Abstract: A developing device includes a toner supplying roller, a developing roller for transferring the one-component toner to a developing position by performing a developing rotation in an image forming operation and moving away from the developing position, a sealing member arranged in a vicinity of the developing roller, and a toner layer regulating roller arranged in contact with the developing roller for locking a rotating operation in the image forming operation, for regulating the one-component toner which adheres on a surface of the developing roller into a thin layer and for freely following the developing roller in a non-image forming operation. A compulsory toner consumption operation is performed to supply toner onto the image bearing member after termination of the non-image forming operation.

Abstract: A protecting layer is formed on a surface of an image carrier with a protecting agent that contains at least an organic compound having melting property of which penetration at 25° C. ranges from 3 millimeters to 30 millimeters, and organic compound particles having thermal decomposition property of which a weight average particle size ranges from 2 micrometers to 20 micrometers. A melting temperature of the organic compound is lower than a decomposition temperature of the organic compound particles, and a volume ratio of the organic compound to the organic compound particles ranges from 99/1 to 50/50.

Abstract: A protective agent for forming a protective layer on the surface of an image carrier includes at least a hydrophilic organic compound and an amphiphilic organic compound at a ratio of 1/99 to 20/80. Preferably, the hydrophilic organic compound contains at least one selected from a polysaccharide and a polyether compound, or the amphiphilic organic compound contains a nonionic surfactant.

Abstract: To provide an image bearing member protecting agent that includes at least a hydrophobic organic compound and an amphiphile organic compound. Preferred embodiments are that the hydrophobic organic compound is a hydrocarbon wax, and the hydrocarbon wax is at least a wax selected from normal paraffins, isoparaffins, and cycloparaffins; and that the amphiphile organic compound is an polyalcohol esterified compound including a nonionic surface active surfactant, and the nonionic surface active surfactant is an alkyl carboxylic acid represented by a structural formula, CnH2n+1COOH.

Abstract: A developing device includes a toner supplying roller, a developing roller for transferring the one-component toner to a developing position by performing a developing rotation in an image forming operation and moving away from the developing position, a sealing member arranged in a vicinity of the developing roller, and a toner layer regulating roller arranged in contact with the developing roller for locking a rotating operation in the image forming operation, for regulating the one-component toner which adheres on a surface of the developing roller into a thin layer and for freely following the developing roller in a non-image forming operation.

Abstract: An image forming apparatus including an image bearing member and a developing device configured to develop an electrostatic image on the image bearing member with a toner to form a toner image thereon and including a developing unit configured to develop the electrostatic image, and a toner cartridge configured to supply the toner to the developing unit through at least one opening, wherein the developing device circulates the toner between the toner cartridge and the developing unit through the at least one opening, and wherein the internal temperature of the hopper is higher than that of the cartridge and the ratio of a charge quantity distribution parameter of the toner under a condition of 45° C. and 54% RH to that under a condition of 25° C. and 54% RH is greater than 0.9 and less than 1.5.

Abstract: A developing device including a developing unit configured to develop an electrostatic latent image with a toner; a toner cartridge configured to contain the toner and supply the toner to the developing unit, and including an agitator configured to agitate the toner, wherein the toner cartridge is detachably attached to the developing unit; at least one opening configured to pass the toner between the developing unit and the toner cartridge; and at least one control valve configured to open and shut the opening, wherein a toner replacement ratio (b/a) of the developing device satisfies relationship 0.05?b/a?2.0, wherein a represents an amount of the toner supplied to the developing unit from the toner cartridge per a unit time and b represents an amount of the toner discharged to the toner cartridge from the developing unit per the unit time.