Fixing apparatus and image forming apparatus

Abstract

To provide a fixing device that can prevent the occurrence of trouble caused by a mistake in attaching a harness that connects a plurality of temperature detection means and a relay connector.SOLUTION: A fixing device 50 is installed in an image forming apparatus and comprises: a fixing member 60; a heating member 61; a pressure member 70 that is in pressure contact with the fixing member 60 to form a nip part; a plurality of temperature detection means 81; and an exterior member, and further comprises: a holding member 80 that is attached with the plurality of temperature detection means 81 and fixed to the external member; and harnesses 83 that are each connected at one end to a connector 82 of the temperature detection means 81, and connected at the other end to a relay connector 84 that transmits a detection signal of the temperature detection means 81 to the image forming apparatus. The holding member 80, the temperature detection means 81, and the harnesses 83 constitute a pre-assembled sub-assembly, the connectors 82 of the plurality of temperature detection means 81 in the sub-assembly are in substantially the same direction, and the harnesses 83 extend in a single direction without bending.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a fixing device and an image forming apparatus.

Background Art

[0002] In an image forming apparatus, a developer image is formed on an image carrier by an image forming process such as electrophotographic recording, electrostatic recording, magnetic recording, etc. This developer image is transferred to a recording medium (such as paper), and the developer image transferred to the recording medium is heated and pressed by a fixing device and fixed to the recording medium.

[0003] Since recording media of various sizes are used in image forming apparatuses, when the length of the heat source of the fixing device is adjusted to match the maximum size of the recording medium, the temperature of the end of the fixing member, which is a non-paper passing part, rises when fixing a small-sized recording medium. In contrast, a configuration is known in which a plurality of heat sources (for example, heating members such as halogen heaters) with different light distribution regions (heat distribution regions) in the width direction (longitudinal direction) of the endless fixing member are provided inside the endless fixing member.

[0004] In a mode of providing a plurality of heat sources, overlapping of the heat distribution regions occurs due to variations in the arrangement positions of the heat sources, and the temperature of the fixing member becomes locally high, which may cause image degradation and paper wrinkles due to uneven temperature of the fixing member. Therefore, a configuration has been proposed in which a plurality of temperature detection means for controlling each heat source are arranged at different positions in the axial direction.

[0005] Patent Document 1 discloses a fixing device in which air is blown against the non-detection surface of a temperature sensor so that the detection deviation of the temperature sensor is within a predetermined value, and a plurality of temperature sensors are arranged at different positions in the longitudinal direction corresponding to the heat distribution of the heat source.

Summary of the Invention

Problems to be Solved by the Invention

[0006] Incidentally, in a fixing device equipped with a temperature sensor, a relay connector for transmitting the temperature sensor signal to the main body of the image forming apparatus and a harness for connecting to the relay connector are provided. In the assembly process of the device, it is necessary to connect the harness to the temperature sensor connector, but in a configuration equipped with multiple temperature sensors, it is inefficient to connect the harness to each individual temperature sensor after arranging multiple temperature sensors at different positions along the longitudinal direction of the heat source.

[0007] Therefore, it is preferable to prepare a sub-assembly by performing a partial assembly (hereinafter referred to as "sub-assembly") in which multiple temperature sensors are attached to a holding member (bracket) in advance, and a harness for connecting to a relay connector is attached to the connector of each temperature sensor.

[0008] However, if the connectors of multiple temperature sensors attached to the bracket are oriented differently, stress such as bending can be placed on the harness when connecting to the intermediate connector, potentially causing disconnection or other problems. Furthermore, if harnesses of different lengths are not properly connected to each temperature sensor, the intermediate connector on the fixing device side may be positioned in a different location than desired, resulting in a malfunction where the wires cannot reach the intermediate connector on the image forming apparatus side. In such cases, reassembly will be required, incurring additional labor costs.

