Patent ID: 7502579
Filing Date: 2009-03-10
Classification: G03G

Abstract:
1. An electrostatic recording device, comprising: a substantially cylindrical recording member, having a rotational axis and arranged to be rotatable about the rotational axis, having a peripheral surface on which an electrostatic latent image is formed and developer is deposited; a charging unit for charging the recording member; an exposing unit for irradiating light onto the charged recording member; a developing device for supplying toner to the recording member to form a toner image thereon; and a transferring unit for transferring the toner image onto a recording medium, wherein the developing device comprises: a developer-accommodating vessel for accommodating developer having a toner and a carrier as primary components; a developer conveying member disposed in the developer accommodating vessel to convey the developer in a direction along the rotational axis; and a developing roller opposing at one side the recording member and at another side the developer conveying member and having an axis, the developing roller comprising a cylindrical part having a peripheral surface and a plurality of magnets of differing polarity, and a sleeve roller disposed on the peripheral surface of the cylindrical part and capable of rotating about the axis for supplying the developer from the developer conveying member to the recording member, wherein the carrier has an average particle size of not greater than 65 μm and a saturation magnetization of not less than 70 emu/g, wherein the surface of the sleeve roller has a roughness of not less than 0.45 times the average particle size of the carrier, wherein one of the magnets is disposed in opposition to the recording member in the cylindrical part, the one of the magnets having a maximum magnetic-flux density of not less than 0.07 T and, wherein a relationship 10*V(cm/s)*L(cm)*M(g/cm