Electrophotography – Cleaning of imaging surface – Having handling of removed material
Reexamination Certificate
2002-12-12
2004-11-02
Lee, Susan (Department: 2852)
Electrophotography
Cleaning of imaging surface
Having handling of removed material
C399S113000, C399S119000, C399S120000
Reexamination Certificate
active
06813469
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a toner cartridge assembly and a printing apparatus.
2. Description of the Related Art
A conventional printing apparatus using an electrophotographic method such as a laser printer, a photocopying machine, or a facsimile machine develops a desired image by developing an electrostatic latent image with a developing agent, after forming the electrostatic latent image by projecting a laser beam on a photosensitive medium such as a photosensitive drum. The image developed on the photosensitive medium is transferred to a printing paper passing through to a transfer nip between the photosensitive medium and a transfer roller, and is settled on the printing paper at a settlement unit.
The printing apparatus has a developing cartridge to form the image. Referring to
FIG. 1
, the conventional developing cartridge has a developing unit and a toner supplying unit including a cartridge body
10
. The cartridge body
10
has a charging roller
12
, a developing roller
13
, and a cleaning blade
14
, all surrounding a photosensitive drum
11
.
Moreover, inside of the cartridge body
10
, there is a used toner chamber
10
a
at one side of the photosensitive drum
11
and a new toner chamber
10
b
at another side of the photosensitive drum
11
.
According to the above structure, the photosensitive drum
11
is charged by the transfer roller
12
, and an electrostatic latent image is formed on one side thereof by a light charging roller
12
, and an electrostatic latent image is formed on one side thereof by a light projected from a laser projection unit (not shown). In addition, a visible image is formed at the electrostatic latent image area as toner supplied from the new toner chamber
10
b
is transferred by the developing roller
13
. The formed visible image is copied to the paper P passing through between the photosensitive drum
11
and a developing roller
20
.
In the meantime, in the developing cartridge having the above structure, the elements inside of the cartridge body
10
are manufactured together, and when the toner is used up, the entire cartridge is exchanged. Therefore, the elements cannot be individually exchanged. Accordingly, a contact status (hereinbelow, referred to as a developing nip) between the photosensitive drum
11
and the developing roller
13
is compulsorily regulated.
However, according to the above structure, as the photosensitive drum
11
and the developing roller
13
are installed to be fixed at the cartridge body
10
, the developing nip between the photosensitive drum
11
and the developing roller
13
is irregular, thus there are problems caused by the developing nip.
The irregular developing nip is caused by run out of the elements of the photosensitive drum
11
and the developing roller
13
. In other words, the run out of the photosensitive drum
11
cannot be reduced within 0.05 mm, and the run out of the developing roller
13
reaches up to 0.1 mm. When two elements are united, the developing nip in a lengthwise direction of the photosensitive drum
11
is 0-0.15 mm.
When the developing nip in the developing cartridge of a contact developing method is zero, the toner on the developing roller
13
can be theoretically developed on the photosensitive drum
11
. Yet, in practice, the toner can be developed when the overlapping volume of a distance between axes of the developing roller
13
and the photosensitive drum
11
is at least 0.05 mm.
Therefore, the developing nip is within the range of 0.05 mm to 0.2 mm as the overlapping volume of the distance between the axes, the developing roller
13
and the photosensitive drum
11
have a contact area having 0.05 mm of the overlapping volume and another contact area having 0.2 mm of the overlapping volume. Furthermore, there is a large difference in the mechanical power that the toner receives at a contact area having different overlapping volumes from each other.
If the developing nip is irregular in the lengthwise direction of the photosensitive drum
11
, the toner cannot stably settle on the photosensitive drum
11
when the toner is transferred from the developing roller
13
to the photosensitive drum
11
, and the toner is removed or recollected to the developing roller
13
. Therefore, there is a problem in the image, specifically, the density of the image is not uniform, or the image is distorted.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to overcome the above-mentioned problems of the prior art.
It is another object of the present invention to provide a toner cartridge assembly and a printing apparatus having an improved structure to maintain the developing nip as the toner cartridge assembly is settled by being separated from a photosensitive drum cartridge.
Additional objects and advantages 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.
The foregoing and other objects of the present invention are achieved by providing a toner cartridge assembly installed to correspond to a photosensitive drum cartridge disposed at a printing apparatus body, the toner cartridge assembly to develop toner on the photosensitive drum and collect used toner on the photosensitive drum, the toner cartridge assembly including a toner cartridge to correspond to the photosensitive drum cartridge at the body, having a developing roller to develop the toner on the photosensitive drum, a developing nip being formed between the developing roller and the photosensitive drum; and a used toner chamber movably connected to a side of the toner cartridge, the used toner chamber to store the used toner collected from the photosensitive drum cartridge, wherein the used toner chamber is fixed to the printing apparatus body, and the toner cartridge adjusts the developing nip by being connected with the used toner chamber such that the toner cartridge reciprocates and rotates in a direction of the photosensitive drum.
According to an aspect of the present invention, the toner cartridge reciprocates for a predetermined distance and rotates in relation to the used toner chamber.
According to another aspect of the present invention, the toner cartridge assembly further includes a first screw; a second screw; a first boss connected with the first screw to guide the reciprocation and the rotation of the toner cartridge; a second boss connected with the second screw to guide the reciprocation of the toner cartridge and to regulate a rotation angle of the toner cartridge, the first and second bosses being disposed at the side of the toner cartridge; a longitudinal hole formed in the used toner chamber to guide the reciprocation of the toner cartridge by being connected with the first screw; and a reaming hole formed in the used toner chamber to limit the rotation angle of the toner cartridge by limiting a range of movement of the second screw.
The toner cartridge assembly may further include a flange portion having a greater diameter than the longitudinal hole and the reaming hole, formed at each head portion of the first and second screws.
The toner cartridge assembly may further include a position deciding unit relatively coupled with a predetermined position of the body in order to fix a settlement position when being installed at the body.
According to yet another aspect of the present invention, the position deciding unit includes a pair of position deciding holes disposed at an upper part of the used toner chamber in order to be relatively connected with position deciding pins disposed at a predetermined area of the body.
The toner cartridge assembly may further include portions, disposed at an outer side of the toner cartridge, stepped in a direction in which the toner cartridge is installed at the body. The stepped portions guide the toner cartridge to the photosensitive drum cartridge when being installed at the body.
The foregoing and other objects of the present inventio
Samsung Electronics Co,. Ltd.
Staas & Halsey , LLP
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