JP2003215964A - Fixation device, heater, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a rush current at an initial energization, as for a heater used for a fixation device for an image forming apparatus. <P>SOLUTION: As to the fixation device 6 for performing thermal fixation with reference to paper Po with an unfixed image by a fixing roll 20 and an endless belt 21, a halogen lamp 25 and a carbon lamp 26 for heating the fixing roll 20 and the halogen lamp 25 and also having the radiant quantity of far infrared radiation larger than that of the halogen lamp 25 are arranged inside the core 20a of the fixing roll 20, and the carbon lamp 26 is arranged mechanically parallel to and near the halogen lamp 25, besides, the carbon lamp 26 is electrically connected to the halogen lamp in series or parallel. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine,
An image forming apparatus such as a laser beam printer or a facsimile machine, and a fixing device used in the image forming apparatus,
The present invention relates to a heater and the like, and more specifically, to an image forming apparatus that performs heat fixing, a fixing device that performs heat fixing, and the like.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a laser beam printer, a facsimile, etc., an electrostatic latent image is formed on a latent image carrier such as a photoconductor belt by a potential distribution according to image information. The electrostatic latent image is developed with toner to form an unfixed toner image on a transfer material, and the toner image formed on the transfer material is heated and melted by a fixing device to be fixed on the transfer material. In such a fixing device, for example, a fixing roll having a built-in heater is provided, and energization control to the heater is performed by a built-in CPU, for example.
It is configured to maintain the temperature of the fixing roll at a predetermined temperature.

On the other hand, halogen heaters are widely used as heating heaters for fixing rolls. The halogen heater is made of, for example, a tungsten resistor. For example, in the first state of the morning when power supply is started from a power-off state, the tungsten is in a cold state and has a very low resistance value. Therefore, if, for example, 100 V is applied,
An inrush current (rush current) of about 80 to 90 A flows at once. As a result, a voltage drop occurs, and the fluorescent lamp flickers, so-called flicker occurs.

As a countermeasure against this flicker, for example, a method has been proposed in which a halogen heater is used as it is and a power thermistor is connected in series to the halogen heater. This power thermistor has a negative temperature-resistance characteristic, that is, the resistance value decreases as the temperature rises, and the temperature of the power thermistor is low and the resistance value is large when the heater is initially energized. With this large resistance value, it is possible to prevent the inrush current generated in the heater. Further, a method has been proposed in which a phase control circuit is provided and phase control is performed for switching a triac that opens and closes an energization circuit for a heater. In this method, for example, the phase angle of the gate signal is gradually increased from the beginning of energization, and the current is gradually increased to control inrush current. Furthermore, for example, JP-A-5-3241
In the publication No. 01, two resistors R1 and R2 are arranged in the heater, and the resistor R1 is provided at the beginning of energization when the temperature of the fixing roll is low.
There is disclosed a technique in which a current is passed through only to suppress the inrush current, and when the temperature of the fixing roll rises, a current is passed through both the resistors R1 and R2 to reduce the combined resistance.

[0005]

However, in the method of connecting the above-mentioned power thermistors in series, when the power thermistor itself is at a low temperature, it works effectively as a measure against flicker, but when it gets warm, the resistance value decreases. Therefore, it cannot be used for temperature control of the fixing roll when the temperature of the power thermistor itself rises, for example, during a normal copy sequence (during continuous sheet feeding).
Further, in the method using the phase control circuit, a high frequency control signal is output due to the necessity of controlling the phase angle, and this signal becomes noise, which adversely affects other circuits and devices. Further, for example, in the technique disclosed in Japanese Patent Application Laid-Open No. 5-324101, the heater structure is complicated and the manufacturing is very difficult.

The present invention has been made in order to solve the above technical problems, and its object is to prevent a rush current at the initial stage of energization in a heater used in a fixing device or the like. To suppress. Another object is to suppress the inrush current even during continuous sheet feeding in the image forming apparatus. Still another object is to maintain a stable heating temperature without requiring complicated temperature control. Still another object is to easily obtain a heat quantity distribution when heating a fixing roll or the like of a fixing device.

