Wet-type image forming device and cleaning apparatus

Details Wet-type image forming device and cleaning apparatus Wet-type image forming device and cleaning apparatus

2000-10-13

2001-11-13

Beatty, Robert (Department: 2852)

Electrophotography

Cleaning of imaging surface

Removing liquid developer

C399S249000

Reexamination Certificate

active

06317578

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to wet-type image forming devices and to electrophotographic apparatuses. More specifically, the present invention relates to a wet-type image forming device which employs electrophotography to render visible, using a liquid developer, an electrostatic latent image formed on a photoreceptor, and to an electrophotographic apparatus incorporating the wet-type image forming device.
2. Description of the Related Art
FIG. 1
shows a schematic sectional view of a conventional wet-type image forming device
100
a
. During image formation, within non-discharged areas, which were not exposed to light, of a photoreceptor belt B, a potential difference between the photoreceptor belt B and a development roller
1
generates an electric field having an opposite direction as in discharged areas, which were exposed to light, of the photoreceptor belt B. Accordingly, a reverse development occurs; i.e., toner particles T′ adhere to the development roller
1
. Consequently, problems may arise in the course of subsequent image forming operations such as the image density becoming too high, and a constant gap not being maintained between the photoreceptor belt B and the development roller
1
. Thus, the development roller
1
is cleaned using a potential difference between the development roller
1
and a cleaning roller
3
.
Also, toner particles T′ adhere to a squeeze roller
2
when excess liquid developer T is squeezed off from a developed image formed on the photoreceptor belt B. Consequently, problems may arise in the course of subsequent image forming operations such as the photoreceptor belt B becoming stained as the squeeze roller
2
continues to rotate, and the ability to squeeze off excess liquid developer T being progressively diminished. Thus, the squeeze roller
2
is cleaned using a potential difference between the squeeze roller
2
and the cleaning roller
3
.
Due to the cleaning of the development roller
1
and the cleaning of the squeeze roller
2
, the cleaning roller itself picks up toner particles T′. As the cleaning roller
3
picks up more toner particles T′, the potential differences tend to become insufficient for cleaning between the development roller
1
and the cleaning roller
3
, and between the squeeze roller
2
and the cleaning roller
3
. Thus, the cleaning roller
3
itself is also cleaned.
In the conventional wet-type image forming device
100
a
, the cleaning roller
3
has been cleaned by opposing rotation of the cleaning roller
3
and a brush roller
5
a
in contact therewith, and by a cleaning blade
4
contacting the cleaning roller
3
. That is, the cleaning of the cleaning roller
3
has been performed by mechanical force alone.
The mechanical cleaning, however, has not been sufficient to fully remove the toner particles T′ from the cleaning roller
3
. Therefore, the conventional wet-type image forming device
100
a
has been susceptible to a subsequent problem that the development roller
1
and the squeeze roller
2
are not adequately cleaned.
Furthermore, the conventional wet-type image forming device
100
a
has not been capable of removing toner particles T′ adhering to the brush roller
5
a
. Therefore, the conventional wet-type image forming device
100
a
has also been disadvantageous in that the toner particles T′ accumulate on the brush roller
5
a
, reducing the ability to remove toner particles T′ from the cleaning roller
3
and the cleaning blade
4
.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a wet-type image forming device and an electrophotographic apparatus in which toner particles can be fully removed from the surface of a cleaning roller.
It is another object of the present invention to provide a wet-type image device and an electrophotographic apparatus in which the ability to clean the cleaning roller does not diminish over an extended period of image forming operations.
To this end, the present invention, in one aspect thereof, provides a wet-type image forming device which includes a development roller for developing, using a liquid developer, an electrostatic latent image formed on a photoreceptor, a squeeze roller for squeezing off excess liquid developer from the photoreceptor, a cleaning roller for cleaning the development roller and the squeeze roller, and a brush roller and a cleaning blade for cleaning the cleaning roller, and in which a voltage is applied to the brush roller.
The present invention in another aspect thereof, provides an electrophotographic apparatus comprises a wet-type image forming device, wherein the image forming device includes a development roller for developing, using a liquid developer, an electrostatic latent image formed on a photoreceptor, a squeeze roller for squeezing off excess liquid developer from the photoreceptor, a cleaning roller for cleaning the development roller and the squeeze roller and a brush roller and a cleaning blade for cleaning the cleaning roller, wherein a voltage being applied to the brush roller.
The present invention, in still another aspect thereof, provides a wet-type image forming device which includes a development roller for developing, using a liquid developer containing toner particles, an electrostatic latent image formed on a photoreceptor, a squeeze roller for squeezing off excess liquid developer from the photoreceptor, a cleaning roller for cleaning the development roller and the squeeze roller, a brush roller and a cleaning blade for cleaning the cleaning roller, and a scraping mechanism for scraping toner particles from the brush roller.
The present invention in still another aspect thereof, provides a wet-type image forming device which includes a development roller for developing, using a liquid developer containing toner particles, an electrostatic latent image formed on a photoreceptor, a squeeze roller for squeezing excess liquid developer from the photoreceptor, a cleaning roller for cleaning the development roller and the squeeze roller, a brush roller and a cleaning blade for cleaning the cleaning roller, and a reservoir for storing the liquid developer so that the brush roller is immersed therein during image formation, and in which the reservoir has a protrusion for scraping toner particles from the brush roller.


REFERENCES:
patent: 3884572 (1975-05-01), Bacon et al.
patent: 4482244 (1984-11-01), Yamazaki et al.
patent: 5530537 (1996-06-01), Thayer
patent: 5978630 (1999-11-01), Chang et al.

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