CN1782921A - Image heating device and image forming apparatus using the same - Google Patents
Image heating device and image forming apparatus using the same Download PDFInfo
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- CN1782921A CN1782921A CN 200510126774 CN200510126774A CN1782921A CN 1782921 A CN1782921 A CN 1782921A CN 200510126774 CN200510126774 CN 200510126774 CN 200510126774 A CN200510126774 A CN 200510126774A CN 1782921 A CN1782921 A CN 1782921A
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Abstract
An image heating device having a predetermined heat generation rate with a low current. The device comprises a heating roller (1) having magnetism and conductivity, an exciting coil (5) opposed to the peripheral face of the heating roller (1) and adapted for allowing the heating roller (1) to produce heat with electromagnetic induction. The exciting coil (5) is composed of a bundle of sixty copper wires of a 0.2 mm diameter are extended toward the rotary shaft of the heating roller (1) and they are circumferentially wound along the circumferential direction of the heating roller (1). The bundled wires are arranged in close contact to each other in the circumferentially direction of the heating roller (1) so as to cover the upper half of the heating roller (1).
Description
The application is dividing an application of following application:
Denomination of invention: image heating and adopt the image processing system of this device
Application number: 00807125.X
The applying date: on February 19th, 2000
Technical field
The present invention relates to be applicable in image processing systems such as electro-photography apparatus, electrostatic recording apparatus, use to photographic fixing image not carry out photographic fixing fixing device image heating and adopt the image processing system of this image heating.
Background technology
As this image heating, the known spy of having opens the pattern that flat 10 No. 74007 communiques, spies open flat 7 No. 295414 disclosed employing electromagnetic induction such as communique.
Open in flat 10 No. 74007 communiques the spy,, recorded and narrated and a kind of coil has been wrapped in field coil on the iron core as the excitation unit that is used to produce electromagnetic induction.In Figure 34, the sectional drawing of the disclosed image heating of this communique is shown.
In Figure 34, the 310th, the coil of generation high frequency magnetic field, the 311st, the metal sleeve that when generating heat, rotates because of induction heating.312 are provided in a side of the internal pressurization member of the inside of metal sleeve 311.In addition, 313 are provided in a side of the external pressurized member of the outside of metal sleeve 311, and external pressurized member 313 rotates along the direction of arrow a among the figure, and metal sleeve 311 rotates with the rotation of external pressurized member 313.
Be loaded with the recording chart 314 that the not conduct of photographic fixing toner picture is recorded material, shown in the arrow among the figure, be transported to roll gap portion.Then, utilize the heat of metal sleeve 311 and the pressure of two pressing elements 312,313, the not photographic fixing toner on the recording chart 314 is looked like to carry out photographic fixing.
Coil 310 has the 310a of winding portion, the 310b of a plurality of separation.The 310a of these winding portions, 310b form around the 315b of iron core column portion, the 315d by lead being wrapped in the iron core 315 that has a plurality of iron core column 315a～315e of portion with multi-turn across not shown insulating component.Here, iron core 315 is made of the ferrite as magnetic material, and forms the magnetic circuit of the magnetic flux that is produced by the alternating current that puts on coil 310.
, open in flat 10 No. 74007 disclosed image heatings of communique, should consider problem as described below above-mentioned spy.
That is, in the structure of above-mentioned excitation unit since with Wire-wound in the iron core column portion of iron core 315, so the configuration of lead will be subjected to the restriction of position of the iron core column portion of iron core.Therefore, when the configuration lead, just limited the degree of freedom in the design, be difficult in circumferentially going up along side face of metal sleeve 311 simultaneously with wide amplitude configuration lead.
On the other hand, open in flat 7 No. 295414 communiques, recording and narrating a kind of structure for conductive coil is configured in excitation unit on the insulating supporting body by spiral fashion the spy.In Figure 35, the sectional drawing of the disclosed image heating of this communique is shown, in Figure 36, be illustrated in the oblique view of the heater coil that uses in this image heating.
As shown in figure 35, warm-up mill 201 is rotating with the direction along arrow among the figure when backer roll 202 contacts, and 202 rotations with warm-up mill 201 of backer roll are rotated.And backer roll 202 rotates in the mode that compresses with warm-up mill 201 drivenly.In addition, be loaded with the toner picture of not photographic fixing and the recording chart of between two rollers 201,202, carrying 203, between two rollers 201,202, be heated pressurization, thereby the not photographic fixing toner on the recording chart 203 is looked like to carry out photographic fixing.
Open the structure of flat 7 No. 295414 described excitation units of communique according to this spy, open the structure of the excitation unit of flat 10 No. 74007 communiques compares with above-mentioned spy, the suffered restriction of degree of freedom during the configuration lead in the design reduces, and lead can be configured on the circumferencial direction of warm-up mill 201 along side face with wide amplitude.
But, open in flat 7 No. 295414 disclosed image heatings of communique above-mentioned spy, exist problem as described below.
That is, because heater coil 204 is that conducting film is disposed by spiral fashion, so between electric current, exist the space that does not have electric current to flow through by coiled coil.Therefore, shown in the dotted line S among Figure 35, magnetic flux between each coil by forming little loop.And in this case, can not be with magnetic flux with high efficient guiding warm-up mill 201, thereby the magnetic flux that does not connect warm-up mill 201 is increased.Therefore, in order to obtain to make the required power of warm-up mill 201 heatings, must make big electric current flow through heater coil 204.And be to make big electric current flow through heater coil 204, at the parts of induction heating, thereby induction heating will be increased with the cost of power supply with the anti-big electric current of just necessary use in the power supply.
Further, as being the image heating of representative with the heat fixing device, generally adopting the image heating of Contact Heating modes such as hot-rolling formula, belt in the past.
In recent years, according to shortening heat time heating time and energy-conservationly wait requirement, a kind of belt type apparatus that can set thermal capacity very little more and more noticeable (open put down 6 No. 318001 communiques etc. with reference to the spy).
In Figure 37, be illustrated in the sectional drawing that the spy opens disclosed belt image heating in flat 6 No. 318001 communiques.As shown in figure 37, the non junction that rotating annular photographic fixing band 401 is suspended on fixing roller 402 and the warm-up mill 403, by the heating source H1 of the inside that is configured in warm-up mill 403 warm-up mill 403 is heated, thereby photographic fixing band 401 is heated to the temperature of regulation.
In this image heating,, can realize agonic photographic fixing with the structure of not oiling by adopting the little photographic fixing band 403 of thermal capacity.
In also comprising the general belt image heating of above-mentioned conventional example, thus have the thermal capacity of photographic fixing band can be set the very little advantage that can shorten heat time heating time, therefore, can make the photographic fixing band itself be warmed up to the temperature of regulation at short notice.But on the other hand, thermal capacity is more little, is easy to make the temperature of photographic fixing band to descend to such an extent that low-down tendency is also strong more in that toner is captured heat because of recording chart etc. during as photographic fixing.Therefore, before arriving photographic fixing portion once more, for the photographic fixing band temperature stabilization that can carry out reliable photographic fixing, must make reducing and return to necessary temperature equably.
Further, the reduction that also exists photographic fixing band temperature when the having passed through photographic fixing portion problem that great changes will take place along with the state of temperature of used member in the recording chart of this moment and the pressue device etc.Therefore, regardless of these state of temperatures, promptly no matter how big the reduction by the photographic fixing band temperature after the photographic fixing portion have difference, all must make photographic fixing band temperature return to the uniform temperature that is suitable for photographic fixing most when arriving photographic fixing portion once more all the time, so that carry out stable photographic fixing.
For making photographic fixing band temperature stabilization and returning to the temperature of regulation equably, the heat transfer structure from heat generating part to the photographic fixing band and the structure of heat generating part itself thereof are vital, but in existing belt image heating this point are not carried out special consideration.
In addition, in also comprising the general belt image heating of above-mentioned conventional example, set the thermal capacity of photographic fixing band very little for shortening heat time heating time, but therefore exist the excessive problem of non-uniform temperature and local heating.When using size than image heating during at the little recording chart (recording chart that width is narrow) of the size of the depth direction (the turning axle direction of warm-up mill 403) of Figure 37 continuously, it is more remarkable that this problem will become.Promptly, recording chart pass through part, capture heat and must correspondingly heat because of continuously being recorded paper, but the part of not passing through when recording chart is when being heated too, because the thermal capacity of heater (heat generating roller) is little thereby temperature will continuously rise.So, when temperature anomaly rises,, then will produce thermal deviation as under this state, using large-sized recording chart (recording chart that width is big).
On the contrary, when for preventing that thermal deviation from limiting adstante febre, be recorded paper and captured the part of heat and will become low temperature, thereby may produce cold deviation, maybe can not carry out photographic fixing.
Disclosure of an invention
The present invention is to develop for the above-mentioned problem that solves prior art, its objective is that providing a kind of can obtain the image heating of regulation thermal value and adopt the image processing system of this image heating with little electric current.Another object of the present invention is to, a kind of image heating that uses the photographic fixing band is provided, promptly can shorten heat time heating time and can stably control the image heating of photographic fixing band temperature and adopt the image processing system of this image heating.
For achieving the above object, the 1st structure of image heating of the present invention, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component, in this image heating, above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, and make at the upwardly extending wire harness in the turning axle side of above-mentioned generating component and be close to mutually at a position at least.According to the 1st structure of this image heating,, compared with prior art can make magnetic flux connect generating component expeditiously because the magnetic flux that is produced by the alternating current that flows through field coil can not be passed through between wire harness.Therefore, obtaining to need not to make big electric current to flow through field coil when making the required power of generating component heating.
In addition, in the 1st structure of the image heating of the invention described above, preferably make wire harness many in the axial both ends of the rotation of the generating component number of plies more overlapping than central portion.According to this preferred example, can evenly heat the axial wideer scope of the rotation of generating component.In addition, at the overlapping wire harness in the axial both ends of the rotation of generating component, and the distance between the generating component increases, so, can not make vortex flow concentrate on this part and cause local temperature too high.
In addition, in the 1st structure of image heating of the present invention, the external diameter that preferably makes wire rod be 0.1mm above, below the 0.3mm, and to make the external diameter of wire harness be below the 5mm.According to this preferred example, can reduce the resistance of wire harness, so can suppress the heating of field coil to high-frequency ac current.In addition, owing to can make wire harness have suitable thickness, rigidity and permanance, institute is so that field coil is easy to formation.
In addition, in the 1st structure of the image heating of the invention described above, be preferably more than the 10 μ H, below the 50 μ H at the inductance of the above-mentioned field coil under the field coil state relative with generating component, resistance be preferably 0.5 Ω above, below 5 Ω.According to this preferred example, only need to constitute field circuit by the so not high circuit component of anti-electric current, proof voltage, can obtain generating component enough input power and thermal value.
