JPH10153917A - Heating roller and roller heating device - Google Patents

Abstract

(57) [Problem] To provide a heating roller and a roller heating device which prevent a short circuit of an electric wire forming a coil and are excellent in safety. SOLUTION: A hollow roller 34 made of a conductive member is provided.
And the heating roller 11 of the induction heating type having the coil 42 disposed inside the roller 34, the surface of the heating roller 11 is formed of an insulating material and has an uneven shape. Bobbin 4 located in
1 and the coil 42 has a concave portion 46 formed by unevenness so that a gap is formed between the electric wires of the coil 42.
Along the bobbin 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an induction heating type heating roller and a roller heating apparatus.

[0002]

2. Description of the Related Art A fixing device for fixing a toner image on transfer paper is used in an image forming apparatus to which an electrophotographic method is applied, such as an electrostatic copying machine, a printer, and a facsimile. As a fixing device, a fixing device having a heating roller having a heating unit therein and a pressure roller in contact with the heating roller is well known, and the fixing device heats a transfer paper on which a toner image is formed by a heating roller. The toner image is fixed on the transfer paper by passing through a contact portion between the toner image and the pressure roller. The degree of bonding of the toner to the transfer paper varies depending on the thermal conditions given by the fixing device. If more heat is applied, the toner melts well and has good fixability. Gets worse.

As a heating means for the heating roller, Japanese Patent Laid-Open No.
As described in JP-A-3-50844, an induction heating type heating method is known. The heating roller described in the gazette has a core made of a magnetic material fixed to a shaft,
A coil wound around the core, a roller member as an induction heating element rotatably supported on a shaft, and a heat-insulating layer disposed on the inner peripheral surface of the roller member. According to the roller, a current (generally, 5 to 15 A) from a commercial power supply is supplied to the coil to generate an induced current in the roller member, and a heating action is performed by Joule heat accompanying the induced current.

In the induction heating type, a coil is provided inside a roller member, and at the time of fixing, a high voltage is applied to the coil to supply a large current. Also,
The roller member that covers the coil is generally formed of a conductive material in order to generate Joule heat, and is often made of metal in terms of heat resistance and the like.

[0005]

In the above-mentioned heating means, the electric wire forming the coil is usually covered with an insulating layer. However, when the temperature between the coil and the roller member becomes high due to the heat generated by the induced current, a part of the insulating layer may be melted by heat. When a part of the insulating layer is melted and the conductor of the electric wire is exposed and the conductors come into contact with each other, a short circuit occurs. Therefore, it is conceivable to use a wire in which the conductor is covered with an insulating layer having heat resistance to withstand high temperatures for the wire of the coil, but the coating that satisfies the insulation and heat resistance is a special coating. It is very expensive. Therefore, there is a problem that the cost of the electric wire increases.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a heating roller and a roller heating device which prevent a short circuit of an electric wire forming a coil and are excellent in safety.

[0007]

According to the first aspect of the present invention,
In an induction heating type heating roller having a hollow roller formed of a conductive member and a coil disposed inside the roller, the heating roller is formed of an insulating material and has a surface formed in an uneven shape. And a bobbin disposed inside the coil, wherein the coil is wound around the bobbin along a concave portion formed by irregularities so that a gap is generated between electric wires of the coil. is there.

According to a second aspect of the present invention, there is provided a hollow roller formed of a conductive member, a coil disposed inside the roller, and a pressure roller in contact with the roller, and supplies power to the coil. In an induction heating type roller heating device in which a roller is heated by generating an induction current in a roller and a sheet is passed between the rollers, the roller is formed of an insulating material and has an uneven surface. , A bobbin disposed inside the coil, and the coil is wound around the bobbin along a concave portion formed by irregularities so that a gap is formed between electric wires of the coil. .

According to a third aspect of the present invention, in the heating roller according to the first aspect or the roller heating apparatus according to the second aspect, the unevenness is formed by a spiral groove extending from one end to the other end of the bobbin. Configuration.

