Fixing device

Abstract

We provide a new type of fixing device that builds upon conventional technology. [Solution] The fixing device includes a fixing belt, a plate-shaped substrate, a heating resistor provided on the substrate, and an electrode electrically connected to the heating resistor and provided at the end of the substrate in the longitudinal direction of the substrate, the heater being disposed in the internal space of the fixing belt, a holder that holds the heater in the longitudinal direction, a conductive contact that contacts the electrode, and a housing that accommodates the contact. The holder has an integrally molded retaining portion to prevent the power supply connector from coming off the heater, and the contact has a first portion that contacts the electrode and a second portion that, together with the first portion, sandwiches the heater and the holder, and has a U-shape when viewed in the longitudinal direction.

Description

Technical Field

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

Background Art

[0002] The fixing device described in Patent Document 1 includes a heating unit having a heater for heating the inner surface of a belt, and a pressure roller that forms a nip portion together with the heater via a fixing film, and fixes the toner on the recording material. The heating unit is provided with a power supply connector, and the power supply connector is provided with a contact member that contacts an electrode portion of the heater to generate heat when energized.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a new form of fixing device that develops on the basis of the prior art.

Means for Solving the Problems

[0005] One aspect of the present invention is a fixing apparatus for fixing a toner image formed on a recording material by the heat of the heater via the fixing belt, wherein the heater comprises a cylindrical fixing belt, a plate-shaped substrate, a heating resistor provided on the substrate, and an electrode electrically connected to the heating resistor and provided at the end of the substrate in the longitudinal direction of the substrate, the heater being disposed in the internal space of the fixing belt, a holder being disposed in the internal space of the fixing belt and holding the heater over the longitudinal direction, and a power supply connector for supplying power to the heater, the power supply connector comprising a conductive contact that contacts the electrode and a housing that accommodates the contact, the fixing apparatus for fixing a toner image formed on a recording material by the heat of the heater via the fixing belt, wherein the holder has an integrally molded retaining portion to prevent the power supply connector from coming off the heater, the contact has a first portion that contacts the electrode and a second portion that, together with the first portion, sandwiches the heater and the holder, and the shape when viewed in the longitudinal direction is U-shaped. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a new form of fixing device that is an advancement of the conventional technology. [Brief explanation of the drawing]

[0007] [Figure 1] Cross-sectional view of the image forming apparatus according to Example 1. [Figure 2] Cross-sectional view of the fuser according to Example 1. [Figure 3] Cross-sectional view of the fuser according to Example 1. [Figure 4] An exploded perspective view of the fuser according to Example 1. [Figure 5] Bottom view of the holder according to Example 1. [Figure 6] An exploded perspective view of the holder, temperature sensor, biasing member, and stay according to Example 1. [Figure 7] A bottom view showing the heater, holder, and belt according to Example 1. [Figure 8]Bottom view of the heater according to Example 1. [Figure 9] (a) is a perspective view showing the connector according to Example 1 just before it is attached to the holder, and (b) is a perspective view showing the connector attached to the holder. [Figure 10] A cross-sectional view showing a cross-section perpendicular to the Y direction of the holder and contact according to Example 1. [Figure 11] (a) is a cross-sectional view showing a cross-section of the holder and contact according to Example 2 perpendicular to the Z direction, and (b) is a cross-sectional view showing a cross-section of the holder and contact perpendicular to the Y direction. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. The dimensions, materials, shapes, and relative arrangements of the components described in each of the following embodiments may be appropriately modified depending on the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless otherwise specifically stated, the scope of the present invention is not limited to these embodiments.

[0009] Figure 1 is a cross-sectional view of an electrophotographic image forming apparatus 1 to which the fuser 6 of this embodiment is applied. In the following description, as shown in Figure 1, the nip direction in the nip section np1 of the fuser 6, which will be described later, will be referred to as the Z direction. The direction intersecting the Z direction will be referred to as the Y direction. The Y direction is parallel to the rotation axis direction of the pressurizing rotating body 62, which will be described later. The direction intersecting both the Z and Y directions will be referred to as the X direction. The X direction is parallel to the direction in which the heating unit 61, which will be described later, transports the recording material located in the nip section. The X and Y directions are preferably horizontal. Furthermore, the X, Y, and Z directions are preferably orthogonal to each other. In addition, as necessary, the directions of the arrows X, Y, and Z shown in each drawing will be referred to as the +X side, +Y side, and +Z side, respectively, and the opposite sides will be referred to as the -X side, -Y side, and -Z side, respectively. In the following description, the direction in which the recording material is transported in the nip section np1, which will be described later, will be referred to as the recording material transport direction (+X direction). Furthermore, the direction of the rotation axis of the pressurized rotating body 62, which will be described later, is called the axial direction. In the axial direction, the direction from one transmission member 617b towards the other transmission member 617b, which will be described later, is called the first axial direction (+Y direction). In the axial direction, the direction opposite to the first axial direction is called the second axial direction (-Y direction). The Y direction is also the longitudinal direction of the heating unit 61. Also, the Y direction is the generatrix direction of the belt 614.

