JP2002025759A - Heating device and image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device and image-forming device for transporting a material to be recorded in a pinched state, pressurize a material to be heated and heat it up, whereby such conventional problems are well solved that a lubricant is swept away from between a fixing film and sliding member owing to the pressurizing force for forming a nip part for fixing and will not substantially remain in a slide part mating with the nip part, causing the tight attachment force between the fixing film and slide plate to increase at low temperature conditions, for example at room temperature, and the torque to rise, which should result in detuning of a drive roller (drive motor) or inconvenience, such as a jam originating from a film slippage. SOLUTION: The heating device includes a contacting part, formed by abutting of a heating rotor with a pressurizing member and therewith transports the material to be recorded in a pinched state, pressurizes the material to be heated and heats, where the heating rotor is furnished at the inner surface with a recess for retaining the lubricant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for pressurizing a material to be heated.
An electrophotographic apparatus comprising: a heating device for heating; and an image heating device for heating and fixing an unfixed image formed and supported on a recording material, which is a heating material, to the recording material.
The present invention relates to an image forming apparatus such as an electrostatic recording device.

[0002]

2. Description of the Related Art For convenience, an image heating apparatus (fixing apparatus) in which a conventional heating apparatus is provided in an image forming apparatus such as a copying machine or a printer and heats and fixes a toner image on a recording material will be described as an example. In the image forming apparatus, a recording material (transfer material sheet, electrofax sheet, electrostatic recording paper, OHP sheet, printing paper, etc.) is used in an appropriate image forming process means such as an electrophotographic process, an electrostatic recording process, and a magnetic recording process. A heat roller type device is used as a fixing device for heating and fixing an unfixed image (toner image) of the target image information formed and carried on a format paper or the like by a transfer method or a direct method as a permanent fixed image on a recording material surface. Was widely used. Recently, a film heating type apparatus has been put into practical use from the viewpoint of quick start and energy saving. Also, an electromagnetic induction heating system has been proposed. a) Heat roller method This heat roller method basically has a pressure roller pair of a fixing roller (heating roller) and a pressure roller, and rotates the pressure roller pair to form a nip that is a mutual pressure contact portion of the pressure roller pair. A recording material carrying an unfixed toner image to be fixed in a fixing nip portion (heating nip portion) is introduced and conveyed by nipping and transporting the recording material. This is to fix the applied toner image on the surface of the recording material by heat and pressure.

In general, a fixing roller has a hollow metal roller made of aluminum as a base (metal core), and a halogen lamp as a heat source is inserted and disposed in the hollow space thereof. Is controlled by controlling the energization of the halogen lamp so that the fixing temperature is maintained.

In particular, as a fixing device of an image forming apparatus for forming a full-color image, which is required to have a capability of sufficiently heating and melting a maximum of four toner image layers to mix colors,
If not sufficiently heated to the interface between the recording material and the toner layer, a fixing failure occurs, so the core of the fixing roller has a high heat capacity, and the toner image is wrapped around the core and melted uniformly. A rubber elastic layer for
The toner image is heated via the rubber elastic layer. There is also a configuration in which a heat source is provided in the pressure roller so that the pressure roller is also heated and controlled in temperature.

B) Film heating system A film heating system fixing device is disclosed, for example, in Japanese Patent Application Laid-Open No. 63-313182.
JP-A-2-15778 / JP-A-4-44075
And Japanese Patent Application Laid-Open No. 4-204980. That is, a film, that is, a heat-resistant film (fixing film) is sandwiched between a ceramic heater as a heating element and a pressure roller as a pressure member to form a nip portion. By introducing a recording material on which an unfixed toner image to be image-fixed to be formed and supported is introduced between the rollers and nipped and transported together with the film,
In the nip portion, the heat of the ceramic heater is applied to the recording material via the film, and the unfixed toner image is heat-pressure fixed on the recording material surface by the pressing force of the pressure roller in the nip portion.

The fixing device of the film heating type can constitute an on-demand type device using a ceramic heater and a member having a low heat capacity as a film, and a ceramic as a heat source only when an image is formed by an image forming apparatus. What is necessary is just to energize the heater to generate heat to a predetermined fixing temperature, the waiting time from the power-on of the image forming apparatus to the image forming executable state is short (quick start property), and the power consumption during standby is large. Has the advantage of being small (power saving). c) Electromagnetic induction heating method Japanese Patent Application Laid-Open No. Hei 7-114276 proposes a heating device that generates an eddy current in the film itself or a conductive member close to the film and generates heat by Joule heat. In the electromagnetic induction type film heating method, the heating area can be made closer to the object to be heated, so that the efficiency of energy consumption can be increased.

In the above-described film heating type heating apparatus, a method of driving a cylindrical or endless film as a heating rotator includes a film pressed by a pressure roller and a film guide for guiding the inner peripheral surface of the film. Driven by the rotation of the pressure roller (pressure roller driving method), or conversely, the pressure roller is driven and rotated by driving an endless film-like film stretched by a driving roller and a tension roller ( Pressure roller driven system).

[0008] A lubricant such as heat-resistant grease is interposed between the inner surface of the film and the film guide in order to reduce the influence of rotational torque due to friction between the film and the film guide.

In a film heating type heating device,
As proposed in JP-A-5-27619,
By interposing a lubricant (grease) between the film and the film support member, the slidability between the film and the film guide has been ensured.

[0010]

In a fixing device of a film heating type as a conventional heating device, heat-resistant grease is applied to a sliding surface because an inner surface of a film and a film guide slide at a fixing nip portion. However, when the fixing belt rotates, the pressing force for forming the fixing nip portion causes the lubricant to be swept out from between the fixing film and the sliding member. Did not remain. Therefore, at low temperatures such as room temperature, the adhesion between the fixing film and the sliding plate increases, and the torque increases due to durability. This causes problems such as step-out of the motor driving the drive roller and fixing jam due to fixing film slip. was there.

The present invention has been made to solve the above-mentioned conventional problems, and has as its object to suppress the torque at the time of starting rotation at a low temperature such as room temperature.

[0012]

According to the present invention, there is provided a heating apparatus and an image forming apparatus having the following constitution.

