JPH09114307A - Fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive fixing device eliminating the need of waiting time, having good heat efficiency, restraining the wasteful generated heat radiated from the device to the periphery, economizing power consumption, saving space, having simple constitution and small number of parts, being excellent in assemblability and maintainability, and having high reliability and excellent fixing characteristic. SOLUTION: This fixing device is provided with a light transmissive turning pressuring member 1 holding and pressuring transfer paper 8 carrying a toner image to a counter member, and a light source 3 irradiating the transfer paper 8 passing the member 1. The member 1 is formed to be a hollow cylinder, provided with the light source 3 on its inside and an elliptical reflecting member 4 on its outside, and arranged so that the light source 3 may be at either of two focal points of the member 4 and the transfer paper 8 may be near the other. The light source 3 emits light in timing just before the transfer paper 8 carrying the unfixed toner image 7 advances to the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device which can be applied to a technique that requires heating and pressurization at the same time, and is particularly suitable for application to a fixing technique of electrophotography.

[0002]

2. Description of the Related Art Conventionally, there are the following techniques of this type. That is, (1) as a technique for condensing the light from the light source, a technique using a lens or an elliptical reflector is used, and the light source is at one focus and the transfer paper or the pressure / fixing roller is at the other focus. The technology of arranging the surface has been seen for a long time.

The disclosure of these techniques is disclosed in Japanese Utility Model Laid-Open No. 47-10536 and Japanese Patent Laid-Open No. 51-48344.
JP-A-54-137343, JP-A-55
-110281, JP-A-56-85850, JP-A-56-93754, and JP-A-58-12.
3455, JP-A-5-11650 and the like.

Further, (2) a technique in which a light-transmissive hollow rotating body (glass pipe) is used for a fixing roller, a light source with a reflecting plate is disposed in the fixing roller, and only the pressing portion is irradiated is seen from old times. The disclosure of these techniques is disclosed in Japanese Patent Laid-Open No.
No. 102736, No. 52-106741, No. 64-54071, and No. 1-239.
577, JP-A-3-189672, JP-A-4-1226969 and JP-A-5-165354.

(3) A light-transmissive hollow rotator (glass pipe) is used for the fixing roller, a lens is fixed in the fixing roller, and a light source is arranged outside the fixing roller. There is already known a fixing device configured to concentrate on a pressurizing portion sandwiching a transfer paper by the lens when transmitting (Japanese Patent Laid-Open No. 53-6044).

(4) A solid rotating body (glass rod) is used for the fixing roller, and the light source is arranged outside the fixing roller.
The whole is covered with a reflecting member, and the light from the light source passes through the fixing roller and the front side where reflected light enters the fixing / pressure roller is irradiated to preheat the fixing / pressure roller and the transfer paper. A fixing device configured is already known (Japanese Patent Laid-Open No. 4-25984).

Further, there is (5) a technique using a fixing film or a fixing belt (Japanese Patent Laid-Open No. 2-158778 and Japanese Patent Laid-Open No. 5-72923).

[0008]

However, the fixing described in (1) of the prior art requires both heating and pressurization for fixing, and sufficient fixing by simply condensing and fusing. It has the drawback of not being able to gain strength.

Further, the problem described in (2) has the following problems. 1. Since the light source and the reflector are built in the hollow rotating body at the same time, the diameter of the rotating body cannot be reduced. 2. Furthermore, therefore, the assemblability and maintainability are extremely poor. 3. The local heating of only the pressurizing section means that the cold fixing roller section always comes by rotation, the heating energy required for melting the toner becomes high, and the temperature change during one rotation of the fixing roller becomes large. There is a major drawback that it is difficult to obtain stable fixing. 4. Further, the fixing roller radiates the thermal energy obtained by the rotation after passing through the pressure unit to the surroundings, not only wasting the energy, but also unnecessarily the surrounding space and other devices adjacent to it. There is a big drawback of heating.

Further, the problem described in (3) has the following problems. 5. A lens is required as a separate member. 6. Since the lens is built in the hollow rotating body, the diameter of the rotating body cannot be reduced. 7. The problems of the above-mentioned technology are the same as 2-4.

