Image forming method

An image forming apparatus comprising:

• a charging means for carrying out charging by applying voltage from the outside to a charging member, which is brought into contact with an electrophotographic photoreceptor;
• an electrostatic latent image-forming means of forming a latent image;
• and
• a toner image-forming means including an image-forming device that visualizes the latent image by using a developer, wherein;
• the charging member uses a charging roll laminated with an ionic conductive elastic material layer and a surface layer, on which an electrocondoctive material is dispersed, on a conductive support;
• and
• the developer that comprises a toner, which satisfies the following requirements:
• (a) the volume average particle size D50v is 3 to 7 μm;
• (b) the volume average particle size distribution index GSDv is 1.25 or less (provided that GSDv=(D84v/D16v)½, where D84v is the value of a particle size at which accumulation from the small size side in the volume distribution of particle sizes is 84%, and D16v is the value of a particle size at which accumulation from the small size side in the volume distribution of particle sizes is 16%;
• (c) the small particle size side-number particle size distribution index GSDp-under is 1.27 or less (provided that GSDp-under=(D50p/D16p), where D50p is the value of a particle size at which accumulation from the small size side in the number distribution of particle sizes is 50% and D16p is particle size value at which accumulation from the small size side in the particle sizes is 16%;
• (d) shape factor SF1=125 to 140 (provided that SF1=(π/4)×(L2/A)×100, where L represents a maximum length and A represents a projected area);
• (e) the ratio of the releasing agent to be exposed from the surface of the toner, whose ratio is measured quantitatively by X-ray photoelectron spectroscopy (XPS), is in a range from 1 to 40%;
• and
• (f) the melting point of the releasing agent, which is measured using a differential scanning calorimeter, is 70 to 130° C. and the content of the releasing agent is 8 to 20% by weight.

A unit for an image forming apparatus comprising, as its constitutional components, an electrophotographic photoreceptor, a charging roll with a laminated an ionic conductive elastic material layer and a surface layer, in which an electroconductive material is dispersed in this order on a conductive support which is brought into contact with the electrophotographic photoreceptor;

• and
• a developer containing a toner which satisfies the following requirements:
• (a) the volume average particle size D50v is 3 to 7 μm;
• (b) the volume average particle size distribution index GSDv is 1.25 or less (provided that GSDv=(D84v/D16v)½, where D84v is the value of a particle size at which accumulation from the small size side in the volume distribution of particle sizes is 84%, and where D16v is the value of a particle size at which accumulation from the small size side in the volume distribution of particle sizes is 16%;
• (c) the small particle size side-number particle size distribution index GSDp-under is 1.27 or less (provided that GSDp-under=(D50p/D16p), where D50p is the value of a particle size at which accumulation from the small size side in the number distribution of particle sizes is 50% and D16p is the value of a particle size at which accumulation from the small size side in the number distribution of particle sizes is 16%;
• (d) shape factor SF1=125 to 140 (provided that SF1=(π/4)×L2/A)×100, where L represents a maximum length and A represents a projected area);
• (e) the ratio of the releasing agent to be exposed from the surface of the toner, whose ratio is measured quantitatively by X-ray photoelectron spectroscopy (XPS), is in a range from 1 to 40%;
• and
• (f) the melting point of the releasing agent, which is measured using a differential scanning calorimeter, is 70 to 130° C. and the content of the releasing agent is 8 to 20% by weight.