(1) a rotating member, a pressing member for pressing the rotating member, and a supporting member for supporting the rotating member;
The support member has a sliding portion with an inner surface of the rotating body at a portion corresponding to a contact portion formed by contact between the rotating body and the pressing member, and the rotating body, the pressing member, A heating device for pressing and heating a material to be heated by sandwiching and transporting the material to be heated by a contact portion formed by the abutment, wherein a concave portion is provided on the inner surface of the rotating body.

(2) The heating device according to (1), wherein a concave portion is provided in a groove shape on the inner surface of the rotating body.

(3) The heating device according to any one of (1) and (2), wherein a plurality of independent concave portions are provided on the inner surface of the rotating body.

(4) The angle between the groove-shaped recess and the longitudinal direction of the rotating body is θm, and the longitudinal direction of the rotating body is 0 m.
The heating device according to any one of (1) to (3), wherein, when ゜, 5 ° ≦ | θm | ≦ 60 ° is satisfied.

(5) When the length of the rotating body is L _F , the length of the recess is L _B , and the length of the pressing member is L _R , L _F > L _B heating apparatus according to any one of which is characterized by satisfying the ≧ L _R (1) to (4).

[0018] (6) in the longitudinal length L _B of the recesses are formed of the rotating body surface, the area of the recess 10-6
The heating device according to (5), wherein the heating device is formed so as to occupy 0%.

(7) The recess has a width of 0.1 to 1 mm, a depth of 0.005 mm or more, and a length less than the width of the sliding portion with respect to the rotation direction of the rotating body. The heating device according to any one of (1) to (6).

(8) The rotating body has a plurality of layers made of different materials, and the concave portion has a thickness of 5 to 2 with respect to the thickness of the innermost layer.
The heating device according to any one of (1) to (7), wherein the heating device is formed in a range of 0%.

(9) In the configuration in which a lubricant is interposed between the rotating body and the sliding portion, the recess holds the lubricant. A heating device as described.

(10) The heating device according to any one of (1) to (9), wherein the rotating body is an endless film having flexibility.

(11) The rotating body is made of an electromagnetic induction heating member, and has a magnetic field generating means for applying a magnetic field to the electromagnetic induction heating member to generate heat. A heating device according to any one of the above.

(12) The heating device according to any one of (1) to (10), wherein the rotating body is made of a heat-resistant film, and the heating body heats the material to be heated via the heat-resistant film.

(13) The material to be heated is a recording material on which an unfixed image is formed and carried, and the apparatus is a heat fixing device for heating and fixing the unfixed image on the recording material (1).
The heating device according to any one of (1) to (12).

(14) An image forming means for forming and carrying an unfixed image on the recording material, and a fixing means for fixing the unfixed image formed and carried on the recording material, wherein the fixing means (1) to ( 1
An image forming apparatus, which is the heating apparatus according to any one of 3).

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (1) Example of Image Forming Apparatus FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus in which a heating device according to the present invention is applied as an image heating device (fixing device). It is. The image forming apparatus of this example is an electrophotographic color printer. In FIG. 1, reference numeral 101 denotes a photoconductor drum (image carrier) made of an organic photoconductor or an amorphous silicon photoconductor, and is driven to rotate counterclockwise as indicated by an arrow at a predetermined process speed (peripheral speed).

The photosensitive drum 101 undergoes a uniform charging process of a predetermined polarity and potential by a charging device 102 such as a charging roller during its rotation. Next, the charged surface is subjected to a scanning exposure process of target image information by a laser beam 103 output from a laser optical box (laser scanner) 110.

The laser optical box 110 is modulated (on / off) according to a time-series electric digital pixel signal of target image information from an image signal generator such as an image reader (not shown).
Photoreceptor drum 1 that rotates by outputting the converted laser beam 103
The surface 01 is scanned and exposed to form an electrostatic latent image corresponding to the target image information. Reference numeral 109 denotes a mirror that deflects the output laser light from the laser optical box 110 to the exposure position of the photosensitive drum 101. In the case of full-color image formation, scanning exposure and latent image formation are performed on a first color-separated component image of a target full-color image, for example, a yellow component image. Is developed as a yellow toner image by the operation of the container 104Y. The yellow toner image includes a photosensitive drum 101 and an intermediate transfer drum 1 that rotates in a direction opposite to the photosensitive drum.
Primary transfer portion T1 which is a contact portion (or a close portion) with the first transfer portion 05
Is transferred onto the surface of the intermediate transfer drum. After the transfer of the toner image to the surface of the intermediate transfer drum 105, the surface of the photosensitive drum 101 is cleaned by the cleaner 107 after removing the remaining residue such as toner remaining after transfer.

The process cycle of charging, scanning exposure, development, primary transfer, and cleaning as described above performs the second color separation component image (eg, magenta component image,
The magenta developing device 104M is activated), the third color-separated component image (for example, the cyan component image, the cyan developing device 104C is activated), and the fourth color-separated component image (for example, the black component image, the black developing device 104BK is activated). Each color separation component image is sequentially executed, and four toner images of a yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are sequentially superimposed and transferred onto the surface of the intermediate transfer drum 105, and a desired full-color image is transferred. Are synthesized and formed.

The intermediate transfer drum 105 is a metal drum 1
05a on the medium resistance elastic layer 105b and the high resistance surface layer 10
5c, is rotated clockwise as indicated by an arrow at substantially the same peripheral speed as the photosensitive drum 101 in contact with or close to the photosensitive drum 101, and a bias potential is applied to the metal drum 105a of the intermediate transfer drum 105. And the toner image on the photosensitive drum 101 side is transferred to the surface of the intermediate transfer drum 105 by a potential difference from the photosensitive drum 101.

The color toner image synthesized and formed on the surface of the intermediate transfer drum 105 is
In a secondary transfer portion T2, which is a contact nip portion between the transfer roller 05 and the transfer roller 106, the image is transferred onto the surface of the recording material P fed at a predetermined timing from a sheet feeding portion (not shown).