[0007]

Based on the above object, the present invention provides a heating member of a fixing device used in an image forming apparatus, for example, by disposing a carbon lamp together with a halogen lamp as a heating element, It is characterized by suppressing inrush current without taking measures such as switching of pseudo resistance, voltage adjustment in transformer, and intervention of power thermistor. That is, the present invention relates to a fixing device that heat-fixes a sheet material having an unfixed image by using a heating member such as a heating roll, a pressure roller, and a predetermined member such as a pressure belt. A first heating element that heats a member and a second heating element that is provided in the vicinity of the first heating element and that heats a predetermined member and that emits far infrared rays in a larger amount than the first heating element. It is characterized by having and.

The second heating element may be a carbon-based heating element or a carbon lamp. Further, if the second heating element is characterized in that the rectangular carbon material is arranged in a state of standing in the vertical direction, it is preferable in that the adverse effect due to the bending of the carbon material can be reduced.

Further, the predetermined member includes a heating roll that rotates in contact with the sheet material, and the first heating element and the second heating element are mechanically provided in parallel inside the heating roll. Can be characterized. Furthermore, this heating roll, by applying an organic substance (e.g., polyimide) to a predetermined location on the inner surface of the core forming the roll (e.g., both end faces), by providing a region where the heat receiving portion is made of at least an organic substance, It is possible to obtain a heat quantity distribution corresponding to the light distribution with respect to the second heating element which is a carbon-based heating element.

Further, the fixing device to which the present invention is applied is a fixing device for heating and fixing a sheet material having an unfixed image, and a heating element having a peak wavelength in the far infrared region, and this heating element. It is characterized in that it is provided with a heating member which is heated by the element and partially contains an organic substance.
Here, the heating member can be characterized in that it is a metal roll in which a part facing the heating element is coated with an organic substance. Further, a belt member coated with an organic substance may be used instead of the metal roll.

On the other hand, the heater to which the present invention is applied is
A first heating element having a resistance value at room temperature lower than that at a high temperature and electrically provided in series or in parallel with the first heating element to suppress an inrush current flowing through the first heating element. In addition, the second heating element, which emits far infrared rays in a larger amount than the first heating element, is provided. Here, the “heater heater” may be in the form of a heater tube (lamp) alone or in the form of a roll having a plurality of lamps incorporated therein. The same applies hereinafter. Further, the second heating element is made of a rectangular carbon material having a wide flat surface portion, and the second heating element is arranged so that the flat surface portion faces the first heating element. It is excellent in that the directivity of the heat generating element can be utilized to positively heat the other heat generating element, which is the first heat generating element.

From another point of view, the heater to which the present invention is applied includes a glass tube, a filament provided inside the glass tube for outputting light of a predetermined wavelength, and the glass tube. It is characterized in that a carbon material mechanically provided in parallel or in series with the filament is provided inside.

On the other hand, an image forming apparatus to which the present invention is applied includes sheet conveying means for conveying a sheet, image forming means for forming an image on the sheet conveyed by the sheet conveying means, and this image forming means. A sheet on which an image is formed by means of heat fixing, and the fixing means comprises a plurality of heating elements having different emission wavelengths.
(For example, a carbon lamp, which is a carbon-based heating element, and a halogen lamp) are used for heating.

Further, an image forming apparatus to which the present invention is applied is
A fixing unit that heats and fixes a sheet on which an image is formed by the image forming unit and is heated by a carbon lamp that is a carbon-based heating element, and the carbon lamp is energized when the power to the fixing unit is turned on; It is characterized by suppressing the inrush current to the.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the accompanying drawings. FIG. 1 is a diagram showing an overall configuration of an image forming apparatus to which this exemplary embodiment is applied. In the image forming apparatus shown in FIG. 1, a post-processing apparatus 13 is shown together with a main body side that forms an image by an electrophotographic method. On the main body side, the photoconductor belt 1, which is a latent image carrier whose conductivity changes by irradiation with light, the charging roll 2 that charges the photoconductor belt 1, and the photoconductor belt 1 are irradiated with light reflected by the original Ps. For the exposure system member 3, the developing device 4 for supplying the charged toner to the photosensitive belt 1, the transfer roll 5 for applying the transfer voltage to the photosensitive belt 1 at the transfer position, and the sheet (sheet material) Po on which the image is formed. That is, for fixing the unfixed toner image transferred on the paper Po by fixing it by heating and pressurizing it, the cleaning device 7 for cleaning the photoconductor belt 1 after the transfer, and the charge removal for the photoconductor belt 1 after the cleaning. A static elimination lamp 8 is provided. The exposure system member 3 includes a platen glass 3a on which an original Ps is placed, an exposure lamp 3b which moves while irradiating the original Ps with light, and light reflected from the original Ps on the photosensitive belt 1.
An optical element 3c for forming an image at a predetermined position above is provided.

