JP2001337554A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously realize the accurate control of two heaters, the prevention of the damage caused by the contact of a temperature sensor in the paper passing area of a heating roll, the restraint of soil caused by the adhesion of toner or the like to the temperature sensor and the prevention of the occurrence of faulty fixation or the wrinkles of paper caused by a temperature difference even when the fixation is performed to large size recording paper just after consecutively performing the fixation to small size recording paper in a fixing device where the heating roll is heated by two heaters. SOLUTION: The heaters respectively heating the bisected paper passing areas of the heating roll 10 are used as two heaters 20 and 30, and the energizing of the two heaters is controlled according to detection information by two temperature sensors 40 and 50 properly installed in the paper non-passing area of the roll 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as a copying machine, a printer, a facsimile, etc., which forms an image by thermally fixing an unfixed image on recording paper. In particular, the present invention relates to a fixing device of a type in which a heating rotating body such as a heating roll for heating an unfixed image on recording paper is heated by two heaters.

[0002]

2. Description of the Related Art A fixing device of this type basically has a rotating cylindrical heating roll 100 as shown in FIG.
And two heaters 110 and 1 installed inside the heating roll 100 to heat the roll surface to a required temperature.
20 and a recording paper carrying an unfixed image (for example, an unfixed toner image) is passed through the surface of the heating roll 100 heated by at least one of the heaters 110 and 120 so as to contact the surface thereof. Fixing is performed by heating the image (JP-A-8-220930).
Issue publication). W in the drawing indicates a maximum sheet passing area which is an area through which the largest recording sheet comes into contact with and passes through the heating roll 100. Further, the heater 110 is an energization heating type heater configured to heat the maximum paper passing area W of the heating roll 100, and the heater 120 is a heating roll 1
An electric heating type heater configured to heat a small-size sheet passing area, which is an area through which a small-size recording sheet abuts and passes, among 00.

The two heaters 110,
For example, as shown in FIG. 9, the temperature control in the fixing device that heats the heating roll 100 by the heating roller 120 is performed by providing a temperature sensor 130 that contacts the vicinity of the center of the surface of the heating roll 100 and detects the surface temperature. Sensor 130
Control device (information processing device) 14
0, and based on the temperature information, the controller 140 controls the heaters 110 and 120 to be energized (for example, ON).
/ OFF operation) is appropriately controlled. Thereby, the heating operation of each heater is controlled, and the heating roll 100 is heated and maintained at a required temperature. 150 and 160 in the figure are control devices 1
In response to the control signal from the power supply 40, the heater 110,
This is a driver that independently controls each energizing operation to 120.

[0004]

The fixing device of the type in which the heating roll is heated by the two heaters has the following problems.

First, two heaters 110 and 120 are used based only on temperature information detected by one temperature sensor 130.
When controlling the energizing operation of the temperature sensor 130,
If there is a heater that mainly heats only an area different from the surface portion of the heating roll 100 detected in (1), the heating roll heated by the corresponding heater (120) is used. Since the surface temperature at a position away from the region is detected by the temperature sensor 130, it is difficult to accurately control the temperature of the heater (120). As a countermeasure, a temperature sensor 170 for detecting the surface temperature in the area of the heating roll 100 heated by the corresponding heater (120) is separately provided as exemplified by a two-dot chain line in FIG. It is also conceivable to independently control the energizing operation of the heater (120) based on the temperature information detected by the temperature sensor 170.

However, when two heaters are controlled by using one temperature sensor 130, two temperature sensors 13 are used.
Regardless of the case of individually controlling the temperature sensors using the temperature sensors (130, 170),
170) is provided so as to abut within the maximum paper passing area W of the heating roll 100, and thus has the following problem. That is, the surface portion of the heating roll 100 in the paper passing area where the temperature sensors (130, 170) come into contact may be damaged, and image quality may be deteriorated due to the damage. In addition, toner, paper dust, and the like existing in the paper passing area of the heating roll 100 adhere to the detection surface of the temperature sensor, and the detection surface is easily stained. As a result, it is difficult to accurately detect the surface temperature. It is also difficult to accurately control the heater. Further, when the recording paper at the time of fixing is wound around the heating roll 100, the wound recording paper may be clogged by the temperature sensor, or it is difficult to accurately detect the temperature by the temperature sensor at the time of the winding. there were.

