JPS62206574A - Fixing device - Google Patents

Abstract

PURPOSE:To attain a good fixing capacity with the low consumption of electric power by inhibiting the operation of an air cooling means provided on the outside of a fixing device when an image is formed but permitting this operation when the image is not formed. CONSTITUTION:A heat discharge fin 530 as the air cooling means is provided near an image carrier 1 on the outside of a fixing device 5 and is connected to a control circuit 532 through a driving circuit 531. A detecting circuit 533 which detects whether the image forming operation, namely, the copying operation is performed or not is connected to the control circuit 532. The control circuit 532 inhibits the operation of the heat discharge fan 530 by the signal from the detecting circuit 533 when the copying operation is performed, but the circuit 532 permits the operation of this fan when the copying operation is not performed. Since the operation of the air cooling means is inhibited when the image forming operation requiring a sufficient heat is performed, the heat efficiency is improved and the good fixing capacity is attained with the low consumption of electric power as the whole.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fixing vi device used in image forming apparatuses such as electrophotographic copying machines and printers.

(Prior Art) Conventionally, this type of fixing device uses a pair of fixing rollers, at least one of which has a heat source such as a halogen heater, to sandwich and convey a support such as copy paper carrying an unfixed image. There is a roller fixing device that fixes the unfixed image.

The fixing roller is warmed up by being rapidly heated until it reaches a predetermined temperature by energizing the heating source at the same time as the power of one image forming apparatus is turned on.

The surface temperature of this fixing roller is detected by a temperature detection element, and once it reaches a predetermined temperature after warming up, the current to the heating source is controlled to maintain that temperature, ensuring stable fixing at all times. It maintains its sexuality.

By the way, heat is emitted from the heated fixing roller by conduction heat or radiant heat through its support and drive member, so the temperature inside the machine increases significantly, causing thermal deterioration and thermal damage to electrical and mechanical parts. In addition, there is a problem in that blocking of toner in the cleaner or developing device occurs.

Therefore, in order to solve the above-mentioned problems, a heat exhaust fan is provided behind or to the side of the fixing device, and the heat exhaust fan is constantly rotated when the power is turned on to prevent the temperature inside the machine from rising.

(Problem to be solved by the invention) However, in the case of such conventional technology, the heat exhaust fan is generally rotated at all times when the power is turned on.
In addition, the heat exhaust fan always rotates during copying to heat the fixing roller to a predetermined temperature. Therefore, the first thing in the morning after the power is turned on, the heat exhaust fan is rotated even though the inside of the machine is cold, which cools down parts such as the fixing roller, resulting in a very poor thermal efficiency of about 30 to 45%. It was something. Therefore, immediately after the power of the apparatus is turned on, the fixing roller is not sufficiently heated, resulting in a problem that the fixing performance of copies is very poor compared to that in a steady state. Particularly in energy-saving high-speed machines, the guaranteed number of sheets to be fixed for continuous copying immediately after the power is turned on is significantly reduced.

Therefore, in order to solve this problem, the set temperature of the fixing roller is set higher than the normal set temperature for a predetermined period of time immediately after the power is turned on to accelerate the temperature rise of the roller.
It has been proposed that heat is also applied to the pressure roller side by rotating the roller pair during weighting, thereby improving fixing performance.

However, in the former case, the wait time becomes longer.

Moreover, not only does this have the disadvantage of shortening the life of the fixing roller and the parts that come into contact with it, but also the exposure lamp of the optical system is turned on and the motors are operated during copying, so the image forming apparatus itself requires 100V and 15A. With such limited electric power, there is a limit to increasing the wattage of the heater that heats the fixing roller, and this is still insufficient when performing high-speed processing. Furthermore, in the latter case, the rewait time becomes longer. Furthermore, there is a drawback that the life of parts in the fixing device is shortened, and problems such as noise are likely to occur.

Therefore, in conventional high-speed machines, the current situation is to detect the temperature of the rollers and stop copying when the temperature drops below a predetermined temperature to prevent fusing failures. The problem of poor fixation remained unresolved.

In addition, the thermal efficiency mentioned here means what is expressed by the following formula.

