1, ΔLogR was calculated, and the following determination was made.
◎: Very good, ○: Good, △: Acceptable, ×: Unusable level for practical use ◎ Δ LogR ≦ 0.5
○ 0.5 <△ LogR ≦ 1
△ 1 <△ LogR ≦ 2
× 2 <△ LogR
In addition, the cause of the resistance change is scraping of the binder resin film of the carrier, spent toner component, detachment of fine particles having a large particle size in the carrier coating film, etc., and the occurrence of these is evaluated by the resistance change amount. be able to.

[(4) Evaluation of edge carrier adhesion after 100 kp]
The edge carrier adhesion evaluation after 100 kp was performed in the same procedure as the above-mentioned initial edge carrier adhesion evaluation.

[(5) Evaluation of solid carrier adhesion after 100 kp]
When carrier adhesion occurs, it may cause damage to the photosensitive drum and the fixing roller, resulting in a decrease in image quality. Even if carrier adhesion occurs on the photoconductor, only a part of the carrier is transferred to the paper, and thus evaluation was made by the following method. A solid image (30 mm × 30 mm) of Ricoh Pro C901 under the above-mentioned development conditions (charge potential (Vd): −600 V, potential after exposure of a portion corresponding to an image portion (solid original): −100 V, development bias: DC-500 V) The number of carriers adhering to the toner was counted on the photoconductor to evaluate solid carrier adhesion. The symbols described in the table are ◎: very good, ○: good, Δ: usable, ×: poor.
The evaluation results are shown in Table 2 above.

  Various evaluation items were good for the developers shown in Examples 1 to 21. Also, there were no problems such as background contamination and in-machine contamination due to toner scattering. On the other hand, the developers of Comparative Examples 1, 4, 5, and 7 had a large resistance drop considered to be due to carrier film scraping over time, and the edge carrier adhesion after 100 kp was poor. The developer of Comparative Example 2 had a large increase in resistance with time, which was considered to be caused by the separation of the conductive fine particles from the coating film, and the solid carrier adhesion after 100 kp was poor. In addition, the developers of Comparative Examples 3 and 6 had high carrier resistance from the initial stage and poor edge carrier adhesion.

(About Figure 1)
1a Electrode 1b Electrode 2 Fluororesin 3 Carrier (About FIG. 2)
10 Process Cartridge 11 Photoconductor 12 Charging Device 13 Developing Device 14 Cleaning Device

Japanese Patent Laid-Open No. 55-127469 Japanese Patent Laid-Open No. 55-157751 JP-A-56-140358 JP-A-57-96355 JP 57-96356 A JP 58-207054 A JP-A-61-1110161 JP-A-62-273576 Japanese Unexamined Patent Publication No. 7-140723 JP-A-8-179570 JP-A-8-286429 Japanese Patent No. 4307352 JP 2006-79022 A JP 2008-262155 A JP 2009-186769 A JP 2009-251483 A

Claims (9)

A carrier for an electrostatic latent image developer comprising magnetic core material particles and a resin layer covering the surface thereof, wherein the resin layer contains conductive fine particles,
The conductive fine particle has a structure in which a conductive layer containing tin oxide is coated on a substrate containing at least a white inorganic pigment, and (tin peak intensity [kcps]) / The peak intensity ratio represented by (base element peak intensity [kcps]) is 1.5 to 12,
See contains one or more elements selected from phosphorus and tungsten in the conductive fine particles,
The peak intensity ratio represented by (peak intensity [kcps] of one or more elements selected from phosphorus and tungsten) / (tin peak intensity [kcps]) when the conductive fine particles are subjected to fluorescent X-ray analysis is 0 A carrier for an electrostatic latent image developer, characterized by being 0.033 to 0.100 . 2. The electrostatic latent image developer carrier according to claim 1, wherein the substrate of the conductive fine particles contains at least one selected from alumina and barium sulfate. The carrier for an electrostatic latent image developer according to claim 1, wherein the conductive fine particles contained in the resin layer have an average particle size of 200 to 700 nm. The carrier for an electrostatic latent image developer according to any one of claims 1 to 3, wherein the resin layer contains 50 to 500 parts by weight of conductive fine particles with respect to 100 parts by weight of the resin. The carrier for electrostatic latent image developer according to any one of claims 1 to 4, wherein the core material particles have SF-2 of 120 to 160 and Ra of 0.5 to 1.0 µm. A two-component developer comprising the electrostatic latent image developer carrier and toner according to claim 1. 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 The electrostatic latent image formed on the toner is developed using the two-component developer according to claim 6 to form a toner image, and a toner image formed on the electrostatic latent image carrier is obtained. An image forming apparatus comprising: a transfer unit that transfers to a recording medium; and a fixing unit that fixes a toner image transferred to the recording medium. The two-component development according to claim 6, wherein the electrostatic latent image carrier, a charging member that charges the surface of the electrostatic latent image carrier, and the electrostatic latent image formed on the electrostatic latent image carrier. A process cartridge comprising: a developing unit that develops using an agent; and a cleaning member that cleans the electrostatic latent image carrier. The step of forming an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier using the two-component developer according to claim 6. Developing to form a toner image; transferring the toner image formed on the electrostatic latent image carrier to a recording medium; fixing the toner image transferred to the recording medium; An image forming method comprising:

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