JP2003307965A - Fixing apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing apparatus having improved durability and capable of attaining an accurate temperature control by improving the heat resistant performance of a non-contact type temperature detecting means for accurately detecting a thermal change, and to provide an image forming apparatus equipped with the fixing apparatus. <P>SOLUTION: As for the fixing apparatus 30 provided with a fixing rotating body 2 heated by a heating means, and the non-contact type temperature detecting means 1 which is arranged in non-contact with the fixing rotating body 2, so as to detect the heat radiated from the fixing rotating body, and wherein the temperature of the fixing rotating body is controlled based on the detection result of the non-contact type temperature detecting means 1, a holder 24 is attached to the means 1 from the outside, and a space part 32 is formed between the outer surface 6a of the non-contact type temperature detecting means and the inside surface 24b of the holder. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device capable of controlling the temperature of a fixing rotating member to be heated, and an image forming apparatus such as a copying machine, a facsimile, various printers or the like equipped with the fixing device.

[0002]

2. Description of the Related Art A fixing device used for fixing image information visualized as a toner image on a recording material on the recording material is a roller member as a fixing rotating member heated by a heater as a heat source or a fixing member. A belt member and a pressure roller as a pressure member are provided. The fixing rotator and the pressure roller face each other and are in pressure contact with each other, and there are contact-type and non-contact-type modes for temperature detection.

In contact-type temperature detection, generally, a thermistor is brought into contact with the roller surface or the belt surface, the surface temperature of these is detected, and the temperature of the roller member or the belt member is controlled according to the detection result. . In such contact-type temperature detection, since the thermistor is brought into contact with the roller member or the belt member, the member surface may be damaged by the thermistor. If the surface of the member is damaged, the rollers and belts need to be replaced, or the fixing device as a whole (unit) must be replaced, leading to an increase in the replacement cost. Since the thermistor is usually attached to the fixing device, the thermistor that can be used is also discarded when the fixing device is replaced, which is not preferable in terms of cost and resource saving. Further, the thermistor is not suitable for responsiveness and is not suitable for precise control. Particularly, in the fixing device in consideration of energy saving, it is required that the electric power is low during the standby time of the device and the fixing temperature rises at a high speed only when the device is used. Therefore, a detecting unit having good responsiveness is required. In a fixing device using a belt, in order to shorten the rising time of a roller member around which the belt is wound, the heat capacity is reduced by thinning the core metal or elastic layer of the roller.

For example, as shown in FIG. 13, a fixing device employing a non-contact type temperature detecting means has a heater 3 as a heat source.
A heating roller 2 having a built-in heat roller, a pressure roller 4 in pressure contact with the pressure roller, and a thermopile 1 as a non-contact temperature detecting means are provided. The toner image carried on the paper 136 is fixed by applying heat and pressure. The thermopile 1 is an infrared sensor that receives heat, that is, infrared rays and converts the infrared rays into an electric signal.
As shown in (b), a can case 6 as a casing having an opening window 5 serving as an infrared ray incident portion serving as a temperature detection surface, and a can case 6 provided so as to close the opening window 5 and allowing infrared rays to pass therethrough. The filter 8 for this purpose, the light absorption part 9 arrange | positioned inside the can case 6, the casing seat surface 6a, and the terminal 7 arrange | positioned on the opposite side to the filter 8. The signal output from the terminal 7 to the outside is input to the control means (not shown).

In the fixing device having such a structure, the infrared rays emitted from the pressure roller 2 are received by the light ray absorbing portion 9 through the opening window 5 of the thermopile 1 and the filter 8.
Then, an electric signal (output signal) is sent from the terminal 7 to a control means (not shown) according to the amount of infrared rays received, and lighting of the heater 3 is controlled according to fluctuation of the output to keep the surface temperature of the heating roller 2 within a certain range. To maintain.

