JP2015040973A - Fixing device, heating device, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fixing device that has suppressed deformation of a heating member due to thermal expansion.SOLUTION: A fixing unit 60 has a fixing belt 61 that fixes a toner image to a sheet P, a pressure roll 62 that is brought into pressure contact with the outer peripheral surface of the fixing belt 61 to form a nip part N through which the sheet P holding an unfixed toner image passes, and a heating part in which sides are continuously connected to each other to form an obtuse angle or shapes configured of an arc are further connected to each other to form wiring linear in an axial direction, and further includes a heating member that heats the fixing belt 61.

Description

  The present invention relates to a fixing device, a heating device, and an image forming apparatus.

In Patent Document 1, a sheet heating element is formed by forming a heating pattern in which a resistance heating element that generates heat when energized forms a surface having a certain shape as a whole, and is formed on one surface in the thickness direction of an insulating layer. The resistance heating element extends in a direction substantially perpendicular to the longitudinal direction of the insulating layer, and each of the plurality of linear portions formed on one surface of the insulating layer in a substantially parallel state, and adjacent linear portions A sheet-like heat generating element including a low volume resistance portion formed on one surface of the insulating layer by connecting the end portions in the extending direction so as to form one line extending in the longitudinal direction of the insulating layer The body is listed.
Further, in Patent Document 2, a planar resistance heating element is fixedly arranged on the back surface of a semi-cylindrical heating panel having a curved surface with an arc-shaped cross section, and energization control is performed based on a temperature detected by a temperature sensor. The fixing belt moves on the surface of the heating panel and is heated to a temperature suitable for the fixing process, and the resistance heating element is configured by arranging heating lines in parallel in a plane shape, and the parallel portions of the heating lines arranged in parallel are fixed. There is described a fixing device that is inclined by a certain angle with respect to the width direction of the belt and forms a parallelogram heat generation pattern serving as a heat generation region.

JP 2009-259714 A JP 2006-215056 A

  It is desirable that the heating member for heating the fixing member for fixing the toner image is less likely to be deformed due to thermal expansion.

According to the first aspect of the present invention, there is provided a fixing member that fixes a toner image on a recording material, and a fixing pressure unit that is pressed against the outer peripheral surface of the fixing member and through which the recording material that holds an unfixed toner image passes. It has a heating part in which a wiring extending in the axial direction is formed by connecting the pressurizing member to be formed continuously so that the side part forms an obtuse angle, or by further connecting a shape constituted by an arc. And a heating member that heats the fixing member.
The invention according to claim 2 is the fixing device according to claim 1, wherein the side portions constituting the shape are of equal length.
A third aspect of the present invention is the fixing device according to the first or second aspect, wherein the wiring is arranged in a plurality of rows in the rotation direction of the fixing member.
The invention described in claim 4 is the fixing device according to any one of claims 1 to 3, wherein the shape is a part of a regular hexagon.
In the invention according to claim 5, the heating part in which the wiring extending in the axial direction is formed by connecting the side parts continuously so as to form an obtuse angle or by further connecting the shape constituted by the circular arc. And a heating device that heats a fixing member that fixes a toner image on a recording material, and a fixing portion that fixes the heating member along an inner peripheral surface of the fixing member.
According to a sixth aspect of the present invention, a toner image forming portion that forms a toner image, a transfer portion that transfers the toner image to a recording material, a fixing member that fixes the toner image, and an outer peripheral surface of the fixing member are pressed against each other. The fixing member has a heating part in which a wiring extending in the axial direction is formed by connecting the pressing member continuously so that the side part forms an obtuse angle or a shape constituted by an arc is further connected. An image forming apparatus including a fixing unit including a heating member that heats the image forming apparatus.

According to the first and second aspects of the invention, it is possible to provide a fixing device in which the heating member is less likely to be deformed due to thermal expansion.
According to the invention of claim 3, it becomes easier to heat the fixing member.
According to invention of Claim 4, the density of wiring can be improved.
According to the fifth aspect of the present invention, it is possible to provide a heating device that can heat the fixing member so as to reduce the unevenness of the temperature distribution.
According to the invention of claim 6, it is possible to provide an image forming apparatus capable of forming an image with less gloss unevenness.

