Development apparatus

Claim 2

An improved electrophotographic printing machine of the type having a photoconductive surface, a corona generating device adapted to charge the photoconductive surface to a substantially uniform charge potential, and an exposure mechanism for exposing the charged photoconductive surface to a light image of the original document to be reproduced to record thereon an electrostatic latent image thereof, wherein the improvement includes: means for depositing toner particles onto the latent image; means for actuating said toner depositing means in response to the latent image advancing to a predetermined location; means, responsive to said toner depositing means being actuated, for moving said toner depositing means from an inoperative position spaced from the latent image to an operative position adjacent thereto; and biasing means for resiliently urging said toner depositing means from the operative position adjacent the latent image to the inoperative position spaced therefrom when said toner depositing is de-energized.

Claim 3

An improved electrophotographic printing machine of the type having a photoconductive surface, a corona generating device adapted to charge the photoconductive surface to a substantially uniform charge potential, and an exposure mechanism for exposing the charged photoconductive surface to a light image of the original document to be reproduced to record thereon an electrostatic latent image thereof, wherein the improvement includes: means for depositing toner particles onto the latent image, said toner depositing means comprising a plurality of developer housings mounted pivotably within the machine, each of said developer housings defining a chamber storing a developer mix comprising carrier granules and toner particles, means, positioned within the chamber of each of said developer housings, for advancing the developer mix from a first region to a second region for discharge thereat rotary driven developer means mounted within the chamber of each of said developer housings closely proximate to said advancing means for receiving the developer mix therefrom, and arranged to deposit toner particles on the latent image when in operative communication therewith, and means for driving selectively said advancing means associated with one of said developer housings such that the reaction torque to the driving moment applied to said advancing means pivots said one of said developer housings disposing said developer means located therein in operative communication with the latent image; means for actuating said toner depositing means in response to the latent image advancing to a predetermined location, whereby said toner depositing means moves from an Inoperative position spaced from the latent image to a position adjacent thereto in operative communication therewith; and biasing means for resiliently urging said toner depositing means from the position adjacent the latent image in operative communication therewith to the inoperative position spaced therefrom.

Claim 4

An improved electrophotographic printing machine of the type having a photoconductive surface, a corona generating device adapted to charge the photoconductive surface to a substantially uniform charge potential, and an exposure mechanism for exposing the charged photoconductive surface to a light image of the original document to be reproduced to record thereon an electrostatic latent image thereof, wherein the improvement includes: means for depositing toner particles onto the latent image, said toner depositing means comprising a plurality of developer housings mounted pivotably within the machine, each of said developer housings defining a chamber storing a developer mix comprising carrier granules and toner particles, means, positioned within the chamber of each of said developer housings, for advancing the developer mix from a first region to a second region for discharge thereat rotary driven developer means mounted within the chamber of each of said developer housings closely proximate to said advancing means for receiving the developer mix therefrom, and arranged to deposit toner particles on the latent image when in operative communication therewith, and means for driving selectively said advancing means associated with one of said developer housings such that the reaction torque to the driving moment applied to said advancing means pivots said one of said developer housings disposing said developer means located therein in operative communication with the latent image; means for actuating said toner depositing means in response to the latent image advancing to a predetermined location, whereby said toner depositing means moves from an Inoperative position spaced from the latent image to a position adjacent thereto in operative communication therewith; and biasing means for resiliently urging said toner depositing means from the position adjacent the latent image in operative communication therewith to the inoperative position spaced therefrom.

Claim 5

A machine as recited in claim 2, wherein said advancing means includes: conveyor means mounted for movement within the chamber of each of said developer housings, and arranged to move the developer mix from a first region to an intermediate region; and rotary driven transport means mounted within the chamber of each of said developer housings, and arranged to move the developer mix from the intermediate region to the second region for discharge thereat.

Claim 6

A machine as recited in claim 3, wherein each of: said transport means includes a first tubular member of non-magnetic material, and first magnetic means fixedly disposed within said first tubular member for creating a magnetic field in the path of the periphery of said first tubular member; and said developer means includes a second tubular member of non-magnetic material, and second magnetic means fixedly disposed within said second tubular member for creating a magnetic field in the path of the periphery of said second tubular member.