CN106842871A

CN106842871A - Fixing device

Info

Publication number: CN106842871A
Application number: CN201710139705.5A
Authority: CN
Inventors: 横山秀治; 河岛裕树
Original assignee: Toshiba Corp; Toshiba TEC Corp
Current assignee: Toshiba Corp; Toshiba TEC Corp
Priority date: 2014-11-27
Filing date: 2015-11-09
Publication date: 2017-06-13
Anticipated expiration: 2035-11-09
Also published as: CN105652626A; JP2016110058A; CN106842871B; JP6579812B2; CN105652626B

Abstract

The invention provides the fixing device for being prevented from IGBT element ruptures.The fixing device of implementation method includes：Band, including ferromagnetic layer；Ferromagnetic plate, be arranged in the band and the ferromagnetic plate curie point of the curie point less than the ferromagnetic layer；Sensing heater, generation is hot in being configured to cause the ferromagnetic layer and the ferromagnetic plate, and the sensing heater includes coil；Driver circuit, is configured to export high frequency electric to the coil, and change the high frequency electric；Temperature sensor, is configured to measure the temperature of the coil；And controller, if the temperature of the coil for passing through the temperature sensor measurement is higher than predetermined value, the controller is configured as controlling the driver circuit to reduce the high frequency electric.

Description

Fixing device

It is on November 9th, 2015, Application No. 201510760493.3, entitled " fixing that the application is the applying date The divisional application of the patent application of device ", entire contents are hereby expressly incorporated by reference.

Technical field

Embodiments of the present invention are related to fixing device.

Background technology

It is currently, there are multi-function printer (Multi Function Peripheral, hereinafter referred to as " MFP ") and beats The image processing systems such as print machine.Image processing system possesses fixing device.Fixing device utilizes electromagnetic induction heating mode (below Referred to as " IH modes ") conductive layer to fixing band is heated.Fixing device determines toner image using the heat of fixing band Shadow is on the recording medium.For example, fixing device possesses clips the fixing band heating assisted parts relative with induced-current generating unit.Sense Induced current generating unit produces magnetic flux by the applying of the high frequency electric from inverter drive circuit.Inverter drive circuit has Standby IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) element.Heating assisted parts makes Flux concentration during electromagnetic induction heating, making the caloric value of fixing band increases.Herein, fixing band is adjusted by Electric control Heating.In order to the temperature (hereinafter referred to as " band temperature ") for keeping fixing band is constant, induced-current generating unit is controlled as perseverance Fixed output.In the case where heating assisted parts is formed by whole magnetic alloy, heating assisted parts loses magnetism if more than curie point, Do not form magnetic circuit.As do not formed, then the load (resistance) of induced-current generating unit is reduced the magnetic circuit of heating assisted parts.Fixing dress The reduction of the load for making the electric current increase in inverter drive circuit flowing just correspond to induced-current generating unit is put, sensing is kept Electric current generating unit is output as constant.Such as making the electric current in inverter drive circuit flowing increases, then due in IGBT element streams Dynamic electric current also increases, so there is a possibility that to make the excessive temperature of IGBT elements to rise, make IGBT element ruptures.

The content of the invention

Problem to be solved by this invention is to provide the damaged fixing device for being prevented from IGBT elements.

The fixing device of first aspect present invention include fixing band, induced-current generating unit, heating assisted parts, determination part with And control unit.Fixing band possesses conductive layer.Induced-current generating unit is relative with the fixing band.It is right that induced-current generating unit has The conductive layer carries out the first coil of electromagnetic induction heating.Heating assisted parts clips the fixing band and is sent out with the induced-current Life portion is relative.Heating assisted parts has the magnetic material of the curie point lower than the conductive layer.It is auxiliary that determination part determines the heating Help the state in portion.Control unit, according to the measurement result of the determination part, is judged as that the heating assisted parts has exceeded curie point In the case of, control reduces the output of the induced-current generating unit.

The fixing device of second aspect present invention includes：Fixing band, possesses conductive layer；Induced-current generating unit, it is and described Fixing band is relative and with the coil that electromagnetic induction heating is carried out to the conductive layer；Heating assisted parts, clips the fixing band It is relative with the induced-current generating unit and with the magnetic material of the curie point lower than the conductive layer；Determination part, determines institute State the state of heating assisted parts；And control unit, according to the measurement result of the determination part, it has been judged as the heating assisted parts In the case of curie point, control reduces the output of the induced-current generating unit, and the induced-current generating unit is used as institute Determination part is stated to play a role.

Brief description of the drawings

Fig. 1 is the side view of the image processing system involved by first embodiment.

Fig. 2 is the side of the control module comprising IH coil units and main body control circuit involved by first embodiment View.

Fig. 3 is the perspective view of the IH coil units involved by first embodiment.

Fig. 4 is the magnetic flux of the main coil involved by first embodiment to fixing band and the magnetic circuit of heating accessory plate Explanatory diagram.

Fig. 5 is shown with the side of the control system for being controlled to main body with IH coil units involved by first embodiment Block diagram.

Fig. 6 is the side view of the major part of the fixing device involved by first embodiment.

Fig. 7 is a flow chart for example of the action for showing the fixing device involved by first embodiment.

Fig. 8 is the side view of the major part of the fixing device involved by second embodiment.

Fig. 9 is the side view of the major part of the fixing device involved by the 3rd implementation method.

Specific embodiment

[first embodiment]

Below, referring to the drawings, the image processing system 10 to first embodiment is illustrated.Additionally, in the various figures, it is right Same composition encloses same symbol.

Fig. 1 is the side view of the image processing system 10 involved by first embodiment.Below as image processing system 10 example is enumerated MFP 10 and is illustrated.

As shown in figure 1, MFP 10 possesses scanner 12, control panel 13 and main part 14.Scanner 12, control panel 13 and main part 14 possess control unit respectively.MFP 10 possesses the control unit i.e. systems control division 100 of blanket each control unit.System System control unit 100 possesses CPU (Central Processing Unit, CPU) 100a, ROM (Read Only Memory, read-only storage) 100b and RAM (Random Access Memory, random access memory) 100c (reference pictures 5).The control unit of the control main part 14 of systems control division 100 is main body control circuit 101 (reference picture 2).

Main body control circuit 101 possesses CPU, ROM and RAM (not shown).Main part 14 possesses feed cassette portion 16, printing Machine portion 18 and fixing device 34 etc..Main body control circuit 101 controls feed cassette portion 16, printer portion 18 and fixing device 34 Deng.

Scanner 12 reads original image.Control panel 13 possesses enter key 13a, display part 13b.For example, enter key 13a Receive the input of user.For example, display part 13b is board-like touch surface.Display part 13b receives the input of user, carries out to user Display.

Feed cassette portion 16 possesses paper feeding cassette 16a, pick-up roller 16b.Paper feeding cassette 16a storage recording mediums are sheet material (sheet) P.Pick-up roller 16b takes out sheet material P from paper feeding cassette 16a.

Paper feeding cassette 16a provides untapped sheet material P.Paper supply tray 17 provides untapped sheet material P using pick-up roller 17a.