In addition, in the 1st structure of the image heating of the invention described above, preferably also have the iron core that constitutes by magnetic material in the outside of field coil.According to this preferred example, the magnetic flux of the rear side of field coil is all passed through, from the inside of iron core so can prevent that magnetic flux from rearward leaking.Consequently, the heating that the electromagnetic induction because of the electroconductive member of periphery causes can be prevented, unwanted irradiation of electromagnetic waves can be prevented simultaneously.In addition, owing to strengthened the inductance of field coil, thereby the electromagnetic coupled between field coil and the generating component is improved, so even with identical coil current also can be bigger to the generating component input power.In addition, in this case, what preferably make iron core rotates axial length than the axial length weak point of the rotation of above-mentioned generating component along generating component.According to this preferred example, the vortex flow density that can prevent the generating component end face uprises and makes generating component end face excessive heating.In addition, in this case, preferably make the generating component of field coil peripheral part rotate the width that be recorded material of axial length, and make the generating component of iron core rotate the width that be recorded material of axial length greater than employed breadth extreme greater than employed breadth extreme.According to this preferred example,, also can make from the magnetic field that field coil is radiated generating component and become even in the turning axle direction of generating component even the coiling of field coil exists to a certain degree inhomogeneous.Therefore, can make and be recorded the heating of material by the generating component of part and distribute and to become even.According to this configuration, the Temperature Distribution in the photographic fixing portion is become evenly, thereby can obtain stable photographic fixing effect.In addition, can also the heating that makes generating component distribute become the axial length of rotation that reduces generating component uniformly simultaneously and field coil rotate axial length along generating component.Consequently, miniaturization that can implement device also can reduce cost.In addition, in this case, preferably make from the iron core end face to the generating component end face to rotate axial distance along above-mentioned generating component longer than the relative spacing above-mentioned iron core and the generating component.According to this preferred example, make from iron core and be not concentrated in narrow and small scope to the magnetic line of force of generating component end direction radiation, so can prevent induction current concentrate on generating component end face and near, thereby can prevent the overheating of end windings and parts of generating component.In addition, in this case, preferably make iron core have obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component.According to this preferred example, the magnetic flux that produced by the alternating current that flows through field coil (coil current) is passed through between opposed and generating component, so that the major part of magnetic circuit can constitute by high permeability materials.Therefore, by the low air part of the magnetoconductivity that magnetic flux passed through that coil current produces, be the close gap part between generating component and the iron core.So, the inductance of field coil is increased, and the generating component that can almost all lead by the magnetic flux that coil current produces.Consequently, the electromagnetic coupled between generating component and the field coil is further improved, even thereby with identical coil current also can be bigger to the generating component input power.Further, limit with generating component by opposed because of magnetic circuit, so can carry out freely designing of magnetism circuit.In this case, further, generating component preferably utilizes the supporting member that is made of magnetic material to support, and the interval between above-mentioned supporting member and the iron core is preferably more than 2 times of relative spacing between above-mentioned iron core and the above-mentioned generating component.According to this preferred example, connect the magnetic flux of iron core, can not be directed to supporting member, and make its most of generating component that connects.Therefore, the electromagnetic energy of supplying with field coil generating component can be delivered to expeditiously, the heating of supporting member can be prevented simultaneously.In this case, further, length between the end of axial outermost end is rotated along above-mentioned generating component by magnetic conduction portion, preferably rotates length between the end of axial outermost end less than opposed portion along above-mentioned generating component.According to this preferred example, can the opposed portion that guarantees to determine the heat generating part scope rotate axial scope along generating component in reduce the material use amount of magnetic conduction portion, become even so can heating be distributed with the lower structure of cost.In this case, further, at least a portion of opposed portion is formed near portion more near generating component than magnetic conduction portion.According to this preferred example, can be to the bigger power of generating component input.In this case, further, preferably be provided with a plurality of near portion and make above-mentioned a plurality of middle position that is positioned at the field coil coiling near a position in the portion.Because the magnetic flux that is produced by coil current must pass through from the central authorities of field coil coiling, so be positioned at this part generating component that can lead expeditiously by the magnetic flux that coil current produces by making near portion.In addition, in this case, preferably make at least a portion of iron core on the turning axle direction of generating component, have the gap.According to this preferred example,, can design heating freely and distribute by changing the configuration mode of iron core.In addition, even adopted under the situation of small size iron core at a low price, also still can obtain even temperature and distribute.Further, can simultaneously,, can promote to dispel the heat from the gap heat radiation of iron core because the surface area of iron core itself is increased.In this case, further, preferably make iron core have obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component, and preferably uneven on the turning axle direction that is distributed in above-mentioned generating component in the gap of the above-mentioned magnetic conduction portion of above-mentioned iron core.Further, in this case, it is narrower than central portion preferably to make the gap of the magnetic conduction portion of iron core rotate axial end at generating component.According to this preferred example, the Temperature Distribution of generating component is become evenly, thereby can prevent that photographic fixing is bad.In this case, further, preferably make iron core have obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative, and be asymmetric position the center line that the above-mentioned opposed portion of above-mentioned iron core is configured to rotate with respect to above-mentioned generating component axial field coil with above-mentioned generating component.According to this preferred example, use less iron core that the axial heating of rotation of generating component is distributed and become even.On the contrary, if the iron core of equivalent then can make heating distribute and become more even.In this case, further, preferably make iron core have obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component, and the gap of above-mentioned opposed portion that makes above-mentioned iron core on the turning axle direction of above-mentioned generating component less than the gap of the above-mentioned magnetic conduction portion of above-mentioned iron core.According to this preferred example, can in the core length of the opposed portion that guarantees to determine the heat generating part scope, reduce the material use amount of magnetic conduction portion, so, even the core material amount also can make heating distribute and becoming even than in the past still less and be low-cost configuration.In this case, further, preferably make iron core have obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component, and the above-mentioned opposed portion that makes above-mentioned iron core on the turning axle direction of above-mentioned generating component continuously.According to this preferred example,, also can make from opposed magnetic field that arrives generating component and become even in the turning axle direction even gap and skewness are set on the iron core of magnetic conduction portion.According to this configuration, can in the iron core that reduces magnetic conduction portion, make to be recorded the heating of material by the generating component on the part and to distribute and become evenly, so that the temperature in the photographic fixing portion becomes even.Therefore, can obtain stable photographic fixing effect.In addition, can also distribute to become in the heating that makes generating component and reduce the iron core of magnetic conduction portion uniformly simultaneously, so the miniaturization of energy implement device makes cost reduce simultaneously.In addition, in this case, preferably generating component is formed tubulose, and make above-mentioned generating component inside perpendicular to the basal area of the face of turning axle maximum basal area less than iron core and field coil.According to this preferred example, generating component that can thermal capacity is little, the field coil that the number of turns is many, an amount of ferrite (iron core) are used in combination.Therefore, can be when suppressing the thermal capacity of fixing device with the coil current of regulation to the bigger power of generating component input.In addition, in this case, preferably the part of iron core is cut apart and constituted movable part, and above-mentioned movable part is remained and can move with respect to other parts of above-mentioned iron core.In this case, further, preferably make to be positioned at the employed movable part that is recorded the outside in the zone that material passes through and to move with respect to other parts of iron core.According to this preferred example, the excessive temperature that can prevent to be recorded the scope that material do not pass through rises, and can prevent that the temperature of members such as the photographic fixing band of end and bearing from surpassing heat resisting temperature.In addition, even undersizedly use large scale to be recorded material after being recorded material using continuously, the temperature of photographic fixing portion is still normal, so can prevent the generation of thermal deviation.Therefore, undersizedly can and then use large-sized material that is recorded after being recorded material using.
In addition, in the 1st structure of the image heating of the invention described above, preferably also have the shading member that constitutes by conductive material of at least a portion at the back side that covers field coil.According to this preferred example, can prevent from inside and outside device, to propagate from the frequency electromagnetic waves that field coil produces.According to this configuration, can prevent that the inside and outside circuit of locking apparatus because of electromagnetic noise misoperation takes place.
In addition, in the 1st structure of the image heating of the invention described above, preferably also have cooling device with airflow cooling field coil.
In addition, in the 1st structure of the image heating of the invention described above, preferably also have the heat insulating component of the transmission of between field coil and generating component, covering heat.According to this preferred example, can cool off field coil and do not cool off generating component.In addition, in this case, the outside at field coil preferably also has the iron core that is made of magnetic material, and make above-mentioned field coil along generating component rotate axial length than heat insulating component along above-mentioned generating component rotate axial length short but than above-mentioned iron core to rotate axial length along above-mentioned generating component long.According to this preferred example,, iron core rises even when the generating component, also preventing the temperature of iron core.
In addition, in the 1st structure of the image heating of the invention described above, preferably also have fixing roller, be suspended on the photographic fixing band on above-mentioned fixing roller and the generating component.In addition, in this case, the outside at field coil preferably also has the iron core that is made of magnetic material, above-mentioned iron core preferably has not by above-mentioned field coil and relative with above-mentioned generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component, and make above-mentioned opposed portion rotate between the end of axial outermost end length less than the width of photographic fixing band along above-mentioned generating component.According to this preferred example, can be not overheated owing to do not captured the generating component of the part of heat by the photographic fixing band, thus can prevent the overheating of end windings and parts of generating component,
In addition, the 2nd structure of image heating of the present invention, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component, this image heating is characterised in that: above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, at the axial both ends of the rotation of above-mentioned generating component, make wire harness more than the number of plies of the overlapping coiling of central portion.
In addition, the 3rd structure of image heating of the present invention, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: the outside at above-mentioned field coil also has the iron core that is made of magnetic material, and make above-mentioned iron core rotate the width that be recorded material of axial length along above-mentioned generating component greater than employed breadth extreme.
In addition, the 4th structure of image heating of the present invention, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component, this image heating is characterised in that: in the side opposite with above-mentioned generating component with respect to the above-mentioned field coil outside, also have relative by having not of constituting of magnetic material opposed and by above-mentioned field coil and the iron core of the magnetic conduction portion relative with above-mentioned generating component with above-mentioned generating component by above-mentioned field coil, and at least a portion that makes above-mentioned opposed portion forms near generating component near portion more than above-mentioned magnetic conduction portion, makes at least a portion of above-mentioned iron core have the gap simultaneously on the turning axle direction of generating component.
In addition, the 5th structure of image heating of the present invention, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component, this image heating is characterised in that: in the side opposite with above-mentioned generating component with respect to the above-mentioned field coil outside, also have relative by having not of constituting of magnetic material opposed and by above-mentioned field coil and the iron core of the magnetic conduction portion relative with above-mentioned generating component with above-mentioned generating component by above-mentioned field coil, and make above-mentioned opposed with the relative area of above-mentioned generating component basal area perpendicular to the circumferencial direction of generating component greater than above-mentioned magnetic conduction portion.According to the 5th structure of this image heating, the electromagnetic coupled between field coil and the generating component is improved, thereby heating efficiency is improved.In addition, owing to make the flux concentrating that produces by coil current in the opposed portion of iron core, so by make opposed with the relative area of generating component basal area perpendicular to the circumferencial direction of generating component greater than magnetic conduction portion, can make the axial thermal value of rotation of generating component become even.Further, can guarantee when magnetic flux is by basal area the gap to be set on iron core, thereby on field coil, form not relative part,, can prevent that magnetic flux is to external leaks simultaneously so can promote heat radiation from field coil with iron core.
In addition, the 6th structure of image heating of the present invention, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: in the side opposite with above-mentioned generating component with respect to the above-mentioned field coil outside, also have the iron core that constitutes by magnetic material, the part of iron core is cut apart and constituted movable part, and above-mentioned movable part is remained and can move with respect to other parts of above-mentioned iron core.
In addition, the 7th structure of image heating of the present invention is characterized in that: have the photographic fixing band, form the pressue device of roll gap portion, at least a portion is constituted and hung in a movable manner above-mentioned photographic fixing band by conductive material heat generating roller with the crimping of above-mentioned photographic fixing band and in the face side of above-mentioned photographic fixing band, dispose and carry out the field coil that excitation heats to above-mentioned heat generating roller with contact site above-mentioned photographic fixing band across the side face of above-mentioned photographic fixing band and above-mentioned heat generating roller is relative.According to the 7th structure of this image heating,, surpass necessary temperature so the temperature of heat generating roller need not be elevated to owing to heat and its heat is delivered to the photographic fixing band immediately at the contact site with the photographic fixing band of heat generating roller.Consequently, heat time heating time can be shortened.
In addition, in the 7th structure of the image heating of the invention described above, the excitation width of the moving direction of photographic fixing band is substantially equal to or less than the contact width of above-mentioned photographic fixing band and heat generating roller.According to this preferred example,, therefore can prevent the abnormal ascending of heat generating roller temperature because the scope that contacts with the photographic fixing band on the heat generating roller is generated heat.
In addition, in the 7th structure of the image heating of the invention described above, preferably also have and contact with surface beyond heat generating roller and the contact site photographic fixing band and the temperature-detecting device of detected temperatures and control the control device of the output of field coil according to the output of said temperature pick-up unit.According to this preferred example, the temperature of photographic fixing band can be remained at the temperature that is suitable for photographic fixing most.
In addition, in the 7th structure of the image heating of the invention described above, preferably field coil is applied the exciting current with assigned frequency, and the electroconductive member of heat generating roller is had greater than the thickness by the skin depth of its material and the decision of afore mentioned rules frequency.According to this preferred example, the induction current major part is produced in heat generating roller.
In addition, the 8th structure of image heating of the present invention is characterized in that: have the photographic fixing band, with the crimping of above-mentioned photographic fixing band and the face side of above-mentioned photographic fixing band form roll gap portion pressue device, by the magnetic material that Curie temperature is set at setting constitute and hang in a movable manner above-mentioned photographic fixing band heat generating roller, be located at electroconductive member in the above-mentioned heat generating roller, dispose and carry out the field coil that excitation heats with contact site above-mentioned photographic fixing band across the side face of above-mentioned photographic fixing band and above-mentioned heat generating roller is relative above-mentioned heat generating roller.According to the 8th structure of this image heating,, surpass necessary temperature so the temperature of heat generating roller need not be elevated to owing to heat and its heat is delivered to the photographic fixing band immediately at the contact site with the photographic fixing band of heat generating roller.Consequently, heat time heating time can be shortened.
In addition, in the 8th structure of the image heating of the invention described above, preferably electroconductive member to be set with the heat insulation mode of heat generating roller.According to this preferred example, make the heat that produces in the heat generating roller be difficult to be delivered to electroconductive member.
In addition, in the 8th structure of the image heating of the invention described above, preferably field coil is applied the exciting current with assigned frequency, and heat generating roller is had greater than the thickness by the skin depth of its material and the decision of afore mentioned rules frequency.
In addition, the 9th structure of the image heating of the invention described above, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the outer peripheral face of above-mentioned generating component, in this image heating, above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, and make at the upwardly extending wire harness in the turning axle side of above-mentioned generating component and be close to mutually at a position at least.
In addition, the 10th structure of the image heating of the invention described above, have the generating component that constitutes by rotor with magnetic and electric conductivity, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the outer peripheral face of above-mentioned generating component, this image heating is characterised in that: above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, at the axial both ends of the rotation of above-mentioned generating component, make wire harness more than the number of plies of the overlapping coiling of central portion.
In addition, the 11st structure of image heating of the present invention, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: the outside at above-mentioned field coil also has the iron core that is made of magnetic material, and make above-mentioned iron core rotate the width that be recorded material of axial length along above-mentioned generating component greater than employed breadth extreme.
In addition, the structure of image processing system of the present invention, have make be recorded on the material form and be loaded with not the image of photographic fixing image form the unit, and with above-mentioned not photographic fixing image at the above-mentioned fixing device that is recorded photographic fixing on the material, this image processing system is characterised in that: the image heating of the invention described above is used as above-mentioned fixing device.
The simple declaration of accompanying drawing
Fig. 1 is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 1st example.
Fig. 2 is the sectional plan view of expression as the heat generating part of the fixing device of the image heating of the present invention's the 1st example.
Fig. 3 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 1st example.
Fig. 4 is the equivalent circuit diagram of expression as the heat generating part of the fixing device of the image heating of the present invention's the 1st example.
Fig. 5 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 2nd example.
To be expression remove the backplan of the heat generating part behind the heat generating roller as the fixing device of the image heating of the present invention's the 2nd example to Fig. 6.
Fig. 7 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 3rd example.
Fig. 8 is the sectional drawing of expression as another routine heat generating part of the fixing device of the image heating of the present invention's the 3rd example.
Fig. 9 is that expression will be used as the sectional drawing of the image processing system of fixing device as the image heating of the present invention's the 4th example.
Figure 10 A is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 4th example.
Figure 10 B is expression another routine sectional drawing as the fixing device of the image heating of the present invention's the 4th example.
The perspective view of Figure 11 heat generating part that to be expression look from the direction of the arrow G of Figure 10 A.
Figure 12 is expression as the sectional drawing of the heat generating part of the face at the center of the turning axle that is comprising heat generating roller of the fixing device of the image heating of the present invention's the 4th example and field coil.
Figure 13 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 4th example.
Figure 14 is the sectional drawing of expression as the heat generating roller of the fixing device of the image heating of the present invention's the 4th example.
Figure 15 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 5th example.
Figure 16 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 6th example.
Figure 17 perspective view that to be expression look from the direction of the arrow A of Figure 16 as the heat generating part of the fixing device of the image heating of the present invention's the 6th example.
Figure 18 is expression another routine perspective view as the heat generating part of the fixing device of the image heating of the present invention's the 6th example.
Figure 19 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 7th example.