1 is a diagram illustrating a configuration example of an image forming apparatus to which a fixing device according to an exemplary embodiment is applied. FIG. 2 is a front view illustrating a configuration of a fixing unit of the present embodiment. FIG. 3 is a sectional view of the fixing device taken along the line III-III in FIG. 2. FIG. 3 is a cross-sectional layer configuration diagram of a fixing belt. (A)-(b) is a figure which shows the structure of the heater unit of this Embodiment. (A)-(b) is the figure explaining the structure of the heater. (A)-(c) is the example explaining the pattern of the heat generating layer. (A)-(b) is the 1st example explaining the pattern of the conventional heat_generation | fever layer. (A)-(b) is the 2nd example explaining the pattern of the conventional heat_generation | fever layer. (A)-(b) is a figure explaining the example at the time of using another basic pattern. (A)-(b) is the figure explaining the example at the time of using another basic pattern. (A)-(b) is the figure explaining the example at the time of using another basic pattern.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
<Description of Image Forming Apparatus>
FIG. 1 is a diagram illustrating a configuration example of an image forming apparatus to which the fixing device of the present embodiment is applied. An image forming apparatus 1 shown in FIG. 1 is a so-called tandem color printer, and includes an image forming unit 10 that forms an image based on image data and a control unit 31 that controls the operation of the entire image forming apparatus 1. Further, for example, a communication unit 32 that receives image data by communicating with a personal computer (PC) 3 or an image reading device (scanner) 4, and a predetermined image for the image data received by the communication unit 32. An image processing unit 33 that performs processing is provided.

The image forming unit 10 is arranged in parallel at a predetermined interval, and includes four image forming units 11Y, 11M, 11C, and 11K (also collectively referred to as “image forming unit 11”). Each image forming unit 11 is an example of a toner image forming unit that forms a toner image. The image forming unit 11 is charged by a photosensitive drum 12 that forms an electrostatic latent image and holds a toner image, a charger 13 that charges the surface of the photosensitive drum 12 at a predetermined potential, and a charger 13. An LED (Light Emitting Diode) print head 14 that exposes the photosensitive drum 12 based on each color image data, a developing device 15 that develops an electrostatic latent image formed on the photosensitive drum 12, and the surface of the photosensitive drum 12 after transfer A drum cleaner 16 is provided.
Each of the image forming units 11 is configured in substantially the same manner except for the toner stored in the developing device 15, and each forms a toner image of yellow (Y), magenta (M), cyan (C), and black (K). To do.

  The image forming unit 10 also receives the intermediate transfer belt 20 onto which the color toner images formed on the photosensitive drums 12 of the image forming units 11 are transferred, and the color toner images formed on the image forming units 11. A primary transfer roll 21 that sequentially transfers (primary transfer) to the intermediate transfer belt 20 is provided. Further, a secondary transfer roll 22 that batch-transfers (secondary transfer) each color toner image transferred and superimposed on the intermediate transfer belt 20 onto a sheet P that is a recording material (recording paper), and each color toner that is secondarily transferred. A fixing unit 60 as an example of a fixing unit (fixing device) that fixes an image on the paper P is provided. In the image forming apparatus 1 of the present embodiment, the intermediate transfer belt 20, the primary transfer roll 21, and the secondary transfer roll 22 constitute a transfer unit that fixes the toner image onto the paper P.

  In the image forming apparatus 1 of the present embodiment, under the operation control by the control unit 31, image forming processing is performed by the following process. That is, the image data from the PC 3 or the scanner 4 is received by the communication unit 32, subjected to predetermined image processing by the image processing unit 33, and then sent to each image forming unit 11 as image data for each color. It is done. For example, in the image forming unit 11K that forms a black (K) toner image, the photosensitive drum 12 is charged at a predetermined potential by the charger 13 while rotating in the direction of arrow A, and is transmitted from the image processing unit 33. The LED print head 14 scans and exposes the photosensitive drum 12 based on the K color image data. As a result, an electrostatic latent image relating to the K color image is formed on the photosensitive drum 12. The K-color electrostatic latent image formed on the photosensitive drum 12 is developed by the developing unit 15, and a K-color toner image is formed on the photosensitive drum 12. Similarly, yellow (Y), magenta (M), and cyan (C) toner images are formed in the image forming units 11Y, 11M, and 11C, respectively.

  Each color toner image formed on the photosensitive drum 12 of each image forming unit 11 is sequentially electrostatically transferred (primary transfer) onto the intermediate transfer belt 20 that moves in the direction of arrow B by the primary transfer roll 21, and each color toner is superimposed. A superimposed toner image is formed. The superimposed toner image on the intermediate transfer belt 20 is conveyed to a region (secondary transfer portion T) where the secondary transfer roll 22 is disposed as the intermediate transfer belt 20 moves. When the superimposed toner image is conveyed to the secondary transfer unit T, the paper P is supplied from the paper holding unit 40 to the secondary transfer unit T in accordance with the timing. The superimposed toner image is collectively electrostatically transferred (secondary transfer) onto the conveyed paper P by the transfer electric field formed by the secondary transfer roll 22 in the secondary transfer portion T.

