Electrophotography – Image formation – Development
Reexamination Certificate
2002-09-19
2004-08-17
Brase, Sandra (Department: 2852)
Electrophotography
Image formation
Development
C399S057000, C399S069000, C430S116000, C430S117200
Reexamination Certificate
active
06778799
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Patent Application No. 2002-6506, filed Feb. 5, 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 electrophotographic image forming apparatus, and more particularly, to a liquid electrophotographic image forming apparatus using a developing agent in which a non-volatile ink carrier is used as a solvent.
2. Description of the Related Art
FIG. 1
is a cross-sectional view of a conventional liquid electrophotographic image forming apparatus. Referring to
FIG. 1
, the liquid electrophotographic image forming apparatus includes a photosensitive belt
14
, a charger
15
charging the photosensitive belt
14
, an eraser
17
erasing a residual charge remaining on the photosensitive belt
14
, laser scanning units (LSUs)
16
projecting light onto the charged photosensitive belt
14
and forming a latent electrostatic image, developing units
30
developing the latent electrostatic image, a dryer
18
absorbing and vaporizing a liquid carrier from the photosensitive belt
14
, and a transfer unit
20
transferring the developed latent electrostatic image onto paper
23
.
The photosensitive belt
14
is circulated by a plurality of rollers including a driving roller
11
and passive rollers
12
and
13
. The paper
23
is fed into the transfer unit
20
by rotation of a transfer roller
21
and a fixing roller
22
, and the image is transferred onto the paper
23
.
The LSU
16
scans data related to colors, such as yellow (Y), cyan (C), magenta (M), and black (K), onto the photosensitive belt
14
, and each developing unit
30
supplies a developing solution of a corresponding one of the colors onto the photosensitive belt
14
.
The developing unit
30
includes a developing solution supplier
32
supplying a developing solution onto the photosensitive belt
14
and a developing container
31
capturing the developing solution that drops from the photosensitive belt
14
. The developing container
31
includes a developing roller
36
, a brush roller
37
removing the developing solution that is stained on the developing roller
36
, a squeeze roller
34
separating a liquid carrier that does not form images from the developing solution that is supplied onto the photosensitive belt
14
, and a plate
35
capturing the liquid carrier that is squeezed out of the squeeze roller
34
into the developing container
31
. A collector
39
collects the developing solution.
The developing unit
30
includes the developing roller
36
charged to a predetermined voltage and maintaining a developing gap with the photosensitive belt
14
so that the latent electrostatic images for each color such as Y, C, M, and K, are developed, an injector supplying the developing solution to the developing gap, and the squeeze roller
34
that is placed to apply pressure onto the photosensitive belt
14
. The developing solution includes ink having a concentration where a toner, which s transferred onto the paper
23
to form a print image, is dispersed, and the liquid carrier having a low concentration to transfer the toner to a region where the latent electrostatic image of the photosensitive belt
14
is formed.
The liquid carrier used as a solvent and the ink having a developing material representing one of the colors, such as Y, C, M, and K, are supplied from an ink cartridge
38
to the developing solution supplier
32
. Thus, the developing solution having a proper concentration, in which the liquid carrier is mixed with the ink, is stored in the developing container
31
, and then is supplied to the developing solution supplier
32
. The developing solution supplier
32
supplies the developing solution to the photosensitive belt
14
.
Since the developing solution having a concentration of 2.5-3% is used in the conventional developing unit
30
, the ink having a concentration of 10-30% that is supplied from the ink cartridge
38
is diluted with the liquid carrier having the low concentration and is supplied to the developing unit
30
.
In order to supply the developing solution prepared in the developing supplier
32
to a developing nip formed between the developing roller
36
and the photosensitive belt
14
, the ink is supplied between the developing roller
36
and the photosensitive belt
14
using the developing solution supplier
32
. The developing solution having the low concentration forms the latent electrostatic image on the photosensitive belt
14
, and then the photosensitive belt
14
passes the squeeze roller
34
to remove a surplus liquid carrier from the photosensitive belt
14
. A residual carrier is absorbed into the dryer
18
and is heated, vaporized, captured and compressed by a condenser, and then removed from the photosensitive belt
14
.
The toner having a high concentration and forming an image on the photosensitive belt
14
is transferred to the transfer roller
21
by heat, pressure, or electrostatic force, and part of the residual carrier is vaporized by heat and pressure that is applied to the fixing roller
22
so that the image is retransferred onto the paper
23
, and is thus printed out.
The liquid carrier is used in the conventional image forming apparatus as a liquid developing agent to obtain a high quality image. However, since a flash point of the liquid carrier of the developing solution is less than 80° C., when the developed image having the liquid carrier is fixed at a temperature of more than 110° C., the liquid carrier is vaporized, and then the liquid carrier smells. Thus, in order to prevent the smell of the vaporized liquid carrier, a complex vapor capture system supplying and capturing vapor of the vaporized liquid carrier is required, a volume of the image forming apparatus increases, and a structure of the image forming apparatus becomes complicated. An additional cooler is also required for the condensation of the captured liquid carrier.
In addition, in the conventional liquid eletrophotographic forming apparatus, since the concentration of the liquid developing solution is 2-3% and is different from the concentration of 10-30% of the ink that is provided in the ink cartridge
38
, a complex ink supply system and a concentration controlling apparatus are required to prepare the developing solution having the concentration of 2-3% by mixing the ink having the high concentration with the liquid carrier. Also, a squeeze process is required to remove the surplus liquid carrier remaining in the liquid developing agent having the low concentration.
SUMMARY OF THE INVENTION
To solve the above and other problems, it is an object of the present invention to provide an image forming apparatus, which is capable of preventing a smell caused by vapor of a carrier and also capable of quickly providing a high quality image.
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 liquid electrophotographic image forming apparatus. The apparatus includes a photosensitive body, a charge unit increasing a potential of the photosensitive body to a charge potential, an exposure unit projecting a beam onto the photosensitive body and forming a latent electrostatic image, a developing solution supply unit supplying the photosensitive body with a developing solution having a high concentration where a non-volatile carrier is used as a dispersion solvent, a developing unit to which the developing solution having the high concentration is supplied to form a developing film having the high concentration and to develop the latent electrostatic image, a transfer unit contacting the photosensitive body and moving the developed image from the photosensitive body to a recording medium, and a fixing unit fixing t
Pang Jeong-hun
Shin Kyu-cheol
Song In-yong
Brase Sandra
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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