JP2018054897A - Heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heater which can excellently suppress breakage of a rotational member with a heat generation layer.SOLUTION: The heater includes: a heating rotational member 1 having a heat generation layer 13, the heat generation layer generating heat by electric conduction; electricity supply members 5a and 5b which form electricity-supplied regions F1 and F2 by getting in contact with the heat generation layer; and a pressurizing rotational member 3 which forms nip regions N1 and N2 by getting in contact with the heating rotational member, the nip regions heating an image T supported by a recording material P and the electricity-supplied regions being located on the inner side of the nip regions alone.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a heating device suitable for use as a fixing device mounted on an image forming apparatus such as an electrophotographic copying machine or an electrophotographic printer.

  In an electrophotographic copying machine or printer, a toner image is formed on a recording material by an image forming unit, and the recording material is heated by a fixing device to fix an unfixed toner image on the recording material.

  Patent Document 1 discloses a fixing device that heats a recording material carrying a toner image at a fixing nip formed by a fixing belt having a heating element and a pressure belt and heats the recording material to fix the toner image on the recording material. It is disclosed.

  A printer equipped with this type of fixing device has a short time (first print out time (hereinafter referred to as FPOT)) from the input of a print command to the output of the first image, and low power consumption. It is also excellent in terms of speeding up.

JP 2007-272223 A

  In the fixing device disclosed in Patent Document 1, as shown in FIG. 3A of Patent Document 1, the fixing belt is longer than the pressure roll in the longitudinal direction perpendicular to the conveyance direction of the recording material. Is longer than the fixing belt. Power supply terminals for supplying power to the heating element of the fixing belt are provided at both ends of the belt support holder (see paragraph 0070). In this configuration, an area where the pressure roll does not press the power supply terminal via the fixing belt occurs in the longitudinal direction perpendicular to the recording material conveyance direction.

  Further, as shown in FIG. 3B of Patent Document 1, the length of the power supply terminal is longer than the fixing nip formed by the pressure roll and the fixing belt in the recording material conveyance direction. Even in this configuration, an area in which the pressure roll does not press the power supply terminal via the fixing belt occurs in the recording material conveyance direction.

  That is, in the fixing device of Patent Document 1, there is an unstable contact region where no pressing force is applied in the contact region between the power supply terminal and the fixing belt in the longitudinal direction perpendicular to the recording material conveyance direction and the recording material conveyance direction. Exists.

  In the fixing device disclosed in Patent Document 1, if conveyance of the recording material is repeated at the fixing nip, there is a possibility that scraping powder of the fixing belt or sliding grease applied to the inner peripheral surface of the fixing belt is fixed to the surface of the power supply terminal. When the sliding grease adheres to the surface of the power supply terminal, the conduction path between the power supply terminal and the fixing belt becomes unstable, and abnormal discharge may occur in the region of unstable contact between the power supply terminal and the fixing belt. If abnormal discharge occurs, the fixing belt may be damaged (for example, perforated).

  The objective of this invention is providing the heating apparatus excellent in suppression of the failure | damage of the heating rotation member which has a heat generating layer.

In order to achieve the above object, the heating device according to the present invention comprises:
A heating rotating member having a heat generating layer that generates heat when energized;
A power supply member that forms a power supply region in contact with the heat generating layer;
A pressure rotary member that contacts the heating rotary member to form a nip region;
A heating device for heating an image carried by the recording material in the nip region,
The power feeding area is arranged only inside the nip area.

Moreover, the heating device according to the present invention comprises:
A heating rotating member having a heat generating layer that generates heat when energized;
A power supply member that forms a power supply region in contact with the heat generating layer;
A pressure rotary member that contacts the heating rotary member to form a nip region;
A pressurizing auxiliary member that is in contact with the heating rotary member to form a power feeding facing region;
A heating device for heating an image carried by the recording material in the nip region,
The power feeding area is arranged only inside the power feeding facing area.

  ADVANTAGE OF THE INVENTION According to this invention, provision of the heating apparatus which is excellent in suppression of the failure | damage of the heating rotation member which has a heat generating layer is realizable.

Sectional drawing which shows schematic structure of the fixing apparatus which concerns on Example 1. FIG. Figure when the fixing device is viewed from the upstream side in the paper transport direction The figure for demonstrating the nip area | region and electric power feeding area | region of a fixing device Sectional drawing which shows layer structure of a film and a pressure roller The figure for demonstrating the relationship between a holder, the sliding plate of a sliding member, and a feeding electrode The figure for demonstrating the nip area | region and electric power feeding area | region of the fixing apparatus which concerns on the comparative example 1. The figure for demonstrating the nip area | region and electric power feeding area | region of the fixing apparatus which concerns on the comparative example 2. FIG. 6 is a diagram for explaining a nip region and a power feeding region of the fixing device according to the second embodiment. Sectional drawing which shows schematic structure of the fixing apparatus which concerns on Example 3. FIG. Figure when the fixing device is viewed from the upstream side in the paper transport direction The figure for demonstrating the nip area | region and electric power feeding area | region of a fixing device The figure for demonstrating the nip area | region and electric power feeding area | region of the fixing apparatus which concerns on the comparative example 3. The figure for demonstrating the nip area | region and electric power feeding area | region of the fixing apparatus which concerns on the comparative example 4. Sectional drawing which shows schematic structure of image forming apparatus

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Although the preferred embodiment of the present invention is an example of the best embodiment of the present invention, the present invention is not limited by the following examples, and various other configurations are within the scope of the idea of the present invention. It is possible to replace with.