In general, the thermopile 1 has a strong dependence on the environmental temperature, and when the ambient temperature changes, the temperature of the element itself changes correspondingly and the output characteristics also change. The temperature of the heating roller, which is the object to be measured here, is calculated by the following equation. Vout = A (Tb ⁴ −Ts ⁴ ) A: Proportional constant Tb: Temperature of measurement object (K) Ts:
Thermopile temperature (K) For this reason, a thermistor for temperature compensation is built in the thermopile 1, and the temperature of the thermopile is recognized by the output of the thermistor to perform digital or analog correction. Is common. Non-contact temperature sensors that detect infrared rays and output electric signals include pyroelectric sensors in addition to thermopiles.

[0007]

Among the non-contact temperature sensors, the thermopile is affected by the ambient temperature, and therefore the ambient temperature is detected by a thermistor to perform temperature compensation. However, if the responsiveness of the thermistor is poor, it becomes impossible to follow the sudden change in the ambient temperature, the temperature of the measuring object cannot be detected accurately, and the control accuracy deteriorates. For example, when the power is turned on in a cold state in the image forming apparatus provided with the fixing device, that is, in a so-called cold state, the temperature of the heating roller rises rapidly and the ambient temperature of the thermopile 1 near the roller also rises sharply. To rise. Then, the thermistor output changes and the ambient temperature change is detected and corrected.
The ambient temperature is detected low due to the poor response of the thermistor. For this reason, since the temperature of the measuring object cannot be accurately grasped, the temperature cannot be controlled to the set temperature, which may cause a problem in fixing property. In addition, since the maximum operating temperature of the thermopile is generally around 80 ° C., when it is used in a high temperature environment where it may exceed 100 ° C. such as a fixing device, it may not be able to withstand heat and the element may be broken. It is possible. Therefore, in order to use the thermopile as a non-contact temperature detection sensor in the fixing device, it is required to improve heat resistance.

In the fixing device, in order to prevent the occurrence of an offset image, a small amount of silicone oil is applied to the surface of a roller member or a belt member which becomes a fixing rotary member, or a wax is contained in the toner to release the surface. The method of improving the sex is adopted. However, these oils and waxes are evaporated by the heat at the time of fixing and float in the apparatus.
Further, in an image forming apparatus equipped with a fixing device, floating toner or the like is agitated by a fan during printing or copying. When these oils, waxes, and floating toners that become suspended matter adhere to the surface of the infrared ray incident surface of the thermopile such as a filter or lens due to long-term use of the device, infrared rays are absorbed by the adhered matter and the incident amount on the sensor decreases. The phenomenon that the output of the thermopile is lowered occurs. For this reason, the non-contact temperature detecting means such as a thermopile detects the temperature of the measurement target portion lower than the actual temperature, so that the control temperature becomes high as a result of trying to restore the normal temperature and an abnormal image occurs. There are cases. For example, suppose that the fixing temperature is 180 ° C. and the output (Vout) from the non-contact type temperature detecting means corresponding thereto is 2 V, the output drops to 1.8 V due to dirt. That is, since the detected temperature is lowered by 0.2V, a control for returning to 2V works, and as a result, the fixing temperature is controlled near 200 ° C.

An object of the present invention is to improve the heat resistance of the non-contact temperature detecting means capable of detecting a thermal change with high accuracy, thereby improving durability and controlling the temperature with high accuracy, and the fixing device. An object of the present invention is to provide an image forming apparatus provided with the image forming apparatus. An object of the present invention is to provide a fixing device and an image forming apparatus having a good fixing property by stabilizing the fixing temperature of the fixing member. It is an object of the present invention to provide a fixing device capable of preventing dirt from adhering to the detection surface and controlling the temperature accurately, and an image forming apparatus equipped with this fixing device.

[0010]

A fixing device according to the present invention is provided with a fixing rotator heated by a heating means and a heat radiated from the fixing rotator in a non-contact state with the fixing rotator. A non-contact temperature detecting means for detecting the temperature of the fixing rotator based on the detection result of the non-contact temperature detecting means, the non-contact temperature detecting means has a holder mounted from the outside, The outer surface of the non-contact temperature detecting means or the inner surface of the holder so that a space is formed between the outer surface of the non-contact temperature detecting means and the inner surface of the holder when the non-contact temperature detecting means and the holder are mounted. It is characterized in that at least one of the above is formed.

