JP2006220977A - Temperature detecting device, temperature control means and fixing device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature detecting device and a temperature control means capable of appropriately correcting a detection error caused by the staining of the surface of a non-contact temperature detection means. <P>SOLUTION: The temperature detecting device has an infrared temperature detection means as a first temperature detection means capable of detecting temperature at least at two or more spots from one aperture, and has a second temperature detection means near at least one spot out of the spots where the temperature is detected by the infrared temperature detection means or a spot where temperature estimated as nearly the same temperature as that at the one spot is detected. The temperature control means has a heating source and a member to be heated which is heated by the heating source, and controls the temperature of the member to be heated by using the temperature detected by the second temperature detection means as defined in the claim 1 and the infrared temperature detection means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a temperature detection device that detects a surface temperature of a heated member heated by a heating source. In particular, the present invention relates to an improvement in infrared temperature detecting means for detecting infrared rays.

  Conventionally, in an image forming apparatus such as a copying machine, a thermistor has been widely used as a temperature detecting means used in a fixing device. However, since the thermistor detects the temperature by contacting a fixing roller as a fixing unit, it has a problem that an image defect occurs due to wear or damage of the fixing roller.

  As the non-contact type temperature detecting means, an infrared sensor such as a thermopile is representative. Since the infrared sensor detects the temperature of the object to be measured from the amount of infrared rays radiated according to the object temperature, temperature detection by non-contact is possible.

  In addition, a non-contact type fixing device that measures a plurality of locations with one temperature sensor has already been proposed (for example, see Patent Document 1).

JP 2003-066761 A JP-A-5-149790

  However, if dirt is attached to the surface of the infrared sensor, the output of the infrared sensor is reduced and a temperature lower than the actual temperature is detected. Therefore, in the image forming apparatus, the temperature of the fixing roller is increased more than necessary. There is a possibility.

  In addition, it is possible to prevent the occurrence of image defects by bringing a thermistor into contact with the non-image forming unit and performing temperature measurement. However, there is a temperature difference between the non-image forming unit and the image forming unit, and the accurate temperature It is difficult to control.

  As a means for solving this problem, for example, in addition to the infrared sensor, a thermistor which is a contact-type temperature detecting means is provided, and the thermistor is brought into contact with the fixing roller periodically to thereby use both the infrared sensor and the thermistor. Means for correcting the detected temperature difference of the fixing roller, that is, correcting output decrease due to contamination of the infrared sensor has been proposed (for example, see Patent Document 2).

  However, this means necessitates a drive mechanism for detaching the thermistor from the fixing roller, which complicates the configuration. In addition, there is a need for improvement as a cause of erroneous temperature detection due to the thermistor floating.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a temperature detection device, a temperature control means, and a fixing device using the temperature detection device that can appropriately correct a detection error caused by contamination on the surface of the non-contact temperature detection means.

  In order to achieve the above object, the temperature detection device according to claim 1 has infrared temperature detection means as first temperature detection means capable of detecting at least two or more temperatures from one opening, and the infrared temperature detection means. Of the locations detected by the means, the second temperature detection means is provided in the vicinity of at least one location or a location estimated to be substantially the same temperature.

  The temperature control means according to claim 2 has a heating source and a member to be heated that is heated by the heating source, and uses the temperature detected by the second temperature detection means and the infrared temperature detection means according to claim 1. The temperature of the member to be heated is controlled.

  According to a third aspect of the present invention, there is provided a heating source, a heated member heated by the heating source, a pressure member disposed to face the heated member, the heated member, and the pressure member. Infrared temperature detection as a first temperature detecting means capable of detecting at least two temperatures of the member to be heated from one opening in a fixing device that nipping and conveying and fixing an unfixed toner image on a recording material And a second temperature detection means provided in the vicinity of at least one of the locations detected by the infrared temperature detection means or a location estimated to be substantially the same temperature, and the first temperature detection means It has a temperature control means for controlling the temperature of the member to be heated using the value detected by the infrared detecting means and the value detected by the second temperature detecting means.