Further, when fixing is performed on a large-sized recording sheet immediately after fixing on a small-sized recording sheet is continuously performed, the small-size sheet passing area of the heating roll 100 is set to a small-sized heater 120. Is heated by the heater 110 after being heated by the heater 110, but fixing is performed on a large-size recording sheet in a state where the sheet-passing area other than the small-size sheet passing area is not sufficiently heated. Therefore, due to the temperature difference in the sheet passing area, a fixing failure may occur, or paper wrinkles may occur on a large-size recording sheet.

In a general fixing device, the heating roll 100 is rapidly heated to a temperature at which fixing can be performed at the start of use or when the use is resumed after a long standby.
A so-called warm-up operation is performed, and it is desired that the time required for the warm-up be reduced as much as possible. Incidentally, in order to shorten the time required for warm-up in a fixing device of the type described above, for example, a method of simultaneously heating the two heaters 110 and 120 may be considered. Since the small-size sheet passing area of the maximum sheet passing area W of the heating roll 100 is heated by the two heaters 110 and 120, the other sheet passing areas are heated only by the heater 110. However, only the small-size paper passing area is rapidly heated, and the maximum paper passing area is not heated uniformly over the entire area.

The present invention has been made in view of such circumstances, and has as its object to provide a fixing device capable of solving all of the above-described problems.

[0010]

The fixing device of the present invention, which can achieve the above object, comprises a heating rotator for heating an unfixed image carried on a recording sheet passing therethrough, and a heating rotator for heating the unfixed image. Of the two divided paper passing areas obtained by dividing the maximum paper passing area, which is the area through which the largest width recording paper abuts, passes,
An electrically heated first heater for heating one of the divided paper passing areas to a required surface temperature, and an electrically heated second heater for heating the other divided paper passing area to a required surface temperature; Of the two non-sheet passing areas, which are areas adjacent to the outside of both ends of the maximum sheet passing area of the heating rotator and through which recording paper does not pass, a non-sheet passing area adjacent to the one divided sheet passing area. A first temperature detector for detecting the surface temperature by contacting the paper area, and a second temperature detector for detecting the surface temperature by contacting the non-sheet passing area adjacent to the other divided sheet passing area And first control means for controlling an energizing operation to the first heater based on temperature information detected by the first temperature detector; and temperature information detected by the second temperature detector. Control means for controlling the energization operation to the second heater based on And it is characterized in and.

The recording paper may be any recording material capable of thermally fixing an unfixed image. Specifically, in addition to general recording paper, OHP sheets, cardboard including postcards, envelopes and the like It is. The unfixed image only needs to be fixed on the recording paper by being heated, for example,
This is a toner image obtained by developing with a developer. The heating rotator is usually in the form of a cylindrical roll, but may be in the form of a belt that rotates while being supported by a support member disposed on the inner peripheral surface side of the belt serving as a fixing area. Good. The width dimension (division condition) of the two divided paper passing areas in the heating rotator is appropriately selected based on the type of the width size of the recording paper used for fixing (width dimension at the time of conveyance), the frequency of use, and the like.

The two heaters need only generate heat when energized, and include, for example, a heating wire wound in a coil shape and a heating lamp shape.
These two heaters only need to have a heat-generating (heating) portion for heating at least each of the divided sheet passing areas to be heated. Usually, heat-generating portions are formed only at positions corresponding to the respective divided areas. A heat-generating part may be used, but the heat-generating part may be arranged so as to cover the heat insulating member at a portion facing the divided paper passing area where heating is unnecessary. The temperature detector may be anything that can contact the surface of the heating rotator to detect the surface temperature, and is, for example, a contact-type temperature sensor. The control means only needs to be able to independently control the energizing operation to each heater while comparing each temperature information detected by each temperature detector with each preset threshold value for temperature control.

According to such a fixing device, the heating rotary body is heated by the first heater in one of the two divided sheet passing areas of the maximum sheet passing area, and the other divided sheet passing area is heated by the first heater. Heated by the second heater. These two heaters are independently controlled based on temperature information of a total of two temperature detectors which are arranged separately in each divided paper passing area heated by each heater and each non-paper passing area adjacent thereto. Is done. As a result, each of the heaters individually detects the surface temperature of each of the divided paper-passing areas and the adjacent non-paper-passing areas that are specially heated by the heater, and independently controls each of them based on the detected information. Therefore, accurate control is possible. In addition, since the two temperature detectors are both disposed in the non-paper passing area, no damage is caused in the paper passing area of the heating rotator due to the contact of the temperature detectors, and the detection surface is formed of toner. ,
The rate of fouling due to the adhesion of paper powder etc. decreases,
Even if the recording paper is wrapped around (the paper passing area of) the heating rotator, there is no problem in detecting the surface temperature.

