JP2010026411A - Fixing device, image forming apparatus, control method for fixing device, and control program for fixing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of reducing erroneous detection of temperature. <P>SOLUTION: The fixing device includes: a temperature detection sensor that is arranged in non-contact with a heating roller that is a body to be measured, and detects temperature according to a quantity of infrared ray radiated from the body to be measured; a heating source that heats the body to be measured; a soil resistant member 609 that is constituted to be movable and covers a part of a light transmission part on which the infrared ray is made incident in the temperature detection sensor; and a detection part that detects the soil of the temperature detection sensor based on the received quantity of the infrared ray of the temperature detection sensor at a certain point of time and the received quantity of the infrared ray of the temperature detection sensor after moving the soil resistant member 609. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing device, an image forming apparatus, a fixing device control method, and a fixing device control program, and in particular, a fixing device that detects temperature with a temperature detection sensor, an image forming apparatus, a fixing device control method, and The present invention relates to a control program for a fixing device.

  In an electrophotographic image forming apparatus (MFP (Multi Function Peripheral), facsimile machine, copying machine, printer, multifunction machine, etc.), a fixing device that fixes toner on a sheet (recording medium) to the sheet with heat and pressure ( A fixing device) is provided.

  Generally, the fixing device includes a heating (fixing) roller (or a fixing belt) and a pressure roller. The toner is fixed to the paper by the pressure and heat between the rollers. The heating roller is formed of a cored bar and elastic rubber. As a result, a NIP (nip) is formed to ensure sufficient fixing performance.

  In a fixing device aiming at high durability, it is desirable to use a non-contact type temperature detecting element that can measure the temperature of the fixing belt or the fixing roller in a non-contact manner. This is to prevent damage to the fixing belt and the fixing roller due to wear at the contact portion. Under such a background, various non-contact temperature detection methods have been proposed and implemented. For example, there is a device that uses a thermopile that detects temperature according to the amount of infrared rays as a temperature detection element in the fixing device.

  The thermopile is a non-contact type temperature detecting element, and is configured by connecting a large number of thermocouples obtained by joining two kinds of metals or semiconductors in series.

  The thermopile transmits infrared rays radiated by heating the fixing belt and the fixing roller to an infrared transmission filter (infrared filter), and receives the transmitted infrared rays at a light receiving unit (thermocouple hot junction). The thermoelectromotive force generated between the thermocouple and the cold junction due to the Seebeck effect is measured. Based on the magnitude of the thermoelectromotive force, the surface temperature of the fixing belt and the fixing roller is calculated.

  Moreover, when a thermopile is used, temperature measurement is possible even when the measurement distance of the object to be measured is long. For this reason, it is possible to measure the temperature of the fixing belt and the fixing roller by installing a thermopile on the main body side, not in the fixing device. For this reason, even if it is necessary to replace the fixing device due to the life of the fixing device, it is not necessary to replace the thermopile, which is an expensive temperature detection element. This also has the effect of reducing user maintenance costs.

  Patent Document 1 below discloses a fixing device that prevents a decrease in sensor sensitivity by opening a diaphragm in accordance with dirt on an infrared absorbing film that is a light receiving unit of a non-contact temperature sensor.

Patent Document 2 below discloses a technique for correcting sensitivity variations among individual infrared sensors by providing an adjustable light shielding unit in the light guide unit of the infrared sensor and adjusting the amount of incident infrared rays.
JP 2006-98199 A JP 2002-156284 A

  In the non-contact type temperature sensor (thermopile), when the infrared filter becomes dirty, the amount of light incident on the infrared light receiving sensor (thermopile sensor) decreases. In this case, there is a problem that erroneous detection of temperature occurs.

  The present invention has been made to solve such problems, and provides a fixing device, an image forming apparatus, a fixing device control method, and a fixing device control program that can reduce erroneous detection of temperature. The purpose is to do.

  In order to achieve the above object, according to one aspect of the present invention, the fixing device is disposed in a non-contact manner with the measurement object, and a temperature detection member that detects the temperature according to the amount of infrared rays emitted from the measurement object; An antifouling member that covers a part of a translucent part that makes infrared rays enter in a heating source that heats the measurement object and a temperature detection member, and an antifouling member configured to be movable, and temperature detection at a certain point in time Detection means for detecting contamination of the temperature detection member based on the amount of infrared reception of the member and the amount of infrared reception of the temperature detection member after the antifouling member is moved.

  Preferably, the translucent part of the temperature detection member has a filter, and the antifouling member is a member that shields infrared rays, and the antifouling member is removed at a predetermined timing or at another place of the filter at a predetermined timing. The antifouling portion covered by the antifouling member is exposed by moving to.

  Preferably, the detection means has a table for determining the amount of dirt based on the difference in the amount of received infrared light before and after the exposure of the portion covered by the antifouling member.

  Preferably, the fixing device further includes a correction unit that corrects the temperature detected by the temperature detection member based on the amount of dirt detected by the detection unit.

  Preferably, when the difference between the amount of infrared light received by the temperature detection member at a certain point in time and the amount of infrared light received by the temperature detection member after moving the antifouling member exceeds a predetermined value, the detection means to decide.

  Preferably, the fixing device further includes an informing unit for informing when the detecting unit determines that there is dirt.

  Preferably, the fixing device further includes means for stopping the apparatus when the detection means determines that there is dirt.

  Preferably, the antifouling member is a fan-shaped member having a predetermined angle with respect to the center of the translucent part, and the fixing device is configured to prevent the antifouling with the center of the translucent part as an axis when detecting the dirt by the detecting means. The member is rotated by a predetermined angle or more.

  Preferably, the antifouling member moves in the dirt detection mode to expose the antifouling portion underneath and returns to the original position when the dirt detection mode is canceled.

  According to another aspect of the present invention, an image forming apparatus includes any of the fixing devices described above and an image forming unit that forms an image on a recording medium.

  According to still another aspect of the present invention, the temperature detection sensor that is arranged in a non-contact manner with the object to be measured and detects the temperature according to the amount of infrared rays emitted from the object to be measured includes An antifouling member that covers a part of the antifouling member is configured to be movable, and can measure both the amount of received infrared light at a certain point in time and the amount of received infrared light after the antifouling member is moved. Configured.

  According to still another aspect of the present invention, a temperature detection member that is disposed in a non-contact manner with the measured object and detects the temperature according to the amount of infrared rays emitted from the measured object, and a heating source that heats the measured object And a method for controlling a fixing device including a stain-proof member that covers a part of a light-transmitting portion that receives infrared rays and that is configured to be movable. A detection step of detecting contamination of the temperature detection member based on the amount of received light and the amount of infrared light received after the antifouling member is moved is provided.

  According to still another aspect of the present invention, a temperature detection member that is disposed in a non-contact manner with the measured object and detects the temperature according to the amount of infrared rays emitted from the measured object, and a heating source that heats the measured object And a temperature detection member, which is a stainproof member that covers a part of the translucent part that receives infrared rays and is configured to be movable, the control program of the fixing device includes a temperature at a certain point in time. Based on the amount of infrared light received by the detection member and the amount of infrared light received by the temperature detection member after the antifouling member is moved, the computer is caused to execute a detection step of detecting contamination of the temperature detection member.