A feature of the fixing device according to the present invention is that the space portion is formed so as to surround the outer surface of the non-contact temperature detecting means, and the holder has a holding portion for holding the non-contact temperature detecting means and a space portion. An air intake is formed in communication with the air supply.

The fixing device according to the present invention is characterized in that the holder has a plurality of ribs which support the non-contact temperature detecting means on the temperature detecting surface side of the non-contact temperature detecting means, and communicates with the space portion on the temperature detecting surface side. And an air discharge port that is formed. It is preferable that the air outlet is formed so that the air is guided to the temperature detection surface because the cooling layer and the shielding layer for the temperature detection surface can be formed by the air.

The feature of the fixing device according to the present invention is that the air pressure on the air intake side is higher than the air pressure on the air discharge side, and the air pressure on the air discharge side is higher than the atmospheric pressure. It is set. The air intake is connected to the air supply means via the air supply passage.

A feature of the fixing device according to the present invention is that a blower fan or a pulsating flow pump is used as the air supply means.
Particularly, when a pulsating flow pump is used, it is characterized in that the air supply by the pulsating flow pump is interlocked with the opening / closing operation of a predetermined member. The air supply passage may be a single passage or may have any form branching on the way to the air intake. When the air supply passage is branched, it is preferable because it can be connected to one branched air intake and the other air supply passage can be used as a cooling passage for another member.

A feature of the fixing device according to the present invention is that the non-contact temperature detecting means has a control board and is positioned on the holder by locking the control board by an engaging member formed on the holder. . It is preferable that the engaging member is an elastically deformable member because the non-contact temperature detecting means and the holder can be easily attached and detached. Considering the heat resistance of the non-contact temperature detecting means, it is preferable to use a heat resistant resin for the holder. Examples of the fixing rotator include a roller member and an endless belt member wound around a plurality of rollers.

In the image forming apparatus according to the present invention, the electrostatic latent image formed on the image carrier is visualized as a toner image by the developing means, the toner image is transferred to the recording material, and then the recording material is transferred. The fixing is performed through the fixing device, and any one of the fixing devices having the above characteristics is used as the fixing device.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The same configurations as those of the conventional technique are denoted by the same reference numerals, and the description of the configurations and the functions already performed will be omitted unless particularly necessary. FIG. 5 shows a schematic configuration of a printer as an image forming apparatus. The printer is the paper feeding device 10
4, a registration roller pair 106, a photosensitive drum 108 as an image carrier, a transfer unit 110, a fixing unit 30 as a fixing device, and the like.

The sheet feeding device 104 includes a sheet feeding tray 114 for accommodating sheets 136 in a stacked state, a sheet feeding roller 116 for feeding the sheets 136 accommodated in the sheet feeding tray 114 in order from the top, and a separating member. It is equipped with 117 etc. The paper 136 delivered by the paper feed roller 116 is temporarily stopped by the registration roller pair 106, and after the skew displacement is corrected, it is formed at the timing synchronized with the rotation of the photoconductor drum 108, that is, on the photoconductor drum 108. The toner image is sent to the transfer portion N by the registration roller pair 106 at the timing when the front end of the toner image and the predetermined position of the front end of the paper 136 in the conveyance direction coincide with each other.

Around the photosensitive drum 108, a charging roller 118 as a charging means is arranged in the order of rotation directions indicated by arrows.
And a mirror 120 that constitutes a part of an exposing unit (not shown).
A developing unit 122 having a developing roller 122a, a transfer unit 110, a cleaning unit 124 having a cleaning blade 124a, and the like are arranged. The mirror 12 is provided between the charging roller 118 and the developing means 122.
The exposure unit 126 on the photoconductor drum 108 is irradiated with the exposure light 103 via 0, and scanning is performed.