Thermal efficiency η= (Wrota+ −Wloss(T))
Xl 00/WTotal (%) wlo, s= (HaN/HoN+Horr) x
wy, t, 1 (W) where WfOtal: Total power of the heating source in the fixing device (W) Wloss (T): Amount of heat released when the roller pair is idly rotated at the roller temperature T ("C) ) HON: ONI, time of heating source HOFF: 0FFI, time of heating source The present invention was made to solve the problems of the above-mentioned prior art, and its purpose is to An object of the present invention is to provide a usable and highly efficient fixing device that achieves good fixing properties.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a fixing device including a pair of rollers, at least one of which has a heat source. The apparatus is configured to include a control means for prohibiting the operation of the provided air cooling means when one image is being formed, and permitting the operation when no image is being formed.

(Example) The present invention will be explained below based on illustrated embodiments.

FIG. 7 is an explanatory diagram showing an image forming apparatus to which the fixing device according to the present invention can be applied.

In the figure, 103 is a document, 104 is a document lamp for illuminating the document 103, and 105 is an imaging optical system including a plurality of mirrors, lenses, etc. assembled together. Reference numeral 1 denotes an image carrier consisting of a cylindrical photosensitive drum, which is pivotally supported so as to be rotatable in the direction of arrow a in FIG.
Surroundings are a negative charging device 107, a developing device 108. A transfer charger 2 and a cleaner 110 are provided. Further, a fixing device and the like are arranged around the image carrier 1, but P in FIG. 0, which is omitted for convenience of explanation, is a transfer material.

In this image forming apparatus, an original 10 is placed on the surface of an image carrier l uniformly charged by a negative charger through an imaging optical system.
Image 3 is formed to form an electrostatic latent image. Then, this electrostatic latent image is made visible by the developing device 108, and the visible image on the image carrier 1 is transferred to the transfer material P by the transfer charger 2.
The image is fixed in a fixing device.

FIG. 1 is an explanatory diagram showing an embodiment of a fixing device according to the present invention.

In the figure, a transfer material P such as a copy paper onto which a toner image T has been transferred is separated from an image carrier 1 by a separation charger 3, and is transported to a fixing bag W5 by a transport belt 4.

The fixing device 5 includes a heating roller 501 and a pressure roller 50.
2, and the pressure roller 502 has a heating roller 50
1 by a known pressure means at least during fixing. This heating roller 501 has a heat-resistant elastic material layer such as silicone rubber or fluorine rubber on the outer peripheral surface of a hollow cylindrical roller core made of metal such as aluminum, stainless steel, or copper.
A layer thickness of 0.05 to 2 m is provided, and preferably a layer of heat-resistant mold release resin such as PFA or PTFE is provided on top of the layer to a thickness of 3 to 2 m.
It is provided with a thickness of lo07tm. The heating roller 5
A heating heater 503 such as a /\logen heater and an auxiliary heater 503' are disposed inside the hollow part 01, and the auxiliary heater 503' is normally in an OFF state and operates only at startup after power is turned on. On the other hand, the pressure roller 502 has two to one layers of heat-resistant elastic material such as silicone rubber, fluorosilicone rubber, or fluorosilicone rubber on the outer peripheral surface of a hollow cylindrical roller core made of metal such as aluminum, stainless steel, or copper.
Provided with a thickness of 0 mm, preferably further on the top layer, 3 to 1
It is made of a heat-resistant mold-releasing resin layer made of PFA, PTFE, etc. with a thickness of oOILm. The reason why the heat-resistant elastic layer of the pressure roller 502 is thick in this way is to form a protrusion in the pressure contact area between the pressure roller 502 and the heating roller 501 . The hollow interior of the pressure roller 502 is provided with a low heating heater 503'' such as a halogen heater.

A temperature detection element 504 such as a thermistor or a thermocouple is arranged in contact with the outer peripheral surface of the heating roller 501, and the detection signal is guided to a known control means (not shown), and the control means controls the heater 503. By controlling the voltage and the like, the temperature of the outer peripheral surface of the heating roller 501 is maintained at the toner image melting temperature.