[0009] Therefore, the present invention provides a fixing device that can prevent malfunctions caused by the installation of a harness connecting multiple temperature sensing means and relay connectors. [Means for solving the problem]

[0010] To solve the above problems, the fixing device of the present invention is installed in an image forming apparatus and comprises a fixing member that heats a toner image to fix it to a recording medium, a heating member that heats the fixing member, a pressurizing member that presses against the fixing member to form a nip portion, a plurality of temperature sensing means, and an outer casing member that houses at least the fixing member and the pressurizing member, further comprising a holding member to which the plurality of temperature sensing means are attached and fixed to the outer casing member, and a harness to which one end is connected to a connector of the temperature sensing means and the other end is connected to a relay connector that transmits the detection signal of the temperature sensing means to the image forming apparatus, wherein the holding member, the temperature sensing means and the harness are pre-assembled into a sub-assembly, the orientation of the connectors of the plurality of temperature sensing means in the sub-assembly is substantially the same, and the harness is extended without bending in a single direction. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a fixing device that can prevent malfunctions caused by the installation of a harness connecting multiple temperature sensing means and relay connectors. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an image forming apparatus equipped with a fixing device according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of a fixing device according to one embodiment of the present invention. [Figure 3] This is a longitudinal side view of a fixing device according to one embodiment of the present invention. [Figure 4] This is an explanatory diagram showing an example of a sub-assembly with the harness correctly installed. [Figure 5] This is an explanatory diagram showing an example of a sub-assembly where the harness is not properly installed. [Modes for carrying out the invention]

[0013] The fixing apparatus and image forming apparatus according to the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and other embodiments, additions, modifications, and deletions can be made within the scope of what a person skilled in the art can conceive. Any embodiment that achieves the function and effect of the present invention is included within the scope of the present invention.

[0014] [Image forming apparatus] Figure 1 is a schematic cross-sectional view showing an example of an image forming apparatus as a color printer equipped with the fixing device of the present invention. The image forming apparatus 10 shown in Figure 1 comprises a fixing device 50 and an electrophotographic image forming unit, the image forming unit being equipped with a plurality of (four in the illustrated example) image forming means 1a, 1b, 1c, and 1d. These first to fourth image forming means 1a, 1b, 1c, and 1d each have the same configuration, except for the corresponding toner color. Therefore, these image forming means form, for example, a black toner image, a magenta toner image, a cyan toner image, and a yellow toner image. Since these image forming means have the same configuration except for the difference in developer (toner) color, the subscripts a, b, c, and d in the reference numerals will be omitted as appropriate in the following description.

[0015] The image forming means 1 contains a drum-shaped photoreceptor 2, which is an electrostatic latent image carrier. A charging member 3, a developing device 4, and a cleaning means 5 are provided around the photoreceptor 2. The photoreceptor 2 can be driven to rotate clockwise. The charging member 3 is pressed against the surface of the photoreceptor 2 and rotates in conjunction with the rotation of the photoreceptor 2. A predetermined bias voltage is applied to the charging member 3 by a high-voltage power supply (not shown), so that the surface of the rotating photoreceptor 2 can be uniformly charged. Although the charging member 3 shown here is a roller-shaped member that contacts the photoreceptor 2, it is also possible to use a non-contact type that utilizes corona discharge or the like.

[0016] In the image forming apparatus 10, an exposure device 6 is provided obliquely downward in parallel with four image forming means. The exposure device 6 has constituent members such as a light source, a polygon mirror, an f-θ lens, and a reflection mirror. The exposure device 6 exposes each photoreceptor 2 charged by a charging member 3 based on image information formed according to image data of each color toner, and creates an electrostatic latent image on the photoreceptor 2. The electrostatic latent image formed on the photoreceptor 2 using the exposure device 6 is developed and visualized by being applied with each color toner when passing through the developing device 4 due to the rotation of the photoreceptor 2.

[0017] Above the inside of the image forming apparatus 10, toner bottles 20a, 20b, 20c, and 20d filled with black, magenta, cyan, and yellow color toners are arranged. Toner of a predetermined replenishment amount is replenished to each color developing device 4a, 4b, 4c, and 4d from the toner bottles 20a, 20b, 20c, and 20d via a conveyance path not shown.

