Magnetic brush developing apparatus for copiers

Claim 2

In a reproduction machine for producing copies of originals having a photoconductive member on which latent electrostatic images of the original being reproduced are formed, with means for developing said latent electrostatic images in preparation for transfer thereof to support material, said developing means including at least one magnetic brush, together with biasing means to provide a biasing voltage on said magnetic brush, the improvement comprising: signal indicator means; energizing means for energizing said signal indicator means to produce a signal; and brush short responsive means responsive to shorting of said magnetic brush to actuate said energizing means whereby to produce said signal.

Claim 3

The reproduction machine according to claim 1 in which said signal indicator means comprises a light.

Claim 4

The reproduction machine according to claim 1 in which said signal indicator means comprises means to shut down said reproduction machine on shorting of said magnetic brush.

Claim 5

The reproduction machine according to claim 1 in which said developing means includes at least two magnetic brushes, said signal indicator means comprising an indicator element for each of said brushes, said short responsive means responding to a short in one of said brushes to actuate said energizing means to energize the indicator element associated with said one brush.

Claim 6

As a control for visually indicating the presence of a short circuit in the magnetic brush developer section of an electrostatic type reproduction machine, said developer section having at least one magnetic developing brush, together with circuit means for imposing an operating bias on said brush, the combination comprising: signal means in said circuit means in series relationship with said magnetic brush; and means responsive to a predetermined change in current in said circuit means to actuate said signal means.

Claim 7

As a control for visually indicating the presence of a short circuit in the magnetic brush developer section of an electrostatic type reproduction machine, said developer section having at least one magnetic developing brush, together with circuit means for imposing an operating bias on said brush, the combination comprising: signal means in said circuit means in series relationship with said magnetic brush; and means responsive to a predetermined change in current in said circuit means to actuate said signal means.

Claim 8

The control according to claim 5 in which said developer section includes plural magnetic brushes, said circuit means providing an individual bias circuit to each of said magnetic brushes, and signal means in each of said magnetic brusH circuits.

Claim 9

In a magnetic brush developing apparatus for reproduction machines, said developing apparatus including a housing within which developing material including bead-like particles of metallic carrier is provided, together with at least one roll-type magnetic brush disposed in operative relationship with said developing material, said magnetic brush being biased whereby to magnetically generate on the surface thereof a blanket-like covering of said developing material for use in developing latent electrostatic images, the combination of: signal producing means; energizing means for energizing said signal producing means to produce a signal; and means responsive to grounding of said magnetic brush through said developing material carrier to actuate said energizing means whereby said signal producing means is energized and a signal reflecting grounding of said brush is produced.

Claim 10

In a magnetic brush developing apparatus for reproduction machines, said developing apparatus including a housing within which developing material including bead-like particles of metallic carrier is provided, together with at least one roll-type magnetic brush disposed in operative relationship with said developing material, said magnetic brush being biased whereby to magnetically generate on the surface thereof a blanket-like covering of said developing material for use in developing latent electrostatic images, the combination of: signal producing means; energizing means for energizing said signal producing means to produce a signal; and means responsive to grounding of said magnetic brush through said developing material carrier to actuate said energizing means whereby said signal producing means is energized and a signal reflecting grounding of said brush is produced.