Information
-
Patent Grant
-
6411794
-
Patent Number
6,411,794
-
Date Filed
Thursday, June 15, 200024 years ago
-
Date Issued
Tuesday, June 25, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Fitzpatrick, Cella, Harper & Scinto
-
CPC
-
US Classifications
Field of Search
US
- 399 90
- 399 315
- 399 311
- 399 170
- 399 89
- 361 225
- 361 229
- 361 235
- 250 324
- 250 325
- 250 326
-
International Classifications
-
Abstract
A discharge device has a discharge wire for discharge in response to a voltage, a supporting block for supporting the discharge wire, an electric contact receiving an AC voltage, and a resistor element placed between the discharge wire and the electric contact. The discharge device serves particularly as a separation charger of an image forming apparatus.
Description
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.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a plan view showing a fixing/conveying unit of an image forming apparatus according to a first embodiment of the present invention;
FIG. 2
is a cross-sectional view showing the fixing/conveying unit of the image forming apparatus according to the first embodiment of this invention;
FIG. 3
is an enlarged cross-sectional view showing a high-voltage contact section of the image forming apparatus according to the first embodiment of this invention;
FIG. 4
is an enlarged cross-sectional view showing a high-voltage contact section of an image forming apparatus according to a second embodiment of this invention;
FIG. 5
is a cross-sectional view showing an image forming apparatus; and
FIG. 6
is an enlarged cross-sectional view showing a high-voltage contact section of the image forming apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will be described hereinbelow with reference to the accompanying drawings.
(First Embodiment)
FIG. 1
is a plan view showing a fixing/conveying unit of an image forming apparatus according to a first embodiment of the present invention,
FIG. 2
is a cross-sectional view of the fixing/conveying unit of
FIG. 1
, and
FIG. 3
is an enlarged cross-sectional view showing a high-voltage contact section thereof.
In the image forming apparatus according to this embodiment, a photosensitive drum
1
carries a toner image developed by a developing device (not shown) and, subsequently, the toner image carried on the photosensitive drum
1
is transferred to a transfer material by an operation of a transfer electrifying device
3
. Furthermore, a pair of register rollers
2
convey the transfer material to the toner image on the photosensitive drum
1
, and the transfer electrifying device
3
transfers the toner image on the photosensitive drum
1
onto that transfer material.
The transfer material having thereon the toner image is separated from the photosensitive drum
1
by means of a separation rectifying device
4
and is then conveyed to a pair of fixing rollers
6
through a conveying belt
5
. The fixing roller r pair
6
fix the toner image on the transfer material, following which the transfer material is ejected to the external through the use of a pair of ejecting rollers
7
.
In this composition, the register roller pair
2
, the transfer electrifying device
3
, the separation electrifying device
4
, the conveying belt
5
, the fixing roller pair
6
and the ejecting roller pair
7
are all fixed on a unit base plate
8
, and are constructed as a fixing/conveying unit
9
to be attachable/detachable simultaneously to/from the main body of the image forming apparatus. The transfer electrifying device
3
and the separation electrifying device
4
of this fixing/conveying unit
9
are equipped with high-voltage contact sections
12
a
and
12
b
, respectively (see FIG.
1
). When the fixing/conveying unit
9
is mounted on the image forming apparatus main body, the high-voltage contact sections
12
a
and
12
b
are brought into contact with a main body contact section
13
so that the transfer electrifying device
3
and the separation electrifying device
4
receive a power supply.
In this embodiment, since radiation noise develops in the separation electrifying device
4
for supplying a high AC voltage, the high-voltage contact section for the separation electrifying device
4
in the image forming apparatus are constructed as shown in FIG.
3
.
As
FIG. 3
shows, the high-voltage contact section for the separation electrifying device
4
in the image forming apparatus is made up of a separation electrifying device contact portion
21
, a separation electrifying device block
22
, a resistor
23
, a connecting portion
24
, a spring latching plate
25
, a main body contact
31
, a main body contact block
32
, a base plate contact
33
and a main body frame
40
.