  According to a fourth aspect of the present invention, in the third aspect of the invention, at least one of the detection portions of the first temperature detection means is within a minimum size sheet passing area in the heated member axial direction, and the second temperature detection is performed. The detection location of the means is outside the maximum size sheet passing area in the axial direction of the heated member.

  The invention according to claim 5 is the invention according to claim 3, wherein the member to be heated is a rotating body, and one of the detection points of the first temperature detection unit and the detection point of the second temperature detection unit are The heating member has substantially the same circumference and substantially the same height.

  According to a sixth aspect of the present invention, in the invention according to the third aspect, the heating means has a first heat generation amount near the center in a direction orthogonal to the recording material conveyance direction of the heating member larger than a heat generation amount near the end portion. A heating unit and a second heating unit having a heat generation amount near the end of the heating member in a direction orthogonal to the recording material conveyance direction being larger than a heat generation amount near the center. At least one of the first heating means near the center of the heated member is a portion corresponding to a large amount of heat generated, and at least one of the detection points of the first temperature detecting means is the first portion near the end of the heated member. 2 is a portion corresponding to a portion of the heating unit that generates a large amount of heat, and the detection portion of the second temperature detection unit is outside the maximum size sheet passing region in the heated member axial direction.

  According to the first aspect of the present invention, since the first temperature detecting means is non-contact, measurement can be performed without damaging the object to be measured. In order to detect the point to be measured on the object to be measured) and the calibration point (the part having the same temperature as that of the second temperature detecting means), even when dirt such as toner adheres to the opening surface, By comparing and correcting the detection value of the temperature detection means and the second temperature detection means, an accurate value can be measured without being affected by dirt.

  The temperature control means according to claim 2 can control the member to be heated at a more accurate temperature without being affected by the contamination of the first temperature detection means, similarly to the invention according to claim 1.

  According to the third aspect of the present invention, since the heated member can be controlled at an accurate temperature without being affected by the contamination of the first temperature detecting means, the fixing device free from image defects due to erroneous temperature detection or the like. Can be provided.

  According to the fourth aspect of the invention, by arranging the second temperature detecting means in the non-sheet passing area, for example, a contact type thermistor can be used, so that more accurate temperature correction can be performed. As a result, the first temperature detection means can control the temperature of the heated member more accurately in the sheet passing area, and can provide a fixing device free from image defects due to erroneous temperature detection or the like.

  According to the fifth aspect of the present invention, even when there is no space for disposing the second temperature detection means in the vicinity of the detection location of the first temperature detection means, if the above configuration is adopted, heat convection or the like may occur. The temperature of the object to be heated is less affected by the temperature distribution, and the temperature at one of the detection points of the first temperature detection means and the detection point of the second temperature detection means can be regarded as substantially the same temperature. This makes it possible to provide a fixing device free from image defects due to erroneous temperature detection or the like.

  According to the sixth aspect of the present invention, since only one temperature correction circuit is used as compared with the case where the infrared sensor unit is used for controlling each of the middle-high heater and the end-high heater, the temperature in the axial direction can be reduced with a simple configuration. There is little unevenness, and it is possible to prevent image defects caused by erroneous detection due to dirt.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
[Outline of image forming apparatus]
FIG. 1 shows an embodiment of an image forming apparatus as a digital copying machine provided with a fixing device having a temperature detecting device according to the present invention.

  The image forming apparatus according to the present embodiment includes a reader unit 1 in the upper part of the apparatus body and a printer unit 2 in the lower part.

  The reader unit 1 includes a document table 11 on which a document is placed, a document pressure plate 12 that presses the placed document from above, a light source 13 that irradiates an image surface of the document, and a plurality of mirrors that guide reflected light from the image surface. 14, the lens 15, and reflected light are subjected to photoelectric conversion by a CCD, and an image processing unit 16 that performs various image processing on the obtained electric signal is a main constituent member.

  The image processing unit 16 has image processing functions such as a CCD (not shown), A / D conversion, S / H, shading correction, masking correction, scaling, and LOG conversion.

