Electrophotography – Image formation – Development
Reexamination Certificate
2003-03-04
2004-08-10
Grimley, Arthur T. (Department: 2852)
Electrophotography
Image formation
Development
Reexamination Certificate
active
06775500
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2002-40667, filed Jul. 12, 2002, in the Korean Intellectual 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 liquid image forming system, the structure of which is simplified using a high-concentration developing agent, and a method of forming an image using the same.
2. Description of the Related Art
In general, liquid image forming systems radiate light onto a photosensitive body, form an electrostatic latent image corresponding to a desired image on the photosensitive body, develop the electrostatic latent image with a developing agent in which toner in powder form is mixed with a liquid solvent, and then prints the image onto a piece of paper.
FIG. 1
shows the structure of a conventional liquid image forming system disclosed in U.S. Pat. No. 5,255,058.
As shown in
FIG. 1
, the conventional liquid image forming system includes a photosensitive body
10
charged to a predetermined potential by a charger
14
, a light scanning unit (LSU)
16
which radiates light onto the charged photosensitive body
10
, forms a relative potential difference thereon, and forms an electrostatic latent image corresponding to a desired image, a developing agent-supplying unit which supplies a developing agent to the photosensitive body
10
to form the electrostatic latent image, and a transfer body
30
which transfers the image developed on the photosensitive body
10
and prints the image onto a piece of paper
72
.
In general, the developing agent-supplying unit prepares a developing agent with a toner concentration of less than 3% solid and supplies the developing agent between the photosensitive body
10
and a developing roller
38
. To do this, the developing agent-supplying unit includes concentrated cartridges
82
and
84
, in which a concentrated developing agent of about 25% solid is dipped, and a solvent cartridge
86
in which a pure solvent is stored. The development agent-supplying unit also includes mixing tanks
55
,
57
,
59
, and
61
which mix the concentrated cartridges
82
and
84
with the solvent to prepare a developing agent with a uniform concentration of about 2-3% solid, a supplying unit
20
which pumps the developing agent prepared in the mixing tanks
55
,
57
,
59
, and
61
to pumps
90
,
92
,
94
, and
96
and supplies the developing agent to the developing roller
38
, and a withdrawing unit which withdraws the developing agent remaining after a developing operation. The withdrawing unit includes a collecting container
50
which collects the developing agent flowing after being supplied between the developing roller
38
and the photosensitive body
10
and returns the collected developing agent to the mixing tanks
55
,
57
,
59
, and
61
for each color, a squeeze roller
26
which presses the photosensitive body
10
on which an image is developed, and squeezes a solvent contained in the developed image, and a separator
66
which withdraws the squeezed developing agent from the collecting container
50
, separates the toner from the developing agent, and returns a solvent to a solvent tank
65
.
In the above structure, in order to perform a developing operation, developing agents having four colors such as yellow (Y), magenta (M), cyan (C), and black (K), with a uniform concentration of 2-3% solid, are prepared in each of the mixing tanks
55
,
57
,
59
, and
61
, respectively. Of course, only one developing agent is prepared in a system to perform a development operation using a single color such as a black-and-white image. However, a system in which four-color developing agents are prepared so as to implement color images is disclosed here. In order to prepare developing agents for each color, the developing agent-supplying unit supplies the concentrated developing agent and the pure solvent to the mixing tanks
55
,
57
,
59
, and
61
from the concentrated cartridges
82
and
84
and the solvent cartridge
86
, thereby manufacturing a developing agent with a predetermined concentration. For this purpose, in general, a concentration sensor (not shown) is provided in each of the mixing tanks
55
,
57
,
59
, and
61
and measures the concentration of the mixed developing agent. In this way, if developing agents are prepared for each color, the developing operation begins. First, the charger
14
charges the photosensitive body
10
to a predetermined potential. In this state, the LSU
16
radiates light onto the charged photosensitive body
10
, reduces a potential thereon, thereby forming an electrostatic latent image corresponding to a desired image. Subsequently, the pumps
90
,
92
,
94
, and
96
operate and supply the developing agents prepared in the mixing tanks
55
,
57
,
59
, and
61
between the developing roller
38
and the photosensitive body
10
via the supplying unit
20
, thereby developing the electrostatic latent image. The developed image is transferred onto the transfer body
30
. If the image is an image formed of one color, the image is directly printed on the paper
72
. However, if a color image is implemented with a plurality of overlapped color developing agents, an image developed for each color is overlapped on the transfer body
30
by repeating charge, exposure, and development operations for four colors such as yellow (Y), magenta (M), cyan (C), and black (K). The overlapped color image is printed on the paper
72
passing between the transfer roller
30
and a compressing roller
71
.
However, as described above, the structure of the liquid image forming system requiring the operations of preparing, supplying, and withdrawing the developing agent, is very complicated. This is because a concentrated high-concentration developing agent cannot be used, but instead a low-concentration developing agent of less than 3% solid is used during the developing operation. Of course, if the developing agent is manufactured with a low-concentration and is used during the developing operation, mobility is improved, and a difference in toner density for each portion of the developed image is reduced. However, as described above, the conventional liquid image forming system requires a very complicated structure. Specifically, the concentrated developing agent and the solvent are dipped in the concentrated cartridges
82
and
84
and the solvent cartridge
86
, respectively, are transferred to the mixing tanks
55
,
57
,
59
, and
61
, and are mixed with a low-concentration developing agent of less than 3% solid for development to thereby form an electrostatic latent image. Then, the solvent contained in the developed image is squeezed and withdrawn to be in a high-concentration state suitable for printing. Thus, the size of the liquid image forming system or costs are increased.
In addition, since a transfer operation of an image formed of a low-concentration developing agent is performed, even after a squeezing operation is completed, liquid may easily flow out due to a pressure applied during the transfer operation. Thus, it is quite possible that an image may be spread or dragged. Accordingly, in order to obtain a clear image, the transfer roller
30
should have a special structure having a humidity-absorption layer. Also, an additional image-drying apparatus, which prevents the image from spreading during the transfer operation by drying an image, should be further provided. Also, if the image-drying apparatus is installed, the temperature in a printer is greatly increased. Thus, in order to prevent deterioration of the performance of the photosensitive body
10
, a cooler should be further installed.
Hence, a new liquid image forming system that can solve the above problems is required.
SUMMARY OF THE INVENTION
Accordingly, it is an aspect of the present invention to provide a liquid image forming system having an improved structure, in which a high-concentration developing agent is used withou
Gleitz Ryan
Grimley Arthur T.
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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