Further, the problem described in (4) has the following problems. 8. Since the light from the light source has not been condensed onto the transfer paper, there is room for improvement in saving power and preventing wasteful heat generation of the entire fixing device. Furthermore, the problem described in (5) also has the following problems. 9. A film and belt drive mechanism is required separately, which is against space saving, reduction of the number of parts, assemblability, maintainability, high reliability, and cost reduction. 10. Since the pressing force cannot be set high, the fixing characteristics are slightly inferior.

The present invention has been made in view of the above circumstances, does not require a waiting time, has good thermal efficiency, reduces wasteful heat emitted from the device to the surroundings, and saves power consumption.
It is an object of the present invention to provide a fixing device which is space-saving, has a simple structure, has a small number of parts, is easy to assemble and maintain, has high reliability, has good fixing characteristics, and is low in cost.

[0013]

In order to achieve the above-mentioned object, the present invention provides a light-transmitting peripheral pressure member for pressing a transfer paper carrying a toner image against an opposing member and a light-transmitting peripheral pressure member. In a fixing device having a light source that irradiates a transfer paper by passing through a circular pressure member, a light-transmissive circular pressure member has a hollow cylindrical shape, a light source is inside thereof and an elliptical reflecting member is outside thereof. A light source is arranged at one of the two focal points of the elliptical reflecting member, and the transfer paper is located near the other, and the light source is provided immediately before the transfer paper carrying the unfixed toner image enters the apparatus. It is characterized in that it emits light.

Further, a light-transmissive pressure member that presses against the opposing member with the transfer paper carrying the toner image interposed therebetween, and a light source that transmits the light-transmissive circumferential pressure member and irradiates the transfer paper. In the fixing device having the above-mentioned structure, the light-transmitting peripheral pressure member has a solid cylindrical shape, a light source is provided in the vicinity thereof, and an elliptical reflecting member is provided outside the light source to cover both of them. The light source is arranged on one side of the ellipse so that the transfer paper is located near the other side, and the elliptical shape of the elliptical reflecting member causes refraction when the reflected light from the light source enters the solid cylindrical shape and is refracted. It is characterized in that the light is corrected to have a curvature so as to be condensed near the transfer paper, and the light source emits light at a timing immediately before the transfer paper carrying the unfixed toner image enters the apparatus. .

Further, the light source has a reflecting surface along the axial direction inside or outside the glass tube at a predetermined angle portion within the entire circumference of the glass tube covering the heat generating element, and thus it is unnecessary. It is characterized in that it is configured so that light does not reach the part.

With the above arrangement, the light from the light source can be directly and concentrated on the transfer paper, which is a necessary portion, and the elliptical reflection member is arranged outside the pressure member (fixing roller) to cover it. Since the pressure member can be heated by both irradiation and reflected light without letting out the light from the light source, the light from the light source can be effectively utilized without any waste.

Further, since the elliptical reflecting member covers the pressing member (fixing roller), it is possible to heat the pressing member without letting the light of the light source escape, so that the light of the light source is effective without any waste. Can be used for. Further, since the light from the light source can be emitted only within a predetermined angle range, it is possible to avoid irradiation in an unnecessary angle range when incorporated in the device.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to the drawings. 1 is a schematic explanatory view of a first embodiment according to the present invention, FIG. 2 is a schematic explanatory view of a second embodiment according to the present invention, and FIG. 3 is a perspective view of a light source according to the present invention.

In FIG. 1, a fixing roller 1 as a light-transmissive circumferential pressure member is a hollow cylindrical light-transmissive member such as a glass pipe, and an opposing member made of an elastic material such as silicone rubber. The pressure roller 2 is brought into contact with the pressure roller 2 with a predetermined pressing force, and receives a timing command from the main body of the apparatus to rotate around A (rotation direction).

The fixing roller 1 is surface-treated with, for example, a Teflon coating having a good light transmitting property in order to ensure releasability after fixing. Further, a reflecting member 4 is arranged outside the fixing roller 1 and close to the fixing roller 1 so as to cover the fixing roller 1.

