Patent ID: 6711372
Filing Date: 2004-03-23
Classification: G03G

Abstract:
A developing apparatus for forming a thin layer of toner, comprising:a resilient developing roller for receiving a non-magnetic single-component toner; means for bringing said roller into abutting contact with a surface of an image carrier, whereby toner on the resilient developing roller is supplied to an electrostatic latent image previously formed on the surface of the image carrier, thereby developing the electrostatic latent image; and means for moving the image carrier and the resilient developing roller in a forward direction so that a travelling speed of the image carrier and a peripheral speed of the resilient developing roller become substantially identical, wherein: a width of a development nip zone that extends from a point at which the resilient developing roller starts to contact the image carrier to a point at which the resilient developing roller breaks contact with the image carrier is at least 4 mm, a rubber hardness of the resilient roller is 20 to 40Â° measured according to the JIS K 6253 (Type A) standard and a diameter of the resilient developing roller is within the range 40 to 100 mm, and an amount of bite by which the surface of the image carrier bites into the resilient developing roller is equal to or greater than {fraction (1/100)} of the radius of the resilient developing roller, and the amount of bite and the width of the development nip zone are such that the resilient developing roller breaks contact with the image carrier while a travellng speed of a local portion of the resilient developing roller in contact with the surface of the image carrier gradually decreases from the point at which contact starts and thenceforth gradually returns to the original speed due to resilience of the resilient developing roller.