Thereafter, the sheet P on which the superimposed toner image is electrostatically transferred is conveyed to the fixing unit 60. The toner image on the paper P conveyed to the fixing unit 60 receives heat and pressure by the fixing unit 60 and is fixed on the paper P. Then, the paper P on which the fixed image is formed is conveyed to a paper stacking unit 45 provided in the discharge unit of the image forming apparatus 1.
On the other hand, the toner (primary transfer residual toner) adhering to the photosensitive drum 12 after the primary transfer and the toner (secondary transfer residual toner) adhering to the intermediate transfer belt 20 after the secondary transfer are respectively drum cleaner 16. , And the belt cleaner 25.
In this way, the image forming process in the image forming apparatus 1 is repeatedly executed for the number of printed sheets.

<Description of fixing unit configuration>
Next, the fixing unit 60 of this embodiment will be described.
2 and 3 are views showing a configuration of the fixing unit 60 of the present embodiment, FIG. 2 is a front view, and FIG. 3 is a sectional view taken along line III-III in FIG.
First, as shown in FIG. 3 which is a cross-sectional view, the fixing unit 60 includes a heater unit 80 which is an example of a heating device, and a fixing belt 61 which fixes the toner image on the paper P by being heated by the heater unit 80. The pressure roll 62 is disposed so as to face the fixing belt 61, and the pressure pad 63 is pressed from the pressure roll 62 via the fixing belt 61.
Further, the fixing unit 60 includes a frame 64 that supports constituent members such as the pressing pad 63, a temperature sensor 65 that measures the temperature of the fixing belt 61 in contact with the inner peripheral surface of the fixing belt 61, and the fixing belt 61. A separation assisting member 70 that assists in the separation of the paper P is provided.

<Description of fixing belt>
The fixing belt 61 functions as a fixing member that fixes the toner image on the paper P. The fixing belt 61 is composed of an endless belt member whose original shape is a cylindrical shape, and has a diameter of 30 mm and a width direction length of 300 mm when the original shape (cylindrical shape) is used, for example. Also, as shown in FIG. 4 (cross-sectional layer configuration diagram of the fixing belt 61), the fixing belt 61 is a belt having a structure including a base material layer 611 and a release layer 612 coated on the base material layer 611. It is a member.

The base material layer 611 is composed of a heat-resistant sheet-like member that forms the mechanical strength of the entire fixing belt 61.
As the base material layer 611, for example, a sheet made of polyimide resin and having a thickness of 60 μm to 200 μm is used. In order to make the temperature distribution of the fixing belt 61 more uniform, a heat conductive filler made of aluminum or the like may be included in the polyimide resin sheet.

  Since the release layer 612 is in direct contact with the unfixed toner image held on the paper P, a material having a high release property is used. For example, PFA (tetrafluoroethylene perfluoroalkyl vinyl ether polymer), PTFE (polytetrafluoroethylene), silicone copolymer, or a composite layer thereof is used. If the thickness of the release layer 612 is too thin, the wear resistance is not sufficient, and the life of the fixing belt 61 is shortened. On the other hand, if it is too thick, the heat capacity of the fixing belt 61 becomes too large and the warm-up time becomes long. Therefore, the thickness of the release layer 612 is preferably 1 μm to 50 μm in consideration of the balance between wear resistance and heat capacity.

<Description of Fixing Belt Drive Mechanism>
Next, a driving mechanism for the fixing belt 61 will be described.
As shown in FIG. 2 which is a front view, the fixing belt 61 is rotated in the circumferential direction while maintaining the cross-sectional shape of both ends of the fixing belt 61 in a circular shape at both ends in the axial direction of the frame 64 (see FIG. 3). An end cap member 67 to be driven is fixed. The fixing belt 61 directly receives the rotational driving force from both ends via the end cap member 67, and rotates and moves in the direction of arrow C in FIG. 3 at a process speed of 140 mm / s, for example.
As a material constituting the end cap member 67, so-called engineering plastics having high mechanical strength and heat resistance are used. For example, phenol resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK resin, PES resin, PPS resin, LCP resin and the like are suitable.

As shown in FIG. 2, in the fixing unit 60, the rotational driving force from the drive motor 90 is transmitted to the shaft 93 via the transmission gears 91 and 92, and both are transmitted from the transmission gears 94 and 95 coupled to the shaft 93. It is transmitted to the end cap member 67. As a result, a rotational driving force is transmitted from the end cap member 67 to the fixing belt 61, and the end cap member 67 and the fixing belt 61 are integrally rotated.
Thus, the fixing belt 61 rotates by receiving the driving force directly from both ends of the fixing belt 61, so that the fixing belt 61 rotates stably.
The drive mechanism is not limited to this, and the pressure roll 62 is rotated by the drive motor 90 in a state where the pressure roll 62 and the fixing belt 61 form the nip portion N (fixing pressure portion). Accordingly, the fixing belt 61 may be driven.

