JP2000056598A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an uneven temperature distribution on a fixing roller along the direction of its axis while preventing the rise in temperature of an induction coil. SOLUTION: An induction coil 3 is placed inside the core 2 of a fixing roller 1. A cooling fan 4 is provided near one end of the fixing roller to admit air in the direction of the arrow F. Since the induction coil 3 is higher in winding density and heating value the closer it is to the cooling fan 4, it can compensate for the uneven cooling of the core 2 such that the core 2 is cooled more near the fan. Therefore, the coil can be cooled as an uneven temperature distribution in the direction of the axis of the roller is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device having an induction heating type fixing roller (heating roller).

[0002]

2. Description of the Related Art As a fixing device used in an image forming apparatus such as a copying machine, a printer, and a facsimile, a fixing device having an induction heating type fixing roller is well known. In general,
In the induction heating method, an induction coil is provided inside a fixing roller, and an alternating current (high-frequency current) is supplied to the induction coil to generate an induction magnetic flux, and the induction magnetic flux generates an induction current in a conductive layer on the outer periphery of the roller. Then, the fixing roller is caused to generate heat by Joule heat accompanying the induced current.

[0003]

However, since the induction coil is provided inside the fixing roller, the temperature of the coil rises due to radiant heat from the heated roller core and self-heating of the coil. There is a problem that the temperature may exceed the heat-resistant temperature of the insulating coating and the device may be damaged.

[0004] As a countermeasure against the coil temperature rise, there are known countermeasures such as using a high-cost heat-resistant coil and further cooling the coil using a fan. FIG. 33 shows an example of a fixing device provided with a cooling fan for the fixing roller. A cooling fan 14 is arranged near one end of the fixing roller 11, and air is blown in the direction of arrow F to form a roller core. The induction coil 13 disposed inside the cooling device 12 is cooled.

[0005] However, in such a countermeasure method, the temperature decreases in a location closer to the cooling fan, and the temperature is shifted in the axial direction of the fixing roller (a temperature distribution occurs), and satisfactory fixing performance cannot be obtained. There is. In the example shown in FIG. 33, as can be seen from the graph showing the roller surface temperature at the axial position of the fixing roller, the temperature is lower at the roller end near the cooling fan 14, and the roller surface is closer to the opposite end. Temperature is rising.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-described problem in a fixing device having a conventional induction heating type fixing roller, and to prevent the temperature of the induction coil from rising and to prevent the temperature from shifting in the fixing roller axial direction. And

[0007]

According to the present invention, there is provided a fixing device having an induction heating type fixing roller and a cooling fan for cooling an induction coil inside the fixing roller according to the present invention. This is solved by increasing the winding density of the induction coil as the distance is closer.

According to another aspect of the present invention, the induction coil has the highest winding density at the center of the fixing roller in the axial direction, and the cooling fan is provided at the center of the fixing roller in the axial direction. Suggest.

Further, in order to solve the above-mentioned problems, the present invention provides a fixing device having an induction heating type fixing roller and having a cooling fan for cooling an induction coil inside the fixing roller. It is proposed to provide a regulating member for regulating the area.

Further, in order to solve the above-mentioned problems, the present invention proposes that the regulating member is a guide member for guiding wind from the cooling fan. Furthermore, in order to solve the above-mentioned problem, the present invention proposes that the regulating member is a tubular member having a hole provided in a peripheral wall.

Furthermore, in order to solve the above-mentioned problems, the present invention proposes that the tubular member is partially or entirely closed at one axial end. Furthermore, in order to solve the above-mentioned problem, the present invention proposes that the inner diameter of the tubular member gradually increases from one end to the other end.

Further, in order to solve the above-mentioned problem, the present invention provides a fixing device including an induction heating type fixing roller and a cooling fan for cooling an induction coil inside the fixing roller. It is proposed that a plurality of blowing fans for blowing air into the fixing roller and a plurality of suction fans for sucking hot air from the fixing roller are provided.

Further, in order to solve the above-mentioned problems, the present invention proposes that the suction fan is made of a heat-resistant member. Furthermore, in order to solve the above-mentioned problem, the present invention proposes that the air volume of the suction fan is larger than the air volume of the blow fan.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. In order to mainly describe the portion according to the present invention, the configuration of the fixing roller and the cooling fan will be mainly described, and other portions, such as a pressure roller, a pressure mechanism, an oil application mechanism, and a main body case will be described. Will not be described.

