Developing device for copier and others

Claim 3

A device as claimed in claim 1, further comprising sensor means for sensing arrival of said shield member at each of said first and second positions.

Claim 4

A device as claimed in claim 1, further comprising shield member stopping means for stopping said shield member at each of said first and second positions.

Claim 5

A device as claimed in claim 1, wherein said magnetic field developing means comprises a main pole magnetic body for development located to face said latent image carrier, and auxiliary pole magnetic bodies for scooping the developer onto said sleeve.

Claim 6

A device as claimed in claim 4, wherein said main pole magnetic body is located in a position outside of a region which is defined between said first and second positions.

Claim 7

A device as claimed in claim 1, further comprising non-magnetic, shield member support means disposed between said magnetic field developing means and said shield member for supporting said shield member.

Claim 8

A device as claimed in claim 6, wherein said shield member support means is made of oreoresin.

Claim 9

A device as claimed in claim 6, wherein said shield member support means supports said shield member at at least an intermediate and a free end portion of said shield member.

Claim 10

A device as claimed in claim 6, wherein said magnetic field developing means comprises magnetic bodies in a form of blocks, said shield member support means supporting said blocks.

Claim 11

A developing unit located in close proximity to a latent image carrier of an image forming apparatus, comprising: magnetic brush forming means for forming a magnetic brush means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means.

Claim 12

A developing unit located in close proximity to a latent image carrier of an image forming apparatus, comprising: magnetic brush forming means for forming a magnetic brush means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means.

Claim 13

A developing unit as claimed in claim 10, further comprising scoop control means for controlling an amount of developer which is scooped by said scooping means.

Claim 14

A developing unit as claimed in claim 11, wherein said scoop control means reduces the amount of developer while said developing unit is not operated for development.

Claim 15

A developing unit as claimed in claim 10, wherein said magnetic field developing means comprises a main pole magnetic body for development located to face said latent image carrier, and auxiliary pole magnetic bodies for scooping the developer onto said sleeve.

Claim 16

A developing unit as claimed in claim 13, wherein said main pole magnetic body is located in a position outside of a region which is defined between said first and second positions.

Claim 17

A developing unit as claimed in claim 10, wherein said scooping means comprises a rotary paddle roller.

Claim 18

A developing unit as claimed in claim 15, wherein said paddle roller is located at a position and rotated at a speed which prevent the developer from being transported to an uppermost portion of said sleeve when said shield member shields the magnetic field at said first position.

Claim 19

In a developing device having at least one developing unit which is located in close proximity to a latent image carrier of an image forming apparatus, said developing unit comprising magnetic brush developing means for developing a magnetic brush by carrying a developer on said magnetic brush forming means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means.

Claim 20

In a developing device having at least one developing unit which is located in close proximity to a latent image carrier of an image forming apparatus, said developing unit comprising magnetic brush developing means for developing a magnetic brush by carrying a developer on said magnetic brush forming means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means.

Claim 21

A developing unit as claimed in claim 17, wherein said magnetic field developing means comprises a main pole magnetic body for development located to face said latent image carrier, and auxiliary pole magnetic bodies for scooping the developer onto said sleeve.

Claim 22

A developing unit as claimed in claim 18, wherein said main pole magnetic body is located in a position outside of a region which is defined between said first and second positions.

Claim 23

In a multiple color developing device having a plurality of developing units which are located in close proximity to a latent image carrier of an image forming apparatus, each of said developing units comprising magnetic brush forming means for forming a magnetic brush by carrying a developer on said magnetic brush developing means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means. PG,39

Claim 24

In a multiple color developing device having a plurality of developing units which are located in close proximity to a latent image carrier of an image forming apparatus, each of said developing units comprising magnetic brush forming means for forming a magnetic brush by carrying a developer on said magnetic brush developing means, said magnetic brush forming means comprising a cylindrical sleeve for supporting said magnetic brush on an outer periphery of said cylindrical sleeve, magnetic field developing means disposed in said sleeve for developing magnetic fields for forming said magnetic brush, and a shield member located in a space which is defined between said sleeve and said magnetic field developing means such that said shield member is movable in a reciprocal motion between a first position corresponding to that where said sleeve scoops the developer and a second position corresponding to that where said developer is separated, said shield member shielding a part of said magnetic fields at said first and second positions, and scooping means for supplying the developer to said first position on said sleeve of said magnetic brush forming means. PG,39

Claim 25

A developing unit as claimed in claim 20, wherein said magnetic field developing means comprises a main pole magnetic body for development located to face said latent image carrier, and auxiliary pole magnetic bodies for scooping the developer onto said sleeve.

Claim 26

A developing unit as claimed in claim 21, wherein said main pole magnetic body is located in a position outside of a region which is defined between said first and second positions.