Electrostatic copying apparatus with combined charging transfer unit

An electrostatic copying apparatus for performing a series of copying functions including at least charging for charging a photosensitive layer, exposure for forming an electrostatic latent image corresponding to the pattern of an original on the charged photosensitive layer, development for turning the electrostatic latent image formed on the photosensitive layer to a visible image, transfer for transferring the visible image formed on the photosensitive layer onto a copying paper, eliminating the electrostatic latent image after the transfer and cleaning for cleaning the photosensitive layer after the elimination of the latent image;

• the copying apparatus comprising a rotatable drum on the circumferential surface of which the photosensitive layer is formed and which makes two rotations for performing the series of the copying functions, a charging-transfer combination unit including means impressed with a voltage of a predetermined level for performing the charging in the first rotation of the rotatable drum and the transfer in the second rotation, said charging-transfer combination unit facing the photosensitive layer of the rotatable drum, an exposure unit performing the exposure in the first rotation of the rotatable drum and facing the photosensitive layer of the rotatable drum, a unit discharging the photosensitive layer for eliminating the electrostatic latent image after the transfer and a development-cleaning combination unit including means for receiving developing powder and means for forming an electromagnetic brush for performing the development in the first rotation of the rotatable drum and the cleaning in the second rotation, said development-cleaning combination unit facing the photosensitive layer of the rotatable drum.

An electrostatic copying apparatus for performing a series of copying functions including at least charging for charging a photosensitive layer, exposure for forming on the photosensitive layer an electrostatic latent image corresponding to the image of an original, development for turning the electrostatic latent image formed on the photosensitive layer to a visible image, transfer for transferring the visible image formed on the photosensitive layer onto a copying paper, eliminating the electrostatic latent image after the transfer and cleaning for cleaning the photosensitive layer;

• the copying apparatus comprising a rotatable drum on the circumferential surface of which the photosensitive layer is formed and which makes two rotations for performing the series of the copying functions, a charging-transfer combination unit having means impressed with a voltage of a predetermined level for performing the charging in the first rotation of the rotatable drum and the transfer in the second rotation, said charging-transfer combination unit facing the photosensitive layer of the rotatable drum, an exposure-electrostatic latent image eliminating combination unit having a single optical means for performing the exposure in the first rotation of the rotatable drum to form the latent image on the rotatable drum and means for directing operatingly the light from said single optical means to the photosensitive layer to eliminate the latent image of the photosensitive layer after the transfer in the second rotation of the rotatable drum, said exposure-electrostatic latent image eliminating unit facing the photosensitive layer of the rotatable drum and a development-cleaning combination unit including means for attaching toner to the electrostatic latent image for the development purpose in the first rotation of the rotatable drum and for electrostatically pulling the residual toner attached to the photosensitive layer for the cleaning purpose after the elimination of the latent image in the second rotation of the rotatable drum, said development-cleaning combination unit facing the photosensitive layer of the rotatable drum.