Electrophotography – Image formation – Development
Reexamination Certificate
1999-06-24
2001-04-10
Braun, Fred L. (Department: 2852)
Electrophotography
Image formation
Development
C399S350000
Reexamination Certificate
active
06215972
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for cleaning a squeeze roller of a liquid printer, and more particularly, to an apparatus for cleaning a squeeze roller of a liquid printer in which the structure of a blade is improved to improve the efficiency in cleaning and extend the life span of the blade.
2. Description of the Related Art
A liquid electrophotographic printer prints an image by forming an electrostatic latent image by scanning a laser beam on a photosensitive medium, developing the image with a developer including toner of a predetermined color using a developing unit and transferring the developed image to a print medium.
The liquid electrophotographic printer, as shown in
FIG. 1
, includes a laser scanning unit (LSU) for forming an electrostatic latent image on a photosensitive medium
10
and a developing unit
20
for forming an image corresponding to the electrostatic latent image.
The developing unit
20
includes a developing vessel
21
and a developing roller
23
which is disposed to face the photosensitive medium
10
such that a predetermined gap G exists therebetween. The apparatus further includes a cleaning roller
25
for removing developer adhering to the outer circumferential surface of the developing roller
23
and an injector
27
for injecting developer containing toner and a carrier into the gap G is a squeeze roller
29
for separating the toner and the carrier by closely pressing the photosensitive medium
10
, and a squeeze roller cleaning apparatus
30
for cleaning off the developer adhering to the squeeze roller
29
when a drip-line is removed.
The conventional squeeze roller cleaning apparatus
30
, as shown in
FIG. 2
, includes a blade
31
contacting the outer circumferential surface of the squeeze roller
29
slanted at a predetermined angle. The apparatus further includes, a blade holder
33
fixedly holding the blade
31
, and a spanking mechanism
35
for removing a holding volume Vh of the developer remaining between the blade
31
and the squeeze roller
29
by allowing the blade holder
33
to repeatedly pivot a plurality of times. As shown in
FIG. 3
, the blade
31
is formed of a single rubber member. To prevent a phenomenon in which a surface of a leading edge
31
a
of the blade
31
contacts the squeeze roller
29
since the blade
31
bends excessively by the rotation of the squeeze roller
29
(hereinafter, referred to as the overturn of the blade), the blade
31
is disposed in a trailing direction with respect to the rotational direction of the squeeze roller
29
in a drip-line removing mode.
To embody the above squeeze roller cleaning apparatus, in the developing unit
20
, the pressing force and rotational direction of the squeeze roller
29
varies according to each of a home position, a development mode, and a drip-line removing mode. In the development mode, the pressing force between the squeeze roller
29
and a squeeze backup roller
29
′ is greatest and the squeeze roller
29
rotates in the direction the photosensitive medium
10
rotates by being passively rotated by the photosensitive medium
10
. The squeeze roller
29
squeezes and separates most of the carrier from the developer adhering to the photosensitive medium
10
so as to form a film of the developer. In this mode, the blade
31
is disposed to be separated from the squeeze roller
29
.
In the drip-line removing mode, a relatively weak force is applied between the squeeze roller
29
and the squeeze backup roller
29
′ compared to the development mode and the squeeze roller
29
rotates in a direction opposite to that which the photosensitive medium
10
proceeds. The blade
31
contacts the squeeze roller
29
and cleans the carrier adhering to the squeeze roller
29
.
The squeeze roller cleaning apparatus for the conventional liquid printer having the above structure has the following disadvantages.
First, since a rubber member vulnerable to abrasion is adopted, the blade requires replacement after printing about 10,000 sheets of paper.
Second, since the blade is disposed in the trailing direction to prevent the overturn of the blade, the holding volume is generated due to the developer remaining between the blade and the squeeze roller so that the efficiency in cleaning is lowered.
Third, since a spanking mechanism for removing the holding volume is needed, the number of parts and the number of assembly steps increases.
SUMMARY OF THE INVENTION
To solve the above problems, it is an objective of the present invention to provide an apparatus for cleaning a squeeze roller of a liquid printer. The apparatus includes a blade having a structure which prevents overturn of a contact portion thereof when a squeeze roller rotates so that, by controlling the arrangement of the blade, the life span of the blade can be prolonged, formation of a holding volume can be prevented, and a spanking mechanism is not needed.
Accordingly, to achieve the above objective, there is provided an apparatus for cleaning a squeeze roller of a liquid printer by which developer adhering to an outer circumferential surface of the squeeze roller. The squeeze roller is used for forming a film of the developer formed of toner and liquid carrier by pressing the developer onto a photosensitive medium. The apparatus is comprised of a blade holder and a blade. The blade comprises a plate having predetermined rigidity and a cover member having a weaker rigidity than the plate and is coated on or adhering to an outer surface of the plate. One end of the blade being fixedly coupled to the blade holder and an opposite end thereof contacting the outer circumferential surface of the squeeze roller, wherein the blade is disposed to be slanted in a trail counter direction with respect to a rotational direction of the squeeze roller in a drip-line removing mode so that the developer adhering to the squeeze roller can be removed.
REFERENCES:
patent: Re. 30924 (1982-05-01), Katayama et al.
patent: 4568175 (1986-02-01), Inowa et al.
patent: 5043769 (1991-08-01), Osawa et al.
patent: 5153659 (1992-10-01), Maiefski et al.
patent: 5321483 (1994-06-01), Yokoyama et al.
patent: 5363182 (1994-11-01), Kuribayashi et al.
patent: 5937250 (1999-08-01), Kwak et al.
patent: 5987297 (1999-11-01), Kimoto et al.
An Hyung-jin
Kim Kyeong-hwan
Braun Fred L.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
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