(1) Image Forming Apparatus An image forming apparatus equipped with the heating device according to the present invention as a fixing device will be described with reference to FIG. FIG. 14 is a cross-sectional view showing a schematic configuration of an example of an image forming apparatus (a monochrome printer in this embodiment) using an electrophotographic recording technique.

  In the image forming apparatus, an image forming unit 100 that forms a toner image on a sheet P as a recording material includes a photosensitive drum 101 as an image carrier, a charging member 102, and a laser scanner 103. Further, the image forming unit 100 includes a developing device 104, a cleaner 106 that cleans the outer peripheral surface (surface) of the photosensitive drum 101, and a transfer member 105. Since the operation of the image forming unit 100 described above is well known, detailed description thereof is omitted.

  The paper P stored in a cassette (not shown) is conveyed to a transfer portion formed by the photosensitive drum 101 and the transfer member 105 by rotation of a roller (not shown). The paper P on which the toner image is transferred by the transfer unit is sent to a fixing device (fixing unit) 107, and the toner image is heated and fixed on the paper by the fixing device. The paper P exiting the fixing device 107 is discharged to a tray (not shown) by the rotation of the roller 108.

(2) Fixing device 107
FIG. 1 is a cross-sectional view showing a schematic configuration of the fixing device 107 of the present embodiment. FIG. 2 is a diagram when the fixing device 107 is viewed from the upstream side in the conveyance direction of the paper P. FIG.

  The fixing device 107 of the present embodiment includes a cylindrical film 1 as a heating rotation member, a holder 2 as a support member, and a pressure roller 3 as a pressure rotation member. Furthermore, the fixing device 107 includes a sliding member 4, power supply electrodes 5 a and 5 b as power supply members, a stay 6 as a pressure member, a temperature detection member 7 such as a thermistor, and a power supply cable 8.

  FIG. 4A shows a cross-sectional view of the film 1.

  The outer diameter of the film 1 is 18 mm. In the longitudinal direction orthogonal to the transport direction of the paper P, the length of the film 1 is 250 mm (see FIG. 3B). The film 1 has a cylindrical heat generating layer 13 that generates heat when energized. An elastic layer 12 is provided on the outer periphery of the heat generating layer 13, and a release layer 11 is provided on the outer periphery of the elastic layer. The film thickness of the heat generating layer 13 is 50 μm, the film thickness of the elastic layer 12 is 150 μm, and the film thickness of the release layer 11 is 15 μm.

The material of the release layer 11 is PFA, and the material of the elastic layer 12 is silicone rubber. The material of the heat generating layer 13 is polyimide added with carbon black, which is a conductive filler. The volume resistivity of the heat generating layer 13 is 2.6 × 10 ⁻⁴ [Ω · m], and the actual resistance value at both ends in the longitudinal direction perpendicular to the transport direction of the paper P is about 20Ω.

  FIG. 4B shows a cross-sectional view of the pressure roller 3.

  The pressure roller 3 has a metal core 33 having an outer diameter of 10 mm. An elastic layer 32 made of silicone rubber having a thickness of 4 mm is provided on the outer periphery of the core metal 33, and a release layer 31 made of PFA having a thickness of 30 μm is provided on the outer periphery of the elastic layer. The pressure roller 3 can be elastically deformed by the elastic layer 32 in the radial direction of the pressure roller. The outer diameter of the pressure roller 3 is about 18 mm. Further, the hardness of the pressure roller 3 is 40 degrees under a 1 kgf load of the Asker C-type hardness meter.

  In the longitudinal direction perpendicular to the transport direction of the paper P, the lengths of the elastic layer 32 and the release layer 31 of the pressure roller 3 are 240 mm (see FIG. 3B). In the longitudinal direction perpendicular to the conveyance direction of the paper P, both ends of the cored bar 33 of the pressure roller 3 are rotatably supported by the frames FL and FR of the fixing device 107 via bearings 10L and 10R (FIG. 2). reference).

  In FIG. 5A, a cross-sectional view of the holder 2 is shown on the left side. On the right side, the holder 2 and the sliding plates 4a, 4b, 4c and the feeding electrodes 5a, 5b of the sliding member 4 arranged in the holder in the longitudinal direction orthogonal to the transport direction of the paper P are shown. In FIG. 5B, on the left side, a cross-sectional view of the holder 2 in which the sliding plates 4a, 4b, 4c of the sliding member 4 and the feeding electrodes 5a, 5b are arranged is shown. On the right side, the holder 2 in which the sliding plates 4a, 4b, 4c of the sliding member 4 and the feeding electrodes 5a, 5b are arranged is shown.

  The holder 2 made of heat resistant resin that penetrates the inside of the film 1 has a length of 250 mm in the longitudinal direction perpendicular to the transport direction of the paper P. Both ends in the longitudinal direction are supported by the frames FL and FR (see FIG. 2). The material of the holder 2 is a liquid crystal polymer. In the conveyance direction of the paper P, a concave portion 2a having a depth of 1 mm is provided in the center of the arcuate surface of the holder 2 on the pressure roller 3 side.

  The sliding plates 4 a, 4 b, 4 c and the feeding electrodes 5 a, 5 b are each formed in a flat plate shape and are fitted into the recess 2 a of the holder 2. The material of the power supply electrodes 5a and 5b is an aluminum plate. A power supply cable 8 is electrically connected to the power supply electrodes 5a and 5b (see FIG. 3B). In order to ensure insulation against these power supply electrodes 5a and 5b, the sliding plates 4a, 4b and 4c use glass plates.