  The operation of the reader unit 1 configured as described above is as follows.

  A document is placed on the document table 11 so that the image surface faces downward, and is pressed by the document pressure plate 12 from above. The light source 13 moves in the direction of the arrow K1 while irradiating light, and scans the image surface of the document. The reflected light image from the image plane is formed on the CCD via a plurality of mirrors 14 and lenses 15 and is photoelectrically converted into electric signals here. The image signal that has become an electrical signal is subjected to various image processing in the image processing unit 16 and then sent to the next printer unit 2.

  As shown in FIG. 1, the printer unit 2 converts the electric signal sent from the reader unit 1 into a signal for driving the laser element 18 and the surface of the photosensitive drum 30 with the laser beam L. The main components are a polygon scanner 19 that scans the image and forms an electrostatic latent image, an image forming unit 3 including a photosensitive drum 30, and a fixing unit (fixing device) 39 disposed on the most downstream side.

  Further, the image forming unit 3 described above is a primary drum that is uniformly charged on the surface of the photosensitive drum 30 that is rotatably supported in the direction of the arrow and that is disposed around the photosensitive drum 30 approximately in the rotational direction. The charger 31, the developing device 20 that develops the electrostatic latent image formed on the photosensitive drum 30 as a toner image, the transfer charger 35 that transfers the toner image on the photosensitive drum 30 to the transfer material P, and the transfer of the photosensitive drum 30 A cleaner 34 that removes residual toner, an auxiliary charger 33 that performs charge removal, and a pre-exposure lamp 32 that removes remaining charge are provided.

  The developing device 20 has a developing roller 20a disposed opposite to the photosensitive drum 30, and the developing roller 20a rotates in the opposite direction to the photosensitive drum 30, thereby developing the electrostatic latent image on the photosensitive drum 30 as a toner image. .

  The toner image on the photosensitive drum 30 is transferred to the transfer material P by the transfer charger 35, and the transfer material P to which the toner image is transferred is conveyed to the fixing unit 39 by the pre-fixing belt 37. In the fixing unit 39, fixing rollers 39a and 39b as fixing means are rotated to convey the transfer material P and pressurized, and the toner image on the surface is fixed by receiving heat and pressure. After the fixing, the transfer material P is discharged onto the tray 41 outside the apparatus main body.

  A feeding / conveying section that feeds and conveys the transfer material P has a conveyance path for the transfer material P, and is provided with a sheet feeding cassette 36, a sheet feeding roller 36a, and a conveyance roller 36b on the most upstream side in the conveyance direction of the transfer material P. And a sheet feeding device having the above.

In addition to the paper feeding device, a multi paper feeding device 38 is provided. Since the paper feeding path is straight from the multi-sheet feeding device 38, various transfer materials P having different properties such as material and size can be supplied to the image forming unit 3.
[Basic configuration and operation for image formation]
Next, a basic configuration and operation relating to image formation will be described with reference to FIGS.

  The system controller 71 performs various controls of the image forming apparatus, and performs overall control by an internal CPU 71a. For example, the image input unit 72, the image processing unit 16, the fixing unit 39, and the like that constitute a part of the reader unit 1 are controlled. Based on the image data obtained by the image processing unit, the laser driving circuit 17 modulates and drives the semiconductor laser 18.

  Further, an electrostatic latent image is formed on the surface of the photosensitive drum 30 by the output light of the semiconductor laser 18. The electrostatic latent image is developed as a toner image by the developing device 20 and then transferred to the transfer material P by the transfer charger 35.

  Further, the fixing unit 39 includes a fixing roller 39a, a pressure roller 39b, a fixing roller temperature sensor 39c which is a non-contact temperature detecting means, and a non-sheet-passing portion contact thermistor 39d, and a toner image transferred onto the transfer material P. Is fixed to the transfer material P by heating and pressing.

  Next, temperature control of the fixing roller 39a in the fixing unit 39 will be described with reference to FIG.

