JPH06194975A - Heating device - Google Patents

Abstract

PURPOSE:To prevent the wear of a film caused by a step part formed by a heat generating body for a heating body in a body in a heating device for an image forming device, etc. CONSTITUTION:As to the heating device provided with the heating body 20 which is arranged on one face side of the film 1 and an image carrier 4 which is brought into tight contact with the other face side of the film 1 and for giving heat energy to the image carrier 4 through the film 1, the heating body 20 is constituted of a ceramic substrate 21d, the heat generating layer 21e and a protective layer 21g arranged on the substrate 21d, and the width of the heat generating layer 21e is made larger than the width of a nip formed between a pressure roll for pressing the image carrier 4 against the heating body 20 and the film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating device of the type which applies heat energy to a recording material through a heat resistant film.

This device is an electrophotographic copying machine, printer,
An image heating and fixing device in an image forming apparatus such as a fax, that is, a recording material (electrofax sheet. A recording material carrying an unfixed toner image corresponding to the target image information formed on the surface of an electrostatic recording sheet, a transfer material sheet, a printing paper, etc. by a direct method or an indirect (transfer) method. It can be used as an image fixing device that performs heat fixing processing as a permanently fixed image on the surface.

[0003]

2. Description of the Related Art Next, conventional technology will be described.

<Conventional Example 1> Conventionally, a fixing device used in this type of device includes a heating roller which is maintained at a predetermined temperature and a pressure roller which has an elastic layer and is in pressure contact with the heating roller. Therefore, a roller fixing method is often used in which a recording material on which an unfixed toner image is formed is nipped and conveyed and heated.

A belt fixing system as disclosed in US Pat. No. 3,578,797 is also known.

Further, in recent years, as disclosed in Japanese Patent Laid-Open No. 1-263680, a fixing film, a running driving means for the fixing film, and the fixing film are fixedly supported on one side of the fixing film. A heating member and a pressing member arranged on the other surface side to bring the surface of the recording material on the unfixed toner image bearing side of the heating member into close contact with the heating member via the fixing film. An unfixed toner image is introduced by introducing the recording material between the fixing film and the pressing member, which are driven to run in the same direction at the same speed as the conveying speed of the recording material carrying the unfixed toner image being conveyed. A toner image heat fixing unit (hereinafter referred to as a surf system) that heats and fixes the recording material surface has also been proposed.

<Conventional Example 2> Conventionally, for example, a recording material heating device for heating and fixing an image has a heating roller maintained at a predetermined temperature and an elastic layer, and is pressed against the heating roller. A heating roller system is widely used in which a recording material is heated while being nipped and conveyed by a pressure roller. Further, various systems and configurations such as a flash heating system, an oven heating system, and a hot plate heating system are known and put into practical use.

A belt heating system is also known, as disclosed in US Pat. No. 3,578,797. This is a state in which the toner image is brought into contact with the heating body web and is heated to its melting point to be melted, and after melting, the toner is cooled to have a relatively high viscosity and the tendency of the toner to adhere to the heating body web is weakened. It is a method of fixing without causing offset by going through the process of peeling from the heating element web.

Recently, a fixedly supported heating element (thermal heater, hereinafter referred to as a heater), a heat resistant film (fixing film) conveyed while being pressed against the heater,
An unfixed image formed and carried on the surface of the recording material is formed on the surface of the recording material by applying heat of the heater to the recording material through the film. A fixing device (film heating system) having a system and configuration for heating and fixing to a sheet has been devised (for example, Japanese Patent Laid-Open No. 63-
313182).

A gloss forming device is disclosed in Japanese Patent Laid-Open No. 64
-35452, JP-A-1-161344-161347.
As disclosed in U.S. Pat. No. 5,242,096, a device for forming a smooth image by belt fixing is known.

[0011]

However, the thermal roll fixing system and the belt fixing system as in the above-mentioned conventional example 1 have the following problems.

Thermal roll fixing system It takes a long time to rise to a predetermined temperature,
During that time, the image forming operation is prohibited. That is, there is a so-called wait time.

A large amount of electric power is required because a heat capacity is required.