FIG. 1 is a sectional view showing a schematic configuration near a fixing roller in a fixing device according to an embodiment of the present invention.
In this figure, an induction coil 3 is disposed inside a core 2 of a fixing roller 1. A cooling fan 4 is disposed near one end of the fixing roller 1 to cool the induction coil 3 by blowing air in the direction of arrow F. The induction coil 3 can be made coreless by a method such as solidifying the coil with an appropriate adhesive. In addition, by using a material having high rigidity, it is possible to make the coreless. Alternatively, it may be wound around the bobbin 5 as in the example shown in FIG.

In the present embodiment, the winding of the induction coil 3 is not uniform, and the closer to the fan 4 the higher the winding density (the larger the number of turns per unit length), and the denser the fan 4 is. It is wound so that it becomes sparse as you move away from it. For this reason, when the induction coil 3 is energized,
In the dense portion of the coil, that is, in the portion (A), the magnetic flux generated from the induction coil 3 changes largely and the eddy current generated also increases, so that the calorific value of the metal core 2 increases. On the other hand, as the coil approaches the end on the opposite side of the roller 1, the winding becomes less sparse, so that the eddy current generated decreases, and the heat generation amount decreases in the portion (B).

FIG. 3 shows an induction coil 3 according to this embodiment.
FIG. 3 is a schematic diagram showing a comparison between a winding density of the coil and a calorific value at an axial position. As shown in this figure, the amount of heat generation is larger on the (A) side closer to the cooling fan 4, and is smaller as it approaches the (B) side.

At this time, in the present embodiment, the wind is sent from the cooling fan 4 arranged near the part (A), so that the induction coil 3 and the core metal 2 are strong on the (A) side, and (B)
The side will be cooled slightly. Therefore, the temperature distribution of the cored bar 2 is averaged, and is maintained at a substantially constant temperature in the axial direction. In addition, the induction coil 3 is also strongly cooled in the portion (A) that receives a large amount of radiant heat from the cored bar 2.
Excessive rise in coil temperature in the portion (A) can be prevented.

In this embodiment, a cooling fan 4 is provided on the left side of the fixing roller 1 in FIGS. 1 and 2, and the number of turns (winding density) of the induction coil 3 per unit length is reduced from left to right. However, the direction and degree of change in the position and number of cooling fans or the winding density of the induction coil are not limited to this, and may be changed according to various conditions such as the size and temperature of the fixing roller. It is possible to

Next, a second embodiment of the present invention will be described. In FIG. 4, an induction coil 23 is provided inside a core metal 22 of the fixing roller 21. A cooling fan 24 is arranged inside the cored bar 22 and inside the induction coil 23 at the center in the roller axial direction.
Naturally, the diameter of the cooling fan 24 is set such that the cooling fan 24 does not come into contact with the induction coil 23 even when the cooling fan 24 rotates.

As shown in FIG. 5, the winding density of the induction coil 23 of the present embodiment is increased at the center in the roller axis direction, and is reduced as approaching the roller end. The cooling fan 24 sends air in the direction of arrow F. Since the winding density of the coil is high at the center of the roller, the temperature rise at the center of the roller is large without a cooling fan, and the insulation of the induction coil may be damaged depending on the type of coil and the gap with the roller core. There is. Therefore, in the present embodiment, the cooling fan 24 is disposed at the center of the roller.

The fixing device according to the present embodiment corresponds to an image forming apparatus in which the paper conveyance reference is the center reference, and the number of turns of the induction coil 23 is increased at the center to reduce heat generation at the center of the fixing roller 21. It is a big one. In this case, the amount of heat generated by the coil increases at the center of the roller. However, in the present embodiment, the cooling fan 24 is provided at the center in the roller axis direction.
Can be prevented from being damaged.

The rotation direction of the cooling fan 24, that is, the wind direction may be reversed. Further, in order to enhance the cooling effect, a plurality of fans can be arranged inside the core metal (inside the coil 23).