[0018] Also, an endless belt-shaped intermediate transfer belt 7, which is an intermediate transfer member, is arranged facing the photoreceptor 2 of the image forming means. The surface of the intermediate transfer belt 7 is in contact with the photoreceptor 2. The intermediate transfer belt 7 shown in FIG. 1 is configured by being wound around a plurality of support rollers (for example, support rollers 15a, 15b, etc.). And in the illustrated example, the support roller 15a is connected to a drive motor as a drive source not shown. By driving this drive motor, the intermediate transfer belt 7 rotates and moves counterclockwise in the figure, and the driven rotatable support roller 15b is rotated.

[0019] On the back surface of the intermediate transfer belt 7, a primary transfer roller 8 is arranged facing the photoreceptor 2 with the belt interposed therebetween. A primary transfer bias is applied to this primary transfer roller 8 from a high voltage power source not shown, and the toner image visualized by the developing device 4 is primarily transferred to the intermediate transfer belt 7.

[0020] The primary transfer residual toner left on the photoreceptor 2 without being transferred once is removed by the cleaning means 5 in order to prepare for the next image forming operation by the photoreceptor 2, and the toner on the photoreceptor 2 is completely removed.

[0021] In the image forming apparatus 10, a secondary transfer roller 18 as a secondary transfer device is provided on the downstream side in the driving direction of the intermediate transfer belt 7 of the primary transfer roller 8. The secondary transfer roller 18 faces the support roller 15b with the intermediate transfer belt 7 interposed therebetween. Then, a secondary transfer nip portion is formed by the secondary transfer roller 18 and the support roller 15b via the intermediate transfer belt 7.

[0022] The image forming apparatus 10 includes a paper feed cassette 30 as a recording medium loading unit, a feed roller 31, and a registration roller pair (alignment roller pair) 35. And, as viewed from the secondary transfer roller 18, a fixing device 50 and a paper discharge roller pair 36 are provided on the downstream side in the conveyance direction of the recording medium.

[0023] Next, the image forming operation will be described. In this image forming operation as well, the configuration in which a toner image is formed on each photoreceptor 2 and the toner image is transferred to the intermediate transfer belt 7 is substantially the same except that the color of the toner image is different. Therefore, the subscripts a, b, c, and d are omitted as necessary.

[0024] First, the photoreceptor 2 is rotationally driven in the clockwise direction by a driving source not shown. At this time, the surface of the photoreceptor is irradiated with light from a charging device not shown, and the surface potential is initialized. The surface of the photoreceptor 2 with the initialized surface potential is then uniformly charged to a predetermined polarity by the charging member 3. The charged photoreceptor surface is irradiated with laser light from the exposure device 6, whereby an electrostatic latent image is formed on the photoreceptor surface. At this time, the image information exposed to each photoreceptor 2 is monochromatic image information obtained by decomposing a desired full-color image into yellow, cyan, magenta, and black toner color information. The electrostatic latent image thus formed on the photoreceptor is visualized as a developed toner image when it passes through the developing device 4 and the toner of each color (developer) from the developing device 4 is applied.

[0025] Furthermore, the intermediate transfer belt 7 is driven to move counterclockwise in the figure. A primary transfer voltage with the opposite polarity to the toner charge polarity of the toner image formed on the photoreceptor is applied to the primary transfer roller 8 described above. This creates a transfer electric field between the photoreceptor 2 and the intermediate transfer belt 7. The toner image on the photoreceptor 2 is then electrostatically transferred to the intermediate transfer belt 7, which is driven to rotate in sync with the photoreceptor 2. In this way, the toner images of each color that are transferred are superimposed on the intermediate transfer belt 7 sequentially from the upstream side in the transport direction of the intermediate transfer belt 7, with synchronized timing, to form the desired full-color image.

