| 摘要 |
PURPOSE:To eliminate a defect in concentration due to the contamination of a developing sleeve by coating a doctor blade with a powdery lubricating agent which is charged electrostatically to the same polarity with toner dispersed in volatile liquid. CONSTITUTION:The elastic body 9b of a doctor blade 9 is coated with the volatile liquid (e.g. fleon 113 and alcohol) 15, wherein the white powdery lubricating particles (e.g. 'Tospearl(R)') 20 of nearly the same size with toner particles are dispersed, by using a brush 14. The toner T and lubricating particles 20 with the same polarity are mixed on the developing sleeve 10 to make the layer thickness of the toner T on the developing sleeve T thin, thereby preventing the lubricating powder 20 from scattering to contaminate the periphery. Thus, the lubricating powder 20 having the same polarity with the toner T is used and then never remains on the developing sleeve 20 for a long time, so the defect in concentration due to the contamination of the developing sleeve 10 is eliminated. |