  In this apparatus, in order to measure the temperature of the fixing roller 39a, an infrared sensor unit 39c that measures infrared rays emitted from the fixing roller 39a and measures the temperature from the amount of received infrared rays is used. As described above, a thermistor has been widely used as a temperature detection means for the fixing roller. However, in order to bring the thermistor into contact with the fixing roller, the fixing roller is worn or thermistor is worn or damaged. There was a problem of erroneous temperature detection due to floating from the fixing roller. Therefore, this apparatus employs a non-contact infrared temperature sensor unit 39c.

  The temperature detection signal of the fixing roller 39a detected by the infrared sensor unit 39c is input to the system controller 71 via the A / D converter 211.

  A halogen heater is used as the fixing heater 208 as a heating body for heating the fixing roller 39a. The fixing heater 208 is controlled to be turned on / off by the control signal from the system controller 71 via the heater control unit 210. Since the halogen heater 208 is AC driven, the heater control unit 210 incorporates an SSR therein and turns on / off the AC power supply for heater supply based on a control command from the system controller 71.

  The system controller 71 converts the input temperature detection signal of the fixing roller 39a from the infrared sensor unit 39c into a fixing roller temperature, and based on this temperature, the heater controller 210 adjusts the fixing roller 39a to a specified temperature. The temperature is controlled by turning the fixing heater on and off in a unified manner.

  Here, if toner or silicon mist scattered in the apparatus adheres to the surface of the infrared sensor unit 39c, that is, the infrared light receiving part, the infrared ray in that part is cut off, so that the output of the temperature detection signal is reduced. As a result, the system controller 71 receives a temperature detection signal at a level lower than the original temperature detection signal.

In the system controller 71, since the temperature detection signal lower than the original is determined as the temperature lower than the original, actually, although the fixing roller 39a is at the target temperature, a process for further increasing the temperature is performed. End up. In the worst case, the fixing roller 39a is also damaged.
[Infrared sensor unit]
The infrared sensor unit 39c in the present embodiment will be described in detail.

  FIG. 7 is a cross-sectional view of the infrared sensor unit 39c. The infrared sensor unit 39c includes infrared detection elements S1 and S2, an opening O, a lens L, and the like. By converting the heat radiation energy emitted from the fixing roller 39a incident through the opening O into an electric signal by the infrared detection elements S1 and S2, the temperature of the fixing roller 39a can be detected. As the infrared detection elements S1 and S2, for example, a thermopile, a pyroelectric element, or the like can be used.

As shown in FIG. 7, the infrared sensor unit 39c in the present embodiment has a plurality of infrared detection elements S1 and S2, and can measure a plurality of locations with one infrared sensor unit 39c. Yes. At this time, in order to reduce the influence of uneven dirt on the surface of the lens L in the opening O, the optical paths x1 and x2 of the infrared rays emitted from the object to be measured incident on the infrared detection elements S1 and S2 as shown in FIG. It is desirable to pass through substantially the same location on the surface.
[Longitudinal configuration]
In the configuration of the present embodiment, as shown in FIG. 4, the contact thermistor 39d as the second temperature detecting means is in contact with the non-sheet passing portion of the fixing roller 39a. The infrared sensor unit 39c as the first temperature detecting means is configured to detect the temperatures of the fixing roller 39a central portion a and the thermistor vicinity b of the non-sheet passing portion. At this time, there is no problem even if the non-sheet passing portion thermistor 39d also serves as an excessive temperature rise detection due to the temperature rise of the non-sheet passing portion during continuous feeding.
[Temperature detection signal error correction control]
Next, correction control of an error in the temperature detection signal due to contamination on the surface of the infrared sensor unit will be described with reference to FIGS.

  First, the temperature in the vicinity (detection position b) of the non-sheet passing portion contact thermistor 39d is detected by the infrared sensor unit 39c. The temperature detection signal at the detection position b is input to the correction circuit 100. At the same time, the temperature detection signal of the non-sheet passing portion contact thermistor 39d is also input to the correction circuit 100.