Further, in the above-mentioned fixing device, the first
Is configured to heat the one divided sheet passing area and at the same time to heat the other divided sheet passing area to a temperature lower than the required surface temperature, and the second heater includes: It is preferable that the other divided sheet passing area is heated to a temperature lower than the required surface temperature at the same time as the other divided sheet passing area is heated.

In this case, even when heating is performed by only one heater, the divided sheet passing area to be heated by the other heater is also preliminarily heated to a relatively low temperature. Thereby, even if the fixing that requires the heating of both heaters is performed immediately after the fixing that requires only the heating of one of the heaters is continuously performed, the preliminary heating described above is performed. The temperature difference in the maximum paper passing area is relatively small, and the occurrence of fixing failure and the occurrence of wrinkles on the recording paper are reduced.

Further, in a fixing device in which the respective heaters can be heated to some extent simultaneously in the divided sheet passing area to be heated by the counterpart heater, the heating characteristics of the first heater and the heating characteristics of the second heater can be improved. The heating characteristics are first
It is preferable that the distribution of the surface temperature in the maximum sheet passing area of the heating rotator is substantially symmetrical when the heating by the heater and the second heater is performed simultaneously. The distribution setting for the heating characteristics of each heater is as follows:
For example, it can be performed by adjusting the heat generation ratio (ratio) of the heat generation portion of each heater. In particular, the heat generation rate of the corresponding portion of each heater that heats a region that is the boundary between the two divided paper passing areas in the heating rotator gradually decreases as it goes in the direction of entering the divided paper passing area heated by the other heater. It is desirable to adjust the characteristics so that they intersect on the way.

In this case, when simultaneous heating is performed by two heaters, each divided sheet passing area of the heating rotator is shared and heated by each heater, and at the same time, the other divided heating area is heated. The paper passing areas are also heated to some extent. In addition, the two heaters are heated in a well-balanced manner at the boundary between the divided sheet passing areas, and as a result, the temperature distribution of the maximum sheet passing area is heated so as to be symmetrical. As a result, warm-up in which a well-balanced and substantially uniform heating is performed within the maximum sheet passing area is possible.

[0018]

1 and 2 show a main part of a fixing device according to an embodiment of the present invention. FIG. 1a is a schematic front view, FIG. 1b is a schematic side view, and FIG. 2 is an explanatory diagram showing the configuration of the temperature control system.

As shown in FIGS. 1 and 2, this fixing device is provided with a cylindrical heating roll 10 which is arranged to be driven to rotate in the direction of arrow A, and is arranged inside the cylinder of the heating roll 10. Two heaters 20 and 3 for heating the roll
0, drivers 25 and 35 for controlling the energizing operation of the heaters 20 and 30 from a power supply unit (not shown), and two drivers which are disposed in contact with the surface of the heating roll 10 and detect the surface temperature thereof. Based on the temperature sensors 40, 50 and the temperature information detected by the temperature sensors 40, 50, the operation of energizing the two heaters 20, 30 (strictly speaking, the driver 2
5 and 35), and a pressure roll 70 as a pressure member that is arranged to rotate while being pressed against the heating roll 10 and presses the recording paper P against the heating roll 10. The main part is configured.

In FIG. 1A, T denotes a toner image formed on the image forming unit of an image forming apparatus (not shown) in accordance with image information and then transferred to the recording sheet P, and a dashed line indicates a transport path (state) of the recording sheet P. Is shown. In FIG. 1B, reference numeral _WMAX denotes a maximum sheet passing area, which is an area through which the recording sheet P having the maximum width comes into contact with the heating roll 10, and W1 denotes one of two divisions of the maximum sheet passing area _WMAX. sheet passing area (first divided sheet passing area), W2 is other divided sheet passing area when the 2 dividing the maximum paper feed area W _MAX (second
).

The heating roll 10 is basically a cylindrical metal roll made of a metal material such as aluminum or iron, and has a structure in which an elastic release layer is laminated on the roll surface as required. It has become. The pressure roll 70 is also formed in a cylindrical shape with a metal material such as stainless steel, and has a structure in which a release layer and the like are laminated on the roll surface as needed. In this fixing device, a belt-shaped pressing member or a pad-shaped pressing member may be used instead of the pressing roll 70.