<Description of pressure roll>
Returning to FIG. 3, the pressure roll 62 is disposed so as to face the fixing belt 61, and rotates in the direction of arrow D in FIG. 3 at a process speed of, for example, 140 mm / s according to the fixing belt 61. Then, a nip portion (fixing pressure portion) N is formed in a state where the fixing belt 61 is sandwiched between the pressure roll 62 and the pressing pad 63, and the paper P holding the unfixed toner image is passed through the nip portion N. Thus, heat and pressure are applied to fix the unfixed toner image on the paper P. That is, the pressure roll 62 functions as a pressure member that presses against the outer peripheral surface of the fixing belt 61 and forms a nip portion N through which the paper P holding an unfixed toner image passes.
The pressure roll 62 includes a solid stainless steel or aluminum core (columnar core) 621 having a diameter of 18 mm, for example, and a heat-resistant elastic body such as a silicone sponge having a thickness of 5 mm coated on the outer peripheral surface of the core 621. The layer 622 is further laminated with a release layer 623 made of a heat-resistant resin coating such as PFA containing carbon having a thickness of 50 μm or a heat-resistant rubber coating. Then, the pressing pad 63 is pressed through the fixing belt 61 with a load of 25 kgf, for example, by a pressing spring 68 (see FIG. 2).

<Description of pressing pad>
For the pressing pad 63, for example, silicone rubber, fluoro rubber, or so-called engineering plastics having high mechanical strength and heat resistance is used. For example, rigid bodies such as phenol resin, polyimide resin, polyamide resin, polyamideimide resin, PEEK (poly ether ether ketone) resin, PES (poly ether sulfone) resin, PPS (poly phenylene sulfide) resin, LCP resin (liquid crystal polymer) Is a block member having a substantially arc-shaped cross section, and is supported by a frame 64 inside the fixing belt 61. The pressure roll 62 is fixedly arranged over the entire axial direction in the region where the fixing belt 61 is pressed. The pressing pad 63 is installed so as to press the pressure roll 62 uniformly with a predetermined load (for example, average 10 kgf) over a predetermined width region via the fixing belt 61, and the nip portion. N is formed.

<Explanation of temperature sensor>
The temperature sensor 65 is, for example, a thermistor-type temperature sensor, and includes a temperature detection unit having a thermistor that is a material whose resistance value changes with a change in temperature.

  As the thermistor used in the temperature detector, for example, an NTC (Negative Temperature Coefficient) thermistor whose resistance decreases as temperature rises, a PTC (Positive Temperature Coefficient) thermistor whose resistance increases as temperature rises, temperature Various thermistors, such as a CTR (Critical Temperature Resistor) thermistor, whose resistance decreases with increasing temperature but has good sensitivity in a specific temperature range, can be used.

  Information on the temperature detected by the temperature sensor 65 is sent to the control unit 31, for example. The control unit 31 controls the heater unit 80 based on the temperature information so that the temperature of the fixing belt 61 falls within a predetermined range.

<Description of heater unit configuration>
Next, the heater unit 80 of the present embodiment will be described.
FIGS. 5A and 5B are diagrams showing the configuration of the heater unit 80 of the present embodiment.
Here, FIG. 5A is a perspective view of the heater unit 80. FIG. 5B is a view of the heater unit 80 as viewed from the Vb direction in FIG.
The illustrated heater unit 80 includes a heater 81 that is a heat generation source, a guide 82 that defines the shape of the heater 81 in an arch shape, an attachment portion 83 to which the heater 81 and the guide 82 are attached, and the heater 81 is fixed to the attachment portion 83. And a pressing member 85 for pressing the heater unit 80 against the fixing belt 61.

In the present embodiment, the heater 81 functions as an example of a heating member that heats the fixing belt 61 by contacting the inner peripheral surface of the fixing belt 61 (see FIG. 3).
FIGS. 6A and 6B are diagrams illustrating the structure of the heater 81.
The heater 81 is a so-called film heater and has flexibility. In an actual use state, as shown in FIG. 5, in order to make contact with the inner peripheral surface of the fixing belt 61, it is bent in an arc shape along the inner peripheral surface of the fixing belt 61 and attached in an arch shape. However, in order to make the explanation easy to understand, FIGS. 6A to 6B show the planar heater 81 before being bent into an arc shape.
Here, FIG. 6A is a perspective view of the heater 81. FIG. 6B is a cross-sectional view of the heater 81 taken along VIb-VIb.

  As illustrated, the heater 81 has a structure in which a heat generating layer 811 is sandwiched between insulating layers 812. The heat generating layer 811 includes a heat diffusion layer 813 on the side in contact with the fixing belt 61.