  In the correction circuit 100, the temperature detection signal of the non-sheet passing portion contact thermistor 39d is temporarily input to the system controller 71 to calculate the temperature. The temperature detection signal Er of the infrared sensor unit 39c that should be originally obtained corresponding to the temperature is calculated. [V] is compared with the temperature detection signal Eb [V] of the actual infrared sensor unit 39c, and the difference E [V] is a correction value for correcting the signal, and this correction value E [V] The data is stored in the memory 103 (see FIG. 5) which is an internal storage unit.

  In the correction circuit 100, the correction value E [V] stored in the memory 103 is added to the temperature detection signal Ea [V] at the detection point a of the fixing roller 39a detected by the infrared sensor unit 39c. The detection value Eo [V] is output.

  Next, the operation of the correction circuit 100 will be described with reference to FIG.

  The correction circuit 100 includes a calculation circuit 102 as a calculation unit, a memory 103, and an addition circuit 104 as an addition unit.

  The detection signal of the detection position b of the infrared sensor unit 39 c and the detection signal of the non-sheet passing portion contact thermistor 39 d are input to the arithmetic circuit 102. A detection signal at the detection position a of the infrared sensor unit 39 c is input to the adder circuit 104.

  The temperature detection signal Ea from the infrared sensor unit 39c and the temperature detection signal Er from the non-sheet passing portion contact thermistor 39d are input to the arithmetic circuit 102. Here, the calculated correction value E is stored in the memory 103.

  The temperature detection signal Ea from the detection position a of the infrared sensor unit 39c is input to the addition circuit 104, where the correction value E stored in the memory 103 is added to the temperature detection signal Ea, and the infrared sensor unit 39c A corrected temperature detection value Eo (= Ea + E) in which the temperature detection signal Ea is corrected is output.

  Next, an algorithm related to this control will be described with reference to FIG.

  When the power source of the image forming apparatus is turned on (S0), first, a temperature detection signal at the measurement point b is detected by the infrared sensor unit 39c (S1). At the same time, a temperature detection signal is detected by the non-sheet passing portion contact thermistor 39d (S2). Both temperature detection signals are input to the correction circuit 100, and the internal correction circuit 102 corrects the temperature based on the temperature detection result from the non-sheet passing portion contact thermistor 39d and the temperature signal detection value at the measurement point b of the infrared sensor unit 39c. The value is calculated, and this correction value is stored in the memory 103 (S3).

  Next, the fixing roller 39a is monitored by the measurement point a of the infrared sensor unit 39c, and a temperature detection signal is detected (S4). The temperature detection signal is input to the correction circuit 100, and the internal addition circuit 104 adds the correction value stored in the memory 103 to the temperature detection signal, thereby correcting the temperature detection signal of the infrared sensor unit 39c. A value is output (S5).

  Next, the temperature adjustment of the fixing roller 39a is performed as follows.

  The fixing roller temperature Ta [° C.] is converted by the system controller 71 based on the corrected temperature detection value (S6). The fixing roller temperature Ta [° C.] is compared with the fixing roller temperature T [° C.] at which the fixing heater 208 is to be turned on (S7).

  When the fixing roller temperature Ta [° C.] is lower than T, the fixing heater 208 is turned on to heat the fixing roller 39a (S8).

  Here, when the fixing roller temperature Ta is higher than T, the fixing heater 208 is turned off (S9).

  As described above, according to the present embodiment, even when the surface of the infrared sensor unit 39c is soiled, it is brought into contact with the non-sheet passing portion of the fixing roller 39a through the infrared sensor unit opening O where the soil is attached. By detecting and correcting the temperature near the thermistor b and the temperature of the non-sheet passing portion contact thermistor 39d for calibration, the temperature of the surface of the fixing roller sheet passing area a can be accurately detected in a non-contact manner. Occurrence of image defects due to erroneous detection or the like can be prevented.

