JP2002190369A - Heating device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device to minimally suppress heat losses conveyed to the drive roller for the heat-resisting film and reduce the consumption of heat energy in the heater. SOLUTION: The constitution of the heating device is such as to set an area for the drive roller to abut against the surface of the heat-resisting film at the both ends beyond the paper-processing zone to avoid heat conveyance to the drive roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for fixing an unfixed toner image formed on a recording material (hereinafter, also referred to as a recording material sheet) as a material to be heated by heating and melting the recording material. Alternatively, the present invention relates to a heating device used for heat-treating a recording material to remove wrinkles and gloss of the recording material, and an image forming apparatus using the heating device as a heat fixing device.

[0002]

2. Description of the Related Art Conventionally, a heat fixing device used for heat fixing an unfixed toner image is disclosed in, for example, Japanese Patent Application Laid-Open No.
As disclosed in JP-A-313182 and the like, a heat-resistant film conveyed (moved and driven) while being pressed against a fixedly supported heater (heater), and a recording material is heated via the heat-resistant film. And a pressing member for bringing the unfixed toner image formed and carried on the recording material surface onto the recording material surface by applying heat of the heating body to the recording material via the heat-resistant film. There is an apparatus with a fixing method and configuration, which is already in practical use.

More specifically, a thin heat-resistant film (or sheet), a driving means for moving the heat-resistant film, and a heating means fixedly supported and arranged on one side with the heat-resistant film inside. And a pressure member disposed on the other surface of the recording material so as to face the heating element and closely contact the unfixed toner image (visible image) supporting surface of the recording material with the heating element via a heat-resistant film. The heat-resistant film is moved at substantially the same speed in the forward direction as the recording material conveyed and introduced between the heat-resistant film and the pressure member at least during image fixing.
Then, the traveling heat-resistant film and the recording material are passed through a nip portion N as a fixing portion formed by pressing the heating element and the pressing member, so that the unfixed toner image bearing surface of the recording material is heat-resistant. Heated by a heating element through a heat-resistant film to apply heat energy to the unfixed toner image to soften
This is a heating means / apparatus having a basic configuration of melting and then separating a heat-resistant film and a recording material after passing through a fixing unit at a separation point.

[0004] In such a film heating type heating apparatus, since a heating element and a thin heat-resistant film with a high temperature rise are used, the wait time can be reduced (quick start).
Becomes possible.

FIG. 9 is a perspective view showing a conventional heating device, and FIG. 10 is a cross-sectional view of the heating device. 9 and 10, reference numeral 1 denotes a flat heating element, and a direction (a width direction of the film) crossing a plane movement direction of an endless belt-like heat-resistant film (hereinafter, simply referred to as a fixing film or a film) 2. A low-heat-capacity linear heating element having a long length, which is composed of a heater substrate (ceramic material), a current-generating heating resistor (heating element), a surface protection layer, a temperature detecting element, and the like (not shown). It is fixed and supported. The film 2 is driven to rotate in the direction of the arrow while being guided by a horizontally long heater supporting member 4 made of a thermosetting resin (phenol resin) having high rigidity and high heat resistance.

Reference numeral 3 denotes a fixed pressing member having a small surface friction coefficient. The pressing member 3 is pressed by the pressing spring 12 against the heating element 1 and the heating element supporting member 4 with the film 2 interposed therebetween. A nip portion N is formed therebetween. Reference numeral 5 denotes a rubber drive roller, which is in contact with the outer surface of the film 2. When the drive roller 5 is driven to rotate in the direction of the arrow by a drive source mechanism (not shown), the film 2 is also driven to rotate in the direction of the arrow by the frictional force.

A recording material sheet P carrying on its upper surface an unfixed toner image Ta conveyed from an image forming section (not shown) is guided by guides 6 and 7 to form a nip portion N between the heating element 1 and the pressing member 3. At a position between the fixing film 2 and the pressing member 3, the unfixed toner image surface is brought into close contact with the lower surface of the fixing film 2 which is driven to rotate in the same direction at the same speed as the conveying speed of the recording material sheet P, It passes between the nip portions N between the heating element 1 and the pressure member 3 in an overlapping state with the film.

