CN101295146A - Toner and developer for electrostatic image development and apparatus and equipment using them - Google Patents

Abstract

The invention provides a toner for electrostatic image development, a developing agent and apparatuses and devices using them. The toner contains a grinding agent which has 10-40% of sticking rate (A) expressed by following formula (1): Sticking rate (A)=B/(B+C)*100 [Formula (1)]; in the formula (1), B represents the weight of grinding agent adhered to the toner after applying ultrasonic vibration (an output of 60W, a frequency of 20kHz) for 15 minutes to a dispersion liquid with toner dispersed and removing the grinding agent floating on the surface of toner; C represents the weight of the removed grinding agent.

Description

Toner and developer for electrostatic image development and apparatus and equipment using them

technical field

The present invention relates to a toner for developing an electrostatic image, a method for producing the same, a developer for an electrostatic image, a toner cartridge, a process cartridge, and an image forming apparatus.

Background technique

In electrophotography, generally, an image is formed through a plurality of steps; an electrostatic latent image is electrically formed on the surface of a photoreceptor (latent image holder) using a photoconductive substance by various means, and an electrostatic latent image is formed by developing The formed electrostatic latent image is developed with an agent to form a toner image, and then the toner image is transferred (using an intermediate transfer body such as paper, if necessary) to the surface of a receiving material such as paper, and heated, Pressurization or both act together to fix the toner image. In addition, the toner remaining on the surface of the photoreceptor is removed through a cleaning step usually using a doctor blade.

During this cycle, contaminants such as untransferred toner, fogged toner, discharge products, and paper dust remain or adhere to the photoreceptor or intermediate transfer body; these can be removed by using a scraper or brush . On the other hand, a cleaning member such as a blade or a brush scrapes the photoreceptor or the intermediate transfer body; thus, from the standpoint of scratch resistance and abrasion resistance, it is necessary to maintain proper removal of contaminants from the photoreceptor surface and for a long period of time. The ability to consistently obtain high-quality images.

In order to improve scratch resistance and abrasion resistance, attempts have been made to add lubricating materials or abrasive materials to toners. For example, a method has been proposed (see Japanese Patent Application Laid-Open No. 2000-89502) in which a lubricant is added to a developer to form a film on a photoreceptor, thereby improving ease of cleaning and suppressing abrasion of the photoreceptor. Another method aimed at prolonging the life of the photoreceptor by providing a lubricant supply unit has also been proposed (for example, see Japanese Patent Laid-Open No. 2001-51571). In another method that has been proposed (for example, see Japanese Patent Laid-Open No. 2005-4051), untransferred toner is accumulated at the end of the blade and used as a lubricant supply unit to maintain ease of cleaning and prolong life (long-term stability). Another cleaning method proposed (see JP-A-2001-13837) provides a cleaning aid with a particle diameter smaller than that of toner at a contact portion of a photoreceptor contact cleaning blade with a width of 50 to 100 μm. agent to improve ease of cleaning. A method has further been proposed (see Japanese Patent Laid-Open No. 2005-115311 ) in which a mechanism for applying a protective agent to the surface of a photoreceptor is provided, thereby suppressing uneven wear of the photoreceptor and prolonging life.

Contents of the invention

The wear process of the latent image holder is as follows: First, the surface layer of the latent image holder is degraded by the discharge of the charging device, thereby increasing the surface roughness, and when the cleaning blade is pressed to the deteriorated position, the surface layer will be scratched. position, thus causing wear. At this time, toner, cleaning aids, and inorganic particles externally added to the toner are accumulated at the contact portion between the latent electrostatic image holder and the cleaning blade, and they affect the degree of abrasion and abrasion between positions Unevenness (unevenness of wear in the axial direction of the latent image holding body). In particular, the presence of high-hardness particles such as abrasives, which are harder than the surface of the latent image holding body, is an important factor affecting wear. In other words, it has been found that uniformly distributing the abrasive on the contact portion is effective in suppressing uneven wear.

However, abrasives conventionally added to toner exhibit strong adhesion to toner. Therefore, the abrasive is present in the area where the image is formed (image portion), but does not exist in the area where the image is not formed (non-image portion). As a result, the presence or absence of abrasive in the contact portion between the latent image holder and the cleaning device depends on the image pattern (image density) to be formed, and it is difficult to control the unevenness of abrasive distribution.

The present invention relates to providing a toner for developing an electrostatic image capable of effectively suppressing uneven wear of a latent image holder, a method for producing the toner, an electrostatic image developer containing the toner, a toner containing the toner A toner cartridge containing toner, a process cartridge accommodating the electrostatic image developer, and an image forming apparatus that can effectively suppress uneven wear of a latent image holder and can provide high-quality images.

The above-mentioned problems can be solved by the present invention as shown below.

A first aspect of the present invention provides a toner for developing an electrostatic image. The toner includes an abrasive having an adhesion rate (A) represented by the following formula (1) of 10% to 40%:

Adhesion rate (A)=B/(B+C)×100 Formula (1)

In formula (1), B represents applying ultrasonic vibration (output: 60 W, frequency: 20 kHz) for 15 minutes to the dispersion liquid in which the toner is dispersed and removing the abrasive particles floating on the surface of the toner. The weight of the abrasive attached to the toner after the toner, and C represents the weight of the abrasive removed above.

According to the first aspect, uneven wear of the latent image holding body can be effectively suppressed.

A second aspect of the present invention provides the toner for developing an electrostatic image according to the first aspect, wherein the adhesion rate (A) of the abrasive is 15% to 35%.

According to the second aspect, uneven wear of the latent image holding body can be more effectively suppressed.

A third aspect of the present invention provides the toner for developing an electrostatic image according to the first aspect, wherein the adhesion rate (A) of the abrasive is 20% to 30%.

According to the third aspect, uneven wear of the latent image holding body can be suppressed more effectively.

A fourth aspect of the present invention provides the electrostatic image developing toner according to any one of the first to third aspects, wherein the abrasive as described in the first aspect is cerium oxide or boron nitride, And the total amount of the grinding agent added is 0.5 wt% to 3 wt% based on the total toner components.

According to the fourth aspect, uneven wear of the latent image holding body can be effectively suppressed.

A fifth aspect of the present invention provides a method of producing a toner for electrostatic image development. The method includes adding an abrasive to the toner base particles when the toner base particles are loaded into a toner cartridge.

According to the fifth aspect, a toner for developing an electrostatic image capable of effectively suppressing uneven wear of a latent image holder can be easily produced.

A sixth aspect of the present invention provides the method for producing a toner for electrostatic image development as described in the fifth aspect, wherein the method further includes: after preparing the toner base particles and adding the Before the toner base particles are loaded into the toner cartridge, the grinding agent is added to the toner base particles, and wherein, the grinding agent is cerium oxide or boron nitride, and the The total amount of abrasive added is 0.5% by weight to 3% by weight based on the entire toner components.

According to the sixth aspect, a toner for developing an electrostatic image capable of effectively suppressing uneven wear of a latent image holder can be easily produced.

A seventh aspect of the present invention provides an electrostatic image developer. The developer includes at least a toner, and the toner is the toner for developing an electrostatic image according to any one of the first to fourth aspects.

According to the seventh aspect, uneven wear of the latent image holding body can be effectively suppressed.