<Embodiment 2>
In the first embodiment, the non-sheet-passing portion contact thermistor 39d as the second temperature detecting means is disposed in the vicinity of the detection position b of the infrared sensor unit 39c. However, in the present embodiment, as shown in FIG. The paper portion contact thermistor 39d is configured to have the same height on the same circumference of the fixing roller 39a at the detection position b of the infrared sensor unit 39c.

  With this configuration, even when there is no space for arranging the non-sheet passing portion contact thermistor 39d for calibration in the non-sheet passing area in the vicinity of the detection position b of the infrared sensor unit 39c, if the above configuration is adopted, heat convection, etc. Thus, the temperature distribution of the heated object is small and the temperature of the detection position b of the infrared sensor unit 39c and the temperature of the non-sheet passing portion contact thermistor 39d for calibration can be regarded as substantially the same. It is possible to provide a fixing device free from image defects due to erroneous detection or the like.

<Embodiment 3>
In the present embodiment, as shown in FIG. 9, instead of the fixing heater 208 as the heating source of the first embodiment, a large amount of heat is generated in the central portion for small size in order to prevent the temperature increase in the non-sheet passing portion. The middle and high heaters 208a and the large size end part are composed of two end high heaters 208c that generate a large amount of heat. The light distribution characteristics of each heater at this time are shown in FIG.

  In addition, the measurement position of the infrared sensor unit 39c is the detection position a (the position corresponding to the high heat generation area of the middle / high heater 208a) in the fixing roller axial direction center, and the detection position c (end high heater) at the fixing roller axial end. 208c, the position corresponding to the high heat generation area 208c), the detection position b of the non-sheet passing portion through which the maximum size paper does not pass, and the second temperature detection in the vicinity of the detection position b of the non-sheet passing portion as in the first embodiment. A non-sheet passing portion contact thermistor 39d as a means is disposed.

  The detection values of the detection positions a and c of the infrared sensor unit 39c are both corrected from the difference between the detection value of the non-sheet passing portion detection position b of the infrared sensor unit 39c and the detection value of the non-sheet passing portion contact thermistor 39d. . Since the correction control is substantially the same as that of the first embodiment, description thereof will be omitted.

  Next, an algorithm related to this control will be described with reference to FIG.

  When the power of the image forming apparatus is turned on (S0 '), first, the temperature detection signal at the measurement point b is detected by the infrared sensor unit 39c (S1'). At the same time, a temperature detection signal is detected by the non-sheet passing portion contact thermistor 39d (S2 '). Both temperature detection signals are input to the correction circuit 100, and the internal correction circuit 102 corrects the temperature based on the temperature detection result from the non-sheet passing portion contact thermistor 39d and the temperature signal detection value at the measurement point b of the infrared sensor unit 39c. The value is calculated and this correction value is stored in the memory 103 (S3 ′).

  Next, the fixing roller 39a is monitored by the measurement points a and c of the infrared sensor unit 39c, and a temperature detection signal is detected (S4 '). The temperature detection signal is input to the correction circuit 100, and the internal addition circuit 104 adds the correction value stored in the memory 103 to the temperature detection signal, thereby correcting the temperature detection signal of the infrared sensor unit 39c. The detection value is output (S5 ′).

  Next, the temperature adjustment of the fixing roller 39a is performed as follows.

  Based on the corrected temperature detection value, the system controller 71 converts the fixing roller temperatures Ta and Tc [° C.] at the measurement points a and c (S6 ′). The fixing roller temperature Ta [° C.] at the measurement point a is compared with the fixing roller temperature T1 [° C.] at which the middle / high heater 208a is to be turned on (S7 ′).

  When the fixing roller temperature Ta [° C.] at the measurement point a is lower than T1, the middle / high heater 208a is turned on to heat the fixing roller 39a (S8 ').

  Here, when the fixing roller temperature Ta is higher than T1, the middle / high heater 208a is turned off (S9 ').

  Next, the fixing roller temperature Tc [° C.] at the measurement point c is compared with the fixing roller temperature T2 [° C.] at which the end high heater 208c is to be turned on (S10 ′).

  When the fixing roller temperature Tc [° C.] at the measurement point c is lower than T2, the end high heater 208c is turned on to heat the fixing roller 39a (S11 ').

