Developing assembly, process cartridge and image-forming method

A process cartridge comprising a latent-image-bearing member for holding thereon an electrostatic latent image;

• a charging means for charging the latent-image-bearing member electrostatically;
• and
• a developing assembly for developing the electrostatic latent image formed on the latent-image-bearing member, by the use of a developer to form a developer image;
• said developing assembly and said latent-image-bearing member being set integral as one unit and being so constructed as to be detachably mountable to the main body of an image-forming apparatus;
• said developer comprising toner particles containing at least a binder resin and a colorant, and conductive fine particles;
• said toner particles having a Circularity a of less than 0.970 as found from the following expression:
• Circularity a=L0/L
• where L0 represents the circumferential length of a circle having the same projected area as a particle image, and L represents the circumferential length of a projected image of a particle;
• and
• said developing assembly having at least a developing container for holding therein the developer, a developer-carrying member for holding thereon the developer held in the developing container and transporting the developer to a developing zone, and a developer layer thickness regulation member for regulating the layer thickness of the developer to be held on the developer-carrying member;
• said developer-carrying member having at least a substrate and a resin coat layer formed on the substrate;
• said resin coat layer containing at least a coat layer binder resin and a positively chargeable material.

An image-forming method comprising:

• a charging step of charging a latent-image-bearing member electrostatically;
• a latent-image-forming step of writing image information as an electrostatic latent image on the charged surface of the latent-image-bearing member having been charged in the charging step;
• a developing step of developing the electrostatic latent image to render it visible as a developer image by means of a developing assembly having a developer-carrying member which, holding thereon a developer, transports the developer to a developing zone facing the latent-image-bearing member;
• a transfer step of transferring the developer image to a transfer sheet;
• and
• a fixing step of fixing by a fixing means the developer image having been transferred to the transfer sheet;
• these steps being repeated to form images;
• said developer comprising toner particles containing at least a binder resin and a colorant, and conductive fine particles;
• said toner particles having a Circularity a of less than 0.970 as found from the following expression:
• Circularity a=L0/L
• where L0 represents the circumferential length of a circle having the same projected area as a particle image, and L represents the circumferential length of a projected image of a particle;
• and
• said developing assembly having at least a developing container for holding therein the developer, a developer-carrying member for holding thereon the developer held in the developing container and transporting the developer to a developing zone, and a developer layer thickness regulation member for regulating the layer thickness of the developer to be held on the developer-carrying member;
• said developer-carrying member having at least a substrate and a resin coat layer formed on the substrate;
• said resin coat layer containing at least a coat layer binder resin and a positively chargeable material.