Figure 20 perspective view that to be expression look from the direction of the arrow A of Figure 19 as the heat generating part of the fixing device of the image heating of the present invention's the 7th example.
Figure 21 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 8th example.
Figure 22 perspective view that to be expression look from the direction of the arrow A of Figure 21 as the heat generating part of the fixing device of the image heating of the present invention's the 8th example.
Figure 23 is the perspective view of expression as the heat generating part of the fixing device of the image heating of the present invention's the 9th example.
Figure 24 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 9th example.
Figure 25 is expression another routine sectional drawing as the heat generating part of the fixing device of the image heating of the present invention's the 9th example.
Figure 26 is that expression will be used as the sectional drawing of the image processing system of fixing device as the image heating of the present invention's the 10th example.
Figure 27 is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 10th example.
Figure 28 is the sectional drawing of the photographic fixing band that uses in the fixing device of expression as the image heating of the present invention's the 10th example.
Figure 29 is the field coil that uses in the fixing device of expression as the image heating of the present invention's the 10th example and the front elevation of core.
Figure 30 is the sectional drawing of the heat generating roller that uses in the fixing device of expression as the image heating of the present invention's the 10th example.
Figure 31 is the figure of the magnetic flux flow of the heat generating roller that uses by the fixing device as the image heating of the present invention's the 10th example when being used for low-temperature condition is described.
Figure 32 is the figure of the magnetic flux flow of the heat generating roller that uses by the fixing device as the image heating of the present invention's the 10th example when being used for the condition of high temperature is described.
What Figure 33 was expression as the image heating of the present invention's the 11st example carries out the sectional drawing of the fixing device of photographic fixing to color image.
Figure 34 is the sectional drawing of the image heating of expression prior art.
Figure 35 is another routine sectional drawing of the image heating of expression prior art.
Figure 36 is the oblique view of the heater coil that uses in another example of image heating of expression prior art.
Figure 37 is the sectional drawing of another example of the image heating of expression prior art.
The optimal morphology that is used to carry out an invention
Below, be described more specifically the present invention with example.
[the 1st example]
Fig. 1 is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 1st example, and Fig. 2 is the sectional plan view of the heat generating part of this fixing device of expression.
In Fig. 1, Fig. 2, the 1st, as the heat generating roller of generating component, the 2nd, the supporting side plate that constitutes by galvanized steel plain sheet, the 3rd, be fixed in supporting side plate 2 and with the bearing of rotating mode at the two supports heat generating roller.Heat generating roller 1 is rotated by the drive unit driving of not shown device body.Heat generating roller 1 is made of the magnetic material as iron-nickel-chromium, and its Curie point is adjusted into more than 300 ℃.In addition, heat generating roller 1 is by the tubulose formation of thick 0.3mm.
On the surface of heat generating roller 1, be covered with the release layer (not shown) of the thick 20 μ m that constitute by fluorine resin, so that it has release property.In addition, as release layer, also can be used alone or as a mixture PTFE, PFA, FEP, silicon rubber, contain good resin or the rubber of release property such as fluororubber.When heat generating roller 1 is used for the photographic fixing of monochrome image, only guarantee that release property gets final product, but, then preferably make it have elasticity as heat generating roller 1 being used for the photographic fixing of color image, in this case, must further form thick rubber layer.
The 4th, as the backer roll of pressue device.This backer roll 4 is that the silicon rubber of JISA65 degree constitutes by hardness, is crimped on the heat generating roller 1 and forms roll gap portion with the snap-in force of 20kgf.So in this state, backer roll 4 rotates with the rotation of heat generating roller 1.In addition, as the material of backer roll 4, also can use other heat stable resin or rubber as containing fluororubber, fluorine resin and so on.In addition, on the surface of backer roll 4, preferably cover resin or rubber such as PFA, PTFE, FEP separately or, to improve its wearing quality and release property with mixing.In addition, for preventing heat leakage, backer roll 4 preferably is made of the low material of thermal conductivity.
The 5th, as the field coil of excitation unit.This field coil 5, by with boundling the wire harness of copper wire rod of surface insulation of 60 external diameter 0.2mm on the turning axle direction of heat generating roller 1, extend and along the circumferential disc of heat generating roller 1 around formation.In addition, the basal area of wire harness is about 7mm in the insulation sheath of wire rod is included in
2
The vertical section of turning axle with heat generating roller 1 of field coil 5 with week towards each other with the being close to configuration of wire harness along heat generating roller 1, makes its first half that covers heat generating roller 1, and makes it form overlapping 2 layers shape.In this case, constitute and make being close to each other from the wire harness of the end to end of heat generating roller 1 in abutting connection with wire harness, and being close to each other in abutting connection with wire harness making from the other end of heat generating roller 1 to the wire harness of this end.
In addition, extend the coiling order of the wire harness of coiling on the turning axle direction of heat generating roller 1, the order that begins from the center near coiling not necessarily also can be in middle part change order.
From half oscillatory type inverter is field circuit 6 applies alternating current from 30kHz to field coil 5.According to the temperature signal that the lip-deep temperature sensor 7 that is located at heat generating roller 1 records, the alternating current that puts on field coil 5 is controlled, so that reaching the fixing temperature of regulation, the surface of heat generating roller 1 is 170 ℃.Below, the alternating current that also will put on field coil 5 is called " coil current ".
In this example, the recording chart of A4 size (wide 210mm) is used as the recording chart of breadth extreme, and be 270mm with the axial length setting of the rotation of heat generating roller 1, with the axial length setting of the rotation along heat generating roller 1 of the peripheral part of field coil 5 is 230mm, is 200mm with the axial length setting of the rotation along heat generating roller 1 of the interior perimembranous of field coil 5.
With the surface upload toner 10 as the recording chart 8 that is recorded material, from the direction of arrow of Fig. 1 insert by as the fixing device of upper type formation, thus the toner on the recording chart 8 10 is carried out photographic fixing.
In this example, field coil 5 makes heat generating roller 1 heating by electromagnetic induction.Below, the limit describes its mechanism with reference to Fig. 3 limit.
The magnetic flux that the alternating current of origin self-excitation circuit 6 (Fig. 2) produces field coil 5 shown in the dotted line M among Fig. 3, because the magnetic of heat generating roller 1 and along the circumferential direction running through in the heat generating roller 1, and generates repeatedly and disappears.The induction current that is produced in heat generating roller 1 by the variation of this magnetic flux because of kelvin effect almost only flows through on the surface of heat generating roller 1, thereby produces Joule heat.
In this example, since with field coil 5 constitute make from the wire harness of the end to end of heat generating roller 1 be close to and make from the other end of heat generating roller 1 to the wire harness of this end each other in abutting connection with wire harness be close to each other in abutting connection with wire harness, so magnetic flux can not pass through between wire harness.In addition, shown in the dotted line M among Fig. 3, owing to do not have wire harness at the middle body of field coil 5 but the gap that magnetic flux is passed through is set, institute is so that magnetic flux forms the big loop that rotates around field coil 5.Further, owing to be relatively to be provided with heat generating roller 1 on the broad scope of about 180 degree of angle at center at turning axle with field coil 5, so can make magnetic flux along the circumferential direction connect the very broad scope of heat generating roller 1 with heat generating roller 1 along the circumferencial direction of heat generating roller 1.Therefore, owing to heat generating roller 1 generates heat on broad scope, so, also can drop into the power of regulation to heat generating roller 1 even coil current is little, the magnetic flux of generation is few.
As mentioned above, the magnetic flux owing to not do not connect heat generating roller 1 from passing through between the wire harness, institute does not pass to heat generating roller 1 so that put on the electromagnetic energy of field coil 5 with having leakage.Therefore, even coil current is little, also can drop into the power of regulation to heat generating roller 1.Further, be close to each other, can also make field coil 5 miniaturizations by making wire harness.
In addition, owing to make the close heat generating roller 1 in position of the wire harness of field coil 5, so can the magnetic flux that coil current produces be sent to heat generating roller 1 with high efficient.And, the flowing of the vortex flow that in heat generating roller 1, produces by this magnetic flux, the changes of magnetic field that can the bucking coil electric current causes.In this case, because the vortex flow that produces in coil current and the heat generating roller 1 is closer to each other,, thereby can suppress all electric currents magnetic field of space generation around so the effect of offsetting is bigger.
In addition since from the heat radiation of the periphery of field coil 5 without any obstruction, so can prevent the insulation sheath fusing that the temperature that causes because of accumulation of heat rises and makes wire rod, can prevent that maybe the resistance value of field coil 5 from increasing.
In Fig. 4, the field coil that makes under the field coil state relative with heat generating roller and the equivalent electrical circuit of heat generating roller are shown.In Fig. 4, r is the resistance of field coil 5 itself, and R is field coil 5 and a resistance when carrying out electromagnetic coupled relative with heat generating roller, and L is the total inductance of circuit.R can be by pulling down field coil 5 and try to achieve with the independent resistance that the LCR avometer is measured field coil 5 with the angular frequency of regulation from heat generating roller 1.R can be used as from making resistance under the relative state of field coil 5 and heat generating roller 1 deduct the value behind the r and tries to achieve.The independent inductance of L and field coil 5 does not have much difference.When in this circuit, flowing through electric current I, electric current I square with the product of resistance value as useful power consumption, thereby produce heat.The power that is consumed by r makes field coil 5 heatings, and the power that is consumed by R makes heat generating roller 1 heating.As to establish the power that heat generating roller 1 is dropped into be W, and then its mutual relationship is by 1 expression of following formula.
[formula 1]
W＝(R+r)×I
2
In addition, the voltage that is added on field coil 5 as facility is V, and then following formula 2 is set up.
[formula 2]
I＝V/{(R+r)
2+(ωL)
2}
From above (formula 2) as can be seen, when L and R are excessive, under certain voltage V, will can not get enough electric current I.Therefore, shown in above (formula 1), drop into power W deficiency, thereby can not get enough heats.On the contrary, when R is too small, does not consume useful power even flow through electric current I yet, thereby can not get enough heats yet.And when L was too small, will make half oscillatory type inverter was field circuit 6 cisco unity malfunctions.When the frequency that puts on the alternating current of field coil 5 from field circuit 6 was the scope of 25kHz～50kHz, R was that 0.5 Ω is above, 5 Ω are following, L is that 10 μ H are above, gets final product below the 50 μ H.In this case, the circuit component so not high by anti-electric current, proof voltage constitutes field circuit 6, can obtain enough input power and thermal value.In addition, in this scope,, also still can obtain same effect as the value of R and L even then the number of turns of field coil 5, field coil 5 change with the specification of the field coils such as interval 5 of heat generating roller 1.
In addition, in this example, as mentioned above, boundling 60 external diameter 0.2mm wire rod and constitute the wire harness of field coil 5.The structure of wire harness not necessarily is defined in this structure, preferably constitutes by the wire rod more than 50～200 external diameter 0.1mm of boundling, below the 0.3mm.If the external diameter of wire rod less than 0.1mm, then might break because of mechanical load.On the other hand, if the external diameter of wire rod surpasses 0.3mm, then the resistance (r among Fig. 4) to high-frequency ac current increases, thereby makes field coil 5 excessive heating.In addition, if the radical of the wire rod of formation wire harness less than 50, then increases because of basal area reduces to make resistance, thereby makes field coil 5 excessive heating.On the other hand, surpass 200,, and be difficult in the coiling number of turns that obtains stipulating in the space of regulation then because of the wire harness chap is difficult to field coil 5 to being coiled into arbitrary shape if constitute the radical of the wire rod of wire harness.The external diameter that causes wire harness greatly can satisfy above-mentioned condition below 5mm.According to said structure, can in narrow space, increase the number of turns of field coil 5, so not only can realize the miniaturization of field coil 5 but also can drop into necessary power to heat generating roller.
The wire harness of field coil 5 of coiling also can partly constitute separate each other certain interval but major part and be close to mutually, and this mode also is effective.In addition, the wire harness of the field coil 5 of coiling also can constitute and partly changes overlapping mode, makes the low part of height of field coil 5 can be with the littler electric current power bigger to the heat generating roller input.As the shape of field coil 5, as long as the width (length of circumferencial direction) that its coiling is arranged is greater than the height (stacked thickness) of field coil 5.
In addition, when the length on the turning axle direction of field coil 5 at heat generating roller 1 is grown than the length of heat generating roller 1, magnetic flux will connect the electroconductive member of the end of side plate 2 heat generating rollers such as grade 1.Therefore, the member of formation heating around making, thus reduced the transmission ratio of electromagnetic energy to heat generating roller 1.In this example, because the length of heat generating roller 1 is longer than the length of field coil 5 on the turning axle direction of heat generating roller 1, so almost all arrive heat generating roller 1 and can not arrive member of formation around side plate 2 grades by the magnetic flux of coil current generation.According to this configuration, the electromagnetic energy that puts on field coil 5 can be able to be delivered to heat generating roller 1 expeditiously.Particularly, when magnetic flux along the turning axle direction from heat generating roller 1 end face by the time, the vortex flow density of the end face of heat generating roller 1 is increased.In this case, generation is made the problem of the end face excessive heating of heat generating roller 1.
In this example, as mentioned above, according to the axial length of the rotation of heat generating roller 1 order from small to large, be followed successively by interior perimembranous, the recording chart of breadth extreme, the peripheral part of field coil 5, the heat generating roller 1 of field coil 5, field coil 5, on the part that recording chart 8 passes through, evenly coil along the turning axle direction and in the mode parallel with the turning axle direction of heat generating roller 1.Therefore, the heating of the heat generating roller 1 on the part that recording chart 8 passes through is distributed and become even.Consequently, the Temperature Distribution in the photographic fixing portion is become evenly, thereby can obtain stable photographic fixing effect.
[the 2nd example]
Fig. 5 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 2nd example, and Fig. 6 is the backplan that removes the heat generating part behind the heat generating roller of this fixing device of expression.In addition, the member identical with above-mentioned the 1st example to function is marked with identical symbol, and its explanation is omitted.
This example is with the difference of the 1st example, be not with wire harness overlapping be 2 layers but along the circumferential disc of heat generating roller 1 around, and a pair of back side iron core 9 is set at the back side of field coil 5.