The transfer roller 106 sequentially transfers the composite color toner images collectively from the surface of the intermediate transfer drum 105 to the recording material P by supplying charges of the opposite polarity to the toner from the rear surface of the recording material P. The recording material P that has passed through the secondary transfer portion T2 is separated from the surface of the intermediate transfer drum 105, introduced into the image heating device (fixing device) 100, and subjected to a heat fixing process of an unfixed toner image to form a color image. The paper is discharged as a material to a paper discharge tray (not shown) outside the machine.

After the transfer of the color toner image onto the recording material P, the intermediate transfer drum 105 is cleaned by the cleaner 108 after removing the residual toner such as untransferred toner and paper dust. The cleaner 108 is normally kept in a non-contact state with the intermediate transfer drum 105, and is kept in contact with the intermediate transfer drum 105 in the process of performing the secondary transfer of the color toner image from the intermediate transfer drum 105 to the recording material P. Is held.

The transfer roller 106 is always kept in a non-contact state with the intermediate transfer drum 105, and during the secondary transfer of the color toner image from the intermediate transfer drum 105 to the recording material P, the intermediate transfer member Drum 10
5 is held in contact with the recording material P via the recording material P. A print mode for a monochrome image such as a black and white image can also be executed.
Also, a double-sided image print mode or a multiple image print mode can be executed.

In the case of the double-sided image print mode, the recording material P on which the first-side image has been printed out of the image heating device 100 is printed.
Is turned upside down via a recirculation transport mechanism (not shown), is sent again to the secondary transfer portion T2, receives the toner image transfer on the two surfaces, and is again introduced into the image heating device 100 and
By receiving the fixing process of the toner image on the surface, a double-sided image print is output.

In the case of the multi-image print mode, the recording material P on which the first image has been printed out of the image heating device 100 is printed.
Is transferred to the secondary transfer unit T2 again without being turned over via a recirculation transport mechanism (not shown), receives the second transfer of the toner image on the surface on which the first image has been printed, and returns to the image heating device 100 again. The multi-image print is output by being subjected to the second toner image fixing process after being introduced.

(2) Image Heating Apparatus (Fixing Apparatus) 100 FIG. 2 is a cross-sectional model view of a main part of the electromagnetic induction heating system exemplified as the image heating apparatus 100, FIG. Is a longitudinal model diagram of the main part. The magnetic field generating means 15 includes a magnetic core 17 and an exciting coil 18. The magnetic core 17 is a member having a high magnetic permeability, and is preferably made of a material used for a transformer core, such as ferrite or permalloy, and more preferably a ferrite having a small loss even at 100 kHz or more.

The exciting coil 18 is a bundle (bundle) of a plurality of copper thin wires, each of which is insulated and coated, one by one as a conductive wire (electric wire) constituting a coil (wire loop).
This is wound a plurality of times to form an exciting coil. In this example, the exciting coil 18 is formed by winding 10 turns. As the insulating coating, a coating having heat resistance is preferably used in consideration of heat conduction due to heat generation of the fixing film 10. In this embodiment, a coating with polyimide is used, and the heat-resistant temperature is 220 ° C. Here, the density may be improved by applying pressure from the outside of the exciting coil 18.

An insulating member 19 is provided between the magnetic field generating means 15 and the fixing film 10. As the material of the insulating member 19, a material having excellent insulation properties and good heat resistance is preferable. For example, phenol resin, fluororesin (PFA resin, PTF
(E resin, FEP resin), polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, PES resin, PPS resin, LCP resin, and the like.

As shown in FIG. 5, an excitation circuit 27 is connected to the power supply sections 18a and 18b of the excitation coil 18. The excitation circuit 27 can generate a high frequency of 20 kHz to 500 kHz by a switching power supply. The exciting coil 18 generates an alternating magnetic flux by an alternating current (high-frequency current) supplied from the exciting circuit 27.

FIG. 6 is a diagram schematically showing the appearance of the generation of the alternating magnetic flux. FIG. 6A is a state diagram of the alternating magnetic flux C guided to the electromagnetic induction heating layer 1 and the magnetic cores 17a, 17b, 17c. (B) is a graph showing a part of the alternating magnetic flux. The alternating magnetic flux C guided to the magnetic cores 17a, 17b, 17c generates an eddy current in the electromagnetic induction heating layer 1 of the fixing film 10. This eddy current generates Joule heat (eddy current loss) in the electromagnetic induction heating layer 1 due to the specific resistance of the electromagnetic induction heating layer 1. The heat value Q here is determined by the density of the magnetic flux passing through the electromagnetic induction heating layer 1 and has a distribution as shown in the graph of FIG. The vertical axis represents the heat value Q in the electromagnetic induction heating layer 1 of the fixing film 10.

Here, the heating area H is defined as an area where the heating value is Q / e or more, where Q is the maximum heating value. this is,
This is the area where the amount of heat required for fixing can be obtained. The temperature of the fixing nip N is controlled such that a predetermined temperature is maintained by controlling the current supply to the exciting coil 18 by a temperature control system including a temperature detection unit (not shown). Reference numeral 26 denotes a temperature sensor such as a thermistor for detecting the temperature of the fixing film 10. In this example, the temperature of the fixing nip N is controlled based on the temperature information of the fixing film 10 measured by the temperature sensor 26. I have.

The pressure roller 30 as a pressure member is composed of a core metal 30a and a heat-resistant / elastic material layer of silicone rubber, fluoro rubber, fluoro resin, or the like which is formed and coated concentrically around the core metal in a roller shape. 30b, and the core metal 3
Both ends of Oa are rotatably supported and held between sheet metal (not shown) on the chassis side of the apparatus.

The pressing springs 25a and 25b are respectively contracted between both ends of the pressing rigid stay 22 and the spring receiving members 29a and 29b on the apparatus chassis side, so that a pressing force is applied to the pressing rigid stay 22. Let me. Thus, the sliding member 40 disposed on the lower surface of the film guide member 16
Is pressed against the upper surface of the pressure roller 30 with the fixing film 10 interposed therebetween to form a fixing nip portion N having a predetermined width.