Further, a cleaning member 50 is provided on the outer periphery of the heating roller 501 for removing foreign matter such as offset toner and paper dust attached to the surface of the heating roller 501 from the surface of the heating roller 501.
5 is provided. This cleaning member 505 is
A cleaning web 5051 made of a heat-resistant nonwoven fabric such as Nomex, Himeron, or polyester is transferred to the supply roll 5.
054 onto a take-up roll 5053 and is brought into contact with the heating roller 501 by a pressing roller 5052. This cleaning web 5051 is
When the take-up roll 5053 is driven to rotate by a driving means (not shown), the cleaning web 5051 is pulled out from the supply roll 5054 little by little while changing its contact position, so that a new surface of the cleaning web 5051 is always brought into contact with the heating roller 501. Contact. Further, if the cleaning web 5051 is impregnated with an anti-offset liquid such as dimethyl silicone oil, the cleaning effect can be further enhanced.

Further, around the heating roller 501, curved reflecting plates 506 and 506' having heat reflection properties are arranged close to each other in the entire longitudinal direction. The reflecting plate 506' is disposed so as to cover the entire surface of the heating roller between the roller 5052 and the entrance opening for the transfer material P.
The heating roller is disposed so as to cover the entire surface of the heating roller between the heating roller and a separating claw 508, which will be described later. Above reflector plate 506°506
A thick cover 507゜507' made of a heat insulating material such as glass wool for preventing heat radiation is attached to the outer peripheral surface of the reflecting plate 506゜506' to prevent unnecessary heat radiation from the reflecting plate 506゜506'. . That is, the reflecting plates 506 and 506' and the covers 507 and 507' constitute a covering member for the heating roller 501.

Further, a casing member 509 having a U-shaped cross section is provided above the fixing device 5, and a cleaning member 505,
It surrounds the reflectors 506 and 506', the covers 507 and 507', and the temperature sensing element 504. Another casing 511 having an L-shaped cross section is provided outside this casing member 509 with an air layer 510 in between.

On the other hand, on the pressure roller 502 side, a reflection plate 512 similar to the reflection plate 506 and a cover 513 similar to the cover 507 are provided so as to cover most of the periphery of the pressure roller 502, respectively. Furthermore, a casing 514 similar to the casing 509 is provided outside the force/<-513.

By providing these reflective plates 506, 506', 512 and covers 507, 507', 513, it is possible to reduce heat wasted from the surfaces of the heating roller 501 and pressure roller 502, and also to detect temperature. The temperature measurement performance of the element 504 can be stabilized. Therefore, temperature control for the set temperature of the heating roller 502 can be stabilized, and power consumption can be reduced.

A guide plate 515 that guides the transfer material P toward the heating roller 501 is provided near the ends of the reflective plate 506 and the reflective plate 512 that are close to each other.

The guide plate 515 is made of a heat insulating resin such as PBT.

By the way, the transfer material P having the unfixed toner image T is conveyed while being sandwiched between the rollers 501 and 502 before being heated and pressed, and the toner image T is formed into a permanent image on the paper surface by the heat applied by the heated rollers 501 and 502. The image is fixed as a fixed image, and is ejected from the apparatus while being held between the paper ejection rollers 517 and 518.

In order to reliably separate the transfer material P from the heating roller, a plurality of separating claws 508 are provided on the discharge port side of the heating roller 501 so as to contact the roller surface along the roller axis direction. Further, the separation claw 508, which is provided on the discharge port side of the pressure roller 502 so that the separation claw 508' comes into contact with the surface of the roller 502, is attached to the casing 509°51.
The one-separation claw 508' is also held by a support plate 520 that is spaced apart from the casing member 514. These separation claws 50i, 50
8' uses 520' as a pivot point when clearing a jam, etc.
Support plate 519, 520 and paper ejection roller pair 517° 518
It is movable integrally with the roller pair 501 and 502 so as to separate from the pair of rollers 501 and 502.

As the reflecting plates 506, 506', 512, it is desirable to use a metal plate with 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 chrome plating. Board 506, 50
The shape of 6', 512 preferably has a curvature concentric with the circumferential surface of the roller, and preferably has a relatively thin thickness.

Further, the covers 507, 507', 513 include:
glass wool, rock wool, ceramic fiber,
Alternatively, a single structure or a composite structure of foams such as phenol foam and epoxy foam is preferable.