The image forming apparatus also includes a document tray 9
An automatic document feeder 9 for supplying a plurality of documents Ps placed on a to the platen glass 3a, and a sheet tray 10 for stacking and accommodating sheets Po as transfer materials (sheet materials),
The paper tray 10 has different types and sizes of paper P.
Multiple stages are arranged so that o can be loaded. Also,
The paper tray 10 is provided with a manual feed tray 11 used for stacking paper Po of a size and type different from the paper tray 10, a paper feed path 12 for carrying the paper Po fed from the paper tray 10, and the manual feed tray 11. This paper transport path 12
Provides a reversing conveyance path that reverses and conveys the paper Po discharged from the fixing device 6 and enables double-sided printing. Further, in the post-processing device 13 that performs post-processing on the printed paper Po on the main body side, the top tray 13a for outputting the paper Po after fixing without performing post-processing, and performing the accumulation and sorting. At that time, a bin tray 13b that forms a sorter of 20 bins and a stapler 13c that staples the paper Po are provided. In addition, a liquid crystal display as a touch panel having a predetermined size is provided, and a user interface device 14 for setting the image forming apparatus by touching the liquid crystal display is provided.

FIG. 2 is a diagram for explaining the configuration of the fixing device 6 to which this embodiment is applied. This fixing device 6
As its main part, first, the fixing roll 20 which is heated and used, and the paper P facing the fixing roll 20.
An endless belt 21 for pressurizing o and a pressure pad 22 arranged in a state of being pressed by the fixing roll 20 via the endless belt 21 are provided. Further, in the present embodiment, as the heating member (heating element) of the fixing roll 20, a halogen lamp 25 made of tungsten and a carbon (carbon) material having a rectangular shape (plate shape) that emits light in the far infrared region are used. The carbon lamp 26 and the halogen lamp 25, which are system heating elements, are provided with a reflecting member 27 for actively warming the carbon lamp 26. In FIG. 2, the halogen lamp 25 and the carbon lamp 26 are mechanically arranged in parallel, and are electrically connected in series or in parallel.
Further, the belt running guide 23 and the fixing roll 2 which are used so that the endless belt 21 smoothly slides and rotates.
A temperature sensor 24 for measuring the surface temperature of 0, and a peeling member 2 for peeling the fixed paper Po from the fixing roll 20.
Eight. Although not shown, the halogen lamp 2
5 and the carbon lamp 26 may be electrically connected in series, for example, by connecting one terminal of both the halogen lamp 25 and the carbon lamp 26 and establishing conduction from the other terminal of each. To be Further, as a method of electrically connecting in parallel, a halogen lamp 2
5 and the carbon lamp 26, both terminals may be connected, and conduction may be established from both terminal sides of either lamp.

The halogen lamp 25 is a glass tube containing an inert gas such as nitrogen or argon together with a trace amount of a halide.
It is an incandescent light bulb in which (iodine, bromine, chlorine, fluorine) is enclosed, and has a high radiation intensity characteristic in the near infrared region with a peak wavelength of, for example, about 1.7 μm. In the carbon lamp 26 provided mechanically in parallel with the halogen lamp 25, the peak wavelength is in the far infrared region (especially 2.5 to 8 μm).
m), the radiation amount of far infrared rays is increased by, for example, about 30% or more as compared with the halogen lamp 25. Further, the carbon lamp 26 has a rapid heating property that reaches the maximum temperature several seconds after the switch is turned on. The infrared rays are electromagnetic waves having a lower limit of 0.76 to 0.83 μm at the long wavelength end of visible light and an upper limit of about 1 mm, for example, a wavelength of 2.
It is possible to classify 5 μm or less as near infrared rays and 2.5 μm or more as far infrared rays. Organic substances including the human body have a property of easily absorbing heat in the far infrared wavelength region.

