Patent ID: 6875549

Claim:
A toner comprising: toner particles each comprising at least a binder resin and magnetic iron oxide, wherein the toner has a weight-average particle size X (μm) of 4-12 μm; the toner contains particles of at least 3 μm which include: at least 85% by number particles satisfying a circularity Ci of at least 0.900 according to formula (1) below: Ci=L 0 /L (1), wherein in L denotes a peripheral length of a projection image of an individual particle as measured at an image processing resolution of 512×512 pixels (each having a pixel size of 0.3 μm×0.3 μm), and L 0 denotes a peripheral length of a circle giving an identical area as the projection image, and a number-basis percentage Y (%) of particles having a circularity Ci of at least 0.95 0 according to the formula (1) above satisfying a relationship of formula (2) below with respect to the weight-average particle size X (μm) of the toner; Y≧X −0.715 ×exp 5.31 (2); and the toner provides an extract solution showing an absorbance of 1.0-2.5 at a wavelength of 340 nm when the extract solution is obtained by extracting 20 mg of the toner with 5 ml of 3 mol/l-hydrochloric acid for 50 min.