Incidentally, in this embodiment, a heat exhaust fan 530 as an air cooling means is disposed near the image carrier 1 outside the fixing device 5, and this heat exhaust fan 530 is connected to the drive circuit 53.
1 to the control circuit 532. Further, a detection circuit 533 is connected to the control circuit 532 for detecting whether an image forming operation is in progress, that is, whether a copying operation is in progress. Accordingly, the control circuit 532 is configured to prohibit the operation of the heat exhaust fan 530 during copying and to permit the operation of the heat exhaust fan 530 during non-copying based on the signal from the detection circuit 533.

FIG. 2 shows a cross section taken along line x-xla in FIG. 1.

Heat-resistant heat insulating sleeves 523 and 523' are fitted onto the rotating shafts 524 and 524' of the heating roller 501, respectively.
Bearings 526 and 52 mounted on 25 and 525, respectively
6' is supported. Heat-resistant gears 527 and 527' are fitted onto the rotating shafts 524 and 524', respectively, and one heat-resistant gear 527' is meshed with a driving force transmission gear 528 connected to the driving source M. . Therefore, the heating roller 501 is connected to the driving force transmission gear 52 by the driving force of the driving source M.
8 and a heat-resistant gear 527', and is rotationally driven. A gear 529' fixed to a manual knob 529 is meshed with the other heat-resistant gear 527, and the manual knob 529 is rotatably supported by the frame 525. By manually rotating the manual knob 529, the heating roller 501 is rotated via the gear 529' and the heat-resistant gear 527, and the jammed transfer material P can be removed.

Since the heat-resistant gear 527.527' is made of a heat insulating material, the heating roller 501
27', heat is not dissipated to drive transmission members such as other gears, so this heat-resistant Kia 527.5
By using 27', the heat retention of the heating roller 501 is improved.

Further, the heat-resistant sleeves 523 and 523' are also made of a heat insulating material to prevent heat dissipation due to heat transfer from the ends of the heating roller 501 to the bearings 526 and 526' and the frame 525 and 525'. Therefore, heat loss from the ends of the heating roller 501 is greatly reduced.

Generally, the heat-resistant gears 527, 527' are often provided with a large number of other drive transmission members in conjunction with each other, and therefore, conventional heat loss occupies most of the heat loss in such drive systems. On the other hand, something like this configuration can reduce or eliminate heat loss to the drive system, so
It can greatly improve thermal efficiency and reduce power consumption. In addition, in this configuration, heat-resistant sleeves 524, 524' are used in addition to heat-resistant gears 527, 527', so heat loss from the roller ends to frames 525, 525' can be prevented, and thermal efficiency can be improved. You can improve.

The heat-resistant sleeve may be a heat-insulating material such as polyimide, polyamide-imide, polyamide, pps (polyphenylene sulfide), PBT (polybutylene terephthalate) resin, phenol resin, or a heat-insulating material made of a mixed material of this type. It is preferable that the material be made of a plastic material.

The gears 527, 527' 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 501 is connected to the heat-resistant sleeve 52.
4,524' and the heat-resistant gears 527, 527' provide a thermally isolated state from the machine body and the frame body 525, 525', and the heat loss transmitted through these is extremely small. In this way, thermally isolating the roller from the driving force transmission path is very effective in improving thermal efficiency.

(Experimental Example) With the above configuration, the present applicant actually conducted a fixing test using a fixing device as shown below.

The heating roller 501 has an outer diameter of 59.3 mm, an inverted crown of 150 pm, an aluminum roller core with a wall thickness of 8.5 mm, a silicone rubber with a thickness of 0.5 mm and 2 mm.
A roller coated with 01 Lm thick PTFE is used as the pressure roller 502, and a 5 m thick heat-curable silicone rubber layer and a 30 ILm thick fluoro rubber layer are placed on a stainless steel roller core metal with an outer diameter of 60 m and an outer diameter of 50 m. Each roller was coated with a latex layer.

In addition, the heater 503 in the heating roller uses an 870W halogen heater, and the heater 503' uses a 350W halogen heater, and the heater 503' is used at startup (during weight).
Only the light was turned on. On the other hand, the heater 503″ inside the pressure roller
A 70W sheathed heater was used, and it was turned on only when copying was not being performed.

In addition, the nip width is 9.0 Shimaro, and the heating roller surface temperature is 1.
The temperature was 95°C.

