US 6,150,062 A · Toners for developing electrostatic latent images, developers for electrostatic latent images and methods for forming images

Abstract

A toner for developing an electrostatic latent image includes at least coloring particles containing a colorant and a binder resin. The volume average particle size of the coloring particle is 1.0 to 5.0 .mu.m. The toner is further characterized in that (1) the relationship between the quantity of the electric charge and the particle size is adjusted appropriately, (2) the particle size distribution is adjusted appropriately and/or (3) an external additive comprising at least an ultra microparticle and a super-ultra microparticle may be added, the rate of coating on the coloring particle being adjusted appropriately. A method for forming an image includes (1) a developing step in which a toner layer is formed on the surface of a developer support arranged opposed to a latent image support and an electrostatic latent image on the latent image support is developed with the toner layer to obtain a toner image and (2) a transfer step in which the toner image formed is transferred to a transfer material. The Rz of at least an image receiving region of the transfer material provided for the transfer step is preferably 10 .mu.m or less.

Claims37

Dependent claims

A toner for developing an electrostatic latent image comprising coloring particles containing a colorant and a binder resin, wherein a volume average particle size of the coloring particles is 1.0 to 5.0 .mu.m, wherein coloring particles having a particle size of 1.0 .mu.m or less are present in an amount of 20% by number or less of a total number of coloring particles and coloring particles having a particle size exceeding 5.0 .mu.m are present in an amount of 10% by number or less of the total number of coloring particles, and wherein the colorant is a pigment.

A toner for developing an electrostatic latent image comprising coloring particles containing a colorant and binder resin, and an external additive, wherein

(a) a volume average particle size of the coloring particles is 1.0 to 5.0 .mu.m, and wherein coloring particles having a particle size of 1.0 .mu.m or less are present in an amount of 20% by number or less of a total number of coloring particles, and coloring particles having a particle size exceeding 5.0 .mu.m are present in an amount of 10% by number or less of the total number of coloring particles,
(b) the external additive comprises at least one type of ultra microparticles having an average primary particle size of 30 nm to 200 nm and at least one type of super-ultra microparticles having an average primary particle size of 5 nm or more and less than 30 nm, and
(c) coating rates, Fa and Fb, of the external additive based on a surface of the coloring particles obtained according to Formula (1)
F=.sqroot.3.multidot.D.multidot..rho..sub..tau. .multidot.(2.pi..multidot.z.multidot..rho..sub..sigma.).sup.-1 .multidot.C.times.100 (1)
wherein F denotes a coating rate (%), D denotes the volume average particle size of the coloring particles (.mu.m), .rho..sub..tau. denotes a true specific gravity of the coloring particles, z denotes an average primary particle size of the additive, .rho..sub..sigma. denotes the true specific gravity of an additive, and C denotes the ratio (x/y) of the weight of the additive, x (g), to the weight of the coloring particles, y (g),
for the ultra microparticles and the super-ultra microparticles, respectively, are both 20% or more, and the total of the coating rate of the entire additive is 100% or less.

3 more elements

Dependencies are inferred from the claim text.

Toners for developing electrostatic latent images, developers for electrostatic latent images and methods for forming images

Life of this patent

Toners for developing electrostatic latent images, developers for electrostatic latent images and methods for forming images

Life of this patent

Abstract

Claims37