The pressing roller 30 is driven to rotate in the counterclockwise direction indicated by the arrow by the driving means M. A rotational force acts on the fixing film by the frictional force between the pressing roller and the fixing film 10 due to the rotational drive of the pressing roller 30, and the fixing film 10 has an inner surface at the fixing nip portion N and a sliding member 40. The outer peripheral surfaces of the film guide members 16a and 16b are rotated in a clockwise direction indicated by an arrow at a peripheral speed substantially corresponding to the rotational speed of the pressure roller 30 while sliding on the lower surface of the film guide member.

Thus, the pressure roller 31 is driven to rotate,
Accordingly, the fixing film 10 rotates, and the excitation circuit 27
Is supplied to the exciting coil 18 to generate the electromagnetically induced heat of the fixing film 10 as described above.
In a state where the temperature rises to a predetermined temperature and is controlled,
The recording material P on which the unfixed toner image t is conveyed from the image forming unit (not shown) faces the image surface upward between the fixing film 10 and the pressure roller 30 in the fixing nip portion N, that is, the image is fixed. When the fixing nip portion N is introduced to face the film surface, the image surface of the fixing nip portion N closely contacts the outer surface of the fixing film 10, and the fixing nip portion N is conveyed together with the fixing film.

In the process in which the recording material P is nipped and conveyed through the fixing nip portion N together with the fixing film 10,
The unfixed toner image t on the recording material P is heated and fixed to the recording material P by being heated by the electromagnetic induction heating of the fixing film 10. When the recording material P passes through the fixing nip portion N, it is separated from the outer surface of the fixing film 10 and is discharged and conveyed.
After passing through the fixing nip, the heat-fixed toner image on the recording material is cooled and becomes a permanent fixed image.

The flange members 23a and 23b receive the ends of the fixing film 10 when the fixing film 10 rotates, and serve to regulate the shifting of the fixing film 10 along the length of the film guide. The flange members 23a and 23b may be configured to rotate following the fixing film 10.

In this embodiment, since a toner containing a low softening substance is used in the toner t, an oil applying mechanism for preventing offset is not provided in the fixing device, but a toner containing no low softening substance is used. In this case, an oil application mechanism may be provided. Also, when a toner containing a low softening substance is used, oil application or cooling separation may be performed.

(3) Fixing Film 10 FIG. 8 is a schematic diagram of the layer structure of the fixing film 10 in this embodiment. The fixing film 10 of this embodiment includes a heating layer 1 made of a metal film or the like as a base layer of the fixing film 10 as an electromagnetic induction heating element, an elastic layer 2 laminated on the outer surface thereof, and a release layer laminated on the outer surface. 3 is a composite structure. A primer layer (not shown) may be provided between each layer for adhesion between the heat generating layer 1 and the elastic layer 2 and adhesion between the elastic layer 2 and the release layer 3. In the fixing film 10, the heat generating layer 1 is on the inner side, and the release layer 3 is on the outer side.

As described above, when the alternating magnetic flux acts on the heat generating layer 1, an eddy current is generated in the heat generating layer 1, and the heat generating layer 1 generates heat. The heat heats the fixing film 10 via the elastic layer 2 and the release layer 3, and heats a recording material as a material to be passed through the fixing nip N to heat and fix the toner image. .

A. Heating Layer 1 The heating layer 1 is preferably made of a ferromagnetic metal such as nickel, iron, ferromagnetic SUS, and nickel-cobalt alloy. A non-magnetic metal may be used, but a metal such as nickel, iron, magnetic stainless steel, or a cobalt-nickel alloy, which has good magnetic flux absorption, is more preferable. It is preferable that the thickness is larger than the skin depth represented by the following formula and 200 μm or less.

The skin depth σ [m] is determined by the frequency f of the excitation circuit.
[Hz], magnetic permeability μ, and specific resistance ρ [Ωm] are expressed as σ = 503 × (ρ / fμ) ^1/2 .

This indicates the depth of absorption of electromagnetic waves used in electromagnetic induction. As shown in FIG. 7, the intensity of electromagnetic waves at a depth deeper than this is 1 / e or less, and conversely, Most energy is absorbed up to this depth.

The thickness of the heat generating layer 1 is preferably 1 to 100 μm.
m is good. If the thickness of the heat generating layer 1 is smaller than 1 μm, most of the electromagnetic energy cannot be absorbed, so that the efficiency is deteriorated. On the other hand, if the heating layer 1 has a thickness of more than 100 μm, the rigidity becomes too high, and the flexibility deteriorates, which is not practical for use as a heating rotator. Therefore, the thickness of the heat generating layer 1 is preferably 1 to 100 μm.

B. Elastic Layer 2 The elastic layer 2 is made of silicone rubber, fluorine rubber, fluorosilicone rubber, or the like, and has good heat resistance and good thermal conductivity. The thickness of the elastic layer 2 is preferably from 10 to 500 μm.
The elastic layer 2 has a thickness necessary to guarantee the quality of a fixed image.

If the thickness of the elastic layer 2 is less than 10 μm, the unevenness of the recording material P or the toner layer cannot be completely followed, and image gloss unevenness occurs. Also, if the elastic layer 2 is 100
If it is 0 μm or more, the thermal resistance of the elastic layer becomes large, and it is difficult to realize quick start. More preferably, the thickness of the elastic layer 2 is preferably 50 to 500 μm.

If the hardness of the elastic layer 2 is too high, the elasticity of the elastic layer 2 cannot follow the irregularities of the recording material P or the toner layer, resulting in uneven image gloss. Therefore, the hardness of the elastic layer 2 is preferably 60 ° (JIS-A) or less, more preferably 45 ° (JIS-A) or less. The thermal conductivity λ of the elastic layer 2 is preferably 0.25 to 0.84 [W / m · ° C.].

When the thermal conductivity λ is smaller than 0.25 [W / m · ° C.], the thermal resistance is large, and the temperature rise in the surface layer (release layer 3) of the fixing film becomes slow. When the thermal conductivity λ is larger than 0.84 [W / m · ° C.], the hardness becomes too high or the compression set becomes worse.

Therefore, the thermal conductivity λ is 0.25 to 0.84
[W / m · ° C.] is preferable. More preferably, 0.33-0.
63 [W / m · ° C.] is preferable.