In the present embodiment, the heat generation layer 811 functions as an example of a heating unit in which a wiring draws a predetermined pattern.
The heat generating layer 811 is made of a conductive heat generating material and generates heat when energized. In the present embodiment, the heat generating layer 811 is made of, for example, a stainless foil having a thickness of 30 μm. As will be described later in detail, heat is generated more uniformly by drawing a predetermined pattern.

The insulating layer 812 is a layer for insulating the heat generating layer 811 and protecting the heat generating layer 811 from being bent or the like. In this embodiment, the insulating layer 812 has a two-layer structure of an insulating layer 812a and an insulating layer 812b. Then, the heat generation layer 811 is sandwiched between the insulating layer 812a and the insulating layer 812b, and the heat generation layer 811 is included in the insulating layer 812 by performing thermocompression bonding. Therefore, in this case, the insulating layer 812a and the insulating layer 812b are bonded and integrated.
The insulating layers 812a and 812b need to be made of a material having insulating properties and excellent heat resistance. In this embodiment, for example, thermosetting polyimide having a thickness of 25 μm to 50 μm is used as the insulating layer 812a. As the insulating layer 812b, for example, thermoplastic polyimide having a thickness of 25 μm to 50 μm is used.

The heat diffusion layer 813 is a layer for diffusing heat generated from the heat generation layer 811 and transferring the heat to the fixing belt 61. The fixing belt 61 is heated more uniformly by the heat diffusion layer 813, and uneven temperature distribution in the fixing belt 61 is suppressed.
The thermal diffusion layer 813 needs to be made of a material having excellent heat conductivity and excellent heat resistance. In the embodiment, for example, a stainless foil having a thickness of 30 μm to 50 μm is used as the thermal diffusion layer 813.
The thermal diffusion layer 813 is bonded to the insulating layer 812b. Actually, when the heat-generating layer 811 is sandwiched between the insulating layer 812a and the insulating layer 812b and thermocompression bonding is performed, the heat diffusion layer 813 and the insulating layer 812b are bonded together.

Returning to FIG. 5, the guides 82 are members that are respectively disposed at both ends in the axial direction of the heater 81 (ends on the short side of the heater 81) and define the shape of the heater 81 in an arch shape. That is, the heater 81 is bent along the guide 82 at both ends in the axial direction, and the shape of the heater 81 is defined by the shape of the portion in contact with the guide 82. Since the surface where the guide 82 comes into contact with the heater 81 is formed in accordance with the shape of the inner peripheral surface of the fixing belt 61, the heater 81 can maintain better contact with the fixing belt 61, and as a result. In addition, it is possible to suppress the occurrence of uneven temperature distribution in the fixing belt 61.
The guide 82 is required to have excellent heat resistance and excellent workability. In the present embodiment, for example, polyphenylene sulfide (PPS) resin is used as a material for forming the guide 82.

  The guide 82 is attached to the attachment portion 83. In addition, the heater 81 is rigidly fixed to the attachment portion 83 by bolts 84 at both ends in the rotational direction of the fixing belt 61 (ends on the long side of the heater 81). The heater 81 is rigidly fixed to the attachment portion 83 by bolts 84 at, for example, four places on one side, for a total of eight places.

  In other words, the heater 81 is arched by the guide 82 and rigidly fixed to the mounting portion 83 by the bolt 84. As a result, the heater 81 is shaped along the inner peripheral surface of the fixing belt 61, and deformation of the heater 81 due to thermal expansion can be suppressed even when the heater 81 generates heat. Therefore, the guide 82 and the attachment portion 83 function as a fixing portion that fixes the heater 81 along the inner peripheral surface of the fixing belt 61 that fixes the toner image on the paper P.

  Further, in the present embodiment, the heat generation layer 811 of the heater 81 is not provided at a location where the guide 82 or the attachment portion 83 comes into contact. That is, the heat generating layer 811 is provided in a region between the guides 82 provided at the end portion on the short side of the heater 81 in the axial direction. Further, the heat generating layer 811 is provided in the region between the attachment portion 83 and the rigidly fixed portion at the end portion on the long side of the heater 81 in the rotation direction of the fixing belt 61. Therefore, in the region where the heat generation layer 811 of the heater 81 is provided, the heater 81 is not in contact with other members other than the fixing belt 61. That is, for example, in FIG. 5, the upper surface of the heater 81 is in contact with the fixing belt 61, but the lower surface of the heater 81 is not in contact with other members in the region where the heat generating layer 811 is provided. It is in a hollow state. Thereby, heat conduction to other members other than the fixing belt 61 can be suppressed, and further, since the heater 81 is in a film shape, the heat capacity of the heater 81 can be reduced. For this reason, the power of the image forming apparatus 1 (see FIG. 1) is turned on, and the temperature of the fixing belt 61 can be raised more quickly when the fixing unit 60 (see FIG. 1) is started up. As a result, the time (warm-up time) for raising the fixing belt 61 to the fixable temperature is shortened.