FIG. 6 shows another example of this embodiment.
2 shows an exploded view of a section of a fixing roller, an induction coil and a cooling fan. The fixing roller 21-2 shown in this figure has two induction coils 23 inside the roller. The coil 23 is a central coil for generating heat at the center of the roller, and the coil 23 is an end coil for generating heat at both ends of the roller. A central connecting portion 23c connecting the coil portions 23a and 23b on both sides of the coil 23 is
The cooling fan 24 is disposed at a position that does not contact the cooling fan 24. For example, in the roller cross-sectional view of FIG. 6, the connecting portion 23c of the coil 23 is illustrated in the center of the fan 24,
This is disposed on the back side so as not to contact the fan 24.

In the fixing roller 21-2 shown in FIG. 6, when the size of the sheet (the width in the longitudinal direction of the roller) is large, both the central coil 23 and the end coil 23 are energized to form the entire roller (full width). Can generate heat. on the other hand,
When the size of the paper (the width in the longitudinal direction of the roller) is small, only the central coil 23 is energized to generate heat in the central portion of the roller. In this way, the heat generation state of the fixing roller can be changed according to the paper size.

Next, a third embodiment of the present invention will be described. In FIG. 7, an induction coil 33 is provided inside a core metal 32 of the fixing roller 31. In the present embodiment, the winding density of the induction coil 33 is constant, and the core metal 32 uniformly generates heat. In addition, a cooling fan 34 is arranged near one end of the fixing roller 31. Then, so as to cover the cooling fan 34 and the induction coil 33 halfway,
Cylindrical guide member 35 fitted inside cored bar 32
Is provided. The length of the guide member 35, which is a regulating member that regulates the region through which the cooling air passes, is shorter than the core metal 32,
One end of the guide member 35 is located substantially at the center of the metal core 32. The cooling fan 34 disposed in the guide member 35 blows air in the direction of arrow F to cool the induction coil 33.

In the present embodiment, since the wind coming out of the cooling fan 34 is guided by the guide member 35 and hits the induction coil 33, the wind does not directly hit the core metal 32 at the end of the fixing roller. The temperature at the end of 32 is not lost. For this reason, the temperature distribution in the roller axis direction of the cored bar 32 is not biased.

In order to generate an eddy current in the metal core 32 by causing the induced magnetic flux generated by the coil 33 to act on the metal core 32 (to generate heat in the metal core 32), the guide member 35 is made of a non-magnetic material. It is preferably formed of a body, for example, a resin.

Incidentally, in the example shown in FIG.
The length of the guide member 35 is such that the inner end of the roller is positioned substantially at the center of the core bar 32. However, as shown in FIG. The length of the guide member 35a may be set so as to reach the end. Of course, the length of the guide member can be determined to a length other than those illustrated in FIGS. 7 and 8.

Next, a fourth embodiment of the present invention will be described. In FIG. 9, an induction coil 43 is provided inside a cored bar 42 of the fixing roller 41. Induction coil 43
Is constant, and the core metal 42 is uniformly heated. Further, a cooling fan 44 is disposed near one end of the fixing roller 41. And the induction coil 43
The air guide tube 45 is provided inside. As shown in FIG. 10, a large number of holes 46 are formed in the wall surface of the air guide tube 45, which is a regulating member that regulates a region through which the cooling air passes. Both ends of the air guide tube 45 are open as can be seen from the sectional view of the air guide tube 45 shown in FIG.

When the power is turned on, an eddy current is generated in the metal core 42 due to a change in magnetic flux generated from the induction coil 43,
The roller generates heat due to Joule heat. At this time, the cooling fan 44 rotates to blow air into the air guide tube 45 in the direction of arrow F. Since a large number of holes 46 are provided in the air guide tube 45 as described above, the wind from the fan 44
And is blown out from the hole 46 and hits the induction coil 43 to cool the coil. In this embodiment, the coil 43 is cooled by the wind blown out from the hole 46 of the air guide tube 45, but since the wind of the fan 44 does not strongly hit the core 42 at the roller end, the core 42 is moved in the axial direction. Does not cause uneven cooling.