Since the roller temperature of the rotating roller is high, a heat resistant special bearing is required.

[0015] The roller is configured to be directly touched,
Dangerous or need protective material. Due to the constant temperature and curvature of the roller, the recording material is easily wrapped around the roller and jamming of the recording material is easily seen.

Belt fixing method This method also has the problems of the above-mentioned heat roller fixing method, the same wait time as in the above, and large power consumption.

Surf system Due to long-term durability of the heater surface and the film surface, the film surface may be worn, and abrasion powder may adhere to the step difference of about 8 μ in the heating portion of the heater, which further promotes the wear of the film.

As shown in FIG. 4, this step has a step difference of about 10 μ in thickness of the heating resistor because the heating resistor 21e is screen-printed on the alumina substrate 21d, and the overcoat layer 21g is applied. This is caused because a step difference of about 8 μ remains after that.

As in the conventional example shown in FIG. 3, since the width of the heating element is narrower than the nip width, a step portion of the heater heating element occurs and the film is worn at the edge portion C and is worn on this portion. This is because the powder adheres and a vicious cycle occurs in which the abrasion of the film is promoted. Finally, a gap is generated between the heater heating surface and the film, which leads to occurrence of linear fixing failure.

For this reason, conventionally, the pressure applied to the heater of the pressure roll could not be increased to 350 g / cm or more, and it was difficult to cope with the high speed. Further, the nip width is also narrowed, and in order for the appropriate pressure to be applied to the area of the heating element, it is necessary to increase the parallel accuracy of the heating element and the pressure roll in the longitudinal direction, which increases the cost of parts. .

However, the conventional example 2 has the following drawbacks.

JP-A-64-35452 1. You cannot form a glossy, uneven image.

A mono-color image is easier to see and is more beautiful without gloss.

○ Overwriting with a pencil etc. is not possible.

2. Warm-up time is long. Large power consumption Large temperature rise in machine JP-A-63-313182 1. "Glossy image" is not possible.

Generally, a full-color image is more glossy. US Pat. No. 3,578,797 1. Always glossy, but only smooth images can be formed,
Overwriting with a pencil etc. is not possible.

2. Warm-up time is long, power consumption is large, and temperature rise inside the machine is large.

The present invention solves the above problems,
An object is to provide a heating device that operates well.

[0029]

[Means for Solving the Problems] In order to achieve the above-mentioned objects, the means for solving the present invention are as described in the claims, and the operation thereof is as follows.

According to the first aspect of the invention, the problems of the surf type heating device are improved, and the endless film is rotatably moved in contact with a fixedly supported heating element in a facing manner. In a device that heats and fixes a visible image by a pressing member that brings the recording material into close contact with the heating element, the width of the heating element of the heating element in the film running direction is
By making it larger than the nip width between the pressing member and the endless film, abrasion of the film with the heating zone is reduced and the amount of the abrasion powder adhered to the surface of the heating body is reduced.

According to the second aspect of the present invention, according to the present invention, in the SURF fixing, the pressure contact surface direction between the heating member and the pressure member and the film running direction downstream of the pressure contact portion are formed. By providing the means for changing the angle α, it is possible to change the surface property and glossiness of the fixed image.

Here, the angle is defined as a positive direction when the film feeding direction is on the heating body side and a negative direction when it is on the pressure roller side with respect to the direction of the pressure contact surface on the downstream side of the pressure contact portion.

[0033]

EXAMPLE An example according to claim 1 will be described below with reference to FIGS.

<Embodiment 1> FIGS. 1 and 2 show an embodiment of the present invention.

Reference numeral 1 denotes an endless belt-shaped fixing film, which includes a left driving roller 2, a right driven roller 3 and
A low heat capacity linear heating element 20 as a heating element disposed below the driving roller 2 and the driven roller 3 is suspended and stretched between the three members 2, 3 and 20 parallel to each other.

The driven roller 3 also serves as a tension roller for the endless belt-shaped fixing film 1, and the fixing film 1 is rotated at a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 2, that is, image formation. The transfer material sheet P having the unfixed toner image Ta conveyed from the side thereof on its upper surface is rotationally driven at the same peripheral speed as the conveyance speed without wrinkles, meandering, or speed delay.

