Electrophotography – Image formation – Transfer
Reexamination Certificate
2000-06-15
2002-06-25
Chen, Sophia S. (Department: 2852)
Electrophotography
Image formation
Transfer
C250S325000, C399S090000, C399S170000, C399S311000
Reexamination Certificate
active
06411794
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a discharge device and image forming apparatuses, such as copying machines and printers, using a discharge device.
2. Description of the Related Art
FIG. 5
is a cross-sectional view of a copying machine of the electrophotographic type.
As
FIG. 5
shows, an electrostatic image is formed on the surface of a photosensitive drum
104
through the use of an optical unit
103
, an electrifying device
203
and other components and, subsequently, a toner serving as a developer is attached to the electrostatic image by means of a developing device
201
so that the electrostatic image develops into a visible image. Additionally, this visible image is transferred through a transferring device
111
onto a transfer material conveyed by feeding means
105
to
110
and the transfer material with the visible image on it is separated from the photosensitive drum
104
by a separating device
112
and subsequently conveyed by a conveying means
113
to a fixing device
114
where it is heated and pressurized to fix the visible image. The transfer material on which the visible image has been fixed is ejected outside of the copying machine through an ejecting device
116
.
Meanwhile, if a paper jam occurs during an image forming operation, the removal of the jammed paper becomes necessary. In addition, a need for periodical apparatus-interior maintenance exists. Therefore, for easy jam elimination and maintenance, there has been proposed a construction in which a section indicated by a broken line in
FIG. 5
is made as a single fixing/conveying unit
300
and this fixing/conveying unit
300
is drawable toward the front side of the image forming apparatus along a guide rail (not shown).
In this construction, the fixing/conveying unit
300
includes the transferring device
111
and the separating device
112
, which each require a high-voltage contact for its power supply. For the unit configuration, the high-voltage contact is disposed in the vicinity of either the transferring device
111
or the separating device
112
and at a position where the connection with the main body is facilitated. Taking this into consideration, the high-voltage contact is positioned on the rear surface of the transferring device
111
and the separating device
112
, that is, on the rear surface of the fixing/conveying unit
300
.
Furthermore, an AC voltage is to be applied to the separating device
112
. The electrifying device, thus designed to use an AC voltage, tends to generate radiation noise.
FIG. 6
is an enlarged cross-sectional view showing a high-voltage contact section for the separating device
112
in the image forming apparatus of FIG.
5
.
As
FIG. 6
shows, the high-voltage contact section for the separating device
112
in the image forming apparatus is composed of a separating device contact portion
51
, a separating device block
52
, a spring latching plate
55
, a main body contact
61
, a main body contact block
62
, a base plate contact
61
and a main body frame
70
.
The high-voltage contact section for the separating device
112
is constructed in a manner that the separating device contact portion
51
is inserted into a cylindrical portion
52
a
of the separating device block
52
and secured to a spring latch
55
. Additionally, an electrifying wire (not shown) is attached through a spring
56
to the spring latch
55
to establish the electrical connection.
On the other hand, in the contact section on the image forming apparatus main body side, the main body contact
61
and the base plate contact
63
are attached to the main body contact block
62
, with them being connected electrically to each other. Additionally, the base plate contact
63
is connected to a main body high-voltage base plate (not shown), while the main body contact block
62
is attached to the main body frame
70
.
The separating device contact portion
51
is brought into contact with the main body contact
61
, the latter made with an elastic material, thereby establishing electrical connection therebetween. A high AC voltage generated from a main body high-voltage base plate (not shown) is supplied to the base plate contact
63
, the main body contact
61
and the separating device contact portion
51
so that the electrifying wire (not shown) produces corona discharge, thereby accomplishing separation of a transfer material.
While the separating device
112
conducts the separating operation, a radiation noise may occur at the high-voltage contact section.
If a right-hand area of the main body frame
70
is exterior to the apparatus, the radiation noise tends to leak toward the exterior of the apparatus. For this reason, a shielding mechanism is required to prevent the leakage of the radiation noise.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an image forming apparatus capable of reducing noises to be radiated to the external.
Another object of this invention is to provide a discharge device capable of reducing radiation noise at a high-voltage contact section.
In accordance with these objects, there is provided a discharge device comprising a discharging unit, a supporting member for supporting the discharging unit, and an electrifying device contact portion. A resistor element is placed between the discharging unit and the electrifying device contact portion.
In accordance with another aspect of the invention there is provided an image forming apparatus with an image forming unit having a high-voltage component. An AC base plate communicates power to the high-voltage component of the image forming unit thru a main body contact and an attachable/detachable high-voltage contact section. The high-voltage contact section includes a discharging unit, a supporting member for supporting the discharging unit, an electrifying device contact portion in contact with the main body contact and a resistor element placed between the discharging unit and the electrifying device contact portion.
Other objects of the present invention will become more readily apparent from the following description.
REFERENCES:
patent: 2863063 (1958-12-01), Schulze
patent: 4307431 (1981-12-01), Sone et al.
patent: 4466729 (1984-08-01), Iwata
patent: 5381216 (1995-01-01), Osaka et al.
patent: 59-102258 (1984-06-01), None
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