JPH03188475A - Heating and fixing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat fixing device used in a recording device such as an electrophotographic device or an electrostatic recording device.

[Prior art]

Conventionally, heating devices that use heat have had difficulty achieving uniform heating and power consumption. In particular, in a heat roller fixing device, which is a typical type of fixing device, heat from a heating source installed in an image forming device or a fixing device is transmitted through the heat roller surface and is lost without affecting fixing. A problem existed. As a result, heat loss increases at the ends of the heat roller, resulting in a significant decrease in fixing performance.

On the other hand, in conventional technology, in order to compensate for the temperature drop at the end of the heat roller or the end region of the pressure roller that comes into pressure contact with the heat roller, the heat generation distribution of the heat source is configured to be strong ( This increases the amount of power supplied to the fixing device, which necessitates limiting power consumption to other departments and complicating temperature control in the fixing device.

On the other hand, even with this solution, the amount of heat lost from the end of the heat roller increases further, which causes a rise in temperature inside the image forming device, which can cause toner blocking in the cleaner and developer, and cause plastic damage inside the device. This may cause thermal deformation of the molded part.

Another solution is to provide a heat insulating sleeve only between the frame member that holds the heat roller and the heat roller in order to reduce the heat loss mentioned above, but this was not a satisfactory solution in the end. This is not a solution, and the heat loss is large, resulting in temperature sag at the end.

The conventional method described above not only wastes power but also causes temperature rise in other parts of the main body, causing various problems.

[Purpose of the invention]

The present invention aims to improve the above conventional drawbacks,
It is an object of the present invention to provide a heat fixing device that can obtain good fixing performance with less electric power.

A feature of the present invention is that the heat loss wasted from the heating roller is significantly reduced compared to the conventional method, and heat retention is improved.

[Embodiments of the invention]

The present invention will be described below with reference to the drawings, and a fixing device to which the present invention is particularly effective will be described in detail.

FIG. 1 is an explanatory diagram of an embodiment of the present invention. This figure shows a toner image T formed by electrophotography using a heat fixing device.
The figure shows the one in which the image is fixed on plain paper P.

2 is a heating roller that has a heating heater 3 such as a halogen heater inside, and rotates in the direction of the arrow in response to driving force from a drive motor (not shown). 2 is heater 3 for low heating
A pressure roller with a built-in roller presses against the heating roller 1 and rotates by sliding.

This heating roller 1 has a heat-resistant mold release resin layer such as tetrafluoroethylene resin provided on the outer peripheral surface of a hollow roller core made of metal such as aluminum, stainless steel, or copper to a thickness of 20 to 89 microns. The pressure roller 2 is rotatably supported on bearings 15,15'.

This roller 2 is pressed against the heating roller 1 by a known pressure means at least during fixing, and has a relatively thick layer of elastic material such as silicone rubber, fluorosilicone rubber, or fluorosilicone rubber on the outer peripheral surface of a metal roller core. . One purpose of this configuration is to secure a pressure contact area d with the heating roller. A temperature sensing element 4 such as a thermistor or thermocouple is disposed in contact with the outer peripheral surface of the heating roller 1, and its detection signal is guided to a known control means (not shown) to control the temperature of the outer peripheral surface of the heating roller 1 ( The toner image is maintained at the melting temperature by controlling the output of the heater 3 or the voltage applied thereto.

Reference numeral 6 denotes a cleaning member for removing foreign matter such as offset toner and paper powder adhering to the surface of the heating roller from the roller surface, and a cleaning web 61 made of heat-resistant nonwoven fabric such as Nomex or Himeron is used.

The cleaning web 6 is brought into contact with the heating roller by an elastic pressing roller 63. Further, this web 61 is driven by a winding roller 6 (not shown) that is driven.
5, the cleaning web 6 is moved from the supply roller 6□ by a small amount to change its contact position, so that a new surface of the cleaning web 6 is always brought into contact with the heating roller. The web 6 moves on the rollers 64 interposed after the pressing roller 63, is reversed toward the supply roller 6□, and is wound around the winding roller 65 with the front and back sides reversed. Furthermore, if the cleaning web 6□ is impregnated with an anti-offset liquid such as dimethyl silicone oil, the cleaning effect can be further enhanced.

7 is a curved reflector having heat reflection properties, and heating roller 1
It is provided near the periphery of the heating roller 1 over the entire longitudinal direction of the heating roller 1. Further, the reflecting plate 7 has a width so as to cover the space between the position of the pressing roller 63 on the circumferential surface of the heating roller 1 and the entrance opening for the paper P.

