Abstract: In an electrophotographic developer and a process for forming an image, an electrophotographic toner used therein contains spherical toner parent particles and two or more kinds of inorganic particles having different average particle diameters, at least one kind of the inorganic fine particles being spherical particles having an average primary particle diameter of about 80 to 300 nm, and the inorganic particles containing the spherical particles being attached to the toner parent particles to provide a structure satisfying the following conditions (1) and (2):

Abstract: A toner for developing an electrostatic image is disclosed. The arithmetic average of shape coefficient SF-1 of the toner particles calculated by Equation 1 is from 125 to 170 and a ratio of that to an arithmetic average of the shape coefficient SF-2 of the toner particles calculated by Equation 2, SF-1/SF-2, is from 1.10 to 1.52 and the ratio of the toner particles having a circle corresponding diameter measured by a flow particle image analyzer of from not less than 0.60 to less than 1.00 &mgr;m is not more than 5.0% in number. The image forming methods employing the toner are also disclosed.

Abstract: An electrostatic image developing toner is disclosed. The toner has a domain-matrix structure; the average of the horizontal FERE diameter of the part corresponding to said domain is from 200 to 900 nm; and the variation coefficient of said horizontal FERE diameter is 40 percent or less.

Abstract: In an image forming method, when viewed from the moving direction of a photosensitive body 1, there is disposed, on the upstream side, a first developing roller 61 opposed to and adjacent to the photosensitive body 1 and rotatable in the opposite direction to the photosensitive body 1, while the peripheral speed ratio of the roller 61 to the photosensitive body 1 ranges from 0.8 to 2.0; on the downstream side of the roller 61, there is disposed a second developing roller 62 rotatable in the same direction to the photosensitive body 1, while the peripheral speed ratio of the roller 62 to the photosensitive body 1 ranges from 1.05 to 2.0; and the shape coefficient SF1 of the toners of two-component developing agent ranges from 120 to 170, while the shape coefficient SF2 ranges from 110 to 130.

Abstract: A toner is formed of toner particles each comprising a binder resin and iron oxide particles dispersed therein. The toner particles are characterized by uniform but non-surface-exposed dispersion of the iron oxide particles within the toner particles as represented by (i) a carbon content (A) and an iron content (B) giving a ratio B/A<0.001 at surfaces of the toner particles as measured by X-ray photoelectron spectroscopy, (ii) an average circularity of at least 0.970, and (iii) at least 50% by number of toner particles satisfying D/C≦0.02, wherein C denotes a projection area-equivalent circular diameter of each toner particle and D denotes a minimum distance of iron oxide particles from a surface of the toner particle, based on a sectional view of the toner particle as observed through a transmission electron microscope (TEM).

Abstract: A magnetic toner for developing an electrostatic latent image has magnetic toner particles containing at least a binder resin, a magnetic powder and a wax component. The magnetic powder has magnetic iron oxide particles the particle surfaces of which have been coat-treated with an organic surface modifying agent. The magnetic iron oxide particles contain silicon element (Si) in an amount of from 0.4 to 2.0% by weight based on the weight of iron element (Fe) and the magnetic iron oxide particles have an Fe/Si atomic ratio of from 1.0 to 4.0 at their outermost surfaces. The magnetic toner particles have shape factors SF-1 and SF-2 as measured by an image analyzer, with a value of SF-1 of from 100 to 160, a value of SF-2 of from 100 to 140 and a value of (SF-2)/(SF-1) of not more than 1.0.

Abstract: A toner for developing an electrostatic latent image contains a binder resin, a colorant, a wax, and inorganic fine particles. The toner contains the inorganic fine particles content in the range from 1 to 10% by weight, the temperature at which the complex viscosity &eegr;° of the toner in the case of measuring at a frequency of 100 rad/second shows 1000 Pa.s ranges from 125 to 145° C., and the temperature at which the complex viscosity &eegr;° of the toner in the case of measuring at a frequency of 100 rad/second shows 100 Pa.s ranges from 180 to 210° C.

Abstract: A toner for developing an electrostatic image excellent in fixing property and particularly in light transmissibility and coloring property and satisfying high image quality and high reliability, and a process for producing the same, as well as a developer for an electrostatic image and a process for forming an image are provided. The toner for developing an electrostatic image contains at least a resin component and colorant particles, and the colorant particles exhibit a dispersion state inside the toner observed by a transmission electron microscope. The dispersion state satisfies two conditions, where (1) the colorant particles have a dispersion average particle diameter of 100 nm or less, and (2) the colorant particles have a content of coarse particles of a diameter of 400 nm or more 5% by number or less of the total of the colorant particles.