  According to these inventions, it is possible to provide a fixing device, an image forming apparatus, a fixing device control method, and a fixing device control program that can reduce erroneous detection of temperature.

  Hereinafter, an electrophotographic image forming apparatus according to an embodiment of the present invention will be described.

  The image forming apparatus forms an image on a recording material by an electrophotographic method. The image forming apparatus includes a heat fixing device. The temperature of the fixing device is detected by two sensors, a non-contact type thermistor and a thermopile (non-contact type temperature detection element). The fixing device has a mode (detection state information acquisition mode) in which the dirt on the thermopile is detected while the heating roller is kept at a constant temperature (temperature control state). Based on the detection state information acquired in this mode, the degree of contamination of the thermopile is detected in advance, and erroneous temperature detection is prevented. A part of the thermopile lens or the infrared filter is covered with an antifouling member. In the dirt detection mode, the dirt on the thermopile lens (infrared filter) is detected by moving the antifouling member.

  [First Embodiment]

  FIG. 1 is a diagram showing a configuration of an image forming apparatus according to the first embodiment of the present invention.

  First, a schematic configuration of the image forming apparatus 1501 will be described. The image forming apparatus 1501 includes an intermediate transfer belt 1502 as a belt member at a substantially central portion inside the image forming apparatus 1501. The intermediate transfer belt 1502 is supported on the outer periphery of the rollers 1504 and 1505 and is driven to rotate in the direction of arrow A. The intermediate transfer belt drive roller 1505 is connected to a drive motor (not shown), and the roller 1504 is driven to rotate as the intermediate transfer belt drive roller 1505 rotates.

  Below the lower horizontal portion of the intermediate transfer belt 1502, four image forming units 1506Y, 1506M, 1506C, respectively corresponding to the respective colors of yellow (Y), magenta (M), cyan (C), and black (K), 1506K are arranged side by side along the intermediate transfer belt 1502.

  Each of the image forming units 1506Y, 1506M, 1506C, and 1506K has a photosensitive drum 1507Y, 1507M, 1507C, and 1507K, respectively. Around each of the photosensitive drums 1507Y, 1507M, 1507C, and 1507K, the photosensitive members 1508, the print head unit 1509, the developing device 1510, and the intermediate transfer belt 1502 are sandwiched in order along the rotation direction. Primary transfer rollers 1511Y, 1511M, 1511C, and 1511K facing the drums 1507Y, 1507M, 1507C, and 1507K, and a cleaner 1512 are arranged, respectively.

  A secondary transfer roller 1503 is pressed against a portion of the intermediate transfer belt 1502 supported by the intermediate transfer belt driving roller 1505, and a nip (NIP) portion between the secondary transfer roller 1503 and the intermediate transfer belt 1502 is 2 A next transfer area 1530 is formed.

  A fixing device 1520 including a heating roller 1521, a pressure roller 1522, and a magnetic flux generator 1523 is disposed at a downstream position of the conveyance path 1541 behind the secondary transfer region 1530. A pressure contact portion between the heating roller 1521 and the pressure roller 1522 is a fixing NIP region 1531.

  A paper feed cassette 1517 is detachably disposed below the image forming apparatus 1501. The sheets P stacked and accommodated in the sheet feeding cassette 1517 are sent out one by one from the uppermost one to the conveyance path 1540 by the rotation of the sheet feeding roller 1518.

  An AIDC (image density) sensor 1519 also serving as a registration sensor is installed between the image forming unit 1506K on the most downstream side of the intermediate transfer belt 1502 and the secondary transfer region 1530. This registration sensor 1519 measures the interval between the patterns of the respective colors formed on the intermediate transfer belt 1502 and compares the interval with a predetermined reference value to adjust the start timing of writing the image of each color. belongs to.

  Next, a schematic operation of the image forming apparatus 1501 having the above configuration will be described.

  When an image signal is input from an external device (for example, a personal computer) to an image signal processing unit (not shown) of the image forming apparatus 1501, the image signal processing unit performs color conversion of the image signal into yellow, cyan, magenta, and black. The digital image signal is generated, and the print head unit 1509 of each of the image forming units 1506Y, 1506M, 1506C, and 1506K is caused to emit light based on the input digital signal. Thereby, electrostatic latent images for the respective colors are formed on the surfaces of the photosensitive drums 1507Y, 1507M, 1507C, and 1507K, respectively.

  The electrostatic latent images formed on the photosensitive drums 1507Y, 1507M, 1507C, and 1507K are respectively developed by the developing units 1510 to become toner images of the respective colors. Then, the toner images of the respective colors are primary-transferred by being sequentially superimposed on the intermediate transfer belt 1502 moving in the arrow A direction by the action of the primary transfer rollers 1511Y, 1511M, 1511C, and 1511K.

  The superimposed toner image formed on the intermediate transfer belt 1502 in this way reaches the secondary transfer region 1530 as the intermediate transfer belt 1502 moves. In the secondary transfer region 1530, the superimposed toner images are secondarily transferred to the sheet P conveyed by the timing roller 1570 by the action of the secondary transfer roller 1503.

  Next, the toner image secondarily transferred to the paper P reaches the fixing NIP area 1531. In the fixing NIP region 1531, the toner image is fixed on the paper P by the action of the heating roller 1521 and the pressure roller 1522 that generate induction heat by the magnetic flux generation unit 1523.

  The paper P on which the toner image is fixed is discharged to a paper discharge tray 1513 via a paper discharge roller 1514.

  In addition, the reference position of the paper P is determined by the timing roller 1570.

  The arrangement and method of each element in FIG. 1 may be changed as appropriate according to the apparatus.

  The image forming apparatus may be a monochrome / color copying machine, a printer, a FAX, or a complex machine of these.

  FIG. 2 is a diagram showing a cross-sectional configuration of the fixing device 1520 of FIG.

  Here, a fixing device for a color laser printer is illustrated.

  Referring to the figure, the fixing device includes a heating roller 1521, a pressure roller 1522, a magnetic flux generator 1523, and a separation claw 8. The magnetic flux generator 1523 includes an exciting coil 31, a magnetic core 32, and a coil bobbin 33. In the drawing, the toner is attached to the upper surface of the paper P, and the paper P is conveyed from the left to the right in the drawing by the roller 70.

  The heating roller 1521 and the pressure roller 1522 are arranged in parallel in the vertical direction, and both ends are rotatably supported by bearing members (not shown). The pressure roller 1522 is urged in the direction of the rotation axis of the heating roller 1521 by a pressure mechanism (not shown) using a spring or the like. A pressure nip (fixing nip) is formed by bringing the pressure roller 1522 into pressure contact with the lower surface of the heating roller 1521 with a predetermined pressure.

