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.

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 includes toner base particles and external additives deposited on a surface of the toner base particle. The toner base particle includes an amorphous polyester resin, a crystalline polyester resin, a release agent, and resin particles. An abundance ratio of the crystalline polyester resin in the surface of the toner base particle as observed by TEM is 2.5% or greater but 25% or less. The resin particles are deposited at the surface of the toner base particle as observed by SEM. A ratio of aggregates of the resin particles occupying the surface of the toner base particle is 1% or greater but 70% or less, where R is a major axis of the minimum particle of the resin particles, and the resin particle having a major axis of 3R or greater is determined as the aggregate.

The present disclosure provides processes for producing images with toner particles. In embodiments, toner particles of a certain diameter in size are applied to a substrate as an incomplete monolayer, and then fused to form an image that is a complete monolayer and possesses a thickness less than the diameter of the particles utilized to form the image.

A method of producing resin particles includes a first step of adding a monomer-containing emulsified liquid that contains a polymerizable monomer and an aqueous medium to an aqueous mother medium to polymerize the polymerizable monomer; and a second step of adding an aqueous medium for cooling to the aqueous mother medium after completion of the addition of the monomer-containing emulsified liquid to the aqueous mother medium.

The toner is characterized in that, wherein the binder resin is a resin satisfying at least one of the following specification (A) or (B): (A) the binder resin contains a crystalline resin having a unit (a) represented by the following formula (1) and a resin having a sulfide structure; and (B) the binder resin contains a crystalline resin having the sulfide structure and having the unit (a) represented by the following formula (1):

##STR00001##

wherein the colorant is any colorant selected from the specific group consisting of: carbon black and so on, wherein when the toner is subjected to measurement with a differential scanning calorimeter, a peak temperature of a maximum endothermic peak is present in a range of from 50° C. or more to 70° C. or less, and wherein the maximum endothermic peak has an endothermic quantity of 30 J/g or more and 70 J/g or less.

A toner particle includes a binder resin, a colorant, and a wax. The binder resin includes an amorphous polyester resin and a crystalline polyester resin. The amorphous polyester resin includes, as monomer units, a first monomer having a pendant group, terephthalic acid, and ethylene glycol.

A toner includes toner base particles. Each of the toner base particles includes a binder resin, a colorant, and inorganic filler. An atomic concentration % of Al in the toner base particles as measured by XRF is 0.35 or greater but 0.85 or less. The toner satisfies 0.8<(M1/M2)/(M3/M4)<1.2. M1 is an atomic concentration % of Al in the toner base particles as measured by XPS, M2 is the atomic concentration % of Al in the toner base particles as measured by XRF, and M3 is an atomic concentration % of Al in particles as measured by XPS, and M4 is an atomic concentration % of Al in the particles as measured by XRF. The particles are particles obtained by classifying the toner base particles into 6/5 Dv, and Dv is a volume average particle diameter of the toner base particles.

A toner comprising a toner particle comprising a binder resin, wherein the binder resin comprises a resin A and a resin B, in a differential scanning calorimetric measurement, a peak top temperature of the largest endothermic peak is present within a specific temperature range and an endothermic amount of an endothermic peak derived from the resin A is 30 to 70 J/g per 1 g of the toner, a ratio of content of the resin A in the toner particle is 60.0 to 90.0 mass %, the resin A comprises 40.0 to 70.0 mass % of a monomer unit (a) represented by formula (1) below, and the resin B comprises 5.0 to 30.0 mass % of a monomer unit (b) represented by formula (2) below:

##STR00001## in formulae (1) and (2), R.sup.1 and R.sup.2 denote a hydrogen atom or a methyl group, n and m denote a specific integer.

A toner comprising a toner particle comprising a binder resin, wherein the binder resin has a side-chain crystalline polymer B having a monomer unit A made of at least one polymerizable monomer A selected from the group consisting of (meth)acrylic acid esters having a linear alkyl group having 18 to 36 carbon atoms, and the toner particle comprises boric acid.