[0010] <Example 1> [Configuration of the image forming apparatus] The configuration of the image forming apparatus 1 according to Embodiment 1 will be explained using Figure 1. The image forming apparatus 1 comprises an apparatus body 2, a process cartridge 10, and a fuser 6. The process cartridge 10 is detachably attached to the apparatus body 2. The fuser 6 is detachably attached to the apparatus body 2. It can also be said that the fuser 6 is mounted on the apparatus body 2. Note that the fuser 6 may be attached in a non-detachable manner.

[0011] The main unit 2 of the apparatus comprises a paper feed tray 3, a sheet feeding unit 4, a transport path P, a transfer roller 51, a sheet discharge unit 7, a paper output tray 8, a laser scanner 9, and an opening / closing door 21. The process cartridge 10 comprises a photosensitive drum 11 and a developing roller 12 as a developer carrier. The process cartridge 10 also contains developer inside. The opening / closing door 21 is supported so as to be rotatable around a pivot axis 21a and is configured to move between a closed position that closes the opening 2a and an open position that opens the opening 2a. When the opening / closing door 21 is in the open position with the opening 2a open, the process cartridge 10 can be attached to and detached from the main unit 2 through the opening 2a.

[0012] The sheet feeding unit 4 consists of a paper feed roller 41, a separation roller 42, a separation pad 42a, and a transport roller pair 43. Based on the print start signal, the sheet S stored in the paper feed tray 3 is sent to the transport path P by the sheet feeding unit 4 and transported towards the transfer roller 51 via the registration roller pair 44.

[0013] When the sheet S is transported to a predetermined position, an image formation start signal is issued, and the image formation process begins. The photosensitive drum 11, which is rotated by a drive source (motor) (not shown), is uniformly charged to a predetermined potential by a charging means (not shown). The surface of the charged photosensitive drum 11 is exposed by a laser scanner 9 based on image information, and an electrostatic image is formed in which the charge of the exposed area is removed. The toner in the process cartridge 10 is carried on the developing roller 12 and supplied to the photosensitive drum 11 according to the electrostatic latent image, developing the latent image. As a result, the latent image is made visible on the photosensitive drum 11 as a toner image.

[0014] The transfer roller 51 is disposed opposite to the photosensitive drum 11 of the process cartridge 10. When the sheet S conveyed by the resist roller pair 44 passes through the nip between the photosensitive drum 11 and the transfer roller 51, a voltage is applied from the apparatus main body 2 to the transfer roller 51, and the toner image on the photosensitive drum 11 is transferred to the sheet S as an unfixed image. Thereafter, the sheet S onto which the toner image has been transferred is conveyed to the fixing device 6 provided with a heating unit 61 and a pressure rotating body 62. The fixing device 6 is a fixing device that fixes a toner image (developer image) to a recording material. When the sheet S passes through the nip between the heating unit 61 and the pressure rotating body 62, the unfixed image transferred onto the sheet S is heated and pressurized to be fixed on the surface of the sheet S. The sheet S onto which the toner image has been fixed is discharged to the paper discharge tray 8 through the sheet discharge unit 7.

[0015] [Configuration of Fixing Device] Next, the configuration of the fixing device 6 will be described. FIG. 2 is a cross-sectional view of the fixing device 6. As shown in FIG. 2, the heating unit 61 includes a heater 611, a holder 612, a stay 613, and a belt 614 (also referred to as a fixing film) as a fixing belt. The heater 611 is provided in the internal space of the belt 614 and heats the belt 614. The heater 611 extends in the generatrix direction (Y direction) of the belt 614, and the shape of the heater 611 is flat. The heater 611 has a first surface 611a and a second surface 611b on the opposite side of the first surface 611a, and the first surface 611a is held by the holder 612.