Reference numeral 8 denotes a thick cover for preventing heat radiation, which is provided in close contact with the entire convex surface of the reflecting plate 7 to prevent wasteful radiation of heat from the reflecting plate 7. Reference numeral 16 denotes a casing member on the upper side of the fixing device, which surrounds the cleaning member 6, the reflection plate 7, the cover 8, and the temperature sensing element 4. The temperature sensing portion of the temperature sensing element 4 is located closer to the roller 1 than the reflecting plate 7 is.

On the other hand, a reflecting plate 9 similar to the reflecting plate 7 is also provided on the pressure roller 2 side.
A cover 10 similar to the cover 8 is provided to cover most of the circumferential surface of the pressure roller 2.

By providing the reflector 7.9 and the cover 8.10, it is possible to reduce the heat wasted from the surfaces of the heating roller and the pressure roller, and to stabilize the temperature measurement performance of the temperature sensing element 4. can be converted into Furthermore, temperature control for the set temperature of the heating roller 1 can be stabilized and power consumption can be reduced.

Reference numeral 22 denotes a guide plate that guides the paper P toward the heating roller l side, and the reflection plate 7
The heating roller 1 is provided close to the heating roller 1 so as to be located between one end of the reflecting plate 9 and the reflecting plate 9. A support plate 24 supports the pressure roller, and the pressure roller is pressed against the fixing roller by the spring 23.

Now, the plain paper P having the unfixed toner image T is conveyed while being held between the heating and pressure side rollers 1 and 2, and the toner image T is fixed by the heat applied by the surface temperature of the rollers 1 and 2, and then the paper is discharged by the paper ejection roller. It is ejected out of the device while being held by 20 and 21. On the discharge port side of the heating roller, a plurality of separating claws 5 are provided in contact with the roller surface along the roller axis direction in order to reliably separate the plain paper P from the heating roller.

Also, a separating claw 51 is provided on the discharge port side of the pressure roller 2.
is placed in contact with the surface of the

The separation claw 5 is connected to the support plate 1 in a separated state from the casing member 16.
8, and the separating claw 51 is also held by a support plate 18I that is separated from the casing member 17 on the lower side of the fixing device.

The casing member 17 is spaced apart from the reflector 9 and cover 10 of the pressure roller 2 and is provided so as to cover them.

The reflecting plate 7.9 is preferably made of a metal having a glossy surface, such as an aluminum plate with a polished surface, a copper plate, or an iron plate with a surface treatment such as Cr plating. The shape of the reflecting plate 7.9 is preferably one having a curvature concentric with the circumferential surface of the roller, and the thickness thereof is preferably relatively thin.

The covers 8 and 10 are preferably made of glass wool, rock wool, ceramic fibers, or foams such as phenol foam and epoxy foam, or are made of a composite material.

Next, the configuration of the end portion of the heating roller 1 will be described in detail with reference to FIG. 2, which is an explanatory diagram of the fixing device taken along the line xx' in FIG. 1.

11 and 11' are the rotation shafts 10. and 11' at both ends of the heating roller l, respectively.
Heat-resistant sleeves 1'1, respectively, are fitted in contact with bearings 12,12' respectively mounted on the fuser frame 13,13'. Reference numerals 14 and 14' designate heat-resistant gears that are fitted onto the rotating shaft l8.1'1 of the heating roller 1, respectively, and transmit the driving force from the driving source M. This heat-resistant gear 14' meshes with another drive transmission gear 25, and rotates together with the heating roller 1 in response to the driving force. The heat-resistant gear 14 includes gear 26. of the manual knob 26. are engaged and manual driving force is transmitted.

Since the heat-resistant gear 14.14' is made of a heat-insulating material, the heating roller 1
Heat will not be dissipated to other drive transmission members such as gears via '. This gear improves the heat retention of the heating roller 1.

Furthermore, the heat-resistant sleeve 11, 11' is also a heat-insulating material, and extends from the end of the heating roller 1 to the bearing 12.
．． 12' and the frame 13. This prevents heat loss due to heat transfer to the frame 13 and 13'. Therefore, the heat loss from the end of the heating roller 1 can be reduced compared to before by the heat-resistant gear 14.14', and can be further reduced significantly or almost eliminated by the addition of the heat-resistant sleeve 11.11'. I was able to do that.