The image forming operation in the printer is performed in the same manner as the conventional one. When the photoconductor drum 108 starts rotating, the surface of the photoconductor drum 108 is uniformly charged by the charging roller 118, and the exposure light 103 is applied to the exposure unit 126 based on the image information and scanned to correspond to the image to be created. Electrostatic latent image is formed. This electrostatic latent image is moved to the developing means 122 by the rotation of the photosensitive drum 108, and toner is supplied by the developing roller 122a to be visualized,
A toner image is formed. The toner image formed on the photosensitive drum 108 is transferred onto the paper 136 that has entered the transfer portion N at a predetermined timing by applying a transfer bias by the transfer unit 110. The sheet 136 carrying the toner image is conveyed toward the fixing unit 30, fixed by the fixing unit 30, and then discharged and stacked on a sheet discharge tray (not shown).

The photosensitive drum 1 without being transferred at the transfer portion N
The residual toner remaining on the toner 08 reaches the cleaning unit 124 as the photosensitive drum 108 rotates, and while passing through the cleaning unit 124, it is scraped off and cleaned by the cleaning blade 124a. After that, the residual potential on the photoconductor drum 108 is removed by a discharging unit (not shown), and the apparatus is prepared for the next image forming step.

The structure of the fixing unit 30 will be described. The fixing unit 30 of the present embodiment has a heating roller 2 that is heated by a halogen heater 3 as a fixing rotator and a pressure roller 4 that is in pressure contact with the heating roller 2 so as to face the heating roller 2 and the pressure roller 2. It is a well-known one in which the sheet 136 carrying an unfixed toner image is passed through the nip portion 4 to fix the sheet by heat and pressure.

The periphery of the heating roller 2 is covered with an upper cover 31, and the periphery of the pressure roller 4 is covered with a lower cover 41. In the vicinity of the upper cover 31, a temperature detection unit 20 having a thermopile 1 as a non-contact temperature detection means and an infrared sensor is arranged.

As shown in FIG. 1, the temperature detecting unit 20
Is composed of a thermopile 1 and a control board 22. In the present embodiment, in order to avoid the influence of heat and the adherence of suspended solids, the temperature detection unit 20 is arranged so as to detect it not obliquely above the heating roller 2 but obliquely above it. The can case 6 of the thermopile 1 is made of metal and has a tubular shape. A stainless steel material is used for the material of the can case 6. The control board 22 is provided on the base end side of the can case 6.
Are connected. A cable 23 for detection output (Vout) and power supply is connected to the control board 22. The cable 23 is connected to control means (not shown). Notches 53 and 54 that serve as locking portions are formed at the side edges of the control board 22 that face each other.

The fixing unit 30 has a holder 24 which is mounted on the thermopile 1 from the outside. The holder 24 is formed of a heat resistant resin having a softening point of 100 ° C. or higher. The holder 24 has a flat mounting surface 24a,
A cylindrical sensor protection portion 24 having a direct positional relationship with this.
0 and a holder mounting surface 28. Mounting surface 24a
At the same time, the can case 6 is inserted into the sensor protection portion 240, and an opening portion 25 is formed as a holding portion for holding the thermopile 1 by fitting the can case 6 with the outer periphery of the can case 6 without a gap during mounting. . At positions corresponding to the notches 53, 54, claw portions 51, 52 are formed as engaging members that are elastically deformable in the direction in which the notches 53, 54 move forward and backward. Each claw portion has a size that can be inserted into the cutouts 53 and 54, and when inserted into the cutouts 53 and 54, the top surface 56 of the control board 22 and the mounting surface 24a.
Pressing parts 55 for pressing down are respectively formed.
The claws 51, 52 and the notches 53, 54 have substantially the same width, and when the temperature detecting unit 20 is mounted on the holder 24, the side faces of the claws 51, 52 have the notches 53, 54.
Positioning in the X direction is performed by the side surfaces 57 and 58 of the.

The holder mounting surface 28 has a plurality of screws 20.
.. through holes 28a .. A detection opening 32 for exposing the thermopile 1 to the heating roller 2 is formed in a portion of the upper cover 31 facing the incident surface 1a. A plurality of screw holes 32 a for mounting the bracket 29 for mounting the holder are provided in the vicinity of the detection opening 32.
.. is formed. Bracket 29 with L-shaped cross section
Are formed with screw holes 29a ... For the screw 201 at positions facing the insertion holes 28a ... And through holes 29b ... At positions corresponding to the screw holes 32a.