In the air guide tube 45 shown in FIG.
6 are uniformly distributed throughout, but the distribution of holes in the air guide tube is not particularly limited, and is uniformly (uniformly) in the axial direction.
It may be provided, or the distribution density may be changed. Also,
The size and direction of the holes may be constant or may be varied.

For example, in the air guide tube 45a shown in FIG.
The number of holes 46 is small on the side close to the cooling fan 44 (the distribution density is low). The closer to the cooling fan, the stronger the force of the wind blown out from the hole 46 and the greater the cooling. However, the configuration of the air guide tube 45a in FIG. 12 allows the entire induction coil to be uniformly cooled. Air guide tube 45
FIG. 13 shows a cross section of FIG.

FIG. 14 is a sectional view showing another example of the fixing roller of the present embodiment. Fixing roller 41-2 shown in FIG.
, One end of the air guide tube 45, that is, the end opposite to the cooling fan 44 is closed. FIG. 15 shows a cross section of the air guide tube 45, and FIG. 16 shows a perspective view thereof. By closing the end of the air guide tube on the side opposite to the cooling air blowing side, the amount of air blown out from the holes 46 provided on the peripheral wall of the air guide tube is increased, and the cooling effect is enhanced.

An air guide tube having a structure as shown in FIG. 17 may be used. In this air guide tube 45a,
While closing the end of the air guide tube on the side opposite to the cooling air blowing side, the number of holes 46 is small (low distribution density) on the blowing side, and the number of holes 46 increases as the distance from the fan increases. I try to blow out a lot. FIG. 18 shows a cross section of the air guide tube 45a.

As shown in FIG. 19, a small opening 47 may be provided at the end of the air guide tube opposite to the side where the cooling air is blown. In the example of FIG. 19 as well, the amount of wind blown out from the hole provided in the peripheral wall can be increased more than the air guide tube 45 of FIG.

Incidentally, the fixing roller 41- shown in FIG.
FIG. 20 shows a cross section of No. 2 (a cross section in a direction orthogonal to the roller axis). As shown in FIG. 20, the induction coil 43 is
Apart from 5, the air duct 45 has no role as a bobbin for winding the coil. In this case, the induction coil 43 may be hardened with an adhesive or the like, or a coil having high rigidity may be used. On the other hand, a fixing roller 41-3 shown in FIGS. In the fixing roller 41-3, the induction coil 43 is wound around the air guide tube 45, and the air guide tube 45 also functions as a bobbin.

Next, a fifth embodiment of the present invention will be described. This embodiment is the same as the fourth embodiment except that the winding of the induction coil is different from the configuration of the air guide tube provided inside the induction coil. Here, the fourth
The points different from the above embodiment will be described.

As shown in FIG. 23, the induction coil 53 of this embodiment is wound with a high winding density at both ends of the roller and a low winding density at the center. Therefore, the calorific value of the core metal is large at both ends and small at the center. Correspondingly, as shown in FIG. 24, the air guide tube 55 provided inside the induction coil 53 (FIG. 23) has holes 5 at both ends.
The diameter of 6a is larger than the diameter of the hole 56b at the center. For this reason, at both ends of the roller that generates a large amount of heat,
More wind blows out from the hole 56a, and the cooling effect is improved at both ends as compared with the central portion, so that the whole can be uniformly cooled. FIG. 25 shows a cross section of the air guide tube 55.

As shown in FIG. 26, the end opposite to the blowing side may be closed. In the case of this configuration, the amount of air blown out from the holes 56a and 56b provided on the peripheral wall of the air guide tube is increased as compared with the air guide tube 55 having both open ends.
The cooling effect can be enhanced. FIG. 27 shows a perspective view of the air guide tube 55.

Next, a sixth embodiment of the present invention will be described. In FIG. 28, an induction coil 63 is provided inside a core metal 62 of a fixing roller 61. Induction coil 6
The winding density of No. 3 is constant, and the core metal 62 uniformly generates heat. In addition, a cooling fan 64 is disposed near one end of the fixing roller 61. And the induction coil 63
The air guide tube 65 is provided inside the. A large number of holes 66 are formed in the wall surface of the air guide tube 65 which is a regulating member that regulates a region through which the cooling air passes.