As the material of back side iron core 9, adopt that relative permeability is 1000～3000, saturation magnetic flux density is that 200～300mT, specific insulation are the ferrite of 1～10 Ω m.In addition, as the material of back side iron core 9, except that ferrite, can also adopt the material of high permeabilities such as permalloy, high resistivity.
The section of back side iron core 9 forms the shape that the cylinder of external diameter 36mm, thick 5mm is cut off with the angles of about 90 degree vertically.Therefore, the basal area of back side iron core 9 is 243mm
2In addition, the basal area of field coil 5 is 7mm
2* 9 the circle * 2, be 126mm
2
Heat generating roller 1 forms the tubulose of external diameter 20mm, thick 0.3mm.Therefore, the basal area perpendicular to the face of turning axle of the inside of heat generating roller 1 is about 295mm
2So, comprise the basal area of the field coil 5 of back side iron core 9, greater than the basal area perpendicular to the face of turning axle of the inside of heat generating roller 1.In addition, the 5.5mm that is spaced apart of back side iron core 9 and heat generating roller 1.
In addition, in this example, the recording chart of A4 size (wide 210mm) is used as the recording chart of breadth extreme, and be 240mm with the axial length setting of the rotation of heat generating roller 1, with the axial length setting of the rotation along heat generating roller 1 of peripheral part of the field coil 5 of coiling is 200mm, with the axial length setting of the rotation along heat generating roller 1 of the interior perimembranous of field coil 5 is 170mm, and is 220mm with the axial length setting of the rotation along heat generating roller 1 of back side iron core 9.Bearing 3 (with reference to Fig. 2) as the supporting member of heat generating roller 1 is made of the steel as magnetic material.The 10mm that is spaced apart of this bearing 3 and back side iron core 9 is greater than the interval of back side iron core 9 with heat generating roller 1.
Other structures are identical with above-mentioned the 1st example.
Below, the effect of the fixing device that constitutes by mode as mentioned above is described.
By back side iron core 9 is set, can increase the inductance of field coil 5, thereby the electromagnetic coupled between field coil 5 and the heat generating roller 1 is improved, and can increase R in the equivalent electrical circuit of Fig. 4.Therefore, even also can drop into bigger power to heat generating roller 1 with identical coil current.Therefore, the field circuit 6 of the low cheapness of anti-electric current and proof voltage can be adopted, and the fixing device that heat time heating time is short can be realized.
In addition, shown in the dotted line M among Fig. 5, because the magnetic flux of the rear side of field coil 5 all passes through from the inside of back side iron core 9, so can prevent that magnetic flux from rearward leaking.Consequently, the heating that the electromagnetic induction because of the electroconductive member of periphery causes can be prevented, unnecessary irradiation of electromagnetic waves can be prevented simultaneously.
Further and since the coiling wire harness do not overlap each other, so that all wire harness of field coil 5 are all close with heat generating roller 1.Therefore, can the magnetic flux that coil current produces be sent to heat generating roller 1 with higher efficient.
In this example, field coil 5 and back side iron core 9 are arranged on the outside of heat generating roller 1 (heat generating part), heat up because of the Temperature Influence that is subjected to heat generating part so can prevent field coil 5 etc.Therefore, can make thermal value keep stable.Particularly, owing to adopted field coil 5 and the back side iron core 9 perpendicular to the basal area of the face of turning axle of basal area, so heat generating roller 1 that can thermal capacity is little, the field coil 5 that the number of turns is many, an amount of ferrite (back side iron core 9) are used in combination greater than the inside of heat generating roller 1.Therefore, can be when suppressing the thermal capacity of fixing device with the coil current of regulation to the bigger power of generating component input.
In this example, as mentioned above,, be followed successively by interior perimembranous, the peripheral part of field coil 5, the recording chart of breadth extreme, back side iron core 9, the heat generating roller 1 of field coil 5 according to the axial length of the rotation of heat generating roller 1 order from small to large.And in this manner, the axial length of the rotation along heat generating roller 1 of peripheral part that makes field coil 5 is less than the width of the recording chart of breadth extreme, on the other hand, make the width of the axial length of the rotation along heat generating roller 1 of back side iron core 9 greater than the recording chart of breadth extreme, so, even the coiling of field coil 5 exists to a certain degree inhomogeneous, also can make from the magnetic field that field coil 5 arrives heat generating rollers 1 and become even in the turning axle direction.Therefore, the heating of the heat generating roller 1 on the part that recording chart passes through is distributed and become even.Thus, the Temperature Distribution in the photographic fixing portion is become evenly, thereby can obtain stable photographic fixing effect.In addition, reduce the axial length of rotation of heat generating roller 1 and the axial length of the rotation along heat generating roller 1 of field coil 5 uniformly simultaneously, so miniaturization that can implement device and reducing cost owing to can also distribute to become in the heating that makes heat generating roller 1.Further, because the axial length of the rotation along heat generating roller 1 of back side iron core 9 is shorter than the axial length of the rotation of heat generating roller 1, make the end face excessive heating of heat generating roller 1 so can prevent the vortex flow density of the end face of heat generating roller 1 from uprising.
In addition, as mentioned above, as the bearing 3 (with reference to Fig. 2) of the supporting member of heat generating roller 1, the general steel with magnetic that adopts is to guarantee physical strength.So the magnetic flux that is produced by coil current is easy to be attracted by bearing 3, when connecting bearing 3, magnetic flux will produce.Therefore, reduced the transmission ratio of electromagnetic energy to heat generating roller 1.Make the temperature rising of bearing 3 simultaneously and shortened life span.In this example, as mentioned above,, be set at greater than the interval of back side iron core 9 with heat generating roller 1 with the interval of bearing 3 with back side iron core 9, so the magnetic flux of perforation back side iron core 9 can not be directed to bearing 3, thereby make its most of heat generating roller 1 that connects.Therefore, the electromagnetic energy of supplying with field coil 5 heat generating roller 1 can be delivered to expeditiously, the heating of bearing 3 can be prevented simultaneously.
The interval (being 10mm in this example) of bearing 3 and back side iron core 9 gets final product greater than the interval (being 5.5mm in this example) of back side iron core 9 with heat generating roller 1, is preferably in more than 2 times.
In addition, because the thickness of back side iron core 9 is even, so the inside of iron core 9 can not store heat in the part overleaf.Further since from the heat radiation of the periphery of back side iron core 9 without any obstruction, lower so can prevent the temperature that causes because of the accumulation of heat saturation magnetic flux density that makes back side iron core 9 that rises, thereby can prevent the rapid reduction of magnetoconductivity as a whole.Therefore, can for a long time heat generating roller 1 stably be remained on the temperature of regulation.
[the 3rd example]
Fig. 7 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 3rd example, and in addition, the member identical with above-mentioned the 2nd example to function is marked with identical symbol, and its explanation is omitted.
This example is with the difference of above-mentioned the 2nd example, as shown in Figure 7, back side iron core 9 is extended to the scope that does not have field coil 5, and obstructed overexcitation coil 5 is set and " opposed the F " relative with heat generating roller 1.Below, with in the back side iron core 9 pass through field coil 5 and the part relative with heat generating roller 1 is called " T of magnetic conduction portion ".In addition, the section of back side iron core 9 forms the shape that cylinder is cut off with the angle of about 180 degree vertically.
In this case, can constitute magnetic circuit by more ferrite (back side iron core 9).Therefore, the low air part of magnetoconductivity that the magnetic flux that is produced by coil current passes through, just the close gap part between heat generating roller 1 and the back side iron core 9.So, the inductance of field coil 5 is increased, and the heat generating roller 1 that can almost all lead by the magnetic flux that coil current produces.Consequently, the electromagnetic coupled between heat generating roller 1 and the field coil 5 is further improved, and the R in the equivalent electrical circuit of Fig. 4 is further increased.According to this configuration, though with identical coil current also can be bigger to the generating component input power.
In addition, shown in the dotted line M among Fig. 7, from the magnetic flux of back side iron core 9 guiding heat generating rollers 1, by opposed F.Along the length of axial opposed the F of the rotation of heat generating roller 1, with the axial equal in length of the rotation along heat generating roller 1 of back side iron core 9, thereby longer than the width of recording chart.Therefore, can make magnetic flux incide the part that recording chart passes through equably from opposed F.So, can evenly heat the required scope of the photographic fixing of heat generating roller 1.
In addition, in this example, the side relative that field coil 5 is configured in back side iron core 9 with heat generating roller 1, but as shown in Figure 8, also can wire harness be extended axially winding in iron core 9 upper edges, the back side of semicircle tubular on one side, the circumferencial direction coiling of one edge heat generating roller 1, thus constitute field coil 5.In this case,, not only connect the side by field coil 5 of the circumference of heat generating roller 1, and connect a side (the dotted line M ' among the figure) by backer roll by the magnetic flux that coil current produces.Consequently, make the whole circumference heating of heat generating roller 1, so even overall thermal value is increased with identical coil current.In addition, because the basal area that magnetic flux passed through increase, so even have more magnetic flux to connect the saturation magnetic flux density that heat generating roller 1 also can not surpass heat generating roller 1.Therefore, can prevent that magnetic flux from passing through heat generating roller 1 space in addition, so can heat 1 pair of heat generating roller by electromagnetic induction with higher efficient.
[the 4th example]
Fig. 9 is that expression will be used as the sectional drawing of the image processing system of fixing device as the image heating of the present invention's the 4th example, Figure 10 A is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 4th example, the perspective view of Figure 11 heat generating part that to be expression look from the direction of the arrow G of Figure 10 A, Figure 12 are the sectional drawings of heat generating part of face that is comprising the center of the turning axle of heat generating roller and field coil.
In Fig. 9, the 11st, Electrophtography photosensor (below, claim " photosensitive drums ").Photosensitive drums 11, one side is driven rotation with predetermined circumference speed along the direction of arrow, and one side makes its surface by negative dark potential V0 uniform charged by charger 12.The 13rd, laser beam scanner, output is according to the laser beam 14 of the electric digital pixel signal modulation of the time series of the picture information of importing from main device such as not shown image reading apparatus or computing machine.The surface of the photosensitive drums 11 after charged is by these laser beam 14 scan exposures.Thus, make the current potential absolute value of the exposed portion of photosensitive drums 11 reduce and become bright current potential VL, thus the formation electrostatic latent image.This sub-image is developed by the electronegative toner of developer 15, becomes visible image.
On the other hand, supply with recording chart 8 one by one from sheet feed section 17, and with its with and the accurate sequential of the rotational synchronization of photosensitive drums 11 be transported to roll gap portion between photosensitive drums 11 and the transfer roll 19 by a pair of contraposition roller 18.Then, by the transfer roll 19 that has applied transfer bias the toner picture on the photosensitive drums 11 is transferred on the recording chart 8 successively.Make the photosensitive drums 11 after recording chart 8 separates, after by cleaning device 20 residues such as the residual toner of its lip-deep transfer printing being removed, use for image formation next time repeatedly.
The 21st, the photographic fixing lateral paper guide is led to the mobile of fixing device 22 by the recording chart 8 after 21 pairs of transfer printings of this photographic fixing lateral paper guide.Recording chart 8 after photosensitive drums 11 separation, is transported to fixing device 22, thereby looks like to carry out photographic fixing by the toner of 22 pairs of transfer printings of fixing device on recording chart 8.The 23rd, row's paper guide plate will be by the 8 guide piece outsides of the recording chart behind the fixing device 22 by this row's paper guide plate 23.Above-mentioned photographic fixing lateral paper guide 21, row's paper guide plate 23 are made of resins such as ABS.In addition, photographic fixing lateral paper guide 21, row's paper guide plate 23 also can be made of nonmetallic materials such as aluminium.The recording chart 8 of toner picture after by photographic fixing is discharged on the discharge tray 24.
The 25th, the base plate of device body, the 26th, the top board of device body, the 27th, the body casing, these members constitute the intensity that one is guaranteeing to install body.These members are matrix material with the steel as magnetic material, and are made of the material after zinc-plated.
The 28th, cooling fan, this cooling fan 28 makes and produces air-flow in the device.The 29th, by the coils overwraps as shading member that nonmagnetic materials such as aluminium constitute, this coils overwraps 29 constitutes the back side iron core 9 (with reference to Figure 10 A) that makes its covering field coil 5.
Below, the fixing device as the image heating of this example is elaborated.
In Figure 10 A, the photographic fixing band 31 of thin thickness is the diameter 50mm that is made of polyamide of matrix material, the annular jointless band of thick 100 μ m.On the surface of photographic fixing band 31, be covered with the release layer (not shown) of the thick 20 μ m that constitute by fluorine resin, so that it has release property.As matrix material, except that having stable on heating polyamide and fluorine resin etc., can also use the metals made from electrocasting as thin as a wafer such as nickel.As release layer, also can be used alone or as a mixture PTFE, PFA, FEP, silicon rubber, contain good resin or the rubber of release property such as fluororubber.When photographic fixing band 31 is used for the photographic fixing of monochrome image, only guarantee that release property gets final product, but, then preferably make it have elasticity as photographic fixing band 31 being used for the photographic fixing of color image, in this case, must further form thick rubber layer.
As the field coil 5 of excitation unit, by with boundling the wire harness of copper wire rod of surface insulation of 60 external diameter 0.2mm on the turning axle direction of heat generating roller 1, extend and along the circumferential disc of heat generating roller 1 around formation.The basal area of wire harness is about 7mm in the insulation sheath of wire rod is included in
2
As 10A～shown in Figure 12, field coil 5 forms and covers the section configuration that installs around the photographic fixing band 31 on heat generating roller 1.In this case, the excitation width of field coil 5 on the moving direction of photographic fixing band 31 is less than the contact range (install around scope) of photographic fixing band 31 with heat generating roller 1.When the part adstante febre of not captured heat of heat generating roller 1 by photographic fixing band 31, the problem that exists above the heat resisting temperature of the material of photographic fixing band 31 and be easy to make the temperature of heat generating roller 1 to rise.But, according to the structure of this example, owing to only make the scope that contact with photographic fixing band 31 heating on the heat generating roller 1, so the temperature anomaly rising of the rod 1 that can prevent to generate heat.In addition, wire harness is only overlapping in two ends (axial two ends of the rotation of heat generating roller 1) of field coil 5, and circumferentially enclosing with the state coiling 9 that is close to mutually along heat generating roller 1.Swell under the state that makes overlapping 2 rows of wire harness two ends of field coil 5 on the turning axle direction of heat generating roller 1.That is, field coil 5 forms the shape of similar saddle as a whole.Therefore, can evenly heat the axial wideer scope of the rotation of heat generating roller 1.In addition, the distance increase owing to wire harness overlapping in two ends of field coil 5 and heat generating roller 1 does not cause local temperature too high so can not make vortex flow concentrate on this part.