Printer portion 18 carries out image and is formed.For example, printer portion 18 carries out the original image read by scanner 12 Image formed.Printer portion 18 possesses intermediate transfer belt 21.Printer portion 18 passes through support roller 40, driven voller 41 and tension force Roller 42 supports intermediate transfer belt 21.Support roller 40 possesses drive division (not shown).Printer portion 18 makes intermediate transfer belt 21 along arrow Head m directions rotate.

Printer portion 18 possesses four groups of images and forms station 22Y, 22M, 22C and 22K.Each image formed station 22Y, 22M, The image that 22C and 22K is used separately as Y (yellow), M (magenta), C (cyan) and K (black) is formed.Image forms station 22Y, 22M, 22C and 22K are configured side by side in the downside of intermediate transfer belt 21 along the direction of rotation of intermediate transfer belt 21.

Printer portion 18 is formed above station 22Y, 22M, 22C and 22K in each image possesses each print cartridge (cartridge) 23Y, 23M, 23C and 23K.Each print cartridge 23Y, 23M, 23C and 23K receive Y (yellow), M (magenta), C (cyan) respectively And the toner of K (black) supply.

Below, as a example by forming station 22Y to the image that the Y (yellow) in station 22Y, 22M, 22C and 22K is formed by each image Citing is illustrated.Additionally, forming station 22M, 22C and 22K to image, the same structures of station 22Y are formed with image due to possessing Into and omit detailed description.

Image forms station 22Y and possesses powered charger 26, exposure scan first 27, developing apparatus 28 and photoreceptor cleaner 29.Powered charger 26, exposure scan first 27, developing apparatus 28 and photoreceptor cleaner 29 are configured in along arrow n directions Around the photosensitive drums 24 of rotation.

Image forms station 22Y and possesses primary transfer roller 30.Primary transfer roller 30 is via intermediate transfer belt 21 and photosensitive drums 24 Relatively.

Image forms station 22Y after making photosensitive drums 24 powered by powered charger 26, is exposed using exposure scan first 27. Image forms station 22Y and forms electrostatic latent image on photoconductive drum 24.Developing apparatus 28 using by toner and carrier is formed pair into The developer for dividing, makes the latent electrostatic image developing in photosensitive drums 24.

Primary transfer roller 30 makes to be formed at the toner image of photosensitive drums 24 and is transferred on intermediate transfer belt 21.Image Form station 22Y, 22M, 22C and 22K and color toner image is formed on intermediate transfer belt 21 using primary transfer roller 30.It is color Color toner image overlaps the toner picture of Y (yellow), M (magenta), C (cyan) and K (black) and is formed successively.It is photosensitive Body cleaner 29 removes the toner for remaining in photosensitive drums 24 after primary transfer.

Printer portion 18 possesses secondary transfer roller 32.Secondary transfer roller 32 is via intermediate transfer belt 21 and the phase of support roller 40 It is right.Secondary transfer roller 32 is by the color toner image on intermediate transfer belt 21 in the lump secondary transfer printing on sheet material P.Sheet material P edges Transport path 33 to be provided from feed cassette portion 16 or manual feed trays 17.

Printer portion 18 possesses via the band cleaner 43 relative with driven voller 41 of intermediate transfer belt 21.Band cleaner 43 exists The toner for residuing in intermediate transfer belt 21 is removed after secondary transfer printing.Additionally, image forming part includes 21, four groups of intermediate transfer belt Image forms station (22Y, 22M, 22C and 22K) and secondary transfer roller 32.

Printer portion 18 possesses contraposition roller 33a, fixing device 34 and distributing roller 36 along transport path 33.Printer portion 18 Possess furcation 37 and upset delivery section 38 in the downstream of fixing device 34.Sheet material P after furcation 37 will be fixed delivers to row Go out portion 20 or upset delivery section 38.In the case of duplex printing, the sheet material P that upset delivery section 38 will be sent from furcation 37 Overturn and convey to the direction of contraposition roller 33a.MFP 10 forms fixing toner image side by side in printer portion 18 on sheet material P Go out to discharge unit 20.

Additionally, MFP 10 is not limited to visualization way of connecting, the quantity of developing apparatus 28 is not limited yet.In addition, MFP 10 Toner can be directly transferred to sheet material P from photosensitive drums 24.

Below, fixing device 34 is described in detail.

Fig. 2 is to include the electromagnetic induction heating coil unit 52 (induced-current generating unit) involved by first embodiment The side view of the control module of (hereinafter referred to as IH coil units 52) and main body control circuit 101 (control unit).Below, by electricity Magnetic induction heating coil unit is referred to as " IH coil units "

As shown in Fig. 2 fixing device 34 possesses fixing band 50, backer roll 51, IH coil units 52, heating accessory plate 69 (ferromagnetic plate), the second coil unit 84 (determination part) and main body control circuit 101.

Fixing band 50 is the endless belt of tubular.It is configured with including gripper pad 53 and generates heat auxiliary in the inner circumferential side of fixing band 50 Help the band internal mechanism 55 of plate 69.

Fixing band 50 stacks gradually heating part i.e. heating layer 50a (conductive layer) and parting (From types on basic unit 50b) layer 50c and formed (reference picture 4).As long as additionally, fixing band 50 possesses heating layer 50a, constructing layer without restriction.

For example, basic unit 50b is formed by polyimide resin (PI).For example, heating layer 50a is by nonmagnetic metal such as copper (Cu) Formed.For example, parting layer 50c is formed by fluororesin such as tetrafluoroethene perfluorinated alkoxy vinyl ether copolymer resins (PFA).

In order to carry out preheating rapidly, fixing band 50 makes heating layer 50a thin layer and reduces thermal capacity.Thermal capacity is small to determine Shadow bands 50 shorten the time required for preheating, and save power consumption.

For example, fixing band 50 makes the thickness of the layers of copper of heating layer 50a be 10 μm to reduce thermal capacity.For example, heating Layer 50a is covered by protective layers such as nickel.The protective layers such as nickel suppress the oxidation of layers of copper.The protective layers such as nickel make the mechanical strength of fixing band 50 Improve.

Additionally, heating layer 50a can be by carrying out electroless nickel plating on the basic unit 50b formed by polyimide resin While carry out copper plating and formed.By carrying out electroless nickel plating, put forward the intensity of being close to of basic unit 50b and heating layer 50a It is high.By carrying out electroless nickel plating, so that the mechanical strength of fixing band 50 is improved.

In addition, the surface of basic unit 50b can be coarse by sandblasting or chemical etching.By the surface for making basic unit 50b Coarse, the intensity of being close to for electroplating the nickel of basic unit 50b and heating layer 50a is further improved.

Furthermore it is possible to make the metal dispersions such as titanium (Ti) in formed basic unit 50b polyimide resin in.By making metal point Dissipate in basic unit 50b, the intensity of being close to for electroplating the nickel of basic unit 50b and heating layer 50a is further improved.

For example, heating layer 50a can be formed by nickel, iron (Fe), stainless steel, aluminium (Al) and silver (Ag) etc..Heating layer 50a Two or more alloys can be used, it is stratiform that can also overlap two or more metals.