  The pressure roller 1522 is rotationally driven in a clockwise direction indicated by an arrow at a predetermined peripheral speed by a drive mechanism (not shown). The heating roller 1521 is rotated by the rotation of the pressure roller 1522 by the pressure frictional force with the pressure roller 1522 at the pressure nip portion. Note that the heating roller 1521 may be driven to rotate, and the pressure roller 1522 may be driven to rotate. That is, the relationship between driving and driven may be reversed.

  FIG. 3 is a diagram showing a schematic concept of the heating roller 1521.

  The heating roller 1521 has a layer configuration, and in order from the inside to the outside, the core metal 11 as a support layer, the heat insulating layer (Si sponge layer) 12, the electromagnetic induction heating layer 13, the elastic layer (Si rubber layer) 14, and It has a five-layer structure of a release layer (fluororesin layer) 15. The roller hardness is, for example, an ASKER-C hardness of 30 to 90 degrees.

  The metal core 11 as the support layer is made of aluminum having a thickness of 4 mm. The material only needs to be strong, and for example, iron or a heat-resistant molded pipe such as PPS (polyphenylene sulfide) can be used. However, in order to prevent the cored bar from generating heat, it is desirable to use a nonmagnetic material that is less affected by electromagnetic induction heating.

  The heat insulation layer 12 is for heat insulation holding of the electromagnetic induction heat generating layer 13, and a heat-resistant and elastic rubber material or a sponge material (heat insulation structure) of resin material is used. By using a heat-resistant and elastic rubber or resin sponge (heat insulation structure) for the heat insulating layer 12, the electromagnetic induction heat generating layer 13 is insulated and held. Further, it plays the role of allowing the deflection of the electromagnetic induction heat generating layer 13 to increase the pressure nip width and reducing the roller hardness to improve the paper discharge performance and the recording material separation performance.

  The heat insulating layer 12 may have a two-layer structure of a rubber material and a sponge body.

  For example, when a silicon sponge material is used for the heat insulating layer 12, the thickness is 2 to 12 mm (preferably 3 to 10 mm), and the hardness is 20 to 60 degrees (preferably 30 to 50 degrees) with an Asker rubber hardness meter. Is set.

  The electromagnetic induction heat generating layer 13 in the present embodiment is an endless nickel electroformed belt layer having a thickness of 10 to 100 μm (preferably 20 to 50 μm). As another material of the electromagnetic induction heat generating layer 13, a material having a relatively high magnetic permeability μ and an appropriate resistivity ρ such as a magnetic material (magnetic metal) such as magnetic stainless steel may be used. Furthermore, even a nonmagnetic material can be used by making the material a thin film as long as it is a conductive material such as metal.

  The electromagnetic induction exothermic layer 13 may be a resin in which exothermic particles are dispersed. Separation can be improved by using a resin-based material for the electromagnetic induction heat generating layer 13.

  Next, the elastic layer 14 will be described. The elastic layer 14 serves to increase the adhesion between the recording material and the surface of the heating roller. The elastic layer 14 is a layer of heat-resistant and elastic rubber material or resin material, and heat-resistant elastomers such as silicon rubber and fluororubber that can withstand use at a fixing temperature can be used.

  Various fillers may be mixed into the elastic layer 14 for the purpose of improving thermal conductivity, reinforcing, or the like. Examples of the thermally conductive particles include diamond, silver, copper, aluminum, marble, and glass. Practically, silica, alumina, magnesium oxide, boron nitride, beryllium oxide, and the like are used.

  For example, the thickness of the elastic layer 14 is preferably 10 to 800 μm, and more preferably 100 to 300 μm. When the thickness of the elastic layer is less than 10 μm, it is difficult to obtain the desired elasticity in the thickness direction. On the other hand, when the thickness exceeds 800 μm, the heat generated in the heat generating layer hardly reaches the outer peripheral surface of the fixing film, and the thermal efficiency tends to deteriorate.

  The elastic layer 14 is preferably made of silicon rubber having a JIS hardness of 1 to 80 degrees (desirably 5 to 30 degrees). Within this JIS hardness range, it is possible to prevent poor toner fixability while preventing a decrease in strength of the elastic layer and poor adhesion.

  Specifically, one-component, two-component or three-component or more silicone rubber, LTV type, RTV type or HTV type silicon rubber, condensation type or addition type silicon rubber can be used as this silicon rubber. . In the present embodiment, the elastic layer 14 is a silicon rubber layer having a JIS hardness of 10 degrees and a thickness of 200 μm.

  The outermost release layer 15 is for enhancing the release property on the surface of the heating roller. The release layer 15 can withstand use at the fixing temperature and has toner release properties. As the release layer 15, for example, silicon rubber, fluororubber, or fluororesin such as PFA, PTFE, FEP, and PFEP is preferably used. 5-100 micrometers is preferable and, as for the thickness of a mold release layer, 10-50 micrometers is more preferable. Further, in order to improve the interlayer adhesion, an adhesion treatment with a primer or the like may be performed. In addition, a conductive material, an abrasion resistant material, and a good heat conductive material can be added to the release layer 15 as necessary.

  The magnetic flux generator 1523 is disposed outside the heating roller 1521 and causes the generated magnetic flux to act on the electromagnetic induction heat generating layer 13 from the outer surface side of the heating roller 1521.

  Since the heat capacity of the electromagnetic induction heat generating layer 13 that contributes to heat generation and generates eddy current is small, and the electromagnetic induction heat generating layer 13 is insulated and held by the sponge layer 12, the elastic layer 14 on the heating roller surface layer side or the separation layer is separated. The mold layer 15 is rapidly heated. The surface of the heating roller can quickly reach the temperature required for fixing, and can catch up with the supply of heat even if the paper P such as paper or an OHP sheet is deprived of heat.

  FIG. 4 is a diagram showing a schematic configuration of the pressure roller 1522.

  The pressure roller 1522 has an elastic layer 22 made of silicon sponge rubber having a thickness of 3 to 10 mm on the outer periphery of an aluminum core bar 21 having a thickness of 3 mm, and further improves the surface releasability like the heating roller 1521. The mold release layer 25 is provided.

  As the release layer 25, for example, a fluororesin release layer having a thickness of 10 to 50 μm such as PTFE or PFA is provided to form a roller.

  As long as the material of the core metal 21 can secure the strength, for example, a pipe of a heat resistant mold such as iron or PPS (polyphenylene sulfide) can be used. It is desirable to use a nonmagnetic material that is less affected by induction heating.

  The pressure roller 1522 is pressed against the heating roller 1521 with a load of 300 to 500N. In this case, the nip width is about 5 to 15 mm. Depending on circumstances, the nip width may be changed by changing the load.

  The thickness of the heat insulating layer 22 can be appropriately changed in accordance with the use conditions in the range of 3 to 10 mm. The heat insulating layer 22 may have a two-layer structure of silicon rubber and silicon sponge.

  The material and configuration of the roller and the like are not limited to the present embodiment. The time may be changed according to the device.