The fixing roll 20 includes a metal core 20a which is a cylindrical core metal, a heat-resistant heat insulating layer 20b provided around the core 20a, and the heat-resistant heat insulating layer 20.
A release layer (heat resistant resin layer) 20c provided around b is provided. The core 20a, the heat resistant heat insulating layer 20b and the release layer 20c are rotated in the direction of arrow B by a motor (not shown) as a fixing rotating body. The core 20a functions as a base material of the fixing rotating body, and is made of, for example, aluminum having a thickness of about 3 mm. Besides aluminum,
A metallic cylindrical body having high thermal conductivity such as iron or stainless steel can be used. In the case of iron, for example, an outer diameter of 20 to
It is possible to use one having a thickness of about 35 mm and a wall thickness of about 0.3 to 0.5 mm. Of course, since the strength and the thermal conductivity differ depending on the material used, the optimum size can be appropriately determined. As will be described later, this core 20
The inner surface of a is coated with an organic substance such as polyimide in order to ensure a predetermined heat generation distribution when the carbon lamp 26 is used.
Can be (coated). The surface temperature of the fixing roll 20 is measured by a temperature sensor 24, and the fixing controller 2 is operated by a temperature controller (not shown).
Halogen lamp 25 so that the surface temperature of 0 is constant
The carbon lamp 26 is feedback-controlled.

As the heat-resistant heat insulating layer 20b formed on the surface of the core 20a, an elastic body having high heat resistance, for example, an elastic body such as rubber or elastomer having a rubber strength of about 25 to 40 ° (JIS-A), Specifically, silicone rubber, fluororubber, or the like can be used. In addition, the heat resistant heat insulating layer 20
As the release layer 20c formed on b, a fluororesin or a silicone resin is used in consideration of releasability and abrasion resistance. From the viewpoint of suppressing the occurrence of wrinkles and the occurrence of image quality defects such as uneven gloss, the release layer 20c can be formed to a thickness of 5 to 30 μm, more preferably 10 to 20 μm. .

The endless belt 21 is the fixing roll 20.
The nip portion is formed by making contact with each other so as to be wound at a predetermined angle. This endless belt 21
For example, it is composed of a base layer and a release layer coated on the surface thereof (the surface in contact with the fixing roll 20 or both surfaces). The base layer is selected from polyimide, polyamide, polyamideimide and the like, and has a thickness of, for example, about 50 to 125 μm. The release layer is coated with a fluororesin such as PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin) in a thickness of 5 to 20 μm.

The pressure pad 22 disposed inside the endless belt 21 is an elastic member 22a for ensuring a wide nip portion, and a low friction layer provided on the surface of the elastic member 22a that contacts the endless belt 21. Two
2b, a peeling nip member 22d arranged on the exit side of the nip portion for giving a distortion to the fixing roll 20, and is held by, for example, a metal holder 22c. The elastic member 22 a is formed in a concave shape that substantially follows the outer peripheral surface of the fixing roll 20, and causes the fixing roll 20 to have a certain distortion. The endless belt 21 is driven to rotate by the rotation of the fixing roll 20.

The unfixed toner image T is transferred onto the paper Po conveyed through the transfer roll 5 shown in FIG. 1, and the paper Po is conveyed toward the nip portion in the direction of arrow A shown in FIG. It Paper Po inserted into the nip and conveyed
Is fixed by the pressure acting on the nip portion and the heat given through the fixing roll 20 by the halogen lamp 25 and the carbon lamp 26. At that time, stable fixing performance is secured by the pressure pad 22 and the endless belt 21, and the distortion of the fixing roll 20 is locally increased by the peeling nip member 22d, so that a high releasing performance is obtained with a small amount of distortion. It is possible to suppress the generation of wrinkles even when the thin film release layer 20c is provided.