Abstract: An electrophotographic developer is provided that attains improvement in reliability by improvement in cleaning property and reduction in wear of a photoreceptor in a well-balanced manner without impairing high transfer efficiency and high image quality of a spherical toner.

Abstract: In an image forming system, an image-bearing member having a photoconductor layer comprising an Si-based non-single crystal material is charged at a relatively low potential of 250 to 600 volts by a contact charging member in the presence of electroconductive fine powder. An electrostatic latent image formed on the image-bearing member is developed with a magnetic toner which includes magnetic toner particles comprising at least a binder resin and a magnetic iron oxide, and inorganic fine powder and electroconductive fine powder present at the surface of the magnetic toner particles. The magnetic toner has a weight-average particle size of 3-10 &mgr;m and an average circularity of 0.950 to 0.995, and contains 0.05 to 3.00 % of isolated iron-containing particles.

Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;cm or more.

Abstract: A method of forming a toner image is disclosed. The photoreceptor is installed so that the center axis of the cylinder is to be almost horizontal, front edge of the cleaning blade is pressed against surface of the photoreceptor at the top, radio of width of the photosensitive layer of the photoreceptor to length of the cylindrical electroconductive substrate is 80/100 to 99/100, and a number ratio of toner particles having a shape coefficient of 1.2 to 1.6 is at least 65 percent in the toner particles.

Abstract: A toner including toner particles including at least a binder resin having a first melting point and a first solubility parameter, a colorant and a particulate release agent having a second melting point lower than the first melting point and a second solubility parameter different from the first solubility parameter, wherein the particulate release agent dispersed in the toner particles has an average needle-shape degree LD/SD of not less than 1.6, where LD is a diameter of a particle of the release agent dispersed in the toner in a major axis direction thereof and SD is a diameter of the particle in a minor axis direction.

Abstract: In an image forming method including the steps of: developing an latent image on an image forming body employing a developer of composed of flattened spheroidal toner particles; transferring the formed toner image onto a transfer material; and fixing the toner image on the transfer material, the flattened spheroidal toner particles satisfy the following conditions: r2/r1 falls within the range of 0.6 to 1.0; d/r2 falls within the range of 0.1 to 0.5; r2 is in the range of 5 &mgr;m to 20 &mgr;m; and r1 falls within the range of 5 &mgr;m to 20 &mgr;m, where r1 represents an average length of a major axis of each of the flattened toner particles, r2 represents an average length of a minor axis of each of the flattened toner particles, and d represents an average thickness of each of the flattened toner particles.

Abstract: An image forming toner is provided, including at least:

Abstract: A toner exhibiting good balance of low-temperature fixability, an anti-offset characteristic and a developing performance in continuous image formation is formed of at least a binder resin, a colorant and a wax. The toner exhibits a dielectric loss tangent showing a maximum of 6.0×10−2 to 10.0×10−2 in a temperature range of 90 to 125° C. The toner provides a DSC curve showing at least one heat-absorption peak or shoulder in a temperature range of 85 to 140° C. on temperature increase according to differential scanning calorimetry (DSC). The binder resin comprises a hybrid resin having a vinyl polymer unit and a polyester unit.

Abstract: A toner is proposed which includes toner particles and a fluidity-imparting agent and have such characteristics that the toner particles has an average circularity of 0.93 to 0.97, and that a residue of the toner is in an amount of 10 mg or less when 100 g of the toner is sieved with a 500-mesh sieve, which toner is for use in an electrophotographic image formation method using an intermediate image transfer method. A full-color image formation method, using this toner, and an image formation apparatus in which this toner is used are also proposed.

Abstract: Provided by the present invention are (1) a dry toner excellent in powder flowability and transferability when formed as a small-particle-size toner; (2) a dry toner excellent in any one of heat storage stability, low-temperature fixing property and anti-hot offset property; (3) a dry toner excellent in gloss exhibition when an image is formed by a full color copying machine; and (4) a dry toner which does not need application of an oil to a heat roll. Described specifically, provided by the present invention is a dry toner comprising a toner binder and a colorant, wherein the toner has a Wadell's practical sphericity ranging from 0.90 to 1.00, the toner binder contains a high-molecular-weight condensation resin (A) and a low-molecular-weight condensation resin (B), a ratio (MnA/MnB) of the number average molecular weight (MnA) of the resin (A) to the number average molecular weight (MnB) of the resin (B) is at least 1.

