Developing device


PURPOSE:To stir dispersively the 2nd developer carried along the outer circumferential surface of a rotating sleeve and to allow electrostatic attracting force to exert on the 1st mixed toner effectively, and to improve the efficiency of the removal of the mixed toner, by providing magnets in the rotating sleeve and forming plural adjacent magnetic poles with the same polarity. CONSTITUTION:The 2nd developer 8 attracted to the outer circumferential surface of the nonmagnetic rotating sleeve 7b by the magnetic force of a fixed magnetic toll 7a is carried circumferentially. A toner 8a is electrified by friction to the positive polarity, and plural magnetic poles 12a having the same polarity are formed closely to the outer circumferential surface of the roll 7a; an electrostatic attracting roll 12b is provided at a place opposite to the magnetic poles 12a so that an electrostatic attracting magnetic field exerts on the developer 8 while isolating from the outer circumferential surface of the roll 7a and scattering dispersively by conveyance force and the repulsive force of the magnetic poles 12a after conveyed by the roll 7b to the positions of the poles 12a, and a power source 12c is connected to the roll 7b and magnetic poles 12b to generate a potential having the same polarity as that of the developer 8a. Further, a scraping member 12d and an air suction case 12e which suck and remove the toner of the dispersively scattering developer 8a are provided. The developer 8 scatters dispersively over the magnetic poles 12a and the mixed toner 5a and toner 8a are separated from carriers; the electrostatic attracting force by the magnetic poles 12a operates effectively to attract and remove the mixed toner 5a effectively.




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Cited By (2)

    Publication numberPublication dateAssigneeTitle
    JP-S61107275-AMay 26, 1986Toshiba CorpDeveloping device
    JP-S62173481-AJuly 30, 1987Matsushita Electric Ind Co LtdElectrostatic recording device