The inside of the air guide tube 65 is provided in a tapered shape, and has a maximum thickness at a position close to the fan 64 and gradually decreases as the distance from the fan increases.
For this reason, the inside diameter of the air guide tube 65 is small at the end on the fan 64 side and is maximum at the opposite end. In addition, the air guide tube 65
The hole 66 provided in the hole is configured such that the hole diameter is smaller as the position is closer to the fan 64 and becomes larger as the position is farther from the fan.

When the power is turned on, an eddy current is generated in the cored bar 62 due to a change in magnetic flux generated from the induction coil 63,
The roller generates heat due to Joule heat. At this time, the cooling fan 64 rotates to blow air into the air guide tube 65 in the direction of arrow F. Since a large number of holes 66 are provided in the air guide tube 65 as described above, the wind from the fan 64
From the hole 66 and hits the induction coil 63 to cool the coil. In the present embodiment, although the coil 63 is cooled by the wind blown out from the hole 66 of the air guide tube 65, the wind of the fan 64 does not strongly hit the core metal 62 at the roller end. Does not cause uneven cooling.

Further, since the inside of the air guide tube 65 is tapered, the air can easily pass through as compared with the case where there is no taper, and the cooling efficiency can be increased. And the air guide pipe 6
The hole 66 provided in the hole 5 has a smaller hole diameter as it is closer to the fan 64 and a larger hole diameter as it is farther from the fan. Is not biased.

The distribution of the holes 66 provided in the air guide tube 65 is not particularly limited, and may be provided constant in the axial direction or may be changed. Also, the size of the holes may be the same or the direction may be changed. For example, in the example shown in FIG. 29, the hole 66a provided in the air guide tube 65a is
The hole diameters are all the same, but the orientation is changed.
That is, on the left side of the figure close to the fan, the direction of the hole is provided at a right angle or close to the center axis, and the angle with respect to the center axis is set small so as to approach the direction of the wind toward the right side of the figure. I have. In the example of FIG. 29,
The wind becomes easier to pass through the hole 66a as the distance from the cooling fan increases, so that the cooling efficiency at a position far from the fan can be increased and the whole can be uniformly cooled.

Next, a seventh embodiment of the present invention will be described. In FIG. 30, an induction coil 73 is disposed inside a core metal 72 of a fixing roller 71. Induction coil 73
Is constant, and causes the core metal 72 to generate heat uniformly. Cooling fans 74a and 74b are arranged near both ends of the fixing roller 71, respectively. The cooling fan 74a is a blowing fan that blows air into the metal core 72, and the cooling fan 74b is a suction fan that draws hot air from the metal core 72.

In the present embodiment, since the air is blown from one side of the fixing roller 71 and is sucked out on the opposite side, the induction coil 73 can be cooled without generating a temperature gradient in the roller axis direction with respect to the roller core. Can be.

The numbers of the blowing fans and the suction fans are not limited to those in the present embodiment. For example, in order to obtain a more powerful cooling effect, a plurality of the blowing fans and the suction fans are provided. Is also good. Alternatively, one of them may be singular and the other fan alone may be provided in plural. Furthermore, in the example of FIG. 30, the blower fan is provided on the left side and the suction fan is provided on the right side, but the arrangement values of both can be reversed.

As a cooling fan, a resin fan is inexpensive. However, when two fans, a blowing fan 74a and a suction fan 74b, are provided as in the embodiment of FIG. The wind heated to a high temperature by the heat from the induction coil contacts the suction fan 74b. Therefore, in some cases, the suction fan 74b may be damaged.

Therefore, in the configuration in which the blowing fan and the suction fan are provided on both sides of the fixing roller, the suction fan is made of a heat-resistant material, and the flow rate of the suction fan is made smaller than the flow rate of the blow fan. Increasing is proposed as eighth and ninth embodiments of the invention, respectively.

FIG. 31 shows an eighth embodiment of the present invention, in which a blower fan 84a is provided on one side of a fixing roller 81, and a suction fan 84b is provided on the opposite side. In the present embodiment, the suction fan 84b (the structure and blades of the fan) is made of a heat-resistant resin (for example, engineering plastic). Therefore, the blowing fan 84
Even if the wind blown from a and heated by the heat from the core metal 82 and the induction coil 83 comes into contact with the suction fan 84b, the suction fan 84b is not damaged, and the cooling of the induction coil 83 is ensured. It can be carried out.