The high-voltage contact section
12
b of the separation electrifying device
4
is constructed with the separation electrifying device contact portion
21
, the resistor
23
and the connecting portion
24
embedded in the separation electrifying device block
22
, and the separation electrifying device contact portion
21
, the resistor
23
and the connecting portion
24
are connected electrically to each other. Additionally, the spring latching plate
25
is attached through a screw
27
to the connecting portion
24
. Incidentally, it is also appropriate that the connecting portion
24
and the spring latching plate
25
are constructed as an integrated unit.
In addition, an electrifying wire (not shown) is attached through a spring
26
to the spring latching plate
25
to establish an electrical connection.
On the other hand, in the main body high-voltage contact section
13
of the image forming apparatus, the main body contact
31
made from a metallic elastic material and the base plate contact
33
are attached to the main body contact block
32
, with the main body contact
31
and the base plate contact
33
connected electrically to each other. The base plate contact
33
is also connected to a main body high-voltage base plate (not shown), while the main body contact block
32
is fit into an opening portion
40
a
, made in a rear surface of the main body frame
40
, to be set thereat.
The separation electrifying device contact portion
21
is inserted into the opening portion
40
a
made in the rear surface of the main body frame
40
and is brought into contact with the main body contact
31
, situated on the rear surface of the main body frame
40
, to establish electrical connection between separation electrifying device contact portion
21
and main body contact
31
. A high AC voltage generated from a main body pressing base plate (not shown) is supplied to the base plate contact
33
, the main body contact
31
and the separation electrifying device contact portion
21
in this order so that the electrifying wire (not shown) performs the corona discharge, that is, conducts the transfer material separating operation. The separation electrifying device contact portion
21
is formed into a conical configuration. The reason for a conical configuration is that when the fixing/conveying unit
9
is mounted in the image forming apparatus in a state where the transfer material is left in error after a jam handling operation or the like, there is the possibility of a fire if the transfer material is put between the separation electrifying device contact portion
21
and the main body contact
31
. Accordingly, to prevent this, the separation electrifying device contact portion
21
is made pointed so as to break through the transfer material and, further, to come into contact with the main body contact
31
for securing the electrical connection.
While the separation electrifying device
4
conducts the separating operation, a radiation noise occurs in the high-voltage contact section and, if the right-hand area of the main body frame
40
is designed to be exterior of the apparatus, then this creates an apparatus radiation noise problem. However, in this embodiment, the resistor
23
is placed in the left-hand area (the front side of the opening portion
40
a
of the main body frame
40
) with respect to the vicinity of the main body frame
40
and the power load such as the corona discharge is disposed downstream, which reduces the radiation noise occurring in the high-voltage contact section so that the radiation noise occurring on the right side of the main body frame
40
is reduced. That reduction effect was as much as 10 dB or more, and it was confirmed that this arrangement functions sufficiently as a countermeasure against the radiation noise.
(Second Embodiment)
Referring to
FIG. 4
, a description will be given hereinbelow of a second embodiment of this invention.
FIG. 4
is an enlarged cross-sectional view showing a high-voltage contact section for a separation electrifying device
4
in an image forming apparatus according to this embodiment.
In this embodiment, the high-voltage contact section
12
b
for the separation electrifying device
4
in the image forming apparatus is composed of a separation electrifying device contact portion
21
′, a separation electrifying device block
22
′, a resistor
23
, a connecting portion
24
′, a spring latching plate
25
, a main body contact
31
′, a main body contact block
32
′, a base plate contact
33
′ and a main body frame
40
.
In the high-voltage contact section
12
b
for the separation electrifying device
4
, the separation electrifying device contact portion
21
′ and the spring latching plate
25
are fit through the connecting portion
24
′ to the separation electrifying device block
22
′. The connecting portion
24
′ is constructed such that metallic ping
24
′
a
and
24
′
b
are connected to the resistor
23
and a mold
24
′
c
is put around them to form a cylindrically embedded configuration.
The separation electrifying device contact portion
21
′, the resistor
23
and the spring latching plate
25
are connected electrically to each other, and an electrifying wire (not shown) is attached through a spring
26
to the spring latching plate
25
to establish electrical connection.
