Developing apparatus, developing method, image forming apparatus and image forming method

摘要

The present invention provides a developing apparatus including a toner, a toner carrying member and a regulating member, wherein the toner is a magnetic toner including a toner particle, a first fine silica particle having a number average primary particle diameter of 5 to 20 nm and a second fine silica particle having a number average primary particle diameter of 40 to 200 nm, the second fine silica particle is a fine silica particle produced by a sol-gel method, the toner has a total energy of 270 to 355 mJ/(g/ml), the toner carrying member has a substrate, an elastic layer and a surface layer including a urethane resin, and the urethane resin has a partial structure derived from a reaction of a particular amine type compound with a polyisocyanate.

主权项

1. A developing apparatus for developing an electrostatic latent image formed on a surface of an electrostatic latent image bearing member to form a toner image on the surface of the electrostatic latent image bearing member, wherein
the developing apparatus comprises a toner for developing the electrostatic latent image, a toner carrying member for carrying the toner, and a regulating member for regulating a layer thickness of the toner carried by the toner carrying member, the toner is a magnetic toner comprising a toner particle containing a binder resin and a magnetic member, a first fine silica particle having a number average primary particle diameter (D1) of 5 nm or more and 20 nm or less, and a second fine silica particle having a number average primary particle diameter (D1) of 40 nm or more and 200 nm or less, the second fine silica particle is a fine silica particle produced by a sol-gel method, the toner has a total energy of 270 mJ/(g/ml) or more and 355 mJ/(g/ml) or less, the toner carrying member has a substrate, an elastic layer and a surface layer comprising a urethane resin, and the urethane resin has a partial structure derived from a reaction of a compound represented by the following structural formula (1) with a polyisocyanate: wherein n denotes an integer of 1 or more and 4 or less, each R3 independently represents any selected from the group consisting of the following (a) to (c): (a) a hydroxyalkyl group having 2 or more and 8 or less carbon atoms; (b) an aminoalkyl group having 2 or more and 8 or less carbon atoms; and (c) a group represented by the following structural formula (2), and R4 represents an alkylene group having 2 or more and 4 or less carbon atoms: wherein m denotes an integer of 2 or more and 3 or less, and R5 represents an alkylene group having 2 or more and 5 or less carbon atoms.