An eighth aspect of the present invention provides a toner cartridge containing at least toner. The toner is the electrostatic image developing toner according to any one of the first to fourth aspects.

According to the eighth aspect, the toner for developing an electrostatic image capable of effectively suppressing uneven wear of the latent image holder can be easily supplied, thereby improving the maintenance of characteristics.

A ninth aspect of the present invention provides a process cartridge having at least a developer holder. The process cartridge houses the electrostatic image developer described in the seventh aspect.

According to the ninth aspect, an electrostatic image developer capable of effectively suppressing uneven wear of a latent image holder can be easily handled, and compatibility with image forming apparatuses of various configurations can be improved.

A tenth aspect of the present invention provides an image forming apparatus comprising: a latent image holder; a developing unit using the toner for developing an electrostatic image according to any one of the first to fourth aspects. an electrostatic latent image formed on the latent image holder into a toner image; a transfer unit that transfers the toner image formed on the latent image holder to a material to which a toner image can be transferred; and a cleaning unit that presses a cleaning blade against the latent image holder to remove untransferred residual components.

According to the tenth aspect, uneven wear of the latent image holder can be effectively suppressed, and thus a high-quality image can be obtained.

An eleventh aspect of the present invention provides the image forming apparatus according to the tenth aspect, wherein the untransferred residual component is accumulated at a contact portion between the latent image holder and the cleaning blade, and In the accumulated non-transfer residual components, the concentration of the abrasive is 5% by weight to 25% by weight.

According to the eleventh aspect, excessive wear of the latent image holder can be satisfactorily suppressed, and since it has excellent grinding ability, the ease of cleaning of the surface of the latent image holder can be improved, thereby achieving high-quality image formation .

A twelfth aspect of the present invention provides the image forming apparatus according to the eleventh aspect, wherein, in the accumulated untransferred residual components, the concentration of the abrasive is 6% by weight to 20% by weight.

According to the twelfth aspect, excessive wear of the latent image holder can be more effectively suppressed, and since it has more excellent grinding ability, the ease of cleaning of the surface of the latent image holder can be improved, thereby achieving high-quality image formation .

A thirteenth aspect of the present invention provides the image forming apparatus according to the eleventh aspect, wherein, in the accumulated non-transfer residual components, the concentration of the abrasive is 7% by weight to 15% by weight.

According to the thirteenth aspect, excessive wear of the latent image holder can be more effectively suppressed, and since it has more excellent grinding ability, the ease of cleaning of the surface of the latent image holder can be improved, thereby achieving high-quality image formation .

Description of drawings

This paper will describe in detail the exemplary embodiments of the present invention according to the following drawings, wherein:

FIG. 1 is a schematic configuration diagram showing an example of an image forming apparatus according to an aspect of the present invention;

FIG. 2 is an enlarged schematic view of a yellow unit in the imaging device shown in FIG. 1; and

Fig. 3 is a schematic configuration diagram showing an example of a process cartridge according to one aspect of the present invention.

Detailed ways

<Toner for electrostatic image development>

In the electrostatic image developing toner of the present invention, the adhesion rate (A) of the abrasive represented by the following formula (1) is 10% to 40%:

Adhesion rate (A)=B/(B+C)×100 Formula (1)

(In formula (1), B represents applying ultrasonic vibration (output: 60 W, frequency: 20 kHz) for 15 minutes to the dispersion liquid in which the toner is dispersed and removing all particles floating on the surface of the toner In the dispersion liquid, C represents the weight of the abrasive removed by the above process.)

The inventors consider that, in the toner for developing an electrostatic image (hereinafter simply referred to as "toner") having an abrasive adhesion rate within the above range, the ratio of the abrasive having strong adhesion is 10% to 40%. %, and abrasives with weak adhesion mostly exist on the surface of the toner. The abrasive with weak adhesion is in a floating state between the surface of the developing unit as the developing means and the surface of the latent image holder, and regardless of whether the surface portion to which the abrasive is attached is in the image portion or in the non-image portion, It will be attached to the surface of the latent image holder. During the transfer process, the abrasive adhering to the non-image portion is not transferred to the medium to which the toner image can be transferred, but reaches the contact portion between the cleaning blade and the latent image holder, and accumulates on the There; therefore, the uneven distribution of the abrasive can be satisfactorily suppressed, and is not affected by the image pattern to be formed.

In this specification, abrasives with weak adhesion will be referred to as "floating abrasives", and abrasives with strong adhesion will be referred to as "attaching abrasives". It can be confirmed that the abrasive is floating abrasive by observing whether or not the specific abrasive is removed from the surface of the toner while applying ultrasonic vibration (output: 60 W, frequency: 20 kHz) for 15 minutes to the dispersion liquid in which the toner is dispersed The agent is still attached to the abrasive.

"Method of Calculating Abrasive Adhesion Rate"

The method of calculating the adhesion rate (A) will be described in more detail below.

First, the toner is dispersed in the dispersion liquid. Then, under the conditions of output power of 60W and frequency of 20kHz, ultrasonic vibration was applied to the dispersion liquid for 15 minutes, the floating abrasive was removed from the surface of the toner and recovered, and the residual toner (floating grinding agent) in the dispersion liquid was (the toner to which the abrasive has been removed but the adhering abrasive is still attached) is filtered out. The abrasive content in the filtered toner can be obtained by measuring fluorescent X-rays characteristic of the abrasive. Specifically, a calibration curve is prepared in advance using samples whose toner and abrasive contents are known, and the amount of adhered abrasive (B) can be obtained from the fluorescent X-ray measurement of the filtered toner. In addition, the amount of the floating abrasive (C) can be obtained by measuring the weight of the floating abrasive removed and recovered by the above method. According to the formula (1), the adhesion rate (A) of the abrasive can be calculated.

As an ultrasonic vibration generator for applying ultrasonic vibration, Ultrasonic Generator Model US-300TCVP (trade name, manufactured by Nippon Seiki Co., Ltd.) was used. As the dispersion in which the electrostatic image developing toner was dispersed, 40 ml of an aqueous solution of a 0.2% by weight surfactant (polyoxyethylene octylphenyl ether, manufactured by Wako Pure Chemical Industries) was used. As an apparatus for measuring fluorescent X-rays, a fluorescent X-ray analyzer XRF1500 (trade name, manufactured by Shimadzu Corporation) was used. The measurement was performed under conditions of 40 kv and 70 mA using a rhodium (Rh) tube as an X-ray tube with an analysis time of 30 minutes.

All adhesion ratios (A) described in this specification are calculated values according to the above-mentioned method.

The adhesion rate of the abrasive in the toner is more preferably 15% to 35%, particularly preferably 20% to 30%.

A toner having an abrasive adhesion ratio within the above range can be produced according to the method for producing an electrostatic image developing toner described below.

<Method of producing toner for electrostatic image development>

The method for producing a toner for developing an electrostatic image according to an embodiment of the present invention includes an abrasive adding step of adding an abrasive to toner base particles when the toner base particles are loaded into a toner cartridge. In the case where the abrasive is added to the toner base particles when the toner base particles are loaded into the toner cartridge, the amount of floating abrasive in the toner can be controlled.

