JP3826683B2 - Incandescent lamp for heat source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an incandescent lamp for a heat source, and more particularly to an incandescent lamp for a heat source used for a heating roller of an electrophotographic copying machine or a printer.
[0002]
[Prior art]
Conventionally, an incandescent lamp for a heat source is incorporated as a heat source in a heating roller of an electrophotographic copying machine or a printer. Japanese Patent Application Laid-Open No. 10-106510 discloses an example of such an incandescent lamp for a heat source.
[0003]
FIG. 1 is a front view showing an example of a heating roller used in a fixing device such as an electrophotographic copying machine or a printer according to the prior art.
[0004]
As shown in the figure, the heating roller 10 has a sleep-like roller, in which an incandescent lamp 20 for heat source is arranged, and a rotation driving gear 11 is fixed to one end of the heating roller 10 and the other end. Is configured to be rotatable by being supported by the rotation support member 12.
[0005]
Usually, the heating roller 10 is required to have a uniform surface temperature in the longitudinal direction, but heat is taken away by the rotation drive gear 11 and the rotation support member 12 at both ends of the heating roller 10, Since the heat radiation action is larger than that in the central region, if the heating roller 10 is simply heated uniformly in the longitudinal direction, the surface temperature of the heating roller 10 is greatly reduced at both ends. In order to avoid such a situation, in order to make the surface temperature of the heating roller 10 uniform over the entire length in the longitudinal direction, the degree of heating at both ends of the heating roller 10 is made higher than the other central region. Yes.
[0006]
FIG. 2 is a front view showing the configuration of an incandescent lamp for a heat source for making the amount of heat generated at both ends of the heating roller 10 larger than the central region.
[0007]
As shown in the figure, in the incandescent lamp 20 for heat source, a plurality of light emitting portions 22 and 23 and a non-light emitting portion 24 are alternately arranged in a glass tube-type bulb 21 along the tube axis direction. The filament F is supported by a filament supporter (not shown), and both ends of the filament F extend from a metal foil 25 made of molybdenum foil or the like embedded in pinch seal portions at both ends of the valve 21, and the metal foil 25. It is connected to the external lead 26. Furthermore, as shown in the figure, the filament F has two light emitting portions 22 and 22 corresponding to both end portions of the heating roller 10, and a plurality of central region light emitting portions 23 corresponding to the central region, In order to obtain a larger amount of heat generation at the end light emitting units 22, 22, the heating coil length is made larger than each central region light emitting unit 23.
[0008]
On the other hand, a heating roller used in an electrophotographic copying machine, a printer, etc., after the main switch of the apparatus is turned on, the surface temperature of the heating roller rises to a uniform and usable temperature range within a short period of time. Then, the recording paper to which the toner is attached is conveyed between the pressure roller that rotates together, and the toner is fixed to the recording paper by heat and pressure.
When fixing the recording paper, the recording paper comes into contact with the heating roller and the heat of the heating roller is taken away by the recording paper. Therefore, it is necessary to always keep the surface temperature of the heating roller within the usable temperature range. The incandescent lamp for the heat source is used in the blinking mode by an on / off lighting circuit that energizes the lamp intermittently.
[0009]
In the fixing state, it is considered that the continuous heating of the incandescent lamp for the heat source can effectively compensate for the heat of the heating roller taken away by the recording paper. Since the temperature of the heating roller rises excessively, it is used in the flashing mode.
[0010]
Graph A in FIG. 3 shows the temperature characteristics of the surface of the heating roller when the surface temperature of the heating roller rises to the usable temperature range after turning on the main switch of the apparatus when the incandescent lamp 20 for heat source shown in FIG. 2 is used. FIG.
The horizontal axis shows the width in both the left and right directions with the center of the heating roller as the base point (0 mm), and the vertical axis shows the temperature (° C.) of the surface of the heating roller.
As can be seen from the figure, in the effective paper passing area through which the recording paper of the heating roller passes, the temperature at the center of the heating roller and the temperature at both ends of the heating roller are substantially equal, and the surface of the heating roller is substantially uniform. You can see that
[0011]
[Problems to be solved by the invention]
However, in the conventional incandescent lamp for a heat source, the surface temperature of the heating roller rises to the usable temperature range within a short time after the main switch of the apparatus is turned on, and the surface temperature of the heating roller becomes uniform. The amount of heat generated at both ends is made larger than that in the central area, that is, the degree of heating at both ends of the heating roller is made larger than that in the central area to prevent a temperature drop at both ends of the heating roller. In a continuous fixing state where continuous fixing is performed, the surface temperature of both ends of the heating roller becomes relatively higher than the surface temperature of the central region as shown in graph B of FIG. It is known that the surface temperature on the rotary drive gear side becomes extremely high, and the temperature distribution in the longitudinal direction of the heating roller becomes non-uniform.