  In the longitudinal direction orthogonal to the conveyance direction of the paper P, the sliding plates 4a and 4c formed shorter than the sliding plate 4b are fixedly disposed at both ends of the holder 2, and the sliding plate 4b is a central portion of the holder 2. Fixedly arranged. The feeding electrode 5a is fixedly disposed between the sliding plate 4a and the sliding plate 4b, and the feeding electrode 5b is fixedly disposed between the sliding plate 4b and the sliding plate 4c.

  Regarding the sliding plates 4a and 4c, the dimension in the longitudinal direction perpendicular to the transport direction of the paper P is 10 mm. The dimension in the conveyance direction of the paper P is 3 mm. The thickness is 1 mm. Regarding the sliding plate 4b, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 220 mm. The dimension in the conveyance direction of the paper P is 3 mm. The thickness is 1 mm. Regarding the power supply electrodes 5a and 5b, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 5 mm. The dimension in the conveyance direction of the paper P is 3 mm. The thickness is 1 mm.

  A stay 6 having a U-shaped cross section is placed on the flat surface of the holder 2 opposite to the pressure roller 3. The material of the stay 6 is a gin-coated steel plate. In the longitudinal direction perpendicular to the transport direction of the paper P, both ends of the stay 6 are supported by the frames FL and FR (see FIG. 2).

  The temperature detection element 7 is installed in the holder 2 and is in contact with the inner peripheral surface (inner surface) of the film 1. The temperature detection element 7 detects the temperature of the film 1 and outputs it to a temperature control unit (not shown).

  In order to improve the slidability of the film inner surface, the sliding plates 4a, 4b, 4c, and the feeding electrodes 5a, 5b on the inner surface of the film 1, 400 mg of heat-resistant sliding grease mainly composed of fluorine oil and PTFE is provided. It is applied.

<Nip regions N1, N2 and power feeding regions F1, F2>
The nip regions N1 and N2 and the power feeding regions F1 and F2 of the fixing device 107 will be described with reference to FIG.

  3, (a) is a view showing the film 1, the pressure roller 3, and the power supply cable 8, and (b) is a slide plate 4a, 4b, 4c, power supply electrodes 5a and 5b, a nip region N1, and a power supply region F1. (C) is the A1-A1 sectional view taken on the line of (a).

  With respect to the longitudinal direction orthogonal to the transport direction of the paper P, both ends of the stay 6 are pressed in the vertical direction orthogonal to the generatrix direction of the film 1 by pressurizing springs 11L and 11R (see FIG. 2). The stay 6 uniformly presses the holder 2 in the longitudinal direction perpendicular to the transport direction of the paper P by the pressure of the pressurizing springs 11L and 11R. As a result, the holder 2 presses the sliding plates 4a, 4b, 4c and the feeding electrodes 5a, 5b against the inner surface of the heat generating layer 13 of the film 1 so that the outer peripheral surface (surface) of the film becomes the outer peripheral surface (surface) of the pressure roller 3. ). The pressing force of the film 1 surface against the pressure roller 3 surface is 160N.

  At this time, the pressure roller 3 faces the power supply electrodes 5 a and 5 b with the film 1 in the longitudinal direction perpendicular to the transport direction of the paper P. Since the power supply electrodes 5a and 5b are arranged at positions where the elastic deformation of the pressure roller 3 is maximized in the conveyance direction of the paper P, the pressing force to each power supply electrode can be increased. Therefore, the power feeding electrodes 5 a and 5 b can be stably brought into contact with the heat generating layer 13 of the film 1. As a result, nip regions N1 and N2 and power feeding regions F1 and F2 shown in FIGS. 3B and 3C are formed.

  Here, the nip regions N1 and N2 are regions in which the surface of the film 1 and the surface of the pressure roller 3 are in contact with each other and the film surface and the surface of the pressure roller are pressed by the pressure springs 11L and 11R. The power supply regions F1 and F2 are regions where the power supply electrodes 5a and 5b and the heat generating layer 13 of the film 1 are in contact with each other.

  3B and 3C, the nip region in the longitudinal direction orthogonal to the transport direction of the paper P is denoted by N1, and the nip region in the transport direction of the paper P is denoted by N2. 3B and 3C, a power feeding area in the longitudinal direction perpendicular to the transport direction of the paper P is denoted by F1, and a power feeding area in the transport direction of the paper P is denoted by F2.

  The length of the nip region N1 is 240 mm, and the length of the nip region N2 is 8 mm. The length of the power feeding area F1 is 5 mm, and the length of the power feeding area F2 is 3 mm. In the longitudinal direction perpendicular to the transport direction of the paper P and the transport direction of the paper, the power feeding regions F1 and F2 are contained in the nip regions N1 and N2. That is, the power supply areas F1 and F2 are arranged only in the nip areas N1 and N2 (inside the nip areas N1 and N2). Therefore, pressurization of the power supply electrodes 5a and 5b can be ensured with respect to the heat generating layer 13 of the film 1, and the contact between the heat generating layer and the power supply electrode is stabilized.

<Heat fixing processing operation>
The driving force of the motor M (see FIG. 2) is transmitted to the cored bar 33 of the pressure roller 3 through the gear G, whereby the pressure roller rotates in the direction of the arrow shown in FIG. The film 1 rotates in the direction of the arrow shown in FIG. 1 following the rotation of the pressure roller 3 while the film inner surface is in sliding contact with the sliding plates 4a, 4b, 4c and the feeding electrodes 5a, 5b.