As shown in FIG. 3, the holder 24 having the temperature detecting unit 20 mounted thereon is attached to the bracket 29 with screws 2
It is fastened with 01 ..
By attaching to the upper cover 31 in the vicinity of the detection opening 32, the sensor protection portion 240 is arranged to face the detection opening 32.

As shown in FIG. 3, when the thermopile 1 and the holder 24 are in the mounted state, between the outer surface 6a of the can case 6 and the inner surface 240b of the sensor protection portion 240,
The space 32 is formed. The space 32 is formed so as to surround the entire outer surface 6 a of the can case 6. In the present embodiment, the inner surface 240b of the sensor protection portion 240 of the holder 24 is recessed to form the space portion 32.
The outer surface 6a side of the can case 6 is recessed, and the inner surface 2
The space portion 32 may be formed by recessing both 40b and the outer surface 6a.

An opening 243 is formed in the end face 240a of the sensor protection portion 240 located on the side of the incident surface 1a which is the temperature detecting surface of the thermopile 1. Sensor protector 24
0 communicates with the space 32 as shown in FIGS.
An air intake 241, which receives air supply, a plurality of ribs 242 supporting the incident surface 1a on the end face 240a, and the incident surface 1a.
An air discharge port 24a that communicates with the space 32 on the side is formed. The thermopile 1 has a rib 242 on the incident surface 1a.
The position of the holder 24 in the insertion direction is regulated by hitting against, and the retracted position from the holder 24 is regulated by the opening 25, so that the distance from the heating roller 2 in the arrow Y direction becomes constant. To be kept.

In the present embodiment, the air outlet 24a extends in the axial direction of the thermopile 1 and is formed so as to penetrate the holder 24 on the side of the incident surface 1a so that the air is guided to the incident surface 1a. Is configured.

One end of a tube 27 forming an air supply passage is connected to the air intake 241 via a plug member 26. The plug member 26 has a hollow shape, and one end of the plug member 26 is press-fitted into the air intake port 241 so that the holder 2
It is integrated with 4. The tube 27 is press-fitted into the other end of the plug member 26. The tube 27 is a flexible heat resistant tube, and for example, a silicon tube is used. The material of the tube 27 is not limited to silicon.

The other end of the tube 27 is, as shown in FIG. 6, the casing 3 of the blower fan 35 serving as an air supply means.
6 is connected to the tip 37. As shown in FIGS. 6 and 7, the blower fan 35 includes a casing 36 and a plurality of screws 20.
It is detachably attached at 4. Casing 36
Is the mounting hole 3 formed in the exterior cover 39 of the printer.
It is inserted into 9a and is detachably attached with a plurality of screws 203. Although the portion of the fan 35 exposed to the outside of the device is omitted in FIGS. 6 and 7, a fan cover, an air filter, and the like are provided, and safety measures are taken.

The air intake 241 and the air exhaust 24a are
The air pressure on the air supply port 241 side is equal to the air discharge port 24a.
Is higher than the air pressure on the side, and the air pressure on the side of the air outlet 24a is set to be higher than the atmospheric pressure.

In the fixing unit 30 having such a structure, when the power of the printer is turned on, the surface of the heating roller 2 is heated to a high temperature of about 180 ° C. by the heat generation effect of the halogen heater 3 and the fan 35 is heated. A drive motor (not shown) is driven to rotate the fan, and the air outside the machine is supplied to the space 32 through the tube 27.
When the supplied air enters the holder 24, the can case 6
Since the air trunk portion 32 is formed around the entire circumference, air flows along the outer surface 6a of the can case 6. Since the case 6 and the opening 25 are fitted together without a gap, the air flows toward the air discharge port 24a and is discharged to the outside of the holder 24.