  The pressing member 85 is, for example, a coil spring, and a plurality of the pressing members 85 are arranged in the axial direction of the heater unit 80. In the present embodiment, a total of four pressing members 85 are provided, two at each end in the axial direction of the heater unit 80. One end of the pressing member 85 is fixed to the heater unit 80. The other end is in contact with the frame 64 (see FIG. 3). That is, the pressing member 85 is positioned between the frame 64 and the heater unit 80 and presses the heater unit 80 against the fixing belt 61 by the pressing force generated by the pressing member 85. As a result, the heater 81 of the heater unit 80 can maintain contact with the fixing belt 61.

<Description of heat generation layer pattern>
Next, the pattern of the heat generating layer 811 will be described.
FIGS. 7A to 7C are examples illustrating the pattern of the heat generating layer 811.
Here, FIG. 7A is an overall view of the pattern of the heat generating layer 811. FIG. 7B is an enlarged view of a part of the pattern of the heat generating layer 811. Further, FIG. 7C is a diagram for describing a first example of a basic pattern constituting the pattern of the heat generating layer 811.
In the present embodiment, the pattern of the heat generating layer 811 is formed by connecting shapes (basic patterns) as shown in FIG. 7C continuously. The basic pattern is further connected in succession, whereby the pattern of the heat generating layer 811 forms wiring extending linearly in the axial direction (long side direction of the heater 81) as shown in FIG. Further, as shown in FIG. 7A, for example, the wiring is arranged in a plurality of rows in the rotation direction of the fixing belt 61 (the short side direction of the heater 81). In the example shown in FIG. 7A, seven rows are arranged in the rotation direction of the fixing belt 61.

  In the example shown in FIG. 7A, the pattern of the heat generating layer 811 is divided into three systems. The first pattern is a pattern connected to the lead line H1 and the lead line H2. This pattern is connected to wiring lines arranged in the first row from the bottom in the drawing and the first to fifth rows from the bottom in the drawing in the center in the drawing, so-called one-stroke writing from the lead-out line H1 to the lead-out line H2. It has become. The second pattern is connected to the wirings arranged in the second to sixth rows from the lead line H1, and reaches the lead line H3. Further, the third pattern is connected to the wirings arranged in the third to seventh rows from the lead-out line H1, and reaches the lead-out line H4.

In the present embodiment, as shown in FIG. 7C, the basic pattern is a part of a regular hexagon and takes a shape obtained by halving the regular hexagon. Then, these basic patterns are continuously connected to form the pattern shown in FIG.
That is, the basic pattern forming the pattern of the heat generating layer 811 of this embodiment is configured by connecting the sides. And it has the characteristic in connecting continuously so that each side part may make an obtuse angle. In the case of FIGS. 7A to 7C, the angle θ formed by the side portions is 120 °. Moreover, it is preferable that the side part which comprises a basic pattern is substantially equal length.

FIGS. 8A and 8B are a first example illustrating a conventional heat generating layer pattern.
Here, FIG. 8A is an overall view of the pattern of the conventional heat generating layer 911. FIG. 8B is a diagram for explaining a basic pattern of patterns constituting the heat generating layer 911.
As shown in the figure, the conventional heat generating layer 911 uses a part of a parallelogram as a basic pattern.

FIGS. 9A to 9B are a second example illustrating a conventional heat generating layer pattern.
Here, FIG. 9A is an overall view of the pattern of the conventional heat generating layer 911. FIG. 9B is a diagram for explaining a basic pattern of patterns constituting the heat generating layer 911.
As shown in the drawing, the conventional heat generating layer 911 has a basic pattern in a U shape consisting of an arcuate portion and a straight portion.

  8 and 9, the rigidity of the heat generating layer 911 varies depending on the direction. For example, the rigidity differs between the axial direction and the rotation direction of the fixing belt 61. In this case, when the heat generating layer 911 generates heat, the coefficient of thermal expansion differs between the heat generating layer 911 and the insulating layer provided around the heat generating layer 911, and thus the heater 81 (see FIG. 5) is likely to be deformed. For the same reason, a phenomenon in which the heat generating layer 911 is peeled off from the insulating layer is likely to occur. Further, as described above, the heater 81 needs to be bent and attached to the heater unit 80 (see FIG. 5) in an arc shape. However, when the heat generating layer 911 is bent, the heat diffusion layer 813 (see FIG. 5) of the heater 81 is bent for the same reason. (See below) is likely to break.

