Electric heating – Heating devices – Combined with diverse-type art device
Reexamination Certificate
1997-09-09
2001-11-27
Heinrich, Samuel M. (Department: 1725)
Electric heating
Heating devices
Combined with diverse-type art device
C219S539000, C219S121690
Reexamination Certificate
active
06323460
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a fixing device usable with an image forming apparatus such as a copying machine and a printer, more particularly to a heater usable for a fixing device thereof.
Recently, a film heating type heating device has been proposed and has been put into practice.
An example of such a heating device is shown in FIG.
9
(
a
).
In FIG.
9
(
a
), designated by
8
is a film;
9
is a pressing roller;
10
is a heating member; and
11
is a supporting member for supporting the heating member. In this heating device, a recording material P carrying an unfixed toner image T is introduced into a nip formed between the heating member
10
and the pressing roller
9
with the film
8
therebetween, and the unfixed toner image is fixed on the recording material by the heat from the heating member
10
through the film
8
.
The film heating type heating device is advantageous in that use can be made with a heating member or thin film having low heat capacities which exhibit a quick temperature rise, and therefore, the temperature of the heating member can be quickly increased, thus permitting electric power saving and reduction of the wait time.
FIG.
9
(
b
), and FIG.
9
(
a
) are top plan views of such a heating member.
In FIG.
9
(
b
), designated by
10
is a heating member, which comprises a heater substrate
2
, a heat generating resistor (energization heat generating element) pattern
3
on one side of the heater substrate
2
, a conductive member pattern
4
, an electroconductive pattern
4
a
, two electric energy supply electrode patterns
5
and
6
, and a surface protection layer
7
covering the heat generating resistor pattern
3
and the conductive member pattern
4
, and the like.
The heat generating resistor pattern
3
is formed by coating through screen printing or the like electric resistance material paste (resistance paste) of silver palladium (Ag/Pb), Ta
2
N or the like into a thickness of 10 microns and a width of 1-3 mm, for example, on a ceramic base material in a longitudinal direction, and by sintering it.
The conductive member pattern
4
is formed along a longitudinal surface of the ceramic base material in the form of a stripe extending substantially parallel with the heat generating resistor pattern
3
.
The two electric energy supply electrode patterns
5
,
6
are juxtaposed adjacent one end side of the ceramic base material
2
.
An end of the heat generating resistor pattern
3
is electrically connected by the electroconductive pattern
4
a
and the electric energy supply electrode pattern
5
. An end of the conductive member pattern
4
adjacent said end is electrically connected with the other electric energy supply electrode pattern
6
. The other ends of the heat generating resistor pattern
3
and conductive member pattern
4
are electrically connected with each other.
The conductive member pattern
4
, the conduction pattern
4
a
, and the two electric energy supply electrode patterns
5
,
6
, are formed by pattern coating using screen printing or the like and sintering of electroconductive material paste such as Ag on the surface of the ceramic base material
2
.
The substantially parallel heat generating resistor pattern
3
and conductive member pattern
4
form a forward path and backward path of energization in the direction of the length of the heating member between two electric energy supply electrode patterns
5
,
6
adjacent one longitudinal end of the ceramic base material
2
.
In the case of this example, the two electric energy supply electrode portions
5
,
6
for the heat generating resistor pattern
3
are disposed adjacent one longitudinal end of the heating member substrate (ceramic base material), and therefore, the electric energy supply connector for the heating member
10
may be provided adjacent only one longitudinal end, so that the electric energy supply for wiring is simplified, and the wiring operation is easy.
With this structure, the heat generating resistor pattern
3
constitutes a forward path of energization, and the backward path is constituted by a conductive member pattern
4
having a low resistance and therefore, does not generate heat. In this case, a difference in thermal expansion coefficient occurs at the heating member portion in the forward path side and backward path side so that the heating member is relatively easily broken.
The heating member
10
has a relatively large width of the substrate
2
to permit formation of the conductive member pattern
4
. If, however, the width of the heat generating resistor pattern
3
is increased to increase the fixing property, the width of the substrate
2
has to be increased from the standpoint of withstanding voltage, with the result of deterioration of the productivity.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide a heating member and a fixing device having the same wherein breakage of the heating member due to the strain resulting from a difference in thermal-expansion is effectively prevented.
It is another object of the present invention to provide a heating member and a fixing device wherein the productivity is not lowered even if the fixing property is improved.
According to an aspect of the present invention, there is provided a heater comprising: an elongated base member; first and second resistors extended in a longitudinal direction of said base member; an electric conducting portion, adjacent an end of said base member, for electrically conducting said first resistor and second resistor; and electrodes, provided only adjacent the other end of said base member, for supplying electric energy to said first resistor and second resistor to generate heat by said electrodes.
According to another aspect of the present invention, there is provided an image fixing apparatus comprising: a heater; a film having a surface in slidable contact with said heater and an opposite surface movable together with a recording material, wherein an unfixed image is fixed on the recording material by the heat from said heater; said heater including: an elongated base member; first and second resistors extended in a longitudinal direction of said base member; an electric conducting portion, adjacent an end of said base member, for electrically conducting said first resistor and second resistor; and electrodes, provided only adjacent the other end of said base member, for supplying electric energy to said first resistor and second resistor to generate heat by said electrodes.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following invention taken in conjunction with the accompanying drawings.
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patent: 5306898 (1994-04-01), Yukkawa et al.
patent: 5338919 (1994-08-01), Tagashira et al.
patent: 5376773 (1994-12-01), Masuda et al.
patent: 5444521 (1995-08-01), Tomoyuki et al.
patent: 5464964 (1995-11-01), Okuda et al.
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patent: 0360418 (1990-03-01), None
patent: 0372479 (1990-06-01), None
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patent: 0604977 (1994-07-01), None
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European Search Report EP 95 113536 May 9, 1996.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Heinrich Samuel M.
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