When a color image is printed, a solid image is formed over a large area on the recording material P, especially for a photographic image. In this case, if the heating surface (the release layer 3) cannot follow the unevenness of the recording material P or the unevenness of the toner layer, uneven heating occurs, and gloss unevenness occurs in an image in a portion having a large amount of heat transfer and a portion having a small amount of heat transfer. The glossiness is high in a portion having a large amount of heat transfer, and low in a portion having a small amount of heat transfer.

C. Release Layer 3 The release layer 3 is made of a fluororesin (PFA, PTFE, FEP),
A material having good releasability and heat resistance, such as silicone resin, fluorosilicone rubber, fluorine rubber, and silicone rubber, can be selected. The thickness of the release layer 3 is 1 to 100 μm.
m is preferred. If the thickness of the release layer 3 is less than 1 μm, problems such as the formation of a portion having poor release properties due to coating unevenness of the coating film and insufficient durability occur. On the other hand, if the thickness of the release layer exceeds 100 μm, there is a problem that heat conduction is deteriorated. In particular, in the case of a resin-based release layer, the hardness becomes too high, and the effect of the elastic layer 2 is lost.

FIG. 10 shows the structure of another fixing film 10 in which a heat insulating layer 4 is provided on the inner side of the heat generating layer 1 (on the side opposite to the elastic layer 2 of the heat generating layer 1). As the heat insulating layer 4, a fluororesin (PFA resin, PTFE resin, FEP
Resins), polyimide resins, polyamide resins, polyamide-imide resins, PEEK resins, PES resins, and PPS resins.

The thickness of the heat insulating layer 4 is 10 to 10
00 μm is preferred. When the thickness of the heat insulating layer 4 is smaller than 10 μm, the heat insulating effect cannot be obtained, and the durability is insufficient. On the other hand, when the thickness exceeds 1000 μm, the distance between the magnetic core 17 and the exciting coil 18 and the heat generating layer 1 increases, and the magnetic flux cannot be sufficiently absorbed by the heat generating layer 1.

Since the heat insulating layer 4 can insulate heat generated in the heat generating layer 1 so as not to go to the inside of the fixing film, the heat supply efficiency to the recording material P is higher than in the case where the heat insulating layer 4 is not provided. Become. Therefore, power consumption can be suppressed.

D. FIG. 8A shows a sectional shape of the fixing film 10. FIG. 9A is a perspective view of the fixing film 10, and FIG.
FIG. 2B shows that the fixing film 10 is developed at a position indicated by a dotted line A, and film guide members 16a and 16
3B shows the inner surface side of the fixing film 10 in contact with b. Recess 41
Is a groove-shaped recess formed in the heat generating layer 1 which is the innermost layer of the fixing film 10 and holding a lubricant G having a width of 0.2 mm and a depth of 0.005 mm.
When it is set to ゜, it is arranged at an angle of 15 °. This angle θ
m is 5 ° ≦ | θm | ≦ 6 in consideration of the holding effect of the lubricant G.
0 ° or less is good. If it is less than 5 °, the effect of holding the lubricant G is high, but the edge of the concave portion is easily scratched, which causes an increase in torque. On the other hand, when the angle exceeds 60 °, the effect of retaining the lubricant G is reduced. The width of the recess 41 is preferably in the range of 0.1 to 1 mm with respect to the longitudinal direction of the fixing film 10.

In this example, the thickness of the heat generating layer 1 was set to 50 μm. It is preferable that the concave portion 41 has a depth of 0.005 mm or more and is formed in a range of 5 to 20% with respect to the thickness of the innermost layer of the fixing film 10. When the width is less than 0.1 mm and the depth is less than 0.005 mm with respect to the longitudinal direction, the effect of retaining the lubricant G is not sufficient, and the effect of reducing the torque cannot be sufficiently obtained.

When the width of the recess 41 exceeds 1 mm in the longitudinal direction of the fixing film 10, the width of the recess 41 becomes too large, and the edge of the recess 41 is easily caught, thereby causing an increase in torque. The recesses 41 may be formed at predetermined intervals along the longitudinal direction so that the total area of the recesses 41 is 10 to 60% of the area of the recess formation region. Recess 4
The pitch between the centers of 1 may be arbitrary.

In the present invention, as a method for calculating the area of the concave portion 41, the projected area at a position １ ／ of the depth of the concave portion 41 is defined as the area of the concave portion 41. As a comparative example, when the concave portion 41 continuous in the longitudinal direction was provided, the pressing force was concentrated linearly at the edge of the concave portion 41, causing an increase in torque.

By arranging the concave portion 41 obliquely as in this example, the pressing force applied to the edge portion of the concave portion 41 is dispersed, and the fixing film 10 and the sliding plate 40 are not increased without increasing the torque.
Can be reduced. Therefore, the adhesion between the fixing film and the sliding plate 40 can be reduced. For this reason, the torque at the time of starting rotation from a low temperature such as room temperature can be suppressed as compared with the configuration without the concave portion 41.

FIG. 8B shows an example of the connection between the flat portion of the fixing film 10 (directly, the flat portion of the heat generating layer 1) and the concave portion 41. As shown in FIG. 8C, it is more preferable that the flat portion of the fixing film 10 and the concave portion 41 are continuously connected by a curved surface. Fixing film 10 by connecting on a curved surface
It is possible to reduce the sliding frictional force at the contact portion with the sliding plate 40 and to prevent the edge of the concave portion 41 from damaging the sliding plate 40.

Regarding the effect of holding the lubricant G in the concave portion 41,
The sliding member (fixing film 10 or sliding plate 4)
When the fixing film 10 rotates without the concave portion 41 in 0), the lubricant G is swept out from between the fixing film 10 and the sliding plate 40 by the pressing force for forming the fixing nip portion. , And hardly remained on the sliding portion corresponding to the fixing nip portion N.