Next, the heating of the fixing roll 20 will be described. As described above, inside the fixing roll 20, a plurality of types of lamp heaters, such as the halogen lamp 25 and the carbon lamp 26, having different corresponding wavelength regions as radiation intensity characteristics are arranged. In the case where the halogen lamp 25, which has been widely used as a heating material for an image forming apparatus in the past, is a single body, it is necessary to take special measures against a rush current at the time of power input to the tungsten wire. In the present embodiment, the carbon lamp 26 and the halogen lamp 25 are arranged inside the fixing roll 20, and the carbon lamp 26 and the halogen lamp 25 are electrically connected in series or in parallel, so that the rush No special measures against electric current are required. Here, the inrush current is, for example, a current that flows at a value several times to several tens of times the rated current value when the halogen lamp 25 is powered on. For example, the tungsten wire that is the heating element of the halogen lamp 25 is at room temperature. Occurs due to the small resistance value.

3 (a) and 3 (b) are views showing the structure of the carbon lamp 26 used in the present embodiment. FIG. 3 (a) is a perspective view of the carbon lamp 26, and FIG. FIG. 2B is a sectional view showing a state in which the carbon lamp 26 is attached inside the fixing roll 20. In the carbon lamp 26, a transparent quartz tube 31 is provided with a heating element 33 made of a rectangular carbon material having both ends supported by tungsten coils 32. It is known that carbon (charcoal) which is a black body has a high emissivity for far infrared rays. In this carbon lamp 26, a carbon material is used for the heating element 33 to increase the far infrared radiation amount. . Also, with this carbon lamp 26,
As mentioned above, the peak wavelength is in the far infrared region (especially 2.5-8μ).
m), and has the characteristic that the radiation intensity of far infrared rays is high in the absorption wavelength range of organic substances. Furthermore, it has a rapid heating property that reaches the maximum temperature several seconds after the power is turned on.

In the present embodiment, this carbon lamp 2
By arranging 6 to face the halogen lamp 25 and connecting them in series or in parallel, the rush current generated in the halogen lamp 25 due to the resistance of the carbon lamp 26 is suppressed by the same function as the power thermistor immediately after the power is turned on. can do. As a result, it is possible to suppress flickering of the fluorescent lamp that occurs when the power is turned on. Further, when the carbon lamp 26 is warm, the resistance value does not decrease because the heating element of the halogen lamp 25, tungsten, is warm. That is, during normal operation (during continuous paper feeding, copy sequence), the carbon lamp 2
Even if the temperature of 6 rises, the other heating source that opposes is heated, so that the rush current of the other heating source can be prevented and the flicker prevention function can be enhanced. In addition, in the present embodiment, FIG.
The reflecting member 27 shown in FIG. This reflecting member 27
Is used to increase the directivity of the carbon lamp 26. By positively warming the halogen lamp 25, the tungsten filament in the halogen lamp 25 is accelerated in heating, and the resistance value is increased to increase the inrush current. Further strengthening prevention.

Here, as shown in FIG. 3B, when the carbon lamp 26 is attached to the fixing roll 20, the rectangular heating element 33 is placed vertically, that is, the cross-sectional longitudinal direction of the heating element 33. Are arranged so as to be substantially in the same direction as the vertical direction. When the longitudinal cross section of the heating element 33 is arranged in a direction orthogonal to the vertical direction, that is, when the heating element 33 is placed horizontally, the heating element 33, which is a carbon plate member, bends due to its own weight, and the heating element 33
In some cases, the central portion in the tube longitudinal direction may contact the inner wall of the transparent quartz tube 31. By disposing the heating element 33 at the position shown in FIG. 3B, it is possible to prevent the bending of the heating element 33 from coming into contact with the inner wall of the transparent quartz tube 31. This also makes it possible to reduce the lamp shape. Further, since the heating element 33 has a rectangular shape, it has directivity, that is, by directing the flat surface of the heating element 33, which is a rectangular member having a wide flat surface, to the halogen lamp 25 side, It is possible to positively heat the halogen lamp 25, which is a heating element, and to enhance the flicker prevention function even during continuous sheet feeding, for example. As shown in FIG. 2, when the carbon lamp 26 is arranged in parallel beside the halogen lamp 25,
By raising a rectangular member as shown in FIG. 3B, it becomes possible to secure such directivity.