The heater 20 of the above two heaters is
A main heater energization heating type that mainly heats the first divided sheet passing area W1 in the heating roll 10 to a required temperature M _1, the heat generating portion is formed by winding appropriate heating wire into a coil shape Of structure. On the other hand, the heater 30
Is an electric heating type sub-heater that mainly heats the second divided sheet passing area W2 in the heating roll 10 until a required temperature M ₂ (normally, M ₁ = M ₂ ). Is appropriately wound in a coil shape to form a heat generating portion.

Each of the two heaters 20 and 30 is configured to simultaneously heat the sheet passing areas of the other party to some extent at the same time. That is, the main heater 20, which can be heated until the second divided sheet passage region W2 at the same time heating the first divided sheet passing area W1 lower temperature M ₃ than the required temperature M _1, The heating wire is also wound at a position facing the second divided sheet passing area W2 under the condition that the number of windings, the winding interval, and the like are different. Further, the sub heater 30 is connected to the second divided sheet passing area W.
Are those when heating the 2 first divided sheet passing area W1 can be simultaneously heated to a lower temperature M ₄ than the required temperature M _2, even electrodeposition at a site facing the second divided sheet passing area W2 The structure is such that the heat wire is wound under the condition that the number of windings, the winding interval and the like are different.

FIGS. 3A and 3B show the heating characteristics (heat distribution) of the two heaters 20 and 30. FIG. 3A shows the main heater 20 and FIG. 3B shows the sub heater 30. It is. FIG. 4 shows two heaters 20, 3
It shows a relationship in which a heating characteristic of 0 is set. 3 and 4, the positions on the heaters are indicated by the distances from the center position of each heater. Further, the heat generation ratio in FIG. 3 indicates the ratio of the heat generation amount at each part when the maximum heat generation amount of each heater is set to 100 (%). The heat generation ratio shown in FIG. 4 is a ratio of the heat generation amount at each portion of each heater when the total heat generation amount obtained at the center of the heater when both heaters are heated at the same time is 100 (%). This figure shows a ratio obtained by adding the heat generation ratios at the respective portions of the heater. Incidentally, the heater 20 and 30, in the fixing device employing the end criterion (the side registration) as conveyance reference of the recording sheet P (image forming apparatus), the width of the maximum paper feed area W _MAX is approximately 297 mm, the first divided The width of the paper passing area W1 is about 210 m
m, for heating the heating roll 10 in which the width of the second divided sheet passing area W2 is set to about 87 mm.

As is clear from FIGS. 3 and 4, the main heater 20 is set so as to mainly heat the first paper passage area W1 and also to some extent the second paper passage area W2. , The sub-heater 30 is located in the second sheet passing area W2.
The first sheet passing area W1, which mainly heats the first sheet passing area W1, is set to be heated to some extent. In addition, the heat generation ratio of the corresponding portion of each heater that heats the region that is the boundary between the two divided paper passing areas W1 and W2 gradually decreases as it goes in the direction into the divided paper passing area heated by the other heater. In addition, the characteristics are such that they intersect each other on the way, and the sum of the heat generation ratios of the corresponding portions of both heaters is adjusted to be substantially the same level as the sum of the heat generation ratios at the center of each heater.

Each of the two temperature sensors 40 and 50 is disposed so as to come into contact with a non-sheet passing area of the heating roll 10 through which the recording paper P does not pass. The temperature sensor 50 is installed in the first non-sheet passing area F1 adjacent to the first divided sheet passing area W1, and the temperature sensor 50 is installed in the second non-sheet passing area F2 adjacent to the second sheet passing area W2. The temperature sensors 40 and 50 may be provided at positions as close as possible to the divided sheet passing areas W1 and W2 among the non-sheet passing areas F1 and F2. In addition, for each of the non-sheet passing areas F1 and F2 where the temperature sensors 40 and 50 are installed, each divided sheet passing area W
Heating portions (winding of heating wires) of the heaters 20 and 30 are formed so as to be extended so that they can be heated to the same level as 1 and W2.

The control device 60 is constituted by a microcomputer or the like, and has two temperature sensors 40,
The temperature information output from the image forming apparatus 50 is input, and an information signal S (power ON-OFF signal,
Start and end signals of image forming operation, recording paper P to be used
Of the heaters 20 and 30 after predetermined information processing relating to temperature control is performed based on these input signals and the like.
A control signal for controlling the energizing operation of the driver 25, 35
Is output to In practice, the heater 20
Is performed based on the detection information of the temperature sensor 40, and the control regarding the power supply of the heater 30 is performed based on the detection information of the temperature sensor 50.