[0016] The holder 612 is formed of a heat-resistant resin such as PPS or liquid crystal polymer, and has a guide surface 612a and a support wall 612b. The guide surface 612a contacts the inner peripheral surface 614a of the belt 614 to guide the belt 614, and the support wall 612b has a support surface 612b1 that supports the heater 611. The support surface 612b1 of the support wall 612b is in contact with the first surface 611a of the heater 611. The stay 613 is a member that supports the holder 612, and is formed by bending a steel plate having a greater rigidity than the holder 612, for example, a steel plate with a thickness of 1.6 mm, into a substantially U shape.

[0017] The belt 614 is an endless belt formed in a cylindrical shape and having heat resistance and flexibility, and is composed of, for example, a metal sleeve such as stainless steel coated with a fluororesin, or a laminate of a polyimide resin, a silicone rubber, a fluororesin, etc. A heater 611, a holder 612, and a stay 613 are arranged in the internal space of the belt 614, and the belt 614 is configured to rotate around these. The inner peripheral surface 614a of the belt 614 contacts the second surface 611b of the heater 611.

[0018] The pressing rotator 62 (pressing roller) has a metal shaft 62a and a roller 62b made of an elastic body covering the shaft 62a, and is pressed against the heater 611 via the belt 614. The pressing rotator 62 forms a nip portion np1 for nipping, heating, and pressing the sheet S by sandwiching the belt 614 between itself and the heater 611. That is, it can be said that the pressing rotator 62 (pressing roller) forms the nip portion np1 together with the heater 611 via the belt 614. That is, the pressing rotator 62 heats and presses the sheet S together with the heater 611 at the nip portion np1.

[0019] The pressing rotator 62 is configured to rotate when a driving force from a driving source provided in the image forming apparatus 1 is transmitted thereto. When the pressing rotator 62 rotates, the belt 614 rotates passively. The sheet S with the toner image transferred is conveyed between the pressing rotator 62 and the heated belt 614, and the toner image is thermally fixed.

[0020] Next, the frame configuration of the fuser 6 will be described using Figure 3. Figure 3 is a cross-sectional view of the fuser 6. The fuser 6 has an upper frame 64 and a lower frame 63. The lower frame 63 can also be called the first frame and the upper frame 64 can be called the second frame. The lower frame 63 is the frame that supports the heating unit 61 and the pressurizing rotating body 62. The upper frame 64 is located above the lower frame 63 and covers the heating unit 61. The lower frame 63 and the upper frame 64 are resin members formed by non-conductive molded members (resin members). The upper frame 64 has an upper guide surface 64a located downstream of the heating unit 61 in the recording material transport direction (+X). The upper guide surface 64a guides the upper surface of the sheet S being transported in the recording material transport direction. The lower frame 63 has a lower guide surface 63a located downstream of the heating unit 61 in the recording material transport direction. The lower guide surface 63a guides the lower surface of the sheet S being transported in the recording material transport direction.

[0021] Next, the configuration of the lower frame 63 that supports the pressurized rotating body 62 will be described using Figure 4. Figure 4 is an exploded perspective view of the fuser 6. The lower frame 63 has rails 63b at its ends in the first axial direction and the second axial direction, respectively. The rails 63b extend vertically and support the holder 612 so that it can move vertically. The two rails 63b face each other in the axial direction. The rails 63b engage with grooves 617a1 and 617b1 provided in the transmission members 617a and 617b, respectively.

[0022] The fixing unit 6 includes bearings 62c and 62d. The ends of the shaft 62a in the first axial direction and the ends in the second axial direction are supported by bearings 62c and 62d, respectively. Bearing 62c has a protrusion 62c1, which fits into a recess 63d1 provided in the lower frame 63, thereby positioning it relative to the lower frame 63. Similarly, bearing 62d has a protrusion 62d1, which fits into a recess 63d2 provided in the lower frame 63, thereby positioning it relative to the lower frame 63. Bearing 62c is electrically conductive. In this configuration, bearings 62c and 62d are provided with protrusions 62c1 and 62d1, and the lower frame 63 is provided with recesses 63d1 and 63d2, but the relationship between the protrusions and recesses may be reversed. Also, the means for fixing bearings 62c and 62d to the lower frame 63 does not have to be of a protrusion-recess shape.

[0023] Figure 5 is a bottom view showing the holder 612. Figure 5 is a view of the holder 612 in the -Z direction. Figure 6 is an exploded perspective view showing the holder 612, temperature sensors 613a and 613b, biasing members 613c and 613d, and stay 613. As shown in Figure 5, the support wall 612b of the holder 612 has a plurality of holes 612b2 and 612b3.

