Electrographic development apparatus and method having oscillating magnetic cross-mixing

Claim 2

In electrographic development apparatus of the kind adapted for use at a development zone which extends transversely across the operative path of an electrographic imaging device, said development apparatus including means providing a developer supply zone and magnetic brush means for transporting developer along a developer path from said supply zone into a developing position at the development zone and then back toward the developing position or the supply, the improvement comprising: (a) cross-mix magnet means mounted proximate a transverse portion of said developer path; and (b) means for oscillating said cross-mix magnet means along said developer path portion whereby developer moving past said portion of said developer path is intermixed transversely across said developer path.

Claim 3

In electrographic development apparatus of the kind adapted for use at a development zone which extends transversely across the operative path of an electrographic imaging device, said development apparatus including a developer housing providing a supply zone for electrographic developer and magnetic feed means for transporting developer along a developer path from said supply zone to a developing position at the development zone and then back toward the supply zone, the improvement comprising: (a) a non-magnetic housing portion extending transversely of, and in closely spaced relation to, said developer path at a location displaced from said developing position; (b) cross-mix magnet means mounted in close relation to said non-magnetic housing portion and on the housing side external with respect to the developer path; and (c) means for oscillating said cross-mix magnet means along said non-magnetic housing portion whereby developer moving along the developer path will be shifted transversely with respect to the operative path of the electrographic imaging device.

Claim 4

In electrographic development apparatus of the kind adapted for use at a development zone which extends transversely across the operative path of an electrographic imaging device, said development apparatus including a developer housing providing a supply zone for electrographic developer and magnetic feed means for transporting developer along a developer path from said supply zone to a developing position at the development zone and then back toward the supply zone, the improvement comprising: (a) a non-magnetic housing portion extending transversely of, and in closely spaced relation to, said developer path at a location displaced from said developing position; (b) cross-mix magnet means mounted in close relation to said non-magnetic housing portion and on the housing side external with respect to the developer path; and (c) means for oscillating said cross-mix magnet means along said non-magnetic housing portion whereby developer moving along the developer path will be shifted transversely with respect to the operative path of the electrographic imaging device.

Claim 5

The invention defined in claim 2 wherein cross-mix magnet means includes a plurality of spaced magnets mounted for oscillating movements respectively along different sectors of said non-magnetic housing portion.

Claim 6

The invention defined in claim 2 or 3 wherein said non-magnetic housing portion includes a plurality of magnetic shunt means spaced along its transversing dimension whereby the magnetic attraction of developer by said cross-mix magnet means is intermittently interrupted during such oscillating movement.

Claim 7

In electrographic development apparatus of the kind adapted for use at a development zone which extends transversely across the operative path of an electrographic imaging device, said apparatus including (1) a rotatable magnetic brush means for transporting developer along a developer path from a supply zone into a developing position at the development zone and then back to the developing position or the supply zone and (2) a developer housing for substantially enclosing said magnetic brush, said supply zone and said developer path except at said development zone, the improvement comprising: (a) a non-magnetic housing portion extending transversely of, and in closely spaced relation to, a portion of the developer path which is downstream of said developing position; (b) cross-mix magnet means mounted in close relation to said non-magnetic housing portion and on the housing side external with respect to said magnetic brush and supply zone; and (c) means for oscillating said cross-mix magnet means along said non-magnetic housing portion in a manner such that developer moving past said downstream position is substantially intermixed, transversely across said developer path.

Claim 8

In electrographic development apparatus of the kind adapted for use at a development zone which extends transversely across the operative path of an electrographic imaging device, said apparatus including (1) a rotatable magnetic brush means for transporting developer along a developer path from a supply zone into a developing position at the development zone and then back to the developing position or the supply zone and (2) a developer housing for substantially enclosing said magnetic brush, said supply zone and said developer path except at said development zone, the improvement comprising: (a) a non-magnetic housing portion extending transversely of, and in closely spaced relation to, a portion of the developer path which is downstream of said developing position; (b) cross-mix magnet means mounted in close relation to said non-magnetic housing portion and on the housing side external with respect to said magnetic brush and supply zone; and (c) means for oscillating said cross-mix magnet means along said non-magnetic housing portion in a manner such that developer moving past said downstream position is substantially intermixed, transversely across said developer path.

Claim 9

The invention defined in claim 5 wherein cross-mix magnet means includes a plurality of spaced magnets mounted for oscillating movement along different sectors of said non-magnetic housing portion.

Claim 10

The invention defined in claim 5 or 6 wherein said non-magnetic housing portion includes a plurality of magnetic shunt means spaced along its transversing dimension whereby the magnetic attraction of said cross-mix magnet on developer is intermittently interrupted during such oscillating movements.

Claim 11

The invention defined in claim 5 or 6 further including means located on said developer path, between said developing position and said non-magnetic housing portion, for skiving developer from said magnetic brush.

Claim 12

In a method of electrographic development which includes magnetically attracting a developer from the supply portion of a developer housing, transporting the attracted developer along a developer path into a developing relation with an electrographic imaging member and back toward such supply portion, the improvement comprising attracting the developer transported along the developer path with a magnetic field which oscillates transversely across the operative developer path.

Claim 13

In a method of electrographic development which includes magnetically attracting a developer from the supply portion of a developer housing, transporting the attracted developer along a developer path into a developing relation with an electrographic imaging member and back toward such supply portion, the improvement comprising attracting the developer transported along the developer path with a magnetic field which oscillates transversely across the operative developer path.

Claim 14

In a method of electrographic development which includes magnetically attracting a toner-carrier developer mixture from the supply portion of a developer housing, transporting the attracted developer mixture, within said housing, into a developing relation with an electrographic imaging member and then back toward said supply portion, the improvement comprising attracting the toner and carrier mixture flowing along the return path with a magnetic field which is generated external of the developer housing and oscillates transversely across the developer path.

Claim 15

In a method of electrographic development which includes magnetically attracting a toner-carrier developer mixture from the supply portion of a developer housing, transporting the attracted developer mixture, within said housing, into a developing relation with an electrographic imaging member and then back toward said supply portion, the improvement comprising attracting the toner and carrier mixture flowing along the return path with a magnetic field which is generated external of the developer housing and oscillates transversely across the developer path.