Generally, the heat-resistant gear 14, 14' is often provided with a number of other drive transmission members so as to interlock with the heat-resistant gear 14, 14'. Therefore, conventional heat losses are predominant in such drive systems. On the other hand, the above embodiment can reduce or eliminate heat loss to the drive system, so
It can greatly improve thermal efficiency and reduce power consumption. In addition, in the above embodiment, a heat resistant sleeve 1311' is used in addition to the heat resistant gear 14, 14', so that heat loss from the roller end to the frame 13, 13' can be prevented and thermal efficiency can be further improved. .

The above heat-resistant sleeves are made of polyimide, polyamideimide, polyamide, PPS (polyphenylene sulfide), PBT (polybutylene terephthalate).
It is preferable to use a heat-insulating material such as a resin or phenol resin, or a heat-insulating material made of a mixed material of this type. The gears 14 and 14' may be made of a heat-resistant material with good heat insulation properties, such as polyimide, polyamide-imide, PPS, modified phenol, or tetrafluoroethylene with a reinforcing optical fiber added. preferable.

As mentioned above, the heating roller l has a heat-resistant sleeve 11.1.
1' and heat-resistant gears 14, 14', the machine is thermally isolated from the machine body and the frame 13, 13', and the heat loss transmitted through these is extremely small.

Next, specific numerical examples of embodiments according to the present invention will be explained.

In the fixing device with the above configuration, the heating roller 1 has an outer diameter of φ60,
Aluminum core metal wall thickness 7mm, surface layer 35μ thick PF
A coating is used as a weeping roller and a pressure roller 2, with an outer diameter of φ60
A heat-vulcanized silicone rubber coating with a wall thickness of 5 mm was applied onto a stainless steel core metal having a diameter of 50 mm using a welding roller.

The heater 3 in the heating roller is a 650W halogen heater and is normally turned on, and the heater 3' in the pressure roller is a 650W halogen heater.
The 0W sheathed heater turns on only when not copying.

Further, the pressing area d was 11 mm %, and the heating roller surface temperature was 180°C.

FIG. 3 is a diagram illustrating a change in the surface temperature of each roller over time for the experiment of the above specific example. time 1=0
When the power is turned on, the heaters 3 and 3' are turned on. As shown in the figure, when the heating roller surface temperature rises and reaches 150°C (point A), both rollers 1 and 2, which had been stopped, begin to rotate under pressure, and the pressure roller surface temperature also rapidly increases. Rise.

When the heating roller surface temperature reaches 180° C. (point B), fixing becomes possible and both rollers 1.2 stop rotating. Then, the heating roller 1 is heated to 180° C. by a control means (not shown).
The surface temperature is maintained at the same temperature as before and after. On the other hand, since the pressure roller 2 is no longer supplied with heat from the fixing roller, its surface temperature decreases.

Approximately 5 minutes after the fixing ready state (point 0), the pressure roller temperature reaches its lowest temperature, and then gradually rises as it receives heat from the heater 3' from inside. Therefore, the fixing ability at the 0 point is the lowest. Therefore, if continuous copying is performed at this zero point, it will be extremely preferable as a comparative experiment of fixing properties. This figure shows the temperature change when 99 sheets were continuously copied at point 0, including the time when 99 sheets were completed (point D).

The experimental results shown below were conducted under the following common conditions between CD and CD. In other words, copy speed 405mm/sec (A3 size paper,
35 sheets/min), weighing 80 g/m'' A solid black of φ24 was formed on A3 paper, and 1.6.11.
16th sheet, 8 sheets every 10th sheet from 21 to 91, total 1
Two sheets were selected, and nine locations on each sheet were used as experimental subjects. The fixing properties of these 12 sheets, 9 locations each, for a total of 108 locations, were evaluated using Kojin Wiper (product name, Koshiiri Co., Ltd., Paper Waste).
The sample was rubbed back and forth 10 times at a pressure of 40 g/cm' using a Macbeth reflection densitometer, and the difference in density before and after the rubbing was measured and quantified using a Macbeth reflection densitometer.

D: Reflection density before rubbing the φ24 solid black image (1,0
The image density is adjusted so that ≦D≦1.1. ) D': Reflection density after rubbing the φ24 solid black image (
The image density is adjusted so that 1.0≦D≦1.1. ) ΔD: Density reduction rate -11] Table 1 below shows the structural requirements of each fixing device.

It was done.

Table 2 shows the results of the fixing performance of each of the above-mentioned fixing devices, and the numbers indicate how many locations (out of 12 sheets x 9 locations and 108 locations) where the density reduction rate was greater than the predetermined (15, 10, 5)%. This is what is shown.