Fig. 3 is the perspective view of the IH coil units 52 involved by first embodiment.

As shown in figure 3, IH coil units 52 possess main coil 56 (first coil), the first magnetic core 57 and the second magnetic core 58。

Main coil 56 produces magnetic flux by the applying of high frequency electric.Main coil 56 is configured at the periphery of fixing band 50 Side.Main coil 56 is relative in thickness direction with fixing band 50.Width (hereinafter referred to as " band of the main coil 56 in fixing band 50 Cross direction ") on make length direction consistent.

First magnetic core 57 and the covering main coil 56 of the second magnetic core 58 with the opposition side of the fixing band 50 (hereinafter referred to as " back side Side ").First magnetic core 57 and the second magnetic core 58 suppress the magnetic flux overleaf side leakage that main coil 56 is produced.First magnetic core 57 And second magnetic core 58 make the flux concentration from main coil 56 in fixing band 50.

First magnetic core 57 possesses multiple piece alar parts (piece alar part) 57a.Multiple piece alar part 57a are with along the length of main coil 56 The center line 56d in direction is to be axisymmetrically mutually arranged as staggered.

Second magnetic core 58 is configured at the both sides of the length direction of the first magnetic core 57.Second magnetic core 58 possesses across main coil 56 Both wings multiple two alar parts 58a.

For example, piece alar part 57a and two alar part 58a is by nickel-zinc alloy (Ni-Zn) and manganese-nickel (Mn-Ni) equimagnetic Property material is formed.

The magnetic flux that first magnetic core 57 is produced using multiple piece alar part 57a limitation main coils 56.The magnetic that main coil 56 is produced Flux is mutually limited with center line 56d as axial symmetry by each piece wing of main coil 56.First magnetic core 57 is using multiple piece wings Portion 57a is by the flux concentration from main coil 56 in fixing band 50.

The magnetic flux that second magnetic core 58 is produced using multiple two alar parts 58a limitation main coils 56.The magnetic that main coil 56 is produced Flux is limited by the both wings of the main coil 56 in the both sides of the first magnetic core 57.Second magnetic core 58 utilizes multiple two alar parts 58a in the future Flux concentration from main coil 56 is in fixing band 50.Magnetic flux of the flux concentration power of the second magnetic core 58 than the first magnetic core 57 Concentrated force is big.

Main coil 56 possesses the first wing 56a, the second wing 56b.First wing 56a clips center line 56d and is configured at side.The Two wing 56b clip center line 56d and are configured at opposite side.It is the length side of main coil 56 between the first wing 56a and the second wing 56b To inner side, be formed with window portion 56c.

For example, main coil 56 uses twisted wire.Twisted wire is by by insulating materials i.e. heat-resistant polyamide acid imide cladding Many of copper wire material tie up and formed.Main coil 56 is formed around the coil of electric conductivity.

As shown in Fig. 2 main coil 56 makes magnetic flux by the applying of the high frequency electric from inverter drive circuit 68 Produce.For example, inverter drive circuit 68 possesses IGBT, and (Insulated Gate Bipolar Transistor, insulated gate is double Bipolar transistor) element 68a and MOSFET (Metal Oxide semiconductor field effect Transistor, mos field effect transistor) switch element such as element (not shown).IGBT elements 68a with MOSFET element is connected.(ON)/disconnection (OFF) is alternately connected by by IGBT elements 68a and MOSFET element, makes high-frequency electrical Stream flows in main coil 56.Flowed in main coil 56 by making high frequency electric, so as to produce high frequency magnetic around main coil 56 .By the magnetic flux of above-mentioned high frequency magnetic field, vortex flow is produced in the heating layer 50a of fixing band 50.By above-mentioned vortex flow and The resistance of heating layer 50a, produces Joule heat.By the generation of above-mentioned Joule heat, fixing band 50 is heated.

For example, being constant during the connection of IGBT elements 68a.Change by during the connection for making MOSFET element, from And the high frequency electric change flowed in main coil 56.With the change of the high frequency electric flowed in main coil 56, electromagnetism sense The exporting change that should be heated.

Heating accessory plate 69 is configured in the inner circumferential side of fixing band 50.From bandwidth direction observation, heating accessory plate 69 along The inner peripheral surface of fixing band 50 is formed as circular shape.Heating accessory plate 69 clips fixing band 50 and relative with main coil 56.Heating Accessory plate 69 has the magnetic material (strong magnetic material) of the curie point less than heating layer 50a.The magnetic produced by main coil 56 Flux, magnetic flux is produced between heating accessory plate 69 and fixing band 50.By the generation of above-mentioned magnetic flux, in fixing band 50 Heating layer 50a produces Joule heat.By the generation of above-mentioned Joule heat, the heating of the fixing band 50 of main coil 56 is aided in.

The two ends of the heating circular shape of accessory plate 69 are by base station support (not shown).The radial outer side of heating accessory plate 69 From away from the inner peripheral surface of fixing band 50.For example, between the radial outer side and the inner peripheral surface of fixing band 50 of heating accessory plate 69 At intervals of 1mm~2mm or so.Additionally, the radial outer side of heating accessory plate 69 can contact the inner peripheral surface of fixing band 50.

For example, the length of the heating accessory plate 69 on bandwidth direction is more than the length by paper areas on bandwidth direction (hereinafter referred to as " sheet material is wide ").Additionally, sheet material it is wide be the roomy sheet material of most short side in the sheet material for using width.For example, sheet material is wide Short side less times greater than A3 paper is wide.

Fig. 4 is the magnetic flux of the main coil 56 involved by first embodiment to fixing band 50 and heating accessory plate 69 The explanatory diagram of magnetic circuit.

As shown in figure 4, the magnetic flux that main coil 56 is produced forms the first magnetic circuit of the heating layer 50a sensings of fixing band 50 81.First magnetic circuit 81 is formed as surrounding first wing 56a and the second wing 56b of main coil 56.First magnetic circuit 81 passes through the first magnetic The magnetic core 58 of core 57 and second, heating layer 50a.In addition, the magnetic flux that main coil 56 is produced forms the heating sensing of accessory plate 69 Second magnetic circuit 82.The radial direction (hereinafter referred to as " band radially ") that second magnetic circuit 82 is formed in fixing band 50 is abutted with the first magnetic circuit 81 Position.Second magnetic circuit 82 is by accessory plate 69 and the heating layer 50a of generating heat.

Heating accessory plate 69 by iron, nickel alloy that curie point is 220 DEG C~230 DEG C etc. whole magnetic alloy thin sheet of metal Part is formed.Heating accessory plate 69 loses magnetism if more than curie point.Specifically, heating accessory plate 69 is as exceeded curie point Then become by ferromagnetism and turn to paramagnetism.Heating accessory plate 69 does not form the second magnetic circuit 82 if more than curie point, does not aid in being fixed With 50 heating.Heating accessory plate 69 is formed by by whole magnetic alloy, with curie point as boundary, fixing band can be aided in during low temperature 50 intensification, and the excessive temperature rise of fixing band 50 can be suppressed during high temperature.

