Electrophotography – Cleaning of imaging surface – Having handling of removed material
Reexamination Certificate
2002-02-15
2004-03-23
Braun, Fred L (Department: 2852)
Electrophotography
Cleaning of imaging surface
Having handling of removed material
C399S120000
Reexamination Certificate
active
06711374
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a developing cartridge for use in an image forming apparatus such as a copying machine, a facsimile apparatus, or a printer.
2. Description of the Related Art
As a toner cartridge for use in an image forming apparatus such as a copying machine, a facsimile apparatus, or a printer, there has conventionally been proposed a toner cartridge comprising: a toner replenishing port for supplying unused toner to a developing apparatus; an unused toner accommodating portion communicating with the toner replenishing port; a collecting port for collecting waste toner, i.e. left-over toner collected by a cleaner of an image forming apparatus after image transfer process; a waste toner accommodating portion for receiving waste toner, which communicates with the collecting port; and a partitioning wall for parting the unused toner accommodating portion from the waste toner accommodating portion, wherein the unused toner accommodating portion and the waste toner accommodating portion are formed integrally with each other.
However, such a conventional toner cartridge as described above has the following disadvantage. When an amount of waste toner to be collected by the cleaner of the image forming apparatus exceeds the capacity of the waste toner accommodating portion due to occurrence of unexpected usage and environmental conditions, the waste toner accommodating portion is filled to capacity and is thus no longer capable of receiving waste toner.
To solve such a problem, Japanese Unexamined Patent Publication JP-A 4-237079 (1992) discloses a technique embodied as an image forming unit in which an unused toner accommodating portion and a waste toner accommodating portion are formed integrally with each other. In this construction, even if the amount of the collected waste toner exceeds the capacity of the waste toner accommodating portion, the waste toner accommodating portion is protected against damage without the waste toner accommodating portion being increased in size more than necessary. That is, in the partitioning wall located between the unused toner accommodating portion and the waste toner accommodating portion is provided an opening portion having a shutter which opens under the pressure of waste toner to be accommodated in the waste toner accommodating portion. This arrangement causes waste toner in excess of the capacity of the waste toner accommodating portion to flow into the unused toner accommodating portion.
Moreover, Japanese Unexamined Patent Publication JP-R 8-44179 (1996) proposes a toner cartridge which allows effective use of unused toner and effective use of a space of a waste toner accommodating portion. This toner cartridge has such a structure that an unused toner accommodating portion and a waste toner accommodating portion are formed integrally with each other, and is provided with a pair of toner conveying members formed so as to penetrate through a partitioning wall for parting the unused toner accommodating portion from the waste toner accommodating portion.
By the rotation of the toner conveying member, within the unused toner accommodating portion, unused toner is conveyed toward a replenishing port so as to drop into a developing apparatus. This makes possible effective use of unused toner. On the other hand, within the waste toner accommodating portion, waste toner collected from a collecting port formed in the waste toner accommodating portion is conveyed toward the partitioning wall, located away from the immediately below of the collecting port, and is then stored. This makes possible effective use of a space of the waste toner accommodating portion.
However, these prior art techniques have the following disadvantages. The toner cartridge disclosed in JP-A 4-237079 is so designed that waste toner in excess of the capacity of the waste toner accommodating portion is dropped in a free-fall fashion into the unused toner accommodating portion. In this publication, the whereabouts of the opening portion for allowing waste toner to flow into the unused toner accommodating portion is merely described as a position as far away from a developing roller, which is disposed within the developing apparatus, as possible, and no mention is made as to a specific opening portion formation position on the basis of the amount of the waste toner to be produced. Furthermore, in the toner cartridge, the opening/closing action of the shutter disposed in the opening portion is dependent solely upon pressure from waste toner stored in the waste toner accommodating portion. Therefore, in a case where produced waste toner is unexpectedly increased in quantity due to the influence of the usage and environmental conditions, it is impossible to convey the waste toner to the unused toner accommodating portion in accordance with the amount of the waste toner produced, resulting in failure of proper control of the amount of the waste toner stored in the waste toner accommodating portion. That is, it is impossible to control an amount of waste toner to be conveyed from the waste toner accommodating portion to the unused toner accommodating portion.
On the other hand, in the toner cartridge disclosed in JP-A8-44179, the waste toner accommodating portion and the unused toner accommodating portion are formed integrally with each other, and coaxially within each of the toner accommodating portions is disposed conveying means for dispersing toner evenly. However, this construction, though having the technical advantage in that the waste and unused toner accommodating portions have a common conveying means driving source, is not intended for moving waste toner from the waste toner accommodating portion to the unused toner accommodating portion. Therefore, in a case where waste toner is increased in quantity due to the usage condition or other factors, in order for the entire amount of the waste toner produced to be stored in the waste toner accommodating portion without causing damage to the waste toner accommodating portion, the waste toner accommodating portion needs to have an unduly large size.
SUMMARY OF THE INVENTION
An object of the invention is to provide a developing cartridge used with one-component and dual-component developer, in which developer can be fed from a transfer residual developer accommodating portion to an unused developer accommodating portion without the transfer residual developer accommodating portion being increased in size more than necessary, and an amount of developer to be moved can be controlled properly. Another object of the invention is to provide an image forming apparatus employing said developing cartridge.
The invention provides a developing cartridge comprising:
a housing including a first accommodating portion for accommodating developer yet to be used in development, and a second accommodating portion for accommodating developer having been used in development, the second accommodating portion being arranged adjacent to the first accommodating portion; and
conveying means having a conveying member, for conveying, when an amount of developer to be stored in the second accommodating portion exceeds a predetermined level, the developer from the second accommodating portion to the first accommodating portion, the conveying means being so formed as to extend over the first and second accommodating portions.
According to the invention, the conveying means having a conveying member is so formed as to extend over the first and second accommodating portions. When an amount of developer to be stored in the second accommodating portion exceeds a predetermined level, the conveying means conveys the developer from the second accommodating portion to the first accommodating portion. In this arrangement, when transfer residual developer collected after image development process is increased in quantity and consequently an amount of developer to be stored in the second accommodating portion exceeds a predetermined level, the developer is conveyed from the second accommodating p
Funayama Naotaka
Nagata Tsutomu
Sanada Yoshiaki
Yamaguchi Jun
Birch & Stewart Kolasch & Birch, LLP
Braun Fred L
Sharp Kabushiki Kaisha
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