The heating element 1 is energized and heated to the energizing heating resistor at a predetermined timing, and after the temperature of the heating element 1 detected by the temperature detecting element reaches a predetermined temperature (for example, 200 ° C.), the recording material sheet is heated. P is fed into the nip N. The heat energy of the heating element 1 is
The unfixed toner image Ta is heated in the process of passing through the nip N and becomes a softened / fused image through the nip portion N. softening·
The molten toner is sufficiently cooled and solidified by the time it reaches the paper discharge section, and is in a state Tc in which it is completely fixed on the recording material sheet P.

[0009]

However, in the heating device having the structure as in the above-mentioned conventional example, since a large amount of heat is transmitted to the driving roller via the heat-resistant film, there is a problem that heat energy is lost. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and minimizes heat loss to a driving roller for driving a heat-resistant film, thereby reducing heat energy consumption in a heating element. It is intended to obtain a heating device that performs heating.

Another object of the present invention is to provide an image forming apparatus capable of forming a high quality image by applying the heating device as a heat fixing device.

[0012]

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

(1) A heating member supporting member for holding a substantially flat heating member, a heat-resistant film whose inner surface is opposingly pressed against the heating member and driven to move, and an inner surface of the heat-resistant film that contacts the heating member. A heating member having a film guide member provided, a pressing member forming a nip portion between the heating member with the heat-resistant film interposed therebetween, and a driving roller for driving the heat-resistant film; A heating device wherein a contact surface between a roller and the heat-resistant film is provided in a non-sheet passing area at both ends of the heat-resistant film.

(2) The heating device according to (1), wherein a driving roller for driving the heat-resistant film is arranged so as to be in contact with the inner surface of the heat-resistant film.

(3) The guide member for the heat-resistant film is
The heating device according to (1), wherein a contact surface with the inner surface of the heat-resistant film is partially removed in a paper passing region not supporting the drive roller.

(4) The heating device according to (1), wherein the heat-resistant film is of an endless or roll-up type.

(5) An image forming apparatus comprising: an image forming means for forming and carrying an unfixed toner image on a recording material; and a heat fixing means for heating and fixing the unfixed toner image formed and carried on the recording material to the recording material. In the image forming apparatus, the heating and fixing unit is the heating device according to any one of (1) to (4).

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

(First Embodiment) FIG. 1 is a perspective view showing a heating apparatus according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view of the heating apparatus. 1 and 2, reference numeral 1 denotes a planar heating element, which is a direction (width direction of the film) crossing the plane movement direction of an endless belt-like heat-resistant film (hereinafter, simply referred to as a fixing film or a film) 2. A low-heat-capacity linear heating element having a long length, which includes a heater substrate (ceramic material), a current-generating heating resistor (heating element), a surface protection layer, a temperature detecting element, and the like (not shown). It is fixed and supported. The film 2 is driven to rotate in the direction of the arrow while being guided by a horizontally long heater support member 4 made of a thermosetting resin (phenol resin) having high rigidity and high heat resistance.

Reference numeral 3 denotes a fixed pressure member having a small surface friction coefficient.
A pressure is applied to the heating element 1 and the heating element supporting member 4 to form a nip portion N between the heating element 1 and the film 2. here,
The pressing member 3 is made of, for example, a surface of an elastic member having high heat resistance, low heat capacity, and low thermal conductivity such as a silicon sponge or the like.
It is covered with a heat-resistant material having a small coefficient of friction such as A or PTFE.

The friction coefficient between the outer peripheral surface of the film 2 and the recording material sheet P is μ1, and the recording material sheet P and the pressure member 3
If the friction coefficient between is set to μ2, each friction coefficient is set so as to satisfy the relationship of μ1> μ2.