  When power is supplied from the AC power source V to the heat generating layer 13 of the film 1 via the power supply electrodes 5a and 5b and the power supply cable 8, the heat generating layer generates heat and the film rapidly rises in temperature. The temperature control unit controls the amount of power supplied to the heat generating layer 13 so that the temperature detected by the temperature detecting member 7 is maintained at a predetermined fixing temperature (target temperature).

  The paper P carrying the unfixed toner image T is introduced into the nip areas N1 and N2. The sheet P is heated by the heat of the film 1 while being conveyed in the nip areas N1 and N2. As a result, the toner image T on the paper is fixed on the paper.

<Comparison Evaluation of Fixing Device 107>
In order to confirm the operation of the fixing device 107 of this example, a comparative evaluation was performed by using the fixing device of Comparative Example 1 and the fixing device of Comparative Example 2, focusing on the presence or absence of abnormal discharge and film breakage.

(Comparative Example 1)
FIG. 6 shows a fixing device of Comparative Example 1. 6A shows the film 1, the pressure roller 3, and the power supply cable 8. FIG. 6B shows the slide plates 4a, 4b and 4c, the power supply electrodes 5a and 5b, the nip region N1, and the power supply region F1. The figure for demonstrating (c) is the A2-A2 sectional view taken on the line of (a).

  Unlike the configuration of the present embodiment, the comparative example 1 does not have the sliding plates 4a and 4c, and extends the feeding electrodes 5a and 5b in the longitudinal direction orthogonal to the transport direction of the paper P. Regarding the power supply electrodes 5a and 5b, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 15 mm. The dimension in the conveyance direction of the paper P is 3 mm. The thickness is 1 mm.

  The lengths of N1, N2, F1, and F2 at this time are 240 mm, 8 mm, 15 mm, and 3 mm, respectively.

  As shown in FIG. 6B, the power feeding area F1 protrudes from the nip area N1 in the longitudinal direction perpendicular to the transport direction of the paper P. On the other hand, in the transport direction of the paper P, as shown in FIG. 6C, the power feeding area F2 is within the nip area N2. As shown in FIG. 6B, in the power feeding region F1, the power feeding electrodes 5a and 5b are not pressed against the inner surface of the film 1 in the longitudinal direction perpendicular to the transport direction of the paper P (non-pressurizing). Area) has occurred. Therefore, in the longitudinal direction orthogonal to the transport direction of the paper P, the contact between the heat generating layer 13 of the film 1 and the power feeding electrodes 5a and 5b becomes unstable.

(Comparative Example 2)
FIG. 7 shows a fixing device of Comparative Example 2. 7A shows the film 1, the pressure roller 3, and the power supply cable 8. FIG. 7B shows the sliding plates 4a, 4b and 4c, the power supply electrodes 5a and 5b, the nip region N1, and the power supply region F1. (C) is the A3-A3 sectional view taken on the line of (a).

  In the second comparative example, unlike the configuration of the first embodiment, the dimensions of the sliding plates 4a, 4b, 4c and the feeding electrodes 5a, 5b are 6 mm in the transport direction of the paper P. Regarding the power supply electrodes 5a and 5b, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 5 mm. The dimension of the conveyance direction of the paper P is 6 mm. The thickness is 1 mm. The pressure roller 3 includes a core metal 33 having an outer diameter of 4 mm, an elastic layer 32 made of silicone rubber having a thickness of 3 mm, and a release layer 31 made of PFA having a thickness of 30 μm. In the longitudinal direction perpendicular to the transport direction of the paper P, the length of the elastic layer 32 and the release layer 31 is 240 mm, and the outer diameter of the pressure roller 3 is 12 mm.

  The lengths of N1, N2, F1, and F2 at this time are 240 mm, 4 mm, 5 mm, and 6 mm, respectively.

  As shown in FIG. 7C, the feeding area F2 protrudes from the nip area N2 in the conveyance direction of the paper P. On the other hand, in the longitudinal direction orthogonal to the transport direction of the paper P, as shown in FIG. 7B, the power supply region F1 is within the nip region N1. As shown in FIG. 7C, in the power feeding area F2, there is an area where the power feeding electrodes 5a and 5b are not pressed against the inner surface of the film 1 (non-pressurizing area) in the conveyance direction of the paper P. ing. Therefore, in the conveyance direction of the paper P, the contact between the heat generating layer 13 of the film 1 and the power feeding electrodes 5a and 5b becomes unstable.

  In the comparative evaluation, the rotation temperature adjustment operation of the film 1 is performed by a temperature adjustment control unit using a pressure roller rotation jig (not shown) and a temperature detection element (not shown). The operating conditions are AC power supply 100V, evaluation environment temperature 23 ° C., humidity 50%, conveyance speed 100 mm / sec of paper P by nip areas N 1 and N 2, temperature adjustment temperature 200 ° C., and rotation temperature adjustment operation of film 1 is 30 Minutes. At this time, the occurrence of abnormal discharge and the damage of the film 1 are confirmed. The presence or absence of abnormal discharge is confirmed visually and by an EMI locator (Neosystem ES-300V).

  Table 1 shows the results of comparative evaluation. “X” indicates that the film 1 is damaged, “O” indicates that the film 1 is not damaged, and “X” indicates that the abnormal discharge is visually confirmed or the buzzer of the EMI locator sounds (with abnormal discharge). To do. The case where the abnormal discharge cannot be confirmed visually and the buzzer of the EMI locator does not sound is indicated as “◯”.

