Electrophotography – Control of electrophotography process – Control of fixing
Reexamination Certificate
2000-07-28
2002-11-26
Royer, William J. (Department: 2852)
Electrophotography
Control of electrophotography process
Control of fixing
C399S068000, C399S069000, C399S325000
Reexamination Certificate
active
06487381
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fixing apparatus applied to image forming apparatuses such as a copying machine and a printer, particularly to an apparatus for applying a fixing member with a releasing agent.
2. Related Background Art
FIG. 10
shows a fixing apparatus as a background art of the present invention.
As shown in detail in
FIG. 10
, the fixing apparatus is constituted of a fixing roller
510
as a fixing rotating member which is rotatably disposed, a pressurizing roller
520
as a pressurizing rotating member which is pressed in contact with the fixing roller
510
and rotates, a releasing agent applying apparatus
530
as releasing agent applying means, cleaning apparatuses
540
,
550
, and the like. Additionally, heaters
560
,
570
such as halogen lamps are disposed inside the fixing roller
510
and pressurizing roller
520
, respectively. Moreover, thermistors
580
,
590
are disposed to abut on the fixing roller
510
and pressurizing roller
520
, respectively, and surface temperatures of the fixing roller
510
and pressurizing roller
520
are adjusted by controlling voltages to the heaters
560
,
570
via a temperature adjustment circuit.
The releasing agent applying apparatus
530
is constituted of: a releasing agent reservoir
530
a
for containing releasing agents such as silicone oil; pumping rollers
530
b
,
530
c
for pumping the releasing agent from the releasing agent reservoir
530
a
; an applying roller
530
d
for applying the pumped releasing agent to the fixing roller
510
; a regulating blade
530
e
, formed of elastic materials such as fluorine rubber, for regulating a releasing agent amount on the applying roller
530
d
to provide a constant amount; and the like. Particularly to realize uniform applying of the fixing roller
510
with the releasing agent, the releasing agent applying apparatus
530
is disposed on the downstream side of the rotation direction of the fixing roller
510
with respect to the thermistor
580
.
Therefore, when a recording sheet P is conveyed, the fixing roller
510
and pressurizing roller
520
rotate, and the surface of the fixing roller
510
is applied with silicone oil as the releasing agent. When the recording sheet P passes between the fixing roller
510
and the pressurizing roller
520
, the recording sheet is pressurized and heated with substantially constant pressure and temperature from both front and back surfaces, an unfixed toner image is fixed and an image is formed on the recording sheet P. Moreover, the recording sheet P with the image fixed thereto is separated from the pressurizing roller
520
by a lower separating pawl
680
and discharged to the outside.
However, this apparatus has the following problem.
Namely, the general thermal fixing apparatus in a copying machine or the like is on standby for a predetermined time after power is turned on until the fixing roller reaches a predetermined temperature, and a copy enable state is obtained after the fixing roller reaches the predetermined temperature. Fixing properties differ immediately after the copy enable state is obtained (hereinafter referred to as “state of first run in the morning”), and when the apparatus is left on standby in the copy enable state and a predetermined time elapses (hereinafter referred to as “left state”). This is because not only the surface temperature of the fixing roller but also the temperature of the entire fixing apparatus and particularly the temperature of the releasing agent applied to the fixing roller surface differ with the state of first run in the morning and the left state. Namely, in the left state, since fixing roller heat is conducted to the releasing agent via the applying roller and pumping roller, the releasing agent gains a high temperature. In this state, even when the releasing agent is applied to the fixing roller, the fixing roller indicates a little temperature drop.
Additionally, since the releasing agent present between the fixing roller and toner also has a high temperature, the fixing property is enhanced.
On the other hand, in the state of first run in the morning, the temperature of the releasing agent is low. When the low-temperature releasing agent is applied to the fixing roller surface, the temperature of the fixing roller rapidly lowers. Additionally, since the low-temperature releasing agent exists between the fixing roller and toner surface, the fixing property is deteriorated. This is further remarkable in a low temperature environment.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a fixing apparatus which performs satisfactory fixing irrespective of temperature of a releasing agent.
Another object of the present invention is to provide a fixing apparatus comprising: a fixing member for fixing an unfixed image onto a recording material; releasing agent applying means for applying a releasing agent to the fixing member; temperature detecting means for detecting temperature of the releasing agent; and control means for controlling a fixing condition in accordance with a detected temperature from the temperature detecting means.
Further objects of the present invention will be apparent in the following description.
REFERENCES:
patent: 4087676 (1978-05-01), Fukase
patent: 4193681 (1980-03-01), Tanigawa et al.
patent: 4563073 (1986-01-01), Reynolds
patent: 5463457 (1995-10-01), Takeuchi et al.
patent: 5563695 (1996-10-01), Sakurai et al.
patent: 5608508 (1997-03-01), Kumagai et al.
patent: 5729818 (1998-03-01), Ishizuka et al.
patent: 5903799 (1999-05-01), Saito et al.
patent: 5966578 (1999-10-01), Soutome et al.
patent: 6088546 (2000-07-01), Inoue et al.
patent: 0 821 289 (1998-01-01), None
patent: 54-8539 (1979-01-01), None
Fujita Takashi
Inoue Keisuke
Ishizuka Jiro
Shimada Shozo
LandOfFree
Fixing apparatus in which heating conditions can be changed... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fixing apparatus in which heating conditions can be changed..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fixing apparatus in which heating conditions can be changed... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2939778