To enable the high-speed electrographic printing of excellent quality by separating the surface of a development roller from the surface of a doctor roller by the gap larger than the mean diameter of the toner particles.
A gap between the surface of a doctor roller 6 and the surface of a development roller 2 is slightly larger than the diameter of the toner particles 5. The toner particles 5 which are separate particles of non-conductive material of the general size of approximately 5-15 μm are carried to the doctor roller 6 in a plurality of layers by the development roller 2. Only the toner particles 5 of the limited number are passed through a narrow gap between the development roller 2 and the doctor roller 6 at the position of the doctor roller 6. Because the gap is extreme-slightly larger than the diameter of the toner particles 5, and only the toner particles 5 of one layer are correctly passed through gap the between the development roller 2 and the doctor roller 6. Thus, a forming area to collect the toner particles 5 in front of the gap is stable in size.
SCHOENFELD CARSTEN DR
BARTSCHER GERHARD
CORMIER STEVE
FRASER KENNETH D
RODI ANTON
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