Patent ID: 7231154
Filing Date: 2007-06-12
Classification: G03G

Abstract:
1. A developing apparatus for developing an electrostatic image formed on an image bearing member with toner, said apparatus comprising: a developing container for containing a developer including toner and carrier, said developing container being partitioned by a partition wall into a first chamber and a second chamber, wherein said first chamber and said second chamber are in fluid communication with each other at opposite end portions thereof; a first feeding member, provided in said first chamber, for feeding the developer within said developing container; a second feeding member, provided in said second chamber, for feeding the developer in a direction opposite a feeding direction of said first feeding member; a developer carrying member for carrying the developer to a position where said developer carrying member is opposed to said image bearing member; supplying means for supplying a developer including toner and carrier into said first chamber through a supply opening; supply controlling means for controlling a supplying operation of said supplying means to control a toner content of the developer in said developing container, a discharging outlet, provided in said first chamber, for discharging an excessive part of the developer in said developing container resulting from a supplying operation of said supplying means to an outside of said developing container; wherein said discharging outlet is disposed upstream of said supply opening with respect to the developer feeding direction of said first feeding member; an amount of the developer in said developing container is 100–2000 (g), an angle of rest of the developer in said developing container is 20–70 (°), wherein when said developing apparatus develops an electrostatic image having an image density of 100(%), an amount A (g) of the developer in said developing container at the time when a difference between a carrier supply amount per unit time by said supplying means and a carrier discharging amount per unit time through the discharging outlet becomes 5 (g/min) or less, and an amount B (g) of the developer in said developing container at the time the carrier discharging amount per unit time becomes 0.5 (g/min) or less when said developing apparatus operates without supply of the carrier by said supplying means, satisfy: