JPH0572926A - Fixing device - Google Patents

Abstract

PURPOSE:To achieve such stable glossy fixing that the thermal fixing of a toner image does not depend on the quality or the thickness of a transfer material and to obtain the high-quality color toner image having gloss without image stain or wrinkle caused by offset transfer. CONSTITUTION:In a fixing device provided with a heating endless belt 25 wound around a heating roller 11, a peeling roller 21 and a tension roller 22, a pressure endless belt 25B wound around a pressure roller 31, a peeling roller 21A, and a tension roller 22A, and the pressure roller 31 pressing belts toward the heating roller 11 through the superposing part of the belts 25 and 25B, air cooling devices 40 and 50 are provided on both sides of the belts 25 and 25B which extend to the exit from the entrance of the transfer material in the fixing device, and temperature detection sensors 19 and 39 are respectively provided on both rollers 11 and 31. Simultaneously, sensors 25A and 25C are provided on the back side of the endless belt near the roller 21 so as to control the calorific values of the heaters 14 and 34 of the rollers 11 and 31. Then, the glossy color image which is sufficiently melted and soaked into the transfer material is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fixing device for electrophotography, and more particularly to an improvement in a belt type fixing device.

[0002]

2. Description of the Related Art A heat-fixing toner image, especially a fixing device via a belt is disclosed in Japanese Patent Laid-Open No. 49-36342. Is provided via a belt, and the transfer material carrying the toner image is sandwiched between the pressure roller and the belt to be fed and fixed. However, a sufficient nip area N ₁ was not obtained, the supply of heat from the upper heating roller via the belt was not guaranteed, and the toner was not melted to such an extent that the toner image became glossy.

Further, Japanese Patent Application Laid-Open No. 61-122665 also describes a fixing device for performing heat fixing via a belt, but a nip area N ₂ is sufficient due to an independent holding angle of the belt with respect to the pressure roller. Since the length is not long, a sufficient melting time cannot be obtained and heating of the transfer material is insufficient.
In the end, the fixing property depends on the material and thickness of the recording paper (transfer material), resulting in unstable thermal fixing.

Further, in Japanese Unexamined Patent Publication No. 49-70633, two sets of endless belts are suspended between a heat roller at an inlet and a cooling roller at an outlet so that two flat surfaces of the belts overlap each other. It is described that the transfer material with toner is provided in two stages and the overlapping portion of both belts is conveyed from the inlet to the outlet to carry out fixing.

If both the heating roller and the pressure roller are hard surface rollers, it is considered that the endless belt is thin and almost hard, and the recording paper on which the toner image is adhered is conveyed between them. As a result, the part that receives the contact pressure is almost a linear narrow part, and the contact is often uneven due to floating vibrations, etc., and the thermal expansion state of the recording paper (transfer material) varies. .. As a result, the recording paper is likely to be wrinkled.

[0006]

SUMMARY OF THE INVENTION According to the present invention, stable wrinkle-free gloss fixing can be performed without the thermal fixing property of the toner image being dependent on the material and thickness of the recording paper (transfer material), and the offset can be obtained. An object of the present invention is to provide a fixing device which can obtain a high-quality color toner image without transfer.

[0007]

This object is achieved by any one of the following technical means a, b, c, d and e.

(A) An upper end is provided with an internal heating roller, a heating endless belt containing a peeling roller, and a lower part is provided with a pressure roller and a conveying endless belt containing a peeling roller, and the pressure roller comprises both endless belts. The first nip area is a heating device in which the transfer material carrying the toner image is heated and pressed so that the peeling rollers contact each other via both endless belts. The fixing device is formed by a pressure roller, and the second nip region is formed by contacting a pressure guide member from the inside of the heating endless belt.

(B) An upper end is provided with an internal heating roller, a heating endless belt including a peeling roller, and a lower end is provided with a pressure roller and a conveying endless belt including a peeling roller, and the pressure roller includes both endless belts. A fixing device that presses a transfer material carrying a toner image by heating and pressing the transfer material carrying a toner image so that the peeling rollers contact each other via both endless belts. The fixing device is formed by both pressure rollers, and the second nip region is formed by contacting a pressure guide member from the inside of the pressure endless belt.

(C) An upper end is provided with an internal heating roller, a heating endless belt containing a peeling roller, and a lower part is provided with a pressure roller and a conveying endless belt containing a peeling roller, and the pressure roller comprises both endless belts. A fixing device for pressing a transfer material carrying a toner image by heating so that the peeling rollers contact each other via both endless belts. The fixing device is characterized in that the line connecting both shaft centers is inclined by 15 to 40 ° with respect to the vertical line so that the pressure roller is on the upstream side so that the first and second nip regions are formed.

(D) An upper end is provided with an internal heating roller, a heating endless belt including a peeling roller, and a lower end is provided with a pressure roller and a conveying endless belt including a peeling roller, and the pressure roller includes both endless belts. A fixing device for pressing a transfer material carrying a toner image by heating so that the peeling rollers contact each other via both endless belts. The fixing device is characterized in that the line connecting both shaft centers is inclined by 15 to 40 ° with respect to the vertical line so that the pressure roller is located on the downstream side so that first and second nip regions are formed.

(E) An upper heating endless belt including an internal heating roller and a peeling roller is provided at an upper portion, and a pressure endless conveying endless belt including a peeling roller is provided at a lower portion, and the pressing roller includes both endless belts. A fixing device for pressing a transfer material carrying a toner image by heating so that the peeling rollers are in contact with each other via both endless belts. And a second nip region formed by a pressure roller or a heating roller at an overlapping portion of the heating endless belt and the pressure endless belt.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the first invention of the present invention is a side sectional view showing the nip region of FIG. 1, a side sectional view of the entire structure of FIG. 2, and FIG.
10 is an exploded perspective view of the cooling unit of FIG. 10, a sectional view of the fixing roller (heating or pressure) of FIG. 10, a sectional view of the layer structure of the belt of FIG. 11, a toner viscosity / temperature characteristic curve of FIG. 12, and a temperature control of FIG. circuit diagram,
Will be explained.

300 to 600 W, preferably 400 W in the core
An endless belt 25 is wound so as to enclose the heating roller 11 having the heat source heater 14, the peeling roller 21, and the tension roller 22. The tension roller 22 can also be used to control the skew of the belt 25. The outer diameters of the peeling roller 21 and the tension roller 22 are 5 to 20 mm, and in this embodiment, they are 10 mm. And pressure roller 3
1, an endless belt 25B is wound so as to enclose the peeling roller 21A and the tension roller 22A. The pressure roller 31 presses the heating roller 11 via the belts 25 and 25B. Further, the downstream peeling roller 21 of the pressure roller 31,
Air-cooling devices 40 and 50 are arranged above and below the belts 25 and 25B up to 21A, respectively. The pressure roller 31
The distance from to the peeling roller 21 is 120 to 150 mm. Both endless belts are in close contact with each other from the heating / pressurizing roller to the peeling roller and run in the same direction, and the transfer material can be sandwiched between and conveyed from the inlet to the discharge position.

As shown in FIG. 10, on the surface of the heating roller 11, a silicone rubber layer is coated as a heat resistant synthetic rubber layer 12 having a thickness of about 2 to 5 mm on a pipe-shaped core metal 13 to have an outer diameter of 40 mm. was soft rollers are formed, formed is pressurized by the pressure roller 31 is a hard roller, which is easily crushed soft roller surface, a narrow non-nip region N ₁ the angle theta _1, as shown in FIG. 1 is doing. The pressure roller may be a hard roller as described above, but may be a soft roller having a hardness larger than that of the heating roller. In this case, the rubber layer covered with a fluorine tube having a thickness of 50 μm is used to increase the hardness. Further, as shown in the cross-sectional view of FIG. 8, the behavior of the pressure contact portion nip region is such that the smooth curvature of N ₁ and N ₂ can be passed, and the variation in thermal expansion of the recording paper (transfer material) is also a constant value. The recording paper (transfer material) is not wrinkled. A heater 34 is also provided on the core of the pressure roller 31.

Further, the included angle θ of the overlapping portion of the both endless belts 25 and 25B with respect to the heating roller 11 or the pressure roller 31 is θ.
₂ is formed. Then, a second nip area N ₂ is formed.
The length of the first nip region N ₁ is 3 to 20 mm, more preferably 3 to 10 mm, and the length of the second nip region N ₂ is 5.
.About.50 mm, more preferably 10 to 35 mm.

There are various ways of forming the second nip region N ₂ , but in one embodiment of the first invention, the contact surface 71 of the pressing guide member 70 is formed from the inside of the heating belt 25 as shown in FIG. Both belts 25, 25
Forming the nip area N ₂ is pressed by the embracing angle theta ₂ to the circumferential surface of the pressure roller 31 B. A friction coefficient between the contact surface 71 and the back surface of the heating endless belt 25 is selected to be small, or a concave groove is provided in the belt feeding direction of the guide member 70,
Keep the smoothness of belt 25.

The recording paper (transfer material) 61 carrying the toner 62 is sandwiched between the endless belts 25 and 25B along the inlet guide 18, and an air cooling box having a fan 53 of a lower air cooling device 50 in the middle thereof. It is conveyed while being cooled by a guide plate 51 with an opening (louver) 57 provided in the upper part of 52 and an air-cooling box 41 having a fan 43 of an upper air-cooling device 40, at the peeling roller 21 from the belt 25. After being separated, it advances between the upper and lower guides 23A and 23B and is discharged by the discharge roller pair 24. In this way, the recording paper (transfer material) 61 and the toner 62 on the way are sandwiched between the endless belts 25 and 25B, cooled from the upper side and the lower side thereof, and easily separated and collected from the belt 25.

Here, in one embodiment of the first invention, the contact surface 71 of the heating endless belt of the pressing guide member 70 is more specifically replaced with the lower surface 41A of the air cooling box 41 of the upper air cooling device 40 as shown in FIG. be able to. That is, the air-cooled box
41 is pressed against the heated endless belt 25. A large number of air circulation holes are formed in the contact surface 41A of the air cooling box 41 so that the heating endless belt 25 is cooled from the back surface.

Further, the outer diameter is 20 mm above the heating roller 11.
A cleaning roller 16 and a small amount of oil roller 17 are provided.
36 are provided. Foam sponge rollers made of silicone rubber or urethane rubber are used for these rollers.

Further, static elimination brushes 26, 26A and 27 are provided immediately after the return belt portion near the peeling roller and the discharge roller pair 24 are discharged. In a portion of the lower air cooling device 50 near the pressure roller 31, a gap 56 formed between the air cooling box 52 and a guide plate 51 having an opening (louver) 57, a duct 41 of the upper air cooling device 40, and a heating roller 11. Since the gap 46 with the endless belt 25 on the side closer to is small, the cooling air is jetted toward the heating roller 11 and the pressure roller 31 to cool the surface of those rollers and reduce the heating efficiency. I try not to lose it.

Further, temperature sensors 25A and 25C are provided in the vicinity of the peeling roller 21 on the upstream side (rear surface) of the endless belt, and the temperature detection sensors 19 and 25C are provided near the surface of the heating roller 11 and the surface of the pressure roller 31, respectively. 39 are provided respectively.

Both endless belts 25 and 25B are formed by coating a transparent polyimide resin substrate 28 with a release layer 29 made of silicone rubber having high elasticity as shown in FIG. Thickness is 25-75 μm, overall thickness is 25
The belt width is set to ~ 150μm and 310mm. However, the release layer 29 of silicon rubber may be omitted in the heating endless belt 25B.

Next, the operation of the fixing device 1 thus constructed will be described.

First, the viscosity / temperature characteristic curves of the linear polyester toner and general polyester toner shown in FIG. 12 will be described.

In this graph, the vertical axis represents the viscosity in common logarithmic values in Poise units, and the horizontal axis represents the temperature. The linear polyester toner is shown by a solid line, and the general polyester toner is shown by a broken line. Both toners have a high viscosity of about 100,000 poise around 100 ° C, that is, a glass transition state, and both toners are in a molten state when the temperature exceeds 100 ° C. The optimum molten state has a viscosity of 5000
It's about Poise. As for the viscous state, the heating temperature of a general polyester toner reaches 150 ° C., but that of a linear polyester toner is 120 ° C., which is a much lower temperature.

Further, in the present invention, the heating endless belt 25 and the pressurizing endless belt 25B intervene, as compared with the conventional fixing device in which the heat fixing is performed by the nip of only two roller pairs of fixing rollers. As a result, since the temperature lowering time until peeling can be secured, the melting temperature can be expanded to a higher temperature than before, and the heating region can be made much wider. In this heating region, the unfixed image is sufficiently melted by a toner such as a linear polyester resin which is melted at a low temperature. The recording paper (transfer material) 61 and the toner 62 are separated from each other by the adhesive force between the toner 62 and the recording paper (transfer material) 61 in the molten state and the airflow from the cooling fans 43 and 53 applied from the front and back sides of the transfer material. The endless belts 25 and 25B are conveyed while being sandwiched between them, and the temperature is lowered due to the temperature drop of the belt itself and the cooling effect of the airflow.

In this area, the toner 62 and the recording paper (transfer material) 61, which have been sufficiently cooled to have a large viscosity and become in a glass transition state, are bent portions of the both endless belts 25 and 25B supported by the peeling rollers 21 and 21A. Is peeled off from the belts 25 and 25B. At this time, since the toner 62 is almost in the solidified glass transition state, the surface property of the belt 25 is maintained as it is, and a glossy surface close to a mirror surface is obtained. In this way, the toner 62 is solidified after it is sufficiently melted, so that color reproducibility by melting and mixing a plurality of color toners can be ensured, and the transparency when fixed on OHP or the like can also be stably ensured. As mentioned above, at least the heated endless belt
Since the surface material constituting 25 is a material such as silicone rubber which is a release agent, the release layer itself has elasticity as well as releasability, so that uniform heating and pressurization to the toner can be realized and the toner 62 and Even if it is a very small amount between the endless belt 25 and the release layer, it has a damper effect, and even if a toner such as a linear polyester toner that easily melts at a relatively low temperature is used, the offset state is completely lost. It does not occur, or even if it does occur, it can be kept at a level within a range where cleaning is possible.

Further, a sensor as a temperature detecting means provided along the outer peripheral surface of the heating roller 11 and the pressure roller 31 on which the endless belts 25 and 25B are hung, which does not correspond to the belt conveying path.
Although the temperature control is performed by the contact of 19, 39, the surface of both endless belts 25, 25B is never damaged by the sensors 19, 39 as an advantage that cannot be overlooked. On the contrary, the heating endless belt 25 is only on the surface thereof.
Since 25 and the toner 62 are in contact with each other and the toner does not spread around the back surface, the toner 62 does not adhere to the sensor 19 to cause a detection failure.

Further, in the case of a fixing device using both endless belts 25 and 25B, the temperature of the fixing portion is likely to be affected by the states of the upper air cooling device 40 and the lower air cooling device 50, but the pressure roller 31 for pressure bonding is used. Sensor as a temperature detector attached to the
By controlling the heating of the heater by matching the reading value of 39 with the reading value of the sensor 19, it becomes possible to keep the temperature of the fixing portion in a stable range.

The nip length N ₁ is required as follows.
This is to prevent the thermal expansion of the recording paper (transfer material) 61 from being uniformly distributed and to prevent wrinkles, and to uniformly press and melt the upper end (inner side) of the heating endless belt 25. Toner 62 and heating endless belt 25 when heated from
Melting at the interface with is guaranteed. However, if excessively heated, the toner 62 spreads and the toner image is disturbed. And cooling becomes difficult.

Next, the nip length N ₂ is required to sufficiently heat the transfer material 61 to melt the toner 62 and soak the transfer material 61 into the transfer material 61 to improve the fixing property. It seems to be from.

The heating of the toner side is carried out in a relatively short time to suppress the deterioration of the image quality. Therefore, it is not necessary to apply a large pressure to the nip portion and the toner 62 may be melted. It is important that the substrate side of belt 25 be slowly heated to obtain sufficient toner adhesion.

From the experimental results, it was not preferable that N ₂ was smaller than N ₁ . Further, if N ₂ is too large with respect to N ₁ , the toner image will be too melted and the quality will be deteriorated. Further, if N ₂ / N ₁ becomes too large, the angle between the inlet side and the outlet side of the transfer material 61 will become too large. Further, N ₂ / N ₁ cannot be set too large in order to ensure a sufficient cooling area of the recording paper (transfer material) 61. Making it too large leads to hindering the miniaturization of the device. Then, depending on the type of recording material, the occurrence of curls and wrinkles becomes more remarkable as N ₂ / N ₁ increases.

Further, if N ₂ is made too large, the driving torque becomes large, so it is desirable to avoid it.

By thus setting 1 ≦ N ₂ / N ₁ ≦ 3, it becomes possible to stably achieve sufficient penetration of the toner 62 onto the transfer material and fixation with sufficient gloss,
Despite the sufficient melting and gloss of the toner,
The offset transfer of the toner to the heated endless belt 25 is eliminated, and the fact that the subsequent recording paper (transfer material) 61 is contaminated due to the offset transfer can be practically eliminated. Then, high-quality image fixing can be stably achieved.

Here, the internal heating roller 11 is provided with the heater 14 at the core as described above, but the pressure roller 31 is also provided with the heater 34 at the core.

Then, in the vicinity of the temperature detecting sensor 19 and the peeling roller 21, which are provided on the circumference of the internal heating roller 11 at a position where the endless belt 25 is not applied, the heating endless belt 25 and the pressurizing endless belt 25B are brought into contact with each other on the upstream side. According to the detection information of the temperature detection sensors 25A and 25C provided so as to be in contact with the temperature detection sensor 19 provided so as to be in contact with the circumference of the pressure roller 31, the heating heater 14 of the heating roller 11 and the heating of the pressure roller 31 are heated. The heater voltage of the heater 34 and the voltages of the cooling fans 43 and 53 are controlled.

Further, since a layer having poor heat conduction is inserted between the heater 14 and the sensor 19, the temperature detection ripple tends to be extremely large. In such a state, it becomes impossible to control the actual surface temperature.

In order to avoid this, a temperature detection sensor
19 may be omitted in the case of the first embodiment. Therefore, when attaching the sensor 19, it is preferable to attach a sensor having a large time constant.

Further, in the present invention, the internal heating roller 11
The outermost layer is covered with a rubbery soft layer 12 as shown in the sectional view of FIG. As a result, the pressure roller 31 having a harder surface is pressed against the endless belts 25 and 25B and the recording paper (transfer material) 61, and the soft layer is dented to form the nip area N _1. The nip region N ₂ is formed by the included angle with the pressure roller, and the transfer material 61 is conveyed in a state where the heat transfer is sufficiently large and the heat capacity is sufficiently large. The transfer material 61 includes a heating roller 11 and a pressure roller.
Since the fixing roller 31 is sandwiched between the endless belts 25 and 25B and passes through both areas of the nip, there is no sudden temperature change after exiting both areas of the nip. Therefore, the recording sheet (transfer material) 61 is stably fixed without passing through the fixing device without being wrinkled.

Contrary to this, when the hard rollers are brought into line contact with each other or in a hard state close to this as in the conventional case, rapid heating and cooling are repeated and the thermal expansion change is rapid, so that wrinkles are generated. It was easy.

A circuit diagram of the above temperature control is shown in FIG.

Heating endless belt 25 and pressure endless belt 25B
Of the pressure roller 31 according to the readings of the temperature detection sensors 25A and 25C provided in contact with the back surface near the peeling portion of the sheet and the temperature detection sensors 19 and 39 provided in contact with the heating roller 11 and the pressure roller 31. Heater 34 and heating roller 11 at the core
The temperature of the temperature detecting sensors 19 and 39 is controlled by controlling the voltage of the heater 14 at the core of the device. However, the control of the heater 14 is switched by SW depending on the type and thickness of the recording paper (transfer material) 61. Also, if necessary, an air cooling device
The ON / OFF control of the 40 and 50 fans is incorporated, and the ON / OFF of the endless belt drive M is also incorporated.

Further, the ON / OFF control is performed according to the preparation, the printing, the printing and the like.

Next, one embodiment of the second invention is shown by the side sectional view of FIG.

The second nip region N ₂ is formed so that the heating roller 11, not the pressure roller 31, holds the overlapping portion of the two endless belts 25, 25B. Therefore, from the inside of the pressurizing endless belt 25B, the contact surface of the pressing guide member 70A
71A is pressed and brought into contact with the belt 25B and the heating endless belt 25.
The overlapping portion of the above is held by the heating roller 11 at the included angle θ ₂ so that the second nip region N ₂ is formed. Here, a material having a small friction coefficient between the contact surface 71A and the pressureless endless belt is selected. The first equipment is equipped with other components.
2 is a side sectional view of the overall configuration of the embodiment of the invention of FIG. 2 and shows the same effect.

Further, in the embodiment of the second invention shown in FIG. 3, the contact surface 71A of the pressing guide member 70A to the pressurizing endless belt is more specifically a side sectional view showing the whole of FIG. 2 or FIG. It can be replaced with a guide plate 51 with an opening (louver) 57 provided in the upper part of the air-cooling box 52 as shown in the perspective view of FIG. The pressureless endless belt 25B is cooled from the back surface through the opening hole (louver) 57.

Next, an embodiment of the third invention will be described with reference to the side sectional view showing the nip region in FIG. 4 and the partial sectional view of the heating / pressurizing roller pressing portion in FIG.

This is because the angle between the straight line connecting the axes of the heating roller 11 and the pressure roller 31 and the vertical line is α ° and the pressure roller 31
Is when the transfer material 61 is on the upstream side in the transport direction.

In this embodiment, the first nip area N ₁ and the second nip area N ₂ can be formed by the inclination angle α. The mounting arrangement and functions of the other members such as cooling, cleaning, charge removal, temperature sensor, inlet guide, upper and lower guides for outlet, and discharge roller are almost the same as those of the first and second inventions. Omit it. The second nip area N ₂ is formed by the overlapping portion of the endless belts 25 and 25B being held by the heating roller 11. Further, as a means for increasing or adjusting each hugging angle θ ₂ , a pressing guide member 73 may be provided and pressed upward from the inside of the pressureless endless belt 25B.

Further, as compared with the heating roller 11, a pressure roller
With the arrangement of 31, the holding angle θ ₂ with respect to the heating roller is formed by the overlapping portion of the endless belts 25 and 25B, and the nip area N ₂
Are formed. The length of the nip area N ₁ is 3 to
20 mm, more preferably 3 to 10 mm, and the length of the nip region N ₂ is 5 to 50 mm, more preferably 10 to 35 mm.

The angle α is larger than 15 ° and 40
It is desirable to be smaller than 30 °, and 30 ° is most suitable.

Next, an embodiment of the fourth invention will be described with reference to side views showing the nip region in FIGS. 6 and 7 and a partial cross-sectional view of the heating / pressurizing roller pressing portion in FIG.

This is because the angle between the straight line connecting the axes of the heating roller 11 and the pressure roller 31 and the vertical line is α °, and the pressure roller is
This is the case where 31 is on the downstream side in the transport direction of the transfer paper 61.

In this embodiment, the first nip region N ₁ and the second nip region N ₂ can be formed in the same manner as in the third invention by the inclination angle α. However, unlike the case of the third invention, the second nip region N ₂ is formed by the pressure roller 31 holding the overlapping portion of the endless belts 25 and 25B. The mounting arrangement and functions of the other members are the same as those in the above-mentioned embodiments.

Further, a pressing guide member 74 is provided as a means for making the holding angle θ ₂ of the second nip region N ₂ larger or adjustable, and pressing is performed below the inside of the heating endless belt 25. be able to.

Further, with respect to the heating roller 11, a pressure roller
With the arrangement of 31, the wrapping angle θ ₂ between the endless belts 25 and 25B to the pressure roller is formed, and the endless belt 25
Forms a nip region N ₂ . The length of the nip area N ₁ is 3 to 20 mm, more preferably 3 to 10 mm,
The length of the nip area N ₂ is 5 to 50 mm, more preferably 10 to 35
mm.

The angle α is larger than 15 ° and 40
It is desirable to be smaller than 30 °, and 30 ° is most suitable.

As described above, the first, second, third of the present application
In a fourth aspect of the invention, the first nip region N ₁ formed by the heating and pressing rollers 11 and 31 and the overlapping portion of the heating endless belt 25 and the heating endless belt 25B are formed by the pressing roller 31 or the heating roller 11. The second feature is that it has a _second nip area N ₂ .

The temperature control of each part in each of the above-mentioned inventions is basically the same as in the first invention.
It is performed based on the circuit diagram of 13.

[0062]

With the fixing device of the present invention, transfer of offset stains and wrinkles does not occur, and high-quality image transfer without gloss and bleeding, especially color image transfer, is performed on the material and thickness of the recording paper (transfer material). It has been possible to achieve stable performance without depending on, and to make the fixing device compact and low cost.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a nip region in the first invention.

FIG. 2 is a side sectional view showing the whole one embodiment of the first invention.

FIG. 3 is a side sectional view of an embodiment of the second invention.

FIG. 4 is a side sectional view of an embodiment of the third invention.

FIG. 5 is a partial cross-sectional view of a crimp portion according to another embodiment of the third invention.

FIG. 6 is a side sectional view of an embodiment of the fourth invention.

FIG. 7 is a side sectional view showing the whole one embodiment of the fourth invention.

FIG. 8 is a partial cross-sectional view of a crimping portion according to another embodiment of the fourth invention.

FIG. 9 is an exploded perspective view of the cooling unit according to the present embodiment.

FIG. 10 is a sectional view of a heating roller.

FIG. 11 is a sectional view showing the layer structure of an endless belt.

FIG. 12 is a toner viscosity / temperature characteristic curve.

FIG. 13 is a circuit diagram of temperature control.

[Explanation of symbols] 1 Fixing device 11 Heating roller 14,34 Heater 16,36 Cleaning roller 17 Trace oil roller 18 Inlet guide 19,39 Temperature detection sensor 21,21A Peeling roller 22,22A Tension roller 23A, 23B Vertical guide 24 Ejection Roller pair 25,25B Endless belt (Heating endless belt) 26,26A, 27 Static elimination brush 31 Pressure roller 40,50 Air cooling device 41 Air cooling box (duct) 43 Fan 46,56 Gap 51 Guide plate 52 Air cooling box 53 Fan 57 Opening Hole (louver) 61 Recording paper (transfer material) 62 Toner 70,70A, 73,74 Pressing guide member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Haneda Konica stock company, 2970 Ishikawa-cho, Hachioji, Tokyo (72) Inventor Toshinori Yamazaki 2970 Ishikawa-machi, Hachioji, Tokyo Konica, stock company (72) Inventor Masakazu Fukuchi 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock company (72) Inventor Shizuo Morita 2970 Ishikawa-cho, Hachioji-shi, Tokyo Konica stock company

Claims (5)

[Claims] 1. A heating endless belt including an internal heating roller and a peeling roller at the upper portion, and a conveying endless belt including a pressure roller and a peeling roller at the lower portion, wherein the pressure roller is provided through both endless belts. Is a fixing device that presses the internal heating roller into contact with each other so that the peeling rollers contact each other via both endless belts, and heats and presses the transfer material carrying the toner image. The fixing device is formed by both rollers, and the second nip region is formed by contacting a pressing guide member from the inside of the heating endless belt. 2. An upper end having an internal heating roller, a heating endless belt containing a peeling roller and a lower end having a pressure roller and a conveying endless belt containing a peeling roller, the pressing roller interposing both endless belts. And a peeling roller contacting each other via both endless belts to heat and press the transfer material carrying the toner image. The fixing device is formed by a pressure roller, and the second nip region is formed by contacting a pressure guide member from the inside of the pressureless endless belt. 3. An internal heating roller at the upper part, a heating endless belt containing a peeling roller and a conveying endless belt containing a pressure roller and a peeling roller at the lower part, wherein the pressure roller is provided through both endless belts. A fixing device that presses a transfer material carrying a toner image onto the internal heating roller under pressure so that the peeling rollers contact each other via both endless belts. The line connecting the axes is 15 to 15 against the vertical line so that the pressure roller is on the upstream side.
A fixing device characterized by being inclined by 40 ° so that a first and a second nip region are formed. 4. An internal heating roller at the upper part, a heating endless belt containing a peeling roller, and a conveying endless belt containing a pressure roller and a peeling roller at the lower part, wherein the pressure roller is provided through both endless belts. A fixing device that presses a transfer material carrying a toner image onto the internal heating roller under pressure so that the peeling rollers contact each other via both endless belts. The line connecting the axes is 15 with respect to the vertical line so that the pressure roller is on the downstream side.
A fixing device characterized in that the first and second nip regions are tilted by -40 °. 5. An internal heating roller at the upper part, a heating endless belt including a peeling roller, and a conveying endless belt at the lower part, which includes a pressure roller and a peeling roller, wherein the pressure roller is provided through both endless belts. And a peeling roller contacting each other via both endless belts to heat and press the transfer material carrying the toner image. And a second nip region where an overlapping portion of the heating endless belt and the pressure endless belt is formed by a pressure roller or a heating roller.