  In FIG. 2, the magnetic flux generator 1523 includes an exciting coil 31, a magnetic core 32, and a coil bobbin 33. The magnetic flux generator 1523 is disposed outside the heating roller 1521 so as to face the heating roller 1521 and along the longitudinal direction of the heating roller.

  The magnetic core 32 is a long member having a trapezoidal cross section and a length dimension substantially corresponding to the longitudinal dimension of the heating roller 1521. Furthermore, the heat generation efficiency can be increased by providing an E-shaped cross section and a core projecting toward the heating roller at the center. As the magnetic core 32, one having high magnetic permeability and low loss is used. In the case of an alloy such as permalloy, an eddy current loss in the core increases at a high frequency, so a laminated structure may be used.

  The core 32 is used for increasing the efficiency of the magnetic circuit and for magnetic shielding. The magnetic circuit portions of the exciting coil 31 and the core 32 may be air cores (no core) if there is a mechanism that can sufficiently shield the magnetic field. When a resin material in which magnetic powder is dispersed is used, the magnetic permeability is relatively low, but the shape can be freely set.

  The exciting coil 31 has a trapezoidal cross section and has a structure in which a conducting wire is wound along the longitudinal direction of the fixing roller 1521, and a magnetic core 32 is provided so as to cover the outer surface of the exciting coil 31.

  The exciting coil 31 is connected to a high-frequency inverter (not shown) and is supplied with high-frequency power of 10 to 100 [kHz] and 100 to 2000 [W]. The exciting coil 31 is a litz wire made by bundling several tens to several hundreds of thin wires. In consideration of the case where heat is transferred to the winding, a material coated with a heat resistant resin is used. The

  The magnetic flux induced by the alternating current passes through the inside of the magnetic core 32 without leaking to the outside, and leaks to the outside of the magnetic core for the first time between the protrusions of the core, and the electromagnetic induction heating layer 13 of the heating roller 1521 (FIG. 3). Pierce. Thereby, an eddy current flows through the electromagnetic induction heat generating layer 13 and the conductive layer itself generates Joule heat. The heating roller 1521 is heated by the heat generated by the electromagnetic induction heat generating layer 13.

  In the fixing operation, the pressure roller 1522 is rotationally driven, and accordingly, the heating roller 1521 is also driven to rotate. The conductive layer 13 as the electromagnetic induction heat generating layer of the heating roller 1521 generates electromagnetic induction heat by the action of the magnetic flux generated by the magnetic flux generation unit 1523, and is automatically controlled so that the surface temperature of the heating roller 1521 becomes a predetermined constant temperature. . In this state, a sheet on which an unfixed toner image is formed and carried, which is conveyed from the timing roller 1570 to the pressure nip portion between the heating roller 1521 and the pressure roller 1522 and secondarily transferred in the secondary transfer region. P is introduced. In this case, the surface on which the unfixed toner image is formed on the paper P faces the heating roller 1521.

  The recording material P introduced into the pressure nip portion between the heating roller 1521 and the pressure roller 1522 is nipped and conveyed by the pressure nip portion, heated by the heating roller 1521, and the unfixed toner image is melted and fixed on the paper P. .

  The paper P that has passed through the pressure nip is separated from the heating roller 1521 and discharged and conveyed. The separation claw 8 is disposed in contact with the surface of the heating roller 1521. When the paper P sticks to the surface of the heating roller 1521 after passing through the pressure nip portion, the separation claw 8 is for forcibly separating it from the surface of the heating roller 1521 to prevent jamming.

  The arrangement of the separation claws 8 is not limited to contact with the heating roller 1521 but may be non-contact.

  The heating roller 1521 can be composed of at least four layers of a support layer (core metal) 11, a heat insulating layer 12, an electromagnetic induction heat generating layer 13, and a release layer 15 in order from the inside to the outside. Furthermore, in this embodiment, as shown in FIG. 3, an elastic layer 14 is provided for accommodating color images.

  FIG. 5 is a diagram showing a detailed configuration of the central section of the fixing device 1520.

  As described above, the fixing device 1520 includes the heating roller 1521, the pressure roller 1522, and the magnetic flux generator 1523.

  In the present embodiment, the soaking roller 9 is pressed against the pressure roller 1522 in order to reduce the temperature unevenness in the longitudinal direction of the fixing nip portion formed by pressing the heating roller 1521 and the pressure roller 1522. ing.

  In order to measure the surface temperature of the heating roller 1521 and perform temperature control, the non-contact temperature sensor unit 40 is disposed at a position where the heating roller 1521 can be seen. The non-contact type temperature sensor unit 40 is attached to a temperature sensor unit drive board 41. Three non-contact temperature sensor units 40 are provided. The arrangement will be described with reference to FIG.

  The temperature sensor unit drive board 41 is connected to a mechanical control (mechanical controller) board (control board) (not shown), and the magnetic flux generation unit 1523 is controlled via the CPU of the mechanical control board. The temperature sensor unit drive board 41 is fixed to the main body frame by a temperature sensor unit mounting plate 42.

  As the non-contact type temperature sensor unit 40, what is called a thermopile is preferably used. According to the present embodiment, control is performed to solve problems caused by contamination of the non-contact type temperature sensor unit 40.

  The fixing device is configured to be separated at an alternate long and short dash line in the drawing. The right side is a unit portion of the fixing device, and the left side is a main body side of the image forming apparatus. The magnetic flux generator 1523 and the non-contact temperature sensor unit 40 are attached to the main body side of the image forming apparatus. Thereby, even when the unit portion of the fixing device is replaced, the magnetic flux generation unit 1523 and the non-contact temperature sensor unit 40 can be reused as they are.

  FIG. 6 is a plan view of the arrangement of the rollers in FIG.

  Non-contact temperature sensor units (thermopiles) 401 to 403 are arranged in the longitudinal direction of the heating roller 1521 and are arranged not on the fixing device but on the main body side of the image forming apparatus. These three non-contact type temperature sensor units (thermopiles) have different functions.

  In the present embodiment, temperature adjustment (temperature adjustment of the heating roller) is performed based on the output of the non-contact type temperature sensor unit 401 disposed almost at the center.

  The non-contact temperature sensor unit 402 measures the temperature at a position closer to the left than the center portion of the heating roller 1521 in the drawing. The measured temperature at that position is used to limit the number of sheets passed. That is, the non-contact type temperature sensor unit 402 performs so-called CPM control, which is control for stopping paper feeding (or opening a paper feeding interval (paper gap)) when the temperature rises above a predetermined reference. Used for that.

  The non-contact temperature sensor unit 403 measures the temperature at a position (near the end of the heating roller 1521) that is closer to the right than the center of the heating roller 1521 in the drawing. The measured temperature at that position is used to switch the heating state of the heating roller 1521. That is, the non-contact type temperature sensor unit 403 is used for control to reduce the heat generation amount at both ends of the roller when the temperature rises to a predetermined reference or more. As a method for reducing the amount of heat generation, it is conceivable to stop energization to both ends of the divided coil, operate a cancel coil arranged at both ends, and control the magnetic flux at both ends.