Table 2 The uniform heater 3 of the fixing device Nα1 to Nα5 has a heat generation length of 3
A 30 mm uniformly wound heater was used. The 200% heater of the fixing device Nα6 is a heater with a large heat generation distribution in the center as shown in FIG. 4 (similar to the configuration of the heater 3 shown in FIG. 2). Furthermore, even if a uniformly wound heater with a heat generation length of 297 mm or less (that is, a heater that is shorter than the maximum paper passing length, and more preferably 20 mm to 80 mm shorter than the maximum paper passing length) is used instead of the 200% heater, the difference between As is clear from Table 2, the fixing devices Nα1 to NcL6
The fixing properties become better as more favorable conditions are added.

■Comparison between Nα1 and Sō2 and &4 and Nα7,■
Comparison between Nα4 and Nα5 and between No. 4 and No. 7, ■N
Particularly remarkable differences are seen between α5 and Nα6 and between Nα4 and 1lJL17.

(2) is the effect of providing the heat radiation prevention member and the reflective member, (2) is the effect of establishing a thermal barrier, and (2) is the effect of the heat generation distribution of the heater.

Also, when comparing the fuser Nα3.1lJI14, Nα4
It is understood that it is more effective to prevent heat loss in the drive system. Also, fixing unit 2, Nα3, Nα
By comparing No. 4, the effect of providing a thermal barrier is confirmed, and when it comes to Nα5 and Nα6, the establishment of that thermal barrier is what gives an additional effect.

Table 3 Table 3 shows the comparison results of wait time (time from turning on the power until fixing becomes possible) in these fixing devices. As we move from the fuser Nα1 to the floor 6, the wait time is similarly reduced as heat loss is prevented.

In other words, it is possible to reliably achieve power savings. or,
While the time required until the temperature distribution over the entire length of the roller becomes stable and uniform is almost impossible to measure on floor 1, it can be rapidly reduced as the temperature is improved from N117 or N112 to Nα6.

Further, FIG. 5 shows a temporal change in the amount of heat released by the fixing device Nαl and the fixing device Nα5.6 during standby. As is clear from the figure, the heat dissipation amount of the fixing device Nα6 stabilizes at about 170 W after 1.5 hours, while the heat dissipation amount of the fixing device Nα6 stabilizes at about 50 W within 1 hour.

In this way, by providing a heating means that generates a large amount of heat in the central portion, or by using a heating means that makes the area occupied by the portion that gives a heat amount smaller than the maximum passage area of the recording material used, the heating fixing roller It becomes easy to equalize the surface temperature of surfaces such as the like. One of the reasons for this is that the heat used in the recording material can be immediately replenished, and the temperature rise in the non-passing region or end region of the recording material can be alleviated. Such a heating means is particularly effective in the fixing device of this embodiment, which reduces heat loss such as heat dissipated from the end region to other drive systems, support frames, etc.

The heat radiation prevention member and reflective member in the structure refer to the reflector plate 7.9 and cover 8.10 in the embodiment shown in FIG. 2, and their presence or absence is indicated. In addition, the term "thermal barrier" refers to a means for preventing heat conduction (e.g., a member made of a heat-resistant, heat-insulating material) between the roller and the frame and/or between the roller and the drive system. It is.

Note that the fixing device Nα7 has a thermal barrier between the roller and the drive system as in the above embodiment, and as shown in Table 3 below, it has a better effect than other configurations alone. This prevents heat loss and improves fixing performance.

Here, the calorific value distribution shown in FIG. 4 will be explained.

As described above, the heater 3 in FIG. 2 has a 150 mm continuous generating zone 31 (75 mm on each side) symmetrically centered on the center of the heating roller, as described above. Further, the heater 3 has a heat generation area with a total length of 320 mm, and has continuous heat generation zones 32 at both ends of the heat generation zone 32 mm.
Several heat generating parts (not shown) are provided at equal intervals between the 13□.

The amount of heat generated by the heater 3 is 40 to 200% as shown in FIG. 4 (corresponding to each heat generating zone and heat generating section), and the central portion of the heater 3 as a whole has a convex shape.

By using such a heater 3, the heating roller 1
Heat transfer occurs from the center to the ends of the heating roller 1.
Above, the entire area shows a nearly -like temperature distribution.