[0024] As shown in Figure 6, temperature sensors 613a and 613b are provided on the back surface 612b4 of the holder 612, opposite to the support surface 612b1. The temperature sensors 613a and 613b contact the first surface 611a of the heater 611 through holes 612b2 and 612b3. The temperature sensors 613a and 613b are pressed against the first surface 611a of the heater 611 (see Figure 2) by biasing members 613c and 613d provided between the stay 613 and the temperature sensors 613a and 613b. The temperature sensor 613a is located at one end of the holder 612 in the longitudinal direction.

[0025] The temperature sensor 613b is located closer to one end of the holder 612 than to the center in the longitudinal direction (Y direction). In this embodiment, the temperature sensors 613a and 613b are thermistors, but other temperature sensors such as thermostats can also be used. In this embodiment, the biasing members 613c and 613d are coil springs, but other biasing members may also be used.

[0026] Figure 7 is a bottom view showing the heater 611, holder 612, and belt 614. As shown in Figures 4 and 7, the holder 612 extends longitudinally (Y direction) through the inside of the belt 614, with both longitudinal ends extending outward from the belt 614. The holder 612 supports the heater 611, and a connector 616 is provided at one longitudinal end of the heater 611 as a power supply connector that supplies power to the heater 611 and clamps the heater 611 and the holder 612.

[0027] In this embodiment, the pressurizing rotating body 62 is configured to include a shaft 62a and a roller 62b, but it is not limited to this configuration. For example, instead of the pressurizing rotating body 62, a pressurizing belt that is pressed against the belt 614 of the heating unit 61 can be used.

[0028] [heater] Figure 8 is a bottom view of the heater 611. As shown in Figure 8, the heater 611 has a plate-shaped substrate 900 extending in the longitudinal direction (Y direction), and heating resistors 901a and 901b mounted on the substrate 900 and provided along the longitudinal direction. Conductors 902a to 902c are connected to both ends of the two heating resistors 901a and 901b in the longitudinal direction.

[0029] One end of conductor 902a is connected to electrode 903a for heating resistors, and the other end of conductor 902a is connected to heating resistor 901a. One end of conductor 902b is connected to heating resistor 901a, and the other end of conductor 902b is connected to heating resistor 901b. One end of conductor 902c is connected to heating resistor 901b, and the other end of conductor 902c is connected to electrode 903b for heating resistors. In other words, electrodes 903a and 903b are electrically connected to heating resistors 901a and 901b. Therefore, by passing current between electrodes 903a and 903b, the heating resistors 901a and 901b are heated simultaneously in this heater circuit configuration.

[0030] Here, the center line of electrode 903a in the short direction (X direction) is defined as center line 903c, the center line of electrode 903b in the short direction (X direction) is defined as center line 903d, and the center line of heater 611 in the short direction (X direction) is defined as center line c1. In this case, the center lines 903c and 903d of electrodes 903a and 903b are located upstream of the center line c1 of heater 611 in the mounting direction (+X direction) of connector 616. Note that it is not necessary for both center lines 903c and 903d of electrodes 903a and 903b to be located upstream of the center line c1 of heater 611 in the mounting direction (+X direction) of connector 616. Center line 903c is an example of a first center line, and center line c1 is an example of a second center line.

[0031] [connector] Figure 9(a) is a perspective view showing the connector 616 just before it is attached to the holder 612, and Figure 9(b) is a perspective view showing the connector 616 attached to the holder 612. As shown in Figure 9(a), the connector 616 is attached to one end of the holder 612 in the +Y direction, from one side in the short direction (X direction) of the heater 611 to the other side. That is, the connector 616 is attached to the holder 612 in the +X direction. The width direction of the connector 616 is the same direction as the longitudinal direction of the heater 611, i.e., the Y direction, when the connector 616 is attached to the holder 612.

[0032] The connector 616 has a housing 904 and an arm portion 905 made from a non-conductive material such as resin, and a contact 906 made from a conductive material such as metal. A claw portion 907 is attached to the arm portion 905.

[0033] As shown in Figure 9(b), the housing 904 has a shape that, when the connector 616 is mounted on the holder 612, sandwiches one end of the holder 612 in the longitudinal direction (Y direction) and one end of the heater 611 in the longitudinal direction (Y direction). The housing 904 has a first side surface 904A and a second side surface 904B that extend intersecting in the Y direction, and a first extension portion 904C and a second extension portion 904D that extend in the +X direction toward the heater 611 from the first side surface 904A and the second side surface 904B.