Reference numeral 4 denotes a pressure roller as a pressure member having a rubber elastic layer with good releasability such as silicon rubber, which narrows the film portion on the descending side of the endless belt-shaped fixing film 1 and heats it. The lower surface of the body 20 is pressed against the lower surface of the body 20 by a biasing means (not shown) with a total pressure of 4 to 7 kg, and rotates counterclockwise in the forward direction of the conveyance direction of the transfer material sheet P.

Since the endless belt-shaped fixing film 1 which is rotationally driven is repeatedly used for heat fixing of the toner image, it is excellent in heat resistance, releasability and durability, and generally 10
A thin wall having a thickness of 0 μm or less, preferably 50 μm or less is used. For example, polyimide, polyetherimide, PEA
A single layer film of a heat-resistant resin such as (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin) or a composite layer film, for example, a 20 μm thick film, is electrically conductive to PTFE (tetrafluoroethylene resin) on at least the image contact surface side. For example, a release coating layer having a material added thereto is applied to a thickness of 10 μm.

The low heat capacity heating element 20 as a heating element of this example has a structure as shown in the cross-sectional model view of FIG.

That is, 21a is a supporting member for maintaining the strength of the whole, and is a fixing film transverse direction (fixing film 1
Is a high-rigidity, heat-resistant, low-thermal-conductivity member whose longitudinal direction is a direction perpendicular to the traveling direction of, for example, a horizontally long rectangular member made of PPS / polyimide / Bakelite. 21d is the support member 21
It is a substrate fitted and inserted into a laterally elongated slot 21b provided along the longitudinal direction on the lower surface of a to prevent it from being detached. This example is a ceramic substrate of 240 mm in length, 10 mm in width, and 1.0 mm in thickness, such as alumina, which has good thermal conductivity.

Reference numeral 21e designates the rear surface of the substrate (the surface which comes into pressure contact with the pressure roller 4 through the fixing film of the substrate 21d (the front surface of the substrate)).
It is a linear or strip-shaped low heat capacity heating element formed along the longitudinal direction in a substantially central portion of the surface (opposite side to). In this example, nichrome / tungsten / silver-palladium (Ag / Pd) / ruthenium oxide (RuO ₂ ) / Ta ₂ N or a resistance material (current-carrying heating element) containing them as a main component has a width of 1.0 m.
It is formed by coating (screen printing) with a thickness of 20 μm. A surface heating element such as a ceramic heater can also be used.

Reference numeral 21f designates a temperature detecting member provided on a substantially central surface portion of the substrate surface (a surface portion where the substrate and the pressure roller are in pressure contact with each other via the fixing film). In the present example, a Pt film as a low heat capacity resistance temperature detector is formed along the length of the surface portion of the substrate surface in a linear or strip shape with a width of 200 μm and a thickness of 10 μm by screen printing. A temperature detecting body such as a bead thermistor having a low heat capacity may be embedded in the surface portion of the substrate surface, or may be bonded to the substrate by using a highly heat-conductive adhesive.

Reference numeral 21g denotes a protective and coating layer made of a wear-resistant material such as glass or ceramic, which is thinly applied to a thickness of, for example, about 10 μm on the surface of the substrate including the temperature detector 21f.

A sensor (not shown) detects the front end of the transfer material sheet P carrying the unfixed toner image Ta on the upper surface, which is conveyed by the image forming start signal to the fixing device by the image forming operation signal. Then, the rotation (or running) of the fixing film 1 is started, the transfer material sheet P is guided by the guide, and the fixing sheet 1 and the pressure roller 4 at the pressure contact portion N between the heating body 20 and the pressure roller 4 are guided. And the surface of the unfixed toner image Ta comes into close contact with the lower surface of the fixing film 1 in the surface movement state at the same speed as the conveyance speed of the sheet P in the same direction as that of the sheet P and the surface shifts or wrinkles. Without passing through the fixing film 1, the fixing film 1 passes through the fixing nip portion while receiving the nip pressure between the heating body 20 and the pressure roller 4, and heat fixing is performed.