On the other hand, in the main body high-voltage contact section
13
of the image forming apparatus, the main body contact
31
′ made from a metallic elastic material is attached to the base plate contact
33
′, and the base plate contact
33
′ is attached to the main body contact block
32
′. The main body contact
31
′ and the base plate contact
33
′ are connected electrically to each other, while the base plate contact
33
′ is connected to a main body high-voltage base plate (not shown). Additionally, the main body contact block
32
′ is fitted in an opening portion
40
a
, made in a rear surface of the main body frame
40
, to be set thereat.
The separation electrifying device contact portion
21
′ is inserted into the opening portion
40
a
made in the rear surface of the main body frame
40
and is brought into contact with the main body contact
31
′ situated on the rear surface of the main body frame
40
to establish an electrical connection therebetween. A high AC voltage generated from a main body pressing base plate (not shown) is supplied to the base plate contact
33
′, the main body contact
31
′ and the separation electrifying device contact portion
21
′ so that the electrifying wire (not shown) performs the corona discharge to conduct the transfer material separating operation.
This embodiment is characterized in that the connecting portion
24
′ is made to be attachable/detachable with respect to the separation electrifying device block
32
′. This is because, taking into consideration a radiation noise countermeasure in the image forming apparatus, easy changing of the resistor
23
allows a wider range of applications. The frequency of the radiation noise can vary according to the using condition of the image forming apparatus. At this time, if the resistor
23
is embedded in the separation electrifying device block
32
′ as well an the above-described first embodiment, the image forming apparatus requires a new mold for the separation electrifying device block
32
at every specification.
Accordingly, in this embodiment, since the connecting portion
24
′ is detachable, when a need for changing of the type of the resistor
23
arises, the alteration can be confined to a minimum. Thus, this construction can flexibly cope with various specifications. Also in this embodiment, it was confirmed that sufficient effects are attainable for the reduction of radiation noise.
It should be understood that the foregoing relates to only preferred embodiments of the present invention, and that it is intended to cover all changes and modifications of the embodiments of the invention herein used for the purpose of the disclosure, which do not constitute departures from the spirit and scope of the invention. For example, although the above description of the embodiments have been made in conjunction with a separation electrifying device of an image forming apparatus, this invention is also applicable to other discharge devices receiving supply of an AC voltage.
Claims
- 1. A discharge device comprising:a discharging wire; a supporter member for supporting said discharging wire; an electrifying device contact portion; and a resistor element placed between said supporter member and said electrifying device contact portion.
- 2. A discharge device according to claim 1, wherein an AC voltage is applied to said electrifying device contact portion.
- 3. A discharge device according to claim 1, wherein said electrifying device contact portion has a conical shape and is adapted for contact with a conductive elastic member.
- 4. A discharge device according to claim 1, wherein said resistor element is attachable to and detachable from said supporter member.
- 5. An image forming apparatus comprising:an AC base plate; a main body contact connected to said AC base plate; a frame installed on a rear side of a main body of said image forming apparatus; and an attachable/detachable discharging means, comprising: a discharging member; a supporter member for supporting said discharging member; an electrifying device contact portion in contact with said main body contact; and a resistor element placed between said discharging member and said electrifying device contact portion, wherein said main body contact is disposed exterior to said frame.
- 6. An image forming apparatus according to claim 5, wherein said frame has an opening portion for enabling contact of said electrifying device contact portion with said main body contact with said discharging means is mounted.
- 7. An image forming apparatus according to claim 5, wherein said resistor element is disposed interior of said frame.
- 8. An image forming apparatus according to claim 5, further comprising a separation rectifying device, wherein an AC voltage is applied to the separation rectifying device through a discharge wire.
- 9. An image forming apparatus according to claim 5, wherein said main body contact is a conductive elastic member.
- 10. An image forming apparatus according to claim 5, wherein said resistor element is attachable to and detachable from said supporter member.
- 11. An image forming apparatus according to claim 5, wherein an image forming unit is contained within the frame and said image forming unit comprises an image carrier for carrying a toner image and transfer means for transferring said toner image on said image carrier to a transfer material, and wherein said attachable/detachable discharging means conducts electrification elimination of said transfer material after the transferring.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-171045 |
Jun 1999 |
JP |
|
US Referenced Citations (4)
Foreign Referenced Citations (1)
Number |
Date |
Country |
59-102258 |
Jun 1984 |
JP |