From the viewpoint of controlling the amount of adhering abrasive in the toner, in addition to the above-mentioned abrasive adding step, after preparing the toner base particles and before loading the toner base particles into a toner cartridge, The steps of adding and stirring the abrasive are performed. Hereinafter, the step of adding and stirring the abrasive after preparing the toner base particles and before loading the toner base particles into the toner cartridge is referred to as "the first abrasive adding step", and the The above-described step of adding the abrasive to the toner base particles when the toner base particles are loaded into the toner cartridge is referred to as the "second abrasive adding step".

The method of manufacturing the toner for developing an electrostatic image will be described in order of steps.

(1) Manufacture of toner base particles

The toner base particle is not particularly limited in terms of its production method. For example, mother particles produced by: a kneading pulverization method of kneading, pulverizing, and classifying a binder resin, a colorant, a release agent, and a charge control agent; A method of deforming particles obtained by the method; an emulsion polymerization coagulation method in which a dispersion liquid formed by emulsion polymerization of a polymerizable monomer for forming a binder resin is mixed with one or more of a colorant, a release agent and a charge control agent A plurality of dispersion liquid phases are mixed to be coagulated and heated and fused to obtain toner mother particles; a polymerizable monomer for forming a binder resin and one or more of a colorant, a release agent and a charge control agent a suspension polymerization method in which various solutions are suspended in an aqueous medium to perform polymerization; and a method in which one or more solutions of a binder resin and a colorant, a release agent, and a charge control agent are suspended in an aqueous medium to perform granulation Dissolution suspension method.

In addition, a known method such as a production method of further forming a coating layer on the toner base particle as a core obtained by the above method to form a core-shell structure can be used. However, from the viewpoint of controlling shape and particle size distribution, emulsion polymerization using an aqueous medium, emulsion polymerization coagulation method, and dissolution-suspension method are preferred, and emulsion polymerization coagulation method is particularly preferred.

The toner base particles contain a binder resin, a colorant, and the like, and may contain a release agent and/or a charge control agent if necessary. The volume average particle diameter thereof is preferably 2 to 12 μm, more preferably 3 to 9 μm.

The volume-average particle diameter (cumulative volume-average particle diameter) of the toner base particles is obtained by measuring the particle diameter distribution by MULTISIZER II (trade name, manufactured by Beckmann-Coulter Co., Ltd.), based on the measured Get the count in the particle size range (section) of each division, obtain the cumulative volume distribution curve from the small particle size side, take the particle size corresponding to the 50% point on the cumulative volume distribution curve as the volume average particle size .

The shape factor SF1 of the toner base particles is preferably 100-140, more preferably 125-140, from the viewpoint of obtaining high developability, transferability, and high image quality.

Here, the shape factor SF1 of the toner base particle refers to a value represented by the following formula (2).

SF1＝(ML ² /A)×(π/4)×100 Formula (2)

In the formula (2), SF1 represents the shape factor of the toner, ML represents the absolute maximum length of the toner base particles, and A represents the projected area of the toner base particles.

Here, the absolute maximum length of the toner base particle and the projected area of the toner base particle appearing in the formula (2) were obtained by using an optical microscope (trade name: MICROPHOTO-FXA, manufactured by Nikon Co., Ltd. Manufactured) toner particle images were taken at a magnification of 500 times, and the obtained image information was imported into an image analyzer (trade name: LUZEX III, manufactured by Nireco Corporation) through an interface for image analysis, thereby obtaining the obtained The absolute maximum length and projected area are stated. The shape factor SF1 can be obtained as an average value of data obtained by measuring randomly sampled 1000 toner base particles.

Each component used to manufacture the toner base particles will be described below.

binder resin

Examples of usable binder resins include homopolymers and copolymers of the following monomers: styrenes such as styrene and chlorostyrene; monoolefins such as ethylene, propylene, butene, and isoprene; such as vinyl acetate Vinyl esters such as vinyl propionate, vinyl benzoate and vinyl lactate; such as methyl acrylate, ethyl acrylate, butyl acrylate, lauryl acrylate, octyl acrylate, phenyl acrylate, methyl Alpha-methylene aliphatic monocarboxylates such as methyl acrylate, ethyl methacrylate, butyl methacrylate and lauryl methacrylate; such as vinyl methyl ether, vinyl ethyl ether and vinyl ethers such as vinyl butyl ether; and vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and vinyl isopropenyl ketone. Specific representative examples of the binder resin include polystyrene, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene Copolymers, styrene-maleic anhydride copolymers, polyethylene and polypropylene. Examples thereof also include polyesters, polyurethanes, epoxy resins, silicone resins, polyamides, modified rosins, and paraffin waxes.

Colorant

Typical examples of colorants include magnetic powder such as magnetite or ferrite, carbon black, aniline blue, Charcoil blue, chrome yellow, ultramarine blue, Dupont oil red, quinoline yellow, chloromethylene blue, phthalocyanine blue, oxalic acid Salt Malachite Green, Lamp Black, Rose Red, C.I. Pigment Red 48:1, C.I. Pigment Red 122, C.I. Pigment Red 57:1, C.I. Pigment Yellow 97, C.I. Pigment Yellow 17, C.I. Pigment Blue 15:1, and C.I. Pigment Blue 15:3.

The content of the colorant in the toner mother particle may be 1 to 30 parts by weight based on 100 parts by weight of the binder resin. In addition, surface-treated colorants may be used. It is also effective to use a pigment dispersant. Yellow toner, magenta toner, cyan toner, or black toner can be obtained by selecting the kind of colorant.

other ingredients

Typical examples of the release agent include low-molecular-weight polyethylene, low-molecular-weight polypropylene, Fischer-Tropsch wax, montan wax, carnauba wax, rice wax, and candelilla wax.

In addition, examples of internal additives include magnetic materials such as ferrite, magnetite, and the like, metals such as reduced iron, cobalt, nickel, and manganese, and alloys and compounds containing these metals.

A charge control agent may be added to toner base particles. As the charge control agent, known charge control agents can be used, and azo-based metal complexes, salicylic acid metal complexes, and polar group-containing resin-type charge control agents can also be used. The toner may be a magnetic toner containing a magnetic material inside or a non-magnetic toner not containing a magnetic material.

(2) The first abrasive addition step

In the method of producing the toner, the first abrasive adding step may be performed from the viewpoint of controlling the amount of the attached abrasive. In the first abrasive adding step, the abrasive is added and mixed after the toner mother particles are produced and before the toner mother particles are loaded into a toner cartridge.

As the abrasive to be added (externally added) to the toner, common abrasives can be used. Examples include cerium oxide, strontium titanate, magnesium oxide, aluminum oxide, silicon carbide, zinc oxide, silicon dioxide, titanium oxide, boron nitride, calcium pyrophosphate, zirconium oxide, barium titanate, calcium titanate, or calcium carbonate of inorganic particles. In addition, composite materials of these inorganic substances can be used. Among the abrasive particles, cerium oxide is preferred.