Therefore, the temperature rise of the can case 6 and the holder 24 due to the radiant heat from the heating roller 2 can be suppressed by the cooling action of the supplied air, the durability of the thermopile 1 can be improved, and the service can be improved. It is possible to prevent a rapid temperature change of the mopile 1, perform highly accurate temperature control, and prevent damage to the element due to high temperature. Further, since the air supplied to the space 32 is discharged from the air discharge port 24a, a shielding layer by the air, that is, an air curtain is formed on the incident surface 1a side, so the filter 8 of the thermopile 1 and the like. It is possible to prevent floating substances floating in the equipment from adhering, and to perform accurate temperature detection.

Since the holder 24 covers the can case 6 except for the incident surface 1a (filter 8), dirt is prevented from adhering to the can case 6 while suppressing a rapid temperature rise of the can case 6. I can do it. In the present embodiment, as shown in FIG. 4, the rib 242 and the air discharge port 24a.
Although four and four are set respectively, the number is not limited to the illustrated number.

In this embodiment, as shown in FIG. 1, the method of fixing the temperature detecting unit 20 and the holder 24 is based on the claw portion 5.
Positioning and fixing are performed by inserting the notches 1, 52 into the notches 53, 54, so that the positioning in the X direction and the Y direction can be performed easily, the distance between the thermopile 1 and the heating roller 2 becomes stable, and the detection position It is possible to reduce variations in output due to differences in
More stable control of the fixing temperature can be performed. Furthermore, the claw portion 5
By expanding 1, 52 in the direction of the arrow, the engagement with the notches 53, 54 can be easily released, so that the unit can be easily replaced.

8 and 9 show another form of the air outlet 34. The air outlet 34 is provided in the space 32.
And is bent so that its tip is substantially parallel to the incident surface 1a. Therefore, tube 2
7. The air that has passed through the space 32 is ejected so as to block the filter 8. Therefore, the shielding layer (air curtain) formed by the air prevents the adherence of suspended matter in the device more than the air outlet 24a. can do. Also in this embodiment, the number of the ribs 242 serving as the abutting portions of the can case 6 is four, but the number is not limited to this. The pressure of the air supplied from the tube 27 may be very small, and if the air pressure is slightly higher than the outlet pressure (atmospheric pressure), even a minute amount of air has a sufficient anti-adhesion effect.

In FIG. 10, the air supply passage communicating with the fan 35 is branched so that the tube 27 serves as an air supply passage.
Two routes are formed by a and 27b. In this embodiment, the tip end 370 of the casing 36 is connected to the two opening portions 4.
0 and 41, and the tubes 27a and 27b are connected to the opening 40 and the opening 41, respectively. In the present embodiment, the tube 27a is piped to the air intake port 241, and the tube 27b is, for example, the fixing unit 30.
The casings 31 and 32, the developing unit 122, and the like are connected. In this way, one fan 35 can cool the thermopile 1 and a plurality of parts other than this at the same time, and the inside of the device can be efficiently cooled.

FIG. 11 uses a pulsating flow pump 42 as an air supply means. The pulsating flow pump 42 includes a bellows portion 42a that is expandable and contractible, and holding portions 42a and 43a that hold both ends of the bellows 42a. Holding part 4
The tube 27 is connected to the 2a side, and the on-off valve 46 is built therein. The holding portion 43a is formed at one end of the rod 43 which is slidably supported by the supporting portion 60 in the arrow direction. The other end 43b of the rod is connected to an open / close cover (not shown) of the printer.

The holding portion 43a is formed with an air passage 45 which connects the inside and outside of the bellows 42a. An opening / closing valve 46 for opening / closing the air passage 45 is built in the bellows 42a from the holding portion 43a.

In this embodiment, when the main body cover of the printer is manually opened, the rod 43 slides in conjunction with each other,
The bellows 42a is crushed and the internal air pushes the on-off valve 46 to supply the air to the tube 27. The supplied air is discharged from the air discharge port 24a to the outside of the holder 24 through the space 32. Crushed bellows 42a
Returns with a restoring force, and at that time, air is pushed away from the on-off valve 47 from the air passage 45 and is taken into the inside of the bellows 42a. Polyethylene was used as the material of the bellows 42a. The wall thickness is as thin as about 0.2 mm.