The cross-sectional shape of the reflecting member 4 is, for example, an elliptical shape, and is inside the hollow cylindrical shape of the fixing roller 1, and at the same time, it is positioned at one of the two elliptical focal points of the reflecting member 4. The light source 3 is arranged at a position where Also,
The other one of the two focal points is arranged to be substantially at the position of the transfer paper 8.

Therefore, the heat ray emitted from the light source is directly and reflected and condensed on the transfer paper 8 as shown by the arrow in the figure.
The timing at which the light source emits may be immediately before the transfer sheet 8 carrying the unfixed toner image 7 enters the main fixing device, and the fixing roller 1 is immediately preheated by the direct light and the reflected light of the heat rays emitted from the light source. The transfer paper 8 and the unfixed toner image 7 are also preheated. However, at the nip position, the applied pressure and the collected heat rays enable efficient fusion fixing.

According to this method, not only the holding time due to preheating can be substantially eliminated, but also the heat can be efficiently transmitted to the transfer paper by thoroughly condensing it on the transfer paper, so that it remains after fixing. Compared with the conventional technology, heat can be suppressed to a much smaller level, and power consumption can be saved.
It is possible to reduce the size of a device associated with the fixing device, such as a power supply (capacity) and the size of a cooling device. Also, because of its simple structure, it is easy to assemble and maintain.
Low cost and high reliability can be achieved at the same time.

In FIG. 2 showing the second embodiment, a fixing roller 1'is a pressure roller made of a solid cylindrical material such as a glass rod and made of a light transmissive member and made of an elastic material such as silicone rubber. It abuts 2 with a predetermined pressing force, and receives a timing command from the main body of the apparatus to rotate around A (rotation direction).

The fixing roller 1'is surface-treated with, for example, a Teflon coating having a good light-transmitting property in order to ensure releasability after fixing. Further, a reflecting member 4 ′ is arranged outside the fixing roller 1 ′ so as to cover and cover the fixing roller 1 ′ and the light source 3. The cross-sectional shape of the reflecting member 4'is a modified elliptical shape as described below.

The light source 3 is arranged outside the fixing cylinder 1'on the faithful cylinder, and at the same time, located at the other one of the two focal points of the modified elliptical shape of the reflecting member 4 '. Has been done. On the other hand, the other one of the two focal points is arranged to be substantially at the position of the transfer paper 8. still,
The two-dot chain line in FIG. 2 shows an elliptical shape when there is no fixing roller.

Now, the heat ray emitted from the light source is directly and reflected as shown by the arrow in the figure and condensed on the fixing roller 1 ', but when passing through it, it is just transferred by the lens effect of the fixing roller 1'. The elliptical shape of the reflecting member 4'has been modified so that the reflecting surface converges in the vicinity of 8. The light source may emit light immediately before the transfer paper 8 carrying the unfixed toner image 7 enters the main fixing device, and the fixing roller 1'is immediately preheated by the direct and reflected light of the heat rays emitted from the light source. At the same time, the transfer paper 8 and the unfixed toner image 7 are also preheated. Therefore, at the nip position, the applied pressure and the collected heat rays efficiently fuse and fix.

According to this method, not only the waiting time due to preheating can be substantially eliminated, but also the heat can be efficiently transferred to the transfer paper by thoroughly condensing the light on the transfer paper. Residual heat can be significantly reduced as compared with the prior art, power consumption can be reduced, and a device associated with the fixing device, for example, a power source (capacity) can be downsized, and a cooling device can be downsized or eliminated. Is possible.

The above effects are the same as in the case of the first embodiment described above, but in this embodiment, the fixing roller 1'may be a simple solid cylinder, so that the device can be made smaller and the cost can be reduced by further reducing the diameter. The down and independent light sources 3 have the advantages of further improvement in assembly and maintenance, cost reduction, and high reliability. 1 and 2, reference numeral 6 indicates an entrance guide / reflector, 6 indicates an exit guide / reflector, and arrow B indicates an approach direction.