[0026] The recording media (paper P) on which the image is formed are separated one sheet at a time from the stack of recording media loaded in the paper feed cassette 30 to the register roller pair 35 by the action of appropriately positioned transport members such as feed rollers 31. During feeding, the leading edge of the transported recording media comes into contact with the nip portion of the register roller pair 35, which has not yet started rotating, forming a so-called loop, thereby performing registration of the recording media.

[0027] Subsequently, the rotational drive of the registration roller pair 35 is started in coordination with the full-color toner image supported on the intermediate transfer belt 7. The recording medium is then fed towards the secondary transfer nip section, which consists of the support roller 15b and the opposing secondary transfer roller 18 via the intermediate transfer belt 7. In this embodiment, a transfer voltage with the opposite polarity to the toner charge polarity of the toner image on the surface of the intermediate transfer belt is applied to the secondary transfer roller 18. As a result, the full-color toner image formed on the surface of the intermediate transfer belt 7 is transferred to the recording medium in one go.

[0028] The recording medium onto which the toner image has been transferred is transported to the fuser 50, where heat and pressure are applied to fix the toner image. The recording medium is then discharged to an output tray or similar outlet via the paper output roller pair 36, completing the image forming operation. Furthermore, any residual toner that remains on the intermediate transfer belt 7 without being transferred at the secondary transfer nip section where the secondary transfer roller 18 is located is removed and recovered by the intermediate transfer belt cleaning means 19.

[0029] [Fusing device] Next, an example of the configuration of the fixing device 50 will be described below with reference to Figure 2. The fixing device 50 shown in Figure 2 comprises a fixing belt 60 as a rotatable fixing member and a pressure roller 70 as a pressure member that is rotatably mounted in contact with the outer circumferential surface of the fixing belt 60.

[0030] The fixing belt 60 includes a heating member 61 (also called a heat source or heater) that heats the fixing belt 60, a pad 96 which is a nip forming member that is positioned opposite the pressure roller 70, and a support member 90 which is a nip support member that supports the pad 96. The fixing device 50 further includes a side plate 52 for fixing the holder 51 and the support member 90, and biasing means (not shown) for biasing the pressure roller 70 against the fixing belt 60 to form a nip surface N.

[0031] The fixing belt 60 is composed of a thin, flexible, endless belt member (including a film). The fixing belt 60 also includes an inner circumferential base material made of a metal material such as nickel or SUS, or a resin material such as polyimide (PI). The outer circumferential side of the base material is composed of a release layer made of tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE), etc. An elastic layer made of a rubber material such as silicone rubber, foamed silicone rubber, or fluororubber may be interposed between the base material and the release layer.

[0032] The pressure roller 70 is composed of a core metal 72, an elastic layer 71 made of foamed silicone rubber, silicone rubber, or fluororubber, etc., provided on the surface of the core metal 72, and a release layer (not shown) made of PFA or PTFE, etc., provided on the surface of the elastic layer 71. The pressure roller 70 is biased toward the fixing belt 60 by a biasing means (not shown) and is in contact with the pad (nip forming member) 96 via the fixing belt 60.

[0033] Where the pressure roller 70 and the fixing belt 60 are in contact, the elastic layer 71 of the pressure roller 70 is compressed, forming a nip portion (nip) N with a predetermined width n. The pressure roller 70 is configured to be rotationally driven by a drive source such as a motor (not shown) provided in the main body of the image forming apparatus. When the pressure roller 70 is rotationally driven, the driving force is transmitted to the fixing belt 60 at the nip N, causing the fixing belt 60 to rotate in response.

[0034] In this embodiment, the pressure roller 70 is a solid roller, but it may also be a hollow roller. In that case, a heat source such as a halogen heater may be placed inside the pressure roller 70.

