Developing device

Claim 2

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a casing for containing a developer, said casing having an outlet at one end thereof; an endless movable developer carrier for carrying the developer thereon, said developer carrier being disposed in said casing outlet; means for charging the developer, said charging means comprising a cylindrical resilient body rotatably mounted in said casing in confronting relation to the developer carrier; means for transferring and coating the charged developer as a layer onto said developer carrier under an electric field; means for limiting the thickness of said layer of developer on said developer carrier to a prescribed thickness; and a swingable resilient sheet having one end fixedly mounted in said casing and the other end held in contact with the outer circumferential surface of said cylindrical resilient body, said swingable resilient sheet being vibratable under its own resiliency on rotation of said cylindrical resilient body; said transferring and coating means and said thickness limiting means being successively disposed in the direction in which said developer carrier moves; and said charging means, said transferring and coating means and said developer carrier being arranged such that only the developer which passes through said charging means is supplied to said developer carrier.

Claim 3

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a casing containing developer therein and provided with an outlet; an endless movable developer carrier arranged in the outlet of the casing for carrying the developer thereon; a rotatable cylindrical charging body arranged within the casing so that a portion of the casing surrounds part of the cylindrical charging body and adjacent the developer carrier for charging the developer and supplying charged developer adjacent the developer carrier, the developer carrier being arranged between the cylindrical charging body and the outlet of the casing, the cylindrical charging body being arranged between the developer carrier and the developer contained within the casing, the developer carrier and the cylindrical charging body being movable in a common direction at a position where the developer carrier and the cylindrical charging body are in contact, the peripheral speed of the cylindrical charging body being higher than the peripheral speed of the developer carrier, the cylindrical charging body being operative to transfer the charged developer to the developer carrier and to coat the charged developer as a layer on said developer carrier, and the part of the cylindrical resilient body which is surrounded by the casing rotating in a direction from a bottom of the casing toward the developer carrier; and means for limiting the thickness of said layer of the developer on said developer carrier to a prescribed thickness, said thickness limiting means being arranged downstream of the position where the developer is transferred from the cylindrical charging body to the developer carrier with respect to the direction in which the developer carrier moves.

Claim 4

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a casing containing developer therein and provided with an outlet; an endless movable developer carrier arranged in the outlet of the casing for carrying the developer thereon; a rotatable cylindrical charging body arranged within the casing so that a portion of the casing surrounds part of the cylindrical charging body and adjacent the developer carrier for charging the developer and supplying charged developer adjacent the developer carrier, the developer carrier being arranged between the cylindrical charging body and the outlet of the casing, the cylindrical charging body being arranged between the developer carrier and the developer contained within the casing, the developer carrier and the cylindrical charging body being movable in a common direction at a position where the developer carrier and the cylindrical charging body are in contact, the peripheral speed of the cylindrical charging body being higher than the peripheral speed of the developer carrier, the cylindrical charging body being operative to transfer the charged developer to the developer carrier and to coat the charged developer as a layer on said developer carrier, and the part of the cylindrical resilient body which is surrounded by the casing rotating in a direction from a bottom of the casing toward the developer carrier; and means for limiting the thickness of said layer of the developer on said developer carrier to a prescribed thickness, said thickness limiting means being arranged downstream of the position where the developer is transferred from the cylindrical charging body to the developer carrier with respect to the direction in which the developer carrier moves.

Claim 5

The developing device of claim 2, wherein developer carried on the developer carrier and the latent image carrier are out of contact with each other.

Claim 6

The developing device of claim 2, further comprising means for applying a DC electric field between the developer carrier and the latent image carrier.

Claim 7

The developing device of claim 2, further comprising a partition extending at a position downstream, with respect to a direction of rotation of the cylindrical resilient body, of the position where the cylindrical resilient body and the developer carrier oppose each other, the partition preventing uncharged developer from reaching the position where the cylindrical resilient body and the developer carrier oppose each other.

Claim 8

The developing device of claim 2, further comprising: a scraper plate held in slidable contact with the cylindrical resilient body for scraping off an excessive amount of the developer from the cylindrical resilient body and uniformly providing the developer on the cylindrical resilient body.

Claim 9

The developing device of claim 2, wherein the developer carrier and the cylindrical resilient body are made of electrically conductive material, and wherein the developing device comprises means for applying an electric potential between the developer carrier and the cylindrical resilient body.

Claim 10

The developing device of claim 7, wherein the electric potential includes a superposition of an AC voltage and a DC voltage.

Claim 11

The developing device of claim 2, wherein the developer carrier and the cylindrical resilient body are made of electrically conductive material, and wherein the developing device further comprises means for applying an electric potential between the developer carrier and the cylindrical resilient body, and means for sensing a current caused by the application of the electric potential.

Claim 12

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a movable endless developer carrier carrying a developer thereon, the developer carrier opposing the latent image carrier; a rotatable cylindrical resilient body contacting the outer circumferential surface of the developer carrier, the developer carrier and the cylindrical resilient body being movable in a common direction at a position where the developer carrier and the cylindrical resilient body are in contact, the peripheral speed of the cylindrical resilient body being higher than the peripheral speed of the developer carrier; means for limiting a layer of the developer to a prescribed thickness, the developer layer extending on the developer carrier in a region downstream, with respect to a direction of movement of the developer carrier, of a position where the developer carrier and the cylindrical resilient body oppose each other, and upstream of a position where the developer carrier and the latent image carrier oppose each other; means for supplying the developer to an outer circumferential surface of the cylindrical resilient body at a position distant from the position where the developer carrier and the cylindrical resilient body oppose each other; and a casing accommodating the developer and the supplying means, wherein a portion of the casing surrounds part of the outer circumferential surface of the cylindrical resilient body extending between the supplying means and the developer carrier and wherein the part of the cylindrical resilient body which is surrounded by the casing rotates in a direction from a bottom of the casing toward the developer carrier.