Next, in FIG. 3 showing the light source 3 ', a halogen heater or the like is conventionally used as the light source.
FIG. 3 is a schematic explanatory sectional view, which includes a heat generating (light emitting) body 10 and a glass tube 11. A reflection member 12 is provided on the outer peripheral surface of the glass tube 11 by a predetermined angle by a vapor deposition technique or the like to regulate the emission angle of light emitted from the heating element 10. As a result, if the heat generation amount of the heating element 10 is the same, there is no irradiation on the angular surface portion on which the reflecting member 12 is applied, and the irradiation energy due to the reflection of the reflecting member 12 is added to the other angular surface portions to shine. The effect of increasing the (temperature) is obtained.

In the fixing process, heating is required only up to the nip portion, and after passing through the nip portion, on the contrary, rapid cooling is desired. Therefore, not only can this be realized by using the light source 3 ′ of the present invention, but the relative radiant energy can be reduced more than in the case of using the conventional light source 3, further power consumption can be saved, and it can be attached to the fixing device. It becomes easier to reduce the size of the device, for example, the power supply (capacity) and the size of the cooling device. In addition, the structure is the same, and the advantages of being able to achieve assembly, good maintainability, and cost reduction and high reliability are not hindered.

[0032]

As described above, according to the present invention, the preheating time of the pressure roller can be shortened so that the electrophotographic apparatus requires substantially no waiting time. Further, since the light from the light source can be effectively utilized to the maximum extent, power consumption can be saved, wasteful heat dissipation to an adjacent device can be reduced, and devices attached to the fixing device, such as a power supply (capacity) and a cooling device, can also be used. It is possible to reduce the size and weight. Further, the structure is simple, the assembling and the maintainability are good, and the space saving and the low cost can be realized. If the pressure member is solid and the light source is arranged outside, the diameter of the pressure member can be reduced, which is advantageous in terms of space, cost, and maintenance. Furthermore, if a light source partially having a reflecting surface along the axial direction is used, the light from the light source can be irradiated in a limited angular range, so that it is possible to avoid irradiation in an unnecessary angular range when incorporating the device. it can. Further, since the reflected light can be utilized, the irradiation energy can be increased in the required angle range. Or low input energy is enough to obtain the same irradiation energy.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a first embodiment according to the present invention.

FIG. 2 is likewise a schematic illustration of a second embodiment.

FIG. 3 is a perspective view of a light source according to the present invention.

[Explanation of symbols]

 1, 1'Fixing roller 2 Pressure roller 3, 3'Light source 4, 4'Reflecting member 7 Unfixed toner image 8 Transfer paper 10 Heating element 11 Glass tube 12 Reflecting member

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yutaka Shio 10-3 Kitamura, Tottori City, Tottori Prefecture Ricoh Microelectronics Corporation

Claims (3)

[Claims] 1. A light transmissive peripheral pressure member that presses against a facing member with a transfer paper carrying a toner image sandwiched therebetween, and a light source that transmits the light transmissive peripheral pressure member and irradiates the transfer paper. In the fixing device having, the light transmissive circumferential pressure member has a hollow cylindrical shape, a light source is provided inside thereof, and an elliptical reflecting member is provided outside thereof, and one of two focal points of the elliptical reflecting member is provided. A fixing device characterized in that a light source is arranged so that the transfer paper comes near the other, and the light source emits light at a timing immediately before the transfer paper carrying the unfixed toner image enters the device. 2. A light-transmissive circumferential pressure member that presses against a facing member with a transfer paper carrying a toner image interposed therebetween, and a light source that transmits the light-transmissive circumferential pressure member and irradiates the transfer paper. In the fixing device having, the light transmissive circumferential pressure member has a solid cylindrical shape, a light source is provided in the vicinity thereof, and an elliptical reflecting member is provided outside the light source to cover both of them. The light source is arranged in one of the two, and the transfer paper is arranged in the vicinity of the other, and the elliptical shape of the elliptical reflecting member is such that when the reflected light from the light source enters into a solid cylindrical shape and is refracted, A fixing device characterized in that the refraction light is corrected to have a curvature such that it is condensed near the transfer paper, and the light source emits light at a timing immediately before the transfer paper carrying the unfixed toner image enters the device. . 3. The light source has a reflecting surface along the axial direction inside or outside the glass tube at a predetermined angle portion within the entire circumference of the glass tube covering the heating element, 3. The fixing device according to claim 1, wherein the fixing device is configured so that light does not reach the portion.