Electrophotography – Internal machine environment – Particle or contaminant control
Reexamination Certificate
2000-07-31
2002-01-01
Grainger, Quana M. (Department: 2852)
Electrophotography
Internal machine environment
Particle or contaminant control
C399S105000
Reexamination Certificate
active
06336015
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a developing apparatus preferably for use in an image forming apparatus such as an electrophotographic copier, an electrophotographic printer, a facsimile apparatus or a word processor, or a process cartridge.
2. Related Background Art
In an electrophotographic copier or the like, a latent image formed on an electrophotographic photosensitive drum which is an image bearing member is developed into a visible image with a toner, and a developing apparatus for supplying the toner to the photosensitive drum is comprised of a developing frame containing the toner therein, and a developing roller which is a developer carrying member and a developing blade which is a developer regulating member mounted on the developing frame. The toner is fine powder, and as shown in
FIG. 8
of the accompanying drawings, in order to prevent the toner from leaking through the gaps between the developing frame
50
and the developing roller
51
, elastic members
52
such as felt or rubber for sealing the gaps between the developing frame
50
and the developing roller
51
in the lengthwisely opposite end portions of the developing roller
51
have been attached.
If the toner used is a magnetic toner having magnetism, instead of the elastic members
52
, as shown in
FIG. 9
of the accompanying drawings, magnetic seal members
53
each having an arcuate portion
53
a
opposed to the developing roller and formed of a magnetic material are mounted so as to provide a minute interval with respect to the developing roller, and the magnetic toner is attracted by a magnetic force to thereby prevent the leakage of the toner. These magnetic seal members
53
do not abut against the developing roller
51
and therefore, there is the advantage that it becomes possible to make the rotational torque of the developing roller
51
small and the assemblage of the magnetic seal members to the developing frame
50
becomes easy.
Also, in the developing apparatus, a developing blade for regulating the layer thickness of the toner borne on the developing roller
51
is mounted on the developing frame
50
, and in order that the toner may not leak from the gap between this developing blade and the developing frame
50
, as shown in
FIGS. 9 and 10
of the accompanying drawings, a lower blade seal member
54
is mounted between the developing frame
50
and the developing blade (not shown). In a construction in which the gaps are sealed by the magnetic seal members
53
, the lengthwise end portions of this lower blade seal member
54
and the magnetic seal members
53
are mounted with minute spacings h and i therebetween, and blade end portion seals
55
are mounted to prevent the toner from leaking through the minute gaps h and i when the developing blade is mounted.
The magnetic seal members
53
are such that only the arcuate portions
53
a
thereof opposed to the developing roller
51
are formed of a magnetic material and the straight portions
53
b
thereof opposed to the blade end portion seal members
55
and the lengthwise end portions of the lower blade seal member
54
have no magnetism. Therefore, to reliably prevent the leakage of the toner, it is necessary to enhance the dimensional accuracy of the minute spacings h and i.
The magnetic seal members
53
, however, are rigid members and the developing frame
50
on which they are mounted is also a rigid member and therefore, mounting backlash is liable to occur. Therefore, it has been necessary to effect the mounting of the seal members
53
especially carefully.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a developing apparatus in which the leakage of a developer is prevented without the mounting accuracy of magnetic seal members being enhanced.
It is another object of the present invention to
Further, in order to prevent the toner from leaking from between the developing blade
9
d
which is a developer regulating member and the developing frame
12
when the developing blade
9
d
is mounted, as shown in
FIGS. 4 and 5
, a lower blade seal member
16
of urethane or like material is stuck on the developing blade mounting position of the developing frame
12
with substantially the same length as the length of the developing blade
9
d,
and the developing blade
9
d
is mounted thereon. The magnetic seal members
14
are mounted so that the straight portions
14
b
thereof may be opposed with minute gaps h and i from the lengthwise end portions of the lower blade seal member
16
. Also, blade end portion seal members
17
are mounted to prevent the toner from leaking from the minute spacings h and i when the developing blade
9
d
is mounted.
The straight portions
14
b
of the magnetic seal members
14
are mounted so as to be opposed to the lengthwise end portions of the lower blade seal member
16
and the blade end portion seal members
17
with the minute gaps h and i. The magnetic seal members
14
have magnetic portions formed not only on the arcuate portions
14
a
but also on the straight portions
14
b
and therefore, a magnetic force acts also on the gaps h and i. Therefore, the magnetic toner in the gaps h and i is attracted by the aforementioned magnetic force and it never happens that the toner leaks from the gaps h provide a developing apparatus in which the developer leakage preventing effect of magnetic seal members is extended to the vicinity of a regulating member.
Further objects and features of the present invention will become more fully apparent from the following detailed description when read with reference to the accompanying drawings.
REFERENCES:
patent: 5068691 (1991-11-01), Nishio et al.
patent: 5073797 (1991-12-01), Ono et al.
patent: 6021291 (2000-02-01), Karakama et al.
patent: 6032012 (2000-02-01), Hirono et al.
patent: 6038414 (2000-03-01), Inami et al.
patent: 6044237 (2000-03-01), Numagami et al.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grainger Quana M.
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