Back side iron core 9 is made of C shape iron core 32 and central core 33.C shape iron core 32, width are 10mm, along be separated by 7 of the arranged spaced of 25mm of the turning axle direction of heat generating roller 1.According to this configuration, can capture leakage magnetic flux to the outside.Central core 33 then is positioned at the middle position of field coil 5 coilings, and the shape of constituent ratio C shape iron core 32 protrusions.That is, central core 33, constitute among opposed the F of iron core 9 overleaf one to heat generating roller 1 near the N of portion (with reference to Figure 13).In addition, the basal area of central core 33 is 3mm * 10mm.
In addition, central core 33 for ease of ferritic processing, structurally also can be divided into several along the turning axle direction of heat generating roller 1.In addition, central core 33 also can constitute the shape that is combined into one with C shape iron core 32.Further, also can constitute the shape that is combined into one with C shape iron core 32 and be divided into several along the turning axle direction of heat generating roller 1.
The 34th, the heat insulating component of the thick 1mm that constitutes by high resins of heat resisting temperature such as PEEK material or PPS.In the end of heat insulating component 34, be provided with the two ends maintaining part 34a of the bump that is used to keep two ends of field coil 5 on the turning axle direction of heat generating roller 1.According to this configuration, can prevent that the two ends bump of field coil 5 is defeated and dispersed, can limit the position in the outside of field coil 5 simultaneously.
The material of back side iron core 9 is identical with above-mentioned the 2nd example.Except that central core 33, comprising the section configuration of the back side iron core 9 on the section of C shape iron core 32 and the shape of heat generating roller 1, also all identical with above-mentioned the 2nd example.Therefore, on the basal area of the field coil 5 that comprises back side iron core 9 basal area this point, also identical with above-mentioned the 2nd example perpendicular to the face of turning axle greater than the inside of heat generating roller 1.
Put on the alternating current of field coil 5 from field circuit 6 (with reference to Fig. 2), identical with above-mentioned the 1st example.According to the temperature signal that records by the lip-deep temperature sensor that is located at photographic fixing band 31, the alternating current that puts on field coil 5 is controlled, make the temperature of photographic fixing band 31 reach promptly 190 ℃ of the fixing temperatures of regulation.
Shown in Figure 10 A, photographic fixing band 31, being suspended on by the surface with the tension force of regulation is on the heat generating roller 1 of the fixing roller 35 of low heat conductivity of the diameter 20mm that constitutes as the silicon rubber of rubber-like foams of soft (JISA30 degree) and diameter 20mm, and can rotate mobile in the direction of arrow B.Here, at the two ends of heat generating roller 1, be provided with the costal margin (not shown) of the teeter that is used to prevent photographic fixing band 31.In addition, the backer roll 4 as pressue device is crimped on the fixing roller 35 across photographic fixing band 31, and forms roll gap portion therefrom.
In this example, the recording chart of A4 cun (wide 210mm) is used as the recording chart of breadth extreme, and be 230mm with the width setup of photographic fixing band 31, with the axial length setting of the rotation of heat generating roller 1 is 260mm, with back side iron core 9 length setting between the end of the outermost end on the turning axle direction of heat generating roller 1 is 225mm, with the axial length setting of the rotation along heat generating roller 1 of peripheral part of the field coil 5 of coiling is 245mm, is 250mm with the axial length setting of the rotation along heat generating roller 1 of heat insulating component 34.
In this example, field coil 5, back side iron core 9 and heat generating roller 1 constitute by aforesaid mode, and field coil 5 makes heat generating roller 1 heating by electromagnetic induction.Below, the limit describes its mechanism with reference to Figure 13 limit.
As shown in figure 13, the magnetic flux that is produced by coil current enters heat generating roller 1 from opposed F of back side iron core 9.In this case, shown in the dotted line M among the figure, the magnetic flux by coil current produces along the circumferential direction runs through in the heat generating roller 1 owing to the magnetic of heat generating roller 1.And, this magnetic flux from back side iron core 9 to heat generating roller 1 be that central core 33 forms big loop via the T of magnetic conduction portion near the N of portion, and generate repeatedly and disappear.Induction current by the variation of this magnetic flux produces produces Joule heat, and is identical with above-mentioned example 1 in this.
In this example, as shown in figure 11, the C shape iron core 32 that width is narrow is a plurality of along the turning axle direction of the heat generating roller 1 impartial arranged spaced of being separated by, if be this structure, then the magnetic flux that along the circumferential direction flows through at the back side of field coil 5 will concentrate on the part of C shape iron core 32, flow through the air between the C shape iron core 32 of adjacency hardly.Therefore, the magnetic flux that enters heat generating roller 1 has the tendency that concentrates on the part that C shape iron core 32 exists.So, the part relative with C shape iron core 32 that makes heat generating roller 1 is easier to heating, but, in this example, form central core 33 at the middle position of field coil 5 coiling, on the turning axle direction of heat generating roller 1, be provided with continuously, so enter the magnetic flux of heat generating roller 1 from opposed F of C shape iron core 32 near the N of portion, in heat generating roller 1, also flow, thereby make being evenly distributed along the turning axle direction.Therefore, can make the unevenness of the thermal value of heat generating roller 1 obtain relaxing.
From the lead effect of other opposed F of opposed F of C shape iron core 32, distributing with incident to the magnetic flux of heat generating roller 1 does not have direct relation with the magnetic flux of the T of magnetic conduction portion.Therefore, with the T of magnetic conduction portion and opposed the mode that F constitutes respectively, be very effective to the optimization of the shape of back side iron core 9.The T of magnetic conduction portion only need make opposed F axially evenly get final product axially not necessarily requiring evenly as far as possible.
Since by make central core 33 for the shape of protruding than C shape iron core 32 be provided with to heat generating roller 1 near the N of portion, so can constitute magnetic circuit by more ferrite.Therefore, the low air part of magnetoconductivity that the magnetic flux that produced by coil current is passed through, just the close gap part between heat generating roller 1 and the back side iron core 9.So, the inductance of field coil 5 is further increased, and the heat generating roller 1 that can lead more by the magnetic flux that coil current produces, therefore the electromagnetic coupled between heat generating roller 1 and the field coil 5 is improved.According to this configuration, though with identical coil current also can be bigger to the generating component input power.Particularly, because the magnetic flux that is produced by coil current must pass through from the middle body of field coil 5 coilings, so by this part setting by turning axle direction at heat generating roller 1 on continuous central core 33 constitute near the N of portion, heat generating roller 1 expeditiously can be led by the magnetic flux that coil current produces.
The basal area at the circumferencial direction of the T of magnetic conduction portion of C shape iron core 32 is set at the peakflux density that the density that makes the magnetic flux of deriving from field coil 5 is no more than the material that is adopted.This magnetic flux density is set at about 80% of ferritic saturation magnetic flux density when maximum.Magnetic flux density during this maximum needs only below 100% the ratio of saturation magnetic flux density, but preferably is set at from 50% to 85% scope in practicality.Too high as this ratio, the magnetic flux density when then maximum surpasses saturation magnetic flux density because of the deviation of environment or member sometimes.In this case, magnetic flux will flow to the back side of back side iron core 9, thereby the member of back is heated.On the contrary, low excessively as this ratio, then need use ferrite, so the cost of device will be improved above the high price of necessary amount.
In addition, C shape iron core 32, a plurality of with uniform width along the turning axle direction of the heat generating roller 1 bigger arranged spaced of being separated by, so can not make back side iron core 9 and field coil 5 store heat.Further, since from the heat radiation of the periphery of back side iron core 9 and field coil 5 without any obstruction, so can prevent the temperature rising that causes because of accumulation of heat the ferritic saturation magnetic flux density of back side iron core 9 is lowered, thereby can prevent the rapid reduction of magnetoconductivity as a whole.In addition, can also prevent the insulation sheath fusing of wire rod and make between the wire rod and be short-circuited.Therefore, can for a long time heat generating roller 1 stably be remained on the temperature of regulation.
In addition, overlapping owing to forming with two ends of wire harness on the turning axle direction of the heat generating roller 1 of field coil 5, so can make the turning axle direction uniformly extension of field coil 5 at wideer scope upper edge heat generating roller 1.On the contrary, owing to can when guaranteeing uniform heating region, reduce the width of two ends on the turning axle direction of heat generating roller 1 of field coil 5, so miniaturization that can implement device integral body.
In addition, in this example,, be followed successively by recording chart, back side iron core 9, photographic fixing band 31, the peripheral part of field coil 5, heat insulating component 34, the heat generating roller 1 of breadth extreme according to the axial length of the rotation of heat generating roller 1 order from small to large.That is, the length of heat insulating component 34 is longer than the length of field coil 5 and back side iron core 9.And, because back side iron core 9 is relative with heat generating roller 1 and photographic fixing band 31 across heat insulating component 34, so even back side iron core 9 during near heat generating roller 1, also can be prevented the temperature rising of back side iron core 9.In addition, can also prevent that cooling draught from contacting with photographic fixing band 31 and with 31 coolings of photographic fixing band.
In addition, because the width of photographic fixing band 31 is longer than the axial length of the rotation along heat generating roller 1 of back side iron core 9,, so can prevent the excessive temperature rising of the heat generating roller 1 of this part so the heat generating roller 1 of the part that can contact with photographic fixing band 31 does not heat.
In addition, by coils overwraps 29 is set, can prevent that a spot of frequency electromagnetic waves that produces to the back side of back side iron core 9 leaked magnetic flux with from field coil 5 from propagating in that device is inside and outside.Consequently, can prevent that the inside and outside circuit of locking apparatus because of electromagnetic noise misoperation takes place.
Further, owing to the space that will be surrounded by coils overwraps 29 and heat insulating component 34 makes air flow from cooling fan as ventiduct, so heat generating roller 1 and photographic fixing band 31 are cooled off, and just field coil 5 and back side iron core 9 are cooled off.
In addition, the magnetic component of constituent apparatus such as the base plate 25 of device body, top board 26, body casing 27 is set 20mm with the nearest interval of field coil 5.According to this configuration, the magnetic flux that can prevent the inside by back side iron core 9 is radiated the outside of field coil 5 from the position beyond opposed the F and incides magnetic member such as body casing 27, consequently, can not carry out unnecessary heating, and the electromagnetic energy of supplying with field coil 5 can be put into heat generating roller 1 expeditiously the member of formation of device.Though the minimum value at the interval of magnetic members such as field coil 5 and body casing 27 is set 20mm, but more than 1.5 times of interval also preferably are somebody's turn to do greater than the back side iron core 9 and the interval of heat generating roller 1 in the interval as magnetic members such as back side iron core 9 and body casings 27, can prevent that then magnetic flux is to the leakage of the back side of field coil 5.In this example, owing to must constitute by resin, so can be easy to guarantee enough intervals between iron core 9 and other magnetic components overleaf with the close photographic fixing lateral paper guide 21 of fixing device 22, row's paper guide plate 23.
In addition, in this example, heat generating roller 1 (heat generating part) is arranged on the inboard of photographic fixing band 31, and field coil 5 and back side iron core 9 are arranged on the outside of photographic fixing band 31, so, can prevent that field coil 5 grades are subjected to the temperature effect of heat generating part and heat up.Therefore, can make thermal value keep stable.Particularly, owing to adopted field coil 5 and the back side iron core 9 perpendicular to the basal area of the face of turning axle of its basal area, so heat generating roller 1 that can thermal capacity is little, the field coil 5 that the number of turns is many, an amount of ferrite (back side iron core 9) are used in combination greater than the inside of heat generating roller 1.Therefore, can be when suppressing the thermal capacity of fixing device 22 with the coil current of regulation to the bigger power of generating component input.Consequently, the field circuit 6 (with reference to Fig. 2) of the low cheapness of anti-electric current and proof voltage can be adopted, and the fixing device 22 that heat time heating time is short can be realized.In this example,, can drop into the power of 800W to heat generating roller 1 with effective value voltage 140V (voltage amplitude 500V), effective value electric current 22A (peak point current 55A) from the alternating current of field circuit 6.
Heat generating roller 1 passed through the temperature sensor (not shown) is being set near the position with the contact site of photographic fixing band 31.Be controlled at steady state value by the temperature with this part, the temperature of the photographic fixing band 31 in the time of can be with the roll gap portion that enters fixing roller 35 and backer roll 4 remains at steady state value.Consequently, even when many continuous recording charts 8 are carried out photographic fixing, also can stably carry out this photographic fixing.
In addition, field coil 5 and back side iron core 9 are covered with almost half of circumference of heat generating roller 1, so can make the whole zone heating of photographic fixing band 31 and the contact site of heat generating roller 1.Therefore, can will send photographic fixing band 31 more to from the heat energy of field coil 5 by the electromagnetic induction transmission.
In addition, in this example, the material of heat generating roller 1 and photographic fixing band 31, thickness etc. can be distinguished independent setting.Therefore, as material, the thickness of heat generating roller 1, can select to be best suited for material, the thickness of the electromagnetic induction heating of carrying out field coil 5.And, can select to be best suited for the material, the thickness that carry out photographic fixing as material, the thickness of photographic fixing band 31.
In this example, for reaching the purpose that shortens heat time heating time, set the thermal capacity of photographic fixing band 31 as far as possible little, simultaneously thickness by reducing heat generating roller 1 and external diameter and its thermal capacity is set at very little value.Therefore, under the input power of 800W, begin in about 15 seconds, can reach the temperature of regulation from the intensification that is used for photographic fixing.
In addition, in this example, along the turning axle direction of the heat generating roller 1 impartial arranged spaced of being separated by, but it at interval also not necessarily must be impartial with C shape iron core 32.Can adjust the interval according to heat dissipating state and contact members such as having or not temperature sensor, thereby design heating freely distributes so that Temperature Distribution becomes even.