Herein, the heating of fixing band 50 controls the Electric control of circuit 67 and is adjusted by IH.For retainer belt temperature For constant, IH coil units 52 are controlled as constant output.In the case where heating accessory plate 69 is formed by whole magnetic alloy, hair Hot accessory plate 69 is lost magnetism if more than curie point, and the second magnetic circuit 82 is not formed.If do not formed the second magnetic circuit 82, then IH coils The load (resistance) of unit 52 is reduced.

IH controls circuit 67 to just correspond to the negative of IH coil units 52 in the electric current increase that inverter drive circuit 68 flows The reduction of load, keeps IH coil units 52 to be output as constant.Such as inverter drive circuit 68 flowing electric current increase, then by Also increase in the electric current flowed in IGBT elements 68a, therefore existing makes the excessive temperature of IGBT elements 68a rise, make IGBT units Part 68a damaged possibility.Therefore in the present embodiment, as described later, inferred by determining the resistance of the second coil 84a The heat treatment of heating accessory plate 69.Then, IH controls circuit 67 control IH coil units 52, so that in the above-mentioned resistance for determining The output reduction of electromagnetic induction heating during less than threshold value.

Additionally, heating accessory plate 69 can be by the gauge sheet metal components shape that possesses the magnetic properties such as iron, nickel and stainless steel Into.In addition, heating accessory plate 69 such as possesses magnetic properties, then can be formed by resin comprising Magnaglo etc..In addition, heating Accessory plate 69 can be formed by following magnetic material (ferrite).Magnetic material (ferrite) passes through faradic magnetic flux simultaneously Promote the heating of fixing band 50.If exposed to faradic magnetic flux, itself does not also generate heat magnetic material (ferrite).Hair Hot accessory plate 69 is not limited to thin-plate member.

As shown in Fig. 2 cover (shield) 76 is configured in the inner circumferential side of heating accessory plate 69.Cover 76 is formed as auxiliary with heating The circular shape for helping plate 69 same.Be supported on base station (not shown) at the two ends of circular shape by cover 76.Additionally, cover 76 can be propped up Support heating accessory plate 69.For example, cover 76 is formed by nonmagnetic substances such as aluminium and copper.The blocking of cover 76 is from IH coil units 52 Magnetic flux.Cover 76 suppresses measure voltage of flux effects thermistor etc..

Gripper pad 53 is the press section that the inner circumferential of fixing band 50 is pressed towards the side of backer roll 51.In fixing band 50 and pressurization Clamping part 54 is formed between roller 51.Gripper pad 53 has the clamping for forming clamping part 54 between fixing band 50 and backer roll 51 Portion forms face 53a.Clamping part forms face 53a and is bent to form convex in the inner circumferential side of fixing band 50 from bandwidth direction observation.Clamping Portion forms face 53a and is bent along the outer peripheral face of backer roll 51 from bandwidth direction observation.

For example, backer roll 51 possesses silicon sponge and silicone rubber layer of heat resistance etc. around core iron.For example, adding The surface configuration of pressure roller 51 has parting layer.Parting layer is formed by fluorine-type resins such as PFA resins.Backer roll 51 utilizes pressing mechanism pair Fixing band 50 pressurizes.Backer roll 51 is the pressurization part to the pressurization of fixing band 50 together with gripper pad 53.

As fixing band 50 and the driving source of backer roll 51, a motor 51b is provided with.Motor 51b is by main body The motor drive circuit 51c of the control control of circuit 101 drives.Motor 51b is via first gear row (not shown) and pressurization Roller 51 is connected.Motor 51b is (not shown) with band driver part via second gear row and mono-directional overrun clutch to be connected Connect.Backer roll 51 is rotated according to motor 51b along arrow q directions.It is fixing when fixing band 50 and backer roll 51 are abutted Band 50 is driven in backer roll 51, is rotated along arrow u direction.When fixing band 50 and backer roll 51 deviate from, fixing band 50 is by electricity Motivation 51b rotates along arrow u direction.Additionally, fixing band 50 can also possess driving source independently of backer roll 51.

Central thermistor 61 and the measuring band temperature of edge thermistor 62.Measurement result with temperature is input to master Body controls circuit 101.Central thermistor 61 is configured in bandwidth direction inner side.Edge thermistor 62 is matched somebody with somebody in bandwidth direction Put in the heating region of IH coil units 52 and non-by paper areas.The control IH of main body control circuit 101 coil units 52, with Make edge thermistor 62 determine with temperature more than threshold value when stop the output of electromagnetic induction heating.Fixing band 50 The non-excessive temperature rise by paper areas when stopped by making the output of electromagnetic induction heating, so as to prevent the damage of fixing band 50 Wound.

Main body control circuit 101 is according to central thermistor 61 and the measure knot with temperature of edge thermistor 62 Really, IH control circuits 67 are controlled.IH control circuits 67 drive electricity by the control of main body control circuit 101 to converter The size of the high frequency electric of the output of road 68 is controlled.Fixing band 50 keeps various according to the output of inverter drive circuit 68 Control temperature range.IH control circuits 67 possess CPU, ROM and RAM (not shown).

Thermostat 63 plays a role as the safety device of fixing device 34.Thermostat 63 is abnormal in fixing band 50 Heating, temperature are acted when rising to blocking threshold value.By the action of thermostat 63, the electric current of IH coil units 52 is flowed to It is interrupted.By flowing to the blocking of the electric current of IH coil units 52, MFP 10 stops driving, and suppresses the abnormal hair of fixing device 34 Heat.

Below, the control system 110 of the IH coil units 52 to making fixing band 50 generate heat is described in detail.

Fig. 5 is shown with the control system 110 for being controlled to main body of the IH coil units 52 involved by first embodiment Block diagram.

As shown in figure 5, control system 110 possess systems control division 100, main body control circuit 101, IH circuits 120 and Motor drive circuit 51c.

Control system 110 provides electric power using IH circuits 120 to IH coil units 52.IH circuits 120 possess rectification circuit 121st, IH controls circuit 67, inverter drive circuit 68 and current sense circuit 122.

IH circuits 120 are transfused to electric current via relay 112 from AC power 111.IH circuits 120 lead to the electric current of input Over commutation circuit 121 carries out rectification and is supplied to inverter drive circuit 68.Situation of the relay 112 in cut-out thermostat 63 Lower electric current of the blocking from AC power 111.Inverter drive circuit 68 possesses the driving IC 68b of IGBT elements 68a.IH is controlled Circuit processed 67 enters according to central thermistor 61 and the measurement result with temperature of edge thermistor 62 to driving IC 68b Row control.The IH control controls of circuit 67 drive IC 68b, and control the output of IGBT elements 68a.Current sense circuit 122 will The measurement result of the output of IGBT elements 68a sends to IH and controls circuit 67.IH controls circuit 67 according to current sense circuit 122 IGBT elements 68a output measurement result, to drive IC 68b be controlled so that IH coil units 52 are output as perseverance It is fixed.

