Image forming method and toner set for developing electrostatic latent image

In an image forming method using a black toner and a color toner other than the black toner, comprising:

• developing an electrostatic latent image with a black toner and a color toner other than the black toner;
• transferring a developed image of the black toner and the color toner onto an image support;
• and fixing a transferred image of the black toner and the color toner on the image support to provide a visible image,
• wherein the improvement comprises the black toner and the color toner each comprise a binder resin including a polyester resin being a combination of an amorphous polyester resin and a crystalline polyester resin as a main component and a vinyl resin, a releasing agent, and an external additive, and
• the following formula (1) and formula (2) are satisfied wherein Vk % by mass is a content of the vinyl resin relative to total mass of the binder resin included in the black toner, Vc % by mass is a content of the vinyl resin relative to total mass of the binder resin included in the color toner, Wk % by mass is a content of the releasing agent relative to the total mass of the binder resin included in the black toner, and Wc % by mass is a content of the releasing agent relative to the total mass of the binder resin included in the color toner:
• 2<Vk−Vc<50 (1)
• 2<Wc−Wk<10 (2),
• the Vk is 20 to 50% by mass, and the Vc is from 10 to 30% by mass, and
• the Wk is 3 to 20% by mass, and the Wc is more than 5% by mass and less than 30% by mass,
• wherein a mass ratio of the amorphous polyester resin to the crystalline polyester resin is 60/40 to 90/10, and
• wherein the black toner and the color toner each exhibit a difference in charge reduction relative to each other of 9 μC/g or less, the charge reduction being the difference in charge amount for each toner measured at initial printing and measured after printing 10,000 sheets.