Powder sprayer with pneumatic powder supply system

A powder sprayer comprising

• a housing for containing a quantity of powder, said housing having an elongated discharge opening,
• a rotatable roller disposed within said opening for metering the discharge of powder from said housing through said discharge opening,
• a powder supply hopper remote from said housing,
• first and second conduits communicating between said powder supply hopper and housing,
• a selectively operable blower connected to one of said conduits,
• said first and second conduits, blower, housing and supply hopper defining a closed loop through which air and powder may be circulated upon operation of said blower for transferring powder from said supply hopper to said housing for maintaining a quantity of powder in the housing for metering by said roller,
• said supply hopper having a discharge opening, means defining a mixing chamber for receiving powder from said supply hopper discharge opening,
• said first conduit having one end connected to said mixing chamber for directing an air flow generated by said blower forcefully against powder within said mixing chamber for causing said powder to become air borne and for generating a relatively rich air powder mixture within said mixing chamber, and
• said second conduit communicating with an upper portion of said mixing chamber for receiving air borne powder in said mixing chamber for direction to said housing.

In a printing press having means for transferring sheet material along a predetermined path, a powder sprayer for directing anti-offset powder onto said sheet material, said powder sprayer comprising

• a housing for containing a quantity of powder, said housing having an elongated discharge opening,
• a rotatable roller disposed within said opening for metering the discharge of powder from said housing through said discharge opening,
• a powder supply hopper remote from said housing,
• conduit means connecting said powder supply hopper to said housing,
• a selectively operable blower connected to said conduit means,
• said conduit means, blower, housing, and supply hopper defining a closed loop through which air and powder may be circulated upon operation of said blower for transferring powder from said supply hopper to said housing for maintaining a quantity of powder in the housing for metering by said roller,
• said supply hopper having a discharge opening, means defining a mixing chamber for receiving powder from said supply hopper discharge opening,
• said conduit means including a first conduit having one end connected to said mixing chamber for directing an air flow generated by said blower forcefully against powder within said mixing chamber for causing said powder to become air borne and for generating a relatively rich air powder mixture within said mixing chamber, and
• said conduit means including a second conduit communicating with an upper portion of said mixing chamber for receiving air borne powder in said mixing chamber for direction to said housing.