The arrangement and number of the blowing fans and the suction fans can be changed as appropriate. Further, a metal can be used as the heat-resistant material of the suction fan 84b, and the suction fan 84b may be a metal fan.

FIG. 32 shows a ninth embodiment of the present invention, in which a blower fan 94a is provided on one side of a fixing roller 91 and a suction fan 94b is provided on the other side. In this embodiment, the air volume of the suction fan 94b is set to be larger than the air volume of the blow fan 94a. Therefore, the air inside the cored bar 92 can be efficiently sucked out, the ventilation inside the roller can be ensured, and the induction coil 93 can be reliably cooled. In addition, the arrangement and number of the blowing fan and the suction fan can be appropriately changed.

[0054]

As described above, according to the fixing device of the present invention, the winding density of the induction coil is increased as the position is closer to the cooling fan and the heat generation is increased at a position closer to the fan. The induction coil can be cooled while keeping the axial temperature distribution constant.

According to the second aspect of the present invention, the induction coil can be cooled while maintaining a constant temperature distribution in the axial direction of the fixing roller even in the central reference device. According to the third aspect of the present invention, since the regulating member for regulating the ventilation area of the cooling fan is provided, the induction coil can be cooled while keeping the temperature distribution in the fixing roller axial direction constant.

According to the fourth aspect of the present invention, by guiding the air from the cooling fan, local cooling of the fixing roller is prevented, and the induction coil can be cooled while maintaining a constant temperature distribution in the axial direction of the fixing roller. it can.

According to the fifth aspect of the present invention, since the cooling air blows out from the hole of the tubular member, local cooling of the fixing roller is prevented, and the induction coil is cooled while keeping the temperature distribution in the fixing roller axial direction constant. Can be.

According to the sixth aspect of the present invention, since one end in the axial direction of the tubular member is partially or entirely closed, the wind blown out from the hole in the peripheral wall of the tubular member becomes strong, and the cooling effect can be enhanced. it can.

According to the configuration of claim 7, the inner diameter of the tubular member gradually increases from one end to the other end, so that the cooling air can easily pass through as compared with the case where the inner diameter is constant.
Cooling efficiency can be increased.

According to the eighth aspect of the present invention, since the blowing fan and the suction fan are provided, the air volume can be secured even at a position distant from the blowing fan, and uniform cooling over the entire area in the axial direction of the fixing roller. This makes it possible to efficiently cool the induction coil and keep the temperature distribution in the fixing roller axial direction constant.

According to the ninth aspect of the present invention, since the suction fan is made of a heat-resistant member, it does not break even when the high-temperature wind comes into contact with the suction fan, and the cooling of the induction coil is ensured. It can be carried out.

According to the tenth aspect, since the air volume of the suction fan is larger than the air volume of the blow fan, the hot air inside the roller can be efficiently sucked and the induction coil can be reliably cooled.

[Brief description of the drawings]

FIG. 1 is a cross-sectional configuration diagram illustrating a main part of a fixing device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of another example of a fixing roller in which an induction coil is wound around a bobbin.

FIG. 3 is a schematic diagram showing a comparison between a winding density of an induction coil and a heat generation amount at a position in an axial direction in the present embodiment.

FIG. 4 is a cross-sectional configuration diagram illustrating a main part of a fixing device according to a second embodiment of the present invention.

FIG. 5 is a schematic diagram illustrating a positional relationship between a winding density of an induction coil and a cooling fan according to the embodiment.

FIG. 6 is a sectional view and an exploded view of a fixing roller showing another example of the embodiment.

FIG. 7 is a cross-sectional configuration diagram illustrating a main part of a fixing device according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional configuration diagram illustrating another example of a guide member in the embodiment.

FIG. 9 is a cross-sectional configuration diagram illustrating a main part of a fixing device according to a fourth embodiment of the present invention.

FIG. 10 is a perspective view showing a configuration of an air guide tube in the fixing device.

FIG. 11 is a sectional view of the air guide tube.

FIG. 12 is a perspective view showing another example of the air guide tube.

FIG. 13 is a sectional view of the air guide tube.