  A non-contact thermistor 6 is disposed in the vicinity of the non-contact temperature sensor unit 401. The non-contact type temperature sensor units 401 to 403 measure the temperature by detecting the amount of infrared rays, while the thermistor 6 measures the temperature by directly detecting heat due to convection, heat conduction, and radiation. For this reason, there is a feature that the measurement error increases as the distance from the heating roller 1521 as the measurement object is increased.

  The non-contact type thermistor 6 and the non-contact type temperature sensor units 401 to 403 are disposed on substantially the same line. By arranging them on the same line, the temperature difference in the circumferential direction of the roller can be ignored.

  In the present embodiment, the non-contact thermistor 6 is not in contact with the heating roller 1521. The non-contact type thermistor 6 is disposed on the fixing device unit side. The non-contact type thermistor 6 is arranged for protection when the non-contact type temperature sensor unit 401 fails. When the detected temperature of the non-contact thermistor 6 exceeds a predetermined value, measures such as stopping the power supply or issuing a warning are taken as an abnormally high temperature.

  Further, a non-contact thermostat 451 is provided between the non-contact type temperature sensor unit 401 and the non-contact type temperature sensor unit 403. The soaking roller 9 is provided with non-contact thermistors 452 and 453 that measure the temperature and a non-contact thermostat 454.

  A contact type thermistor 7 is disposed in the non-sheet passing region of the heating roller 1521. This is used to control the temperature of the heating roller 1521 to a constant temperature when detecting dirt.

  FIG. 7 is a perspective view in which a part of the non-contact type temperature sensor unit 40 is broken.

  The non-contact type temperature sensor unit 40 houses a thermopile chip 51 as a non-contact type temperature sensor that receives infrared rays emitted from the heating roller 1521, a thermistor 52 as a correction sensor that compensates the temperature of the thermopile chip 51, and these. A unit case 53 is included.

  The unit case 53 includes a substantially cylindrical base 54 having a flange portion around it, and a cylindrical housing 55 that is integrated with the flange so as to be fitted. The cylindrical casing 55 has a hole 56 at the top, and receives infrared rays from the hole 56. The hole 56 is sealed with an infrared transmission filter (translucent portion) 57. An inert gas (such as nitrogen gas or argon gas) is preferably sealed in the unit.

  The thermopile chip 51 is obtained by arranging a hot junction of a thermopile 51a, which is a temperature measuring element, on an insulating film having a small heat capacity (not shown) and a cold junction on a silicon heat sink 51b. There are three contacts from the base 54. These contacts are a thermopile output terminal 58a, a temperature compensation thermistor output terminal 58b, and a GND 58c, respectively. These terminals are connected to the temperature sensor unit substrate 41 (FIG. 5). The temperature is corrected and output as an actual temperature with a small error.

  FIG. 8 is a block diagram illustrating a temperature control device provided in the image forming apparatus 1501.

  Referring to the figure, the temperature control device displays the above-mentioned non-contact, contact thermistors 6 and 7, non-contact type temperature sensor units 401 to 403, a control board 601 including a CPU, and a warning to the user. A display input unit 603 that accepts the input of, and a communication unit 605 that communicates with the service center. The magnetic flux generator 1523 is controlled based on the temperature detection result.

  The control board 601 is connected to a motor and gear 607 for rotating the thermopile antifouling member.

  FIG. 9 is a diagram showing a configuration of the antifouling member provided in the non-contact type temperature sensor unit 40.

  FIG. 9A is a view of the non-contact type temperature sensor unit 40 as seen from above, and FIG. 9B is a view as seen from the side.

  The infrared transmission filter 57 (translucent portion) provided on the top of the non-contact temperature sensor unit 40 is provided with an antifouling member (antifouling plate) 609 that hides the range of the angle θ from the center. The antifouling member 609 may be made of any material as long as it is a member that does not transmit infrared rays. The antifouling member 609 is attached to the inner periphery of the ring member that surrounds the outer periphery of the infrared transmission filter 57. A gear 607a is formed on the outer periphery of the ring member. The gear 607a is rotationally driven by the motor and the gear 607. By the rotational drive of the gear 607a, the antifouling member 609 rotates about the center of the infrared transmission filter 57 as a rotation axis.

  FIG. 10 is a top view of the non-contact temperature sensor unit 40 in a state where the antifouling member 609 is rotated by a predetermined angle from the state of FIG.

  When the dirt of the infrared transmission filter 57 is detected, the antifouling member 609 is rotated by a motor and a gear as shown in FIG. By using a stepping motor as the motor and managing the amount of rotation, it becomes easy to return the antifouling member to the initial position.

  The place where the antifouling member 609 is located on the infrared transmission filter 57 in the state of FIG. 9 is a clean surface that does not get dirty. When the dirt is detected, temperature measurement is performed using a clean surface 611 of the infrared transmission filter 57 as shown in FIG. The degree of contamination can be detected by observing the difference between the measured temperature in the state of FIG. 9 and the measured temperature in the state of FIG.

  When it is determined that there is no dirt in the detection result, the sensor is used with the antifouling member 609 returned to the original position in FIG. Also, if the detection result is determined to be “contaminated” and the amount of contamination exceeds a predetermined amount, a warning is issued and processing for prompting the operator to perform cleaning is performed.

  11 to 13 are diagrams for illustrating effects in the present embodiment.

  FIG. 11 is a graph showing the detection temperature of the thermopile when the thermopile is dirty, FIG. 12 is a graph showing the temperature of the heating roller when the temperature is adjusted with the dirty thermopile, and FIG. It is a graph which compares the output of the thermopile before and behind member rotation.

  As shown in FIG. 11, when measuring an object to be measured (heating roller or the like) having an actual temperature of 180 ° C., there is a problem that the detected temperature is lowered as indicated by an arrow if the infrared filter is dirty. The greater the amount of dirt, the greater the degree of decrease in detection temperature. If the temperature is adjusted using a dirty sensor, the temperature is controlled to be high as shown by the arrow in FIG. For example, if the sensor becomes dirty even though it is desired to set the object to be measured to 180 ° C., the object to be measured becomes a temperature higher than that. This causes a problem of image deterioration such as high temperature offset and deterioration of durability of the heating roller rubber.

  In order to prevent such a problem, the image forming apparatus according to the present embodiment has a mode (“detection state information acquisition mode”) for detecting filter contamination. In this mode, the temperature of the heating roller 1521 is adjusted to a constant temperature by a sensor (contact type thermistor 7 in FIG. 6) arranged in contact with the non-image area of the heating roller 1521. In this state, by looking at the output difference between the detected temperature of the non-contact type temperature sensor unit 40 in the state before rotating the antifouling member 609 and the detected temperature of the non-contact type temperature sensor unit 40 after rotating, The contamination of the infrared filter is detected (FIG. 13). For example, if this difference is 3 ° C. or more, it can be determined that the filter is dirty.

  When the temperature difference is found to be greater than or equal to the predetermined amount in this way, a warning is given to indicate an abnormality, and the operator is urged to clean the non-contact temperature sensor unit 40. Alternatively, measures such as prompting replacement or stopping power supply may be performed.