  In Example 1 (this example), the film 1 was not damaged and no abnormal discharge occurred.

  In the present embodiment, power feeding areas F1 and F2 are arranged in the nip areas N1 and N2. That is, the contact between the heat generating layer 13 of the film 1 and the feeding electrodes 5a and 5b is stabilized, and the generation of voids between them can be suppressed. As a result, the occurrence of abnormal discharge between the feeding electrodes 5a and 5b and the film 1 was suppressed, and as a result, film breakage could be suppressed.

  In Comparative Example 1, film 1 was damaged and abnormal discharge occurred.

  In Comparative Example 1, the power feeding area F1 extends outside the nip area N1. The area protruding from the nip area N1 is not pressed by the pressure roller 3. In the region protruding from the nip region N1, the contact between the heat generating layer 13 of the film 1 and the feeding electrodes 5a and 5b is unstable, and a gap may be generated between the two. In addition, there is rarely a moment when a current path is generated between the gaps due to the sliding grease and film scraping powder adhering to the surfaces of the power supply electrodes 5a and 5b. Thereby, it is considered that abnormal discharge occurs between the power supply electrodes 5a and 5b and the film 1 to damage the film.

  In Comparative Example 2, as in Comparative Example 1, the film 1 was damaged and abnormal discharge occurred.

  In Comparative Example 2, the power feeding area F2 extends outside the nip area N2. The area protruding from the nip area N2 is not pressed by the pressure roller 3. In the region protruding from the nip region N2, the contact between the heat generating layer 13 of the film 1 and the feeding electrodes 5a and 5b is unstable, and a gap may be generated between the two. In addition, there is rarely a moment when a current path is generated between the gaps due to the sliding grease and film scraping powder adhering to the surfaces of the power supply electrodes 5a and 5b. Thereby, it is considered that abnormal discharge occurs between the power supply electrodes 5a and 5b and the film 1 to damage the film.

  As described above, in the fixing device 107 of this embodiment, the power feeding areas F1 and F2 are arranged in the nip areas N1 and N2. Therefore, the conduction path between the power supply electrodes 5a and 5b and the heat generating layer 13 of the film 1 is stabilized, the generation of a gap between the power supply electrode and the film can be suppressed, and the occurrence of abnormal discharge between the power supply electrode and the film can be suppressed. As a result, film breakage could be suppressed.

[Example 2]
Another example of the fixing device 107 will be described. The fixing device 107 of this embodiment is a device configured to compensate for the problems of the fixing device of Comparative Example 1 described above. In the present embodiment, only a configuration different from the fixing device 107 of the first embodiment will be described.

  FIG. 8 shows the fixing device 107 of this embodiment. 8A is a view showing the film 1, the pressure roller 3, and the power supply cable 8. FIG. 8B is a view for explaining the sliding plate 4b, the power supply electrodes 5a and 5b, the nip region N1, and the power supply region F1. (C) is the A4-A4 sectional view taken on the line of (a).

  As shown in FIG. 8B, the fixing device 107 according to the present exemplary embodiment has the lengths of the elastic layer 32 and the release layer 31 of the pressure roller 3 in the longitudinal direction perpendicular to the conveyance direction of the paper P. 260 mm, which is extended in the longitudinal direction as compared with Comparative Example 1. In the fixing device 107 of this embodiment, the sliding plates 4a and 4c are not installed, and the feeding electrodes 5a and 5b are extended in the longitudinal direction orthogonal to the transport direction of the paper P. The dimensions of the power supply electrodes 5a and 5b are the same as those in Comparative Example 1, and the dimension in the longitudinal direction perpendicular to the transport direction of the paper P is 15 mm, the dimension in the transport direction of the paper P is 3 mm, and the thickness is 1 mm.

<Nip regions N1, N2 and power feeding regions F1, F2>
As shown in FIG. 8B, the length of the nip region N1 in the longitudinal direction perpendicular to the conveyance direction of the paper P is 250 mm, and the length of the power feeding region F1 is 15 mm. As shown in FIG. 8C, the length of the nip region N2 in the transport direction of the paper P is 8 mm, and the length of the power feeding region F2 is 3 mm. In the longitudinal direction perpendicular to the transport direction of the paper P and the transport direction of the paper, the power feeding regions F1 and F2 are contained in the nip regions N1 and N2. That is, the power feeding areas F1 and F2 are arranged only in the nip areas N1 and N2. Therefore, pressurization of the power supply electrodes 5a and 5b can be ensured with respect to the heat generating layer 13 of the film 1, and the contact between the heat generating layer and the power supply electrode is stabilized.

<Comparison Evaluation of Fixing Device 107>
In order to confirm the operation of the fixing device 107 of this example, a comparative evaluation was performed using the fixing device of Comparative Example 1, paying attention to the presence or absence of abnormal discharge and damage to the film 1.

  Table 2 shows the comparative evaluation results. The evaluation method is the same as in Example 1.

  In Example 2 (this example), the film 1 was not damaged and abnormal discharge was not generated.

  In the present embodiment, power feeding areas F1 and F2 are arranged in the nip areas N1 and N2. That is, the contact between the heat generating layer 13 of the film 1 and the feeding electrodes 5a and 5b is stabilized, and the generation of voids between them can be suppressed. As a result, the occurrence of abnormal discharge between the feeding electrodes 5a and 5b and the film 1 was suppressed, and as a result, film breakage could be suppressed.

  Since Comparative Example 1 is as described above, the description is omitted.