[0012]
The reason why such a phenomenon occurs is that the surface temperature of the heating roller is detected by a sensor disposed in the central area of the heating roller where heat is taken away by the recording paper, and the incandescent lamp for the heat source is based on the temperature of this part. The surface temperature is kept constant in the central area of the heating roller because the flashing is controlled, but at both ends of the heating roller, the recording paper does not touch the roller and heat is taken away by the recording paper. Originally, both ends of the incandescent lamp for heat source are designed so that the calorific value is larger than that in the central area.In addition, a rotation drive gear and a rotation support member are arranged at both ends of the heating roller. Since the heat from the incandescent lamp for the heat source is gradually accumulated in the rotation drive gear and the rotation support member, and the heat radiation action of the rotation drive gear and the rotation support member is small in the apparatus, the surface of both ends of the heating roller is displayed. Temperature is higher than the surface temperature of the central region, the continuous fixing state, the temperature distribution in the longitudinal direction of the heating roller there is a problem that gradually becomes uneven.
[0013]
Since the rotary drive gear has a larger volume and a larger heat capacity than the rotary support member, the surface temperature of the heating roller on the right side of the rotary drive gear on the right side of the graph B becomes significantly higher as shown in the graph B in FIG. is there.
[0014]
In view of the above problems, the present invention is to provide an incandescent lamp for a heat source that can make the surface temperature of a heating roller uniform even if fixing is performed continuously.
[0015]
[Means for Solving the Problems]
The incandescent lamp for a heat source according to claim 1 is an incandescent lamp for a heat source disposed in a heating roller, and the incandescent lamp for a heat source includes a filament having a light emitting portion disposed in a tube-type bulb, and the tube The light emitting portions located at both ends of the mold bulb generate a larger amount of heat than the light emitting portions located outside the both ends, and a coil is wound around the outer periphery of the central portion of the tubular bulb .
[0019]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described.
4 is a front view of the incandescent lamp for heat source of the present invention, and FIG. 5 is an enlarged partial cross-sectional view of the central region of the incandescent lamp for heat source shown in FIG.
[0020]
In these drawings, 1 is an incandescent lamp for a heat source according to the present invention, and K is a means having a predetermined heat capacity larger than both side regions other than the central portion of the bulb 21, specifically facing the central region light emitting portion 23. This is an external coil wound around the outer periphery of the central portion of the bulb 21.
On one end side of the external coil K, a fixing portion K1 that engages with the exhaust pipe remaining portion 211 of the valve 21 and engages the external coil K with the valve 21 is formed.
Other configurations correspond to the configurations of the same reference numerals shown in FIG.
[0021]
The light emitting portions 22 and 23 and the non-light emitting portions 24 of the filament F are alternately arranged. The non-light emitting portion 24 may be a short-circuited core wire or a filament coil constituting the filament F may be used. A lighter winding than the light emitting units 22 and 23 may be used.
[0022]
The specification of the external coil K uses Kanthal wire with an effective winding number of 16 turns, a coil pitch of 350%, and a coil wire diameter of 0.8 mm outer diameter, and a high melting point made of chromium and iron as the wire. A metal having
[0023]
Here, the coil pitch refers to a factor expressed as b / a, where b is the distance traveled by one turn in a coil having a wire diameter a.
[0024]
As described above, the external coil K is wound around the central portion of the bulb 21 of the incandescent lamp 1 for the heat source as a member having a predetermined heat capacity larger than that of both side regions other than the central portion. Since the incandescent lamp 1 is used in the flashing mode, when the incandescent lamp for heat source 1 is turned off and the heat generation from the filament is stopped, the exothermic heat from the both ends of the incandescent lamp for heat source 1 disappears, but the external coil K is located. The central region of the heat source incandescent lamp 1 is in a state in which heat generation continues while heat dissipation from the external coil K continues.
[0025]
An incandescent lamp for a heat source having such an action is used by being disposed in a heating roller 10 having a rotation drive gear 11 and a rotation support member 12 at both ends shown in FIG. When the surface temperature is equal to or higher than the reference temperature, the heat source incandescent lamp 1 is turned off in order to prevent the temperature of the heating roller 10 from rising excessively.
At this time, the heat supply from the heat source incandescent lamp 1 is not supplied to both ends of the heating roller 10, but in the central region of the heating roller 10, the external coil K wound around the outer periphery of the bulb 21 of the heat source incandescent lamp 10. Heat is being supplied by heat dissipation.
[0026]
Even in such a state, the recording paper is conveyed on the surface of the heating roller 10, and the surface temperature of the heating roller 10 is gradually lowered by the recording paper.
Specifically, in the central region of the heating roller 10, the heat is taken away by the recording paper. However, due to heat radiation from the external coil K in the heating roller 10, the rate of decrease in the surface temperature of the central region of the heating roller 10 can be delayed. In addition, the recording paper does not come into contact with the heating roller 10, and the temperature of the both ends of the heating roller 10 at which heat is not taken away by the recording paper can be adjusted.
That is, the surface temperature of the heating roller 10 can be gradually reduced while maintaining a substantially uniform temperature state in the longitudinal direction of the heating roller 10 while eliminating temperature unevenness.
