A toner comprising: a toner particle comprising a binder resin; and an external additive on a surface of the toner particle, wherein the binder resin comprises a resin having an ester bond, a peak corresponding to boric acid is detected in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal, and when a dispersed solution obtained by dispersing the toner in an aqueous solution containing a surfactant is subjected to a detachment treatment A including shaking for 300 seconds using a shaker, and when an external additive detached from the toner by the detachment treatment A is denoted as external additive A, a charge amount of the external additive A using a standard carrier (F81) is −0.5 μC/g or less.

A toner comprising: a toner particle comprising a binder resin and boric acid; wherein the binder resin comprises an amorphous resin and a crystalline polyester resin, a content of the crystalline polyester resin in the toner is 30.00 to 80.00 mass %, and a content of the boric acid in the toner is 0.10 to 10.00 mass %.

The present invention relates to a binder resin for toners which contains a composite resin that is formed by bonding a styrene-acrylic resin unit and a polyester-based resin unit to each other through a covalent bond, in which an acid value of a styrene-acrylic resin (A) constituting the styrene-acrylic resin unit is not less than 40 mgKOH/g.

A toner includes: toner base particles including a binder resin, a colorant, an inorganic filler, and a release agent; and an external additive. An average circularity of the toner is 0.974 or more but 0.985 or less. A surface roughness parameter Sz of a surface of the toner is 200 nm or more but 500 nm or less, the surface roughness parameter Sz being measured with an atomic force microscope (AFM).

The present invention relates to a process for producing a toner for development of electrostatic images, including step (1): subjecting a polyhydric alcohol component and a polycarboxylic acid component to polycondensation reaction in the presence of a hydroxy group- or carboxy group-containing hydrocarbon wax (W1) to obtain a non-crystalline resin (A) containing a constitutional component derived from the hydrocarbon wax (W1) and also containing a polyester moiety; step (2): dispersing the non-crystalline resin (A) obtained in the step (1) in an aqueous medium to obtain an aqueous dispersion of resin particles (X); step (3): aggregating the resin particles (X) obtained in the step (2) in an aqueous medium in the presence of a crystalline polyester (B) to obtain aggregated particles; and step (4): coalescing the aggregated particles obtained in the step (3).

A toner having a toner particle containing a binder resin, an amorphous polyester, and a colorant, wherein a softening point of the toner is at least 110° C. and not more than 140° C.; an integrated value f1 for stress of the toner is not more than 10 g.Math.m/sec, as measured using a tack tester, with a temperature for a probe end being 150° C. and a press holding time being 0.01 seconds; and an integrated value f2 for stress of the toner is at least 30 g.Math.m/sec, as measured using a tack tester, with a temperature for a probe end being 150° C. and a press holding time being 0.1 seconds.

A method of producing a resin particle dispersion for toner, including, cooling a mixture including a resin particle dispersion containing an amorphous resin and a crystalline resin, and an aqueous medium. Where the cooling includes together fluidizing, continuously mixing, and continuously discharging the mixture of the resin particle dispersion and the aqueous medium.

A lustrous developer according to an embodiment may include: a metallic pigment; and a binder resin. The lustrous developer includes small diameter particles smaller than a volume median diameter of the metallic pigment. A ratio of a volume of particles other than the small diameter particles in the lustrous developer to a volume of the entire lustrous developer is 90.297% or more and 99.314% or less. The volume median diameter of the metallic pigment is 5.91 μm or less.

A toner particle includes a binder resin, a colorant, a releasing agent, and a dispersant. The binder resin includes a non-crystalline polyester resin containing 1 to 15 mol % of a polyfunctional carboxylic acid unit having a pendant group with 3 to 32 carbons and a crystalline polyester resin. An endothermic amount Tg2nd-dH derived from the crystalline polyester resin is 4 to 40 J/g. The releasing agent has a melting point of 60 to 100° C. The dispersant has a melting point of 60 to 100° C. A mass ratio of the dispersant to the releasing agent is 50:50 to 95:5.

A toner has excellent low temperature fixing property, heat resistant preservability, and stable image quality. The toner contains a core including a crystalline polyester, and a shell formed on a surface of the core. An aspect ratio of the crystalline polyester in the toner is within a range from 1 to 3, and an average length of a longitudinal diameter of the crystalline polyester is within a range from 10 nm to 500 nm.