Further, the energization of the heating element 21e of the heating element 20 is controlled, the heat generated by the heating element 21e is conducted to the surface of the substrate, the temperature of the substrate surface is raised, and the temperature is detected by the temperature detecting element 21f and fed back to the energization control circuit. The heating element 21e
The temperature of the fixing nip portion is controlled to be maintained at a predetermined fixing temperature by controlling the energization of the fixing nip portion.

In this example, when the total pressure of the pressure roll was set to 8 kg, the nip was 2.5 mm with respect to the pressure roll of φ20 at 50 ° (Asker C).

Here, the width of the heating element (thickness 10 μm) is set to 5
When the thickness was set to mm, the nip width was set in the heating element region over the entire longitudinal direction, abrasion powder generated by long-term durability driving was significantly reduced, and the adhesion phenomenon of the abrasion powder to the heating element surface did not occur.

When the width of the heating element is h and the nip width is H,
At least h ≧ H, preferably h ≧ (H + 0.5)
(Unit is mm).

<Second Embodiment> FIG. 4 shows a second embodiment.
In this embodiment, the width of the heating element is widened to the upstream side of the paper. In this case, since the temperature of the film rises to a predetermined temperature immediately before the nip, it is possible to further widen the fixing latitude.

<Embodiment 3> The apparatus of this embodiment is a reciprocating type / rotating drum type / transfer type electrophotographic copying apparatus.

(1) Overall schematic configuration of the apparatus (FIG. 6) In FIG. 6, 100 is a machine casing of the apparatus, 101 is a reciprocating member made of a transparent plate member such as a glass plate disposed on an upper plate 100a of the machine casing. It is a moving document placing table, and is a machine casing upper surface plate 100a.
The upper part is driven to reciprocate to the right a and the left a'in the drawing at a predetermined speed. Reference numeral G denotes a document, which is set by placing the image surface side to be copied face down on the upper surface of the document mounting table 101 in accordance with a predetermined mounting standard, and pressing the document pressure plate 101a on the document pressing plate 101a. .

Reference numeral 100b denotes a slit opening serving as a document illuminating section which is opened on the surface of the upper surface plate 100a of the machine casing with a direction perpendicular to the reciprocating direction of the document placing table 101 (direction perpendicular to the paper surface) as a longitudinal direction. The downward image surface of the document G placed and set on the document placing table 101 is the right side a of the document placing table 101.
The light L of the lamp 107 passes through the position of the slit opening 100b sequentially from the right side to the left side in the forward movement process to the slit opening 100b,
It is received through the transparent original placing table 101 and illuminated and scanned. The light reflected from the document surface of the illumination scanning light is image-wise exposed on the surface of the photosensitive drum 103 by the short-focus small-diameter image-forming element array 102.

The photosensitive drum 103 is coated with a photosensitive layer such as a zinc oxide photosensitive layer or an organic semiconductor photosensitive layer, and is rotated in a clockwise direction indicated by an arrow b at a predetermined peripheral speed around the central support shaft 103a. In the rotating process, the charging device 104 uniformly charges the positive or negative polarity, and the uniformly charged surface is subjected to the image formation exposure (slit exposure) of the original image, so that the surface of the photosensitive drum 103 is formed. An electrostatic latent image corresponding to the image-exposed original image is sequentially formed.

This electrostatic latent image is sequentially visualized by a developing device 105 with toner made of resin or the like which is softened and melted by heating, and the toner image as the visualized image is provided with a transfer discharge device 108 as a transfer portion. It moves to the part.

Reference numeral S denotes a cassette in which transfer material sheets P as recording materials are stacked and accommodated. The sheets in the cassette are fed and fed one by one by the rotation of the feeding roller 106, and then the drum 103 by the registration roller 109. When the leading edge of the upper toner image forming portion reaches the portion of the transfer discharger 108, the leading edge of the transfer material sheet P also reaches the position between the transfer discharger 108 and the photosensitive drum 103, so that they coincide with each other. It is then delivered synchronously. Then, the transfer discharger 108 sequentially transfers the toner images on the photosensitive drum 103 side to the surface of the fed sheet.

