Provided is a toner for development of electrostatic images comprising colored resin particles containing a binder resin, a colorant, a charge control agent, and a release agent, wherein the colored resin particles have a storage modulus G′ (60) at 60° C. of 1.0×10.sup.8 to 5.0×10.sup.8 Pa, a storage modulus G′ (100) at 100° C. of 8.0×10.sup.4 to 2.3×10.sup.5 Pa, and a storage modulus G′ (150) at 150° C. of 1.4×10.sup.4 to 3.0×10.sup.4 Pa, these storage moduli being determined by dynamic viscoelastic analysis.

To provide a charge control agent and a toner having a superior charging characteristic. A charge control agent containing a bis-phthalimide derivative represented by formula. Thus, it is possible to provide a safe, negative chargeability charge control agent with which the rate of rise of the charge can be increased, and which has a high charging amount and poses no problem in terms of waste regulations. Furthermore, it is possible to provide a negatively chargeable toner (and particularly, a negatively chargeable polymerized toner) for electrostatic image development which uses this charging control agent and has a superior charging characteristic.

A toner composition having improved toner usage efficiency, wherein toner particles having an average size range of 1-25 μm may be mixed with an extra particulate additive package including a first small silica surface treated with both a silane and an aminosilane having a primary particle size of about 5 nm-20 nm, a second fumed silica having a primary particle size of 30 nm-60 nm, a third silica having a primary particle size of about 70 nm-120 nm, an electro-conductive titania having a primary particle size of 30 nm-60 nm and an acicular titania having a size of about 1.6 μm to 1.7 μm in length and about 130 nm in diameter. An alternative embodiment of the extra particulate additive package does not include a third silica having a primary particle size of about 70 nm-120 nm.

A toner comprises a toner particle containing an amorphous polyester, wherein the amorphous polyester contains an amorphous polyester 1, the amorphous polyester contains a tin compound and a titanium compound, a Sn/Ti abundance ratio between Sn and Ti in the amorphous polyester according to x-ray fluorescence analysis is 20/80 to 80/20, and a weight-average molecular weight Mw1 of the amorphous polyester 1 according to measurement by gel permeation chromatography (GPC) is Mw1<7,000.

A toner for developing an electrostatic charge image contains toner particles containing at least one binder resin; the Mg element in an amount such that the net intensity of x-ray fluorescence from the Mg element in the toner is 0.10 kcps or more and 1.20 kcps or less; and at least one external additive including particles of a metal salt of a fatty acid.

The present invention is directed to providing a toner having no environmental difference in charging performance, and having high stability of images after output of a large number of copies under environments at high temperature and high humidity in a higher-speed one-component developing system, and a method for producing the toner, and the toner comprises a toner particle including a toner base particle containing a binder resin, a colorant and a releasing agent; and a resin particle adhering to the surface of the toner base particle, wherein the resin particle contains a resin A, and the resin A has an ionic functional group and an acid dissociation constant pKa of 7.0 or more and 9.0 or less, and the resin A has a monovalent group a represented by Formula (1): ##STR00001##

A toner having a toner particle that contains a binder resin, a pigment, a pigment dispersant, and a crystalline polyester, wherein the pigment dispersant has a specific pigment adsorption segment and a polymer moiety and a hydrophobic parameter HP1 for the pigment dispersant and a hydrophobic parameter HP2 for the crystalline polyester satisfy the formula −0.28≦(HP1−HP2)≦0.15.

Disclosed is a toner including toner particles each including a core portion that contains a binder resin, and a surface layer containing an organosilicon polymer, in which each of the toner particles contains a polyvalent metal element having a resistivity of 2.5×10.sup.−8 Ω.Math.m or more and 10.0×10.sup.−8 Ω.Math.m or less at 20° C., and when the toner particles are subjected to X-ray fluorescence analysis, a net intensity originating from the polyvalent metal element is 0.10 kcps or more and 30.00 kcps or less.

An electrostatic charge image developing toner contains toner particles, titanic acid compound particles that are added to an exterior of the toner particles, have a peak existing in a range of 20 nm or more and less than 80 nm in a number-based primary particle size distribution curve, and have an average circularity of 0.88 or more and 0.94 or less, and silica particles that are added to the exterior of the toner particles and have, in a number-based primary particle size distribution curve, a small size-side peak existing in a range of 20 nm or more and less than 80 nm, a large size-side peak existing in a range of 80 nm or more and less than 130 nm, and a valley existing between the small size-side peak and the large size-side peak, in which a difference in a particle size between the peak in the number-based primary particle size distribution curve of the titanic acid compound particles and the small size-side peak in the number-based primary particle size distribution curve of the silica particles is 20 nm or less, and in the number-based primary particle size distribution curve of the silica particles, in a case where the silica particles having a particle size less than the valley are defined as small-sized silica particles, and the silica particles having a particle size equal to or larger than the valley are defined as large-sized silica particles, an average circularity of the small-sized silica particles is 0.88 or more and 0.94 or less.

Provided is a positive-charging toner having a toner particle that contains a binder resin, the binder resin contains a polymer A having a first monomer unit derived from a first polymerizable monomer, and a second monomer unit derived from a second polymerizable monomer, the first polymerizable monomer is at least one selected from the group consisting of (meth)acrylic acid esters having a C18 to C36 alkyl group, the content of the first monomer unit in the polymer A is 5.0 to 60.0 mol % and the content of the second monomer unit is 20.0 to 95.0 mol %, SP.sub.11 of the first monomer unit and SP.sub.21 of the second monomer unit satisfy 3.00≤(SP.sub.21−SP.sub.11)≤25.00, and the work function of the toner is 5.0 to 5.4 V.