Abrasive particles can be treated with reagents such as: Titanium coupling agents such as tetrabutyl titanate, tetraoctyl titanate, isopropyl triisostearyl titanate, tris(decylbenzenesulfonyl) titanate Isopropyl ester or bis(dioctyl pyrophosphate) glycolate titanate; or silane coupling agent, such as γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl )aminopropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxy Silane hydrochloride, hexamethyldisilazane, methyltrimethoxysilane, butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltriethoxysilane, octyltrimethoxysilane, Decyltrimethoxysilane, dodecyltrimethoxysilane, phenyltrimethoxysilane, o-methylphenyltrimethoxysilane or p-methylphenyltrimethoxysilane. In addition, hydrophobization treatment can be performed by using higher fatty acid metal salts such as silicone oil, aluminum stearate, zinc stearate, or calcium stearate.

Abrasive particles may be subjected to treatments such as heating, pulverization, or classification before being mixed with toner base particles.

As for the particle size of the abrasive particles, the number average primary particle size is preferably 0.1 μm to 3 μm, more preferably 0.3 μm to 1 μm, particularly preferably 0.5 μm to 0.8 μm.

The number average primary particle diameter can be measured by the following method. The abrasive particles externally added to the toner were observed with a scanning electron microscope (trade name: SEM: S-4700, manufactured by Hitachi, Ltd.) at 100 fields of view (magnification: 50000 times). The particle diameter (the average value of the longer diameter and the shorter diameter obtained by approximating the particle image to a circle) of the circular particle corresponding to the image area of each abrasive particle was measured at 1000 points to measure The average value of the results was taken as the number average primary particle diameter of the abrasive particles.

The particle size (number-average primary particle size) of the abrasive particles described in this specification is calculated according to the above-mentioned method.

In the first abrasive addition step, the addition and mixing of the abrasive may be performed using a known mixer such as a V-blender, Henschel mixer, or Redige mixer.

In addition, at this time, various other additives may be added. Examples of such additives include cleaning aids such as fluidizing agents, polystyrene particles, polymethylmethacrylate particles, or polyvinylidene fluoride particles, and transfer aids.

As a method of mixing the abrasive with the toner base particles, the abrasive particles may be mixed with the toner base particles alone, or the abrasive particles and other additives may be added to the toner base particles and mixed together, or previously Abrasive particles are added to toner base particles and mixed before adding other additives and mixed, or other external additives are previously added to toner base particles and mixed before adding abrasive particles and mixed. A sieving step may be performed after said mixing.

(3) The second grinding agent addition step

In the method for producing toner, from the viewpoint of controlling the amount of floating abrasive, a second abrasive adding step is performed in which the ground agent added.

As the abrasive used in the second abrasive adding step, the abrasive usable in the first abrasive adding step can be used in the second abrasive adding step.

In the second grinding agent adding step, the grinding agent can be added to the toner mother particles by the following methods: one of the methods, a predetermined amount of grinding agent is dropped into the toner particle funnel from the grinding agent adding device, The funnel is configured on the upper part of the loading device for loading the toner mother particles into the toner box; or in the second method, the abrasive input port is configured to be used for loading the toner mother particles into the toner cartridge. The loading port of the toner cartridge is arranged side by side, so that the toner base particles are loaded into the toner cartridge and at the same time, a predetermined amount of abrasive is directly put into the toner cartridge from the abrasive inlet.

When the toner is loaded into a toner cartridge together with a carrier for forming a two-component developer, the developer may be loaded into the toner after mixing the toner base particles with the carrier to prepare a developer The second abrasive addition step for adding abrasive is carried out while the cartridge is in use.

From the first abrasive addition step to the second abrasive addition step, the total amount of the abrasive added is preferably 0.5% by weight to 3% by weight based on the entire toner components, more preferably 0.6% by weight to 2.5% by weight %, particularly preferably 0.7% by weight to 2.0% by weight.

When carrying out the first abrasive addition step, based on the viewpoint of controlling the amount of the attached abrasive and the amount of the floating abrasive within a favorable range, the amount of the abrasive added in the first abrasive addition step is the same as that in the second abrasive addition step. The ratio of the amount of abrasive added in the middle (addition amount in the first abrasive addition step: addition amount in the second abrasive addition step) is preferably 1:1 to 1:4, more preferably 1:1 to 1: 2.

<Electrostatic Image Developer>

The electrostatic image developing toner may be used directly as a one-component developer or in the form of a two-component developer. When this toner is used as a two-component developer, the toner is used in admixture with a carrier, and, as described above, the toner manufacturing method is carried out after mixing the toner with the carrier The second abrasive addition step in .

The carrier usable in the two-component developer is not particularly limited, and known carriers can be selected. Examples thereof include iron oxide, magnetic metals such as nickel and cobalt, magnetic oxides such as ferrite and magnetite, resin-coated carriers having a resin-coated layer on the surface of a core material, and magnetic dispersion-type carriers. The carrier may be a resin-dispersed carrier in which a conductive material is dispersed in a matrix resin.

Examples of coating or matrix resins used in this carrier include, but are not limited to: polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyethylene Base ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer, pure silicone resin containing organosiloxane bond or its modified product, fluorinated resin, polyester, polycarbonate Esters, phenolic and epoxy resins.

Examples of conductive materials include, but are not limited to, metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, barium sulfate, aluminum borate, potassium titanate, and tin oxide.

In addition, examples of the core material of the carrier include magnetic metals such as iron, nickel and cobalt, magnetic oxides such as ferrite and magnetite, and glass beads. When the carrier is used in the magnetic brush method, a magnetic material is preferred. The volume average particle diameter of the core material of the carrier is usually 10 to 500 μm, preferably 30 to 100 μm.

The surface of the core material of the carrier can be coated with a resin by, for example, a method involving coating the surface of the core material with a solution for coating layer formation containing a coating resin dissolved in a suitable solvent and various additives. The solvent is not particularly limited, and the solvent can be selected in consideration of the type of coating resin to be used and coating suitability.

Examples of specific resin coating methods include a dipping method of dipping a carrier core material in a solution for forming a coating layer, a spraying method of spraying a solution for forming a coating layer onto the surface of a carrier core material, spraying a solution for forming a coating layer onto a subsequent A fluidized bed method on a carrier core material floated by flowing air, and a kneader coater method in which a carrier core material and a coating layer forming solution are mixed in a kneader coater and then the solvent is removed.

In addition, a coating film can be formed by mixing and attaching a particulate coating resin and additives to a carrier core material, followed by heat treatment or high shear treatment.

The mixing ratio (weight ratio) of the toner and the carrier in the two-component developer is preferably "toner: carrier = 1:100 to 30:100", more preferably "toner: carrier = 3:100 to 20:100".

<imaging device>

The image forming apparatus will be described below.

An image forming apparatus according to an aspect of the present invention includes: a latent image holder; a developing unit that develops an electrostatic latent image formed on the latent image holder with toner to form a toner image; a transfer unit that transfers a toner image formed on a latent image holder to a material to which the toner image can be transferred; and a cleaning unit that presses a cleaning blade against The latent image holder is used to remove untransferred residual components, and the toner is the above-mentioned toner for electrostatic image development.

In the image forming apparatus, untransferred residual components are accumulated at the contact portion between the latent image holder and the cleaning blade, and in the accumulated untransferred residual components (hereinafter simply referred to as "deposited components"), The concentration of the abrasive is preferably 5% by weight to 25% by weight, more preferably 6% by weight to 20% by weight, particularly preferably 7% by weight to 15% by weight.