The sheet which has received the toner image transfer at the transfer portion is sequentially separated from the surface of the photosensitive drum 103 by a separating means (not shown), and is fixed by a conveying guide 110 to a fixing device 11 described later.
The unfixed toner image carried to the sheet 1 is subjected to the heat fixing process, and is discharged onto the discharge tray 112 outside the machine as an image formed product (copy).

On the other hand, the photosensitive drum 10 after the toner image transfer
The third surface is repeatedly used for image formation after the cleaning device 113 removes adhered contaminants such as transfer residual toner.

(2) The fixing device 111 (FIGS. 6 and 7) 124 is an endless belt-shaped fixing film, and has a left driving roller 125, a right driven roller 126, and
A low heat capacity linear heating element 120 as a heating element disposed below the driving roller 125 and the driven roller 126 is suspended and stretched between the four members 125, 126, 127 and 120 parallel to each other. The fixing film 124 will be described in detail later in item (4).

Here, a lever L is attached to the driving roller 125, and one end of the lever L projects outside the main body, and the one end is moved up and down, whereby the position of the driving roller can be arranged at 125a or 125b. it can. That is, in this fixing device, the fixing film feeding angle with respect to the pressure contact surface direction n formed by the heating body 121 and the pressure roller 128 in the pressure contact portion N can be switched to α or α ′.

The fixing operation and its effect when the feeding direction is changed in this way will be described later.

The driven roller 126 also serves as a tension roller for the endless belt-shaped fixing film 124, and the fixing film 124 is rotated at a predetermined peripheral speed in the clockwise direction with the clockwise rotation of the driving roller 125, that is, image formation. The unfixed toner image T conveyed from the side of the unit 108
It is rotationally driven at the same peripheral speed as the conveyance speed of the transfer material sheet P carrying a on its upper surface without wrinkles, meandering, or speed delay. The drive roller 25 is a film 24 made of silicon rubber or the like.
On the other hand, the driven roller 26 is a metal roller coated with a heat resistant material having a high friction coefficient, and the driven roller 26 is, for example, a metal roller having a lower friction coefficient with respect to the film than the driving roller.

Reference numeral 128 denotes a pressure roller having a rubber elastic layer having a good releasability such as silicon rubber as a pressure member, and the lower end film portion of the endless belt-shaped fixing film 124 is sandwiched between the heating rollers. The lower surface of the body 120 is pressed against the lower surface of the body 120 by a biasing means (not shown) with a total pressure of 4 to 7 kg, and rotates counterclockwise in the forward direction of the conveyance direction of the transfer material sheet P.

Low heat capacity linear heating element 120 as a heating element
In the present example, a heater support 127 having laterally long rigidity, high heat resistance, and heat insulation with the longitudinal direction in the transverse direction of the fixing film (direction perpendicular to the running direction of the fixing film 125),
A heater substrate 121 having a heating element 122, a temperature measuring element 123, etc. integrally attached and held on the lower surface side of the support along the lower surface length is provided.

The heater support 127 heat-insulates and supports the heating body 120 with respect to the fixing device 111 and the entire copying machine. For example, PPS (polyphenylene sulfide), P
AI (polyamide imide), PI (polyimide), PE
It can be made of high heat resistant resin such as EK (polyether ether ketone) or liquid crystal polymer, or a composite material of these resins and ceramics, metal, glass or the like.

The heater substrate 121 has a thickness of 1.0 as an example.
mm, width 10 mm, length 240 mm alumina substrate. The heating element 122 is, for example, Ag / Pd (silver-palladium) along the length in the substantially central portion of the lower surface of the substrate 121.
An electric resistance material such as the above is applied by screen printing or the like to a thickness of about 10 μm and a width of 1 to 3 mm, and a heat-resistant glass 121a is coated thereon for about 10 μm as a surface protective layer. The surface roughness of the heat-resistant glass is 0.8 in terms of ten-point average roughness R _Z (μm).
μm, but this value is preferably 0.3 ≦ R _Z ≦ 3. As an example of the temperature measuring element 123, a heat-resistant lubricant is applied in advance to the surface of the surface protective layer 121a of the heating element in the substantially central portion of the upper surface of the substrate 121 (the surface opposite to the surface on which the heating element 122 is provided). I am doing it.