Numeral 8 denotes a rubber driving roller, which is configured to circumscribe the film 2 only in the non-sheet passing areas at both ends. When the drive roller 8 is rotationally driven in the direction of the arrow by a drive source mechanism (not shown), a recording material sheet as a heated material carrying on its upper surface an unfixed toner image Ta conveyed from an image forming unit (not shown). The recording material sheet P is rotated in the direction of the arrow at a peripheral speed substantially equal to the transport speed (process speed) of P, and is transported by frictional force.

When the driving of the film 2 and the energization of the heating element 1 are performed, the recording material sheet P carrying the unfixed toner image Ta is pressed against the film 2 in the nip portion N by flat pressing. When the recording material sheet P is introduced between the member 3 and the image bearing surface upward, the recording material sheet P comes into close contact with the surface of the film 2 and moves and passes through the nip portion N together with the film. In the above, the thermal energy of the heating element 1 in contact with the inner surface of the film 2 is applied to the recording material sheet P via the film, and the unfixed toner image Ta becomes a softened and fused image.

At this time, the heat energy received by the heating element 1 of the film 2 is also transmitted to the drive roller 8 circumscribing the film 2, but the contact surface with the film 2 is changed only in the non-sheet passing area at both ends. Therefore, the contact area with the film is small and the heat capacity of the drive roller 8 itself is also small, so that the loss of heat energy to the drive roller 8 can be suppressed.

More specifically, in the conventional configuration shown in FIGS. 9 and 10, an average power of 400 W was required to control the temperature at 200 ° C., but by using this embodiment, 280 W was obtained.
And energy saving was achieved in about 2/3. Also, regarding the quick start property, the start-up time, which was 8 seconds in the conventional configuration, could be reduced to 5 seconds. After that, the toner is sufficiently cooled and solidified by the time the softened and fused image reaches the paper discharge section, and is in a state Tc in which the toner is completely fixed on the recording material sheet P.

(Second Embodiment) FIG. 3 is a transverse sectional view showing a heating device according to a second embodiment of the present invention, and FIG. 4 is a perspective view of a driving roller in the heating device. In the second embodiment, the drive roller in the first embodiment is disposed so as to be in contact with the inner surface of the film.

In FIG. 3, reference numeral 9 denotes a horizontally long heating member supporting member made of a thermosetting resin (phenol resin) having high rigidity and high heat resistance, which supports the heating member 1 and is integrated with the heating member supporting member. It has a provided film guide 9-a, and guides a part of the film 2. Note that the heating member support member 9 is fixed to the main body device.

Reference numeral 3 denotes a fixed pressure member having a small surface friction coefficient.
A pressure is applied to the heating element 1 and the heating element support member 9 to form a nip N between the heating element 1 and the film 2.

Reference numeral 11 denotes a drive roller for driving the film 2, and only the non-sheet passing portions at both ends are inscribed in the film 2. Here, the drive roller 11 is pressed against the inner surface of the film 2 by a pressure spring 10 fixed to the main body device. When the drive roller 11 rotates in the direction of the arrow by a drive source mechanism (not shown), the drive roller 11 The film 2 is also driven and rotated by the frictional force between the films 2 in the direction of the arrow.

By adopting such a configuration, the amount of heat released from the drive roller 11 to the outside of the heating device is reduced as compared with the configuration shown in the first embodiment, and the energy loss is further reduced. It can be suppressed. Specifically, by using this embodiment, the average power consumption required for controlling the temperature to 200 ° C. was 250 W, which was further reduced by 30 W from the above-described first embodiment.

(Third Embodiment) FIG. 5 is a perspective view showing a heating device according to a third embodiment of the present invention. In the third embodiment, the film guide member in the first embodiment has a shape in which a contact surface with a film is partially deleted in a paper passing area where a driving roller is not supported.