In FIG. 2, one carbon lamp 26 is provided for the halogen lamp 25 and the carbon lamp 26 is arranged on the fixing roll 20. However, the number of carbon lamps 26 is increased to a plurality (for example, 2 to 3). ) Carbon lamp 26
It is also possible to arrange the halogen lamp 25 so as to surround it. As for the arrangement, in addition to the case where the lamps are arranged side by side, the lamps may be arranged in a pyramid shape or the like. That is, a plurality of lamps having different emission wavelengths can be freely combined and used as a heating member.

As described above, the technique to which the present embodiment is applied incorporates a plurality of heating elements (halogen lamp 25 and carbon lamp 26) that generate heat when energized, and energizes all of these heating elements. And a heating control method using a heating element that is switchably provided such that only a part of the heating element can be energized. At this time, in a state where the carbon lamp 26, which is a carbon-based heating element, is partially used, by energizing all the heating elements at the start of heating,
The inrush current can be reduced in the same manner as when the power thermistor is introduced. Further, during continuous sheet feeding, even if the temperature of the carbon lamp 26 rises, since another heating source is heated as a heater, it is possible to prevent an inrush current of the other heating source.

FIGS. 4 (a) and 4 (b) are views showing an application example of the present embodiment, and the halogen lamp 2 shown in FIG.
5 and carbon lamp 26, instead of fuser roll 2
Inside the 0, a single tube having these functions is provided as a heater. FIG. 4A is a plan view, and FIG. 4B shows a cross section H-H of FIG. 4A. Here, a carbon material 41, which is a carbon heater, and a tungsten filament 42, which is a halogen heater, are arranged in parallel (mechanically in parallel) in a glass tube 40 having an elliptical shape. Inside the tube 40, nitrogen of 2 atm and bromine gas of several PPM as a halide are enclosed. The carbon material 41 has the same structure as the heating element 33 of the carbon lamp 26 shown in FIG.
The tungsten filament 42 is used for the halogen lamp 25.
It has a structure similar to that of the light-emitting body existing inside.
For example, 100V, 300W carbon material 41 and 100V, 35
A 100 V, 750 W heater can be constructed by electrically connecting the 0 W tungsten filament 42 in series. Of course, it is also possible to electrically connect them in parallel. As a method of electrically connecting in series, two terminals at one end of the heater shown in FIG. 4A may be connected and power may be supplied from the two terminals at the other end. Further, as a method of electrically connecting in parallel, two terminals at both ends may be connected to each other, and electric power may be supplied from arbitrary terminals at both ends of the heater.

When the power of the image forming apparatus is turned on, the carbon material 4
1 is rapidly heated, warming the tungsten filament 42. The carbon material 41 functions similarly to a power thermistor, can prevent generation of an inrush current to the tungsten filament 42, and can suppress flicker. Further, even if the temperature rises during continuous paper feeding, it is possible to suppress the inrush current by heating the tungsten filament 42. As shown in FIG. 4 (b), the carbon material 41 is a rectangular member having a wide flat portion, and the flat surface portion is arranged so as to face the tungsten filament 42. By effectively utilizing the directivity of the tungsten filament 42, the tungsten filament 42 can be actively heated.

5 (a) and 5 (b) are diagrams showing another application example of the present embodiment. In FIGS. 5A and 5B, a carbon material 51 and a tungsten filament 52 are mechanically arranged in series inside a glass tube 50 as a heater.
These are also electrically connected in series. Also, FIG.
In (a), carbon material 51 is provided at both ends of the glass tube 50, and a tungsten filament 52 is provided in the central portion.
Then, the tungsten filaments 52 are provided at both ends of the glass tube 50, and the carbon material 51 is provided at the central portion. Even when the carbon material 51 and the tungsten filament 52 are arranged in series (mechanically in series) as shown in FIGS. 5 (a) and 5 (b), As in the case of arranging in parallel (mechanically in parallel) as shown, it is possible to suppress flicker while reducing thermal loss.
The lengths (ratio) of the carbon material 51 and the tungsten filament 52 can be arbitrarily determined depending on how they are used.

