Electrophotography – Image formation – Development
Reexamination Certificate
2002-09-10
2003-10-28
Pendegrass, Joan (Department: 2852)
Electrophotography
Image formation
Development
C399S239000
Reexamination Certificate
active
06640074
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application No. 2002-1428, filed Jan. 10, 2002, 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 developing system of a liquid electrophotographic image forming device, and more particularly, to a developing system of a high-concentration liquid electrophotographic image forming device having a developer supplying unit, a developer exhausting unit, and a developer collecting unit.
2. Description of the Related Art
In general, a developing system of a liquid electrophotographic image forming device forms an electrostatic latent image corresponding to a desired image by scanning light on a photosensitive medium, develops the electrostatic latent image using a developer in which powder-shaped toner is mixed with a liquid solvent, and prints the developed image on paper.
FIG. 1
is an example of a conventional developing system of a liquid electrophotographic image forming device disclosed in U.S. Pat. No. 5,255,058.
Referring to
FIG. 1
, the conventional developing system of the liquid electrophotographic image forming device includes a photoconductive drum
10
charged with a predetermined voltage by a photoconductor charging apparatus
14
, an imaging apparatus
16
(laser scanning unit) forming an electrostatic latent image of a desired image by scanning light on the charged photoconductive drum
10
and creating a relative voltage difference representing the electrostatic image, a developer supplying unit developing the electrostatic latent image by supplying a developer to the photoconductive drum
10
, and an intermediate transfer member
30
transferring the developed image of the photoconductive drum
10
and printing the transferred image onto paper
72
.
The developer supplying unit prepares the developer having a concentration of less than 3% solid particles and supplies the developer between the photoconductive drum
10
and a development roller
38
. For this purpose, the developer supplying unit includes concentration cartridges
82
and
84
containing a concentrated developer with a toner concentration of 25% solid, respectively, a solvent cartridge
86
containing a pure solvent, toner reservoirs
55
,
57
,
59
, and
61
mixing the concentrated developer received from the concentration cartridges
82
and
84
with the solvent received from the solvent cartridge
86
and preparing the developer with a uniform concentration of about 2-3% solid particles, a multicolor liquid developer spray assembly
20
pumping the developer prepared in the toner reservoirs
55
,
57
,
59
, and
61
to pumps
90
,
92
,
94
, and
96
, respectively, and supplying the developer to the development roller
38
, and a collecting unit collecting an excess developer left on the photoconductive drum
10
after the electrostatic latent image is developed.
In addition, the collecting unit includes a collection container
50
collecting the developer supplied between the development roller
38
and the photoconductive drum
10
and returning the collected developer to the toner reservoirs
55
,
57
,
59
, and
61
for each color, a squeeze roller
26
pressing the developer against the photoconductive drum
10
on which the image is developed to squeeze the solvent out of the developer contained in the developed image, and a separator
66
collecting the squeezed developer through the collection container
50
, separating respective color toner from the collection container
50
, and returning the solvent to a solvent reservoir
65
.
In the above structure, in order to perform a development operation, the developer having four colors, such as yellow (Y), magenta (M), cyan (C), and black (K), with the concentration of about 2-3% solid particles, is provided in the toner reservoirs
55
,
57
,
59
, and
61
. In order to prepare a developer for each color, the developer supplying unit fabricates a developer with a corresponding concentration by supplying the concentrated developer from the concentration cartridges
82
and
84
and the pure solvent from the solvent cartridge
86
to the toner reservoirs
55
,
57
,
59
, and
61
, respectively. For this purpose, each of the toner reservoirs
55
,
57
,
59
, and
61
measures the concentration of the developer containing the solvent according to a concentration sensor (not shown).
Likewise, when the developer is prepared, the development operation starts. First, the photoconductor charging apparatus
14
charges the photoconductive drum
10
with the predetermined voltage. In this state, the imaging apparatus
16
scans light on the charged photoconductive drum
10
to form the electrostatic latent image of the desired image. Subsequently, the pumps
90
,
92
,
94
, and
96
operate such that the developer provided in the toner reservoirs
55
,
57
,
59
, and
61
is supplied between the development roller
38
and the photoconductive drum
10
through the multicolor liquid developer spray assembly
20
, thereby developing the electrostatic latent image. These charge, exposure, and development operations of four colors, such as yellow (Y), magenta (M), cyan (C), and black (K), are repeatedly and sequentially performed, and thus the developed image for each color is overlapped on the intermediate transfer member
30
. The overlapped color image is printed onto the paper
72
passing through a space between the intermediate transfer member
30
and an impression roller
71
.
However, since a high-concentration developer containing more than 3% solid particles cannot be directly used in the development operation, and a low-concentration developer less than 3% solid is used in the development operation, a structure of the system performing the operations from preparing the developer to supplying and collecting the developer is considerably complicated. Thus, in order to solve the problem, a new developing system of a liquid electrophotographic image forming device is required.
SUMMARY OF THE INVENTION
To solve the above and other problems, it is an object of the present invention to provide a developing system of a high-concentration liquid electrophotographic image forming device having a developer supplying unit, a developer exhausting unit, and a developer collecting unit.
Additional objects and advantageous 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.
Accordingly, to achieve the above and other objects, there is provided a developing system of a liquid electrophotographic image forming device. The developing system includes a developer reservoir in which a developer is stored, a development container to which the developer is supplied from the developer reservoir, a development roller rotating opposite to a photosensitive drum in the development container, and a pumping portion connected between the development container and the developer reservoir via connection pipes to supply the developer to the development container from the developer reservoir, or to exhaust the developer from the development container and return the developer to the developer reservoir.
It is possible that a developer inlet/outlet is formed on a lower portion of the development container and connected to the pumping portion via the connection pipe, and the pumping portion is a tubing pump selectively supplying and exhausting the developer according to a rotational direction of a rotor installed in the pumping portion.
The system may further include a developer collecting unit collecting the developer exceeding a predetermined level in the development container and returning the developer to the developer reservoir.
REFERENCES:
patent: 5255058 (1993-10-01), Pinhas et al.
patent: 6324367 (2001-11-01), Ateya et al.
patent: 6466757 (2002-10-01), Itaya et al.
Pendegrass Joan
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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