In FIG. 5, reference numeral 1 denotes a flat heating element, and a direction (a width direction of the film) crossing a plane moving direction of an endless belt-like heat-resistant film (hereinafter, simply referred to as a fixing film or simply a film) 2 is shown. A low-heat-capacity linear heating element with a long length, and a heater substrate (ceramic material)
It consists of a current-generating heating resistor (heating element), a surface protection layer, a temperature detecting element, etc., and is fixed to and supported by the film guide member 13. The film 2 is driven and rotated in the direction of the arrow while being guided by a horizontally long film guide member 13 made of a thermosetting resin (phenol resin) having high rigidity and high heat resistance.

Reference numeral 3 denotes a fixed pressure member having a small surface friction coefficient. The pressure member 3 sandwiches the film 2 by a pressure spring 12 (see FIGS. To form a nip Ng with the film 2.

Reference numeral 8 denotes a driving roller made of rubber, which is configured to circumscribe the film 2 only in the non-sheet passing areas at both ends. Here, the film guide member 13 supports the drive roller 8 from the inside of the film 2 in the non-sheet passing area at both ends. Further, the film guide member 13 is connected to the drive roller 8.
In the paper passing area not circumscribing the film 2, the surface inscribed with the film 2 has a shape in which a part 13 a is deleted.

By adopting such a configuration, the film guide member 13 can be compared with the configuration shown in the first embodiment.
The amount of heat conducted to the substrate is reduced, and the energy loss can be further reduced. Specifically, by using this embodiment, the average power consumption required for controlling the temperature at 200 ° C. was 240 W, which was further reduced by 40 W from the first embodiment described above. In addition, the quick start-up time was 4 seconds, and it was possible to shorten the start-up time to half the conventional one.

(Fourth Embodiment) FIG. 6 is a perspective view showing a heating device according to a fourth embodiment of the present invention, and FIG. 7 is a cross-sectional view of the heating device. In each of the above embodiments, the endless film 2 is shown. However, as shown in FIGS. 6 and 7, the film 2 sent out from the feeding roller 41 is moved between the heating body 1 and the pressing member 3. The driving roller 8 is wound around the winding roller 42 through the nip N, and the driving roller 8 is
The film 2 can be driven in the non-sheet passing area at both ends. In this case, the winding roller 42 is driven in the winding direction by, for example, a driving force of a coil spring (not shown).

(Fifth Embodiment) FIG. 8 is a block diagram of an image forming apparatus in which the heating device shown in each of the above embodiments is applied as a heat fixing device. In FIG. 8, reference numeral 51 denotes a photosensitive drum, which is OPC, amorphous Se, amorphous Si.
Are formed on a cylindrical substrate such as aluminum or nickel. The photosensitive drum 51 is driven to rotate in the direction of the arrow, and its surface is first uniformly charged by a charging roller 52 as a charging device.

Next, the charged surface of the photosensitive drum 51 is irradiated with a laser beam 53 controlled to be ON or OFF in accordance with image information.
Is performed to form an electrostatic latent image. This electrostatic latent image is developed and visualized by the developing device 54. As a development method, a jumping development method, a two-component development method, or the like is used, and image exposure and reversal development are often used in combination.

The visualized unfixed toner image Ta is transferred from the photosensitive drum 51 onto the recording material P conveyed at a predetermined timing by a transfer roller 55 as a transfer device. Here, the sensor 58 detects the leading end of the recording material so that the image forming position of the unfixed toner image Ta on the photosensitive drum 51 matches the writing start position of the leading end of the recording material, and the timing is adjusted. The recording material P conveyed at a predetermined timing is nipped and conveyed by the photosensitive drum 51 and the transfer roller 55 with a constant pressing force. This unfixed toner image T
The recording material P to which a is transferred is conveyed to the heat fixing device 56 according to the present invention, and passes through the heat fixing device 56, whereby the unfixed toner image Ta is fixed on the recording material P as a permanent image. On the other hand, the transfer residual toner remaining on the photosensitive drum 51 is removed from the surface of the photosensitive drum 51 by the cleaning device 57.