Abstract: In a fixing method for fixing a toner image to a transfer medium, heat-and-pressure fixing is carried out using a specific pressure member and a specific toner. The pressure member has a heat-resistant elastic layer having a thermal conductivity of 0.20 W/m·K or below. The toner has, in its DSC endothermic curve, at least a maximum value in the region of temperature of from 105° C. to 150° C., and, in GPC of THF-soluble component of the toner, a main peak in the region of molecular weight of from 2,000 to 25,000, a sub-peak or shoulder in the region of molecular weight of 70,000 or higher, and an Mw/Mn ratio of 8 or higher, containing 20% to 70% of a component belonging to the region of molecular weight of from 1,000 to 10,000.

Abstract: A toner has toner particles containing at least a binder resin, a colorant and a sulfur-containing compound selected from the group consisting of a sulfur-containing polymer and a sulfur-containing copolymer. The toner has a weight-average particle diameter of from 5 &mgr;m to 12 &mgr;m, and the toner has, in its particles of 3 &mgr;m or larger in diameter, at least 90% by number of particles with a circularity of 0.900 or higher, and has a specific relationship between the cut rate Z and the toner weight-average particle diameter X and a specific relationship between the number-based cumulative value Y of particles with a circularity of 0.950 or higher and the toner weight-average particle diameter X. Also disclosed are an image-forming method and a process cartridge which make use of the toner.

Abstract: A toner for developing an electrostatic latent image, a process for producing the same, and a developer for developing an electrostatic latent image using the same are provided, in which the toner flowability, the charging property, the developing property, the transferring property and the fixing property are simultaneously satisfied in a long period of time. The toner for developing an electrostatic latent image comprising a colored particles containing a binder resin, a coloring agent and a releasing agent, and an external additive, the external additive containing a monodisperse spherical inorganic oxide having a true specific gravity of from 1.3 to 1.9 and a volume average particle diameter of from 80 to 300 nm. It is preferred that the inorganic oxide is silica, the colored particles have a shape coefficient of 125 or less, and the external additive further contains a reaction product of metatitanic acid and a coupling agent, which has an electric resistance of 1010 &OHgr;·cm or more.

Abstract: An electrophotographic toner excellent in coloring property, fixing property, OHP transmittance and charging property, a process for producing the same, and a two-component developer are provided. The electrophotographic toner contains at least a binder resin, a colorant, a releasing agent and inorganic fine particles, in which the toner has a conglobation degree of about from 100 to 130, the releasing agent has an average particle diameter of about from 0.1 to 1 &mgr;m, a ratio of a major axis and a minor axis of about from 1.1 to 10, and the inorganic particles are dispersed in the toner particles.

Abstract: A dry magnetic toner is formed of magnetic toner particles comprising a binder resin and magnetic iron oxide particles. The magnetic toner is provided with excellent developing performances and transferability by controlling the presence of isolated iron-containing particles and containing a high percentage of spherical particles, the amount of which is controlled relative to the weight-average particle size of the magnetic toner and a content of particles of 3 &mgr;m or below in the magnetic toner.

Abstract: A toner for developing an electrostatic image, a process for producing the same, a developer for developing an electrostatic image and a process for forming an image are disclosed. The toner contains a resin, a colorant and a releasing agent, in which the toner has protrusions having a height of about from 0.05 to 2 &mgr;m, a part of the protrusions encompasses the releasing agent, and a proportion of elements derived from the releasing agent is about 10% by atom or less based on elements on a surface of the toner that is quantitatively determined by X-ray photoelectron spectroscopy.

Abstract: A toner is provided for the development of an electrostatic image which includes an agglomerate of particles obtained by agglomerating at least primary polymer particles and primary colorant particles, wherein the toner has a THF insoluble contentof from 15% to 80% and the toner further includes a wax having a melting point of 30 to 100° C., and the method for producing the same.

Abstract: A toner for developing an electrostatic image comprising a resin, a colorant and a releasing agent in which the toner particles are obtained by salting out/fusion-adhering a resin particle comprising a binding resin and a releasing agent together with a colorant particle is disclosed. The toner comprises the toner particles having a variation coefficient of not more than 16% and a number variation coefficient of the number particle size distribution of not more than 27%.