In the case of the example in FIG. 8, the side portions constituting the basic pattern may be connected at an acute angle. In this case, unevenness of heat generation in the heat generation layer 911 is likely to occur. That is, the resistance is likely to increase at an acute angle portion, so that a difference in the amount of heat generated between the acute angle portion and other portions is likely to occur.
Further, in the case of the example of FIG. 9, the resistance is likely to increase at the arc-shaped portion, so that a difference in the amount of generated heat is easily generated between the arc-shaped portion and the linear portion.

In the present embodiment, for example, as shown in FIG. 7, this phenomenon is suppressed by continuously connecting the relatively short side portions so as to form an obtuse angle. That is, since the basic pattern is a part of a regular hexagon, there is almost no difference in rigidity of the heat generating layer 811 depending on the direction. Therefore, the above-described deformation of the heater 81, the phenomenon that the heat generating layer 811 is peeled off, and the phenomenon that the heat diffusion layer 813 is broken are less likely to occur. Further, since the side portions forming the basic pattern are connected at an obtuse angle, the distribution of heat generation is compared to the example of FIG. 8 connected at an acute angle or the example of FIG. 9 divided into an arcuate portion and a straight portion. Unevenness is unlikely to occur.
In addition, the basic pattern of the present embodiment is further reduced from being uneven in the difference in rigidity of the heat generation layer 811 and the distribution of heat generation due to the above direction by forming the size smaller. In the example of FIG. 7, the width of the portion where the basic pattern is not formed is, for example, 0.3 mm to 0.5 mm.

The basic pattern is not limited to the example shown in FIG.
FIGS. 10A to 10B are diagrams illustrating an example in which another basic pattern is used.
Here, FIG. 10B is a diagram illustrating a second example of the basic pattern constituting the pattern of the heat generating layer 811. FIG. 10A is a diagram illustrating a pattern of the heat generating layer 811 when the basic pattern of FIG. 10B is used.
As shown in FIG. 10B, the basic pattern is also a part of a regular hexagon in this embodiment. These are continuously connected to form the pattern shown in FIG.
As illustrated, the basic pattern in FIG. 10B is different in shape from the basic pattern illustrated in FIG. That is, a pattern is formed by cutting out part of two sides to be connected from a regular hexagon.
When this basic pattern is used, the sides constituting the basic pattern do not have the same length, but the wiring density can be made higher than in the case where the basic pattern is shown in FIG. In this case as well, the angle θ between the sides is 120 °.

FIGS. 11A to 11B are diagrams illustrating an example in which still another basic pattern is used.
Here, FIG. 11B is a diagram illustrating a third example of the basic pattern constituting the pattern of the heat generating layer 811. FIG. 11A is a diagram illustrating a pattern of the heat generating layer 811 when the basic pattern of FIG. 11B is used.
As shown in FIG. 11B, in the present embodiment, the basic pattern is a part of a regular pentagon. In this case, a pattern obtained by cutting out one side of the regular pentagon and a part of two sides connected to the one side from the regular pentagon. These are continuously connected to form the pattern shown in FIG. In the case of FIGS. 11A to 11B, the angle θ between the sides is 108 °.
In this example as well, there is almost no difference in rigidity of the heat generating layer 811 depending on the direction, and uneven distribution of heat generation in the heat generating layer 811 hardly occurs. On the other hand, the density of the wiring is lower than the examples shown in FIGS.

In the above-described example, the basic pattern is configured by connecting the side portions continuously and is a part of a regular polygon. However, the basic pattern is not limited thereto.
FIGS. 12A to 12B are diagrams illustrating an example in which still another basic pattern is used.
Here, FIG. 12B is a diagram for explaining a fourth example of the basic pattern constituting the pattern of the heat generating layer 811. FIG. 12A is a diagram illustrating a pattern of the heat generating layer 811 when the basic pattern of FIG. 12B is used.
As shown in the figure, the basic pattern in FIG. 12B is an arc, and the pattern of the heat generating layer 811 shown in FIG. 12A is formed by connecting arcs continuously.
Also in this example, there is almost no difference in the rigidity of the heat generating layer 811 depending on the direction, and it is possible to further reduce the unevenness of the heat generation distribution as compared with the examples shown in FIGS. On the other hand, the density of the wiring is lower than the examples shown in FIGS.