If the fixing action is performed in this state, even if the temperature of the heating roller decreases due to the toner image or recording material, no abnormal temperature rise will occur at the end of the roller, and the heater 3 will bring the surface temperature of the heating roller to the temperature required for fixing. Can be maintained.

Other embodiments of the present invention will be described in detail below with reference to FIGS. 6 to 12. For the sake of overall explanation, the explanation of the same parts as in the configuration of FIG. 2 will be omitted so that the features of each embodiment will be clear.

The embodiment shown in FIG. 6 is characterized in that the above-mentioned heat-resistant gears 14 and 14' are constructed as follows.

In this example as well, the heat-resistant gear 14.14' is fitted onto the rotating shaft 10.1'1 of the heating roller 1.

These gears 14 and 14' each have an inner layer 14 a s made of a heat-resistant resin with good heat insulation properties and provided only on the inner side.
14 a ′, and outer layers 14 b and 14 b ′ made of metal and forming a gear portion on the outer side thereof. The metal of the outer layers 14b, 14b' is preferably a metal that has excellent mechanical strength and is inexpensive in terms of cost, and iron is used in this example. This gear 14.14' is the inner layer 14aS14a'
The outer layers 14b and 14b' are integrally molded by injection molding. This gear 14' is connected to the other drive transmission gear 2.
5, and rotates together with the heating roller 1 upon receiving the driving force from the driving source M. Further, a gear 261 of a manual knob 26 is engaged with the gear 14.

The manual knob 26 is rotated by the operator when the heating roller 1 is desired to be rotated manually, such as when removing a paper jam.

The gears 14 and 14' have a heat shielding property in the portion that contacts the rotation shaft 1 of the heating roller 1, so that the heating roller l
Dissipation of heat through the gears 14, 14' to other drive transmission members such as gears can be largely prevented.

The heat-resistant sleeve 11,11' further has heat-insulating properties and prevents heat transfer losses from the end of the heating roller 1. Therefore, from the rotating shaft 11 to the bearing 12.12'
and heat transfer to the frame 13, 13' is significantly reduced or almost eliminated.

Said gear 14.14' and said heat-resistant sleeve 11.11
'The thermal floating state of the heating roller 1 is made more reliable, but the gear 14.14 relative to the heating roller 1
Considering the strength, it is preferable that the shape of ' is as shown in FIG.

In the example shown in FIG. 7, if a groove 140' is cut in the outer layer made of metal having the tooth surface of the outer gear 14' and then an inner layer 14a' made of heat-resistant resin is molded, the strength is excellent and high torque can be transmitted. Even in such cases, peeling between the metal part and the resin part will not occur.

It is preferable to provide an engaging portion to increase the strength of the heat-resistant resin and the metal portion in this manner.

Next, the embodiments shown in FIGS. 8 to 11 will be described. These are explanatory diagrams of the driving part and the supporting part of the heating roller 1, but the invention is not limited to this, and a more preferable embodiment may be provided if the other end of the heating roller is also provided with the same structure as shown in FIG. It goes without saying that. Only the main parts will be described below, but the other configurations may be those shown in FIG. 2 or similar thereto.

In the embodiment shown in FIG. 8, the heat-resistant gear 141 has a three-layer structure,
The intermediate layer 14□b is made of a heat insulating material to provide heat insulation, and the inner layer 141a and the outer layer 141c on both sides thereof are made of iron, which is a metal. This inner layer 14, a is provided to increase the strength of the fitted state of the heating roller with the rotating shaft 11. The middle layer 14□b is the inner layer 14. outer layer 14, c which is provided thicker than a and receives drive from the drive source M;
and inner layer 14. Blocks heat transfer with a. This inner layer 141a
The intermediate layer 14 made of a heat insulating material is preferably thinner.
If 1b has sufficient strength, it is not necessary to provide the inner layer 14+a. This inner layer 14. If a is made of metal, it should not come into contact with the support means (bearing 12a or sleeve 11a) that rotatably supports the heating roller 1. In this example, the sleeve lla is also made of heat insulating material, so
The inner layer 14.8 is sleeved to prevent heat loss.
It is made to have the same thickness as or less than the sleeve lla, and comes into contact with the sleeve lla and rotates together with the sleeve lla.

Even with the configuration shown in FIG. 8, the effects and explanations described above can be obtained.

The embodiment of FIG. 9 is a more specific embodiment of the present invention, in which a member made of a heat insulating material such as the sleeve lla and the heat insulating sleeve 11, 11' is used as the gear 14' (see FIG. 2). It is integrated with a heat-resistant drive transmission member.