  FIG. 14 is a flowchart showing a self-check operation of the non-contact type temperature sensor unit 40 executed by the image forming apparatus 1501.

  This self-check is executed in the “detection state information acquisition mode”. In the “detection state information acquisition mode”, a self-check is executed when an image is not formed (when printing is not performed).

  The detection state information acquisition mode is executed every time a predetermined period elapses when the power is turned on or by a command input from the user. That is, the detection state information acquisition mode can be controlled so as to be entered when an instruction to detect contamination of the non-contact type temperature sensor unit is issued. Further, the printing may be made periodically every fixed number of prints, or may be made every fixed operation time.

  In step S101, the heating roller 1521 is set to a predetermined temperature (for example, 180 ° C. which is a fixing temperature) using the measurement result of the contact type thermistor 7. The temperature of the heating roller 1521 is measured using the non-contact temperature sensor unit 40 in step S103 with the heating roller 1521 kept at the set temperature for image formation. The measurement temperature at this time is defined as temperature A.

  In step S105, the antifouling member 609 is rotated by a predetermined angle. In order to completely expose the surface of the filter (lens) covered with the antifouling member 609, it is desirable that the rotation angle be equal to or greater than the central angle θ of the antifouling member 609. In step S <b> 107, the temperature of the heating roller 1521 is measured using the non-contact type temperature sensor unit 40. The measurement temperature at this time is defined as temperature B.

  In step S109, the difference between temperature A and temperature B is obtained. In step S111, it is determined whether the difference exceeds a predetermined value (eg, 3 ° C.).

  If YES in step S111, it is determined that a measurement error of the non-contact temperature sensor unit 40 has occurred due to contamination of the non-contact temperature sensor unit 40, etc., and an error is displayed on the display unit 603 in step S113. At 605, a call is sent to the service center. Further, the heating of the heating source of the heating roller is stopped (the apparatus is stopped).

  On the other hand, if NO in step S111, it is determined that the result is good in step S115, and the self-check is terminated.

  In this manner, in the present embodiment, a part of the infrared incident surface of the non-contact temperature sensor unit 40 is covered with the antifouling member. The amount of infrared light received by the non-contact type temperature sensor unit 40 at a certain time and the amount of infrared light received by the non-contact type temperature sensor unit 40 after the antifouling member is moved are measured. Even when the part of the filter not covered with the antifouling member is dirty, the part of the filter covered with the antifouling member does not get dirty. For this reason, the amount of infrared rays received by the non-contact temperature sensor unit 40 after the antifouling member is moved is greater than before the movement. Based on this characteristic, the contamination of the filter of the non-contact temperature sensor unit 40 can be detected.

  [Second Embodiment]

  Hereinafter, the difference between the image forming apparatus according to the second embodiment of the present invention and that according to the first embodiment will be described.

  The image forming apparatus according to the second embodiment has a table for determining the amount of contamination of the non-contact temperature sensor unit 40 based on the difference in the amount of received infrared light before and after the exposure of the portion covered by the antifouling member. In the memory in the control board 601. Using this table, it is determined whether or not the non-contact temperature sensor unit 40 is contaminated. If there is dirt, different processing is performed depending on the degree.

  FIG. 15 is a diagram illustrating a table for determining the degree of contamination of the non-contact type temperature sensor unit 40 held by the image forming apparatus according to the second embodiment.

  For each difference in the amount of received infrared light before and after exposure of the portion covered by the antifouling member, the result of the dirt determination and the display content of the check result in the display / input unit 603 are recorded.

  When the difference in the amount of received light is 1 to 2 ° C., it is determined that the non-contact temperature sensor unit 40 is not soiled. The display / input unit 603 displays that the check result is OK.

  When the difference in the amount of received light is 3 to 5 ° C., it is determined that the non-contact temperature sensor unit 40 is slightly contaminated. The display / input unit 603 displays a message prompting early cleaning of the sensor as a check result.

  When the difference in the amount of received light is 6 to 9 ° C., it is determined that the non-contact temperature sensor unit 40 is dirty. The display / input unit 603 displays a message prompting cleaning of the sensor as a check result.

  When the difference in the amount of received light is 10 ° C. or more, it is determined that the non-contact type temperature sensor unit 40 is dirty. The display / input unit 603 displays a message prompting cleaning of the sensor as a check result. Also, the device is stopped.

  FIG. 16 is a flowchart showing a self-check operation of the non-contact temperature sensor unit 40 executed by the image forming apparatus according to the second embodiment.

  First, after the processing up to step S107 in the flowchart of FIG. 14 is executed, the processing of FIG. 16 is executed.

  In step S109, the difference between the temperature A and the temperature B is obtained. In step S121, it is determined whether the difference is less than 3 ° C. If YES, it is determined in step S129 that there is no dirt, and OK is displayed.

  If “NO” in the step S121, it is determined whether or not the difference is 3 ° C. or more and less than 6 ° C. in a step S123. If YES, it is determined in step S131 that there is a little dirt, and the message “Please clean as soon as possible” is displayed.

  If “NO” in the step S123, it is determined whether or not the difference is 6 ° C. or more and less than 10 ° C. in a step S125. If YES, it is determined in step S133 that there is dirt, and a message “please clean” is displayed.

  If “NO” in the step S125, it indicates that the difference is 10 ° C. or more (S127), so that it is determined that there is dirt in a step S135, and “clean it” is displayed. Also, the device is stopped.

  As described above, the image forming apparatus according to the present embodiment has a table for determining the degree of contamination according to the amount of received light. The degree of contamination is determined from the difference in detected temperature before and after the movement of the antifouling member, and displayed on the operation panel or the like. If there is a difference between 3 ° C and 6 ° C, it is dirty and prompts early cleaning. If it exceeds 6-9 ° C, cleaning is strongly encouraged, and if it exceeds 10 ° C, the device is stopped to prompt cleaning. The table can be stored in the CPU of the apparatus, and the apparatus is controlled by comparing the contamination detection result with the table.

  [Optimal size of antifouling material]

  Next, a preferable size (size) of the antifouling member 609 will be described.

  If the antifouling member is made too large, the sensor output decreases (including when the filter is not dirty), and there is a problem that the sensitivity of the sensor deteriorates. Experiments have shown that the sensor can be used well if the sensor output is reduced by about 30% from the output of the thermopile that is normally used (the output is reduced so that the maximum output of the sensor is 70%).

  Further, it has been experimentally known that the difference in sensor output before and after the movement of the antifouling member 609 cannot be detected as a difference including various variations unless it is 3% or more.

  Based on these two constraints, the size of the antifouling member is preferably such that it hides the infrared filter by 10 to 30% for the following reasons.

  FIG. 17 is a diagram showing the relationship between the area of the antifouling member and the output of the non-contact type temperature sensor unit 40.