Examples of the opening / closing operation of the opening / closing cover (not shown) include opening / closing of the pressure plate when setting the ADF sheet, and opening / closing of the opening / closing cover during jamming and maintenance. By supplying air by the pulsating flow pump 42 in conjunction with opening / closing operations of various opening / closing covers provided in such a printer, air can be regularly discharged from the air discharge port 24a. Floating matter adhering to can be removed by jetting air. In this embodiment, the collapsed bellows 42a is returned by the restoring force of the bellows 42a, but if the returning action is weak, a return spring may be added.

In the above-described embodiment, the fixing device is a roller fixing system using the heating roller 2 and the pressure roller 3, and the thermopile 1 detects the radiant heat (infrared ray) from the heating roller 2 serving as a fixing rotating member. However, the measurement target is not limited to such a roller member. For example, like the fixing device 300 shown in FIG. 12, as the fixing rotating member, the roller 301 and the roller 3 which are heated by the heater 305 are used.
When the fixing belt 303 as a belt member wound around the belt 02 is used, the fixing belt 303 is used as a measurement target, and the radiant heat (infrared ray) from the belt is detected by the thermopile 1. Good. As the type of the roller 301 and the belt 303, a soft roller or a belt having a silicon rubber layer formed on the surface of the metal roller or the belt is not the currently used mainstream hard roller (Teflon (registered trademark) coating on the surface of the metal roller). Can be mentioned. In this case, in the contact-type temperature detecting means, the surface of the roller or belt to be detected is easily scratched because of rubber, but if the non-contact temperature detecting means like the present invention is used, such a problem will occur. No more worrying about the improvement of the durability of Thermopile 1,
The temperature of the thermopile 1 can be controlled with high accuracy by preventing abrupt temperature change, damage of the element due to high temperature can be prevented, and floating substances floating in the equipment can be attached to the filter 8 of the thermopile 1. It is possible to provide a belt-fixing type fixing device and an image forming apparatus that can prevent the temperature and perform accurate temperature detection.

In each of the above embodiments, the air inlet 241 and the air outlet 24a or the air outlet 34 are communicated with the space 32, and air is forcibly supplied using various pumps. It may be in the form without various pumps. In this case, the air in the space 32 is introduced into the space 32 through the air intake 241 and the air outlet 24a by natural convection. Air intake 241
Without the air outlet 24a or the air outlet 34,
In the case where the space 32 is simply formed between the outer surface 6a of the can case 6 and the inner surface 24 of the holder 24, cooling or removal of adhering substances due to air flow cannot be expected, but the air in the space 32 is a heat insulating layer. Therefore, it is possible to prevent a rapid temperature change of the thermopile 1 and to perform highly accurate temperature control and prevent damage to the element due to a high temperature, as compared with the structure without the space portion 32.

[0046]

EFFECTS OF THE INVENTION According to the present invention, the heat resistance of the non-contact temperature detecting means capable of accurately detecting a thermal change due to the heat insulating effect on the air layer in the space and the cooling effect of the air supplied to the space and flowing. It is possible to improve the durability, improve the temperature control with high accuracy, stabilize the fixing temperature of the fixing member, and improve the fixing property. According to the present invention, since the air shielding layer is formed by the air discharged from the air outlet, it becomes difficult for the suspended matter to adhere to the detection surface, and the discharged air adheres to the detection surface. Is removed, so that accurate temperature control can be performed.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing a configuration of a non-contact temperature detecting means, a holder and its periphery.

FIG. 2 is a partially cutaway enlarged view showing a tip configuration of a holder.

FIG. 3 is an enlarged cross-sectional view showing an internal configuration of a holder, a mounting state of a non-contact temperature detecting means, and an air supply path.

FIG. 4 shows a holder equipped with a non-contact temperature detecting means,
It is an enlarged view seen from the fixing rotating body side.

FIG. 5 is a schematic configuration diagram of an image forming apparatus including a fixing device according to the present invention.

FIG. 6 is an enlarged cross-sectional view showing configurations of an air supply unit and an air supply passage.

FIG. 7 is a front view of a fan that is one form of air supply means.