In addition, in this example, back side iron core 9 comprises along the turning axle direction of heat generating roller 1 the be separated by uniform a plurality of C shape iron cores 32 of the thickness that is made of ferrite of impartial arranged spaced and the central core 33 that is made of ferrite equally, but not necessarily is defined in this structure.For example, also can be the structure that on the whole back side iron core 9 continuous, is provided with a plurality of holes along the turning axle direction of heat generating roller 1.In addition, also can be that a plurality of parts that will be made of ferrite are distinguished the structure that distributes independently at the back side of field coil 5.
In addition, in this example, the matrix material of photographic fixing band 31 is made of resin, but also can constitute with ferromagnetism metals such as nickel without resin.In this case, the part of the heating that electromagnetic induction causes will take place in photographic fixing band 31, thereby photographic fixing band 31 itself is heated, so electromagnetic energy more effectively can be passed to photographic fixing band 31.
In addition, in this example, the base plate 25 of device body, the top board 26 of device body, body casing 27 are made of magnetic material, but also can constitute with resin material without magnetic material.In this case, the member of intensity that is guaranteeing to install body to the magnetic line of force without any influence, so can be with these members near 9 configurations of back side iron core.Consequently, overall miniaturization that can implement device.
In addition, in this example, the two ends that structurally make heat generating roller 1 are by bearing 3 supportings, but as shown in figure 14, also can be by the flange 36 that is made of the little heat stable resin of heat conductivities such as phenolics at the two ends that are located at heat generating roller 1 and central shaft 37 supportings that connect two flanges 36.As adopt this structure, then can suppress heat or magnetic flux and leak from the two ends of heat generating roller 1.
In addition, in this example,, be set at less than the contact range (install around scope) of photographic fixing band 31, but not necessarily be defined in this structure with heat generating roller 1 with the excitation width of field coil 5 on the moving direction of photographic fixing band 31.For example, shown in Figure 10 B, also the excitation width of the field coil on the moving direction of photographic fixing band 31 5 (can be installed around scope: boundary line b) prolong to fixing roller 35 sides from the contact range of photographic fixing band 31 and heat generating roller 1.According to this configuration, compare with the structure of Figure 10 A, can make the heating of heat generating roller 1 reach wideer scope (scope among Figure 10 B a), so, even also can obtain enough thermal values with little coil current.In addition, in this case, after wire harness coiling and forming field coil 5,, make the section of the wire harness of coiling be roughly square, and make between the wire harness and further be close to each other by with field coil 5 compressions.According to this configuration, can reduce the possessive volume of field coil 5, so can make the more number of turns of field coil 5 coilings.Consequently, the current density of coil current is increased,, thereby thermal value is increased so the density of the vortex flow of generation also increases in heat generating roller 1.Therefore, can reduce needed coil current or reduce the diameter of heat generating roller 1.Further, owing to can strengthen the interval of back side iron core 9 and field coil 5, thus help the heat radiation of back side iron core 9, thereby can prevent that the temperature of back side iron core 9 from rising.In addition, owing to make wire harness lean on tightlyer mutually, institute is so that the bonding between wire harness is more firm, thereby can make the shape of field coil 5 maintenance monomer whoses.Therefore, the assembling procedure of fixing device 22 has been become simply.
[the 5th example]
Figure 15 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 5th example, and in addition, the member identical with above-mentioned the 4th example to function is marked with identical symbol, and its explanation is omitted.
As shown in figure 15, different with above-mentioned the 4th example in this example, the position relative with heat generating roller 1 of opposed F of back side iron core 9 formed more convex near heat generating roller 1.
Other structures are identical with above-mentioned the 4th example.
According to this example, magnetic circuit can be made of basically fully ferrite.Therefore, by the low air part of the magnetoconductivity that magnetic flux passed through that coil current produces, be the close gap part between heat generating roller 1 and the back side iron core 9.Therefore, the inductance of field coil 5 is further increased, and the heat generating roller 1 that can almost all lead by the magnetic flux that coil current produces.Consequently, the electromagnetic coupled between heat generating roller 1 and the field coil 5 is improved, and the R in the equivalent electrical circuit of Fig. 4 is increased.Therefore, though with identical coil current also can be bigger to the generating component input power.In this example, heat generating roller 1 is dropped into the power of 800W with effective value electric current 20A (peak point current 50A).
In addition, because back side iron core 9 is relative with heat generating roller 1 and photographic fixing band 31 across heat insulating component 34, so even back side iron core 9 during near heat generating roller 1, also can be prevented the temperature rising of back side iron core 9.
[the 6th example]
Figure 16 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 6th example, and Figure 17 is the perspective view of the heat generating part of looking from the direction of the arrow A of Figure 16.In addition, the member identical with above-mentioned the 5th example to function is marked with identical symbol, and its explanation is omitted.
As Figure 16, shown in Figure 17, different with above-mentioned the 5th example in this example, opposed F as back side iron core 9 is being provided with opposed iron core 38 continuous on the turning axle direction of heat generating roller 1.In addition, the recording chart of A4 size (wide 210mm) is used as the recording chart of breadth extreme, and be 240mm with the axial length setting of the rotation of heat generating roller 1, with C shape iron core 32 length setting between the end of the outermost end on the turning axle direction of heat generating roller 1 beyond the opposed iron core 38 is 200mm, with the axial length setting of the rotation along heat generating roller 1 of the interior perimembranous of field coil 5 is 210mm, is 220mm with the axial length setting of the rotation along heat generating roller 1 of opposed iron core 38.
Other structures are identical with above-mentioned the 5th example.
In this example, make the width of the axial length of the rotation along heat generating roller 1 (the axial length of the rotation along heat generating roller 1 of the interior perimembranous of field coil 5) of the T of magnetic conduction portion of field coil 5 less than the recording chart of breadth extreme, on the other hand, make the width of the axial length of the rotation along heat generating roller 1 (the axial length of the rotation along heat generating roller 1 of opposed iron core 38) of opposed F of back side iron core 9 greater than the recording chart of breadth extreme, so, even on the back side iron core 9 of the T of magnetic conduction portion, gap and skewness are set, also can make from the magnetic field of opposed F arrival heat generating roller 1 and become even in the turning axle direction.According to this configuration, the heating of recording chart by the heat generating roller on the part 1 distributed become evenly, so that the temperature in the photographic fixing portion becomes even.Therefore, can obtain stable photographic fixing effect.In addition, can also distribute to become in the heating that makes heat generating roller 1 and reduce the back side iron core 9 of the T of magnetic conduction portion uniformly simultaneously, so the miniaturization of energy implement device makes cost reduce simultaneously.
In addition, in this example, make opposed iron core 38 setting continuously on the turning axle direction of heat generating roller 1, but also not necessarily be defined in this structure as opposed F of back side iron core 9.For example, as shown in figure 18, also can constitute and make the width of opposed F on the turning axle direction of heat generating roller 1 than the wide shape of the T of magnetic conduction portion with opposed iron core 38 disjunctions and with back side iron core 9.According to this configuration, because back side iron core 9 minimizings of opposed F, so can alleviate the weight of back side iron core 9.In addition, owing to can increase the surface area of opposed the F that temperature is easy to raise, can promote to cool off by heat radiation.
[the 7th example]
Figure 19 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 7th example, and Figure 20 is the perspective view of the heat generating part of looking from the direction of the arrow A of Figure 19.In addition, the member identical with above-mentioned the 5th example to function is marked with identical symbol, and its explanation is omitted.
As Figure 19, shown in Figure 20, in this example, different with above-mentioned the 5th example, C shape iron core 38 is formed covering is approximately the scope of 90 degree with respect to the turning axle direction of heat generating roller 1 shape, change C shape iron core 38a, 38b that the orientation is set, configuration alternately on the turning axle direction of heat generating roller 1.That is, opposed F of back side iron core 9, the center line that is configured to respect to the axial field coil 5 of the rotation of heat generating roller 1 is asymmetrical position.
In above-mentioned the 5th example, the same circumferential section that makes heat generating roller 1 is with respect to opposed the F at 2 positions of C shape iron core 32 and rotate, so heat generating roller 1 and relative part C shape iron core 32 differ greatly with the thermal value of part beyond it, thereby are easy to make Temperature Distribution to produce very big inequality.And in this example, the same circumferential section of heat generating roller 1 rotates with respect to opposed the F at a position of C shape iron core 38, so heat generating roller 1 and relative part C shape iron core 38 can not produce very large deviation with the thermal value of part beyond it.In addition, can also reduce the volume of employed back side iron core 9, in the time of can shortening simultaneously heat generating roller 1 and rotate at opposed F relative partly the track spacing of the lip-deep of heat generating roller 1 with back side iron core 9.Promptly, if the same axial length setting of the rotation along heat generating roller 1 with opposed F with above-mentioned the 6th example is 220mm, then be arranged side by side 5 C shape iron cores 38 listing one, its spacing is 44mm, because dispose 2 row C shape iron core 38a, 38b alternately, so, when heat generating roller 1 rotates, with the staggered relative spacing partly of opposed F, only be the 22mm of half in getting on outwardly of heat generating roller 1.Therefore, in this example, heat generating roller 1 and relative part C shape iron core 38 can not produce very large deviation with the thermal value of part beyond it, and, because the interval of opposed the F that heating is concentrated reduces,, heating becomes even so being distributed.The temperature inequality that consequently, can suppress heat generating roller 1 and photographic fixing band.
In addition, because back side iron core 9 minimizings of opposed F, so can alleviate the weight of back side iron core 9.Further, owing to can increase the surface area of opposed the F that temperature is easy to raise, can promote to cool off by heat radiation.Therefore, the inside of iron core 9 can not store heat in the part overleaf.According to this configuration, the saturation magnetic flux density attenuating that the temperature that causes because of accumulation of heat rises and makes back side iron core 9 can be prevented, thereby the rapid reduction of magnetoconductivity as a whole can be prevented.Consequently, can for a long time heat generating roller 1 stably be remained on the temperature of regulation.
[the 8th example]
Figure 21 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 8th example, and Figure 22 is the perspective view of the heat generating part of looking from the direction of the arrow A of Figure 21.In addition, the member identical with above-mentioned the 4th example to function is marked with identical symbol, and its explanation is omitted.
As Figure 19, shown in Figure 20, this example structurally makes the interval of the C shape iron core 32 of adjacency change along the turning axle direction of heat generating roller 1, and is different with above-mentioned the 4th example in this.In Figure 22, d1=21mm, d2=21mm, d3=18mm.Therefore, constitute the relation of d1=d2＞d3.In other words, the interval of the back side iron core 9 of adjacency is narrowed down.In addition, also the square parts 40 that are made of ferrite of 5mm are being set with being provided with to contact with the surface of photographic fixing band and be used to measure on the identical position, the position of temperature sensor 7 of temperature.
, when the interval of the back side iron core 9 that makes adjacency was impartial, the end region temperature of heat generating roller 1 and photographic fixing band reduced sometimes.And the axial temperature inequality of the rotation of this heat generating roller 1 will cause photographic fixing bad.
In this example, as mentioned above, make the interval of back side iron core 9 of adjacency narrower in the end of heat generating roller 1, so the magnetic flux by coil current produces correspondingly increases than central portion in the end of heat generating roller 1 than the interval of its central portion.Therefore, the end-heating amount at heat generating roller 1 increases.But on the other hand,, because to the heat conduction of bearing etc., be easy to be captured more heat so compare with central portion in the end of heat generating roller 1.Therefore, the effect of this two aspect is cancelled out each other, and the Temperature Distribution of heat generating roller 1 and photographic fixing band is become evenly, so can prevent that photographic fixing is bad.
In addition, owing to temperature sensor 7 contacts with the surface of photographic fixing band, so capture heat by temperature sensor 7 from the photographic fixing band sometimes.Therefore, the part of temperature sensor 7 contact only, temperature is easy to step-down on the circumferencial direction of photographic fixing band.
In this example, as mentioned above, the parts 40 that are made of ferrite are being set, so compare the easier flux concentrating that makes in this part with other parts in this part.Therefore, the thermal value on this part increases than other parts.According to this configuration, can compensate the heat of capturing by temperature sensor 7, thereby the Temperature Distribution of photographic fixing belt surface is become evenly, so can prevent that photographic fixing is bad.
In addition, in this example, the interval of the back side iron core 9 of adjacency is narrowed down, can obtain even temperature and distribute, but also not necessarily be defined in this structure by end at heat generating roller 1.For example, the impartial and width of back side iron core 9 that makes the end that is positioned at heat generating roller 1 in the interval of the back side iron core 9 by making adjacency can obtain even temperature too and distribute greater than the width of the back side iron core 9 of the central portion that is positioned at heat generating roller 1.In addition, for example, the interval of the back side iron core 9 by making adjacency is impartial and dispose the parts that are made of ferrite independently in the scope near the end of heat generating roller 1, can obtain even temperature too and distribute.
[the 9th example]
Figure 23 is the perspective view of expression as the heat generating part of the fixing device of the image heating of the present invention's the 9th example, and Figure 24 is the sectional drawing of expression as the heat generating part of the fixing device of the image heating of the present invention's the 9th example.In addition, the member identical with above-mentioned the 4th example to function is marked with identical symbol, and its explanation is omitted.
As Figure 23, shown in Figure 24, different with above-mentioned the 4th example in this example, keeping being positioned at C shape iron core 32a, 32b in a movable manner near the back side iron core 9 at the position of the end of heat generating roller 1.Further, in this example, the recording chart of A3 size (wide 297mm) is used as the recording chart of breadth extreme, C shape iron core 32a, be positioned at the outside in the zone that the recording chart of A4 size (wide 210mm) passes through, when using the recording chart of approximate A4 size, shown in the dotted line 32a ' among Figure 24, make C shape iron core 32a along the moving radially of heat generating roller 1, and away from heat generating roller 1.When using the littler recording chart of size, the C shape iron core 32b of the inboard that is positioned at C shape iron core 32a is also moved by the same manner.
Other structures are identical with above-mentioned the 4th example.