As a temperature measuring element which is a resistance temperature measuring element having a low heat capacity such as a Pt film provided by coating by screen printing or the like, it may be arranged so as to be in contact with the substrate 121 such as a thermistor having a low heat capacity. Good.

In the case of this example, electricity is applied to the linear or strip-shaped heating element 122 from both ends in the longitudinal direction, and the heating element 122 is caused to generate heat over substantially the entire length. Power is AC10
It is 0 V, and the energization power is controlled by controlling the energizing phase angle by an energization control circuit (not shown) including a triac according to the detected temperature of the temperature detecting element 123. (3) Fixing Execution Operation The transfer material sheet P carrying the unfixed toner image Ta on the upper surface, which is conveyed from the transfer portion 108 to the fixing device 111 by the image forming start signal of the apparatus and guided to the guide 129, is guided. Heated body 120 and pressure roller 128
The fixing film 124 and the pressure roller 128 at the pressure contact portion N with
And the unfixed toner image surface is rotated in the same direction at the same speed as the conveyance speed of the sheet P.
The heating element 12 is adhered to the lower surface of the heating element 24 in an overlapping state with the fixing film 124 without causing surface deviation or wrinkling.
0 and the pressure roller 128 pass through the mutual pressure contact portion N while receiving a clamping pressure.

Since the heating element 120 is electrically heated at a predetermined timing in response to the image formation start signal, the toner image Ta is heated at the press contact portion N to be softened and the fused image Tb is obtained.
Becomes

The fixing operation when the drive roller 125 is at the position 125a and when it is at the position 125b will be described below.

(A) When the position of the driving roller is 125a: The transfer material P, after passing through the pressure contact portion N, is about to be sent out in the pressure contact surface direction n, so that the pressure roller 1 has an angle of about 10 °.
Film 124 sent to the 28 side (α '=-10 °)
While the transfer material P is in close contact with the separation portion 151 (N to 151
Up to about 20 mm) and is separated from the film 124 at 151 parts by the curvature of the roller 125a (radius about 5 mm). The separated transfer material P is ejected by the paper ejection guide 130.
Then, the paper is discharged to the paper discharge tray 112.

In the above process, the toner image Tb heated and melted at the pressure contact portion N is cooled while being in close contact with the film 124 until it reaches the separating portion 151, and solidifies or becomes highly viscous. Is a smooth surface that follows the surface of the smooth fixing film 124.

Although the present embodiment has been described with respect to a mono-color image forming apparatus, a full-color image or the like having a gloss can form a beautiful image like a photograph, so that it is effective to fix the image in the above process. .

(B) When the position of the driving roller is 125b: After the fixing film 124 has passed the pressure contact portion N,
In the portion 152 having a large curvature of 7 (radius of curvature of about 5 mm), the strike direction turns to a steep angle (α = 45 °). Therefore, the transfer material P conveyed through the pressure contact portion N while being overlapped with the fixing film 124 is curvature-separated from the fixing film 124 at the edge portion 152, is guided to the paper ejection guide 130, and is ejected to the paper ejection tray 112. Will be done.

In this way, when the film 124 is separated from the transfer material P immediately after the heating and melting process at the pressure contact portion N, the toner image is generally in a molten state and the toner image surface generally has fine irregularities and is cooled. The toner image after solidification becomes an image with little gloss.

In general, a monochromatic image or an image with many characters is better when it has less gloss, and it is better to carry out the fixing process in the above process.

Since an image having a smooth surface cannot be overwritten with a pencil or the like, it is better that the image to be overwritten has fine irregularities on the surface, which is suitable for the fixing process.

(4) Fixing Film 124 As the fixing film 124, a single layer or a composite layer film having heat resistance, releasability, durability, etc., of generally 100 μm or less, preferably 40 μm or less can be used.

