Electrophotographic device

Claim 2

An electrophotographic device, characterized by gradually closing and gradually opening circuits for application of electric potential to the developing electrode so as to synchronize the application of electric potential with the relative movement of a sheet-shaped insulating material with respect to the developing electrode, whereby electric field will be generated only at the portion of the aforementioned developing electrode confronting the sheet-shaped insulating material while making a relative movement with reference thereto to cause the toner in the liquid developing agent to flow in the direction of the sheet-shaped insulating material.

Claim 3

An electrophotographic device as claimed in claim 1, wherein the developing electrode is divided into smaller portions in the direction perpendicular to the direction in which the sheet is advanced.

Claim 4

An electrophotographic device as claimed in claim 2, wherein said portions of the developing electrode are applied to the same potential.

Claim 5

An electrophotographic device as claimed in claim 3, wherein later portions of the divided developing electrode are applied to decreased potential.

Claim 6

An electrophotographic device which comprises a detector which detects the entry of a sheet-shaped material provided in the path of the sheet-shaped insulating material to a development station including a deveLoping electrode divided into smaller portions in the direction perpendicular to the direction in which the sheet is advanced, closing and opening circuits for application of electric potential to the portions of the developing electrode, and a delay circuit which receives the signal from said detector and makes said circuits close so as to apply electric potential only to the portions of the electrode confronting the sheet-shaped insulating material.

Claim 7

An electrophotographic device which comprises a detector which detects the entry of a sheet-shaped material provided in the path of the sheet-shaped insulating material to a development station including a deveLoping electrode divided into smaller portions in the direction perpendicular to the direction in which the sheet is advanced, closing and opening circuits for application of electric potential to the portions of the developing electrode, and a delay circuit which receives the signal from said detector and makes said circuits close so as to apply electric potential only to the portions of the electrode confronting the sheet-shaped insulating material.

Claim 8

An electrophotographic device as claimed in claim 5, wherein said delay circuit comprises a magnetic recording tape carried synchronously with the transportation of the sheet, a magnetic recording head confronting said recording tape and excited by the signal from the detector, and plurality of heads which read the signal on the tape and put out the signal to close and open said circuits for application of electric potential to the portion of the developing electrode.

Claim 9

In an electrophotographic device comprising a container for a liquid developer having toner particles dispersed therein, and means including a carrier for moving a sheet of insulating material through said container, the improvement comprising a development electrode divided into a plurality of portions oriented perpendicular to the direction of movement of said sheet; detecting means for sensing the presence of said sheet along its path of movement; at least one source of potential; and actuating means responsive to said detecting means for sequentially energizing said development electrode means as said sheet is moved adjacent the successively energized development electrode portions and for sequentially de-energizing said development electrode portions as said sheet is moved away from the successively de-energized development electrode portions whereby said source of potential is only applied to those development electrode portions which are adjacent the sheet as it moves adjacent the development electrode so that the toner is substantially deposited only on the sheet and not the carrier therefor.

Claim 10

In an electrophotographic device comprising a container for a liquid developer having toner particles dispersed therein, and means including a carrier for moving a sheet of insulating material through said container, the improvement comprising a development electrode divided into a plurality of portions oriented perpendicular to the direction of movement of said sheet; detecting means for sensing the presence of said sheet along its path of movement; at least one source of potential; and actuating means responsive to said detecting means for sequentially energizing said development electrode means as said sheet is moved adjacent the successively energized development electrode portions and for sequentially de-energizing said development electrode portions as said sheet is moved away from the successively de-energized development electrode portions whereby said source of potential is only applied to those development electrode portions which are adjacent the sheet as it moves adjacent the development electrode so that the toner is substantially deposited only on the sheet and not the carrier therefor.

Claim 11

The improvement as in claim 7 where said detecting means is disposed a predetermined distance from said development electrode, said improvement including delay means for delaying the output from said detecting means until the forward end of said sheet reaches the first of said plurality of development electrode portions.

Claim 12

The improvement as in claim 8 where said delay means includes a movable storage medium, the output from said detecting means being recorded thereon, and where said actuating means includes (1) a plurality of switching means connected between said potential source and said plurality of development electrode portions respectively and (2) a plurality of sensing means successively disposed along a portion of said movable storage medium and respectively connected to said plurality of switching means, the first of said sensing means being disposed a predetermined distance from where the output from said detecting means is recorded on said movable storage medium and distance between said sensing means corresponding to the distance between said development electrode portions.

Claim 13

The improvement as in claim 7 including a plurality of potential sources respectively associated with said development electrode portions, the potential sources being of successively smaller magnitude as the associated development electrode portions are more removed from the first development electrode portion to encounter the sheet.