A toner comprising a toner particle comprising a resin A, and an external additive A, wherein the resin A is a resin represented by formula (1) below, the resin A is present at the surface of the toner particle, the external additive A is a fine particle containing silicon, the average value of the shape factor SF-1 of the external additive A is from 105 to 120, the average value of the shape factor SF-2 of the external additive A is from 100 to 130.

##STR00001##

The present invention relates to a binder resin composition capable of giving a toner remarkably excellent in fusing property on polypropylene films, and to a toner for developing electrostatic images that contains the binder resin composition. [1] A binder resin composition for toners, containing an amorphous polyester resin which has a polyester resin-derived constituent moiety that is a constituent moiety derived from a polyester resin and a modified polypropylene polymer A-derived constituent moiety that is a constituent moiety derived from a modified polypropylene polymer A having a carboxylic acid group or a carboxylic anhydride group and in which the polyester resin-derived constituent moiety and the modified polypropylene polymer A-derived constituent moiety bond to each other via a covalent bond, wherein the polymer A is a polypropylene polymer terminally-modified with an unsaturated bond-having carboxylic acid compound or an anhydride thereof, and in the polyester resin, the amount of the polymer A-derived constituent unit is 8 parts by mass or more and 30 parts by mass or less relative to 100 parts by mass of the total of the alcohol component and the carboxylic acid component constituting the polyester resin-derived constituent moiety; and [2] a toner for developing electrostatic images, containing the binder resin composition of [1].

A toner comprising a toner particle, wherein the toner particle comprises a binder resin, a resin A, and a resin B, the resin A comprises a substituted or unsubstituted silyl group in a molecule, a substituent of the substituted silyl group is at least one selected from the group consisting of an alkyl group having 1 or more carbon atoms, an alkoxy group having 1 or more carbon atoms, a hydroxy group, a halogen atom, and an aryl group having 6 or more carbon atoms, and the resin B comprises an azo group in a molecule.

An image forming apparatus includes an electrostatic latent image bearer, an electrostatic latent image former, a developing device, a transfer device, and a fixing device. The electrostatic latent image former forms an electrostatic latent image on the electrostatic latent image bearer. The developing device develops the electrostatic latent image with a developer to form a toner image. The transfer device transfers the toner image on a recording medium. The fixing device fixes the toner image on the recording medium. The developer contains an adhesive medium and foamable particles.

The toner for developing electrostatic images, comprising: colored resin particles comprising a binder resin, a colorant and a release agent, and an external additive. The colored resin particles further comprise a styrene-based thermoplastic elastomer. The styrene-based thermoplastic elastomer comprises an isoprene unit. A content of a fatty acid ester compound having a number average molecular weight (Mn) of 500 or more and less than 2,000 as the release agent, is from 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the binder resin.

A toner comprising a toner particle comprising a resin A, and an external additive A, wherein the resin A is a resin represented by formula (1) below, the resin A is present at the surface of the toner particle, the external additive A is a fine particle containing silicon, the average value of the shape factor SF-1 of the external additive A is from 105 to 120, the average value of the shape factor SF-2 of the external additive A is from 100 to 130. ##STR00001##

A toner comprising a resin that contains an amorphous segment and a crystalline segment as a binder resin, wherein a proportion of a tetrahydrofuran-insoluble matter of a resin component is from 40% by mass to 80% by mass; in differential scanning calorimeter measurement of the tetrahydrofuran-insoluble matter, where a temperature of a maximum endothermic peak is denoted by Tm [° C.] and an endothermic quantity is denoted by H(I) [J/g], the following formulas (1) and (2) are satisfied:
55.0≤Tm≤80.0  (1)
10.0≤H(I)≤80.0  (2).

The toner for developing electrostatic images, comprising: colored resin particles comprising a binder resin, a colorant and a release agent, and an external additive. The colored resin particles further comprise a styrene-based thermoplastic elastomer. The styrene-based thermoplastic elastomer comprises an isoprene unit. A content of a fatty acid ester compound having a number average molecular weight (Mn) of 500 or more and less than 2,000 as the release agent, is from 2 parts by mass to 20 parts by mass with respect to 100 parts by mass of the binder resin.

A toner includes polyolefin and has an exothermic peak in a range from 40° C. to 70° C. in a cooling process of the polyolefin by the DSC after a first heating process of the polyolefin by DSC. The polyolefin does not have an exothermic peak in the cooling process of the polyolefin by the DSC after the first heating process of the polyolefin by the DSC, and has an exothermic peak in a range from 0° C. to 30° C. in a second heating process of the polyolefin by the DSC.

An image forming method is provided. The image forming method includes: forming an electrostatic latent image on an electrostatic latent image bearer; developing the electrostatic latent image on the electrostatic latent image bearer with a toner to form a toner image; transferring the toner image from the electrostatic latent image bearer onto a continuous resin film; fixing the toner image on the continuous resin film with a heat roller or a heat belt. The toner contains a maleic-acid-modified polyolefin having a polypropylene block in a main chain.