Canon Kabushiki Kaisha

Takuma Ikejiri

Yusuke Hasegawa

Tomohisa Sano

Yoshitaka Suzumura

Satoshi Arimura

Shohei Yamashita

Tetsuya Kinumatsu

Kosuke Fukudome

Kenji Ookubo

A magnetic toner is provided, which has a magnetic toner particle containing a binder resin, a wax, and a magnetic body, wherein, when Dn is a number-average particle diameter of the toner, CVis coefficient of variation of a brightness variance value of the toner in a particle diameter range of Dn &#x2212;0.500 to +0.500, and CVis coefficient of variation of a brightness variance value of the toner in a particle diameter range of Dn &#x2212;1.500 to &#x2212;0.500, a relationship CV/CV&#x2264;1.00 is satisfied; an average brightness of the toner in the range of Dn &#x2212;0.500 to +0.500 is 30.0 to 60.0; and when, in a cross section of the toner observed using a transmission electron microscope, which is divided with a square grid having a side of 0.8 &#x3bc;m, coefficient of variation CVof an occupied area percentage for the magnetic body is 40.0 to 80.0%.

Magnetic toner and image-forming method

Provided is a toner including toner particles, each of which contains a binder resin, a colorant, a releasing agent and a crystalline polyester, wherein in an observation of a cross-section each of the toner particles by transmission electron microscopy, specific toner particles each of which has domains of the crystalline polyester and domains of the releasing agent, are present at a ratio of at least 70% by number of the toner particles in the toner, an arithmetic mean of maximum diameters of the domains of the releasing agent is within prescribed range, and the specific toner particles satisfy prescribed conditions.

Toner

A toner comprising toner particles, each of which contains a binder resin and a colorant, wherein an onset temperature Te (&#xb0; C.) of a storage elastic modulus E' obtained in a powder dynamic viscoelastic measurement on the toner is at least 50&#xb0; C. and not more than 70&#xb0; C., and a value at Te (&#xb0; C.) of a storage elastic modulus G&#x2032; obtained in a pellet dynamic viscoelastic measurement on the toner is at least 4.0&#xd7;10Pa and not more than 1.0&#xd7;10Pa.

A toner comprising a binder resin, a crystalline material, and a colorant, wherein, in a cross section image of the toner, when R (&#x3bc;m) is a long axis of the toner, r (&#x3bc;m) is a long axis of a crystalline material domain, domain A is a domain satisfying formula (ii), and domain B is a domain satisfying formula (iii), the toner in which the domain A and the domain B are both present is at least 50 number %; an number average diameter Rof the long axis of the toner satisfies formula (i); and a number of domain B per toner cross section of one toner is 20 to 300.4 &#x3bc;m&#x2264;&#x2264;12 &#x3bc;m&#x2003;&#x2003;(i)0.125&#x2264;&#x2264;0.375&#x2003;&#x2003;(ii)0.000625&#x2264;&#x2264;0.0625&#x2003;&#x2003;(iii)

A toner comprises toner particles, each of which contains a binder resin, a colorant, a wax and a crystalline polyester. The melting point P(t) of the crystalline polyester is at least 65.0&#xb0; C. and not more than 80.0&#xb0; C., and regarding a storage elastic modulus G' obtained in dynamic viscoelasticity measurement of the toner, where G&#x2032; at 50&#xb0; C. is denoted by G&#x2032;(50), G&#x2032; at 80&#xb0; C. is denoted by G&#x2032;(80), G&#x2032; at 120&#xb0; C. is denoted by G&#x2032;(120), and G&#x2032; at the melting point P(t) of the crystalline polyester is denoted by G&#x2032;(t), the following formulas are satisfied: 4.2&#xd7;10Pa&#x2264;G&#x2032;(50), 3.0&#xd7;10&#x2264;G&#x2032;(50)/G&#x2032;(80), and G&#x2032;(t)/G&#x2032;(120)&#x2264;7.0&#xd7;10.

Provided is a method for producing a toner particle including a step of condensing a raw slurry by using a decanter-type centrifugal separator, in an aqueous medium. The step of condensing the raw slurry is carried out under following conditions: a centrifugal force is at least 500 G and less than 4000 G and a temperature is at least Tg&#x2212;10&#xb0; C. and not more than Tg+10&#xb0; C. And a ratio of a colored particles in condensed slurry is within a prescribed range.

Method for producing toner particle

A method for producing a toner containing a toner particle containing a binder resin, a colorant and a crystalline substance, wherein the method includes the steps of: (I) setting a temperature of a dispersion, in which a coloring particle is dispersed with an aqueous medium, to T(&#xb0; C.), which is higher than the higher of a crystallization temperature Tc(&#xb0; C.) of the crystalline substance and a glass transition temperature Tg(&#xb0; C.) of the coloring particle, the coloring particle containing the binder resin, the colorant and the crystalline substance; (II) cooling the dispersion from the Tto a temperature equal to or lower than the Tg at a cooling rate of at least 5.0&#xb0; C./min after the step (I); and (III) holding the dispersion in a temperature from Tg&#x2212;10 to Tg+10 for at least 30 min after the step (II).

Growing community of inventors

Suntou-gun, Japan

Takuma Ikejiri