Abstract: The present invention provides a toner comprising a binder resin, a colorant, and a releasing agent wherein the releasing agent has an endothermic starting temperature of 40° C. or more and a melting point of 120° C. or less which are measured using a differential scanning calorimeter, the binder resin contains a linear resin and a non-linear resin, the content of the releasing agent existing at the surface of toner particles is 0 to 30% by weight, and the shape factor MLS2 of the toner particles is from 100 to 130. Preferably a mixture of a linear Polyester and a non linear polyester is used as the binder resin. Preferably the weight average molecular weight of the linear polyester is 2.0×103 to 5.0×104. The toner of the present invention has excellent developing characteristics and transfer characteristics, and superior offset resistance even in an oil-less fixing system.

Abstract: The present invention provides a process for the preparation of a novel toner satisfying a high resolution, a low temperature fixability and a high offset resistance at a low cost. A novel toner for the development of an electrostatic image is provided comprising an agglomerate of particles containing at least primary polymer particles, wherein said primary polymer particles substantially comprise a wax encapsulated therein.

Abstract: A magnetic toner includes: magnetic toner particles each comprising at least a binder resin and magnetic toner, and inorganic fine powder. The magnetic toner has an average circularity of at least 0.970, and a magnetization of 10-50 Am2/kg at a magnetic field of 79.6 kA/m. The magnetic powder comprises at least magnetic iron oxide. The magnetic toner particles retain carbon in an amount of A and iron in an amount of B at surfaces thereof as measured by X-ray photoelectron spectroscopy, satisfying: B/A<0.001. The binder resin comprises a resin formed by polymerization of a monomer comprising at least styrene monomer. The magnetic toner has a residual styrene monomer content of less than 300 ppm, and contains at least 50% by number of toner particles satisfying a relationship of: D/C≦0.

Abstract: A toner suitable for use in electrophotography, etc., is composed of toner particles each containing a binder resin, a colorant and a wax component. Each toner particle has such a microtexture as to provide a cross section as observed through a transmission electron microscope (TEM) exhibiting a matrix of the binder resin, a particle of the wax enclosed with the matrix; and the binder resin dispersed in a particulate form in the wax particle, and the toner particles have a residual monomer content of at most 500 ppm by weight of the toner particles. The colorant may also be dispersed in the wax particle enclosed within the matrix of the binder resin.

Abstract: A toner for developing a static image having excellent charging characteristics and transferring characteristics, a process for producing the toner, a developer for a static image using the toner, and a process for producing an image are provided. A toner for developing a static image including at least a binder resin and a coloring agent, having an external additive adhered on a surface thereof, the toner having an average volume particle diameter D50 of about from 3.0 to 8.0 &mgr;m, an average volume particle diameter distribution index GSDv of about 1.26 or less, and a surface property index expressed by the following equations of about 6.

Abstract: An electrophotographic image forming method employing a photoreceptor is disclosed. The decrease &Dgr;Hd (in &mgr;m), in layer thickness per rotation in wear test of the organic electrophotographic photoreceptor defined in the specification, is in the range of 0≦&Dgr;Hd<1×10−5, and a toner used in said development process is one which is obtained by suspension-polymerizing a polymerizable composition consisting of at least a polymerizable monomer and a colorant in a water based medium or one which is obtained by fusing resinous particles in a water based medium.

Abstract: A toner including a binder resin; a colorant; and an external additive, wherein the external additive includes a particulate inorganic material, and a silicone oil, wherein the silicone oil is present on the particulate inorganic material in an amount of Ws by weight and present as a free silicone oil in an amount of Wfs by weight, and a free silicone degree defined as a ratio Wfs/Ws is from 10 to 70%.

Abstract: A toner comprising a toner binder and a colorant, composed of resin particles produced by causing an extension reaction and/or crosslinking reaction of a dispersion formed of a reactive group-containing prepolymer (&agr;) contained in an aqueous medium with an extension agent and/or a crosslinking agent (&bgr;). The toner has a Wadell practical sphericity of 0.90 to 1.00 and is superior in fluidity, transferability, the storage stability under heat, low temperature fixing ability and hot offset resistance.

Abstract: A toner is proposed which includes toner particles and a fluidity-imparting agent and have such characteristics that the toner particles has an average circularity of 0.93 to 0.97, and that a residue of the toner is in an amount of 10 mg or less when 100 g of the toner is sieved with a 500-mesh sieve, which toner is for use in an electrophotographic image formation method using an intermediate image transfer method. A full-color image formation method, using this toner, and an image formation apparatus in which this toner is used are also proposed.