  The horizontal axis of the graph indicates the area of the antifouling member 609 relative to the area of the light transmitting part of the infrared transmission filter 57. The left vertical axis indicates the output of the non-contact temperature sensor unit 40 when the infrared transmission filter 57 is not dirty. This shows the output when the output without the antifouling member 609 is 100%. As indicated by black circles and dotted lines in the graph, the sensor output decreases as the area of the antifouling member 609 increases.

  Further, the sensor output ratio before and after the movement of the antifouling member 609 when the infrared transmission filter 57 becomes dirty and the light transmittance becomes 80% is indicated by the solid line and the right vertical axis.

  As described above, the sensor output difference before and after the movement of the antifouling member 609 cannot be detected as a difference including various variations unless it is 3% or more. Therefore, the area of the antifouling member 609 is the area of the infrared transmission filter 57. It is necessary to be 10% or more.

  Further, since the decrease in the sensor output value due to the antifouling member 609 needs to be limited to about 30% (about the sensor output becomes 70%), the area of the antifouling member 609 is 30 times the area of the infrared transmission filter 57. % Or less. Accordingly, the size of the antifouling member 609 is preferably such a size that the infrared filter is hidden by 10 to 30%.

  [Third Embodiment]

  The difference between the image forming apparatus in the third embodiment of the present invention and that in the first embodiment will be described below.

  In the image forming apparatus according to the third embodiment, it is assumed that the service person cleans the infrared filter, for example, at the time of periodic inspection by the service person.

  FIG. 18 is a view of the non-contact type temperature sensor unit 40 included in the image forming apparatus according to the third embodiment as viewed from the infrared transmission filter 57 side.

  The antifouling member 609 is fixed to a ring surrounding the infrared transmission filter 57. By rotating the ring with a finger, the antifouling member 609 can be rotated about the center of the infrared transmission filter 57 as a rotation axis.

  FIG. 18A shows the position of the antifouling member 609 during normal use. In this state, the protrusion 653 provided on the ring and the lock mechanism 651 are engaged. Thereby, the antifouling member 609 can always be in a fixed position during normal use.

  FIG. 18B is a diagram showing the position of the antifouling member 609 in the dirt confirmation mode. When the serviceman rotates the ring with his / her finger, the engagement state between the protrusion 653 and the lock mechanism 651 is released.

  In the state shown in FIG. 18A, the serviceman cleans the infrared filter 57, sets the apparatus to the dirt check mode, and measures the dirt on the infrared transmission filter 57. In this mode, the temperature of the heating roller 1521 is adjusted by the contact thermistor 7 set outside the image area. First, the measurement temperature before rotation of the antifouling member is acquired. The service person manually rotates the antifouling member in order to confirm how the filter is cleaned by cleaning. This shifts to the state of FIG. In this state, the clean surface 611 that was hidden during normal use is exposed. When the measured temperature difference of the non-contact type temperature sensor unit 40 before and after the rotation is less than 3 ° C., the serviceman returns the antifouling member to the original position (FIG. 18A) and cancels the dirt check mode.

  If the temperature difference between before and after the rotation is 3 ° C. or more, the service person cleans the filter again and checks in the dirt check mode. Thereby, in this Embodiment, since the stain | pollution | contamination of an infrared filter can be cleaned reliably, problems, such as high fluctuation of the temperature control temperature resulting from a stain | pollution | contamination, can be prevented beforehand.

  In order to facilitate the movement of the antifouling member, an operation member such as a lever may be provided on the ring, or a mechanism for rotating the antifouling member with a motor and a gear as in the first embodiment. The antifouling member may be rotated by an operation from the display / input unit 603.

  [Fourth Embodiment]

  Hereinafter, the difference between the image forming apparatus of the fourth embodiment of the present invention and that of the first embodiment will be described.

  FIG. 19 is a flowchart showing a self-check operation of the non-contact temperature sensor unit 40 executed by the image forming apparatus according to the fourth embodiment.

  Since the processes in steps S101 to S113 in FIG. 19 are the same as those in FIG. 14, the description thereof will not be repeated here.

  If “NO” in the step S111, the contamination degree of the infrared filter 57 is calculated on the basis of the difference between the temperature A and the temperature B in a step S201. In step S203, the correction amount of the measured temperature of the non-contact temperature sensor unit 40 is obtained based on the degree of contamination. Thereafter, the antifouling member is returned to the normal position. Based on the obtained correction amount, the measured temperature of the non-contact temperature sensor unit 40 is corrected.

  [Effects of the embodiment]

  When a non-contact type temperature sensor (thermopile) is used as a fixing temperature detection sensor, if the infrared transmission filter (film) becomes dirty, there is a problem that an error occurs in the detected temperature. According to the present embodiment, the image forming apparatus has a mode for detecting the dirt on the thermopile at a temperature at which the temperature measurement object is kept constant. A movable antifouling member is provided to cover a portion of the infrared filter of the thermopile so as not to get dirty. Dirt is detected based on the output difference between before and after the movement of the antifouling member. If dirt is detected, a warning, a notification that cleaning should be performed, a notification that the sensor or filter should be replaced, power supply is stopped, and the like are performed.

  According to the present embodiment, since the contamination of the non-contact temperature sensor can be detected, damage to the fixing belt and the fixing roller due to high temperature control temperature fluctuation (temperature erroneous detection) due to the contamination can be prevented. be able to.

  [Others]

  A configuration may be adopted in which a member such as a cloth is attached to the back surface of the antifouling member 609 (the surface in contact with the infrared filter 57), and the infrared filter can be simultaneously cleaned when the antifouling member 609 is moved.

  When the antifouling member 609 has a fan shape as described above and the central angle is θ, if the rotation angle of the antifouling member is greater than or equal to θ, the difference in sensor detection values before and after the antifouling member moves increases. preferable.

  It is desirable to return the antifouling member to the initial position after the contamination detection is completed. By returning to the original position, the surface of the clean infrared filter protected by the antifouling member in the normal state is prevented from being contaminated, so that the detection sensitivity can be maintained in a good state.

  In the above embodiment, the antifouling member 609 is rotationally moved. However, the antifouling member 609 may be moved horizontally, or the antifouling member 609 may be removed from the position of the infrared filter.

  It should be noted that all non-contact temperature sensor units 401 to 403 may be provided with a mechanism for detecting dirt, or may be provided with a mechanism for detecting dirt only at a part thereof. .

  In the above-described embodiment, the induction heating type fixing device has been described. However, as the heating method, another heating source such as a halogen lamp may be used, and a roller fixing device, a belt fixing device, a pad fixing device, etc. The present invention can also be applied to a fixing method of the above.

  The image forming apparatus may be any one of a monochrome / color copying machine, a printer, a facsimile machine, and a complex machine (MFP) thereof.

  Further, the processing in the above-described embodiment may be performed by software or by using a hardware circuit.

  In addition, a program for executing the processing in the above-described embodiment can be provided, and the program is recorded on a recording medium such as a CD-ROM, a flexible disk, a hard disk, a ROM, a RAM, and a memory card and provided to the user. You may decide to do it. The program may be downloaded to the apparatus via a communication line such as the Internet.