However, since the lubricant G is held in the concave portion 41 of the fixing film 10, the mutual sliding frictional force of the sliding portion corresponding to the fixing nip N can be reduced. Therefore, it is possible to prevent an increase in torque due to endurance, and it is possible to extend the life of the apparatus without causing a step-out of a motor for driving the driving roller or a problem such as fixing jam. The shape of the concave portion 41, the total area ratio of the concave portion, and the like are appropriately determined by the pressing force, the material of the sliding member of the fixing nip N, the material of the film guide 2a, and the like.

When the length of the fixing film 10 is L _F , the length of the recess 41 is L _B , and the length of the pressure roller 30 is L _R , L _F > L _B ≧ L _R It is better to satisfy.

Here, L _R corresponds to the longitudinal length of the sliding portion. In the case of L _F = L _B, the recess 41 the fixing film 10
, The shape of the end face of the fixing film 10 becomes uneven. On the end face of the fixing film 10, stress is likely to be concentrated on the boundary between the irregularities due to the deformation, and the possibility of causing a break is increased. When _LB < _LR , since the concave portion 41 of the fixing film 10 is shorter than the sliding portion, it is desired to supply the lubricant G to the entire sliding portion, so that the torque reducing effect is reduced.

As a confirmation of the effect of the present embodiment, the rotation starting torque at room temperature was measured for every 5000 A4 sheets using the fixing device 100 of the present embodiment. Fixing nip N is 196
N was applied, and the width of the fixing nip was about 7 mm.
As a comparative example (conventional example), the concave portion 41 was formed in the fixing film 10.
The rotation start torque when no was provided was measured.

In the conventional fixing film 10 in which the concave portion 41 is not provided, the initial rotation start torque (the torque on the pressure roller shaft as a driving roller) was 49 N · cm. When the rate of increase of the rotation starting torque increases and exceeds 100,000 sheets, 73.5 N · c
m or more, step-out of the drive roller or the like occurs.

On the other hand, when the concave portion 41 is provided as in this embodiment, the initial rotation starting torque is 44 N · cm, which is lower than that of the conventional case, and 49 N · even when 50,000 sheets are passed. cm, and even when 200,000 sheets have passed
3.7 Ncm or less could be maintained.

FIG. 10 shows the concave portion 41 when the heat insulating layer 4 is provided.
It is possible to adopt a configuration similar to the concave portion shown in FIG. 8, which is an example of the above. However, as shown in FIG. 11, a groove-shaped concave portion is provided in a cross shape. In this case, the lubricant G of the fixing film 10
Can be increased. Note that FIG.
(A) shows a cross section of the fixing film 10,
FIG. 10B shows one mode of connection between the flat portion of the fixing film 10 (directly, the flat portion of the heat generating layer 1) and the concave portion 41, and FIG. 10C shows the flat portion of the fixing film 10. And the concave portion 41 are continuously connected by a curved surface.

(Second Embodiment) In the present embodiment, as shown in FIG. 12, except for the shape of the concave portion provided in the fixing film 10 in the first embodiment, the second embodiment is different from the first embodiment. It has a similar configuration. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

FIG. 12 is an expanded view of the fixing film 10 at the position indicated by the dotted line A, similarly to FIG. 9, and shows the inner surface of the fixing film 10. The concave portion 42 has a diameter of 0.2 mm and a depth of 0.00 mm formed in the heat generating layer 11 which is the innermost layer of the fixing film 10.
It has a concave shape of 5 mm. The width of the recess 42 is preferably in the range of 0.1 to 1 mm with respect to the rotation direction of the fixing film 10.

In this example, the thickness of the heat generating layer 1 was set to 50 μm. It is preferable that the concave portion 42 has a depth of 0.005 mm or more and is formed in a range of 5 to 20% with respect to the thickness of the innermost layer of the fixing film 10. When the width is less than 0.1 mm and the depth is less than 0.005 mm with respect to the longitudinal direction, the effect of retaining the lubricant G is not sufficient, and the effect of reducing the torque cannot be sufficiently obtained. When the width of the recess 42 exceeds 1 mm with respect to the longitudinal direction of the fixing film 10, the width of the recess 42 becomes too large.
The edge of the head becomes easily caught, which causes an increase in torque.

It is preferable to form the recesses 42 at intervals set along the longitudinal direction so that the total area of the recesses 42 is 10 to 60% of the area of the recess formation region. The pitch between the centers of the concave portions 42 may be arbitrary, but it is preferable that the concave portions 42 are disposed so that the concave portions 42 always exist in the traveling direction of the fixing film 10.

The method of calculating the area of the concave portion 42 is as follows.
The projected area at a position １ ／ of the depth of the recess 42 is defined as the area of the recess. The arrangement of the concave portions 42 with respect to the longitudinal direction in the fixing nip portion N may be arranged such that the concave portions always exist within the fixing nip width.

For example, FIG. 13 is an enlarged view of the concave portion 42 on the inner surface of the fixing film, and can be arranged in a grid point shape as shown in FIG.

Further, as shown in FIG. 13B, the shape of the concave portion 42 can be made like a water droplet type concave portion 43. At this time, it is preferable that the arc-shaped side of the water droplet type is on the side of the traveling direction of the fixing film 10. Since the water droplet type recess 43 has a shape having the smallest sliding resistance in the traveling direction of the fixing film 10, the sliding resistance can be reduced. Was completed.

By arranging the concave portions 43 in a lattice pattern as in this example, the pressing force applied to the edge portions of the concave portions is dispersed, and the fixing film 10 and the sliding plate 40 are not increased without increasing the torque.
Can be reduced. Therefore, the adhesion between the fixing film 10 and the sliding plate 40 can be reduced. For this reason, the torque at the time of starting rotation from a low temperature such as room temperature can be suppressed lower than the configuration in which the concave portion 43 is not provided. The edge of the concave portion 43 is the first
The torque can be further reduced by connecting with a curve as in the embodiment.

(Third Embodiment) This embodiment is an example of a film heating type fixing device using a ceramic heater as a heating element. FIG. 14 shows an image heating apparatus 1 according to this embodiment.
It is a cross-sectional model diagram of 00. Reference numeral 16c denotes a heat-resistant and heat-insulating film guide having a substantially semicircular cross section in cross section, and 12 denotes a ceramic heater as a heating element.
c is fitted and fixedly supported in a substantially central portion of the lower surface along the longitudinal direction of the guide.