By controlling the total amount of abrasive added in the toner used in the image forming apparatus and the attachment rate of the abrasive (that is, by controlling the amount of the attached abrasive and the amount of the floating abrasive), the abrasive in the toner can be While controlling the additive amount of the abrasive within an appropriate range, the concentration of the abrasive in the bulk component is controlled within the above range.

Specifically, the following formula (3) can be considered to control the total amount of abrasive added in the toner and the attachment rate of the abrasive:

(a)＝{(b)+(c)}/{(d)+(c)}×100 Formula (3)

a: Concentration of abrasive in bulk components (% by weight)

b: Amount of abrasive contained in non-transfer residual component in image portion=(average image portion area (m ² ))×(toner developed amount per unit area in image portion (g/m ² )) ×(total concentration of abrasive added to toner (% by weight)/100)×(adhesion rate of abrasive (%)/100)×(100-transfer efficiency (%))/100

c: Amount of abrasive adhering to the non-image portion =

(Average area of non-image area (m ² ))×(Abrasive deposition amount per unit area of non-image area (g/m ² ))

d: Amount of untransferred residual components in the image portion =

(average image portion area (m ² ))×(toner development amount per unit area in image portion (g/m ² ))×(100−transfer efficiency (%))/100

"Toner development amount per unit area in image portion", "transfer efficiency" and "abrasive adhesion amount per unit area in non-image portion" can be measured according to the following methods, respectively.

Measurement of toner development amount per unit area in image portion

A developed image capable of forming an image pattern of a solid image having a predetermined area is formed on the latent image holding body, and the operation of the image forming apparatus is forcibly stopped immediately before the developed image is processed by the transfer step. The developed image on the latent image holder was transferred to a belt whose area was known, and the weight was measured to find the amount of development per unit area.

Measurement of transfer efficiency

A developed image forming an image pattern of a solid image having a predetermined area is formed on the latent image holder, and the operation of the image forming apparatus is forcibly stopped immediately after the developed image has undergone the transfer step. The remaining untransferred toner on the portion where the developed image was transferred was transferred onto a belt of known area, and its weight was measured. The obtained weight was divided by the amount of toner developed per unit area in the image portion to obtain the transfer efficiency.

Measurement of abrasive deposition amount per unit area in non-image area

A non-image pattern is formed on the latent image holder. The imaging device is then forcibly shut down. The non-image portion was transferred onto a tape whose area was known, and the weight was measured to obtain the abrasive adhesion amount per unit area.

The amount of abrasive adhered per unit area in the non-image portion and the amount of abrasive contained in untransferred residual components in the image portion can be controlled by controlling the total amount of abrasive added in the toner and the adhesion rate of the abrasive.

In other words, the abrasive concentration in the accumulation component can be controlled by controlling the total amount of abrasive added in the toner and the adhesion rate of the abrasive in consideration of the following three factors: (i) the average area of the image portion and the non-image portion The average area (ie average image density), (ii) transfer efficiency, (iii) the amount of toner developed per unit area.

"Measurement Method of Abrasive Concentration in Bulk Composition"

The method of measuring the abrasive concentration in the accumulation component in an actual image forming apparatus will be described below.

Abrasive concentration can be obtained by measuring abrasive-specific fluorescent X-rays. Specifically, a calibration curve is prepared using samples whose toner concentration and abrasive concentration are known. Then, the accumulated components accumulated in the contact portion between the cleaning blade and the latent image holder were sampled. This concentration can be obtained from fluorescent X-ray measurements of the sample. Since the amount of build-up components is practically small, a sufficient amount for fluorescent X-ray measurements can be ensured by printing 500 pages of images with an average image density of 10%, sampling the build-up components at the contacts, and repeating these steps 5-10 Second-rate.

As an apparatus used for the fluorescent X-ray measurement, a fluorescent X-ray analyzer (trade name: XRF1500, manufactured by Shimadzu Corporation) was used. The measurements were carried out under conditions of 40 kv and 70 mA using a rhodium tube as an X-ray tube with an analysis time of 30 minutes.

The abrasive concentration in the bulk components described in this specification is all measured according to the above method.

In the image forming apparatus, for example, a portion containing a developing unit may have a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus body. This process cartridge may be a process cartridge including at least a developer holder and containing an electrostatic image developer.

An example of an image forming apparatus will be described below with reference to the drawings. However, the imaging device is not limited thereto. Hereinafter, main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

FIG. 1 is a schematic diagram showing the composition of a four-tandem full-color imaging device. The image forming apparatus shown in FIG. 1 includes first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming devices) that output yellow (Y), yellow (Y), Images of each color of magenta (M), cyan (C), and black (K). These imaging units (hereinafter simply referred to as “units”) 10Y, 10M, 10C, and 10K are arranged in parallel in the horizontal direction at predetermined intervals. The units 10Y, 10M, 10C, and 10K may be process cartridges that can be attached to and detached from the image forming apparatus body.

An intermediate transfer belt 20 as an intermediate transfer body is provided above each of the units 10Y, 10M, 10C, and 10K (according to the direction of the drawing) so as to extend through each unit. The intermediate transfer belt 20 is provided so as to be wound on a drive roller 22 and a backup roller 24 which are in contact with the inner surface of the intermediate transfer belt 20 and are arranged from left to right in the drawing. are spaced apart from each other in the direction. The intermediate transfer belt 20 is arranged to run in a direction from the first unit 10Y to the fourth unit 10K. The backup roller 24 is urged by a spring or the like (not shown) in a direction away from the drive roller 22 to apply a predetermined tension to the intermediate transfer belt 20 wound around the backup roller 24 and the drive roller 22 . In addition, an intermediate transfer body cleaning device 30 is provided on the surface of the intermediate transfer belt 20 on the latent image holder side so as to face the driving roller 22 .

Four-color (yellow, magenta, cyan, and black) toners contained in each of the toner cartridges 8Y, 8M, 8C, and 8K can be supplied to the developing devices (developing unit ) in 4Y, 4M, 4C and 4K.

The first to fourth units 10Y, 10M, 10C, and 10K have the same configuration, so the yellow image-forming first unit 10Y disposed upstream in the traveling direction of the intermediate transfer belt will be described as their representative. In parts equivalent to the first unit 10Y, reference numerals attached to magenta (M), cyan (C), or black (K) are substituted for yellow (Y), thereby omitting references to the second to fourth units 10M, 10M, Instructions for 10C and 10K.

The first unit 10Y has a photoreceptor 1Y as a latent image holder. Around the photoreceptor 1Y, a charging roller 2Y for charging the surface of the photoreceptor 1Y with a predetermined potential, and an exposure device 3 for exposing the charged surface with a laser beam 3Y according to a color separation image signal to form an electrostatic latent image are provided in this order. , a developing device (developing unit) 4Y that supplies charged toner to the electrostatic latent image to develop the electrostatic latent image, and a primary transfer that transfers the developed toner image to the intermediate transfer belt 20 A printing roller (primary transfer unit) 5Y and a photoreceptor cleaning device (cleaning unit) 6Y that removes residual toner on the surface of the photoreceptor 1Y after the primary transfer.