[0034] As shown in Figures 9(a) and 9(b), the arm portion 905 is located downstream of the housing 904 in the +Z direction, which is perpendicular to the mounting direction of the connector 616 (+X direction), and extends in the mounting direction of the connector 616 (+X direction). The arm portion 905 is provided near the center of the connector 616 in the width direction (Y direction) of the connector 616. One end of the arm portion 905 in the mounting direction is connected to the housing 904, and the other end is designed to bend elastically in a direction toward the housing 904.

[0035] As shown in Figures 9(a) and 9(b), the claw portion 907 is formed to protrude away from the housing 904 from near the center of the arm portion 905 in the mounting direction (+X direction). The claw portion 907 has a rising surface 907a that rises in the +Z direction away from the housing 904, and an inclined surface 907b provided downstream of the rising surface 907a in the +X direction. The inclined surface 907b is formed to approach the arm portion 905 as it moves toward the +X direction, which is the mounting direction of the connector 616.

[0036] [Holder wall] The holder 612 further includes a pair of wall portions 908, a connecting wall portion 909, and a connecting portion 910 that connects the pair of wall portions 908. The pair of wall portions 908, the connecting wall portion 909, and the connecting portion 910 are integrally formed at the end of the holder 612 in the +Y direction.

[0037] The pair of wall portions 908 are a pair of walls facing each other in the Y direction, which is perpendicular to the mounting direction (+X direction) of the connector 616. The pair of wall portions 908 are provided so as to sandwich the connector 616 when the connector 616 is mounted on the holder 612. In the longitudinal direction (Y direction) of the heater 611, the distance between the pair of wall portions 908 is slightly greater than the length of the connector 616 in the width direction (Y direction). The pair of wall portions 908 consists of a wall portion 908A as a first wall portion and a wall portion 908B as a second wall portion, which is positioned downstream of wall portion 908A in the -Y direction. When the connector 616 is mounted on the holder 612, wall portion 908A faces the first side surface 904A of the housing 904, and wall portion 908B faces the second side surface 904B of the housing 904.

[0038] The connecting wall portion 909 is a wall that connects the downstream ends of a pair of wall portions 908 (908A, 908B) in the mounting direction (+X direction).

[0039] The connecting portion 910 is provided to connect the upstream ends of the pair of wall portions 908 in the mounting direction (+X direction). In addition, a retaining portion 911 that functions as a retainer for the connector 616 is provided near the center of the connecting portion 910 in the Y direction. That is, the retaining portion 911, which serves as the first retaining portion, is integrally molded into the holder 612.

[0040] As shown in Figure 9(b), when the connector 616 is mounted on the holder 612, the arm portion 905 elastically bends to approach the housing 904. At this time, the inclined surface 907b of the claw portion 907 provided on the arm portion 905 rubs against the lower surface of the connecting portion 910. Then, when the connector 616 is mounted on the holder 612, the arm portion 905 elastically returns to its original position, and the claw portion 907 contacts the retaining portion 911 of the holder 612. At this time, the retaining portion 911 engages with the rising surface 907a of the claw portion 907, thereby restricting the connector 616 from moving upstream in the mounting direction, i.e., in the -X direction.

[0041] Furthermore, the housing 904 is configured such that the first extension 904C clamps one longitudinal end of the heater 611, and the second extension 904D clamps one longitudinal end of the holder 612, via the contact 906.

[0042] When removing the connector 616 from the holder 612, the operator presses the arm portion 905 downward to cause elastic deformation. This releases the engagement between the rising surface 907a of the claw portion 907 and the retaining portion 911, allowing the connector 616 to be moved in the removal direction (-X direction) opposite to the mounting direction. This allows the connector 616 to be removed from the holder 612.

[0043] [Explanation of U-shaped contact lenses] Figure 10 is a cross-sectional view showing the holder 612 and contact 906 perpendicular to the Y direction. As shown in Figure 10, inside the connector 616, the contact 906 has a U-shape when viewed from the longitudinal direction. The contact 906 has a spring pressure surface 912 as a first part and a pressure receiving surface 913 as a second part, which face each other in the Z direction.

[0044] The spring pressure surface 912 is positioned downstream of the pressure receiving surface 913 in the -Z direction and, with spring pressure, is in contact with the electrodes 903a and 903b for the heating resistor of the heater 611. The pressure receiving surface 913 is configured to receive the pressure applied by the spring pressure surface 912 to the heater 611 via the holder 612. In other words, the contact 906 is configured to sandwich the heater 611 and the holder 612 between the spring pressure surface 912 and the pressure receiving surface 913, and this configuration fixes the position of the contact 906 and the holder 612 so that they do not move even if they are affected by external disturbances. Furthermore, the spring pressure surface 912 and the pressure receiving surface 913 are formed from a single integrated member, and the contact 906 has a U-shape when viewed from the longitudinal direction.