  Here, when the fixing roller temperature Tc is higher than T2, the end high heater 208c is turned off (S12 ').

  If the above configuration is adopted, it is only necessary to use one temperature correction circuit as compared with the case where the infrared sensor unit is used for controlling the middle-high heater 208a and the end-high heater 208c, respectively. Therefore, it is possible to prevent image defects caused by erroneous detection due to dirt.

1 is a configuration diagram illustrating an example of an image forming apparatus. It is a figure for demonstrating the detail of an image formation part. 3 is a block diagram illustrating a temperature control system of a fixing unit. FIG. It is a block diagram which shows the temperature correction system of the non-contact temperature sensor unit with the structure of Embodiment 1 of this invention. It is a block diagram which shows the inside of the correction circuit in the temperature correction system of a non-contact temperature sensor unit. It is a flowchart which concerns on correction | amendment control of the non-contact temperature sensor unit in Embodiment 1 of this invention. It is sectional drawing of a non-contact temperature sensor unit. It is a block diagram which shows the temperature correction system of the non-contact temperature sensor unit with the structure of Embodiment 2 of this invention. It is a block diagram which shows the temperature correction system of the non-contact temperature sensor unit with the structure of Embodiment 3 of this invention. It is a graph which shows the light distribution characteristic of (a) middle-high heater and (b) edge part high heater in Embodiment 3 of this invention. It is a flowchart which concerns on correction | amendment control of the non-contact temperature sensor unit in Embodiment 3 of this invention.

Explanation of symbols

39a Fixing roller 39c Non-contact temperature sensor unit 39d Non-sheet passing portion contact thermistor 100 Correction circuit 208 Fixing heater 208a Middle high heater 208b End high heater

Claims (6)

  It has infrared temperature detection means as first temperature detection means that can detect at least two or more temperatures from one opening, and the vicinity detected by the infrared temperature detection means or at substantially the same temperature. A temperature detection device comprising second temperature detection means at a location estimated to be.   A heating source and a heated member heated by the heating source are provided, and the temperature of the heated member is controlled using the detected temperature of the second temperature detecting means and the infrared temperature detecting means according to claim 1. Characteristic temperature control means. A heating source, a heated member heated by the heating source, a pressure member disposed opposite to the heated member, and being nipped and conveyed between the heated member and the pressure member, In a fixing device for fixing an unfixed toner image of
Infrared temperature detecting means as first temperature detecting means capable of detecting the temperature of at least two locations of the heated member from one opening, and the vicinity of at least one location detected by the infrared temperature detecting means Or the value detected by the 2nd temperature detection means provided in the location presumed that it is substantially the same temperature, the infrared detection means as said 1st temperature detection means, and the value which the said 2nd temperature detection means detected And a temperature control means for controlling the temperature of the member to be heated.   At least one of the detection locations of the first temperature detection means is within the minimum size paper passing area in the heated member axial direction, and the detection location of the second temperature detection means is outside the maximum size paper passing area in the heated member axial direction. The fixing device according to claim 3, wherein:   The member to be heated is a rotating body, and one of the detection points of the first temperature detection unit and the detection point of the second temperature detection unit are on substantially the same circumference and the same height of the heating member. The fixing device according to claim 3.   The heating means includes a first heating means in which the heat generation amount near the center in the direction orthogonal to the recording material conveyance direction of the heating member is larger than the heat generation amount near the end, and a direction orthogonal to the recording material conveyance direction of the heating member. A second heating unit having a larger amount of heat generation near the end than a heat generation amount near the center, and at least one of the detection points of the first temperature detection unit is the first heating unit near the center of the heated member; It is a portion corresponding to a portion with a large amount of heat generation, and at least one of the detection portions of the first temperature detection means is a portion corresponding to a portion with a large amount of heat generation of the second heating means near the heated member end. The fixing device according to claim 3, wherein the detection portion of the second temperature detection means is outside the maximum size sheet passing area in the heated member axial direction.

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