The primary transfer roller 5Y is arranged inside the intermediate transfer belt 20 , and the primary transfer roller 5Y is arranged at a position facing the photoreceptor 1Y. Bias power sources (not shown in the figure) that apply a primary transfer bias are connected to the primary transfer rollers 5Y, 5M, 5C, and 5K, respectively. The respective bias power sources change the transfer bias applied to the respective primary transfer rollers by a control section (not shown in the figure).

The operation of forming a yellow image in the first unit 10Y will be described below. First, before operation, the charging roller 2Y charges the surface of the photoreceptor 1Y until it reaches a potential of about -600V to -800V.

Photoreceptor 1Y includes a conductive substrate (volume resistivity at 20°C: 1×10 ⁻⁶ Ωcm or less) and a photosensitive layer provided on the conductive substrate. The photosensitive layer usually has very high electrical resistance (similar electrical resistance to ordinary resins). However, when irradiated with the laser beam 3Y, the specific resistance of the portion irradiated with the laser beam will change. Therefore, the laser beam 3Y is emitted to the surface of the charged photoreceptor 1Y by the exposure device 3 according to the yellow image data transmitted from the control section (not shown in the drawing). The photosensitive layer on the surface of the photoreceptor 1Y is irradiated with the laser beam 3Y, whereby an electrostatic latent image of a yellow print pattern is formed on the surface of the photoreceptor 1Y.

The electrostatic latent image is an image formed on the surface of the photoreceptor 1Y by charging, and this electrostatic latent image is the said negative latent image, which is formed as follows: the specific resistance of the irradiated portion of the photosensitive layer is lowered by the laser beam 3 , so that the charged charge on the surface of the photoreceptor 1Y flows; and the charge on the portion not irradiated by the laser beam 3 remains, thereby forming the negative latent image.

The electrostatic latent image thus formed on the surface of the photoreceptor 1Y is moved to a predetermined development position by the rotation of the photoreceptor 1Y. At this developing position, the electrostatic latent image on the photoreceptor 1Y is visualized (developed) by the developing device 4Y.

The developing device 4Y accommodates a yellow toner containing, for example, toner mother particles containing a yellow colorant, an attached abrasive, and a floating abrasive. The toner base particles in the yellow toner are charged by friction when stirred inside the developing device 4Y. Due to the agitation in the developing device 4Y, the floating abrasive and the toner base particles are well agitated and mixed. The frictionally charged toner base particles have the same electric charge (negative polarity) as the charge on the photoreceptor 1Y, and are held on the developer roller (developer holder). When the surface of the photoreceptor 1Y passes the developing device 4Y, the toner mother particles are electrostatically attached to the charge-neutralized latent image portion on the surface of the photoreceptor 1Y, thereby developing the latent image. At this time, since the adhering abrasive in the yellow toner strongly adheres to the toner base particles, the adhering abrasive moves to the latent image portion along with the electrostatic movement of the toner base particles to the latent image portion. (i.e. the image section). On the other hand, the floating abrasive exists in a floating state in a region between the surface of the developer roller (developer holder) and the surface of the photoreceptor 1Y, and moves due to the centrifugal force of the developer roller and adheres to the non-latent image portion (non-image part).

The subsequent movement of the toner base particles, attached abrasive, and floating abrasive attached to the surface of the photoreceptor 1Y will be described in detail with reference to FIG. 2 in which the image forming unit 10Y in FIG. 1 is enlargedly shown.

As shown in FIG. 2 , the yellow toner base particles 40Y to which the attached abrasive is attached adhere to the latent image portion (image portion) on the photoreceptor 1Y, and the floating abrasive 42Y adheres to the image portion on the photoreceptor 1Y. and non-image parts. The photoreceptor 1Y is then rotated at a predetermined speed in the direction indicated by arrow mark A, and the image portion and the non-image portion are conveyed to a predetermined primary transfer position. At the primary transfer position, a predetermined primary transfer bias is applied to the primary transfer roller 5Y, thereby applying an electrostatic force directed from the photoreceptor 1Y to the primary transfer roller 5Y to the yellow toner to which the attached abrasive is adhered. Mother particle 40Y. As a result, the toner image (toner mother particles and attached abrasive) on the photoreceptor 1Y is transferred to the intermediate transfer belt 20 . The transfer bias applied at this time has a (+) polarity opposite to that of the toner (−). For example, the transfer bias voltage of the first unit 10Y is controlled to about +10 μA by a control section (not shown in the figure). On the other hand, the floating abrasive 42Y attached to the image portion and the non-image portion is not affected by the electrostatic force generated by the primary transfer bias of the primary transfer roller 5Y, and most of the floating abrasive remains on the photoreceptor 1Y onto the intermediate transfer belt 20 without being transferred.

The remaining toner base particles 40Y to which the attached abrasive adhered and the remaining floating abrasive 42Y remaining on the photoreceptor 1Y are removed and recovered by the cleaning device 6Y. At this time, untransferred residual components such as the remaining toner base particles 40Y to which the abrasive is attached and the remaining floating abrasive 42Y are partially deposited on the cleaning blade 60Y and the photoreceptor 1Y in the cleaning device 6Y. Contact parts that come into contact with each other. In this image forming apparatus, by controlling the addition amount and adhesion rate of the abrasive in the electrostatic image developing toner suitable for the developing device 4Y, the amount of the abrasive in the accumulated non-transfer residual component (accumulation component) 44Y is reduced. The concentration is controlled at 5% by weight to 25% by weight.

The primary transfer biases applied to the primary transfer rollers 5M, 5C, and 5K arranged after the second unit 10M are also controlled in the same manner as the first unit.

The intermediate transfer belt 20 having the yellow toner image thus transferred by the first unit 10Y is conveyed sequentially through the second to fourth units 10M, 10C, and 10K so that the respective color toner images are superimposed to achieve multiple transfer .

The four-color toner images multi-transferred by the first to fourth units on the intermediate transfer belt 20 reach the intermediate transfer belt 20 , the support roller 24 in contact with the inner surface of the intermediate transfer belt 20 and the A secondary transfer portion of a secondary transfer roller (secondary transfer unit) 26 on the image holding surface side of the transfer belt 20 . On the other hand, the recording paper (the medium on which the image can be transferred) P is supplied by the supply mechanism to the gap between the secondary transfer roller 26 and the intermediate transfer belt 20 which are in pressure contact with each other at predetermined timing, and the predetermined The secondary transfer bias voltage of is applied to the secondary transfer roller 26 . The transfer bias voltage applied at this time has (+) polarity opposite to the polarity (-) of the toner; therefore, the electrostatic force directed from the intermediate transfer belt 20 to the recording paper P acts on the toner image, thereby The toner image on the intermediate transfer belt 20 is transferred to the recording paper P. As shown in FIG. The secondary transfer bias at this time is determined based on the resistance detected by a resistance detection unit (not shown) that detects the resistance of the secondary transfer portion, and is controlled by a voltage.

After that, the recording paper P is conveyed to a fixing device (fixing unit) 28 where the toner image is heated to melt and fix the superimposed toner image on the recording paper P. The recording paper P after the color image fixing is completed is conveyed to the discharge section, whereby a series of color image forming operations is completed. On the other hand, the surface of the intermediate transfer belt 20 on which the toner image has been transferred is cleaned by the intermediate transfer body cleaning device 30 .