The invention according to claim 4 is the invention according to claim 1 or 3.
4. The heating roller according to claim 2, wherein the distance from the outer peripheral surface of the coil to the tip end surface of the projection formed by the unevenness is H (mm). This is a configuration that satisfies the relationship of 3 (mm).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings. First, a description will be given of a fixing device of an image forming apparatus to which the heating roller and the roller heating device of the present invention are applied. In FIG. 1, reference numeral 10 denotes a fixing device of the image forming apparatus. The fixing device 10 includes an induction heating type heating roller 11 therein, a pressure roller 12 abutted against the heating roller 11 by a pressure unit (not shown), and a heating roller 1.
A cleaning roller 13 which is in contact with the cleaning roller 1 and removes toner and paper dust adhering to the heating roller 11; a blade 14 which comes into contact with the cleaning roller 13 and scrapes off the adhered matter such as toner adhering to the cleaning roller 13; Felt 17 for applying release agent 21 to outer peripheral surface of roller 11
The transfer paper P on which the toner image has been fixed by the release agent blade 18 for scraping off the excess release agent of the release agent 21 applied by the felt 17 and the heating roller 11 and the pressure roller 12. It mainly includes a peeling claw 19 that is separated from the heating roller 11, and a pair of discharge rollers 20 a and 20 b that discharge the transfer paper P separated by the peeling claw 19.

A thermistor 26 for detecting the temperature of the heating roller 11 is disposed near the surface of the heating roller 11. The temperature information of the thermistor 26 is input to a power supply unit (not shown), and the power supply unit controls the amount of power supplied to the heating roller 11 based on the temperature information of the thermistor 26 to maintain the temperature of the heating roller 11 at a predetermined temperature.

As shown in FIG. 2, the heating roller 11 has a hollow roller portion 30 forming an outer peripheral portion of the heating roller 11.
And a core section 40 provided inside the roller section 30.

The core 40 includes a bobbin 41 made of an insulating material, an induction coil 42, electrodes 43a and 43b for supplying power to the induction coil 42, and lead wires 44a and 44b for supplying power to the electrodes 43a and 43b, respectively. It is mainly composed of

The bobbin 41 is formed in a cylindrical shape, and its central portion in the axial direction is formed as a large-diameter portion 410. Small-diameter portions 411a, 41 are provided at both ends of the large-diameter portion 410.
1b are respectively formed.

The outer ends of the small diameter portions 411a and 411b are
The fixing device 10 is fixed to side plates (not shown). Inside the small diameter portions 411a and 411b, columnar electrodes 43a and 43b are provided, respectively. Electrode 43
Fixing members 47, 47, which will be described later, are connected to the inner ends of the electrodes 43a, 43b, that is, to the respective ends within the large diameter portion 410 of the electrodes 43a, 43b. Electrodes 43a, 4
Lead wires 44a and 44b are screwed on the outer end surface of 3b.
Respectively. Lead wires 44a, 4
4b is connected to the power supply means, and the power supply means controls the power supply amount.

On the surface of the large-diameter portion 410, a spiral groove 46 that is continuous from one end of the large-diameter portion 410 to the other end is formed. As shown in FIG. 3, the shape of the groove 46 is substantially the same as the outer peripheral shape of the induction coil 42, and the depth of the groove 46 is substantially the same as the radius of the electric wire of the induction coil 42. The interval between the grooves 46 is set to approximately 0.3 mm. The grooves 46 form irregularities on the surface of the large-diameter portion 410.

In the large diameter portion 410, the induction coil 42 is
6 is wound along. Both ends of the induction coil 42 are caulked to fixing members 47 provided on the outer peripheral surfaces of both ends of the large diameter portion 410, respectively. The fixing members 47, 47 are made of a conductive material, and are connected to the electrodes 43a, 43b, respectively, as described above.

The small diameter portions 411a, 411b of the bobbin 41 are supported by the support tubes 32a, 32 via rolling bearings 31, 31, respectively.
b are rotatably supported. Support tube 32
a, 32b have flanges 33a, 3
3b, a cylindrical roller 34 is disposed between the flanges 33a and 33b. Both ends of the roller 34 and the flanges 33a and 33b are fitted to each other, and the roller 34 is connected to the roller 34 by a screw (not shown). Each flange 33a, 33
b are fixed to each other.

The roller 34 is a magnetic member having conductivity,
For example, a core metal member 340 formed of iron, stainless steel, or the like, and a release layer 341 formed on the outer peripheral surface of the core metal member 340 and formed of a resin that improves the releasability of the toner T are provided. I have. The roller unit 30 includes a roller 34 and support tubes 32a and 32b.