[0035] If the pressure roller 70 is not provided with an elastic layer 71, the heat capacity will decrease and fixing performance will improve. However, when the unfixed toner is compressed and fixed, minute irregularities on the surface of the fixing belt 60 may be transferred to the image, potentially causing uneven gloss in the solid areas of the image. To prevent this, it is preferable to provide an elastic layer 71. The elastic layer 71 can be made, for example, 100 μm or thicker, which allows it to absorb minute irregularities through elastic deformation and avoid the occurrence of uneven gloss. Examples of materials for the elastic layer 71 include solid rubber and sponge rubber. If there is no heat source inside the pressure roller 70, sponge rubber is preferred from the viewpoint of heat insulation. Furthermore, the fixing belt 60 and the pressure roller 70 are not limited to being pressed against each other; they can also be simply in contact.

[0036] The pad 96, which is a nip-forming member, is arranged longitudinally along the rotation axis of the fixing belt 60 or the rotation axis of the pressure roller 70, and is supported by the support member 90. Both ends of the support member 90 are fitted into mounting holes 53 (only one side is shown in Figure 2) formed in the side plate 52 fixed to the housing of the fixing device, so that the support member 90 and the pad 96 do not displace even when subjected to pressure from the pressure roller 70.

[0037] Holders 51, which are retaining members for the fixing belt 60, are formed on the left and right side plates 52. The holder 51 on the left side plate 52 and the holder 51 on the right side plate 52 are formed to protrude opposite each other. Each holder 51 has a notched annular curved protrusion, and each outer curved surface slides against the inner walls on both sides of the annular fixing belt 60, suppressing rotational displacement of the fixing belt 60 in the radial and axial directions.

[0038] The support member 90 is preferably made of a metal material with high mechanical strength, such as stainless steel or iron, in order to satisfy the function of preventing deflection of the pad 96. In this case, it is preferable that each plate material of the support member 90 is made by punching out steel plates. By making it from steel plates, an inexpensive and highly rigid support member 90 can be made.

[0039] Examples of heating elements 61 include halogen heaters and the like. In this embodiment, two heating elements 61, a central heater 61a and an end heater 61b, are used in parallel. In the following description, the term "heating element 61" will be used to refer collectively to the central heater 61a and the end heater 61b. The number of heating elements 61 is not limited to two.

[0040] The two heating elements 61 have different heating ranges, allowing the fixing belt 60 to be heated according to the size of the paper P fed through the fixing device 50. The fixing device 50 of this embodiment includes two heaters: a central heater 61a that heats a position corresponding to the longitudinal central region of the fixing belt 60, and an end heater 61b that heats a position corresponding to the longitudinal end region of the fixing belt 60. When feeding wide paper such as A3 portrait, both the central heater 61a and the end heater 61b are lit. On the other hand, when feeding narrow paper such as A4 portrait, only the central heater 61a is lit. Therefore, the power consumption used to heat the fixing belt 60 can be reduced.

[0041] A shielding member (not shown) is provided between the fixing belt 60 and the heating member 61, and functions as a shielding member that partially (for example, at the axial end) blocks heat from the heating member 61. This makes it possible to suppress excessive temperature rise in the non-paper-feeding area of ​​the fixing belt 60, especially during continuous paper feeding, and prevents deterioration and damage to the fixing belt 60 due to heat.

[0042] Next, the basic operation of the fixing device 50 according to this embodiment will be described. When the power switch (not shown) on the printer is turned on, power is supplied to the heating element 61, and the pressure roller 70 begins to rotate clockwise in Figure 2. As a result, the fixing belt 60 rotates counterclockwise in Figure 2 due to the frictional force with the pressure roller 70.

[0043] Subsequently, the paper P (see Figure 2), which is an image carrier on which the unfixed toner image T is carried by the image forming process described above, is transported in the direction of arrow A1 in Figure 2, guided by a guide plate (not shown). Here, the pressure mechanism causes the pressure roller 70 to press against the fixing belt 60, and the paper P is fed into the nip N formed in the clamping section between the pressure roller 70 and the fixing belt 60. Then, the heat from the fixing belt 60 heated by the heating member 61 and the pressure between the fixing belt 60 and the pressure roller 70 fix the toner image T to the surface of the paper P.