Main body control circuit 101 obtains measured value R (reference picture 7) described later from resistance measuring circuit 84b.Main body control electricity Road 101 controls IH coil units 52 according to measured value R.Main body control circuit 101 judges whether measured value R is less than threshold value Rt.It is main Body controls circuit 101 according to above-mentioned result of determination, carry out the driving of fixing device 34 continuation and IH coil units 52 it is defeated The control of any one of the reduction for going out.Additionally, the reduction of the output of IH coil units 52 includes the stopping of IH coil units 52.

Fig. 6 is the side view of the major part of the fixing device 34 involved by first embodiment.

As shown in fig. 6, the second coil unit 84 possesses the second coil 84a, resistance measuring circuit 84b (resistance measurement portion). Second coil unit 84 determines whether heating accessory plate 69 is in the state for having exceeded curie point.Second coil 84a and main coil 56 splits are constituted.Second coil 84a is produced by the magnetic field of the accessory plate 69 that generates heat by being powered.For example, the second coil 84a is used The coil of twisted wire.Resistance measuring circuit 84b determines the resistance of the second coil 84a.The measurement result of the resistance of the second coil 84a It is input to main body control circuit 101.

Below, in the circumferential direction (hereinafter referred to as " band circumferential direction ") of fixing band 50 in the accessory plate 69 that generates heat, will be clipping The region relative with IH coil units 52 of fixing band 50 is set to to region 69a.The end 69c of heating accessory plate 69 is that heating is auxiliary The end with circumferential direction of plate 69 is helped, it is to be adjacent to the region to region 69a.The end 69c of heating accessory plate 69 is in band Fixing band 50 is not clipped on the direction of footpath relative with IH coil units 52.

In addition, the end 52c of IH coil units 52 is the end with circumferential direction of the first magnetic core 57 and the second magnetic core 58, It is included to the region protruded inwardly with footpath side.

Second coil 84a is configured in the region S1 (reference relative and not relative with main coil 56 with heating accessory plate 69 Fig. 2).Specifically, region S1 is located between the end 52c of IH coil units 52 and fixing band 50 with footpath direction.Region S1 Be with circumferential direction from the outside of main coil 56 to heating accessory plate 69 end 69c scope.Region S1 band circumferential direction with The end 52c of IH coil units 52 is relative and to clip fixing band 50 relative with the end 69c of the accessory plate 69 that generates heat.In the S1 of region One end (medial extremity) with circumferential direction is on the side with footpath direction between the end 52c and main coil 56 of IH coil units 52 Boundary.The other end (outboard end) of the bandwidth direction in the S1 of region is clipping fixing band 50 in face of heating accessory plate 69 with footpath direction The front end (two ends of circular shape) of end 69c.

In the present embodiment, the second coil 84a is configured in the outer circumferential side of fixing band 50.Second coil 84a clips fixed Shadow bands 50 are relative with the end 69c of heating accessory plate 69.

Additionally, the second coil 84a can clip fixing band 50 in scope not relative with main coil 56 being aided in heating Plate 69 to relative to region 69a.

Second coil 84a leaves appointed interval and is fixed with fixing band 50.Second coil 84a bandwidth direction at least with It is relative by paper areas.For example, the second coil 84a is relative with the central portion of fixing band 50.

Size of the size of the second coil 84a less than main coil 56.Because the second coil 84a is produced by being powered leading to The magnetic field of heating accessory plate 69 is crossed, resistance measuring circuit 84b can determine the resistance of the second coil 84a.

Additionally, with make the size of the second coil 84a it is equal with main coil 56 more than situation compared with, can be by the second line Circle 84a is easily configured at above-mentioned zone S1.

The magnetic flux that second coil 84a is produced forms the 3rd magnetic circuit 85 of the heating layer 50a sensings of fixing band 50.3rd magnetic Road 85 passes through heating layer 50a.In addition, the magnetic flux that the second coil 84a is produced exceedes curie point and loses in heating accessory plate 69 Before magnetic, the 4th magnetic circuit 86 of the heating sensing of accessory plate 69 is formed.4th magnetic circuit 86 is formed in band footpath direction and the 3rd magnetic The adjoining position of road 85.4th magnetic circuit 86 is by accessory plate 69 and the heating layer 50a of generating heat.The resistance of the second coil 84a is with hair The change of the magnetic of hot accessory plate 69 and change.That is, the resistance of the second coil 84a is according to whether forming the 4th magnetic circuit 86 and becoming Change.

Flowed in the second coil 84a by making faint high frequency electric (hereinafter referred to as " high frequency weak current "), can Determine the resistance of the second coil 84a.For example, in the upstream side of the second coil 84a and downstream connection resistance measuring circuit 84b, Current value in upstream side and downstream according to the second coil 84a determines above-mentioned resistance.Additionally, high frequency weak current is than becoming The weak electric current of high frequency electric of the output of parallel operation drive circuit 68.

Then, reference picture 7 a, example to the action of the fixing device 34 involved by first embodiment is said It is bright.

Fig. 7 is a flow chart for example of the action for showing the fixing device 34 involved by first embodiment.

In Act100, resistance measuring circuit 84b flows high frequency weak current in the second coil 84a.For example, the faint electricity of high frequency Flow is frequency 60kHz, electric current 10mA.

In Act101, resistance measuring circuit 84b determines the resistance of the second coil 84a.In the present embodiment, surveyed with resistance The resistance for determining the second coil 84a that circuit 84b is measured to is " measured value R ".Main body control circuit 101 is from resistance measuring circuit 84b obtains measured value R.

Additionally, main body control circuit 101 can obtain measured value R by other circuits via logic circuit etc..

In Act102, main body control circuit 101 judges whether the measured value R obtained in Act101 is less than threshold value Rt (examples Such as 1 [Ω]).

According to following reason, by judging that whether measured value R, less than threshold value Rt, can interpolate that the magnetic of heating accessory plate 69 Change.

In the case that measured value R is more than threshold value Rt, heating accessory plate 69 has ferromagnetism more than curie point.Heating auxiliary Plate 69 have it is ferromagnetic in the case of, the second coil 84a produce magnetic flux formed the 3rd magnetic circuit 85 and the 4th magnetic circuit 86.

On the other hand, less than in the case of threshold value Rt, heating accessory plate 69 exceedes curie point and becomes and turn to paramagnetic measured value R Property.In the case of heating accessory plate 69 is changed into paramagnetic, the 4th magnetic circuit 86 is lost.

Therefore, by whether judging measured value R less than threshold value Rt, can conclude that the heat treatment of heating accessory plate 69.

Main body control circuit 101 (Act102 is yes) when being judged to that measured value R is less than threshold value Rt enters treatment Act104.Main body control circuit 101 enters treatment in the case where judging measured value R in more than threshold value Rt (Act102 is no) Enter Act103.

In Act103, fixing device 34 continues to drive.For example, fixing device 34 is carrying out continuing through paper and preheating In the case of contour output driving, continue height output and drive.

In Act104, main body control circuit 101 controls IH coil units 52 according to measured value R.According to following reason, carry out The control of the main body control circuit 101 based on measured value R.