Next, the operation of the fixing device will be described.

First, when a signal for starting the fixing operation is input from the main body of the image forming apparatus, the heating roll 10 is heated by predetermined heaters 20 and 30 to predetermined temperatures (M ₁ , M ₂ ) and rotated. Start driving. When the heating roll 10 is heated to the predetermined temperature, the toner image T to be fixed is placed between the heating roll 10 and the pressure roll 70.
Is transferred to the recording paper P onto which the image data has been transferred. The toner image T is heated and fixed by passing the recording paper P while being pressed against the heating roll 10. Thereafter, the recording paper P is discharged from between the heating roll 10 and the pressure roll 70. Completes the fixing. When continuous fixing is performed, the above steps are repeated.

In this fixing device, the main heater 20 mainly controls the power supply based on the detection information of the temperature sensor 40 installed on the side of the non-sheet passing area F1 adjacent to the first divided sheet passing area W1 to be heated. On the other hand, since the sub-heater 30 is energized and controlled based on the detection information of the temperature sensor 50 installed on the side of the non-sheet passing area F2 adjacent to the second divided sheet passing area W2 mainly heated, Independent control is performed based on the temperature information in the area adjacent to the area to be heated by itself, and accurate control is performed. That is, by controlling the energization of the heaters 20 and 30 in this manner, the first divided sheet passing area W1 and the second divided sheet passing area W2 of the heating roll 10 are heated to a required temperature and the temperature is increased. It is almost maintained at the temperature. Thereby, since the heating roll 10 is accurately heated to a desired temperature in each paper passing area,
Good fixing can be performed at a desired temperature.

Since both the temperature sensors 40 and 50 are disposed in the non-sheet passing areas F1 and F2 of the heating roll 10,
The paper passing area (W _MAX ) of the heating roll 10 is not damaged by the contact of the temperature sensor temperature, so that it is possible to prevent the image quality from being deteriorated due to the scratch. Further, the rate at which the sensor detection surface is contaminated by the adhesion of toner, paper powder, or the like is reduced, so that the surface temperature of the heating roll 10 can be accurately detected. Temperature control becomes possible, and good fixing can be stably performed.

Further, even if the recording paper P is wrapped around (the paper passing area of) the heating roll 10, there is no hindrance to the detection of the surface temperature by the temperature sensor, and the original temperature of the roll surface is normally detected. This makes it possible to quickly stop the heating of the heating roll 10 (by the heater) when a wrapped paper jam occurs,
As a result, (excessive) heating operation of the heating roll based on abnormal temperature detection at the time of occurrence of wrapped paper jam can be avoided, and safety can be improved.

Even when heating is performed by only one heater 20, the divided sheet passing area W2 to be heated by the other heater 30 is preliminarily heated to a relatively low temperature. The first divided paper passing area W1 and the second divided paper passing area W2 are used immediately after the fixing to the recording paper P of a small size that can be fixed in the first divided paper passing area W1 is continued. Even when the fixing is performed on the large-sized recording paper P, the second divided paper-passing area W2 by the heater 30 is equivalent to the preliminary heating of the second divided paper-passing area W2. Can be relatively quickly heated to a desired temperature. As a result, the temperature difference in the maximum sheet passing area is relatively small, and the occurrence of defective fixing and the occurrence of wrinkles on the recording paper are reduced.

Further, in this fixing device, when simultaneous heating is performed by the two heaters 20 and 30, as shown in FIG. 5, the distribution of the surface temperature in the maximum paper passing area _WMAX of the heating roll 10 is almost equal. Since the heating is performed symmetrically, the fixing operation can be started immediately after the warm-up is completed. Moreover, at the time of warm-up due to simultaneous heating by the two heaters 20 and 30, it is possible to heat the roll surface temperature so that the height difference between the roll surface temperatures falls within 50 ° C. as shown in FIG. This is advantageous because a good fixing operation can be started immediately.

In the fixing device described above, the two heaters 20 and 30 are of a type capable of preliminarily heating the divided sheet passing area of the other party to some extent (see FIGS. 3 and 4). 6), as illustrated in FIG. 6, a heater 20 of a type that does not preliminarily heat the divided sheet passing area on the other side.
30 may be used.