Reference numeral 11 denotes a cylindrical or endless heat-resistant fixing film. The fixing film 11 is loosely fitted to the film guide 16c. Reference numeral 22 denotes a pressurizing rigid stay inserted inside the film guide 16c. Reference numeral 30 denotes a pressing member, which is an elastic pressing roller, which is provided with an elastic layer 30b made of silicone rubber or the like on a core metal 30a to reduce the hardness. Both ends of the core metal 30a are not shown in the drawing. The bearings are rotatably held between the front and rear chassis side plates. In order to improve the surface properties, a fluororesin layer such as PTFE, PFA, FEP may be further provided on the outer periphery.

The pressurizing means for forming the fixing nip N and the means for holding the end of the fixing film have the same construction as in the first embodiment, and a description thereof will be omitted.

The pressure roller 30 is driven to rotate in the counterclockwise direction indicated by the arrow by the driving means M. A rotational force acts on the fixing film 11 by a frictional force between the pressing roller 30 and the outer surface of the fixing film 11 due to the rotational driving of the pressing roller 30, so that the inner surface of the fixing film 11 becomes a ceramic heater in the fixing nip portion N. The outer peripheral surface of the film guide 16c is rotated in a clockwise direction indicated by an arrow at a peripheral speed substantially corresponding to the rotational peripheral speed of the pressure roller 30 while sliding in close contact with the lower surface of the pressure roller 12 (pressure roller drive system).

In order to reduce the mutual sliding friction force between the lower surface of the ceramic heater 12 and the inner surface of the fixing film 11 in the fixing nip N, a sliding plate 40 is provided on the lower surface of the ceramic heater 12 in the fixing nip N. Then, a lubricant G such as heat-resistant grease is interposed between the fixing film 11 and the inner surface thereof.

The rotation of the pressure roller 30 is started based on the print start signal, and the heating of the ceramic heater 12 is started. When the rotation peripheral speed of the fixing film 11 is stabilized by the rotation of the pressure roller 30 and the temperature of the ceramic heater 12 rises to a predetermined value, the fixing film 11 in the fixing nip N and the pressure roller 3
0, the recording material P carrying the toner image t as the material to be heated is introduced with the toner image carrying surface side being the fixing film 11 side, so that the recording material P becomes the fixing nip portion N
At the time, the fixing film 11 is in close contact with the lower surface of the ceramic heater 12 via the fixing film 11, and moves and passes through the fixing nip portion N together with the fixing film. In the moving passage process, the heat of the ceramic heater 12 is applied to the recording material P via the fixing film 11, and the toner image t is heated and fixed on the surface of the recording material P. Recording material P that has passed through fixing nip portion N
Is transported after being separated from the surface of the fixing film 11.

The fixing film 11 has a film thickness of 100 μm or less, preferably 50 μm or less and preferably 20 μm or more, and is made of a single layer of heat-resistant PTFE, PFA, FEP, or polyimide, in order to reduce the heat capacity and improve the quick start property. Polyimide amide, PEEK, PES, P
A composite layer film in which the outer peripheral surface of PS or the like is coated with PTFE, PFA, FEP, or the like can be used. In this example, a polyimide film having a diameter of 25 mm coated with PTFE on the outer peripheral surface was used.

The ceramic heater 12 as a heating element is
It is a low-heat-capacity horizontally long linear heating element whose longitudinal direction is the direction perpendicular to the direction of movement of the fixing film 11 and the recording material P. The heater substrate 12a is made of aluminum nitride or the like. A heat generating layer 12b provided along its length, for example, a heat generating layer 12b provided by applying an electric resistance material such as Ag / Pd (silver / palladium) to a thickness of about 10 μm and a width of 1 to 5 mm by screen printing or the like; It basically has a protective layer 12c made of glass, fluororesin or the like provided thereon.

Heating layer 12b of the ceramic heater 12
The heating layer 12b generates heat and the temperature of the ceramic heater 12 rises rapidly due to the current flowing between both ends of the heating layer. The heater temperature is detected by a temperature sensor (not shown), and a heating circuit 1 is controlled by a control circuit (not shown) so that the heater temperature is maintained at a predetermined temperature.
2b is controlled so that the ceramic heater 12
Is temperature controlled.

The ceramic heater 12 is fixedly supported by fitting the protection layer 12c upward into a groove formed substantially along the center of the lower surface of the film guide 16c along the length of the guide. In the fixing nip portion N in contact with the fixing film 11, the sliding plate 4 of the ceramic heater 12 is used.
The surface 0 and the inner surface of the fixing film 11 slide in contact with each other.
In this embodiment, even in a heating mode different from that of the first or second embodiment, it is possible to reduce the torque at the time of starting rotation and at the time of steady rotation.

A ferromagnetic metal plate such as an iron plate is provided in place of the ceramic heater, and the ferromagnetic metal plate is heated by electromagnetic induction used in the first to third embodiments to be used as a heater. You can also.

(Other Embodiments) 1) The fixing film 10 having an electromagnetic induction heating property may have a configuration in which the elastic layer 2 is omitted in the case of heat fixing such as a monochrome or one-pass multicolor image. it can.
The heat generating layer 1 may be formed by mixing a metal filler into a resin. The heating layer may be a single layer member.

2) The configuration of the image heating device 100 as a heating device is not limited to the pressure roller driving system of the embodiment. For example, as shown in FIG. 15, the film guide 16, the driving roller 31, the tension roller 32
The fixing film 10 in the form of an endless film having electromagnetic induction and heat is suspended and stretched, and the fixing film 10 is pressed between the lower surface of the film guide 16 and the pressing roller 30 as a pressing member. Thus, the fixing nip portion N may be formed, and the fixing film 10 may be driven to rotate by the driving roller 31. In this case, the pressure roller 30 is a driven rotation roller.

3) The pressing member is not limited to the pressing roller 30,
Other types of members, such as a rotating film type, can also be used. In order to supply thermal energy to the recording material also from the pressing member side, a heating device such as electromagnetic induction heating may be provided on the pressing member side to heat and control the temperature to a predetermined temperature. it can.