FIGS. 6A and 6B are views showing still another application example. Here, an example is shown in which the polyimide 60, which is an organic substance, is applied to the inner surfaces of both end surfaces of the core 20a of the fixing roll 20 shown in FIG. In this example, the core 20a has a predetermined length (for example, about 5c) from both end surfaces.
m), the polyimide 60 is coated to a thickness of about 30 μm. The halogen lamp 25 can secure a desired light distribution by modifying the shape of the filament provided inside, but the carbon lamp 26 is a carbon sintered body similar to the pencil lead. However, the shape cannot be easily deformed and processed, and it is difficult to provide a light distribution. On the other hand, since the wavelength of the carbon lamp 26 is shifted to the far infrared side,
Absorption is higher with organic substances than with metals. Therefore, in this application example, the polyimide 60, which is an organic substance, is applied in conformity with the heat generation distribution to be obtained, and the polyimide 60 is better than the metal.
Since the side is heated, the heat generation distribution of the fixing roll 20 can be easily created even when the orientation distribution is not created on the lamp side. That is, as shown in FIG.
By applying polyimide 60 to both ends of "a", as shown in FIG.
As shown in FIG. 5, it is possible to generate a heat generation distribution in which both ends of the core 20a become high temperature, and when the fixing roll 20 is attached to the main body of the apparatus, for example, heat escapes from both end sides of the core 20a via a mechanism part or the like. Fuser roll 2
It is possible to secure a uniform temperature as a whole.

As described above, in the present embodiment,
Halogen lamp 25, carbon lamp 26, glass tube 4
A plurality of heating elements having different emission wavelength regions, such as carbon materials 41 and 51 and tungsten filaments 42 and 52, which are provided at 0 and 50, are built in, for example, the fixing roll 20, and all heating elements are energized at the start of heating. Configured. The carbon lamp 26, which is a carbon-based heating element having a high emissivity of far infrared rays, and the carbon materials 41 and 51 have the same effect as that of connecting the power thermistor to the halogen lamp 25 and the tungsten filaments 42 and 52 at the start of heating. Obtainable. For example, with the halogen lamp 25 (tungsten filaments 42, 52) alone, a rush current of 80 A is usually generated at the start of heating,
By providing the carbon lamps 26 (carbon materials 41, 51), almost no inrush current is generated, and the occurrence of flicker at the start of heating can be suppressed. Also,
During normal use (during the copy sequence), the halogen lamp 25 (tungsten filament 42, 52) is heated by the carbon lamp 26 (carbon material 41, 51) and can be heated. It is possible to reduce the resistance value of 52) and prevent the generation of inrush current. Furthermore, for example, by arranging the heating element 33 of the carbon lamp 26 in the vertical direction and mechanically arranging the halogen lamps 25 in the horizontal direction, it is possible to enhance the heating effect by the directivity of the heating element 33. Become. Further, by providing the reflecting member 27 and effectively heating the halogen lamp 25 by the carbon lamp 26, this heating effect can be further enhanced.

When a heating element such as a carbon lamp 26 having a high emissivity of far infrared rays such as a carbon material is used among a plurality of heating elements having different emission wavelength regions, heat absorption for far infrared rays is performed. By effectively using the property of “organic matter” having high characteristics, the heat quantity receiving portion is provided with a region composed of at least organic matter, and for example, an organic matter such as polyimide 60 is formed on the inner surface of the core 20a in the fixing roll 20 including the carbon lamp 26. By applying, it is possible to easily obtain the required heat generation distribution. In such cases,
For example, unlike the halogen lamp 25, it is not necessary to have the orientation distribution on the lamp side.

In this embodiment, a plurality of heating elements including a carbon-based heating element are provided on the fixing roll 20 side, but they may be provided on the pressure side of the endless belt 21 or the like. Further, the fixing device 6 is not limited to the structure shown in the present embodiment, and a pressure roll may be used instead of the endless belt 21, and such a pressure roll as shown in this embodiment. It can also be configured to include a different heating element. Furthermore, for parts other than the fixing device 6 where it is desired to suppress flicker when the power is turned on,
It is also possible to apply the technique described in this embodiment.

[0037]

As described above, according to the present invention, in the heater used for the fixing device or the like, it is possible to suppress the inrush current at the initial stage of energization.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an image forming apparatus to which this exemplary embodiment is applied.

FIG. 2 is a diagram for explaining a configuration of a fixing device to which the exemplary embodiment is applied.

3 (a) and 3 (b) are diagrams showing a configuration of a carbon lamp used in the present embodiment.

4A and 4B are diagrams showing an application example of the present embodiment.