[0040]

As described above, according to the present invention,
Since the contact surface of the drive roller with the heat-resistant film is limited to the non-sheet passing area at both ends, the amount of heat released to the drive roller through the heat-resistant film is minimized, and power consumption in the heating element is reduced. This makes it possible to provide a heating device that consumes less heat energy and has a high quick start property.

According to the present invention, in addition to the above configuration, the drive roller is disposed so as to be in contact with the inner surface of the film, so that the amount of heat transmitted to the drive roller is released into the air outside the heating device. Therefore, there is an effect that the power consumption in the heating element can be further reduced.

According to the present invention, in addition to the above structure, the film guide member has a shape in which the contact surface with the film is partially removed in the paper passing area where the drive roller is not supported. It has the effect of suppressing the heat generated in the body from escaping to the film guide member via the film, and has the effect of enabling the power consumption in the heating body to be further reduced.

Further, according to the present invention, since the heat-resistant film is of an endless or roll-up type, it is possible to discharge the wear debris of the recording material in the nip portion N by moving the film and prevent the recording material from staying. There is an effect that accurate heat treatment can always be performed.

Further, according to the present invention, since the heating device of the present invention is applied as a heat source for heating and fixing an unfixed toner image on a recording material, there is an effect that a high quality image forming apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a heating device according to a first embodiment.

FIG. 2 is a cross-sectional view of the heating device according to the first embodiment.

FIG. 3 is a cross-sectional view of a heating device according to a second embodiment.

FIG. 4 is a perspective view showing a driving roller according to a second embodiment.

FIG. 5 is a perspective view of a drive roller and a heat-resistant film showing a third embodiment.

FIG. 6 is a cross-sectional view of a heating device according to a fourth embodiment.

FIG. 7 is a perspective view showing a driving roller according to a fourth embodiment.

FIG. 8 is a schematic diagram illustrating an image forming apparatus according to a fifth embodiment.

FIG. 9 is a perspective view showing a conventional example.

FIG. 10 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 ··· Heating body 2 ··· Film 3 ··· Pressing member 4, 9, 13 ··· Heating member support member 5, 8, 11 ··· Conventional hummum drive roller 6, 7 ··· Sheet transport guides 10, 12 ··· Pressing panel P ··· Recording material sheet N ··· Nip portion N Ta ··· Unfixed toner image Tc ··· Fixed toner image 51 ··· Photosensitive drum 52 ··· Charging roller 53 ··· Laser beam 54 ··· Development Device 55: Transfer roller 56: Heat fixing device 57: Cleaning device 58: Sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoru Taniguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Ken Murooka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Ken Nakagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Akira Kato 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. F Terms (reference) 2H033 AA15 BA11 BA12 BA26 BA27 BE03 3K058 AA81 AA87 BA18 CE13 DA04 GA06

Claims (5)

[Claims] 1. A heating element supporting member for holding a substantially flat heating element, a heat-resistant film whose inner surface is opposingly pressed against the heating element and driven to move, and an inner surface of the heat-resistant film provided to be in contact with the heating element. A heating member having a film guide member, a pressing member forming a nip between the heating member with the heat-resistant film interposed therebetween, and a driving roller for driving the heat-resistant film. And a contact surface of the heat-resistant film is provided in a non-sheet passing area at both ends of the heat-resistant film. 2. The heating device according to claim 1, wherein a driving roller for driving the heat resistant film is arranged so as to be in contact with an inner surface side of the heat resistant film. 3. The heat-resistant film guide member has a shape in which a contact surface with an inner surface of the heat-resistant film is partially deleted in a paper passing area that does not support the drive roller. Item 6. The heating device according to Item 1. 4. The heating device according to claim 1, wherein said heat-resistant film is of an endless or roll-up type. 5. An image forming apparatus comprising: an image forming unit for forming and supporting an unfixed toner image on a recording material; and a heat fixing unit for heating and fixing the unfixed toner image formed and supported on the recording material to the recording material. 5. The image forming apparatus according to claim 1, wherein the heat fixing unit is the heating device according to claim 1.