4) The heating apparatus of the present invention is not limited to the image heating and fixing apparatus of the embodiment, but may be an image heating apparatus that heats a recording material holding an image to improve the surface properties such as gloss, Heating equipment, other means for heating the recording material widely, such as a heating and drying device for the recording material, and a heating laminating device.
Can be used as a device.

5) In forming the concave portion, a convex portion corresponding to the concave portion can be formed on the matrix at the time of forming the concave portion forming layer. For example, in the case of nickel, a projection can be formed on a plating mold. Also, when a concave portion is provided in the heat insulating layer, it can be formed by dipping, spray coating, or the like on a matrix provided with a convex portion. In addition, the concave portion can be formed by a method such as embossing, etching, and pressing.

[0105]

As described above, according to the present invention,
By arranging the concave portion for holding the lubricant on the inner surface of the fixing film in contact with the support member, the adhesive force between the fixing film and the sliding member can be reduced, and the rotation starting torque at a low temperature such as room temperature can be reduced. It can be kept low throughout the durability life. Further, a heating device that can reduce sliding friction resistance in a nip portion between a fixing film and a member holding the fixing film, can reduce driving torque, and can prolong the life of the heating device can be provided. There is an effect that can be obtained.

Further, by applying this heating device as an image heating and fixing device, there is an effect that an image forming apparatus capable of forming a high quality fixed image can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus.

FIG. 2 is a cross-sectional model view of a main part of the fixing device according to the first embodiment.

FIG. 3 is a front view of the main part of the model.

Fig. 4 Longitudinal model diagram of main parts

FIG. 5 is a model diagram of a magnetic field generating means.

FIG. 6 is a diagram showing a relationship between a magnetic field generating means and a heat generation amount Q.

FIG. 7 is a schematic diagram of a layer structure of a fixing film.

FIG. 8 is a graph showing a relationship between a heating layer depth and an electromagnetic wave intensity.

FIG. 9 is a perspective view and a development view of a fixing film.

FIG. 10 is a schematic diagram of another layer configuration of the fixing film.

FIG. 11 is a development view of a fixing film.

FIG. 12 is a development view of a fixing film according to the second embodiment.

FIG. 13 is an enlarged view of a concave portion formed in the fixing film.

FIG. 14 is a schematic diagram of a configuration of a heating device according to a third embodiment.

FIG. 15 is a schematic diagram of another example of a heating device using an electromagnetic induction heating method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Heat generation layer 2 Elastic layer 3 Release layer 4 Heat insulation layer 10 Fixing film 16 Film guide 17 Magnetic core 18 Excitation coil 23a / 23b Flange member for regulating and holding end of fixing film 26 Temperature detecting element (thermistor) 27 Safety temperature Detecting element 30 Pressure roller as pressure member 31 Drive roller 32 Tension roller 40 Sliding plate (sliding member) 41 Groove-shaped recess 42 Recess 43 Water-drop recess

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2H033 AA14 AA23 AA41 BA11 BA12 BA25 BA26 BA27 BA31 BA32 BE03 BE06 3K059 AA08 AB00 AB04 AB19 AB20 AB23 AB28 AC10 AC33 AC73 AD03 AD07 AD28 CD44 CD52 CD66 CD73 CD77

Claims (14)

[Claims] A rotating member, a pressing member for pressing the rotating member, and a supporting member for supporting the rotating member, wherein the supporting member is brought into contact with the rotating member and the pressing member. A portion corresponding to the formed contact portion has a sliding portion with the inner surface of the rotating body, and the material to be heated is nipped and conveyed by the contact portion formed by the contact between the rotating body and the pressing member. A heating device for pressurizing and heating a material to be heated, wherein a recess is provided on the inner surface of the rotating body. 2. The heating device according to claim 1, wherein a recess is provided in a groove shape on the inner surface of the rotating body. 3. The heating device according to claim 1, wherein a plurality of independent concave portions are provided on the inner surface of the rotating body. 4. When the angle between the groove-shaped concave portion and the longitudinal direction of the rotating body is θm and the longitudinal direction of the rotating body is 0 °, 5 ° ≦ | θm | ≦ 60 ° is satisfied. The heating device according to claim 1, wherein: 5. When the length of the rotating body is L _F , the length of the recess is L _B , and the length of the pressure member is L _R , L _F > L _B ≧ The heating device according to any one of claims 1 to 4, wherein _LR is satisfied. 6. The longitudinal length L _B of the recess of the rotary body surface is formed, heating of claim 5, the area of the recess, characterized in that formed so as to occupy 10% to 60% apparatus. 7. The recess has a width of 0.1 to 1 mm, a depth of 0.005 mm or more, and a length less than the width of the sliding portion with respect to the rotation direction of the rotating body. Claim 1
7. The heating device according to any one of claims 1 to 6. 8. The rotator has a plurality of layers made of different materials, and the recess is formed in a range of 5% to 20% of the thickness of the innermost layer. The heating device according to any one of the above. 9. The heating device according to claim 1, wherein in the configuration in which a lubricant is interposed between the rotating body and the sliding portion, the recess holds the lubricant. apparatus. 10. The heating device according to claim 1, wherein the rotating body is an endless film having flexibility. 11. The apparatus according to claim 1, wherein said rotator is made of an electromagnetic induction heating member, and has a magnetic field generating means for applying a magnetic field to said electromagnetic induction heating member to generate heat.
0. The heating device according to any one of the above. 12. The rotating body is made of a heat-resistant film,
The heating device according to claim 1, wherein a heating body heats the material to be heated via the heat-resistant film. 13. The apparatus according to claim 1, wherein the material to be heated is a recording material on which an unfixed image is formed and carried, and the apparatus is a heat fixing device for heating and fixing the unfixed image on the recording material. 13. The heating device according to any one of 12 above. 14. An image forming means for forming and carrying an unfixed image on a recording material, and a fixing means for fixing an unfixed image formed and carried on the recording material, wherein the fixing means is provided. An image forming apparatus, which is the heating apparatus according to any one of the above.