A toner comprising an external additive A, and a toner particle containing a binder resin and a colorant, wherein the external additive A: i) is an external additive that has a charge control agent on the surface thereof; ii) has a wall friction angle calculated from the following formula (1) of not more than 25.0

=/5.0formula (1);

iii) has a number-average particle diameter (D1) of primary particles of at least 70 nm and not more than 500 nm; and iv) has a solidity as given by the following formula (2) of at least 0.40 and not more than 0.90

solidity=area of external additive A/area of region encompassed by envelope for external additive A formula (2).

An electrostatic charge image developing toner includes: toner particles; first silica particles having an average circularity of 0.9 to 1.0, a particle size distribution index of 1.05 to 1.25, and a compression aggregation degree of 60% to 95%; and second silica particles having an average circularity of 0.9 to 1.0, a particle size distribution index of 1.05 to 1.25, and a compression aggregation degree of 60% to 95%, wherein, when an average primary particle diameter of the first silica particles is set as Da (nm) and an average primary particle diameter of the second silica particles is set as Db (nm), relationships of the following Expressions (A1) to (A3) are satisfied: Expression (A1): 80Da120, Expression (A2): 120Db200, and Expression (A3): 10DbDa120.

Provided is a toner including a toner particle containing an amorphous resin, a colorant, a release agent, and a crystalline resin, wherein, when .sub.0.01 represents the extensional viscosity of the toner at a Hencky strain at 90 C. of 0.01 and .sub.0.69 represents the extensional viscosity of the toner at a Hencky strain at 90 C. of 0.69, .sub.0.01 and .sub.0.69 satisfy the relationships of the following formulas (1) and (2):

3.010.sup.4 Pa.sub.0.012.010.sup.5 Paformula (1)

2.0[.sub.0.69/.sub.0.01].formula (2)

An electrostatic charge image developing toner includes kneaded and pulverized toner particles that contain a binder resin and a release agent, the release agent being partially exposed, and an external additive that contains silica particles having a compression aggregation degree of from 60% to 95% and a particle compression ratio of from 0.20 to 0.40.

A method for providing a developer mix having tribocharge uniformity across varying temperature and humidity conditions is provided. Tribocharge uniformity is achieved in the developer mix by performing the step of treating the surface of the polymer coated magnetic carrier particles with hydrophobized titania surface additives before the polymer coated magnetic carrier particles are mixed with the toner particles. The surface treatment with the hydrophobized titania surface additives can be either a spherical, disk, or spindle shaped.

A developer mix used in a dual component development (DCD) system is a mixture of toner particles and magnetic carrier particles, wherein the magnetic carrier particle is surface treated with a hydrophobized titania particle. The surface treatment with a hydrophobized titania particle may be selected from either a spherical, disk, or spindle shaped. Tribocharge of the toner and the toner charge stability across cartridge life or environments may be suitably modified by selecting a preferred size and shape of the hydrophobized titania.

A developer according to an embodiment includes a toner having a color erasable by heating and a carrier. The carrier includes a core portion and a coating portion covering at least 50% of the core portion. The coating portion includes a white-colored additive agent which suppresses an increase in electrification due to friction between the toner and the carrier, a mass of the additive agent being between 20% and 60% of a total mass of the coating portion.

Provided is an apparatus for heat treatment capable of heat-treating toner particles efficiently and uniformly while suppressing increase of coarse particles due to coalescence, to thereby enable stable toner production. The apparatus for heat-treating powder particles each of which contains a binder resin and a colorant includes: a cylindrical treatment chamber in which the powder particles are heat-treated; a columnar member (6) provided so as to protrude from a lower end part of the treatment chamber toward an upper end part thereof; a powder particle supply unit (2) for supplying the powder particles to the treatment chamber; a hot air supply unit (3) for heat-treating the supplied powder particles; and a collection unit (5) for collecting the heat-treated powder particles discharged outside the treatment chamber through a toner discharge port provided on the lower end part side of the treatment chamber. The hot air supply unit is provided so that the hot air is supplied along an inner circumferential surface of the treatment chamber. The powder particle supply unit includes multiple particle supply ports provided on an outer circumferential surface of the columnar member. The toner discharge port is provided in an outer circumferential portion of the treatment chamber so as to keep a rotation direction of the powder particles.

Herein is disclosed an electrostatic ink composition, wherein the composition is formable by combining: chargeable particles comprising a resin, a charge director comprising a sulfosuccinate salt, and a non-polymeric, non-fatty acid having a pK.sub.a, when measured in water at 20 C., of at least 1. Also disclosed herein is a method of forming an electrostatic ink composition, and a method of electrostatic printing.

A toner including a resin; and a colorant wax comprising a plurality of colorant wax particles comprising a colorant core surrounded by a wax shell, wherein the colorant wax particles exhibit a particle size distribution of from about 150 nanometers to less than about 300 nanometers; and wherein the colorant wax is prepared by (a) melting and mixing a dry colorant with at least one wax to form a colorant concentrate, wherein the colorant concentrate contains at least 25 percent by weight of colorant; (b) milling the colorant concentrate of step (a) to form a milled colorant concentrate; (c) combining the milled colorant concentrate of (b) with water and dispersing to form the plurality of colorant wax particles; wherein the melting and mixing of step (a) and the milling of step (b) is done in an immersion media mill; and wherein the combining of step (c) is done using a piston homogenizer.