Electrophotography – Image formation – Development
Reexamination Certificate
1999-12-23
2001-06-26
Brase, Sandra (Department: 2852)
Electrophotography
Image formation
Development
C399S249000
Reexamination Certificate
active
06253050
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a development apparatus of a liquid electrophotographic printer, and more particularly, to a development apparatus of a liquid electrophotographic printer in which the boundary portion between an image area of a photoreceptor web and a non-image area of an edge portion is prevented from being contaminated.
2. Description of the Related Art
Referring to
FIG. 1
, a typical liquid electrophotographic printer includes a photoreceptor web
10
circulating while being supported by a plurality of support rollers (not shown). The photoreceptor web
10
has an image area D
1
corresponding to a development roller
11
to which a development electrical potential V
D
of a predetermined level is applied during development, and a non-image area D
2
provided at both edge portions of the image area D
1
.
The photoreceptor web
10
is initialized as the entire surface thereof is charged to an electrical potential V
0
. A laser scanning unit (LSU)(not shown) scans light to the photoreceptor web
10
according to image signals so that a portion of the image area D
1
is charged to an image electrical potential V
I
to form an electrostatic latent image area D
1
′.
The electrostatic latent image area D
1
′ is developed as it passes the development roller
11
. That is, developer adhering to the outer circumferential surface of the development roller
11
is transferred to the photoreceptor web
10
due to the difference in electrical potential between a development electrical potential V
D
of the development roller
11
and the image electrical potential V
I
of the photoreceptor web
10
so that an electrostatic latent image is developed. Developer in the electrostatic latent area is pressed by a squeegee roller
13
so that toner of the developer becomes filmy and the other liquid carrier is removed from the photoreceptor web
10
.
Here, the development roller
11
constantly maintains the development electrical potential V
D
. Thus, as the development roller
11
and the image area D
1
of the photoreceptor web
10
having different electrical potential levels face each other, the electrical potential V
O
of the image area D
1
is changed to a balanced electrical potential V
E
according to the charge balance principle as shown in the drawing. Such a state causes a difference in electrical potential at a boundary line A between the image area D
1
and the non-image area D
2
, that is, both edge portions of the image area D
1
are developed by the developer remaining on the photoreceptor web
10
. Thus, the developer at the boundary line A is pressed by the squeegee roller
13
and firmly remains on the photoreceptor web
10
, to thus contaminate the photoreceptor web
10
.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide a development apparatus of a liquid electrophotographic printer having an improved structure so that the boundary line between the image area and the non-image area of a photoreceptor web is prevented from being developed.
Accordingly, to achieve the above objective, there is provided a development apparatus of a liquid electrophotographic printer which includes a photoreceptor web having an image area where an electrostatic latent image is formed and a non-image area at both sides of the image area, a development roller is installed to correspond to the image area to which a development electrical potential of a predetermined level is applied and where developer is supplied to the electrostatic latent image, a squeegee roller for removing developer remaining on the photoreceptor web, and an air injection nozzle, installed adjacent to both ends of the development roller, for injecting air to move developer remaining on the photoreceptor web from the non-image area to the image area so that a boundary line between the image area and the non-image area is prevented from being developed due to a difference in electrical potential therebetween.
It is preferred in the present invention that the development apparatus of a liquid electrophotographic printer further includes an auxiliary air injection nozzle installed adjacent to both ends of the squeegee roller for injecting air to move developer remaining on the photoreceptor web from the non-image area to the image area.
REFERENCES:
patent: 3741643 (1973-06-01), Smith et al.
patent: 4259006 (1981-03-01), Phillips et al.
patent: 4793281 (1988-12-01), Dobbins et al.
patent: 5157443 (1992-10-01), Anderson et al.
patent: 5481342 (1996-01-01), Arcaro et al.
patent: 5793400 (1998-08-01), Mukoyama et al.
patent: 5805963 (1998-09-01), Teschendorf et al.
Brase Sandra
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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