FIG. 3 is a diagram illustrating changes in the surface temperature of each roller with respect to time for the experiment of the above specific example. 0 time 1 = 0
When the power is turned on, the heaters 503, 503' and 503'' light up.The heating roller surface temperature rises as shown in the figure, and when the heating roller surface temperature reaches 170°C (point A), it stops. The two rollers 501 and 502 begin to rotate under pressure, and the surface temperature of the pressure rollers also rises rapidly.

When the surface temperature of the heating roller reaches 195° C. (point B), the fixing state is reached and both rollers 501 and 502 stop rotating. The heating roller 501 is maintained at a surface temperature of about 195° C. by a control means (not shown). On the other hand, since the pressure roller 502 is no longer supplied with heat from the fixing roller, its surface temperature decreases, and about 5 minutes after the fixing ready state (0 point), the pressure roller temperature reaches its lowest.
After that, the temperature gradually rises as it receives heat from the heater 503'' from inside.Therefore, the fixing usage at the 0 point is the lowest.
Therefore, if continuous copying is performed at this 0 point, it is extremely preferable as a comparison experiment of fixing properties.
The table includes the time when the sheet is finished (point D).

The experimental results shown below were conducted under the following common conditions between CD and CD. In other words, the copy speed is 445mm/sec in an environment of 15℃ (A 3 size paper, 4
3 sheets/min), scale 180 g/m2 A solid black of 24 mm in size is arranged in a grid pattern of 3 pieces at equal intervals vertically and horizontally on A3 paper, and 250 sheets are continuously copied, the 1st sheet, 25 sheets Samples were extracted every 25 sheets, such as the 25th sheet, the 50th sheet, and the 250th sheet, and solid black at 9 locations on each sheet was evaluated for fixability.

To evaluate this fixation, use Silpon C (trade name, purchased from Shirupon Paper Co., Ltd.) and rub it back and forth 10 times at a pressure of 40 g/c, and measure the difference in density before and after rubbing with a Macbeth reflection densitometer. It was measured and digitized.

D = Reflection density before rubbing the medium 24 solid black image (1,0
The image density is adjusted so that ≦D≦1.1. ) D': Reflection density after rubbing the φ24 solid chromatic image ΔD: Density reduction rate Then, the fixability was evaluated using the average of the density reduction rates of the 9 solid chromatic parts.

Furthermore, in this experimental example, the heat exhaust fan 530 was operated only during non-copying periods, and the operation of the heat exhaust fan 530 was prohibited during copying periods.

The results of the fixability test under the above conditions are shown in FIG. 4(a).

According to the fixation evaluation method described above, the range in which normal line images exhibit good fixability is when the density reduction rate is 20 to 25% or less.
All 0 sheets showed good fixing properties.

FIG. 5(a) shows the change in the heating roller surface temperature in this case.

In addition, in order to calculate the amount of heat effectively used for copy paper, we calculated the time change in the amount of heat dissipated when the copy paper is rotated idly without paper passing, as shown in Figure 6 (a). Immediately after charging, the idle heat generation amount was 360W. The thermal efficiency η immediately after the power was turned on was 59%. Further, for reference, when the standby state was continued for more than 1 hour, the idle heat generation amount was 115 W, and the thermal efficiency η was 87%. The fixing properties at this point were good even when the set temperature was 180°C.

-"M, there was no problem with lifting and lowering the machine because the heat exhaust fan 530 was operated during standby, that is, when not copying.Also, even if the heat exhaust fan 530 was operated during standby, the fixing device By narrowing the openings on the entry and exit sides of the transfer material P in No. 5 as much as possible, the increase in the amount of heat dissipation could be suppressed to 5 to 20 W.

Further, when the heat exhaust fan 521 was kept in the OFF state all the time, the rise in temperature inside the machine caused malfunctions of various sensors installed in the paper discharge section, blocking of toner in the cleaner, and the like.

(Comparative Example) The same fixing device as in the experimental example was used. However, as the air cooling means, as is conventionally known, a heat exhaust fan (not shown) provided at the rear of the fixing device is always strongly operated, and a heat exhaust fan 521 is used.
and 530 were not used.

Therefore, the results of a fixing test under the same conditions as in the experimental example are shown in Figure 4(b).
When the number of continuous copies was approximately 85, the density decrease rate was less than 20%, and after that, the fixing performance became a problem. Figure 5(b) shows the change in the heating roller surface temperature at this time.
It can be seen that the roller surface temperature drops rapidly.