In Act105, main body control circuit 101 determines whether to stop IH coil units 52 according to measured value R.For example, main body Control circuit 101 is judged to stop IH coil units 52 in the case where measured value R is less than 0.5 [Ω].Main body control circuit 101 In the case where being judged to stop IH coil units 52 (Act105 is yes), end treatment.Main body control circuit 101 is by stopping IH coil units 52, the excessive temperature for suppressing IGBT elements 68a rises.Main body control circuit 101 is by suppressing IGBT elements 68a Excessive temperature rise, prevent the breakage of IGBT elements 68a.

Main body control circuit 101 (Act105 is no) in the case where being judged to not stop IH coil units 52, makes treatment Into Act106.

In Act106, the output of the reduction IH of main body control circuit 101 coil units 52.For example, main body control circuit 101 drops The low electric power provided to IH coil units 52.Main body control circuit 101 suppresses IGBT by reducing the output of IH coil units 52 The excessive temperature of element 68a rises.Main body control circuit 101 is risen by suppressing the excessive temperature of IGBT elements 68a, is prevented The breakage of IGBT elements 68a.

In Act103, fixing device 34 continues to drive in the state of the output of IH coil units 52 is lowered.

The action of the fixing device 34 when below to preheating is illustrated.

As shown in Fig. 2 during preheating, fixing device 34 makes fixing band 50 be rotated to arrow u direction.IH coil units 52 pass through The applying of the high frequency electric of inverter drive circuit 68, magnetic flux is produced in the side of fixing band 50.

For example, during preheating, making fixing band 50 from backer roll 51 away from the state of, make fixing band 50 to arrow u direction Rotation.During preheating, rotated away from the state of from backer roll 51 by making fixing band 50, play following effect.With make to be fixed Compared with 50 situations about having been rotated in the state of backer roll 51 has been abutted, the pressurized roller 51 of heat of fixing band 50 can be avoided Seize.Seized by the pressurized roller 51 of the heat for avoiding fixing band 50, preheating time can be shortened.

Additionally, during preheating, in the state of backer roll 51 has been abutted fixing band 50, by making backer roll 51 to arrow q Direction rotates, and can make fixing band 50 to the driven rotation of arrow u direction.

As shown in figure 4, IH coil units 52 are heated using the first magnetic circuit 81 to fixing band 50.The profit of heating accessory plate 69 The heating of fixing band 50 is aided in the second magnetic circuit 82.By aiding in the heating of fixing band 50, promote rapidly pre- of fixing band 50 Heat.

As shown in Fig. 2 IH controls circuit 67 according to the survey with temperature of central thermistor 61 or edge thermistor 62 Determine result, control inverter drive circuit 68.Inverter drive circuit 68 provides high frequency electric to main coil 56.

The action of the fixing device 34 when below, to fixing operation is illustrated.

Fixing band 50 reach fixing temperature and terminate preheating after, make backer roll 51 abut fixing band 50.Make pressurization Roller 51 has been abutted in the state of fixing band 50, is rotated to arrow q directions by making backer roll 51, and makes fixing band 50 to arrow u The driven rotation in direction.When such as being required in the presence of printing, then MFP 10 (reference picture 1) starts printing.MFP 10 passes through printer Portion 18 forms toner image on sheet material P, and sheet material P is delivered into fixing device 34.

MFP 10 make to be formed with the sheet material P of toner image by reach fixing temperature fixing band 50 and backer roll 51 it Between clamping part (nip) 54.Be fixed on toner image on sheet material P by fixing device 34.Carrying out fixing period, IH control electricity Road 67 controls IH coil units 52, and fixing band 50 is maintained at into fixing temperature.

By fixing operation, fixing band 50 seizes heat by sheet material P.For example, in the case of passing through paper with high-speed and continuous, Because the heat seized by sheet material P is very big, therefore the fixing band 50 of low heat capacity can not be maintained at fixing temperature sometimes.Second magnetic The heating deficiency of the auxiliary compensation with caloric value of the fixing band 50 on road 82.Even if the heating auxiliary of the fixing band 50 of the second magnetic circuit 82 Fixing temperature is maintained at band temperature is also made when continuing through paper with high speed.

However, it is believed that in order to prevent the breakage of IGBT elements 68a, it is necessary to set the heat of the temperature for determining IGBT elements 68a Quick resistance.Thermistor is installed in not IGBT elements 68a but in the housing of inverter drive circuit 68 in itself.In temperature-sensitive In the case that the temperature of resistance measurement IGBT elements 68a rises, main body control circuit 101 drives fan coolling IGBT elements 68a. According to thermistor, the slow temperature that can determine IGBT elements 68a rises.But, with thermistor measure temperature drastically It is difficult that degree rises, and there is limit in the temperature tracing ability of IGBT elements 68a.Further, since thermistor is installed in shell In body, therefore it is difficult that the correct temperature of IGBT elements 68a is determined in thermistor.Using the IGBT units of thermistor Internal temperature of the temperature of the measurement of part 68a sometimes with actual IGBT elements 68a deviates from.In addition, in the IGBT units using fan Under the cooling of part 68a, the inside for being cooled to IGBT elements 68a is difficult, and sufficiently cool IGBT elements 68a there is also limit. So as under the temperature measuring using thermistor and the cooling using fan, existing can not prevent breaking for IGBT elements 68a The possibility of damage.

In this regard, according to first embodiment, resistance measuring circuit 84b determines the resistance of the second coil 84a.By determining the The resistance of two coil 84a, the slow temperature that can indirectly determine IGBT elements 68a rises and temperature rising drastically. By determining the resistance of the second coil 84a, compared with the situation of above-mentioned thermistor is set, can determine in real time indirectly The temperature of IGBT elements 68a.In addition, the resistance by determining the second coil 84a, in above-mentioned actual IGBT elements 68a Portion's temperature away from not being a problem.

In addition, main body control circuit 101 obtains the resistance (measured value R) of the second coil 84a from resistance measuring circuit 84b. The control IH coil units 52 when measured value R is less than threshold value of main body control circuit 101, so that the output drop of electromagnetic induction heating It is low.When measured value R is less than threshold value by reducing the output of electromagnetic induction heating, the temperature mistake of IGBT elements 68a can be suppressed Degree rises.Specifically, main body control circuit 101 judges whether measured value R is less than threshold value Rt.Threshold value Rt is less than in measured value R In the case of, main body control circuit 101 can reduce the output of IH coil units 52.For example, by stopping IH coil units 52 Or the output of reduction IH coil units 52, the excessive temperature rising of IGBT elements 68a can be suppressed.Thus, it is possible to prevent IGBT The breakage of element 68a.

In addition, be made up of the second coil 84a and the split of main coil 56, resistance measuring circuit 84b can at any time determine the The resistance of two coil 84a.Therefore, main body control circuit 101 can at any time obtain measured value R.

In addition, being configured at the area relative and not relative with main coil 56 with heating accessory plate 69 by by the second coil 84a Domain S1, obtains following effect.Compared with the situation that the second coil 84a is configured at the region relative with main coil 56, due to The second coil 84a can be suppressed to be influenceed by the very big magnetic force of main coil 56, therefore, it is possible to accurately determine the second coil The resistance of 84a.

