Abstract: A developer for developing electrostatic latent images is constituted by a toner, and negatively chargeable spherical resin particles having an average particle size of 0.03-1.0 micron and a volume resistivity of 10.sup.6 -10.sup.12 ohm.cm. The toner may comprise toner particles and hydrophobic inorganic fine powder, which is generally used in a larger amount than the negatively chargeable spherical resin particles. The negatively chargeable spherical resin particles function to provide a toner image which is faithful to an electrostatic latent image formed on a photosensitive member while preventing toner-sticking onto the photosensitive member preferably in combination with a contact-charging means for charging the photosensitive member.

Abstract: A toner for developing electrostatic images is constituted from a binder resin, and a metal salt or a metal complex. Through the various interaction between the components, the toner is provided with unique viscoelastic properties including: a dynamic modulus G'.sub.120-200 at 120.degree.-200.degree. C. of 2.times.10.sup.3 or higher to below 5.times.10.sup.5 [dyne/cm.sup.2 ] as measured in the frequency range of 1.times.10.sup.-2 -1 (Hz); a loss modulus G".sub.120-200 at 120.degree.-200.degree. C. of 2.times.10.sup.3 or higher to below 5.times.10.sup.5 [dyne/cm.sup.2 ] as measured in the frequency range of 1.times.10.sup.-2 -1 (Hz); a dynamic modulus G'.sub.200 at 200.degree. C. and a frequency f satisfying an approximated linear relationship according to the least squares method of: logG'.sub.200 =a.multidot.log.multidot.f+log b, wherein a denotes a positive number of 0.25 or smaller and b denotes a constant; and a ratio (G'.sub.200)/(G'.sub.120) of below 0.25 wherein (G'.sub.

Abstract: A developer for developing electrostatic latent images is constituted by a toner, and negatively chargeable spherical resin particles having an average particle size of 0.03-1.0 micron and a volume resistivity of 10.sup.6 -10.sup.12 ohm.cm. The toner may comprise toner particles and hydrophobic inorganic fine powder, which is generally used in a larger amount than the negatively charageable spherical resin particles. The negatively chargeable spherical resin particles function to provide a toner image which is faithful to an electrostatic latent image formed on a photosensitive member while preventing toner-sticking onto the photosensitive member preferably in combination with a contact-charging means for charging the photosensitive member.

Abstract: A magnetic developer for developing an electrostatic latent image, including hydrophobic silica fine powder and an insulating magnetic toner comprising at least a binder resin and a magnetic material comprising spherical magnetic particles; wherein 0.16 to 1.6 wt. parts of the hydrophobic silica fine powder is mixed with 100 wt. parts of the insulating magnetic toner; the developer contains 17-60% by number of magnetic toner particles having a particles size of 5 microns of smaller, 5-50% by number of magnetic toner particles having a particle size of 6.35-10.08 microns, and 2.0% by volume or less of magnetic toner particles having a particle size of 12.7 microns or larger.

Abstract: An encapsulated toner for electrophotography is produced through a process, comprising: preparing a solution of a shell material resin set to an acidic (or basic) pH region; dispersing solid core particles in the solution to form a dispersion; changing the pH of the dispersion to a pH region, which is preferably a basic (or acidic) pH region, where the shell material resin is precipitated from the dispersion; and coating the solid core particles with the precipitated shell material resin. The shell material is preferably a proton-attracting basic (or dissociative acidic) vinyl-type copolymer and is dissolved in a pH-adjusted aqueous medium comprising water and a polar solvent, such as a lower alcohol. Thus, an encapsulated toner with excellent triboelectric chargeability and environmental characteristic is prepared without coalescence of capsules or formation of free shells.