In this example, the C shape iron core 32 in the outside in the zone that recording chart passes through is moved, thereby only the low air of the magnetoconductivity that magnetic flux passed through that is produced by coil current is partly increased in this part.Therefore, the magnetic flux of this part reduces, and makes the thermal value of the heat generating roller 1 of part minimizing relatively with it.According to this configuration, can prevent that the excessive temperature of the scope that recording chart does not pass through from rising, and can prevent that the temperature of members such as the photographic fixing band of end and bearing from surpassing heat resisting temperature.Further, even use the large scale recording chart after using undersized recording chart continuously, the temperature of photographic fixing portion is still normal, so can prevent the generation of thermal deviation.Therefore, after using undersized recording chart, can and then use the large scale recording chart.
In addition, in above-mentioned example, for example understand only C shape iron core 32 transportable situations, but also not necessarily be defined in this structure.For example, as shown in figure 25, C shape iron core 32a and central core 33 constituted one and it is moved shown in dotted line 9 ', also can obtain same effect.
In addition, in above-mentioned each example, field coil 5 contacts with back side iron core 9, even but between when being provided with gap about 1mm also can be obtained same effect.By between field coil 5 and back side iron core 9, this gap being set, can prevent that the field coil 5 and the temperature of the contact site of back side iron core 9 from rising.
In addition, in above-mentioned each example, heat insulating component 34 contacts with field coil 5, but also not necessarily is defined in this structure.For example, heat insulating component 34 and field coil 5 are separated, and constitute the air-flow between is passed through, thereby can further promote the heat radiation of field coil 5.
The structure of field coil 5, back side iron core 9, heat generating roller 1 is not limited to the structure of above-mentioned each example.As make that inductance L in the equivalent electrical circuit of Fig. 4 is more than the 10 μ H, below the 50 μ H, resistive component R is more than 0.5 Ω, below 5 Ω, then in practicality, there is not any problem.
In addition, in above-mentioned each example, for example understand and carry out the situation of excitation from the outside of heat generating roller 1 (generating component), but also can be the structure of carrying out excitation from the inside of heat generating roller 1 (generating component) by field coil 5.
[the 10th example]
Figure 26 is that expression will be used as the sectional drawing of the image processing system of fixing device as the image heating of the present invention's the 10th example.
In Figure 26, the 101st, Electrophtography photosensor (below, claim " photosensitive drums ").Photosensitive drums 101, one side is driven rotation with predetermined circumference speed along the direction of arrow, and one side makes its surface by negative dark potential V0 uniform charged by charger 102.
The 103rd, laser beam scanner, output is according to the laser beam of the electric digital pixel signal modulation of the time series of the picture information of importing from main device such as not shown image reading apparatus or computing machine.By the surface of the photosensitive drums 101 behind the mode uniform charged as mentioned above, by this laser beam flying exposure.Thus, make the current potential absolute value of the exposed portion of photosensitive drums 101 reduce and become bright current potential VL, thus the formation electrostatic latent image.This sub-image is developed by the electronegative toner of developer 104, becomes visible image.
Developer 104 has the developer roll 104a that is driven rotation.Developer roll 104a relatively disposes with photosensitive drums 101, and forms the thin layer of toner on its outer peripheral face.On developer roll 104a, apply its absolute value less than the dark potential V0 of photosensitive drums 101, greater than the development bias voltage of bright current potential VL, therefore, the toner on the developer roll 104a only carries out transfer printing to the part of the bright current potential VL of photosensitive drums 101, makes sub-image become visible image.
On the other hand, supply with recording chart 115 one by one from sheet feed section 110, and with its with and the accurate sequential of the rotational synchronization of photosensitive drums 101 be transported to roll gap portion between photosensitive drums 101 and the transfer roll 113 by a pair of contraposition roller 111,112.Then, by the transfer roll 113 that has applied transfer bias the toner picture on the photosensitive drums 101 is transferred on the recording chart 115 successively.Pass through the recording chart 115 of transfer printing portion, after separating from photosensitive drums 101, be transported to fixing device 116, thus the toner of transfer printing on recording chart 115 looked like to carry out photographic fixing.The recording chart 115 of toner picture after by photographic fixing is discharged on the discharge tray 117.
Make the photosensitive drums 101 after recording chart 115 separates, after by cleaning device 5 residues such as the residual toner of its lip-deep transfer printing being removed, use for image formation next time repeatedly.
Below, the fixing device as the image heating of this example is elaborated.
Figure 27 is the sectional drawing of expression as the fixing device of the image heating of the present invention's the 10th example, Figure 28 is the sectional drawing of the photographic fixing band that uses in the fixing device of expression the present invention the 10th example, Figure 29 is the field coil that uses in the fixing device of expression the present invention the 10th example and the front elevation of core, and Figure 30 is the sectional drawing of the heat generating roller that uses in the fixing device of expression the present invention the 10th example.
In Figure 27, Figure 28, the photographic fixing band 120 of thin thickness is the diameter 50mm that is made of polyamide of matrix material 121, the annular jointless band of thick 50 μ m.On the surface of photographic fixing band 120, be covered with the release layer 122 of the thick 5 μ m that constitute by fluorine resin, so that it has release property.As the material of matrix material 121, except that having stable on heating polyamide and fluorine resin etc., can also use the metals made from electrocasting as thin as a wafer such as nickel.As release layer 122, also can be used alone or as a mixture PTFE, PFA, FEP, silicon rubber, contain good resin or the rubber of release property such as fluororubber.When photographic fixing band 120 is used for the photographic fixing of monochrome image, only guarantee that release property gets final product, but, then preferably make it have elasticity as photographic fixing band 120 being used for the photographic fixing of color image, in this case, must further form thick rubber layer.
The 123rd, as the field coil of electro-heat equipment, this field coil 123 constitutes the section configuration that covers photographic fixing band 120.
As Figure 27, shown in Figure 29, on the part at the center of field coil 123 and the back side, the back side iron core 124 that is made of ferrite is set.And as the material of back side iron core 124, the deironing element is external, can also use the material of high permeabilities such as permalloy.In addition, the back side iron core 124 at field coil 123 back sides only exists on a part, makes it can capture leakage magnetic flux to the outside.Execute the alternating current of 30kHz to field coil 123 from field circuit 125.Below, the alternating current that also will put on field coil 123 is called " exciting current ".
As shown in figure 27, photographic fixing band 120, being suspended on by the surface with the tension force of regulation is on the heat generating roller 144 of the fixing roller 143 of low heat conductivity of the diameter 20mm that constitutes as the silicon rubber of rubber-like foams of soft (JISA30 degree) and the diameter 30mm that is made of hereinafter described material, and can rotate mobile in the direction of arrow B.Heat generating roller 144 is that the magnetic material of iron-nickel-chromium constitutes by the composition of thick 0.4mm, and its Curie point is adjusted into 220 ℃ according to the amount of the nickel that is mixed in the material.In the inside of heat generating roller 144, the conductive rollers 45 as electroconductive member of the thick 0.8mm of being separated by the gap of 0.5mm with heat generating roller 144 and being made of aluminium is being set.
As Figure 27, shown in Figure 30, heat generating roller 144 and conductive rollers 145 are used flange 146,147 supportings that are made of the little heat stable resin of heat conductivities such as phenolics at two ends.In addition, conductive rollers 145, disposing with the heat insulation mode of heat generating roller 144, thereby the heat that is produced by heat generating roller 144 is difficult to be delivered to conductive rollers 145.Heat generating roller 144 and conductive rollers 145 are that centre-driven is rotated by the drive unit of not shown device body with axle 148.
In Figure 27,, be that the silicon rubber of JIS A65 degree constitutes by hardness as the backer roll 149 of pressue device.And backer roll 149 is crimped on the fixing roller 43 across photographic fixing band 120, and forms roll gap portion therefrom.Here, backer roll 149, with respect to the throughput direction that is arranged on recording chart 115 under the vertical direction of fixing roller 43 a little by upstream side, along with moving of photographic fixing band 120, recording chart 115 at first contacts with backer roll 149.Backer roll 149 is supported to and can rotates around metal shaft 150 along with the rotation of photographic fixing band 120.And, also can use other heat stable resin or rubber as containing fluororubber, fluorine resin and so on as the material of backer roll 4.In addition, on the surface of backer roll 149, preferably cover resin or rubber such as PFA, PTFE, FEP separately or, to improve its wearing quality and release property with mixing.In addition, for preventing heat leakage, backer roll 149 preferably is made of the low material of thermal conductivity.
In this example,, can make heat generating roller 144 have the temperature automatic control characteristic by by constituting heat generating roller 144 as upper type.Below, with Figure 31, Figure 32 this effect is described.
In Figure 31, when the temperature of the heat generating part 144a relative of heat generating roller 144 with field coil 123 when Curie point is following, shown in arrow D, D ' among the figure, the magnetic flux that produces by exciting current, because the magnetic of heat generating roller 144 and major part runs through in the heat generating roller 144, and generate repeatedly and disappear.Induction current by the variation of this magnetic flux produces because of kelvin effect almost only flows through on the surface of heat generating roller 144, thereby produces Joule heat on this part.When the heat generating part 144a of heat generating roller 144 asymptotic Curie temperature, because magnetic disappears, so magnetic flux is all dispersed to a side of the conductive rollers 145 that is configured in heat generating roller 144 inside, thereby the induction current overwhelming majority is flowed out in the low conductive rollers 145 of resistance.At this moment, because the resistance of conductive rollers 145 is low, so, the generation of heat is significantly reduced by electric current is restricted to certain value.According to calculating, the electric current of this kelvin effect flows through the degree of depth of part, when the frequency of exciting current is approximately about 0.3mm during for 30kHz.As the thickness that makes heat generating roller 144 is equal to or greater than this skin depth, and the induction current major part is produced in heat generating roller 144.As improve faradic frequency, then skin depth reduces, and therefore can adopt the little heat generating roller of thickness 144.But when faradic frequency was too high, cost increased, and strengthened to the noise that send the outside.
In this example,, can realize about 190 ℃ stable temperature control by by constituting heat generating roller 144 as upper type.
In addition, in this example, adopted 2 layers of structure of heat generating roller 144 and conductive rollers 145, but not necessarily be defined in this structure.For example, also can adopt the heat generating roller that by 1 layer magnetic constitute thicker than skin depth.In this case, when being lower than Curie temperature, because the part that induction current flows through is thin thereby thermal value increases, when surpassing Curie point, induction current almost flows through on the whole thickness of magnetic, thus the resistance attenuating, thus thermal value is reduced.Therefore, even adopt this structure, also can obtain the temperature automatic control characteristic.
As mentioned above, as make the thickness of heat generating roller 144 be equal to or greater than the skin depth corresponding, then can obtain more significant temperature and control effect automatically with the frequency of the exciting current that puts on field coil 123.
In addition, in this example,, but also can adopt the aluminium high metal of electric conductivity such as copper in addition with the material of aluminium as conductive rollers 145.
In addition, in this example,, but when adopting other can set the alloy of Curie temperature, also can obtain same effect with the material of iron-nickel-chromium as conductive rollers 144.
To be installed in the image processing system shown in Figure 26 by the fixing device that constitutes as upper type, and make transfer printing as shown in figure 27 the recording chart 115 of toner picture enter fixing device so that be loaded with the face of toner 135 towards the mode of upside from the direction of arrow F, thereby with the toner on the recording chart 115 as photographic fixing.
According to this example, because heat generating roller 144 itself has the temperature automatic control characteristic, thus temperature is roughly controlled near the temperature of fixing temperature, and can not make heat generating part 144a reach unusual high temperature.This control is also worked to the local temperature difference of the depth direction (the turning axle direction of warm-up mill 144) of Figure 27, owing to make local heating functioin difference, so even the part of using undersized recording chart also recording chart is not passed through continuously reaches unusual high temperature, and, even use large-sized recording chart after this, can not produce thermal deviation yet.
In addition, the material of heat generating roller 144, thickness etc. can be set with the material of photographic fixing band 120, thickness etc. are independent respectively.Therefore, as material, the thickness of heat generating roller 144, can select to be suitable for most making its material, thickness with temperature automatic control characteristic.In addition, owing to the thermal capacity of photographic fixing band 120 also can be set with the thermal capacity of heat generating roller 1 is independent respectively, so can select optimum value as the thermal capacity of photographic fixing band 120.
In addition, fixing roller 143, not only the coefficient of heat conductivity of its material itself is low, and is made of foams, so, because there is the space in inside, thus the heat that photographic fixing band 120 is kept be difficult to because of with the loss that contacts of fixing roller 143, thereby can raise the efficiency.
In this example, for reaching the purpose that shortens heat time heating time, set the thermal capacity of photographic fixing band 120 as far as possible little, simultaneously thickness by reducing heat generating roller 144 and external diameter and its thermal capacity is set at very little value.When shown in this example, its thermal capacity being set at the value that equates with the thermal capacity of photographic fixing band 120 by the thickness that reduces heat generating roller 144 for accelerated warming, in a single day because the heat that stores in heat generating roller 144 is very little, so also can reduce immediately even in heat generating roller 144, stored common its temperature of heat.That is, thus former with the contact site of photographic fixing band 120 beyond the position to the method for heat generating roller 144 heat supplieds with 120 heating of photographic fixing band in, for photographic fixing band 120 is supplied with enough heats, heat generating roller 144 itself must be heated to quite high temperature.In addition, the photographic fixing band 120 that is cooled during by roll gap portion, according to by the time backer roll 149 and the temperature of fixing roller 143 and the state of temperature of recording chart 115, the temperature that is cooled has very big variant.Therefore, in said method, also must be correspondingly the temperature of heat generating roller 144 be set at widely different temperature.
Yet, in this example, owing to heat in the part that contacts with photographic fixing band 120 of heat generating roller 144, thereby required heat can be delivered to photographic fixing band 120 immediately, therefore the temperature of heat generating roller 144 need not be elevated to the value that surpasses necessity.In addition, near the heating hardly the position with the contact site of photographic fixing band 120 of having passed through of heat generating roller 144, so, being controlled at steady state value by temperature with this part, the temperature of photographic fixing band 120 that can be when entering roll gap portion remains at steady state value.Consequently, regardless of the state of temperature of backer roll 149 grades, can both carry out stable photographic fixing.
In addition, in this example, before arriving fixing roller 143, contact with recording chart 115 earlier, so can be with 135 fusings of the toner on the recording chart 115 under the state of the temperature that keeps necessity by the photographic fixing band 120 after heat generating roller 144 heating.Further, because the thermal capacity of photographic fixing band 120 is little, so when 120 beginnings of photographic fixing band contact with recording chart 115, recording chart 115 just begins to capture heat, therefore, when after recording chart 115 is by roll gap portion, separating, can make the temperature of photographic fixing band 120 fall quite lowly with photographic fixing band 120.Consequently, can prevent to produce thermal deviation.