[0044] The paper P on which the toner image T has been fixed is discharged from the nip N in the direction of arrow A1 in Figure 2. At this time, the leading edge of the paper P comes into contact with the leading edge of the separating member 75, which is supported by the side plate 52, and the paper P is separated from the fixing belt 60. Subsequently, the separated paper P is discharged outside the machine by the paper output roller as described above and stored in the paper output tray.

[0045] The support member 90 is engaged and fixed in mounting holes 53 provided in the left and right side plates 52. The support member 90, fixed at both ends to the left and right side plates 52, integrally supports the pad 96 in its main longitudinal region and is configured to receive the pressure Pr from the pressure roller 70 applied to the pad 96 as a double-supported beam. That is, the support member 90 receives the pressure Pr at multiple load input sections g1 at the ends opposite the pad 96 and transmits the pressure Pr from the load output sections g2 to the edges of the left and right mounting holes 53 of the left and right side plates 52.

[0046] The support member 90 has a configuration in which a flat plate-shaped upper stay 91 with one end straight, a bent plate-shaped lower stay 92, and a vertically oriented flat plate-shaped stay (vertical stay) 93 are combined in a triangular shape when viewed from the side. The upper stay 91 and the lower stay 92 are integrally joined at their overlapping end (the left end in Figure 2), and are fitted into the fitting portion 95 of the vertical stay 93 and crimped. Multiple fitting portions 95 are arranged in two rows in the direction between stays (up and down in Figure 2), forming a row-like structure. Since the length L1 between the end faces in the short direction (left-right direction in Figure 2) of the two plate materials forming the support member 90 is aligned, a simple shape can be adopted, thereby improving the assembly accuracy of the nip support member. Moreover, assembly accuracy and joint rigidity can be ensured, and shape rigidity can be ensured as a double-supported beam.

[0047] Figure 3 is a longitudinal side view of a fixing device according to one embodiment of the present invention. The fixing device of this embodiment is installed in an image forming apparatus and comprises a fixing belt 60 which is a fixing member that heats the toner image and fixes it to a recording medium, a heating member 61 which heats the fixing belt 60, a pressure roller 70 which is a pressure member that presses against the fixing member to form a nip portion, a plurality of temperature sensing means 81, and an outer casing member that houses at least the fixing member and the pressure member. The fixing device of this embodiment further comprises a retaining member (hereinafter also referred to as a "bracket") 80 to which a plurality of temperature sensing means 81 are attached and which is fixed to an exterior member, and a harness 83 to which one end is connected to a connector of the temperature sensing means 81 and the other end is connected to a relay connector 84 that transmits the detection signal of the temperature sensing means to the image forming apparatus.

[0048] The pressure roller 70 has a gear 55 installed at one end in the longitudinal direction (the right end in Figure 3) that meshes with a drive gear of a drive mechanism (not shown), and the pressure roller 70 is controlled to rotate by the main control unit. In addition, both ends of the pressure roller 70 in the width direction are rotatably supported by the side plates 52 of the fixing device 50 via bearings 54.

[0049] In the fixing device of this embodiment, the retaining member (bracket) 80, the temperature sensing means 81, and the harness 83 are pre-assembled subassemblies, the orientation of the connectors of the multiple temperature sensing means 81 in the subassembly is substantially the same, and the harness 83 extends without bending in a single direction.

[0050] Examples of subassemblies are shown in Figures 4 and 5. Figure 4 shows an example where the harness 83 is properly installed, while Figure 5 shows a comparative example where the harness 83 is installed incorrectly. In this embodiment, two temperature sensing means 81 (81a, 81b) are attached to the bracket 80, and the orientation of the connectors 82 (82a, 82b) is the same. Therefore, when the harness 83 is connected correctly, the harness 83 connected to the connector 82b of the left temperature sensing means 81b is short, and the harness 83 connected to the connector 82a of the right temperature sensing means 81a is long.

[0051] As shown in Figure 4, when the harness 83 is connected correctly, the relay connector 84 is located on the left side of the bracket 80. However, as shown in Figure 5, when the harness 83 is connected incorrectly, the relay connector 84 ends up located near the center of the bracket 80. Thus, according to this embodiment, if there is an error in the installation of the harness 83, the error can be easily visually identified at the time of sub-assembly.