FIG. 9 is a schematic cross-sectional view of the layer structure of an example of a composite layer film, where 124a is a heat-resistant layer as a base layer (base film) of the fixing film, and 124b is the heat-resistant layer 124.
It is a release layer laminated on the outer surface (a surface facing the toner image) of a.

The heat-resistant layer 124a is made of, for example, polyimide, polyetheretherketone (PEEK), polyethersulfone (PES), polyetherimide (PEI), polyparabanic acid (PPA), or other high heat-resistant resin film, or Ni. Metals such as SUS and Al that have excellent strength and heat resistance can be used.

The release layer 124b is preferably made of fluororesin such as PTFE (polytetrafluoroethylene) / PFA / FEP, or silicon resin. The release layer 124b is laminated on the heat-resistant layer 124a by adhesive lamination of the release layer film and electrostatic coating (coating) of the release layer material.
It can be performed by stacking by a film forming technique such as vapor deposition or CVD, or by coextrusion of a heat-resistant layer material and a release layer material into a two-layer film.

The heat-resistant layer 124a has a thickness equal to that of the release layer 124b.
Since it is set thicker than the thickness of the film, the total thickness of the film can be reduced while maintaining the strength of the film, and the heat transfer efficiency from the heating element to the recording material is high.

The surface resistance of the fixing film 124 may be lowered by a method of mixing a conductive agent such as carbon black, graphite or conductive whiskers into the release layer 124b. In that case, charging of the toner contact surface of the fixing film 124 can be prevented. When the toner contact surface of the fixing film 124 is insulative, the surface of the fixing film is charged and disturbs the toner image on the sheet P, or the toner image is transferred to the fixing film 124 (so-called charging offset). In some cases, these measures can avoid these problems.

In the present invention, the heat capacity of the heating element 122 and the substrate 121 of the heating element 120 is small, and these are thermally insulated by the support 127, so that the surface temperature of the heating element 120 is short. The temperature is raised to a fixing temperature in time. Therefore, there is no need for warm-up time or standby temperature adjustment (heating the heating element in advance), energy can be saved, and the temperature inside the machine can be prevented.

As described above, in this embodiment, the glossiness and smoothness of the image can be easily selected by simply moving the lever L provided outside the (image forming) apparatus up and down, and the quick start and low power consumption can be achieved. It is possible to realize various image forming apparatuses.

Although the surface property of the image can be selected by manually moving the lever L up and down in this embodiment, an electric means for moving the lever up and down by a solenoid or the like may be used.

Further, for example, when a full-color image is formed, a glossy image and a non-glossy image may be formed on a mono-color image. Further, it is also possible to provide a plurality of sending angles to provide a plurality of gloss levels.

<Embodiment 4> In this embodiment (FIG. 9), the transfer material P and the fixing film 12 are used in the step (N to 151) of cooling the molten toner image when the driving roller position is set to 125a.
The backup guide B is provided in order to ensure the close contact of No. By providing the guide B, even the transfer material P which is thin and has no stiffness can be conveyed 151 parts before (before the toner image is sufficiently cooled) without being separated from the fixing film, and a beautiful gloss image can be obtained.

In order to prevent deterioration of the surface property of the fixing film, the upper surface of the guide B (the surface contacting the film 124 via the transfer material) has good slidability like Teflon (registered trademark). It is good that it is made of material.

Further, except when the transfer material passes through the fixing device, it is better to shorten the sliding time between the fixing film 124 and the guide B by setting the driving roller 125 device to 125b, in order to improve the life of the fixing film 124. It is good to prevent the temperature of the guide B from rising and the molten toner image from being insufficiently cooled.

Further, in this embodiment, instead of the backup guide B, a backup belt made of Si rubber or the like may be provided.

In this embodiment, since the backup member is provided, it is not always necessary to feed the film 124 to the pressure roller side (α <0) with respect to the tangential direction of the pressure contact portion. .

<Embodiment 5> In the embodiment, the driving roller 125 is moved to change the feeding direction of the fixing film 124, but in this embodiment, the separating roller 130 is moved as shown in FIG. Therefore, the feeding direction of the fixing film 124 is changed.