Abstract: A toner suitable for use in electrophotography, etc., is composed of toner particles each containing a binder resin, a colorant and a wax component. The toner has a number-average particle size of 2-6 &mgr;m and a standard deviation in particle size of below 2.6 based on a number-basis distribution of circle-equivalent diameters, an average circularity of 0.970-0.995 and a standard deviation in circularity of below 0.030 based on a circularity frequency distribution, and a residual monomer content of at most 500 ppm. The toner particles have such a microtexture as to provide a particle cross section as observed through a transmission electron microscope (TEM) exhibiting a matrix of the binder resin and a particle of the wax dispersed in a discrete form in the matrix of the binder resin.

Abstract: The present invention provides a toner-set comprising yellow toner, magenta toner, cyan toner and black toner, in which

Abstract: A developer for developing an electrostatic latent image is formed from toner particles each comprising a binder resin and a colorant, inorganic fine powder having a number-average particle size of 4-80 nm based on primary particles, and electroconductive fine powder. The developer is characterized by having a number-basis particle size distribution in the range of 0.60-159.21 &mgr;m including 15-60% by number of particles in the range of 1.00-2.00 &mgr;m, and 15-70% by number of particles in the range of 3.00-8.96 &mgr;m, each particle size range including its lower limit and excluding its upper limit. As a result of inclusion an appropriate amount of the electroconductive fine powder represented by the particle size fraction of 1.00-2.

Abstract: An electrophotographic photoreceptor is disclosed. The photoreceptor has a difference in ionization potential between the photosensitive layer and the hardenable resinous layer of not more than 0.4 eV, and a response time T10 defined in the specification is not more than 0.25 second. An image forming method and apparatus employing the photoreceptor are also disclosed.

Abstract: A magnetic toner comprising magnetic toner particles containing at least a binder resin, a magnetic material containing a magnetic ion oxide, and a release agent. The magnetic toner has a weight-average particle diameter of from 3 &mgr;m to 10 &mgr;m, a magnetization intensity (saturation magnetization) of from 10 Am2/kg to 50 Am2/kg (emu/g) under application of a magnetic field of 79.6 kA/m (1,000 oersteds), an average circularity of 0.970 or more, a ratio of weight-average particle diameter to number-average particle diameter, of 1.40 or less, iron and an iron compound which stand liberated from the magnetic toner particles at a liberation percentage of from 0.05% to 3.00%, and a resin component having a tetrahydrofuran-insoluble matter in an amount of from 3% by weight to 60% by weight. Also disclosed is an image-forming method making use of the magnetic toner.

Abstract: A toner for developing an electrostatic image excellent in fixing property and particularly in light transmissibility and coloring property and satisfying high image quality and high reliability, and a process for producing the same, as well as a developer for an electrostatic image and a process for forming an image are provided. The toner for developing an electrostatic image contains at least a resin component and colorant particles, and the colorant particles exhibit a dispersion state inside the toner observed by a transmission electron microscope. The dispersion state satisfies two conditions, where (1) the colorant particles have a dispersion average particle diameter of 100 nm or less, and (2) the colorant particles have a content of coarse particles of a diameter of 400 nm or more 5% by number or less of the total of the colorant particles.

Abstract: A process for producing microspheric toner particles suitable for color toner applications includes forming coarse particles of an amorphous polymer with one or more pigments and optionally a charge control agent followed by reducing the particle size such that it is suitable as toner for high resolution electrostatic imaging. A step of comminuting the particles includes forming a dispersion of the particles in a liquid organic medium and applying shear in the presence of a surfactant. In another embodiment, the invention discloses a process for producing microspheric particles of substantially amorphous resin with an average diameter in the range of from about 2 to about 10 microns. Preferred resins include amorphous polyester resins and ethylene/norbornene copolymers.

Abstract: An image forming method comprises the steps of charging an electrostatic latent image bearing member, imagewise exposing the charged electrostatic latent image bearing member to form an electrostatic latent image thereon, developing the electrostatic latent image with a toner held on a toner holding member to form a toner image and transferring the toner image onto a transfer-receiving medium. The electrostatic latent image is developed by bringing a toner layer formed out of the toner held on the toner holding member into contact with the surface of the electrostatic latent image bearing member. The toner has toner particles containing at least a colorant, a wax and a binder resin. The wax: (a) in a DSC curve measured by a differential scanning calorimeter, shows an endothermic peak in a region from 50° C. to 130° C.