In addition, clip fixing band 50 by the second coil 84a (being adjacent to to area with the end 69c of heating accessory plate 69 The position of domain 69a) it is relative, obtain following effect.Second coil unit 84 can with to region 69a equal temperature The position (with the position to the temperature change to region 69a with correlation) of change determines the resistance of the second coil 84a.

In addition, at least relative with by paper areas in bandwidth direction by the second coil 84a, the second coil unit 84 and The non-resistance that the second coil 84a can be separately determined by paper areas.Therefore, main body determines circuit 101 with non-by paper Opening region can obtain measured value R with distinguishing.

[second embodiment]

Then, second embodiment is illustrated according to Fig. 8.Additionally, pair with the same mode of first embodiment enclose same symbol Number omit the description.

Fig. 8 is the side view of the major part of the fixing device 234 involved by second embodiment.Additionally, Fig. 8 is suitable In the side view of Fig. 6.

As shown in figure 8, the fixing device 234 involved by second embodiment does not possess involved by first embodiment Two coil 84a.Fixing device 234 involved by second embodiment is possessing this point using the determination part 284 of main coil 56 It is different from above-mentioned first embodiment.Additionally, representing resistance measuring circuit in Fig. 8 symbols 284b.

IH coil units 52 have the main coil 56 (coil) that electromagnetic induction heating is carried out to heating layer 50a.IH coil lists Unit 52 plays a role as determination part 284.Determination part 284 is produced by the accessory plate 69 that generates heat by the energization to main coil 56 Magnetic field.Determination part 284 determines the resistance of main coil 56.

The magnetic flux that main coil 56 is produced forms the first magnetic circuit 81 and the second magnetic circuit 82.The resistance of main coil 56 is with hair The heat treatment of hot accessory plate 69 and change.

Flowed in main coil 56 by making high frequency weak current, the resistance of main coil 56 can be determined.

Resistance measuring circuit 284b determines the resistance of main coil 56.In the present embodiment, by resistance measuring circuit 284b The resistance of the main coil 56 for determining is used as " measured value R ".Main body control circuit 101 obtains measure from resistance measuring circuit 284b Value R.

Whether the measured value R that the judgement of main body control circuit 101 is obtained is less than threshold value Rt (such as 1 [Ω]).

In the case that measured value R is more than threshold value Rt, heating accessory plate 69 has ferromagnetism no more than curie point.Heating Accessory plate 69 have it is ferromagnetic in the case of, main coil 56 produce magnetic flux formed the first magnetic circuit 81 and the second magnetic circuit 82.

On the other hand, less than in the case of threshold value Rt, heating accessory plate 69 exceedes curie point and is changed into paramagnetic measured value R Property.In the case of heating accessory plate 69 is changed into paramagnetic, the second magnetic circuit 82 is lost.

The control IH of main body control circuit 101 coil units 52, so as to make electromagnetism when the measured value R for obtaining is less than threshold value Rt The output reduction of sensing heating.

According to second embodiment, the effect same with first embodiment is obtained.

In addition, clipping fixing band 50 compared with the relative situations of end 69c of heating accessory plate 69 with the second coil 84a Compared with the resistance in face of main coil 56 can be determined to the place to region 69a.Therefore, it is possible to judge to the magnetic to region 69a The change of property.

In addition, in the timing (timing) for not making IH coil units 52 generate heat, the resistance of main coil 56 can be determined.Example Such as, when paper is continued through and when preheating outside operation during etc. (such as often pass through 10, paper), master can be determined The resistance of coil 56.Therefore, during operation, can interpolate that the change to the magnetic to region 69a.

In addition, compared with by the situation that the second coil 84a is constituted with the split of main coil 56, due to component count can be cut down Amount, can simplify the composition of fixing device 234.

Additionally, in the timing for making IH coil units 52 generate heat, the resistance of main coil 56 can be determined.For example, continuously leading to When crossing paper and during preheating, the resistance of main coil 56 can be determined.By determining when paper is continued through and when preheating The resistance of main coil 56, can be in face of the resistance to the place the real time measure main coil 56 to region 69a.Therefore, continuous Being capable of change of the real-time judge to the magnetic to region 69a during by paper and when preheating.

[the 3rd implementation method]

Then, the 3rd implementation method is illustrated according to Fig. 9.Additionally, pair with the same mode of first embodiment enclose same symbol Number omit the description.

Fig. 9 is the side view of the major part of the fixing device 334 involved by the 3rd implementation method.Additionally, Fig. 9 is suitable In the side view of Fig. 6.

As shown in figure 9, the fixing device 334 involved by the 3rd implementation method does not possess involved by first embodiment Two coil 84a.Fixing device 334 involved by 3rd implementation method is in the second line for possessing the inner circumferential side for being configured at fixing band 50 This point for enclosing 384a is different from above-mentioned first embodiment.Second coil 384a is configured in the radially inner side of heating accessory plate 69 (than the assisted parts 69 closer to the radially inner side of fixing band that generates heat).Additionally, in Fig. 9, symbol 384 represents the second coil unit, symbol Number 384b represents resistance measuring circuit.

The magnetic flux that second coil 384a is produced formed heating before heating accessory plate 69 loses magnetism more than curie point 5th magnetic circuit 87 of the sensing of accessory plate 69.5th magnetic circuit 87 does not stretch out to the band footpath direction outside of heating accessory plate 69 and passes through hair Hot accessory plate 69.

In addition, the situation that the magnetic flux that the second coil 384a is produced exceedes curie point and lose magnetism in heating accessory plate 69 Under, form the 6th magnetic circuit 88 of the heating layer 50a sensings of fixing band 50.6th magnetic circuit 88 to heating accessory plate 69 band footpath direction Outside is stretched out, and by heating layer 50a.The resistance of the second coil 384a becomes with the change of the magnetic of heating accessory plate 69 Change.

Flowed in the second coil 384a by making high frequency weak current, the resistance of the second coil 384a can be determined.

Resistance measuring circuit 384b determines the resistance of the second coil 384a.In the present embodiment, by resistance measuring circuit The resistance of the second coil 384a that 384b is determined is used as " measured value R ".Main body control circuit 101 takes from resistance measuring circuit 384b Obtain measured value R.

Whether main body control circuit 101 judges the measured value R for having obtained less than threshold value Rt (such as 1 [Ω]).

According to following reason, by judging measured value R whether less than threshold value Rt such that it is able to judge heating accessory plate 69 The change of magnetic.

In the case that measured value Rt is more than threshold value Rt, heating accessory plate 69 has ferromagnetism no more than curie point.Hair Hot accessory plate 69 have it is ferromagnetic in the case of, the second coil 384a produce magnetic flux formed the 5th magnetic circuit 87.

On the other hand, in the case where measured value R is less than threshold value Rt, heating accessory plate 69 exceedes curie point and is changed into paramagnetic Property.In the case of heating accessory plate 69 is changed into paramagnetic, the magnetic flux that the second coil 384a is produced forms the 6th magnetic circuit 88.This Outward, in the case of heating accessory plate 69 is changed into paramagnetic, the 5th magnetic circuit 87 is lost.

