Polyester resin for toner, toner, developer, and image formation device

摘要

Provided is a toner-use polyester resin that comprises a framework derived from an alcohol component and a framework derived from a carboxylic acid component, the alcohol component containing an aliphatic alcohol which is at least trivalent, and the toner-use polyester resin fulfills the following expressions (1)-(3). 4,000 ≤ weight-average molecular weight (Mw) ≤ 25,000 ... Expression (2) 0.5 ≤ (quantity of aliphatic alcohol which is at least trivalent) ≤ 6.5 ... Expression (3) The quantity of aliphatic alcohol which is at least trivalent in expression (1) and expression (3) is the mol% of the aliphatic alcohol that is at least trivalent with respect to the total amount of the alcohol component.