The image forming apparatus described above has a configuration in which a toner image is transferred to recording paper P via an intermediate transfer belt 20 . However, the configuration is not limited thereto, and another configuration in which the toner image is directly transferred from the photoreceptor to the recording paper may be employed.

<Process Cartridge, Toner Cartridge>

Fig. 3 is a schematic diagram showing the constitution of a preferred example of a process cartridge containing the electrostatic image developer according to an aspect of the present invention. The process cartridge 200 includes: a charging roller 108 clockwise in the drawing, a developing device 111 , and a photoreceptor cleaning device (cleaning unit) 113 on the outer peripheral surface of the photoreceptor 107 . The process cartridge 200 has an opening portion 118 and an opening portion 117 combined and integrated by the mounting rail 116 . The opening 118 is used to expose the surface of the photoreceptor 107 located downstream of the charging roller 108 (downstream in the driving direction of the photoreceptor 107 ) and upstream of the developing device 111 . The opening portion 117 is used to expose the surface of the photoreceptor 107 on the downstream side of the photoreceptor cleaning device 113 and on the upstream side of the charging roller 108 to neutralize the charges (discharge exposure).

The process cartridge 200 is attachable to and detachable from the body of the image forming apparatus including the transfer device 112, the fixing device 115 and other constituent parts (not shown in the drawings). The process cartridge 200 constitutes an image forming apparatus together with the image forming apparatus body. Reference numeral 300 denotes recording paper.

The process cartridge 200 shown in FIG. 3 includes a charging device 108 , a developing device 111 , a cleaning device (cleaning unit) 113 , an opening 118 for exposure, and an opening 117 for neutralizing exposure. However, these means can be selectively combined. In other words, the process cartridge may have a photosensitive body 107 and at least A component. The process cartridge 200 may have a toner cartridge (not shown in the figure), and may also have a toner conveying device (not shown in the figure) that conveys replenished toner from the toner cartridge to the developing device 111 .

The toner cartridge according to one aspect of the present invention will be described below. The toner cartridge is attachable to and detachable from the image forming apparatus. The toner cartridge contains toner supplyable to a developing unit disposed in an image forming apparatus, and the toner is the above-mentioned toner. The toner cartridge contains at least toner, and depending on the mechanism of the image forming apparatus, may contain, for example, a developer composed of toner and a carrier.

The image forming apparatus shown in FIG. 1 is an image forming apparatus having a constitution in which toner cartridges 8Y, 8M, 8C, and 8K can be attached and detached, and developing devices 4Y, 4M, 4C, and 4K are supplied via toner supply pipes (not shown). Out) to the toner cartridge corresponding to each developing unit (color). When the amount of toner contained in the toner cartridge becomes low, the cartridge can be replaced.

Example

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples. Hereinafter, unless otherwise specified, "part" means "part by weight", and "%" means "% by weight".

<Manufacture of toner base particles (A)>

(Preparation of resin particle dispersion (A))

A resin particle dispersion (A) was prepared by the method described below using the following components.

·Styrene 375 parts

· 25 parts of n-butyl acrylate

· Acrylic 5 parts

·Dodecylmercaptan 30 parts

A solution is prepared by mixing and dissolving the above-mentioned raw materials. This solution was added to a solution containing 8 parts of nonionic surfactant (trade name: NONIPOLE400, manufactured by Sanyo Chemical Industry Co., Ltd.) and 9 parts of anionic surfactant (trade name: NEOGENSC, manufactured by No. Ichi Kogyo Pharmaceutical Co., Ltd.) flask, and make it carry out emulsion polymerization. After slowly mixing this emulsion for 30 minutes, 50 parts of ion-exchanged water in which 5 parts of ammonium persulfate was dissolved was added. After nitrogen replacement, while stirring in the flask, the contents of the flask were heated to 80° C. in an oil bath, and emulsion polymerization was continued in this state for 4 hours. As a result, a resin particle dispersion (A) in which resin particles having a volume average particle diameter of 132 nm, a Tg of 61° C., and a weight average molecular weight Mw of 11,200 were dispersed was obtained.

(Preparation of Colorant Dispersion (A))

A colorant dispersion liquid (A) was prepared by the method described below using the following ingredients.

·Magenta pigment (C.I. Pigment Red 57) 55 parts

・Nonionic surfactant (NONIPOLE 400, manufactured by Sanyo Chemical Co., Ltd.) 4 parts

·Ion-exchanged water 240 parts

The above-mentioned raw materials were mixed and dissolved, then stirred in a homogenizer (trade name: ULTRA TURAXT50, manufactured by IKA Corporation) for 40 minutes, and then applied a dispersion treatment with a disperser (altimizer), thereby making a dispersion having an average particle diameter of 220 nm. Colorant dispersion (A) of colorant particles.

(Preparation of release agent dispersion)

A release agent dispersion (A) was prepared by the method described below using the following ingredients.

Paraffin wax (trade name: HNP-190, manufactured by Nippon Seikasha Co., Ltd., melting point: 85° C.)

95 copies

· Cationic surfactant (trade name: SANISOL B50, manufactured by Kao Co., Ltd.) 5 parts

·Ion-exchanged water 240 parts

The above raw materials were dispersed in a round stainless steel flask for 30 minutes using a homogenizer (trade name: ULTRA TURAX T50, manufactured by IKA Corporation). This dispersion was then subjected to a dispersion treatment with a pressure discharge type homogenizer to prepare a release agent dispersion (A) in which release agent particles having a volume average particle diameter of 520 nm were dispersed.

(Preparation of Toner Mother Particles (A))

Toner mother particles (A) were prepared by the method described below using the following ingredients.

·Resin particle dispersion (A) 245 parts

·Colorant dispersion (A) 20 parts

·Anti-sticking agent dispersion (A) 45 parts

· Polyaluminum hydroxide (trade name: PAHO2S, manufactured by Asada Chemical Co., Ltd.) 0.8 parts

·Ion-exchanged water 800 parts

The above-mentioned components were mixed and dispersed in a round stainless steel flask using a homogenizer (trade name: ULTRA TURAX T50, manufactured by IKA Corporation). To agglomerate the particles, the contents of the flask were heated to 45° C. in a heating oil bath with stirring and held at this temperature for 30 minutes. The temperature of the heating oil bath was then further raised to 59°C and held at this temperature for 60 minutes. The size of the particles in the slurry was measured, and the volume average particle diameter D50 was 5.6 μm. After that, in order to control the shape of the aggregated particles, 1N sodium hydroxide was added to this slurry containing the aggregated particles so that the pH of the system was controlled at 7.2, and the flask was sealed and heated to 85° C. under continuous stirring using a magnetic seal. , and maintain this temperature for 5 hours. After cooling, the toner mother particles were filtered out, washed four times with ion-exchange water, and freeze-dried to obtain toner mother particles (A).

(1) Using an image forming apparatus DOCU CENTER COLOR 400 (trade name, manufactured by Fuji Xerox Co., Ltd.) (used under the following conditions: the transfer efficiency is 95%, the amount of toner development per unit area of the image portion is 4.5 g/ m ² , the average image density of the image to be formed is 10%) for the following evaluations.