[0052] Furthermore, as shown in Figure 4, when the harness 83 is connected correctly, the harness 83 extends without bending in one direction, but as shown in Figure 5, when the harness 83 is connected incorrectly, bending occurs in the harness 83. According to this embodiment, since the orientation of the connector 82 is the same, there is no need to fold the harness back, thus preventing malfunctions such as wire breakage or insulation damage due to bending load.

[0053] Examples of temperature detection means (temperature sensor) 81 include an infrared detection element that receives infrared light to detect the temperature of the heating element 61. In this embodiment, a thermopile element is used.

[0054] In the sub-assembly of this embodiment, the harness 83 is routed along the back side of the surface of the holding member (bracket) 80 that faces the heating member 61. By routing the harness 83 along the back of the bracket 80, it is possible to prevent it from being directly exposed to heat from the heating element 61 and reduce thermal degradation of the harness 83.

[0055] In the sub-assembly of this embodiment, it is preferable that the connector 82 of the temperature sensing means 81 is disposed on the back side of the surface of the holding member (bracket) 80 that faces the heating member 61, and is not exposed from the holding member 80 in a plan view as seen from the heating member 61 side. By providing the connector 82 on the back surface of the bracket 80, it is possible to prevent it from being directly exposed to heat from the heating element 61 and reduce thermal degradation of the connector 82.

[0056] In configurations where the harness 83 and connector 82 may be exposed from the bracket 80 in the region receiving heat from the heating element 61, measures such as enlarging the bracket 80 or covering the exposed components to improve their heat resistance become necessary to prevent thermal degradation, which leads to increased costs. On the other hand, in this embodiment, the harness 83 and connector 82 can be arranged to be covered by the bracket 80, thus addressing these problems.

[0057] In the sub-assembly of this embodiment, the connector 82 of the temperature sensing means 81 faces the end of the fixing device in the longitudinal direction that is closer to the position where the retaining member (bracket) 80 is installed. In Figure 3, the left end corresponds to the end closer to the position where the bracket 80 is installed. By aligning the orientation of the connector 82 towards the left end in Figure 3, the harness 83 can be shortened.

[0058] In this embodiment shown in Figure 3, the relay connector 85 on the image forming apparatus side is provided on the left end side. By positioning the bracket 80 close to the end where the relay connector 85 is provided, the distance to the relay connector 85 can be shortened, and the distance over which the harness 83 is exposed from the bracket 80 can also be shortened. This reduces the deterioration of the harness 83 due to the effects of heat.

[0059] In the subassembly of this embodiment, the connector 82 of the temperature sensing means 81 faces the end of the longitudinal end of the fixing device that does not have a drive mechanism for driving the pressurizing member 70 and / or fixing member 60. In this embodiment shown in Figure 3, since the gear 55 constituting the drive mechanism is located at the right end, it is preferable to align the orientation of the connector 82 toward the left end in Figure 3. If the harness 83 is routed near the location of the drive mechanism, parts such as clamps and guard members will be required to prevent entanglement, leading to increased complexity and cost for the mechanism. In contrast, in this embodiment, the harness 83 is routed along the end side where the drive mechanism is not installed, thus preventing an increase in the number of parts, complexity of the mechanism, and increased costs.

[0060] As described above, the fixing device of this embodiment is sub-assembled with a holding member 80, a temperature sensing means 81, and a harness 83. Since the orientation of the connectors 82 of the multiple temperature sensing means 81 in the sub-assembly is substantially the same, when the harness 83 is attached to the fixing device and the relay connector 84 at one end of the harness 83 is connected to the relay connector 85 on the image forming apparatus side, the harness 83 extends without bending in a single direction. If the harness 83 does not extend in a single direction and is bent, this can be easily visually recognized at the time of sub-assembly, thus preventing increased man-hours required for reassembly and preventing problems such as damage to the harness.

