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 developing device includes a frame, a cylindrical developer carrying member rotatably supported by the frame and configured to carry a developer containing toner particles, and a regulating member fixed to the frame at one end thereof and including a contact portion which contacts the developer carrying member at the other end of the regulating member and which forms a contact nip between the regulating member and the developer carrying member. When a position of the contact portion where a maximum of a pressure distribution of the contact portion to the developer carrying member with respect to a rotational direction of the developer carrying member is indicated is a reference position, the contact portion includes a first surface portion positioned upstream of the reference position and a second surface portion positioned downstream of the reference position with respect to the rotational direction.

Toners are provided which may comprise toner particles, a colorant, and optionally, a wax, wherein the toner particles comprise a resin comprising a polymerization product of reactants comprising a dioxane/dioxolane monomer and a vinyl co-monomer, wherein the dioxane/dioxolane monomer is an ester of (meth)acrylic acid with an alcohol comprising a dioxane moiety, an ester of (meth)acrylic acid with an alcohol comprising a dioxolane moiety, or both.

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 %.

A toner comprising: a toner particle comprising a binder resin and boric acid; and an external additive A having a primary particle major diameter of 80 to 200 nm, wherein in ATR-IR analysis of the toner particle in an ATR method using germanium as an ATR crystal, a peak corresponding to boric acid is detected, the average value of a shape factor SF-1 of the external additive A is 105 to 250, and the average value of a shape factor SF-2 of the external additive A is 102 to 250.

A method of manufacturing toner particles, including a step of drying wet toner particles with a drying unit, the wet toner particles being obtained from an aqueous dispersion medium, wherein the drying unit includes a loop-type flash dryer in which the wet toner particles to be dried are supplied to a gas stream circulating in a loop-type drying pipe, the loop-type flash dryer includes: (i) a loop-type drying pipe; (ii) an inlet port for supplying wet toner particles to the loop-type drying pipe; (iii) an outlet port for discharging dried toner particles from the loop-type drying pipe; (iv) a first blowing port for blowing gas into the loop-type drying pipe; and (v) second blowing ports for blowing gas into the loop-type drying pipe.

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 comprising a toner particle, and an external additive on a surface of the toner particle, wherein the external additive comprises an agglomerate of fine silica particles surface-treated with silicone oil; when a number-average particle diameter of the agglomerate of the fine silica particles is defined as Rb, the Rb is 12 to 80 nm; when an integrated value of a D unit is defined as A, which obtained when an integrated value of a Q unit is set to 100 in a CP/MAS measurement in a .sup.29Si-solid-state NMR of the fine silica particles, the A is 120 to 300, and the agglomerate of the fine silica particles has a coefficient of variation of particle diameters of 1.00 to 3.00, based on a number of the agglomerate of the fine silica particles.

A toner comprising a toner particle comprising a binder resin and boric acid, wherein the toner has an average circularity of 0.95 or more, and the toner has a shape factor SF1 of 105 to 125, and a method for producing to provide a toner with excellent durability for which the improvement of transfer rate with the above physical characteristics.

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).