US 2009/0214266 A1 · DEVELOPING DEVICE AND IMAGE FORMING APPARATUS

Abstract

The present invention provides a developing device and an image forming apparatus capable of preventing a developer from being discharged excessively using simple configurations in the case that a trickle developing device that uses a two-component developer is in a tilted state. The developing device having stirring members for conveying and stirring a developer and a developer holder, comprises a developer replenishing tank for replenishing the developer to a developer tank and a trickle discharging mechanism, wherein the conveying passages thereof include an upper conveying passage, a lower conveying passage, a first communicating passage for connecting the downstream side of the upper conveying passage to the upstream side of the lower conveying passage, and a second communicating passage for connecting the downstream side of the lower conveying passage to the upstream side of the upper conveying passage, and also include a circulation passage through which the developer circulates using the upper conveying passage, the first communicating passage, the lower conveying passage and the second communicating passage; the discharging mechanism is disposed in the downstream end section of the upper conveying passage; the bottom face on the downstream side of the upper conveying passage is positioned above the bottom face on the upstream side of the lower conveying passage; and the first communicating passage is disposed obliquely downward with respect to the horizontal plane.

Claims20

Dependent claims

A developing device having stirring members for stirring a developer-tank-contained developer containing toner and carrier inside a developer tank while conveying the developer along conveying passages and a developer holder disposed adjacent to said stirring members to supply the stirred developer-tank-contained developer to an electrostatic latent image holder, comprising:

a developer replenishing tank for replenishing the toner and the carrier to said developer tank, and
a discharging mechanism for discharging an excessive amount of the developer-tank-contained developer outside said developer tank from a discharge opening section when the amount of the developer-tank-contained developer to be conveyed using said stirring members inside said developer tank exceeds a predetermined amount, wherein
said stirring members comprises an upper stirring member and a lower stirring member disposed so as to be opposed to said upper stirring member,
said conveying passages include an upper conveying passage in which said upper stirring member is disposed, a lower conveying passage in which said lower stirring member is disposed, a circulating flow outlet provided in a side wall on the downstream side of said upper conveying passage and on the side opposed to said lower conveying passage and a second communicating passage for connecting the downstream side of said lower conveying passage to the upstream side of said upper conveying passage, and also include a circulation passage through which the developer-tank-contained developer circulates using said upper conveying passage, said circulating flow outlet, said lower conveying passage and said second communicating passage,
said discharging mechanism is disposed in the downstream end section of said upper conveying passage, and
said circulating flow outlet is positioned above the level of the developer-tank-contained developer conveyed on the upstream side of said lower conveying passage.

3 more elements

a developer replenishing tank for replenishing the toner and the carrier to said developer tank, and
a discharging mechanism for discharging an excessive amount of the developer-tank-contained developer outside said developer tank from a discharge opening section when the amount of the developer-tank-contained developer to be conveyed using said stirring members inside said developer tank exceeds a predetermined amount, wherein
said stirring members comprises an upper stirring member and a lower stirring member disposed so as to be opposed to said upper stirring member,
said conveying passages include an upper conveying passage in which said upper stirring member is disposed, a lower conveying passage in which said lower stirring member is disposed, a first communicating passage for connecting the downstream side of said upper conveying passage to the upstream side of said lower conveying passage and a second communicating passage for connecting the downstream side of said lower conveying passage to the upstream side of said upper conveying passage, and also include a circulation passage through which the developer-tank-contained developer circulates using said upper conveying passage, said first communicating passage, said lower conveying passage and said second communicating passage,
said discharging mechanism is disposed in the downstream end section of said upper conveying passage,
the bottom face on the downstream side of said upper conveying passage is positioned above the bottom face on the upstream side of said lower conveying passage, and
said first communicating passage is disposed obliquely downward with respect to the horizontal plane.

4 more elements

Dependencies are inferred from the claim text.

Developing device and image forming apparatus

Life of this patent

Developing device and image forming apparatus

Life of this patent

Abstract

Claims20