Abstract: A resin-coated carrier for two component type developers, with carrier particles having a carrier core material and a coat layer which covers the surface of the carrier core material. The resin-coated carrier has a 50% particle diameter C (D.sub.50) from 25 .mu.m to 70 .mu.m, contains carrier particles smaller than 22 .mu.m in particle diameter in an amount from 0.1% by number to 20% by number and contains carrier particles of 62 .mu.m or larger in particle diameter in an amount from 2% by number to 35% by number. The carrier core material has a BET specific surface area SW1 where the coat layer has been removed and the resin-coated carrier has a BET specific surface area SW2. The SW1 and SW2 satisfy the following expression (I), and the resin-coated carrier satisfies a shape factor SF-1 of the following expression (II) and a shape factor SF-2 of the following expression (III):80.ltoreq.SW1-SW2.ltoreq.650(cm.sup.2 /g) (I)110.ltoreq.SF-1.ltoreq.160 (II)105.ltoreq.SF-2.ltoreq.

Abstract: A yellow toner for developing electrostatic images is formed of yellow toner particles containing a binder resin and a yellow colorant. The yellow toner has a storage modulus G'.sub.180 at 180.degree. C. and a minimum storage modulus G'.sub.min(120-170) in a temperature range of 120-170.degree. C. giving a ratio [G'.sub.180 /G'.sub.min(120-170) ] of 2.0-8.0. The binder resin comprises a polyester resin having a glass transition temperature of 50-65.degree. C. and an acid value of 2.0-25.0 mgKOH/g. The yellow toner is a compound represented by Formula (1) below:Formula (1): ##STR1## The primary particles of the yellow colorant exhibit a length/breadth ratio of at most 1.5. The yellow colorant is dispersed in the toner particles as independent particles (including primary particles and secondary particles) providing a number-average particle size of 0.1-0.7 .mu.m. The yellow toner is provided with improved fixability and anti-offset property as well as good color toner performances.

Abstract: A color toner has (i) color toner particles containing at least a binder resin and a colorant and (ii) an external additive. The color toner has a weight-average particle diameter of 5 to 8 .mu.m and a number-average particle diameter of 4.5 to 7.5 .mu.m, and contains 5 to 40% by number of particles having a particle diameter of 4 .mu.m or less in the number distribution of the color toner and 7% by volume or less of particles having a particle diameter of 10.08 .mu.m or more in the volume distribution of the color toner. The inorganic powder selected from the group consisting of a strontium titanate powder, a cerium oxide powder and a calcium titanate powder, and a hydrophobic fine alumina powder are externally added to the color toner particles as the external additives, the inorganic powder has a longitudinal average particle diameter of 0.2 to 2 .mu.m, and the hydrophobic fine alumina powder has a longitudinal average particle diameter of 0.005 to 0.1 .mu.m.

Abstract: An electrophotographic two-component type developer includes a toner and a magnetic carrier showing stable charge-imparting performances for a long period of continuous image formation and wherein various environmental conditions. The magnetic carrier comprises: magnetic carrier core particles and a silicone resin coating the magnetic carrier core particles; wherein the silicone resin is characterized by having (i) both (a) a --COO-- group and (b) a phenyl group or nitrogen-containing group, (ii) a carbon content attributable to the --COO-- group of 10-70 atomic % of silicon constituting the silicone resin, based on ESCA, and (iii) a carbon content attributable to the phenyl group of 0.1-300 atomic % or a nitrogen content attributable to the nitrogen-containing group of 0.01-10 atomic %, respectively, of the carbon content attributable to the --COO-- group, based on ESCA.

Abstract: A toner contains toner particles and fine alumina particles. The toner particles include a binding resin and a colorant. The fine alumina particles contain 200 to 700 .mu.g of zirconium compound per gram of alumina. The toner may be used as a one-component developer or as a two-component developer with a carrier.