<Comparative example 1>

(first abrasive addition step)

First, an abrasive (cerium oxide: number-average primary particle diameter: 0.5 μm) was added to the toner base particle (A) obtained above in an amount (addition concentration in the final toner) shown in Table 1 below, It was then mixed for 20 minutes at a peripheral speed of 25 m/s in a 5 L Henschel mixer as a stirrer. Coarse particles in the resulting mixture were removed with a 45 μm mesh sieve.

(second abrasive addition step)

In addition, as the second addition of the abrasive, the toner base particle (A) and the abrasive (cerium oxide: number average primary particle diameter 0.5 μm) into the toner cartridge.

The method of loading the toner base particles (A) and the abrasive into the toner cartridge, which have been subjected to the first abrasive adding step, may be a method comprising the steps of: injecting a predetermined amount of abrasive from the abrasive input device into the toner cartridge. A toner particle hopper disposed on an upper portion of a loader for loading toner mother particles into a toner cartridge.

"Measurement and calculation of various physical properties"

For the toner obtained up to the second abrasive addition step, the "abrasive adhesion rate" was calculated according to the method described above. Furthermore, the toner cartridge was loaded into an image forming apparatus (trade name: DOCUCENTRE COLOR 400), and the "abrasive adhesion amount per unit area in the non-image portion" was measured according to the above method, and based on the "abrasive adhesion amount per unit area in the non-image portion". The "abrasive adhesion amount" in the formula (3) is used to calculate the "abrasive concentration in the accumulation component". In addition, the "abrasive concentration in the deposited components" actually deposited at the contact portion between the cleaning blade and the photoreceptor was measured according to the method described above.

<Examples 1 to 11 and Comparative Examples 2 and 3>

In a similar manner to the method described in Comparative Example 1, the developer was loaded into the toner cartridge and measured and calculate the physical properties.

The measurement and calculation results are shown in Table 1 below.

"evaluate"

Average wear rate of photoreceptor

The average wear speed (nm/thousand cycles) of the photoreceptor was measured according to the following method.

The film thickness of the unused photoreceptor and the film thickness of the photoreceptor after printing for 1200 thousand cycles were measured. From the measured values, the degree of reduction in the film thickness of the photoreceptor due to abrasion was calculated. The average wear rate (nm/thousand cycles) was calculated from the reduction in film thickness. An average wear rate below 5 nm/thousand cycles is acceptable, while an average wear rate exceeding 5 nm/thousand cycles is unacceptable.

uneven wear

Uneven wear (maximum wear value - minimum wear value) (nm/thousand cycles) was measured according to the following method.

In the measurement of the film thickness of the photoreceptor when not in use and the film thickness of the photoreceptor after 1200 thousand cycles of printing in the calculation of the average wear speed of the photoreceptor, the uneven wear value (that is, the wear value) is calculated from the maximum wear value and the minimum wear value The difference between the maximum point and the minimum wear point). A non-uniform wear value below 2 nm/thousand cycles is acceptable, while a non-uniform wear value exceeding 2 nm/thousand cycles is unacceptable.

The measurement results are shown in Table 2 below.

Table 2

<Measurement result>Abrasive concentration in bulk composition (weight %) The average wear rate of the photoreceptor (nm/thousand cycles) Uneven wear (nano/thousand cycles) Comparative example 1 0.07% 6.3 6.0 Comparative example 2 4.9% 2.2 2.2 Example 1 5.3% 2.2 1.8 Example 2 6.0% 2.9 1.4 Example 3 6.5% 3.1 1.3 Example 4 6.7% 3.6 0.8 Example 5 7.8% 3.5 1.3 Example 6 15.9% 3.8 1.3 Example 7 10.1% 3.7 1.4 Example 8 14.9% 3.7 1.7 Example 9 18.7% 4.5 1.6 Example 10 21.3% 4.5 0.2 Example 11 24.6% 4.9 1.7 Comparative example 3 27.0% 6.0 2.1

(2) Using an image forming apparatus DOCU CENTER COLOR F450 (trade name, manufactured by Fuji Xerox Co., Ltd.) (used under the following conditions: transfer efficiency 93%, toner development amount per unit area in the image portion 5.0 g /m ² , the average image density of the image to be formed is 30%) for the following evaluations.

<Examples 12 and 13 and Comparative Examples 4 and 5>

Except that the abrasive used in the first abrasive addition step and the second abrasive addition step is changed to boron nitride (number-average primary particle size: 0.3 μm) and the abrasive addition amount in each abrasive addition step is changed to the following table 3, the developer was loaded into the toner cartridge according to the method described in Comparative Example 1 and various physical properties were measured and calculated.

Claims (13)

1. A toner for electrostatic image development, the toner comprising an abrasive having an adhesion rate (A) represented by the following formula (1) of 10% to 40%: Adhesion rate (A)=B/(B+C)×100 Formula (1) In the formula (1), B represents applying ultrasonic vibration with an output power of 60 W and a frequency of 20 kHz to the dispersion liquid in which the toner is dispersed for 15 minutes and removing the abrasive particles floating on the surface of the toner. The weight of the abrasive attached to the toner after the toner, and C represents the weight of the abrasive removed above. 2. The toner for electrostatic image development according to claim 1, wherein the adhesion rate (A) of the abrasive is 15% to 35%. 3. The toner for developing an electrostatic image according to claim 1, wherein the adhesion rate (A) of the abrasive is 20% to 30%. 4. The electrostatic image developing toner according to claim 1, wherein the abrasive is cerium oxide or boron nitride, and the total amount of the abrasive added is 0.5 wt. % to 3% by weight. 5. A method of manufacturing a toner for electrostatic image development, the method comprising the steps of: When the toner base particles are loaded into a toner cartridge, abrasives are added to the toner base particles. 6. The method for producing a toner for developing an electrostatic image according to claim 5, wherein the method further comprises the step of: after preparing the toner mother particle and after preparing the toner mother particle Before loading the toner cartridge, the grinding agent is added to the toner mother particles, and, wherein the grinding agent is cerium oxide or boron nitride, and the total addition of the grinding agent The amount is 0.5% by weight to 3% by weight based on the entire toner components. 7. An electrostatic image developer comprising at least a toner, and the toner is the toner for developing an electrostatic image according to any one of claims 1 to 4. 8. A toner cartridge containing at least a toner, the toner being the toner for developing an electrostatic image according to any one of claims 1 to 4. 9. A process cartridge having at least a developer holder, the process cartridge containing the electrostatic image developer according to claim 7. 10. An imaging device comprising: latent image holder; a developing unit for developing the electrostatic latent image formed on the latent image holder into a toner image using the toner for developing an electrostatic image according to any one of claims 1 to 4; a transfer unit that transfers the toner image formed on the latent image holder to a material to which the toner image can be transferred; and A cleaning unit that presses a cleaning blade against the latent image holder to remove untransferred residual components. 11. The image forming apparatus according to claim 10, wherein said untransferred residual components are accumulated at a contact portion between said latent image holder and said cleaning blade, and In the transfer residual components, the concentration of the abrasive is 5% by weight to 25% by weight. 12. The image forming apparatus according to claim 11, wherein the abrasive has a concentration of 6% by weight to 20% by weight in the accumulated non-transfer residual component. 13. The image forming apparatus according to claim 11, wherein the abrasive has a concentration of 7% by weight to 15% by weight in the accumulated non-transfer residual components.

Images