US 4,791,455 A · Color electrophotographic apparatus and method of cleaning a photosensitive medium

Abstract

A cleaning device for use in a color electrophotographic apparatus in which a photosensitive medium is made to rotate for a plurality of times so as to conduct repetitional cycles each including charging, exposure and development, thereby forming toner images of different colors on the photosensitive medium. The cleaning device comprises a conductive fur brush for cleaning the surface of the photosensitive medium so as to remove any toner remaining on the surface of the photosensitive medium; and a driving mechanism for placing the fur brush in contact with the photosensitive medium during cleaning and for keeping the same away from the photosensitive medium when the cleaning is not conducted. The cleaning device effectively prevents any part of the toner after the transfer from remaining on the surface of the photosensitive medium.

Claims17

Dependent claims

A color electrophotographic apparatus, comprising:

a photosensitive medium;
a main corona-charger for applying a charge to said photosensitive medium before exposure thereof;
exposure means for exposing said photosensitive medium after a charge is applied thereto by said main corona-charger;
a plurality of developing units each having toner of a different color for developing toner images on said photosensitive medium with toner in different colors;
an image transfer unit for transferring a toner image formed on said photosensitive medium;
a fur brush which is electrically conductive for cleaning the surface of said photosensitive medium;
a drive mechanism for moving said fur brush into contact with said photosensitive medium during cleaning and for moving said fur brush out of contact with said photosensitive medium when cleaning is not conducted;
a D.C. power supply for supplying a D.C. voltage to said fur brush;
and
a corona-charger disposed upstream of said fur brush but downstream of said image transfer unit, for applying a charge to said photosensitive medium after the transfer of the toner images so that toner remaining on said photosensitive medium is uniformly corona-charged.

7 more elements

A method of cleaning a photosensitive medium in a color electrophotographic apparatus in which said photosensitive medium is adapted to be rotated and subjected to repetitions of toner image formation in different colors, said apparatus further comprising a corona-charger for applying a charge to said photosensitive medium;

exposure means for exposing said photosensitive medium;
a plurality of developing units each having toner of different colors for developing toner images on said photosensitive medium with said toner of different colors an image transfer unit for transferring thus developed toner images from said photosensitive medium onto an image bearing medium;
a fur brush which is electrically conductive for cleaning said photosensitive medium;
an electrical power source for applying a voltage to said fur brush;
means for collecting toner from said fur brush;
and cleaning means including a mechanism for moving said fur brush into contact with said photosensitive medium during a period of cleaning said photosensitive medium and for moving said fur brush out of contact with said photosensitive medium during a period other than the cleaning period, said method of cleaning a photosensitive medium comprising the steps of:
applying a corona-charge to said photosensitive medium after said toner images are transferred from said photosensitive medium to said image bearing medium so that toner remaining on said photosensitive medium is charged with a uniform polarity;
and
cleaning said photosensitive medium after same has been corona-charged, by means of said fur brush by applying a D.C. voltage to said fur brush using said electrical power source and contacting said fur brush with said photosensitive medium by means of said mechanism for moving said fur brush.

6 more elements

Dependencies are inferred from the claim text.

Color electrophotographic apparatus and method of cleaning a photosensitive medium

Life of this patent

Color electrophotographic apparatus and method of cleaning a photosensitive medium

Life of this patent

Abstract

Claims17