  As described above, also in the fixing device 107 according to the second embodiment, the power feeding regions F1 and F2 are arranged in the nip regions N1 and N2 as in the first embodiment. Therefore, the same effect as that of the fixing device 107 according to the first embodiment can be obtained.

[Example 3]
Another example of the fixing device 107 will be described. In the present embodiment, only a configuration different from the fixing device 107 of the first embodiment will be described.

  FIG. 9 is a cross-sectional view showing a schematic configuration of the fixing device 107 of this embodiment. FIG. 10 is a diagram when the fixing device 107 is viewed from the upstream side in the conveyance direction of the paper P. FIG.

  The fixing device 107 according to the present exemplary embodiment includes a pair of holders 22 as support members disposed at positions different from the holder 2 inside the film 1 and a pair of slides as slide members supported by the pair of holders. Moving plates 25a and 25b. Further, the fixing device 107 has a pair of auxiliary pressure rollers 23 as auxiliary pressure members disposed on the surface side of the film 1 so as to face the pair of holders 22.

  The pair of heat-resistant resin holders 22 are arranged inside the both end portions of the film 1 in the longitudinal direction perpendicular to the transport direction of the paper P. Regarding the holder 22, the length in the longitudinal direction orthogonal to the transport direction of the paper P is 5 mm, the length in the transport direction of the paper P is 2 mm, and the thickness is 1 mm. The material of the holder 22 is a liquid crystal polymer. In the conveyance direction of the paper P, a concave portion 22a having a depth of 1 mm is provided in the center of the arc-shaped surface of each holder 22 on the auxiliary pressure roller 23 side.

  The pair of power supply electrodes 25a and 25b are each formed in a flat plate shape, and are fitted in the recess 22a of the holder 22 (see FIG. 11D) and fixedly arranged. The material of the power supply electrodes 25a and 25b is an aluminum plate. Regarding the power supply electrodes 25a and 25b, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 5 mm. The dimension of the conveyance direction of the paper P is 2 mm. The thickness is 1 mm.

  A stay 26 having a U-shaped cross section as a pressure member is disposed on the flat surface of each holder 22 opposite to the pressure assisting roller 23. The material of the stay 26 is gin coat steel. In the longitudinal direction perpendicular to the transport direction of the paper P, both ends of the stay 26 are supported by the frames FL and FR.

  The pair of auxiliary pressure rollers 23 has a metal core 233 having an outer diameter of 2 mm. An elastic layer 232 made of silicone rubber having a thickness of 2 mm is provided on the outer periphery of the core metal 233, and a release layer 233 made of PFA having a thickness of 30 μm is provided on the outer periphery of the elastic layer. The pair of auxiliary pressure rollers 23 can be elastically deformed in the radial direction of the auxiliary pressure roller by the elastic layer 232. The outer diameter of the auxiliary pressure roller 23 is 6 mm.

  In the longitudinal direction perpendicular to the transport direction of the paper P, the lengths of the elastic layer 232 and the release layer 233 of the auxiliary pressure roller 23 are 15 mm. In the longitudinal direction perpendicular to the conveyance direction of the paper P, both ends of the core metal 233 of the auxiliary pressure roller 23 are rotatably supported by the frames FL and FR of the fixing device 107 via bearings 28L and 28R.

  A sliding plate 24 is fitted into the recess 2 a of the holder 2 and is fixedly arranged. The material of the sliding plate 24 is a glass plate. Regarding the sliding plate 24, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P is 250 mm. The dimension in the conveyance direction of the paper P is 3 mm. The thickness is 1 mm.

<Feeding opposing areas O3 and O4 and feeding areas F3 and F4>
With reference to FIG. 11, the power supply facing regions O3 and O4 and the power supply regions F3 and F4 of the fixing device 107 will be described.

  11A shows the film 1, the pressure roller 3, the auxiliary pressure roller 23, and the power supply cable 8. FIG. 11B shows the power supply electrodes 25a and 25b, the power supply areas F3 and F4, and the power supply counter area O3. , O4 is a diagram for explaining. 11, (c) is a sectional view taken along line A5-A5 of (a), (d) is a sectional view of the holder 22 on the left side, and a plan view of the holder on the right side.

  With respect to the longitudinal direction perpendicular to the transport direction of the paper P, both ends of the stay 26 are pressurized in the vertical direction perpendicular to the generatrix direction of the film 1 by pressure springs 27L and 27R (see FIG. 10). The stay 26 uniformly presses the holder 22 in the longitudinal direction perpendicular to the transport direction of the paper P by the pressure of the pressure springs 27L and 27R. As a result, the holder 22 presses the power supply electrodes 25 a and 25 b against the inner surface of the heat generating layer 13 of the film 1 and presses the outer peripheral surface (surface) of the film against the outer peripheral surface (surface) of each auxiliary pressure roller 23. The pressing force of the surface of the film 1 against the surface of the auxiliary pressure roller 3 is 8N.

  At this time, the auxiliary pressure roller 23 faces the power supply electrodes 25a and 25b with the film 1 in the longitudinal direction perpendicular to the transport direction of the paper P. Since the power supply electrodes 25a and 25b are arranged at positions where the elastic deformation of the auxiliary pressure roller 23 is maximized in the conveyance direction of the paper P, it is possible to increase the pressing force to each power supply electrode. Therefore, the power feeding electrodes 25 a and 25 b can be stably brought into contact with the heat generating layer 13 of the film 1. As a result, feed opposing regions O3 and O4 and feed regions F3 and F4 shown in FIGS. 11B and 11C are formed.