Abstract: A magenta toner for developing electrostatic images is formed of a binder resin, and a quinacridone pigment providing an X-ray diffraction spectrum showing two peaks in a Bragg angle (2.theta.) region of 5-10 deg. The magenta toner has an improved light fastness, may have a desired hue comparable to a printing process ink and is suitably used for electrophotographic full-color image formation. The magenta toner may preferably be formed through a process including a first kneading step starting from wet blending of a binder resin and two paste pigments including quinacridone and 2,9-dimethylquinacridone, respectively, under mild conditions not causing crystal transformation to form a master batch and a second kneading step of diluting the master batch together with other additive.

Abstract: A toner for developing an electrostatic image is formed from toner particles containing at least a binder resin, a colorant and an organometallic compound. The binder resin in the toner particles has a tetrahydrofuran-insoluble (THF-insoluble) content of at most 5.0 wt.% based on the binder resin. The toner has a glass transition temperature of 50.degree.-80.degree. C. The toner further has storage modulus characteristics including a storage modulus at 80.degree. C. (G'.sub.80) of 1.times.10.sup.4 -5.times.10.sup.6 ?dyn/cm.sup.2 !, a storage modulus at 130.degree. C. (G'.sub.130) providing a ratio G'.sub.80 /G'.sub.130 of 10-5.times.10.sup.3, and a storage modulus curve showing a minimum (G'min) in a temperature region of 110.degree.-190.degree. C. The toner especially exhibits excellent low-temperature fixability, anti-high temperature offset characteristic, storage stability and color-miscibility.

Abstract: A carrier for electrophotography is constituted by magnetic carrier core particles and a resin coating layer coating the magnetic carrier core particles. The carrier core particles contain a magnetic ferrite component represented by the following formula (I):(Fe.sub.2 O.sub.3).sub.x (A).sub.y (B).sub.z (I),wherein A denotes a member selected from the group consisting of MgO, AgO and mixtures thereof; B denotes a member selected from the group consisting of Li.sub.2 O, MnO, CaO, SrO, Al.sub.2 O.sub.3, SiO.sub.2 and mixtures thereof; and x, y and z are numbers representing weight ratios and satisfying the relation of: 0.2.ltoreq.x.ltoreq.0.95, 0.005.ltoreq.y.ltoreq.0.3, 0<z.ltoreq.0.795, and x+y+z.ltoreq.1. The coated carrier particles thus formed exhibit excellent performances in continuous image formation.

Abstract: A toner for developing electrostatic images is formed of toner particles comprising (a) a binder resin, (b) a colorant or magnetic material, (c) an aromatic hydroxycarboxylic acid (A), and (d) a metal compound of the aromatic hydroxycarboxylic acid (A). The aromatic hydroxycarboxylic acid (A) and the metal compound of the aromatic hydroxycarboxylic acid (A) are contained in a weight ratio of 1:99 to 10:90. As a result of co-inclusion of a small amount of the aromatic hydroxycarboxylic acid (A) in addition to the metal compound thereof, the resultant toner is provided with a quick chargeability in a low humidity environment and an improved level of triboelectric charge in a high humidity environment, presumably because of the stabilization effect of the small amount of the aromatic hydroxycarboxylic acid (A) on the metal compound thereof.

Abstract: A toner for developing an electrostatic image is formed from toner particles containing a binder resin, a colorant, and a charge-controlling agent. The charge-controlling agent comprises an aromatic oxycarboxylic acid, a metal compound of the aromatic oxycarboxylic acid, and an inorganic compound formed from an inorganic anion and an inorganic cation. The aromatic oxycarboxylic acid, the metal compound of the aromatic carboxylic acid and the inorganic anion are contained in proportions of A (wt. %), B (wt. %) and C (ppm), respectively, satisfying the following conditions: 1/99.ltoreq.A/B.ltoreq.20/80, and 10.sup.2 .ltoreq.C. Because of the inclusion of an inorganic compound providing a sufficient amount of inorganic anion, the charge-controlling agent shows a stable charge-controlling characteristic, and the resultant toner exhibits a stable developing performance and transferability in continuous image formation in various environmental conditions.

Abstract: The present invention provides a toner, particularly color toner, for developing an electrostatic image, which comprises toner particles containing a mixture of a binder resin, a coloring agend and compounds (I) and (II).