In addition, the amount of heat dissipated during idling under the above conditions is shown in Figure 6 (
As shown in b), the power was 520 W immediately after the power was turned on, and the thermal efficiency η at this time was 40%, which is worse than the experimental example. Further, even in a steady state when the device is left on standby for more than one hour, the amount of heat dissipated is as high as 315 W, and the thermal efficiency η is 64%, which is significantly worse than 87% in the experimental example.

As described above, in this embodiment, the heat exhaust fan 530 is operated only during non-copying periods and prohibited from operating during copying periods, so that the following effects can be obtained.

■ Even if the heat exhaust fan 530 is operated during standby, if the opening of the fixing device 5 is narrowed as much as possible, the amount of heat dissipated by the convection of the air layer generated by the operation of the heat exhaust fan 530 will be reduced by the heat exhaust fan 530 during the copy operation. 530 is operated, and the useful heat in the fixing device 5 is not wasted.

■By prohibiting the operation of the heat exhaust fan 530 during copying, the useful heat inside the fixing device 5 does not leak to the outside, and thermal efficiency is greatly improved, even immediately after the device is powered on. Not only can sufficient fixing performance be ensured, but power savings can also be achieved. Furthermore, even if the operation of the heat exhaust fan 530 is prohibited during copying, the temperature does not rise rapidly because the transfer material P is transported inside the machine at a temperature approximately equal to room temperature.
If the heat exhaust fan 530 is operated after the copy operation is completed, no problem will occur.

■During copying, the exposure lamp of the optical system lights up and the motors operate, so the power consumption is significantly higher than in standby mode. power to the heater 50 of the fixing device 5
3, etc., and can ensure good fixing performance even in high-speed machines.

In the above embodiment, a case has been described in which the heat exhaust fan 530 is operated all the time during non-copying, but it does not necessarily have to be operated all the time, and the heat exhaust fan 530 may be operated as needed during non-copying. 0For example, ■Prohibit the operation of the heat exhaust fan for a predetermined period of time after the power is turned on,
After a predetermined period of time has elapsed, the heat exhaust fan is operated only in the non-copying state.

(2) A temperature detection element is provided inside the machine, and the heat exhaust fan is operated only when the temperature detected by the temperature detection element is equal to or higher than a predetermined temperature and the machine is in a non-copying state.

You can do it like this.

That is, the present invention prohibits the operation of the air cooling means during copying, while allowing the operation of the air cooling means during non-copying,
The air cooling means is operated as appropriate.

Further, in the above embodiment, the case where one heat exhaust fan is provided has been described, but there may be two or more heat exhaust fans, and if there are multiple heat exhaust fans, at least one may be controlled as in this embodiment. The installation location of the heat exhaust fan is also not particularly limited.

(Effects of the Invention) Kiba Ill has the above-described structure and operation, and the operation of the air cooling means is prohibited during image formation, but is allowed to operate during non-image formation, so that sufficient heat is not required. By prohibiting the operation of the air cooling means during image formation, thermal efficiency can be greatly improved, and that amount of power can be supplied to the heating source, so good fixing performance can be achieved with less power overall. A highly efficient fixing device can be provided.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the fixing device according to the present invention, FIG. 2 is an x-xt cross-sectional view of FIG. Graph showing changes in surface temperature. FIG. 4 is a graph showing changes in the density reduction rate with respect to the number of copies made in the experimental examples of the present invention and comparative examples, and FIG. 5 is a graph showing changes in the heating roller surface temperature with respect to the number of copies made in the experimental examples of the present invention and comparative examples. 6 is a graph showing changes in heat radiation amount with respect to time in experimental examples and comparative examples of the present invention, and FIG. 7 is an example of an image forming apparatus to which the fixing device according to the present invention can be applied. It is an explanatory diagram. Explanation of symbols 5... Fixing device 501... Heating roller 5
02... Pressure roller 503... Heater 509.
...Casing 530...Exhaust heat fan 532...
・Control circuit No. 21 (No. 31 R1)

Claims (1)

[Claims] In a fixing device including a pair of rollers, at least one of which has a heating source, an air cooling means disposed outside the fixing device is prohibited from operating during image formation, and is allowed to operate during non-image formation. A fixing device characterized by comprising a control means.