In the figure, the gear 14□ is made of a heat-insulating material, and the rotating shaft 1. The rotary shaft II rotates integrally with the rotary shaft II. gear 1
42 is provided up to the portion where the bearing 12a supports the heating roller 1, receives a drive from a drive source, and slides on the bearing 12a.

Therefore, the bearing 12a rotatably supports the rotating shaft 11 of the heating roller 1 via this gear 14□.

In this way, by providing an integrated heat-insulating member in the part that supports the heating roller 1 and the part that directly transmits the drive of the heating roller 1, not only can the above-mentioned effects be obtained, but also the number of parts can be reduced and costs can be reduced. and ease of manufacturing can be achieved.

The embodiment shown in FIG. 10 is a combination of the embodiments shown in FIGS. 8 and 9, and is intended to reduce costs and increase mechanical strength.

The gear 143 fitted on the rotating shaft 1□ is made by integrating an inner layer 143a made of a heat insulating material and an outer layer 143b made of metal. This inner layer 143a includes a bearing 12a that rotatably supports the heating roller 11 and a rotating shaft 1. from the rotating shaft 11 to the outer layer 143.
conduction heat to the bearings 12a and 12a is significantly reduced or blocked.

This inner layer 143a has a uniform thickness and is provided like a heat insulating sleeve that is in close contact with the rotating shaft 11. In other words, if you look at this gear 143 from another perspective, a --shaped heat insulating layer (corresponding to 143a) is provided in the part to which the drive of the heating roller 1 is transmitted and the part that rotatably supports the heating roller 1. It turns out.

By configuring as described above, the gear 143 can be provided with mechanical strength, and cost reduction can also be achieved. Needless to say, heat loss from the heating roller 1 can be prevented.

FIG. 11 shows a further improvement of the embodiment shown in FIG. In other words, this is an embodiment in which the mechanical strength of the contact portion with the bearing 12a is increased.

The gear 144 fitted on the rotating shaft 11 has a heat insulating inner layer 1
4. a and an outer layer 144b made of metal. This inner layer 144a is the rotating shaft 1. However, the thickness of the portion facing the portion to which the drive is transmitted is thicker than the thickness of the portion facing the bearing 12a.

This was done in order to highly prevent heat loss, focusing on the fact that heat loss is large in the drive system as described above. Further, in this embodiment, the outer layer 144b is configured to be in contact with the bearing 12a. This prevents the inner layer 144a from deteriorating due to contact with the bearing 12a, improves the durability of the gear 144, and ensures that heat loss from the end of the heating roller 1 is prevented over a long period of time.

With this configuration, the mechanical strength can be increased compared to that shown in FIG. 1θ.

The configurations in each of the embodiments shown in FIGS. 8 to 11 may be arbitrarily combined based on the purpose, and a cover made of a reflector or heat insulating material as explained in FIG. 2 may be provided. A more preferred embodiment would be obtained if the heating means were also used as described above or hereinafter. The materials for the above-mentioned heat insulating material and heat-blocking layer include:
Those described for the heat-resistant sleeve 11.11' and the gear 14.14' can be applied.

FIG. 12 shows an embodiment based on the present invention, which is characterized by having a heat insulating member in the support portion of the heating roller in a thermally floating state and the pressure roller 2 that comes into contact with the heating roller as described above. be.

In FIG. 12, gear 14. has a metal gear layer 146b in a portion that receives drive from the drive source M, and a heat-resistant heat insulating layer 14 in a portion that is joined to the rotating shaft 11 and transmits the drive to the heating roller 1.
It has an integrated sa. This heat-resistant insulation layer 146
Further, a is provided between a bearing 12a that rotatably supports the heating roller 1 and a rotating shaft II, and a bearing 11
is in contact with. This prevents heat loss from the end of the heating roller that is driven by the drive source M. Note that the heat insulation layer 14. The thickness of other parts of a is thicker than the part corresponding to the bearing 12a, and the metal gear layer 146b
is spaced apart from the bearing 12a.

Further, a gear 146 having the same structure as the gear 146 is provided at the other end of the heating roller 1, and has a heat-resistant heat insulating layer 14aa and a metal gear layer 146b similar to those described above. This gear 14. is rotatably supported by the bearing 12b, and the metal gear layer 146b engages with a gear 261 that transmits the manual force of the manual knob 26, and transmits the driving force to the heating roller l.