FIG. 8 is an enlarged cross-sectional view showing an internal configuration of a holder having another form of an air discharge port, a mounting state of a non-contact temperature detecting means, and an air supply path.

FIG. 9 shows a holder equipped with a non-contact temperature detecting means,
It is an enlarged view seen from the fixing rotating body side.

FIG. 10 is an enlarged cross-sectional view showing the configuration of a branched air supply passage.

FIG. 11 is an enlarged cross-sectional view showing a configuration example of a pulsation pump which is another form of air supply means.

FIG. 12 is an enlarged cross-sectional view showing the configuration of a belt fixing type fixing device to which the present invention is applied.

FIG. 13 is a schematic configuration diagram of a fixing device.

FIG. 14A is a perspective view showing a structure of a thermopile,
(B) is sectional drawing of a thermopile.

[Explanation of symbols]

1 Non-contact temperature detection means 1a Temperature detection surface 2,303 fixing rotating body 3,305 heating means 4,304 Pressurizing means 6a Outer surface of non-contact temperature detecting means 22 Control board 24 holder 24a, 34 Air outlet 240b Inner surface of holder 25 Holder 30,300 fixing device 32 space 241 air intake 242 multiple ribs 27, 27a, 27b Air supply passage 35,42 Air supply means 51,52 engaging member 108 image carrier 122 developing means 136 recording material

Claims (15)

[Claims] 1. A fixing rotating body heated by a heating means, a non-contact temperature detecting means provided in a non-contact state with the fixing rotating body, for detecting heat radiated from the fixing rotating body, A fixing device for controlling the temperature of the fixing rotator on the basis of the detection result of the non-contact temperature detecting means, the non-contact temperature detecting means having a holder mounted from outside, and the non-contact temperature detecting means and the holder. At least one of the outer surface of the non-contact temperature detecting means or the inner surface of the holder so that a space is formed between the outer surface of the non-contact temperature detecting means and the inner surface of the holder when and are mounted. The fixing device is characterized in that. 2. The fixing device according to claim 1, wherein the space portion is formed so as to surround an outer surface of the non-contact temperature detecting means. 3. The fixing device according to claim 1, wherein the holder has a holding portion for holding the non-contact temperature detecting means. 4. The fixing device according to claim 1, 2 or 3, wherein the holder is provided with an air inlet communicating with the space and supplied with air. 5. The fixing device according to claim 4, wherein the holder includes a plurality of ribs that support the non-contact temperature detecting means on the temperature detection surface side of the non-contact temperature detecting means.
The fixing device is characterized in that an air outlet communicating with the space is formed on the temperature detection surface side. 6. The fixing device according to claim 5, wherein the air discharge port is formed so that air is guided to the temperature detection surface. 7. The fixing device according to claim 5, wherein the air pressure on the air intake side is higher than the air pressure on the air exhaust side, and the air pressure on the air exhaust side is A fixing device characterized by being set to be higher than atmospheric pressure. 8. The fixing device according to claim 4, 5, 6 or 7, wherein the air intake port is connected to an air supply means through an air supply passage. 9. The fixing device according to claim 8, wherein the air supply unit is a blower fan. 10. The fixing device according to claim 8, wherein the air supply unit is a pulsating flow pump, and the air supply by the pulsating flow pump is interlocked with the opening / closing operation of a predetermined member. apparatus. 11. The fixing device according to claim 8, 9 or 10, wherein the air supply passage is branched. 12. The fixing device according to claim 1, wherein the non-contact temperature detecting means has a control board, and the control board is engaged by an engagement member formed on the holder. The fixing device is positioned on the holder by stopping. 13. The fixing device according to claim 1, wherein the holder is made of heat resistant resin. 14. The fixing device according to claim 1, wherein the fixing rotator is a roller or a belt stretched around a plurality of rollers. 15. An electrostatic latent image formed on an image carrier is visualized as a toner image by developing means, the toner image is transferred onto a recording material, and the recording material is passed through a fixing device to be fixed. An image forming apparatus for performing the above, wherein the fixing device is the fixing device according to any one of claims 1 to 14.