US 4,126,100 AGranted

Apparatus for causing a developer powder to make an irregular motion in a developing zone

AssigneeMita Industrial Co., Ltd.

InventorsHitoshi Nishihama, Katsuhiko Gotoda, Minoru Motomura, Takanobu Nakajima, Tatsuo Aizawa

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Abstract

An apparatus for developing an electrostatic latent image formed on the surface of an electrostatic latent image-bearing material by applying a powdery developer, wherein means are provided for bringing the surface of a developer-retaining member retaining a layer of the powdery developer thereon into rolling contact with the surface of the image-bearing material in such a relation that a reservoir zone of the developer is formed at least upstream of the zone of rolling contact between the two surfaces, and means are provided for physically disturbing the developer in the reservoir zone to cause the developer to make an irregular motion.

Claims31

Dependent claims

An apparatus for developing an electrostatic latent image formed on the surface of an image-bearing material by applying a powdery developer thereto, said apparatus comprising a developer-retaining member capable of retaining a layer of the powdery developer on its surface, the surface being movable at a predetermined speed, means for feeding the solid powdery developer to the surface of said developer-retaining member at a predetermined position so that the developer-retaining member can have a layer of the developer on its surface, means for bringing the surface of the developer-retaining member into rolling contact with the surface of the image-bearing material through the layer of the developer at a predetermined position downstream of said first-mentioned predetermined position in the moving direction of the surface of said developer-retaining member, said contacting means bringing the two surfaces into rolling contact with each other in such a relation that a reservoir zone of the developer is formed upstream of and adjacent to the rolling contact zone of the two surfaces, and means for physically disturbing the developer in said reservoir zone to cause the developer to make an irregular motion.

An apparatus for developing an electrostatic latent image formed on the surface of an image-bearing material by applying a powdery developer thereto, said apparatus comprising a hollow cylindrical developer-retaining member rotatable in a predetermined direction, said retaining member having on its surface a relatively insulating coating having a resistance of 10.sup.3 to 10.sup.9 ohms per cm.sup.2 and being kept at a grounded potential;

a magnet having a plurality of poles of opposite polarities arranged alternately on its periphery, said magnet being provided within said developer-retaining member and rotatable independently of said developer-retaining member;
developer-feed means for feeding a relatively conductive one-component developer having a resistivity of not more than 10.sup.13 to the surface of the developer-retaining member at a predetermined position, thereby to retain the developer magnetically on the surface of the developer-retaining member;
and means for bringing the surface of the developer-retaining member into rolling contact with the surface of the image-bearing material through a layer of the developer at a predetermined position downstream of said first-mentioned predetermined position in the rotating direction of the developer-retaining member, said rolling contact means effecting the rolling contact in a predetermined relation so that a reservoir zone of the developer is formed upstream of and adjacent to the rolling contact zone of the two surfaces, and said magnet being rotatable in a direction opposite to the rotating direction of the developer-retaining member to disturb the developer in the reservoir zone physically to cause the developer to make an irregular motion.

Dependencies are inferred from the claim text.