On the other hand, the pressure roller 2 that comes into pressure contact with the heating roller is rotatably supported at both ends by bearings 12c and 12d, respectively. The parts of the roller that come into contact with this bearing 12C112d are covered with sleeves 15a and 15b made of heat insulating material.
is fitted.

The sleeves 15a, 15b have a width larger than the contact width of the bearings 12c, 12d. Thereby, even if the pressure roller 2 is slightly shifted from side to side, heat transfer loss from the ends of the pressure roller 2 can be blocked.

This heat isolation on the pressure roller 2 side is particularly effective not only when the pressure roller 2 has a heat source but also when the pressure roller 2 does not have a heat source.

This is because, if the heating roller side is kept in a thermal floating state, heat loss may occur from the end of the pressure roller that contacts the heating roller. Therefore, by providing a heat shielding member at the end of the pressure roller 2, the thermal floating state of the heating roller can be further improved.

As described above, even in this embodiment, a more favorable effect can be produced by making the heat generation distribution of the heater 3 as described above, or by providing the reflective plate 7 and the cover 8 (insulating).

Further, when a mechanism for transmitting drive is provided on the pressure roller 2 side, the structure provided on the heating roller may be applied to the pressure roller 2 side.

Although the characteristics of each of the above embodiments have been explained, in order to maintain the thermal floating state to a higher degree, it is necessary to improve the performance of the members that come into contact with the rotating body such as the fixing roller, such as the drive transmission gear and the supporting means. Preferably, the entire contact portion is made of a heat-resistant and heat-insulating material.

FIGS. 13 and 14 are embodiments illustrating a heating means that is particularly effective in an embodiment in which the heating roller 1 is brought into a thermally floating state by the various configurations described above. FIG. 13 shows an example of center reference conveyance in which the center of the width of the recording material in the conveyance direction of the recording material to be used (even if the size is different) is aligned with the center, and FIG. 14 shows the recording in the conveyance direction of the recording material to be used. An example of one-sided reference conveyance in which materials are conveyed with their negative ends aligned is shown.

In the figure, 01 is the center line in the longitudinal direction of the heating roller 1 (in Fig. 16, it is the reference line for center reference conveyance), C2 is the reference line for one side reference conveyance, and C3 is the feed of the Japanese Industrial Standard A series size recording material PA. The width center line C4 is the feed width center line of the B-series size recording material PB.

In FIG. 6, 51 is a halogen lamp, and the center line C1
The rollers are arranged symmetrically in the axial direction of the rollers.

The recording material is conveyed so that the center line C1 and the center lines C3 and C4 are on a straight line, and the feeding width of the recording material PA is smaller than that of the recording material PB. 52, 53, and 54 are light emitting parts of the halogen lamp 51. The light emitting part 52 is the longest and gives the maximum amount of heat to the center of the roller. Its length is smaller than the width of the recording material PA, and occupies about 60% of its width. The light emitting section 54 has the width of the recording material PA and the recording material PB.
They are provided at portions corresponding to the difference in width between the two widths. A plurality of light emitting parts 53 are provided between the light emitting parts 52.54 and have the minimum length, and compensate for the heat generation distribution between the light emitting parts 52.54. Furthermore, no light emitting section is provided in the non-passage area of the roller length (the area through which the paper does not pass even if it is the largest size). In this case as well, the heat generation distribution will be as shown in FIG.

By providing the above-mentioned halogen lamp 51, it is possible to provide the necessary amount of heating during central reference conveyance, and it is possible to adequately prevent temperature rise at the ends of the fixing roller. Therefore, the thermal floating state of the heating roller can be further stabilized, and a stable state can be obtained even during continuous fixing during central reference conveyance. Further, the amount of heating by temperature control to obtain this fixing temperature can be reduced compared to the conventional method, and power saving can be achieved.

FIG. 14 shows the above-mentioned one-sided reference conveyance, in which the above-mentioned light emitting sections 52 are provided symmetrically with respect to the center line c3 of recording paper (for example, A4 size) PA, which is commonly used. In this figure, the center lines c1, C3, and C4 are not on a straight line, and the reference line c2 is located at the end of the fixing roller 1. 5
Reference numeral 5 denotes a light emitting section which is longer than the light emitting section 53 and is provided within a portion corresponding to the difference in width between the recording materials PA and PB. A plurality of the light emitting parts 53 are provided at equal intervals in the portion of the maximum width of the recording material excluding the light emitting parts 52 and 55.

Therefore, the heat distribution is at the highest point (the top of the mountain).
is located closer to the reference line C2 than the roller center line C1, and even in the portion corresponding to the light emitting section 55, no light emitting section is provided in the non-sheet passing region of the roller length.

