Powder cloud xerographic development apparatus

Claim 2

A powder cloud generator comprising: a powder carrier having a plurality of apertures passing therethrough, a porous support beneath each of said apertures, each porous support and each of said apertures defining a plurality of cavities into which a metered amount of powdered material can be deposited, means for applying a metered amount of said powdered material into each of said cavities, means for entraining the metered powdered material deposited in each cavity in a gaseous fluid passing through said porous support, said entraining means comprising a pickup tube positioned adjacent a cavity passing therebelow, and means for intermittently rotating said powder carrier means, each aperture in said powder carrier means passing during rotation beneath said metering means and said entraining means, said intermittent rotation means positioning sequentially each cavity filled with powdered material beneath said pickup tube during the periods when said powder carrier means is not being rotated.

Claim 3

The powder cloud generator of claim 3 wherein said entraining means is successively pulsed each time a cavity having a metered amount of powder material therein passes below said pickup tube.

Claim 4

A powder cloud generator comprising: powder carrier means having at least one aperture passing therethrough, porous support means beneath each aperture, each aperture and its associatEd porous support means defining a cavity into which a unit charge of powdered material can be deposited, means to meter a unit charge of powdered material into each defined cavity, aspirator means having its pickup end positioned adjacent the upper surface of each cavity as each cavity is positioned therebeneath, said aspirator means entraining the unit charge of powdered material deposited in said cavity by said metering means in a gaseous fluid drawn through said porous support means during the operation thereof, and means for intermittently rotating said powder carrier means, each aperture in said powder carrier means passing during rotation beneath said metering means and said aspirator means, said intermittent rotation means positioning sequentially each cavity filled with powdered material beneath said pickup end during the periods when said powder carrier means is not being rotated.

Claim 5

The powder cloud generator of claim 5 wherein said means for intermittently rotating said powder carrier means comprises Geneva wheel means.

Claim 6

A powder cloud generator comprising powder carrier means having at least one aperture passing therethrough; porous support means beneath each aperture; said porous support means and each aperture defining a cavity into which a unit charge of powdered material can be deposited; means to meter a unit charge of powdered material into each of said cavities; aspirator means including a pickup tube having a pickup and an output end, said pickup end positioned adjacent the upper surface of each cavity as each cavity is positioned therebeneath, an aspirator tube having an output end operatively positioned adjacent the output end of said pickup tube, the passage of a first gaseous fluid through said aspirator tube causing the unit charge of powdered material metered into said cavity to be entrained in a second gaseous fluid drawn through said porous support means and into said pickup tube, said entrained powdered material being drawn out of the output end of said pickup tube and blown, by continued flow of said first gaseous fluid through said aspirator tube, through a port adjacent the output ends of said aspirator and pickup tubes; and means for intermittently rotating said powder carrier means, each aperture in said powder carrier means passing sequentially during rotation beneath said metering means and said aspirator means, said intermittent rotation means sequentially positioning a cavity filled with powdered material beneath said aspiration means during the periods when said powder carrier means is not being rotated.

Claim 7

The powder cloud generator of claim 7 further including means for causing said first gaseous fluid to be passed through said aspirator tube for a period of time such that substantially all of the powdered material within the cavity positioned beneath said pickup tube is entrained, whereby said pickup tube is substantially cleaned of residual powdered material by the continued suction of said second gaseous fluid through said porous support means and said pickup tube.

Claim 8

The powder cloud generator of claim 7 further including gasket means disposed about the end of said pickup tube; and means to urge said gasket means and the end of said pickup tube into frictional engagement with that portion of the upper surface of said powder carrier means immediately adjacent that cavity positioned beneath said pickup tube; said frictional engagement serving to prevent the entrainment of powdered material from sources other than the cavity immediately beneath said pickup tube during aspiration.

Claim 9

The powder cloud generator of claim 7 wherein said means for intermittently rotating said powder carrier means comprises Geneva wheel means.