In addition, in this example, heat generating roller 144 (heat generating part) is arranged on the inboard of photographic fixing band 120, and field coil 123 and back side iron core 124 is arranged on the outside of photographic fixing band 120, so, can prevent that field coil 123 grades are subjected to the temperature effect of heat generating part and heat up.Therefore, can make thermal value keep stable.
In addition, in this example, the matrix material of photographic fixing band 120 is made of resin, but also can constitute with metal without resin.In this case, the part of the heating that electromagnetic induction causes will take place in photographic fixing band 120, as make its thickness as thin as a wafer, then the magnetic flux that is produced by exciting current will connect photographic fixing band 120 and arrival heat generating roller 144, so that heat generating roller 144 can carry out controlling automatically with above-mentioned the same temperature.
In addition, in this example, heat generating roller 144 and conductive rollers 145 are disposed in heat insulation mode, even but the two is close to when configuration, can make heat generating roller 144 have the temperature automatic control characteristic too.In this case, will increase a little as the thermal capacity of heat generating roller 144, thereby correspondingly make heat time heating time elongated.
In addition, in this example, for example understand the situation that the surface of photographic fixing band 31 is controlled at the fixing temperature of regulation by the automatic control of the temperature of heat generating roller 144, but the temperature automatic control characteristic of heat generating roller 144 not necessarily only is applicable to this situation.For example, also can be by carrying out the control of fixing temperature with the detection of common thermistor etc., and set the temperature that the temperature of heat generating roller 144 is controlled automatically higher a little again, prevent the security of unusual intensification thereby use it for to guarantee device Yin Gaowen is damaged.
[the 11st example]
Below, with Figure 33 explanation the fixing device that color image is carried out photographic fixing as the image heating of the present invention's the 11st example.In addition, for playing a part same part with the structure identical with the fixing device of above-mentioned the 10th example, the explanation that it is detailed is omitted.
The 171st, field coil, the 172nd, back side iron core, field coil 171 and back side iron core 172, across photographic fixing band 150 with very little gap and heat generating roller 154 relative configurations.Back side iron core 172, its section configuration are E shape, and field coil 171 is wound on the protuberance of its central part.The same with above-mentioned the 10th example, by applying the exciting current that frequency is 30kHz from 175 pairs of field coils 171 of field circuit, make as the arrow G among the figure, the magnetic flux shown in the G ' and generate repeatedly and disappear, and be that heat generating part 154a is that excitation is carried out at the center, thereby produce vortex flow with the contact site of heat generating roller 154 and photographic fixing band 150.Therefore, make the heat generating part 154a heating of heat generating roller 154.At this moment, the vortex flow that produces in heat generating roller 154 concentrates on than by on the shallow surface of the skin depth of the frequency decision of the magnetoconductivity of heat generating roller 154 material therefors and intrinsic resistance and the exciting current that applied.When calculating according to the frequency of the characteristic of the used stainless steel material of heat generating roller 154 and the exciting current that applied, skin depth is about 0.3mm.Because with the thickness setting of heat generating roller 154 is 0.4mm, so most of heating all occurs in the thickness by the skin depth decision of the face side of heat generating roller 154.Therefore, local inhomogeneous even the thickness of heat generating roller 154 has, in heating, can not produce inhomogeneously yet, thereby can generate heat equably.In addition, because concentrating, heating occurs on heat generating roller 154 and contiguous surface photographic fixing band 150, so can expeditiously heat be passed to photographic fixing band 150.
Heat generating roller 154 passed through after the contact site with photographic fixing band 150 the position near on the part 154b, so that the surperficial state of contact of itself and heat generating roller 154 is being provided with a temperature sensor 158.And, according to the detection output of temperature sensor 158, by the output of control device 179 control field circuits 175.In this manner, thermal value is controlled, so that near the part 154b that has passed through the position after the contact site with photographic fixing band 150 of heat generating roller 154 remains stationary temperature.
The aforesaid fixing device of structure is installed in color image to be formed in the device (not shown), and make and formed color toner by the fast molten color toner that with the polyester is matrix material and enter fixing device from the direction of arrow H as 185 recording chart 186, thereby with the color toner on the recording chart 186 as 185 photographic fixing.
In this example, heating is carried out with contact site photographic fixing band 150 heat generating roller 154, and its heat can be delivered to photographic fixing band 150 immediately, surpasses necessary temperature so the temperature of heat generating roller 154 need not be elevated to.In addition, the temperature of the part 154b that has passed through the position after the contact site with photographic fixing band 150 by detecting heat generating roller 154 near is controlled thermal value, so the temperature of photographic fixing band 150 can be remained at the temperature that is suitable for photographic fixing most.
In addition, the photographic fixing band 150 that is cooled during by roll gap portion, according to by the time backer roll 157 and the temperature of fixing roller 153 and the state of temperature of recording chart 186, the temperature that is cooled has very big variant.But, since heating heat generating roller 154 carry out with contact site photographic fixing band 150 and thermal value controlled so that heat generating roller 154 passed through after the contact site with photographic fixing band 150 the position near the temperature maintenance of part 154b constant, so can stably control thermal value, and irrelevant with the temperature reduction of photographic fixing band 150.Therefore,, also there is no need to reduce and change the temperature control of heat generating roller 154, thereby the temperature of photographic fixing band 150 that can be when entering roll gap portion remains constant along with the temperature of photographic fixing band 150 even the thermal capacity of heat generating roller 154 is very little.
Further, in this example, because the thermal capacity of photographic fixing band 150 is little, so when 150 beginnings of photographic fixing band contact with recording chart 186, recording chart 186 just begins to capture heat, therefore, when after recording chart 186 is by roll gap portion, separating, can fall the temperature of photographic fixing band 150 quite low with photographic fixing band 150.Consequently, even the temperature of the photographic fixing band 150 will enter roll gap portion the time is set quite highly, also can prevent to produce thermal deviation.In this example, the temperature of the part 154b that has passed through the position after the contact site with photographic fixing band 150 by detecting heat generating roller 154 near is controlled thermal value, so can control the temperature of the first half of roll gap portion subtly.Therefore, even when adopting fast molten color toner 185, also can when making color toner 185 keep abundant molten state, carry out photographic fixing and can not produce thermal deviation.
In addition, near the heating hardly the position with the contact site of photographic fixing band 150 of having passed through of heat generating roller 154, so, be controlled at steady state value by temperature with this part, can the temperature of photographic fixing band 150 remain at steady state value when entering roll gap portion.Consequently, regardless of the state of temperature of backer roll 157 grades, can both carry out stable photographic fixing.
In addition, fixing roller 153, not only the coefficient of heat conductivity of its material itself is low, and is made of foams, so, because there is the space in inside, thus the heat that photographic fixing band 150 is kept be difficult to because of with the loss that contacts of fixing roller 153, thereby can raise the efficiency.Further, owing to set the hardness of fixing roller 153 more much lower, can make photographic fixing band 150 along backer roll 157 distortion in roll gap portion than the hardness of backer roll 157.Therefore, when recording chart 186 has passed through this roll gap portion, recording chart 186 can be extruded to the direction of leaving photographic fixing band 150, so fissility is very good.
Applicability on the industry
As mentioned above, according to the present invention, can realize when making the generating component heating required for obtaining Power the time need not to make magnet exciting coil to flow through the picture heater of big electric current, so, can use In considering to shorten heat time heating time and energy-conservation etc. electro-photography apparatus, electrostatic recording apparatus etc. The fixing device that uses in the image processing system.
Claims (12)
1. image heating, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, and make at the upwardly extending wire harness in the turning axle side of above-mentioned generating component and be close to mutually at a position at least;
The outside at field coil also has the iron core that is made of magnetic material;
Make the generating component of field coil peripheral part rotate the width that be recorded material of axial length, and make the generating component of iron core rotate the width that be recorded material of axial length greater than employed breadth extreme greater than employed breadth extreme.
2. image heating according to claim 1 is characterized in that: make from the iron core end face to the generating component end face to rotate axial distance along above-mentioned generating component longer than the relative spacing above-mentioned iron core and the generating component.
3. image heating according to claim 1 is characterized in that: iron core has obstructed overexcitation coil and relative with generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component.
4. image heating according to claim 3 is characterized in that: at least a portion of opposed portion is formed near portion near generating component more than magnetic conduction portion.
5. image heating according to claim 4 is characterized in that: be provided with a plurality of near portion and make above-mentioned a plurality of middle position that is positioned at field coil coiling near a position in the portion.
6. image heating according to claim 1 is characterized in that: generating component is formed tubulose, and make above-mentioned generating component inside perpendicular to the basal area of the face of turning axle maximum basal area less than iron core and field coil.
7. image heating according to claim 1, it is characterized in that: the outside at field coil also has the iron core that is made of magnetic material, above-mentioned iron core, have not by above-mentioned field coil and relative with above-mentioned generating component opposed and by above-mentioned field coil and the magnetic conduction portion relative with above-mentioned generating component, and make above-mentioned opposed portion rotate between the end of axial outermost end length less than the width of photographic fixing band along above-mentioned generating component.
8. image heating, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, and make at the upwardly extending wire harness in the turning axle side of above-mentioned generating component and be close to mutually at a position at least;
Also have cooling device with airflow cooling field coil.
9. image heating, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: above-mentioned field coil, by make boundling the wire harness of wire rod of surface insulation on the turning axle direction of above-mentioned generating component, extend and along the circumferential disc of above-mentioned generating component around forming, and make at the upwardly extending wire harness in the turning axle side of above-mentioned generating component and be close to mutually at a position at least;
Also have the heat insulating component of the transmission of between field coil and generating component, covering heat.
10. image heating according to claim 9, it is characterized in that: the outside at field coil also has the iron core that is made of magnetic material, and make above-mentioned field coil along generating component rotate axial length than heat insulating component along above-mentioned generating component rotate axial length short but than above-mentioned iron core to rotate axial length along above-mentioned generating component long.
11. image heating, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the side face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: the outside at above-mentioned field coil also has the iron core that is made of magnetic material, and make above-mentioned iron core rotate the width that be recorded material of axial length along above-mentioned generating component greater than employed breadth extreme.
12. image heating, have the generating component that constitutes by rotor, relatively dispose and make the field coil of above-mentioned generating component heating by electromagnetic induction with the outer peripheral face of above-mentioned generating component with magnetic and electric conductivity, this image heating is characterised in that: the outside at above-mentioned field coil also has the iron core that is made of magnetic material, and make above-mentioned iron core rotate the width that be recorded material of axial length along above-mentioned generating component greater than employed breadth extreme.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP54080/99 | 1999-03-02 | ||
| JP05408099A JP4303349B2 (en) | 1999-03-02 | 1999-03-02 | Image heating apparatus and image forming apparatus |
| JP297760/99 | 1999-10-20 |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB00807125XA Division CN1295573C (en) | 1999-03-02 | 2000-02-29 | Image heating device and image forming device used for same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1782921A true CN1782921A (en) | 2006-06-07 |
Family
ID=12960647
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200510126774 Pending CN1782921A (en) | 1999-03-02 | 2000-02-29 | Image heating device and image forming apparatus using the same |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP4303349B2 (en) |
| CN (1) | CN1782921A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103676566A (en) * | 2012-09-13 | 2014-03-26 | 富士施乐株式会社 | Fixing device and image forming apparatus |
| CN113396641A (en) * | 2019-07-24 | 2021-09-14 | 株式会社快乐福 | Heater for sealing treatment of secondary battery |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1640819B1 (en) | 1999-03-02 | 2013-02-20 | Panasonic Corporation | Image heating device for an image forming apparatus |
| GB2357461B (en) * | 1999-12-22 | 2002-05-08 | Matsushita Electric Ind Co Ltd | Fixing device |
| JP3795770B2 (en) | 2000-06-30 | 2006-07-12 | 株式会社リコー | Fixing apparatus and image forming apparatus |
| WO2002029498A1 (en) * | 2000-09-29 | 2002-04-11 | Matsushita Electric Industrial Co., Ltd. | Image heating device and image forming device |
| JP2002123106A (en) * | 2000-10-19 | 2002-04-26 | Matsushita Electric Ind Co Ltd | Fixing device |
| US6591082B2 (en) | 2000-12-22 | 2003-07-08 | Matsushita Electric Industrial, Co., Ltd. | Printer and fixing device which maintain a stable temperature for fixing a toner image |
| US6934483B2 (en) | 2002-02-28 | 2005-08-23 | Matsushita Electric Industrial Co., Ltd. | Image heating device, image forming apparatus, image copying machine, and method for controlling temperature |
| US6968137B2 (en) | 2002-02-28 | 2005-11-22 | Matsushita Electric Industrial Co., Ltd. | Image heating device, image forming apparatus, image copying machine, and method for controlling temperature |
| JP4756918B2 (en) | 2004-06-30 | 2011-08-24 | キヤノン株式会社 | Image heating device |
| US8036557B2 (en) | 2007-05-15 | 2011-10-11 | Kabushiki Kaisha Toshiba | Fixing device, image forming apparatus, and heating control method for fixing device |
| US7950652B2 (en) | 2007-06-19 | 2011-05-31 | Kabushiki Kaisha Toshiba | Sheet discharge apparatus, image forming apparatus and sheet discharging method |
| JP5428403B2 (en) * | 2008-05-23 | 2014-02-26 | 富士ゼロックス株式会社 | Fixing apparatus and image forming apparatus |
-
1999
- 1999-03-02 JP JP05408099A patent/JP4303349B2/en not_active Expired - Lifetime
-
2000
- 2000-02-29 CN CN 200510126774 patent/CN1782921A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103676566A (en) * | 2012-09-13 | 2014-03-26 | 富士施乐株式会社 | Fixing device and image forming apparatus |
| CN113396641A (en) * | 2019-07-24 | 2021-09-14 | 株式会社快乐福 | Heater for sealing treatment of secondary battery |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4303349B2 (en) | 2009-07-29 |
| JP2000250338A (en) | 2000-09-14 |
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