Claim 13

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a movable endless developer carrier carrying a developer thereon, the developer carrier opposing the latent image carrier; a rotatable cylindrical resilient body contacting the outer circumferential surface of the developer carrier, the developer carrier and the cylindrical resilient body being movable in a common direction at a position where the developer carrier and the cylindrical resilient body are in contact, the peripheral speed of the cylindrical resilient body being higher than the peripheral speed of the developer carrier; means for limiting a layer of the developer to a prescribed thickness, the developer layer extending on the developer carrier in a region downstream, with respect to a direction of movement of the developer carrier, of a position where the developer carrier and the cylindrical resilient body oppose each other, and upstream of a position where the developer carrier and the latent image carrier oppose each other; means for supplying the developer to an outer circumferential surface of the cylindrical resilient body at a position distant from the position where the developer carrier and the cylindrical resilient body oppose each other; and a casing accommodating the developer and the supplying means, wherein a portion of the casing surrounds part of the outer circumferential surface of the cylindrical resilient body extending between the supplying means and the developer carrier and wherein the part of the cylindrical resilient body which is surrounded by the casing rotates in a direction from a bottom of the casing toward the developer carrier.

Claim 14

The developing device of claim 10, wherein the developer carried on the developer carrier and the latent image carrier are out of contact with each other.

Claim 15

The developing device of claim 10, further comprising means for applying a DC electric field between the developer carrier and the latent image carrier.

Claim 16

The developing device of claim 10, further comprising a partition extending at a position downstream, with respect to a direction of rotation of the cylindrical resilient body, of the position where the cylindrical resilient body and the developer carrier oppose each other, the partition preventing uncharged developer from reaching the position where the cylindrical resilient body and the developer carrier oppose each other.

Claim 17

The developing device of claim 10, further comprising a scraper plate held in slidable contact with the cylindrical resilient body for scraping off an excessive amount of the developer from the cylindrical resilient body and uniformly providing the developer on the cylindrical resilient body.

Claim 18

The developing device of claim 10, wherein the developer carrier and the cylindrical resilient body are made of electrically conductive material, and wherein the developing device further comprises means for applying an electric potential between the developer carrier and the cylindrical resilient body.

Claim 19

The developing device of claim 15, wherein the electric potential includes a superposition of an AC voltage and a DC voltage.

Claim 20

The developing device of claim 10, wherein the developer carrier and the cylindrical resilient body are made of electrically conductive material, and wherein the developing device further comprises means for applying an electric potential between the developer carrier and the cylindrical resilient body, and means for sensing a current caused by the application of the electric potential.

Claim 21

The developing device of claim 10, wherein the limiting means comprises a blade having first and second ends, the first end forming a pivot and the second end being in press contact with the developer carrier, the pivot being positioned to drive the blade toward the developer carrier by a frictional force acting on the second end during movement of the developer carrier, the second end having a projection.

Claim 22

The developing device of claim 10, wherein the limiting means comprises a blade having first and second ends, the first end forming a pivot and the second end being in press contact with the developer carrier, the pivot being positioned to drive the blade away from the developer carrier by a frictional force acting on the second end during movement of the developer carrier, the second end having a projection.

Claim 23

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a casing accommodating a developer, an end of the casing having an outlet; an endless developer carrier positioned at the outlet of the casing and carrying the developer thereon; a rotatable cylindrical resilient body contacting an outer circumferential surface of the developer carrier; means for limiting a layer of the developer to a prescribed thickness, the developer layer extending on the developer carrier in a region downstream, with respect to a direction of movement of the developer carrier, of a position where the developer carrier and the cylindrical resilient body oppose each other; and a resilient sheet extending in the casing and having first and second ends, the first end being fixed to the casing, the second end engaging the developer, the resilient sheet driving the developer toward the cylindrical resilient body.

Claim 24

A developing device for visualizing a latent electrostatic image formed on a latent image carrier, comprising: a casing accommodating a developer, an end of the casing having an outlet; an endless developer carrier positioned at the outlet of the casing and carrying the developer thereon; a rotatable cylindrical resilient body contacting an outer circumferential surface of the developer carrier; means for limiting a layer of the developer to a prescribed thickness, the developer layer extending on the developer carrier in a region downstream, with respect to a direction of movement of the developer carrier, of a position where the developer carrier and the cylindrical resilient body oppose each other; and a resilient sheet extending in the casing and having first and second ends, the first end being fixed to the casing, the second end engaging the developer, the resilient sheet driving the developer toward the cylindrical resilient body.

Claim 25

A developing device for visualizing a latent electrostatic image formed on a latent carrier, comprising: a casing accommodating a developer, an end of the casing having an outlet; an endless developer carrier positioned at the outlet of the casing and carrying the developer thereon; a rotatable cylindrical resilient body contacting an outer circumferential surface of the developer carrier; and a resilient sheet extending in the casing and having first and second ends, the first end being fixed to the casing, the second end engaging the developer, the resilient sheet swinging in response to rotation of the cylindrical resilient body.

Claim 26

A developing device for visualizing a latent electrostatic image formed on a latent carrier, comprising: a casing accommodating a developer, an end of the casing having an outlet; an endless developer carrier positioned at the outlet of the casing and carrying the developer thereon; a rotatable cylindrical resilient body contacting an outer circumferential surface of the developer carrier; and a resilient sheet extending in the casing and having first and second ends, the first end being fixed to the casing, the second end engaging the developer, the resilient sheet swinging in response to rotation of the cylindrical resilient body.