[0027]
In the fixing state, when the surface temperature of the heating roller 10 becomes equal to or lower than the reference temperature, the heat source incandescent lamp is turned on again.
In this state, the heat generated from both ends of the heat source incandescent lamp 1 is consumed to increase the temperature of the rotation drive gear 11 and the rotation support member 12 at both ends of the heating roller 10, and immediately after lighting, the heating roller 10 is heated. The surface temperature of both ends of the heat source does not increase, and heat generated from the central region of the heat source incandescent lamp 1 is also consumed to increase the temperature of the external coil K. No increase in surface temperature.
[0028]
Thereafter, the incandescent lamp 1 for heat source continues to be lit, and heat is accumulated in the external coil K, resulting in a heat saturation state. At this time, heat is still accumulated in the rotary drive gear 11 and the rotary support member 12, and the rotary drive gear 11 and the rotary support member 12 are not completely in a heat saturation state. ing.
[0029]
Even in such a state, the recording paper is conveyed to the surface of the heating roller 10, and the central area of the heating roller 10 is supplied from the heat taken by the recording paper and the incandescent lamp 1 for the heat source. Although the balance with heat is substantially maintained and the incandescent lamp 1 for the heat source is lit, the surface temperature of the heating roller 10 rises, but the rate of rise is extremely slow as much as heat is taken away by the recording paper. It has become. On the other hand, the rotation drive gear 11 and the rotation support member 12 reach a heat saturation state with a slight delay, and the temperatures at both ends of the heating roller 10 begin to rise.
For a while after this state, the surface temperature of the heating roller 10 gradually increases while the surface temperature of the heating roller 10 does not open in the longitudinal direction, maintaining a substantially uniform temperature state with no temperature unevenness. I will do it.
[0030]
Then, when the surface temperature of the central region of the heating roller 10 reaches the reference temperature by the sensor disposed in the central region of the heating roller, power supply to the incandescent lamp for the heat source is stopped and the incandescent lamp for the heat source is turned off again. .
Note that the lighting time and the lighting time of the incandescent lamp 1 for heat source in the fixing state are, for example, 10 seconds lighting and 2 seconds lighting time, and the lighting time is not extremely long. The incandescent lamp 1 for heat source is extinguished before it becomes extremely high compared to.
In this way, the heat source incandescent lamp is used in the blinking mode during the fixing state.
[0031]
FIG. 5 is a graph showing temperature characteristics of the surface of the heating roller immediately after 20 recording sheets are continuously fixed using the incandescent lamp 1 for heat source of the present invention shown in FIG.
The horizontal axis indicates the width in the left and right directions starting from the center of the heating roller, and the vertical axis indicates the temperature of the heating roller surface.
As can be seen from the figure, in the effective paper passing area through which the recording paper of the heating roller passes, the temperature of the central portion of the heating roller and the temperature of both ends of the heating roller are substantially equal, and the surface of the heating roller remains even after continuous fixing. It can be seen that the temperature is almost uniform.
[0032]
Note that the external coil K used in the present embodiment has a large heat capacity when the pitch width is widened or the wire diameter is narrowed to reduce the volume, and in the fixing state, the temperature distribution in the longitudinal direction of the heating roller. Becomes uneven.
Accordingly, by setting the coil pitch and wire diameter of the external coil K to appropriate values, the temperature distribution in the longitudinal direction of the heating roller in the fixing state can be made uniform.
[0033]
In this embodiment, the external coil K is used as a member for giving a predetermined heat capacity to the central portion of the heat source lamp 1. However, such a member is not limited to the external coil, and other than the central portion. Other members may be used as long as the members have a predetermined heat capacity larger than the both side regions.
[0035]
【The invention's effect】
According to the first aspect of the present invention, an incandescent lamp for a heat source that can make the surface temperature of the heating roller uniform even if continuous fixing is performed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a heating roller.
FIG. 2 is an explanatory diagram of a conventional incandescent lamp for a heat source.
FIG. 3 is a temperature characteristic diagram of the surface of a heating roller using a conventional incandescent lamp for a heat source.
FIG. 4 is an explanatory diagram of an incandescent lamp for a heat source according to the present invention.
FIG. 5 is a temperature characteristic diagram of the surface of the heating roller immediately after completion of the fixing state when the incandescent lamp for heat source of the present invention is used.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Incandescent light bulb 10 for heat sources Heating roller 11 Rotation drive gear 12 Rotation support member 21 Tube-type bulb 22 End light emission part 23 Central area light emission part 24 Non-light emission part 25 Metal foil 26 External lead rod F Filament K External coil

Claims (1)

An incandescent lamp for a heat source disposed in a heating roller,
In the incandescent lamp for heat source , a filament having a light emitting part is disposed in a tubular bulb, and the light emitting parts located at both ends of the tubular bulb have a larger calorific value than the light emitting parts located outside the both ends ,
An incandescent lamp for a heat source , wherein a coil is wound around the outer periphery of the central portion of the tubular bulb .

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