Magenta toner for electrophotography and full color image formation method

A developer comprising a magenta toner for electrophotography and a carrier, the magenta toner including at least a naphthol pigment having a structure represented by the following general formula (1) as a colorant and a binder resin, and having a shape factor SF1 of 110 to 140 obtained by the equation below and a volume average particle size of 2 to 9 μm:

• 18
• wherein R represents the following group,
• 19
• and R′ represents a hydrogen atom, an alkyl group or a methoxy group;
• SF1=R2/A×π/4×100
• wherein R represents the maximum length of the toner and A represents the projected area of the toner.

A method of producing a magenta toner for electrophotography comprising the steps of:

• forming aggregated particles containing binder resin particles in a dispersion containing the binder resin particles to prepare an aggregated particle dispersion;
• and
• coalescing the aggregated particles,
• wherein the produced toner contains a binder resin and, as a colorant, at least a naphthol pigment having a structure represented by the general formula (1), and has a shape factor SF1 of 110 to 140 obtained by the equation below and a volume average particle size of 2 to 9 μm.
• 20
• wherein R represents the following group,
• 21
• and R′ represents a hydrogen atom, an alkyl group or a methoxy group;
• SF1=R2/A×π/4×100
• wherein R represents the maximum length of the toner and A represents the projected area of the toner.

A method of forming a full color image comprising the steps of:

• forming an electrostatic latent image on a photoreceptor;
• developing the electrostatic latent image using a developer containing a toner, to form a toner image;
• transferring the toner image onto a recording medium;
• and
• thermally fixing the toner image on the recording medium,
• wherein the toner is a magenta toner for electrophotography including at least a naphthol pigment having a structure represented by the following general formula (1) as the colorant and a binder resin, and having a shape factor SF1 of 110 to 140 obtained by the equation below and a volume average particle size of 2 to 9 μm.
• 22
• wherein R represents the following group,
• 23
• and R′ represents a hydrogen atom, an alkyl group or a methoxy group;
• SF1=R2/A×π/4×100
• wherein R represents the maximum length of the toner and A represents the projected area of the toner.