Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
2002-06-10
2004-07-27
Ngo, Hoang (Department: 2852)
Electrophotography
Image formation
Photoconductive member
C399S120000
Reexamination Certificate
active
06768890
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2001-57653, filed Sep. 18, 2001, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a coupling apparatus to transfer power, and a development cartridge and an electrophotographic printer having the coupling apparatus.
2. Description of the Related Art
Generally, an electrophotographic printer such as a laser printer or a copy machine has a development cartridge for forming an image. The development cartridge has a built-in toner cartridge for supplying toner, which is a development agent, and a rotatable photosensitive drum. The photosensitive drum forms an electrostatic latent image corresponding to a desired image by a light projected from a laser projection unit. In addition, a predetermined image is formed as toner supplied by toner supply means is clung to the formed electrostatic latent image. The toner image formed on the photosensitive drum is transferred to a paper passing through the photosensitive drum and a fixing roller and is printed.
The development cartridge is a disposable article that should be changed when the toner, which is filled inside, is consumed. Therefore, the development cartridge is removably connected with a printer body. Power can be transferred to the development cartridge from a predetermined driving unit of the printer body through a coupling apparatus when the development cartridge is installed in the printer body. In other words, the coupling apparatus for driving the photosensitive drum and a roller for supplying the toner are provided. One example of the conventional coupling apparatus is shown in FIG.
1
.
Referring to
FIG. 1
, the coupling apparatus has a slave coupler
2
disposed at one end of the photosensitive drum
1
of the development cartridge. The coupling apparatus also has a driving coupler
3
disposed in a direction of the driving unit for transferring the driving power to the slave coupler
2
. The slave coupler
2
has bar-type ribs
2
a
that protrude at a predetermined interval of an inner circumference of a cylinder of the slave coupler. Moreover, the driving coupler
3
has bar-type ribs
3
a
that protrude at a predetermined interval at an outer circumference of a cylinder of the driving coupler
3
. Accordingly, when the driving coupler
3
is inserted into the slave coupler
2
, the ribs
3
a
are placed between each of the ribs
2
a
. When the driving coupler
3
is rotated, the ribs
3
a
and
2
a
contact each other, and the driving power of the driving coupler
3
is transferred to the slave coupler
2
, thereby driving the development cartridge.
However, the above coupling apparatus has a gap between the slave coupler
2
and the driving coupler
3
due to errors generated during manufacturing and assembly. Specifically, the gap is generated between an inner diameter of the slave coupler
2
and an outer diameter of the driving coupler
3
. Rotation centers of the couplers
2
and
3
might differ because of the gap. When the couplers
2
and
3
are rotated about different rotation centers, a rotation speed and a rotation force generated from the driving unit are not transferred exactly to the development cartridge. In this case, an accuracy of the image printed on the paper deteriorates as the rotation speed and the rotation force of the photosensitive drum vary.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a coupling apparatus having an improved structure to transmit a rotation power exactly, and a development cartridge, and an electrophotographic printer employing the coupling apparatus.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing a coupling apparatus including a first coupler having a first sloping rib formed at one end, being sloped in a rotation direction, and a second coupler having at least one second sloping rib formed at an inner circumference being sloped corresponding to the first sloping rib. Each sloping rib is relatively connected by being pressed as the first coupler and the second coupler are relatively rotated, and each coupler can be rotated together when each sloping rib is completely connected.
The foregoing and other objects of the present invention are also achieved by providing a development cartridge removably disposed at a printer main body of an electrophotographic printer including a driving motor and a first coupler to transfer a rotation force of the driving motor. The first coupler includes a tapered portion having an outer diameter gradually increasing from one end portion and a first sloping rib being sloped at an outer circumference of the tapered portion. The development cartridge includes a photosensitive drum rotatably disposed at a cartridge frame, and a second coupler disposed at one end of the photosensitive drum, and has an inner diameter that gradually reduces from an outside to an inside corresponding to the tapered portion and a second sloping rib corresponding to the first sloping rib. The first coupler is inserted into the second coupler as the first coupler is rotated, and a rotation force of the driving motor is transferred to the first coupler and the second coupler as the driving motor is rotated.
The foregoing and other objects of the present invention are also achieved by providing an electrophotographic printer including a main body and a development cartridge removably disposed at the main body. The electrophotographic printer further includes a driving motor, a rotation unit rotated by a rotation force transferred from the driving motor, a first coupler movably supported at the rotation unit and having a spiral type first sloping rib at one end, and a removable unit to connect and separate the development cartridge with and from the main body.
The development cartridge includes, a photosensitive drum, a development unit to develop the image on the photosensitive drum, and a second coupler having a second sloping rib for being coupled with the first sloping rib by being spirally formed at an inner circumference corresponding to the first sloping rib and being rotated. The rotation force of the driving motor is transferred from the rotation unit to the photosensitive drum according to a connection by a relative rotation of the first sloping rib and the second sloping rib.
REFERENCES:
patent: 5926673 (1999-07-01), Foster et al.
patent: 6032013 (2000-02-01), Niizawa
patent: 6173146 (2001-01-01), Wang et al.
Cha Douk-soo
Cho Mun-son
Jang Kyung-hwan
Ngo Hoang
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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