[0061] Examples of the present invention are as follows: <1> A fixing device installed in an image forming apparatus, comprising: a fixing member for heating and fixing a toner image onto a recording medium; a heating member for heating the fixing member; a pressurizing member for pressing against the fixing member to form a nip portion; a plurality of temperature sensing means; and an outer casing member for housing at least the fixing member and the pressurizing member, The plurality of temperature sensing means are attached to a holding member that is fixed to the exterior member, The system further comprises a harness, one end of which is connected to the connector of the temperature sensing means, and the other end of which is connected to a relay connector that transmits the detection signal of the temperature sensing means to the image forming apparatus, The fixing device is characterized in that the holding member, the temperature sensing means, and the harness are pre-assembled into a sub-assembly, the orientation of the connectors of the multiple temperature sensing means in the sub-assembly is substantially the same, and the harness extends without bending in a single direction. <2> The harness is characterized in that it is routed along the back side of the surface of the holding member facing the heating member. <1> This is the fixing device described in [reference]. <3> The connector of the temperature sensing means is disposed on the back side of the surface of the holding member facing the heating member, and is not exposed from the holding member in a plan view as seen from the heating member side. <1> or <2> This is the fixing device described in [reference]. <4> The connector of the temperature sensing means is characterized in that it faces the end of the longitudinal end of the fixing device that is closer to the position where the holding member is disposed. <1> from <3> It is a fixing device as described in any of the following. <5> The connector of the temperature sensing means is characterized in that it faces the end of the longitudinal end of the fixing device that does not have the pressurizing member and / or the drive mechanism for driving the fixing member. <1> from <4> It is a fixing device as described in any of the following. <6> The aforementioned <1> from <5> This is an image forming apparatus characterized by being equipped with a fixing device as described in any of the above. [Explanation of symbols]

[0062] 10 Image forming apparatus 50 Fixing device 51 Holder 52 Side panel 60 Fixing belt 61 Heating element 70 Pressure rollers 80 Bracket (holding member) 81 Temperature sensor (temperature detection means) 82 connectors 83 Harness 84. Relay connector (fuser side) 85. Relay connector (image forming apparatus side) 90 Support Member 96 pads [Prior art documents] [Patent Documents]

[0063] [Patent Document 1] Japanese Patent Publication No. 2021-43303

Claims

1. A fixing device installed in an image forming apparatus, comprising: a fixing member for heating and fixing a toner image onto a recording medium; a heating member for heating the fixing member; a pressurizing member for pressing against the fixing member to form a nip portion; a plurality of temperature sensing means; and an outer casing member for housing at least the fixing member and the pressurizing member, The plurality of temperature sensing means are attached to a holding member that is fixed to the exterior member, The system further comprises a harness, one end of which is connected to the connector of the temperature sensing means, and the other end of which is connected to a relay connector that transmits the detection signal of the temperature sensing means to the image forming apparatus, A fixing device characterized in that the holding member, the temperature sensing means, and the harness are pre-assembled into a sub-assembly, the orientation of the connectors of the multiple temperature sensing means in the sub-assembly is substantially the same, and the harness is extended without bending in a single direction.

2. The fixing device according to claim 1, characterized in that the harness is routed on the back side of the surface of the holding member that faces the heating member.

3. The fixing device according to claim 1 or 2, characterized in that the connector of the temperature sensing means is disposed on the back side of the surface of the holding member facing the heating member, and is not exposed from the holding member in a plan view as seen from the heating member side.

4. The fixing device according to claim 1 or 2, characterized in that the connector of the temperature sensing means faces the end of the fixing device in the longitudinal direction that is closer to the position where the holding member is disposed.

5. The fixing device according to claim 1 or 2, characterized in that the connector of the temperature sensing means faces the end of the fixing device in the longitudinal direction that does not have the pressurizing member and / or the drive mechanism for driving the fixing member.

6. An image forming apparatus characterized by comprising the fixing device described in claim 1 or 2.

Images