  Here, the power feeding facing areas O3 and O4 are areas where the surface of the film 1 and the surface of the auxiliary pressure roller 23 are in contact with each other and the surface of the film and the auxiliary pressure roller are pressed by the pressure springs 27L and 27R. is there. The power feeding regions F3 and F4 are regions where the power feeding electrodes 25a and 25b and the heat generating layer 13 of the film 1 are in contact with each other.

  In FIGS. 11B and 11C, the power feeding facing area in the longitudinal direction orthogonal to the transport direction of the paper P is denoted by O3, and the power feeding facing area in the transport direction of the paper P is denoted by O4. . 3B and 3C, a power feeding area in the longitudinal direction orthogonal to the transport direction of the paper P is denoted by F3, and a power feeding area in the transport direction of the paper P is denoted by F4.

  The length of the power feeding facing region O3 is 15 mm, and the length of the power feeding facing region O4 is 4 mm. The length of the power feeding area F3 is 5 mm, and the length of the power feeding area F4 is 2 mm. Since O3> F3 and O4> F4 in the longitudinal direction orthogonal to the transport direction of the paper P and the transport direction of the paper, the power feeding regions F3 and F4 are contained in the power feeding facing regions O3 and O4. That is, the power feeding regions F3 and F4 are arranged only in the power feeding facing regions O3 and O4 (inside the power feeding facing regions O3 and O4). Therefore, pressurization of the power feeding electrodes 25a and 25b can be ensured with respect to the heat generating layer 13 of the film 1, and the contact between the heat generating layer and the power feeding electrode is stabilized.

<Heat fixing processing operation>
The driving force of the motor M (see FIG. 10) is transmitted to the cored bar 33 of the pressure roller 3 through the gear G, whereby the pressure roller rotates in the direction of the arrow shown in FIG. The film 1 rotates in the direction of the arrow shown in FIG. 9 following the rotation of the pressure roller 3 while the film inner surface is in sliding contact with the feeding electrodes 25a and 25b. The pressure auxiliary roller 23 follows the rotation of the film 1 and rotates in the direction of the arrow shown in FIG.

  When power is supplied from the AC power supply V to the heat generating layer 13 of the film 1 via the power supply electrodes 25a and 25b and the power supply cable 8, the heat generating layer generates heat and the film rapidly rises in temperature. The temperature control unit controls the amount of power supplied to the heat generating layer 13 so that the temperature detected by the temperature detecting member 7 is maintained at a predetermined fixing temperature (target temperature).

  The paper P carrying the unfixed toner image T is introduced into the nip areas N1 and N2. The sheet P is heated by the heat of the film 1 while being conveyed in the nip areas N1 and N2. As a result, the toner image T on the paper is fixed on the paper.

<Comparison Evaluation of Fixing Device 107>
In order to confirm the operation of the fixing device 107 of this example, a comparative evaluation was performed using the fixing device of Comparative Example 3 and the fixing device of Comparative Example 4 with a focus on the presence or absence of abnormal discharge and film breakage.

(Comparative Example 3)
FIG. 12 shows a fixing device of Comparative Example 3. 12A shows the film 1, the pressure roller 3, the auxiliary pressure roller 23, and the power supply cable 8. FIG. 12B shows the power supply electrodes 25a and 25b, the power supply regions F3 and F4, and the power supply counter region O3. , O4 is a diagram for explaining. (C) is a sectional view taken along line A6-A6 of (a), (d) is a sectional view of the holder 22 on the left side, and a plan view of the holder on the right side.

  Unlike the configuration of the present example, the comparative example 3 has a length of the elastic layer 232 in the longitudinal direction perpendicular to the transport direction of the paper P and the release layer 231 with respect to the auxiliary pressure roller 23 being 5 mm. Regarding the power supply electrodes 25a and 25b, the dimension in the longitudinal direction perpendicular to the transport direction of the paper P was 15 mm, the dimension in the transport direction of the paper P was 2 mm, and the thickness was 1 mm. Regarding the holder 22, the dimension in the longitudinal direction orthogonal to the transport direction of the paper P was set to 15 mm.

  At this time, the lengths of O3, O4, F3, and F4 are 5 mm, 4 mm, 15 mm, and 2 mm, respectively.

  As shown in FIG. 12B, in the longitudinal direction orthogonal to the transport direction of the paper P, the power supply region F3 protrudes from the power supply opposing region O3 because F3> O3. On the other hand, as shown in FIG. 12C, in the transport direction of the paper P, the power feeding area F4 is within the power feeding facing area O4 because O4> F4. As shown in FIG. 12B, in the power feeding region F3, a region where the power feeding electrodes 25a and 25b are not pressed against the inner surface of the film 1 in the longitudinal direction perpendicular to the transport direction of the paper P (non-pressurizing). Area) has occurred. Therefore, in the longitudinal direction orthogonal to the transport direction of the paper P, the contact between the heat generating layer 13 of the film 1 and the power feeding electrodes 5a and 5b becomes unstable.

(Comparative Example 4)
FIG. 13 shows a fixing device of Comparative Example 4. 13A is a diagram showing the film 1, the pressure roller 3, the auxiliary pressure roller 23, and the power supply cable 8. FIG. 13B is a diagram showing power supply electrodes 25a and 25b, power supply regions F3 and F4, and a power supply counter region O3. , O4 is a diagram for explaining. (C) is a sectional view taken along line A7-A7 in (a), (d) is a sectional view of the holder 22 on the left side, and a plan view of the holder on the right side.