A gear 35 is fixed to the support tube 32a, and a drive gear (not shown) is meshed with the gear 35. When the gear 35 is rotated by the drive gear, the roller unit 30 rotates around the bobbin 41. Pressure roller 12
Is a metal core 12 made of, for example, an aluminum alloy.
0, and a rubber layer 121 made of silicon rubber wound around the outer peripheral surface of the cored bar 120.

The operation of the above configuration will be described. Since the electric wire of the induction coil 42 is wound along the spiral groove 46 formed on the surface of the bobbin 41, the movement of the electric wire of the induction coil 42 is restricted, and contact between the electric wires is prevented. . Therefore, even if the coating of the insulating layer of the electric wire is melted or damaged to expose the conductor of the electric wire, a short circuit due to contact between the conductors can be prevented, and the safety of the device can be improved. In addition, it is generally known that inexpensive electric wires have low heat resistance.
Since a short circuit due to contact between the wires can be prevented, the induction coil 42 can be used stably, and the cost of the wires can be reduced.

In the present embodiment, the continuous spiral groove 46 is formed on the surface of the large diameter portion 410. However, if the induction coil 42 is prevented from being separated from the groove 46, the groove 46 may be used. May be an intermittent groove.

Next, the operation of the fixing device 10 will be briefly described. As shown in FIG. 1, when the transfer paper P on which the toner image of the document has been transferred is sent to the fixing device 10, the power supply means applies a large current from a commercial power supply to the lead wires 44a, 44b,
Electric power is supplied to the induction coil 42 via 3a, 43b and the fixing members 47, 47. An induced current is generated in the roller 34 by supplying power to the induction coil 42, and the heating roller 11 is heated to a predetermined temperature by Joule heat accompanying the induced current.
Thereafter, the transfer paper P is inserted between the heating roller 11 heated to a predetermined temperature and the pressure roller 12, and the toner image is heated and fixed on the transfer paper P. The transfer paper P on which the toner image has been transferred is separated from the surface of the heating roller 11 by the peeling claw 19, conveyed by the pair of paper discharge rollers 20a and 20b, and discharged to the outside of the fixing device 10.

Next, a second embodiment is shown in FIGS.
This embodiment will be described. In the second embodiment,
Since the shape of the large diameter portion 410 of the bobbin 41 in the first embodiment is different, only the shape of the large diameter portion will be described. In FIGS. 4 and 5, the same members as those shown in FIGS. 2 and 3, and the description thereof is omitted.

As shown in FIG. 4, the large diameter portion 4 of the bobbin 41
A spiral ridge 50 is integrally formed on one surface of the large diameter portion 410 from one end to the other end. Ridge 5
The groove 51 is formed by the gaps between 0, that is, the mutually facing surfaces of the ridges 50 and the outer peripheral surface of the large diameter portion 410. Along this groove 51, the induction coil 42
It is wound around 10.

In FIG. 5, the width of the groove 51 is W (mm),
When the distance from the outer peripheral surface of the induction coil 42 to the outer end surface of the ridge 50 in the groove 51 is H (mm) and the diameter of the electric wire of the induction coil 42 is R (mm), the width W of the groove 51 is W
(Mm)> R (mm), where the distance H is H (mm)
Each is set so as to satisfy the relationship of ≧ 3 (mm). At this time, the depth H1 (mm) of the groove 51 is
H1 (mm) ≧ 3 (mm) + R (mm).

With the above configuration, even if the bobbin 41 vibrates, the movement of the electric wire of the induction coil 42, that is, the detachment of the electric wire from the groove 51 is reliably prevented.
Safety standards such as A can be satisfied, and the safety of the device can be maintained. Further, in the present embodiment, the groove 51 is formed by the ridge 50, but the same effect can be obtained by extending the depth of the groove 46 in the first embodiment.

Next, a third embodiment is shown in FIG. 6, and this embodiment will be described. Also in the third embodiment, the shape of the large diameter portion 410 of the bobbin 41 in the first embodiment is different, so only the shape of the large diameter portion will be described, and in FIG. 6, the same as the members shown in FIG. The same reference numerals as in FIG. 2 denote the same members, and a description thereof will be omitted.