When the drive roller 125 is moved, the drive transmission mechanism also has to be moved, which complicates the apparatus. However, by adopting the structure of this embodiment, the fixing film feeding direction can be changed with a simple structure. You can

<Embodiment 6> In this embodiment, as shown in FIG. 10, for example, a separation guide 131 having a tip radius of curvature of about 1 mm.
The feeding direction of the fixing film 124 is changed by moving the position of. Such a separation guide 13
By using 1, it is possible to perform separation with a larger curvature, and stable separation of paper can be achieved. Further, according to the experiments of the present inventors, it is better to use a separation guide having a smaller radius of curvature,
Less offset than using a separation roller (7 mm radius).

The heating device described above is not limited to the image forming device, and is widely used as a device for heating the image carrier such as a device for heating the recording material carrying the image to modify the surface property. Can be used as a device.

[0096]

As described above, according to the first aspect of the present invention, the recording material is pressed against the heating body which is fixed and supported so as to face the heating body via the endless film which is rotationally moved. In the device for heating and fixing the visible image by the member, by making the width of the heating element of the heating element in the film running direction larger than the nip width between the pressing member and the endless film, It has become possible to reduce the amount of wear and significantly reduce the amount of the above-mentioned wear powder adhered to the surface of the heating body. Further, since the temperature distribution in the nip becomes more uniform, the variation in fixing property in the longitudinal direction can be reduced. When h ≧ (H + 0.5), the parallelism between the pressure roll and the heating body at the time of assembly can be improved. Since there is a margin, the manufacturing cost could be reduced.

Further, according to the inventions of claims 3 to 6, by varying the feeding direction of the fixing film on the outlet side of the pressure contact portion, the surface property of the fixed image is changed and the glossiness is improved. You can

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a heating device according to the present invention.

FIG. 2 is an enlarged view of a main part of the heating device shown in FIG.

FIG. 3 is a diagram showing an example of a conventional heating device.

FIG. 4 is an enlarged view of a main part of the heating device of FIG.

FIG. 5 is a diagram showing a second embodiment of the heating device according to the present invention.

FIG. 6 illustrates an image forming apparatus according to a third exemplary embodiment of the present invention.

FIG. 7 illustrates a fixing device according to a third exemplary embodiment of the present invention.

FIG. 8 illustrates a fixing device according to a fourth exemplary embodiment of the present invention.

FIG. 9 illustrates a fixing device according to a fifth exemplary embodiment of the present invention.

FIG. 10 illustrates a fixing device according to a sixth exemplary embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Film 4 ... Pressure roll 20 ... Heating body 21d ... Substrate 21e ... Heating element 21g ... Protective layer 120 ... Heating body 125 ... Driving roller 126 ... Followed roller 130 ... Separation roller 131 ... Separation guide L ... Lever

Claims (2)

[Claims] 1. A heating device in which a heating body is arranged on one side of a film, an image carrier is closely attached to the other side, and heat energy is applied to the image carrier through the film,
The heating element comprises a ceramic substrate, a heat generating layer and a protective layer disposed on the ceramic substrate, and the width of the heat generating layer is formed between a film and a pressure roll that presses the image carrier against the heating element. A heating device characterized by having a larger nip width. 2. An image forming means for forming a non-fixed toner image corresponding to target image information by carrying a toner made of a heat-meltable resin or the like on a recording material surface, a fixing film, and running of the fixing film. A driving unit, a heating body fixedly supported on one side of the fixing film, and a heating body disposed on the other side of the fixing film, and the recording material is unfixed with respect to the heating body via the fixing film. A fixing member provided with a pressure member for closely contacting the surface on which the deposited toner image is carried, and fixed by running in the same direction at the same speed as the carrying speed of the recording material carrying the unfixed toner image carried from the image forming means A heating device comprising: a toner image heat fixing unit that introduces the recording material between a film and the pressure member to heat and fix an unfixed toner image on the surface of the recording material, wherein the heating body and the pressure member. Pressure contact surface with Direction and a heating device characterized in that it comprises a means for changing the angle α formed between the traveling direction of the heat-resistant film on the downstream side of the pressure-contacting portion.