Developing method using non-magnetic one-component toner and developing unit therefor

Claim 1

A developing unit for developing an electrostatic latent image formed on a photoreceptor drum surface with non-magnetic, one-component toner composition comprising in combination: a conveyor unit for transporting non-magnetic, single component toner particles therein, said conveyor unit including a fur brush means for electrically charging said toner particles by friction; a photoreceptor drum for forming an electrostatic latent image on the surface thereof having an electrically attracting force; a hollow cylinder connected with said conveyor unit juxtapositioned to and facing said photoreceptor drum into which said single component toner particles are conveyed, said hollow cylinder including a fur brush means therein for further charging said single component toner particles by friction and for mechanically stirring said toner particles to create a cloud-like state of said toner particles, said hollow cylinder comprising a surface portion having toner passages formed in at least that portion of said surface portion facing said photoreceptor drum surface; means for applying a bias voltage to said hollow cylinder to assist said fur brush means in stirring said toner particles and creating said cloud-like state of said toner particles, a screen grid mounted in a zone between said hollow cylinder and said photoreceptor drum through which said charged toner particles must pass in the development of said electrostatic latent image; and means for applying an AC bias voltage to said screen grid to cause said toner particles to fly about after emerging from said hollow cylinder to be selectively deposited on said electrostatic latent image.

Claim 8

A method of developing an electrostatic latent image on a photoreceptor drum which comprises: providing a photoreceptor drum having an electrostatic latent image formed on the surface thereof; providing non-magnetic, single-component toner particles in a conveyor for transporting said toner particles; friction charging said toner particles by means of a fur brush while in said conveyor; introducing said charged toner particles into a hollow cylinder connected to said conveyor, juxtapositioned to a photoreceptor drum, said hollow cylinder being provided with a fur brush means for further friction charging said toner particles and toner passages formed in at least a surface portion of said cylinder facing said photoreceptor drum to permit passage of said toner particles therethrough; agitating said toner particles within said hollow cylinder both mechanically and electrically, by mechanically stirring by said fur brush and electrically stirring by applying a charge to said cylinder thereby maintaining said particles in a cloud like state; providing a screen grid to a zone between said hollow cylinder and said photoreceptor drum where said cylinder is in said facing relationship with said photoreceptor drum; applying an AC bias to said screen grid so as to impart a flying state to said toner particles as said particles emerge from said cylinder through said toner passages into said zone under the effect of an electrostatic field created by said electrostatic latent image; and developing said electrostatic latent image, said charged toner particles being selectively deposited from said flying state of said toner particles on said electrostatic latent image.

Claim 9

A method of developing an electrostatic latent image on a photoreceptor drum which comprises: providing a photoreceptor drum having an electrostatic latent image formed on the surface thereof; providing non-magnetic, single-component toner particles in a conveyor for transporting said toner particles; friction charging said toner particles by means of a fur brush while in said conveyor; introducing said charged toner particles into a hollow cylinder connected to said conveyor, juxtapositioned to a photoreceptor drum, said hollow cylinder being provided with a fur brush means for further friction charging said toner particles and toner passages formed in at least a surface portion of said cylinder facing said photoreceptor drum to permit passage of said toner particles therethrough; agitating said toner particles within said hollow cylinder both mechanically and electrically, by mechanically stirring by said fur brush and electrically stirring by applying a charge to said cylinder thereby maintaining said particles in a cloud like state; providing a screen grid to a zone between said hollow cylinder and said photoreceptor drum where said cylinder is in said facing relationship with said photoreceptor drum; applying an AC bias to said screen grid so as to impart a flying state to said toner particles as said particles emerge from said cylinder through said toner passages into said zone under the effect of an electrostatic field created by said electrostatic latent image; and developing said electrostatic latent image, said charged toner particles being selectively deposited from said flying state of said toner particles on said electrostatic latent image.