As shown in FIG. 6, the large diameter portion 4 of the bobbin 41
A large number of protrusions 55 are provided on the surface of 10 at equal intervals radially from the center of the large diameter portion 410. The large number of protrusions 55 are spirally arranged on the surface of the large diameter portion 410 to guide the electric wire of the induction coil 42 in a spiral shape.
The electric wire of the induction coil 42 is sewn between the protrusions 55 so that the electric wires of the induction coil 42 do not contact with each other,
It is wound around the surface of the large diameter portion 410. The height of each projection 55 has such a height that the movement of the induction coil 42 is prevented. If the electric wire of the induction coil 42 is wound around the surface of the large diameter portion 410 so that the electric wire does not come into contact with each other, the protrusion 55 may be provided at random on the surface of the large diameter portion 410.

[0031]

As described above, claim 1 or claim 2
According to the invention, the bobbin is formed of an insulating material, the surface of the bobbin is formed in an uneven shape, and the coil is wound along the recess so that a gap is generated between electric wires of the coil. Therefore, the movement of the electric wire of the coil is regulated, and the contact between the electric wires is prevented. Therefore, even when the conductor of the electric wire is exposed due to erosion of the covering of the electric wire, a short circuit due to contact between the conductors of the electric wire can be prevented, and the safety of the device can be improved.

Further, even if an expensive electric wire satisfying insulation and heat resistance is not used, a short circuit due to contact between the electric wires is prevented, so that the coil can be used stably and the cost of the electric wire can be reduced. it can.

According to the third aspect of the present invention, the spiral groove extending from one end to the other end of the bobbin forms the unevenness on the surface of the bobbin, so that the coil is wound around the bobbin. It can be done easily.

According to the fourth aspect of the present invention, the distance from the outer peripheral surface of the coil to the tip end surface of the projection formed by the unevenness is H.
(Mm), the relationship of H (mm) ≧ 3 (mm) is satisfied, so that even if the bobbin vibrates, the coil is reliably prevented from coming off the concave portion of the electric wire. Therefore, safety standards such as UL and CSA can be surely satisfied, and the safety of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a fixing device to which the present invention is applied.

FIG. 2 is a sectional view of a heating roller according to the first embodiment of the present invention.

FIG. 3 is an enlarged sectional view of a large diameter portion of the bobbin of FIG.

FIG. 4 is a partially cutaway front view of a core part according to a second embodiment of the present invention.

5 is an enlarged sectional view of a large diameter portion of the bobbin in FIG.

FIG. 6 is a front view of a bobbin showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Fixing apparatus 11 Heating roller 12 Pressure roller 30 Roller part 34 Roller 40 Core part 41 Bobbin 410 Large diameter part 411a, 411b Small diameter part 42 Induction coil 46, 51 Groove 50 Projection 55 Projection H Outer end surface of a projection from an induction coil. Distance to H1 Groove depth R Diameter of induction coil wire

Claims (4)

[Claims] An induction heating type heating roller having a hollow roller formed of a conductive member and a coil disposed inside the roller, wherein the heating roller is formed of an insulating material and has an uneven surface. A bobbin that is formed in the shape of the coil and has a bobbin disposed inside the coil, and the coil extends along the concave portion formed by the irregularities so that a gap is generated between electric wires of the coil. A heating roller wound around a bobbin. 2. A roller having a hollow roller formed of a conductive member, a coil disposed inside the roller, and a pressure roller in contact with the roller. In an induction heating type roller heating device that generates an induction current to heat the roller and pass a sheet between the two rollers, the roller heating device is formed of an insulating material, and has a surface with an uneven shape, A bobbin disposed inside the coil, wherein the coil is wound around the bobbin along a concave portion formed by the irregularities so that a gap is formed between electric wires of the coil. A roller heating device, characterized in that: 3. The heating roller according to claim 1, wherein the unevenness is formed by a spiral groove extending from one end to the other end of the bobbin. Heating equipment. 4. When the distance from the outer peripheral surface of the coil to the tip end surface of the projection formed by the unevenness is H (mm), the relationship of H (mm) ≧ 3 (mm) is satisfied. The heating roller according to claim 1 or 3, or the roller heating device according to claim 2 or 3.