With the above configuration, it is possible to make the thermal floating state of the heating roller 1 more effective, and to obtain stable fixing properties that are not affected by the size of the recording material even in one-sided reference conveyance. Further, since it is possible to prevent the temperature of the end portion of the fixing roller 1 and the area through which the recording material does not pass from increasing, and also to prevent the temperature from decreasing at the end portion, stable fixing performance of the fixing roller 1 can be maintained for a long period of time.

Although FIGS. 13 and 14 described above are limited to the fixing roller 1, this embodiment can also be applied to the pressure roller 2 and other heat rollers of a dry silver type recording device that stabilizes the image by heating. The principle is applicable and heat loss can be prevented as mentioned above.

Therefore, the more the heating roller is thermally floated, the more reliable the amount of heat radiation, prevention of heat loss, improvement of fixing efficiency, speed of thermal stabilization of the heating roller, etc. can be.

Although the above embodiments and specific examples have been described only with respect to the heating roller, the present invention can be applied to the pressure roller 2 or other members involved in fixing.

From another point of view, the present invention is also applicable to image carriers such as photoreceptors that have a heat source.

Although the above embodiments have been described with reference to an internally heated fixing roller, the present invention can also be applied to a fixing roller having an external heating means or a member heated by conduction heat.

As described above, in the above embodiment, a thermal barrier is provided to thermally float the fixing roller (of course, the pressure roller may also be floated), and a heat radiation prevention member and a reflective member are also provided. Furthermore, by increasing the heat distribution of the heater in the center, a fixing device that can achieve good fixing with low power consumption was obtained.

The above embodiment is a preferable example in which a heat-insulating sleeve is provided between the bearing and the heating roller, but it is also possible to use a plain bearing in which the bearing itself has heat-insulating properties, or a heat-insulating sleeve is provided near the bearing. Alternatively, the frame itself may be formed of a heat-insulating material.

The above-mentioned embodiments can be applied as long as supporting means having heat-insulating or heat-insulating properties are provided on members involved in fixing.

More preferably, it is preferable to provide a heat-insulating support means at a location close to a heat-releasing portion, such as around the roller shaft or the roller itself.

In addition, in the above embodiment, the gear attached to the heating roller has a heat shielding property, but the present invention includes a connection system member or a drive system member of a member involved in fixing, such as a heating roller, having a heat shielding property. If it is, it is included. Further, it is particularly preferable to provide the fixing device near the member involved in fixing or on the member itself (not shown, but will become clear from this description).

Furthermore, since the sleeve and gear are constantly in contact with other members, it is preferable that they have wear resistance.

The present invention is particularly effective for equipment that performs heat treatment at high temperatures;
A fixing device that performs heat treatment at a temperature of 0° C. or higher is the most preferable heating device because it provides the special effects (described above).

〔Effect of the invention〕

As described above, the present invention can maintain thermal stability of the rotating body heated by the heating means, and can significantly reduce wasted heat. Further, heat loss from the rotating body can be prevented to a higher degree than in the above invention.

Further, it is possible to easily uniformly heat the object to be heated, to achieve power saving, and to improve the thermal efficiency of heating the object from the heating source.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the xx' cross section of Fig. 1, Fig. 3 is a diagram of changes in roller surface temperature over time, and Fig. 4 is a fuser Nα
6 is a heat generation distribution diagram of the 200% heater, FIG. 5 is an explanatory diagram of temporal changes in the amount of heat dissipated from the fixing device Nα1 and the fixing device Nα6, and FIGS. 6 to 12 are respectively explanations of further embodiments of the present invention. 13 and 14 are explanatory diagrams of main parts of other embodiments according to the present invention. ■... Heating roller 2... Pressure roller 3.3'... Heater 4... Temperature sensing element 6... Cleaning member 7.9... Reflection plate 8.10... Cover 11 .11'...Heat-resistant sleeve 12.12'15.15'...Bearing 13
．． 13'...Frame 14.14'...Heat-resistant gear, between jpi (hrs) Item 13 Ward

Claims (1)

[Claims] (1) A heating rotary body heated by a heating means that heats an unfixed toner image, a first drive transmission system that transmits a driving force from a drive source to this heating rotary body, and a manual drive to the heating rotary body. A heat fixing device comprising a second drive transmission system for transmitting force, wherein both the first drive transmission system and the second drive transmission system are insulated with a heat insulating member.