JPS54103050A - Printer - Google Patents

Abstract

PURPOSE:To prevent a printer from being unabled to accomplish its copying operation or the copy from being blotted thereby to make it possible to accomplish the high speed development by bringing a developing toner apart from a drum or into a developing device to prevent the splash of the toner upon the recording operation of a latent image with the use of the drum rotating at a high speed. CONSTITUTION:Usually, a developing device 3 is held apart from a recording drum 1 and upon a developing roll 101 under the condition having no toner. When the recording mode comes, the drum 1 rotates at a high speed. When the recording operation of the latent image is ended, the drum 1 is braked so that its rotating speed is lowered so that the developing device 3 is changed to its copy mode and is elevated. Then, the roll 101 is turned to bring the toner 31 into contact with the drum 1 thereby to accomplish the development. After a preset number of copies is ended, the device 3 is lowered again. And, the roll 101 is turned in the opposite direction to the development so that the toner on the roll is returned to the device 3. The intensity of the magnetic field of the portion of the roll 101 shown at angle alpha deg. has no power to convey the toner. When the roll 101 is turned counter-clockwise, the toner which has been left above the roll before that time is thrown away to the left.