[0036]

As described above, according to the present invention,
The following effects can be obtained at the same time.

Even in a fixing device of a type in which a heating rotator is heated by two heaters, the two heaters are accurately controlled to perform stable fixing, and a temperature detector in a paper passing area of the heating rotator. To prevent the occurrence of scratches due to contact with the image, to prevent the deterioration of image quality, to prevent contamination due to adhesion of toner and the like to the temperature detector, to maintain accurate control of the heater, and to perform stable fixing, Accurate temperature detection is possible even when the recording paper is wrapped around, and the heating of the heater can be stopped quickly.Fusing to large-sized recording paper is performed immediately after continuous fixing to small-sized recording paper is performed. However, there is no occurrence of fixing failure or paper wrinkles due to the temperature difference, and further, there is no reduction in the life of the heating rotator.

[Brief description of the drawings]

1A and 1B show a main part of a fixing device according to an embodiment of the present invention, wherein FIG. 1A is a schematic front view thereof, and FIG.

FIG. 2 is an explanatory diagram illustrating a configuration of a temperature control system of the fixing device.

3A and 3B show heating characteristics of two heaters (a relationship between a heater position and a heat generation ratio), wherein FIG. 3A is a diagram showing heating characteristics of a main heater, and FIG. 3B is a diagram showing heating characteristics of a sub-heater.

FIG. 4 is a diagram showing a state in which the heating characteristics (relation between the heater position and the heat generation ratio) of two heaters are set.

FIG. 5 is a graph showing the results of measuring the surface temperature of a heating roll when heating is performed simultaneously by two heaters.

FIG. 6 is a diagram showing another example in which the heating characteristics of two heaters are distributed and set.

FIG. 7 is an explanatory diagram showing a configuration of a temperature control system in a conventional fixing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Heating roll (heating rotary body), 20 ... Main heater (1st heater), 25 ... Driver (part of 1st control means), 30 ... Sub heater (2nd heater), 35
... driver (part of the second control means), 40 ... temperature sensor (first temperature detector), 50 ... temperature sensor (second temperature detector), 60 ... control device (first and second) P: recording paper, T: toner image (unfixed image), W
_MAX : maximum paper passing area, W1: first paper passing area, W2: second paper passing area, F1, F2: non-paper passing area.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Nagakazu Okegawa 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Seiichi Akikawa 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Shuichi Suzuki 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Shuji Yuga 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Haruhiko Nishida 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Kazumi Inaba 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Masayuki Kawano 2274 Hongo, Ebina City, Kanagawa Prefecture Address, F-term in Fuji Xerox Co., Ltd. (reference) 2H033 AA03 AA18 BA25 B A27 BA31 BA32 BB18 BB21 BB28 CA07 CA28 CA30 CA32 CA48 3K058 AA42 AA86 BA18 CA23 CA92 DA02 GA06

Claims (3)

[Claims] 1. A heating rotator for heating an unfixed image carried on a recording sheet passing therethrough, and a maximum rotator which is an area through which a recording sheet having a maximum width contacts and passes. Of the two divided paper passing areas obtained by dividing the paper area into two, a first heater of an electric heating type for heating one of the divided paper passing areas to a required surface temperature and the other divided paper passing area as required A second heater of an electric heating type for heating to a surface temperature; and two non-sheet passing areas which are areas adjacent to both ends of both ends of the maximum sheet passing area of the heating rotator and through which recording paper does not pass. A first temperature detector that contacts a non-sheet passing area adjacent to the one divided sheet passing area and detects a surface temperature thereof; and a non-sheet passing area adjacent to the other divided sheet passing area. A second temperature detector for detecting the surface temperature by contact with the first temperature detector; First control means for controlling an energizing operation to the first heater based on the output temperature information; and energizing the second heater based on temperature information detected by the second temperature detector. And a second control unit for controlling an operation. 2. The fixing device according to claim 1, wherein the first heater heats the one divided sheet passing area and at the same time lowers the other divided sheet passing area below the required surface temperature. Temperature, and the second heater heats the other divided sheet passing area and also heats the one divided sheet passing area to a temperature lower than the required surface temperature at the same time. Fixing device configured as described above. 3. The fixing device according to claim 2, wherein the heating characteristics of the first heater and the heating characteristics of the second heater are such that heating by the first heater and the second heater is performed simultaneously. In this case, the fixing devices are distributed and set so that the distribution of the surface temperature in the maximum sheet passing area of the heating rotator is substantially symmetrical.