Kyocera Document Solutions Inc.

Kyocera Mita Corporation

Other

Seiji Kikushima

Takashi Nagai

Toru Takatsuna

Hiroaki Moriyama

Kouzou Teramoto

Hiroko Sugimoto

Hidekazu Tamura

Hiroko Higuchi

Noriya Okamoto

A developing device includes a cylindrical developing roller, a regulation member, a magnetic member, and a synthetic resin member. The regulation member includes a first opposing surface facing an outer circumferential surface of the developing roller. The magnetic member is arranged on a side surface of the regulation member. The synthetic resin member is arranged on a side surface of the magnetic member. The synthetic member includes a second opposing surface facing the outer circumferential surface of the developing roller. The second opposing surface is tilted at 40° or more but 60° or less with respect to the first opposing surface to be increasingly distant from the outer circumferential surface of the developing roller toward an upstream side in a rotating direction of the developing roller. A solubility parameter of a material of the synthetic resin member is 23 (J/cm)or more. Magnetic toner contains toner and resin fine particles.

Developing device

A developing device includes a developing device case, a developer carrier, a regulating blade, a magnet member, and a blade magnet. The regulating blade forms a regulating part. Toner contains toner mother particles containing binder resin and magnetic powder, and silica particles and alumina particles adhered to surfaces of the toner mother particles. The alumina particles has a primary particle size of 150 nm or more and 400 nm or less, and resistivity of 0.1 Ωm or more and 2 Ωm or less. The developing device can execute a developer removal mode in which the developer carrier is rotated in a reverse direction opposite to a forward direction that is a rotation direction at image forming time, in a range of 1/18 or more and ⅕ or less of an outer circumference length of the developer carrier, so as to remove the developer staying at the regulating part.

Developing device and image forming apparatus including same

An electrostatic latent image developing toner includes toner particles containing a binder resin and at least one type of wax. A dispersed-phase diameter distribution of the wax has a peak at a dispersed-phase diameter in a range from 0.04 &#x3bc;m to 0.20 &#x3bc;m and a peak at a dispersed-phase diameter in a range from 1.0 &#x3bc;m to 5.0 &#x3bc;m. The wax includes first wax particles each having a dispersed-phase diameter in the range from 0.04 &#x3bc;m to 0.20 &#x3bc;m and second wax particles each having a dispersed-phase diameter in the range from 1.0 &#x3bc;m to 5.0 &#x3bc;m. A volume ratio of the first wax particles relative to the second wax particles is at least 0.5 and no greater than 1.5.

Electrostatic latent image developing toner

A method for producing a toner includes: dissolving a thermoplastic resin and a thermosetting resin in an organic solvent; mixing the organic solvent containing the thermoplastic resin and the thermosetting resin with an aqueous medium, and micronizing the thermoplastic resin in a mixture obtained; and forming a film of the dissolved thermosetting resin on surfaces of fine particles formed through the micronization.

Method for producing toner

A positively chargeable toner for electrostatic image development according to the present disclosure is formed by aggregating at least binder resin-containing fine particles and colorant-containing fine particles in an aqueous medium in the presence of a dispersing agent and a metal ion to form fine particle aggregates and heating the fine particle aggregates to coalesce components in the fine particle aggregates. The binder resin used is a (meth)acrylic resin or styrene-(meth)acrylic resin having a certain quaternary ammonium group. The hydrophobicity (methanol wettability) is adjusted to a certain range.

Positively chargeable toner for electrostatic image development and developer

A toner for electrostatic-charge image development contains toner particles in which the surfaces of core particles, including a binder resin composed of a polyester resin, are coated with shell layers. The shell layer is formed of a resin composed of a copolymer of monomers including a monomer having a quaternary ammonium group and a (meth)acrylic copolymer. The molar ratio of units derived from a monomer having a quaternary ammonium group is 5 mol % or more and 35 mol % or less.

Toner for electrostatic-charge image development and method for producing toner for electrostatic-charge image development

An electrostatic charge image development toner contains a plurality of toner particles. The plurality of toner particles are each formed to have resin particulates in a surface layer. The resin particulates each include a particulate core and a coating layer covering the particulate core. The particulate core contains a quaternary ammonium salt functional group-containing resin. The coating layer contains one or more resins selected from the group consisting of (meth)acrylic resins and styrene-(meth)acrylic resins.

Electrostatic charge image development toner

The present disclosure aims to provide a toner that is capable of keeping a photoreceptor drum in satisfactory condition for a long period of time and preventing the occurrence of pinholes on the photoreceptor drum, which plays a key role in forming images. The present disclosure provides an electrostatic charge image developing toner in which an external additive is added to toner base particles, wherein the external additive includes inorganic fine particles attached with conductive fine particles, and the conductive fine particles are attached to the inorganic fine particles with certain strength.

Electrostatic charge image developing toner, electrostatic charge image developer, and image forming apparatus

To provide an electrostatic charge developing toner in which resin fine particles and inorganic fine particles are externally added to toner base particles, wherein the toner base particles include at least binder resin and colorant, the resin fine particles are monodispersed and fixed to surfaces of the toner base particles, and following equations are established: a=70 to 160 nm, b/a=0.2 to 0.5, and c/a=0.6 to 0.8, where 'a' represents an average of diameters (nm) of circular surfaces of contact between the fixed resin fine particles and toner base particle surfaces, 'b' represents an average of heights (nm) of the resin fine particles from the contact surfaces, and &#x201c;c&#x201d; represents an average diameter (nm) of the resin fine particle at the height b/2.

Electrostatic charge developing toner, electrostatic charge developing developer, and image forming apparatus

A two-component developer suppresses burying of an external additive into toner particles and a change in charging performance of a toner with time, and secures stable development performance. The two-component developer includes a toner and a carrier and is adjusted so that a rate of change &#x394;A % in BET specific surface area A (m/g) of the toner (=((A&#x2212;A)/A)&#xd7;100) and a rate of change &#x394;C % in charge quantity C (&#x3bc;C/g) of the carrier (=((C&#x2212;C)/C)&#xd7;100) when a mixture of the toner and the carrier is stirred and mixed are both within 10 %. Aand Aindicate BET specific surface areas of the toner when the mixture of the toner and the carrier is stirred and mixed for 1 minute and 120 minutes, and Cand Cindicate charge quantities of the carrier when the mixture is stirred and mixed for 1 minute and 120 minutes.

Two-component developer

A magnetic toner contains, as a magnetic powder, magnetic iron oxide having an octahedral particle shape and an average particle diameter of 0.21 &#x3bc;m or larger and containing 18% or more by weight of FeO. The magnetic toner is so prepared as to have a bulk density A (g/cm) and a magnetic powder content B (% by weight) that fulfill the formulae 0.8&#x2266;A/B&#xd7;100&#x2266;1.6 and 35&#x2266;B&#x2266;50. This alleviates the reddishness of images produced with the magnetic toner, and alleviates the disturbance of a thin toner layer on a developing sleeve and thus the fogging resulting therefrom.

Method for developing an electrostatic latent image

A developing apparatus has a developer supporting member with a surface roughness R in the range from 3.0 to 5.5 &mgr;m and a one-component developer T with a bulk density in the range from 0.35 to 0.55 g/ml, and an image is developed by forming a layer of the developer T on the developer supporting member . This makes it possible to form a thin toner layer stably despite changes in ambient conditions, and to prevent low image density and fogging. The absolute value of the amount of electric charge with which the developer T is charged is preferably in the range from 3.0 to 10.0 &mgr;C/g. The developer supporting member is made preferably of stainless steel.

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Osaka, Japan

Seiji Kikushima