In the example described in detail above, when the basic pattern is composed of side portions, the angles formed by the side portions are almost the same angle, but are not limited thereto. As long as the angle formed by the side portions is an obtuse angle, the angles may be different from each other.
In the example described in detail above, there is one type of basic pattern, but it may be two or more types. For example, a basic pattern made up of a part of regular hexagons shown in FIG. 7C and a basic pattern made up of parts of regular pentagons shown in FIG. 11B may be mixed.
Further, in the example described in detail above, the wiring extends linearly in the axial direction. However, the wiring is not necessarily limited to this, and may extend in the axial direction with some undulation.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 60 ... Fixing unit, 61 ... Fixing belt, 62 ... Pressure roll, 80 ... Heater unit, 81 ... Heater, 82 ... Guide, 83 ... Mounting part, 811 ... Heat generating layer, 812 ... Insulating layer, 813 ... Thermal diffusion layer

According to the first aspect of the present invention, there is provided a fixing member that fixes a toner image on a recording material, and a fixing pressure unit that is pressed against the outer peripheral surface of the fixing member and through which the recording material that holds an unfixed toner image passes. The fixing member has a heating portion in which a wiring extending in the axial direction of the fixing member is formed by further connecting a pressure member to be formed and a shape in which the side portions are continuously connected so as to form an obtuse angle, and the fixing member And a heating member for heating the fixing device.
A second aspect of the present invention is the fixing device according to the first aspect, wherein the wiring is arranged in a plurality of rows in the rotation direction of the fixing member.
According to a third aspect of the present invention, the heating unit is configured such that, with respect to adjacent wirings, the top part of the shape that constitutes one of the wirings and the reverse of the rotational direction of the shape that constitutes the other wiring. The fixing device according to claim 2, wherein top portions protruding in the direction are alternately arranged in the axial direction.
According to a fourth aspect of the present invention, in the fixing device according to any one of the first to third aspects , the side portions constituting the shape have the same length.
The invention according to claim 5 is the fixing device according to any one of claims 1 to 4 , wherein the shape is a part of a regular hexagon.
According to the sixth aspect of the present invention, the wiring that extends in the axial direction of the fixing member that fixes the toner image on the recording material is formed by further connecting the shape in which the side portions are continuously connected so as to form an obtuse angle. The heating device includes a heating member that heats the fixing member and a fixing unit that fixes the heating member along the inner peripheral surface of the fixing member.
According to the seventh aspect of the present invention, the toner image forming portion for forming the toner image, the transfer portion for transferring the toner image to the recording material, the fixing member for fixing the toner image, and the outer peripheral surface of the fixing member are pressed against each other. By further connecting the pressure member and the shape that is continuously connected so that the side portion forms an obtuse angle, the pressure member has a heating portion in which wiring extending in the axial direction of the fixing member is formed, and the fixing member is heated. An image forming apparatus including a fixing unit including a heating member.

According to the first aspect of the present invention, it is possible to provide a fixing device in which deformation due to thermal expansion of the heating member is less likely to occur.
According to the second aspect of the present invention, the fixing member can be more easily heated.
According to the fourth aspect of the present invention, it is possible to provide a fixing device in which deformation due to thermal expansion of the heating member is less likely to occur.
According to invention of Claim 5 , the density of wiring can be improved.
According to the sixth aspect of the present invention, it is possible to provide a heating device that can heat the fixing member so as to reduce the unevenness of the temperature distribution.
According to the invention of claim 7 , it is possible to provide an image forming apparatus capable of forming an image with less gloss unevenness.

Claims (6)

A fixing member for fixing a toner image on a recording material;
A pressure member that is in pressure contact with the outer peripheral surface of the fixing member and forms a fixing pressure portion through which a recording material holding an unfixed toner image passes;
A heating part in which wiring extending in the axial direction is formed by connecting the side parts continuously so as to form an obtuse angle, or by further connecting a shape formed by an arc, and heating the fixing member A heating member;
A fixing device.   The fixing device according to claim 1, wherein the side portions constituting the shape are of equal length.   The fixing device according to claim 1, wherein the wiring is arranged in a plurality of rows in a rotation direction of the fixing member.   The fixing device according to claim 1, wherein the shape is a part of a regular hexagon. The side part is continuously connected so as to form an obtuse angle, or the shape constituted by the circular arc is further connected to have a heating part in which wiring extending in the axial direction is formed, and a toner image is formed on the recording material. A heating member for heating the fixing member to be fixed;
A fixing portion for fixing the heating member so as to be along the inner peripheral surface of the fixing member;
A heating device comprising: A toner image forming unit for forming a toner image;
A transfer portion for transferring a toner image to a recording material;
A fixing member that fixes the toner image, a pressure member that presses against the outer peripheral surface of the fixing member, and a side portion that is continuously connected so as to form an obtuse angle or a shape constituted by an arc is further connected. A fixing part comprising a heating part in which wiring extending in the axial direction is formed and heating the fixing member;
An image forming apparatus comprising:

Images