5A and 5B are diagrams showing another application example of the present embodiment.

6A and 6B are diagrams showing still another application example.

[Explanation of symbols]

1 ... Photosensitive belt, 2 ... Charging roll, 3 ... Exposure system member,
4 ... Developing device, 5 ... Transfer roll, 6 ... Fixing device, 7 ... Cleaning device, 8 ... Discharge lamp, 10 ... Paper tray,
11 ... Manual feed tray, 12 ... Paper transport path, 13 ... Post-processing device, 20 ... Fixing roll, 21 ... Endless belt, 2
2 ... Pressure pad, 23 ... Belt running guide, 24 ... Temperature sensor, 25 ... Halogen lamp, 26 ... Carbon lamp, 27 ... Reflecting member, 28 ... Peeling member, 31 ... Transparent quartz tube, 32 ... Tungsten coil, 33 ... Heat generation Body, 40 ...
Glass tube, 41 ... Carbon material, 42 ... Tungsten filament, 50 ... Glass tube, 51 ... Carbon material, 52 ... Tungsten filament

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 3/14 H05B 3/14 F 3/44 3/44 F term (reference) 2H033 AA03 AA41 BA25 BA26 BB18 BB21 CA30 CA44 3K058 AA27 AA88 BA18 CB01 CE03 CE13 CE17 CE21 CE28 CE29 DA02 DA06 GA06 3K092 PP18 QA05 QB02 QB14 QB32 QB48 QB49 QB65 RA03 RD11 VV21 VV30

Claims (14)

[Claims] 1. A fixing device for heating and fixing a sheet material having an unfixed image using a predetermined member, comprising: a first heating element for heating the predetermined member; and a first heating element. A fixing device comprising: a second heating element which is provided in the vicinity and heats the predetermined member, and emits far infrared rays in a larger amount than the first heating element. 2. The fixing device according to claim 1, wherein the second heating element is a carbon-based heating element. 3. The fixing device according to claim 1, wherein the second heating element is arranged in a state where a rectangular carbon material is erected in a vertical direction. 4. The predetermined member includes a heating roll that rotates in contact with the sheet material, and the first heating element and the second heating element are mechanically arranged in parallel inside the heating roll. The fixing device according to claim 1, wherein the fixing device is provided. 5. The fixing device according to claim 4, wherein the heating roll has an organic substance at a predetermined position on the inner surface of the core forming the roll. 6. A fixing device for heating and fixing a sheet material having an unfixed image, the heating element having a peak wavelength in a far infrared region, and an organic substance partially heated by the heating element. And a heating member having a fixing member. 7. The fixing device according to claim 6, wherein the heating member is a metal roll having a portion facing the heating element coated with an organic material. 8. A first heating element having a resistance value at room temperature lower than that at a high temperature, and a first heating element provided electrically in series or in parallel with the first heating element and flowing to the first heating element. A heater comprising: a second heating element for suppressing an inrush current. 9. The heater according to claim 8, wherein the second heating element emits far infrared rays in a larger amount than the first heating element. 10. The second heating element is made of a rectangular carbon material having a wide flat portion, and is arranged such that the flat portion faces the first heating element. Item 8. A heater according to item 8. 11. A glass tube, a filament provided inside the glass tube for outputting light of a predetermined wavelength, inside the glass tube, mechanically in parallel or in series with the filament. A heater comprising: a carbon material provided. 12. A sheet conveying means for conveying a sheet, an image forming means for forming an image on the sheet conveyed by the sheet conveying means, and a heating for a sheet on which an image is formed by the image forming means. An image forming apparatus comprising: a fixing unit configured to perform fixing, wherein the fixing unit is heated by a plurality of heating elements having different emission wavelengths. 13. The image forming apparatus according to claim 12, wherein the fixing unit includes a carbon lamp that is a carbon-based heating element and a halogen lamp. 14. A sheet conveying means for conveying a sheet, an image forming means for forming an image on the sheet conveyed by the sheet conveying means, and a carbon lamp which is a carbon-based heating element for heating to form the image. A fixing unit that heats and fixes a sheet on which an image is formed by means, and the carbon lamp is energized when a power supply to the fixing unit is turned on to suppress an inrush current to the fixing unit. Image forming apparatus.