  In addition, it should be thought that the said embodiment is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram illustrating a configuration of an image forming apparatus according to one embodiment of the present invention. FIG. 2 is a diagram illustrating a cross-sectional configuration of a fixing device 1520 in FIG. 1. FIG. 5 is a diagram showing a schematic concept of a heating roller 1521. 5 is a diagram showing a schematic configuration of a pressure roller 1522. FIG. FIG. 6 is a diagram illustrating a detailed configuration of a central section of a fixing device 1520. It is a top view of arrangement | positioning of each roller of FIG. 4 is a perspective view in which a part of the non-contact type temperature sensor unit 40 is broken. FIG. 2 is a block diagram illustrating a temperature control device provided in the image forming apparatus 1501. FIG. FIG. 4 is a diagram showing a configuration of an antifouling member provided in the non-contact type temperature sensor unit 40. FIG. 10 is a top view of the non-contact type temperature sensor unit 40 in a state where the antifouling member 609 is rotated by a predetermined angle from the state of FIG. 9. It is a figure which shows the detection temperature of a thermopile when a thermopile is dirty. It is a figure which shows the temperature of a heating roller at the time of adjusting temperature with a dirty thermopile. It is a figure which compares the output of the thermopile before and behind rotation of an antifouling member. 5 is a flowchart showing a self-check operation of the non-contact type temperature sensor unit 40 executed by the image forming apparatus 1501. It is a figure which shows the table for determining the stain | pollution | contamination degree of the non-contact-type temperature sensor unit 40 hold | maintained at the image forming apparatus in 2nd Embodiment. 10 is a flowchart illustrating a self-check operation of the non-contact type temperature sensor unit 40 executed by the image forming apparatus according to the second embodiment. It is a figure which shows the relationship between the area of a pollution protection member, and the output of the non-contact-type temperature sensor unit. It is the figure which looked at the non-contact-type temperature sensor unit 40 with which the image forming apparatus in 3rd Embodiment is provided from the infrared transmission filter 57 side. 10 is a flowchart showing a self-check operation of a non-contact temperature sensor unit 40 executed by an image forming apparatus according to a fourth embodiment.

Explanation of symbols

6 Non-contact Thermistor 7 Contact Thermistor 8 Separation Claw 9 Soaking Roller 11 Core Bar 12 Heat Insulating Layer 13 Electromagnetic Induction Heating Layer 14 Elastic Layer 15 Release Layer 21 Core Bar 22 Elastic Layer 25 Release Layer 31 Excitation Coil 32 Core 33 Coil bobbins 40, 401 to 403 Non-contact type temperature sensor unit 41 Temperature sensor board unit 42 Temperature sensor unit mounting plate 1501 Image forming apparatus 1502 Intermediate transfer belt 1503 Secondary transfer roller 1504 Intermediate transfer belt tension roller 1505 Intermediate transfer belt drive roller 1506Y, M, C, K Image forming unit 1507Y, M, C, K Photosensitive drum 1508 Charger 1509 Print head unit 1510 Developer 1511Y, M, C, K Primary transfer roller 1512 Cleaner 1513 Paper discharge tray 1514 Paper discharge roller 1 517 Paper feed cassette 1518 Paper feed roller 1519 AIDC (Image density) sensor 1520 Fixing device 1521 Heating roller 1522 Pressure roller 1523 Magnetic flux generation unit 1530 Secondary transfer area 1531 Fixing NIP area 1540, 1541, 1542 Transport path 1570 Timing roller P Paper

Claims (13)

A temperature detection member that is arranged in a non-contact manner with the measurement object and detects the temperature according to the amount of infrared rays emitted from the measurement object;
A heating source for heating the object to be measured;
In the temperature detection member, an antifouling member that covers a part of the translucent part that makes infrared light incident thereon, and is configured to be movable, and
Detecting means for detecting dirt on the temperature detection member based on the amount of infrared light received by the temperature detection member at a certain point in time and the amount of infrared light received by the temperature detection member after moving the antifouling member; And fixing device. The light transmitting portion of the temperature detecting member has a filter,
The antifouling member is a member that shields infrared rays,
The antifouling member is removed at a predetermined timing or moved to another place of the filter at a predetermined timing to expose an antifouling portion covered by the antifouling member. Fixing device.   The fixing device according to claim 1, wherein the detection unit includes a table for determining a stain amount based on a difference in the amount of received infrared light before and after exposure of a portion covered by the antifouling member.   4. The fixing device according to claim 1, further comprising a correction unit that corrects the detected temperature of the temperature detection member based on the amount of dirt detected by the detection unit.   When the difference between the amount of infrared light received by the temperature detection member at a certain point in time and the amount of infrared light received by the temperature detection member after moving the antifouling member exceeds a predetermined value, the detection means is contaminated. The fixing device according to claim 1, wherein the fixing device is determined to be present.   The fixing device according to claim 1, further comprising a notification unit that notifies the detection unit when it is determined that there is dirt.   The fixing device according to claim 1, further comprising means for stopping the apparatus when the detection means determines that there is dirt. The antifouling member is a fan-shaped member having a predetermined angle with respect to the center of the translucent part,
The fixing device according to claim 1, wherein when the dirt is detected by the detection unit, the antifouling member is rotated by the predetermined angle or more with the center of the light transmitting portion as an axis.   The said antifouling member moves in a dirt detection mode, exposes an antifouling portion underneath, and returns to its original position when the dirt detection mode is canceled. Fixing device. A fixing device according to any one of claims 1 to 9,
An image forming apparatus comprising image forming means for forming an image on a recording medium. A temperature detection sensor that is arranged in a non-contact manner with the measurement object and detects the temperature according to the amount of infrared rays emitted from the measurement object,
An antifouling member that covers a part of the translucent part that makes infrared light incident, and includes an antifouling member configured to be movable,
A temperature detection sensor configured to be able to measure both the amount of received infrared light at a certain point in time and the amount of received infrared light after the antifouling member is moved. A temperature detection member that is arranged in a non-contact manner with the measurement object and detects the temperature according to the amount of infrared rays emitted from the measurement object;
A heating source for heating the object to be measured;
In the temperature detection member, the antifouling member that covers a part of the translucent part that makes infrared rays incident thereon, the fouling member configured to be movable, and a control method of a fixing device comprising:
A detection step of detecting contamination of the temperature detection member based on an infrared light reception amount of the temperature detection member at a certain time and an infrared light reception amount of the temperature detection member after moving the antifouling member; The control method of the fixing device. A temperature detection member that is arranged in a non-contact manner with the measurement object and detects the temperature according to the amount of infrared rays emitted from the measurement object;
A heating source for heating the object to be measured;
In the temperature detection member, the antifouling member that covers a part of the translucent part that makes infrared rays incident thereon, and a control program for a fixing device including the antifouling member configured to be movable,
A detection step for detecting contamination of the temperature detection member based on the amount of infrared light received by the temperature detection member at a certain point in time and the amount of infrared light received by the temperature detection member after the antifouling member is moved is performed on the computer. A fixing device control program to be executed.

Images