According to the 3rd implementation method, the effect same with first embodiment is obtained.

In addition, inside by the footpath that second coil 384a is configured at into heating accessory plate 69 in the inner circumferential side of fixing band 50 Side, obtains following effect.It is configured at compared with the situation of the outer circumferential side of fixing band 50 with by the second coil 84a, can be by second Coil 384a collects in the inner circumferential side of fixing band 50 together with heating accessory plate 69.

The fixing device of at least one implementation method in accordance with the above, due to the temperature of IGBT elements 68a can be suppressed Degree of spending rises, therefore, it is possible to prevent the breakage of IGBT elements 68a.

Additionally, above-mentioned heating layer 50a can also be formed by magnetic materials such as nickel.

In addition, above-mentioned determination part is not limited to possess resistance measurement portion.For example, determination part can include that measure heating is auxiliary Help the temperature measuring portion of the temperature of plate 69.For example, temperature measuring portion temperature in use sensor.By determining heating accessory plate 69 Temperature, can directly judge whether heating accessory plate 69 exceedes curie point.That is, determination part can determine the shape of heating accessory plate 69 State.

In addition, above-mentioned main body control circuit 101 is not limited to be sentenced indirectly according to the measurement result of resistance measuring circuit Whether disconnected heating accessory plate 69 exceedes curie point.For example, measure knot of the main body control circuit 101 according to said temperature sensor Really, can directly judge whether heating accessory plate 69 exceedes curie point.That is, main body control circuit 101 is according to said determination portion Measurement result judge heating accessory plate 69 exceed curie point in the case of, control reduce the output of IH coil units.

The function of the fixing device in above-mentioned implementation method can be realized with computer.At this time it is also possible to pass through to use Recorded in the recording medium of embodied on computer readable in the program for realizing the function, and program on the recording medium will be recorded Perform and realize in reading computer system.Additionally, " computer system " signified herein includes the hardware such as OS, external equipment. In addition, so-called " recording medium of embodied on computer readable " refer to the removable medium such as floppy disk, photomagneto disk, ROM, CD-ROM and The storage devices such as the hard disk being built in computer system.Also, so-called " recording medium of embodied on computer readable " can also be wrapped Include：In short-term as via the communication line in the case of the transmission program of the communication wire such as the networks such as internet, telephone wire road The medium of interior dynamically holding program；And as constituted server, the volatilization of the inside computer system of client computer now Property memory keeps the medium of program within a certain period of time like that.In addition, said procedure can be for realizing above-mentioned function A part program, can also be by the combination with the program being already recorded in computer system to realize above-mentioned functions Program.

Several embodiments of the invention is illustrated, but what these implementation methods were only proposed as an example, It is not intended to be defined the scope invented.These implementation methods can be carried out in other various modes, not departed from In the range of the purport of invention, various omissions, replacement, change can be carried out.These implementation methods and its deformation be contained in hair Bright scope or purport are same, belong to the invention described in technical scheme and the scope being equal to it.

Symbol description

The fixing device of 10 image processing system 34,234,334

50 fixing band 50a heating layers (conductive layer)

52IH coil units (induced-current generating unit)

56 main coils (coil, first coil)

69 heatings accessory plate (heating assisted parts)

84th, 384 second coil unit (determination part)

The main body control circuit (control unit) of the second coil of 84a, 384a 101

284 determination part S1 regions.

Claims

1. a kind of fixing device, it is characterised in that including：

Band, including ferromagnetic layer；

Ferromagnetic plate, be arranged in the band and the ferromagnetic plate curie point of the curie point less than the ferromagnetic layer；

Sensing heater, generation is hot in being configured to cause the ferromagnetic layer and the ferromagnetic plate, and the sensing heater includes line Circle；

Driver circuit, is configured to export high frequency electric to the coil, and change the high frequency electric；

Temperature sensor, is configured to measure the temperature of the coil；And

Controller, if the temperature of the coil for passing through the temperature sensor measurement is higher than predetermined value, the control Device processed is configured as controlling the driver circuit to reduce the high frequency electric.

2. fixing device according to claim 1, it is characterised in that the predetermined value refers to the Curie of the ferromagnetic plate Point.

3. fixing device according to claim 1, it is characterised in that the coil is in the width in the band with the band Degree direction on paper by the corresponding position in region at.

4. fixing device according to claim 1, it is characterised in that

The driver circuit includes switch element, and the switch element includes that igbt and metal oxide are partly led Body field-effect transistor；And

The controller reduces the height by extending the turn-on time of the mos field effect transistor Frequency electric current.

5. a kind of fixing device, it is characterised in that including：

Band, including ferromagnetic layer；

Measuring unit, is configured as output to indicate whether the temperature of the ferromagnetic plate exceedes the signal of predetermined value；And

Controller, the controller is configured as：

Receive the signal from measuring unit output；

Whether the temperature for judging the ferromagnetic plate based on the signal exceedes the predetermined value；And

If the temperature of the coil exceedes the predetermined value, the driver circuit is controlled to reduce the high frequency electric.

6. fixing device according to claim 5, it is characterised in that the predetermined value refers to the Curie of the ferromagnetic plate Point.

7. fixing device according to claim 5, it is characterised in that the coil is in the width in the band with the band Degree direction on paper by the corresponding position in region at.

8. fixing device according to claim 5, it is characterised in that

9. fixing device according to claim 5, it is characterised in that the measuring unit is temperature sensor.

10. fixing device according to claim 5, it is characterised in that

The measuring unit includes：

Second coil, is oriented to be in close proximity to the ferromagnetic plate；And

Resistance measurement circuit, is configured to measure the resistance of second coil, and the resistance of second coil is with described The increase of the temperature of the second coil and reduce.

11. fixing devices according to claim 5, it is characterised in that the measuring unit includes being configured as measuring institute The resistance measurement circuit of the resistance of coil is stated, the resistance of the coil subtracts with the increase of the temperature of the coil It is few.

A kind of 12. fixing devices, it is characterised in that including：

Band, including ferromagnetic layer；

Driver circuit, is configured to export high frequency electric to the coil, and by switching switching on and off for switch element And change the high frequency electric；

Controller, the controller is configured as：

Receive the signal from measuring unit output；

13. fixing devices according to claim 12, it is characterised in that the predetermined value refers to the residence of the ferromagnetic plate In point.

14. fixing devices according to claim 12, it is characterised in that the coil is in the band in the band Paper on width by the corresponding position in region at.

15. fixing devices according to claim 12, it is characterised in that

16. fixing devices according to claim 12, it is characterised in that the measuring unit is temperature sensor.

17. fixing devices according to claim 12, it is characterised in that the measuring unit includes：

18. fixing devices according to claim 12, it is characterised in that the measuring unit includes being configured as measuring institute The resistance measurement circuit of the resistance of coil is stated, the resistance of the coil subtracts with the increase of the temperature of the coil It is few.