Developing apparatus using a developer carrier capable of forming microfields

A developing device for developing a latent image electrostatically formed on an image carrier by supplying a developer from a developer carrier to a developing region at which said developer carrier faces said image carrier, comprising a developer carrier having a plurality of surface portions, each of said surface portions having a particular characteristic, and wherein at least one of said surface portions is charged to deposit a charge thereon while the other surface portion is charged to a polarity opposite to and in an amount corresponding to a charge of said at least one of said surface portions by charge injection caused by electrostatic induction ascribable to said charge of said at least one of said surface portions to thereby deposit a charge thereon, thereby forming microfields between said charges, and wherein said at least one of said surface portions is made of a substance chargeable by friction and capable of holding a charge while said other surface portion is made of a substance charge injectable and having electrostatic capacity allowing the charge to be deposited in said amount, whereby a charged developer is carried on said surface portions by use of said microfields.

A developing device for developing a latent image electrostatically formed on an image carrier by supplying a developer from a developer carrier to a developing region at which said developer carrier faces said image carrier, comprising a developer carrier having a plurality of surface portions, each of said surface portions having a particular characteristic, and wherein at least one of said surface portions is charged by friction to deposit a charge thereon while the other surface portion is connected to ground and charged to a polarity opposite to and in an amount corresponding to a charge of said at least one of said surface portions by charge injection caused by electrostatic induction ascribable to said charge of said at least one of said surface portions to thereby deposit a charge thereon, thereby forming microfields between said charges, whereby a charged developer is carried on said surface portions by use of said microfields.

A developer carrier for carrying a developer on a surface thereof, wherein said developer carrier has a plurality of surface portions, each of said surface portions having a particular characteristic, and wherein at least one of said surface portions is charged to deposit a charge thereon while the other surface portion is charged to a polarity opposite to and in an amount corresponding to a charge of said at least one of said surface portions by charge injection caused by electrostatic induction ascribable to said charge of said at least one of said surface portions to thereby deposit a charge thereon, thereby forming microfields between said charges, whereby a charged developer is carried on said surface portions by use of said microfields.

A developer carrier for carrying a developer on a surface thereof, wherein said developer carrier has a plurality of surface portions, each of said surface portions having a particular characteristic, and wherein at least one of said surface portions is charged by friction to deposit a charge thereon while the other surface portion is connected to ground and charged to a polarity opposite to and in an amount corresponding to a charge of said at least one of said surface portions by charge injection caused by electrostatic induction ascribable to said charge of said at least one of said surface portions to thereby deposit a charge thereon, thereby forming microfields between said charges, whereby a charged developer is carried on said surface portions by use of said microfields.

A developer carrier for carrying a developer on a surface thereof, wherein said developer carrier has a plurality of surface portions, each of said surface portions having a particular characteristic, and wherein at least one of said surface portions is charged to deposit a charge thereon while the other surface portion is charged to a polarity opposite to and in an amount corresponding to a charge of said at least one of said surface portions by charge injection caused by electrostatic induction ascribable to said charge of said at least one of said surface portions to thereby deposit a charge thereon, thereby forming microfields between said charges, and wherein said at least one of said surface portions is made of a substance chargeable by friction and capable of holding a charge while said other surface portion is made of a substance charge injectable and having electrostatic capacity allowing the charge to be deposited in said amount, whereby a charged developer is carried on said surface portions by use of said microfields.