FIG. 14 is a cross-sectional view illustrating a fixing roller according to another example of the embodiment.

FIG. 15 is a sectional view of an air guide tube of the fixing device.

FIG. 16 is a perspective view of the air guide tube.

FIG. 17 is a perspective view showing another example of the air guide tube.

FIG. 18 is a sectional view of the air guide tube.

FIG. 19 is a sectional view showing still another example of the air guide tube.

20 is a sectional view of the fixing roller shown in FIG.

FIG. 21 is a cross-sectional view illustrating a fixing roller according to still another example of the embodiment.

FIG. 22 is a sectional view of the fixing roller.

FIG. 23 is a side view showing a configuration of an induction coil according to a fifth embodiment of the present invention.

FIG. 24 is a perspective view showing a configuration of an air guide tube in the fixing device.

FIG. 25 is a sectional view of the air guide tube.

FIG. 26 is a sectional view showing another example of the air guide tube.

FIG. 27 is a perspective view of the air guide tube.

FIG. 28 is a sectional configuration diagram illustrating a main part of a fixing device according to a sixth embodiment of the present invention.

FIG. 29 is a cross-sectional view showing a configuration of another example of the air guide tube.

FIG. 30 is a sectional configuration diagram illustrating a main part of a fixing device according to a seventh embodiment of the present invention.

FIG. 31 is a sectional configuration diagram showing a main part of a fixing device according to an eighth embodiment of the present invention.

FIG. 32 is a sectional view showing a main part of a fixing device according to a ninth embodiment of the present invention.

FIG. 33 is a schematic diagram comparing the configuration of an example of a conventional fixing device with the roller surface temperature at an axial position.

[Explanation of symbols]

1,11,21,31,41,61,71,81,91
Fixing rollers 2, 12, 22, 32, 42, 62, 72, 82, 92
Roller core metal 3,13,23,33,43 Induction coil 53,63,73,83,93 Induction coil 4,14,24,34,44,64 Cooling fan 35,35a Guide member 45,45a, 55,65 , 65a Blower tube 46, 56, 66 hole 74a, 84a, 94a Blowing fan 74b, 84b, 94b Suction fan

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 6/42 G03G 21/00 534 (72) Inventor Jiro Ouchi Shimei, Shibata-cho, Shibata-gun, Miyagi Prefecture DO3-1 F-term in Tohoku Ricoh Co., Ltd. (Reference) 2H027 ED25 JA11 JB14 JB15 JB16 JB17 JB22 JC08 2H033 AA03 BA29 BE06 3K059 AA10 AB00 AB23 AC33 AD03 AD05 CD48 CD52 CD73 9A001 HZ34 JJ21 JJ35 KK42 LZ02

Claims (10)

[Claims] 1. A fixing device comprising an induction heating type fixing roller and a cooling fan for cooling an induction coil inside the fixing roller, wherein a winding density of the induction coil is higher nearer to the cooling fan. A fixing device. 2. The fixing coil according to claim 1, wherein the induction coil has the highest winding density at a central portion in the fixing roller axial direction, and the cooling fan is provided at a central portion in the fixing roller axial direction. Fixing device. 3. A fixing device having an induction heating type fixing roller and a cooling fan for cooling an induction coil inside the fixing roller, wherein a regulating member for regulating a ventilation area of the cooling fan is provided. Characteristic fixing device. 4. The fixing device according to claim 3, wherein the regulating member is a guide member for guiding wind from the cooling fan. 5. The fixing device according to claim 3, wherein the regulating member is a tubular member having a hole provided in a peripheral wall. 6. The tubular member is characterized in that one end in the axial direction is partially or entirely closed.
The fixing device according to claim 5. 7. The fixing device according to claim 5, wherein the inner diameter of the tubular member gradually increases from one end to the other end. 8. A fixing device including an induction heating type fixing roller and a cooling fan for cooling an induction coil inside the fixing roller, wherein the cooling fan includes a blowing fan for blowing air into the fixing roller. A fixing device comprising a plurality of suction fans for sucking hot air from a fixing roller. 9. The fixing device according to claim 8, wherein the suction fan is formed of a heat-resistant member. 10. The fixing device according to claim 8, wherein the air volume of the suction fan is larger than the air volume of the blow fan.