Abstract: In an electrophotographic toner, by using as the binder resin a styrene/acrylic resin in which in the gel permeation chromatogram, a high molecular weight peak value appears in a molecular weight region higher than 1.times.10.sup.5, a low molecular weight peak value appears in a molecular weight region of from 2.times.10.sup.4 to 500, a minimum value appears halfways between the two peaks and the ratio (V/P) of the area of the valley to the peak area is lower than 0.3, the internal cohesive force of the binder resin for the toner can be prominently improved while maintaining the low-temperature fixing property and offset resistance at high levels, and pulverization of the toner and formation of the spent toner can be prevented during the developing operation and the durability of the toner can be improved.

Abstract: The present invention provides an electrophotographic developer comprising (i) a toner containing a fixing resin in which the content of an acrylic component is limited to a predetermined range, or a toner of which surface dye density is limited to a predetermined range, and (ii) a carrier coated with a coating resin containing, as an acrylic component, dodecyl methacrylate or 2-hydroxyethyl acrylate.In the electrophotographic developer of the present invention, the electric charging characteristics are always stable.

Abstract: The present invention provides an electrophotographic developer comprising (i) a toner containing, as a fixing resin, a styrene-acrylic copolymer presenting a gel permeation chromatogram showing a molecular-weight distribution in which the detection-starting molecular weight and the detection-ending molecular weight are respectively located in specific ranges, and (ii) a carrier coated with a coating resin which is a styrene-acrylic copolymer containing at least 2-hydroxyethyl acrylate.Even though repeatedly agitated in the developing device, the electrophotographic developer of the present invention is not deteriorated and assures good durability and long life-time.

Abstract: A start developer is described which includes a toner and a carrier, present in a predetermined ratio. The carrier spent amount is adjusted so that it is not less than 0.010% in terms of the amount of carbon, as measured with a carbon analyzer. With this start developer, good quality images may be formed throughout the copying operation, from the initial image forming stage to the repeated image forming stage and through the stabilized image forming stage.

Abstract: A two-component developer for use in dry development of electrostatic charge pattern, comprising a mixture of magnetic carrier particles and electroscopic toner particles, characterized in that said magnetic carrier particles have a relaxation time B (msec) satisfying the equation 0<B<20 when they are situated in a dynamic state and said developer has a relaxation time A (msec) satisfying the equation: 0.35B+11<A<0.35B+14 when it is situated in a dynamic state.

Abstract: Disclosed is a toner for developing a statically charged image, which comprises a fixing resin and, dispersed therein, a colorant and a charge-controlling dye. This toner is characterized in that the tangent (tan .delta.) of the loss angle is in the range of from 0.95 to 1.25 when the storage modulus of elasticity (G') is 10.sup.4 dyne/cm.sup.2. The toner having such rheological characteristics has an excellent fixing property, a high offset resistance, a capacity of forming an image having a high quality and a good durability.

Abstract: Disclosed are a toner for developing a statically charged image and a process for the preparation thereof. If a toner for developing a statically charged image, comprising a binder resin and, dispersed therein, a colorant and a charge-controlling dye, is prepared so that it has a particle size distribution satisfying the requirement represented by the following formula:N<-172.7C+1.45 (1)wherein N represents the number (%) of particles having a particle size larger than 16 .mu.m, as measured by Coulter Counter, and C represents the surface dye concentration (g/g) of toner particles, a copy having a high image density with a drastically reduced visible fogging can be obtained.