  In Comparative Example 4, unlike the configuration of this example, the outer diameter of the auxiliary pressure roller 23 was 4 mm. Regarding the power supply electrodes 25a and 25b, the dimension in the transport direction of the paper P was 5 mm, the dimension in the transport direction of the paper P was 5 mm, and the thickness was 1 mm.

  At this time, the lengths of O3, O4, F3, and F4 are 15 mm, 5 mm, 5 mm, and 4 mm, respectively.

  As shown in FIG. 13B, in the longitudinal direction orthogonal to the transport direction of the paper P, the power feeding area F3 is within the power feeding facing area O3 because O3> F3. On the other hand, as shown in FIG. 12C, in the transport direction of the paper P, the power supply area F4 protrudes from the power supply facing area O4 because F4> O4. As shown in FIG. 12C, in the power feeding area F4, an area where the power feeding electrodes 25a and 25b are not pressed against the inner surface of the film 1 (non-pressurizing area) occurs in the feeding direction of the paper P. ing. Therefore, in the conveyance direction of the paper P, the contact between the heat generating layer 13 of the film 1 and the power feeding electrodes 5a and 5b becomes unstable.

  Table 3 shows the comparative evaluation results. The evaluation method is the same as in Example 1.

  In Example 3 (this example), the film 1 was not damaged and no abnormal discharge occurred.

  In the present embodiment, power feeding areas F3 and F4 are arranged in the power feeding facing areas O3 and O4. That is, the contact between the heat generating layer 13 of the film 1 and the feeding electrodes 25a and 25b is stabilized, and the generation of voids between them can be suppressed. Thereby, abnormal electric discharge generation | occurrence | production between electric power feeding electrode 25a, 25b and the film 1 was suppressed, As a result, the film breakage was able to be suppressed.

  In Comparative Example 3, film 1 was damaged and abnormal discharge occurred.

  In Comparative Example 3, the power feeding area F3 extends outside the power feeding facing area O3. The area that protrudes from the power supply facing area O <b> 3 is not pressurized by the pressure auxiliary roller 23. In the region protruding from the power supply facing region O3, the contact between the heat generating layer 13 of the film 1 and the power supply electrodes 25a and 25b is unstable, and a gap may be generated between them. In addition, there is rarely a moment when a current path is generated between the gaps due to the sliding grease or film scraping powder adhering to the surfaces of the power supply electrodes 25a and 25b. Thereby, it is considered that abnormal discharge occurs between the power supply electrodes 25a and 25b and the film 1, and the film is damaged.

  In Comparative Example 4, as in Comparative Example 1, the fixing film 1 was damaged and abnormal discharge occurred.

  In Comparative Example 4, the power feeding region F4 extends outside the power feeding facing region O4. The area that protrudes from the power supply facing area O4 is not pressurized by the auxiliary pressure roller 23. In the region protruding from the power supply facing region O4, the contact between the heat generating layer 13 of the film 1 and the power supply electrodes 25a and 25b is unstable, and a gap may be generated between them. In addition, there is rarely a moment when a current path is generated between the gaps due to the sliding grease or film scraping powder adhering to the surfaces of the power supply electrodes 25a and 25b. Thereby, it is considered that abnormal discharge occurs between the power supply electrodes 25a and 25b and the film 1, and the film is damaged.

  As described above, in the fixing device 107 of this embodiment, the power feeding regions F3 and F4 are arranged in the power feeding facing regions O3 and O4. Therefore, the conduction path between the power supply electrodes 25a and 25b and the heat generating layer 13 of the film 1 is stabilized, the generation of a gap between the power supply electrode and the film can be suppressed, and the occurrence of abnormal discharge between the power supply electrode and the film can be suppressed. Therefore, the same effect as that of the fixing device 107 according to the first embodiment can be obtained.

[Other examples]
In the fixing device 107 according to the first to third embodiments, the film 1 has the elastic layer 13. Needless to say, the same effect can be obtained even with a film without the elastic layer. Further, the same effect can be obtained even in a configuration in which a metal paste (for example, silver) is applied to the inner circumferential surfaces of both ends of the film 1 in the longitudinal direction perpendicular to the conveyance direction of the paper P to supply power to the power supply electrodes 5a and 5b. Needless to say. That is, the same effect can be obtained regardless of the layer structure of the film 1.

  The heating device according to the present invention is not limited to use as a fixing device as in the first to third embodiments. It can also be effectively used as an image modifying device for modifying the glossiness of an image once fixed on the paper P (fixed image) or an assumed image (semi-fixed image).

1 film, 3 pressure roller, 5a, 5b feeding electrode, 13 heating layer,
23 pressure auxiliary roller, 25a, 25b feeding electrode, F1, F2 feeding area,
F3, F4 feeding area, N1, N2 nip area, O3, O4 feeding area

Claims (2)

A heating rotating member having a heat generating layer that generates heat when energized;
A power supply member that forms a power supply region in contact with the heat generating layer;
A pressure rotary member that contacts the heating rotary member to form a nip region;
A heating device for heating an image carried by the recording material in the nip region,
The heating device, wherein the power feeding region is disposed only inside the nip region. A heating rotating member having a heat generating layer that generates heat when energized;
A power supply member that forms a power supply region in contact with the heat generating layer;
A pressure rotary member that contacts the heating rotary member to form a nip region;
A pressurizing auxiliary member that is in contact with the heating rotary member to form a power feeding facing region;
A heating device for heating an image carried by the recording material in the nip region,
The heating device, wherein the power feeding region is disposed only inside the power feeding opposing region.