[0045] [Effects of Example 1] According to Embodiment 1 described above, the positional relationship between the contact 906, the housing 904 of the connector 616, and the holder 612 can be fixed. The positional relationship between the housing 904 and the holder 612 is fixed by the engagement of the claw portion 907 and the retaining portion 911. The positional relationship between the contact 906 and the holder 612 is fixed by the configuration in which the spring pressure surface 912 of the U-shaped contact 906 and the pressure receiving surface 913, which is integrated with the spring pressure surface 912, sandwich the heater 611 and the holder 612. This configuration makes it difficult for the contact 906 to come off the holder 612.

[0046] Furthermore, if the connector 616 shifts relative to the heater 611, there is a risk that the spring pressure surface 912 of the contact 906 may detach from the electrodes 903a and 903b. However, according to Embodiment 1, with respect to the short-side direction (X direction) of the heater 611, the center line 903c of electrode 903a and the center line 903d of electrode 903b are located upstream of the center line c1 of the heater 611 in the mounting direction (+X direction) of the connector 616. In addition, since the claw portion 907 is engaged with the retaining portion 911, the shifting of the connector 616 upstream of the heater 611 in the mounting direction (+X direction) of the connector 616 is restricted. Therefore, it is possible to suppress the detachment of the spring pressure surface 912 of the contact 906 from the electrodes 903a and 903b. Furthermore, the connecting wall portion 909 of the holder 612 restricts the shifting of the connector 616 downstream of the heater 611 in the mounting direction of the connector 616. Therefore, it is possible to prevent the spring pressure surface 912 of the contact 906 from coming off the electrodes 903a and 903b.

[0047] In this embodiment, the holder 612 and the retaining portion 911 are not integrally molded but are separate parts, and when the holder 612 and the retaining portion 911 are engaged, there is a possibility that the positions of the holder 612 and the retaining portion 911 may be misaligned. Since the connector 616 engages with the retaining portion 911, if the positions of the holder 612 and the retaining portion 911 are misaligned, the positions of the connector 616 and the holder 612 will also be misaligned. This causes the contact position between the spring pressure surface 912 and the electrodes 903a and 903b to be misaligned. However, in this embodiment, the holder 612 and the retaining portion 911 are integrally molded. This reduces the effect of the misalignment of the contact position between the spring pressure surface 912 and the electrodes 903a and 903b caused by the misalignment of the holder 612 and the retaining portion 911 as described above.

[0048] <Example 2> Next, Embodiment 2 of the present invention will be described. Embodiment 2 is modified by adding a retaining portion 917 and a projection 914 to the housing 904 and contact 906 of Embodiment 1, respectively. For this reason, the same configuration as in Embodiment 1 will be omitted from the illustration or will be described using the same reference numerals in the illustration.

[0049] Figure 11(a) is a cross-sectional view showing the holder 612 and contact 906 perpendicular to the Z direction. Figure 11(b) is a cross-sectional view showing the holder 612 and contact 906 perpendicular to the Y direction. As shown in Figures 11(a) and (b), the contact 906 of the connector 1616 as a power supply connector according to Embodiment 2 is mounted on the housing 904 after the power supply cable 915 is crimped by the crimping portion 916. The housing 904 is provided with a retaining portion 917 as a second retaining portion, and the retaining portion 917 has a plurality (four in this embodiment) of grooves 917a formed therein.

[0050] The contact 906 is provided with multiple (four in this embodiment) projections 914 that can engage with multiple grooves 917a of the retaining portion 917. The engagement of the projections 914 of the contact 906 with the grooves 917a of the retaining portion 917 prevents the contact 906 from coming loose from the housing 904 in the removal direction (-X direction) opposite to the mounting direction (+X direction) after it has been mounted in the housing 904. The projections 914 are positioned approximately in the center of the contact 906 in the Z direction to prevent the contact 906 from tilting within the housing 904. Furthermore, the grooves 917a and projections 914 of the retaining portion 917 extend in the X direction and engage with each other in the Y direction as well. Therefore, the position of the contact 906 relative to the housing 904 in the Y direction is also determined. In this embodiment, the retaining portion 917 was provided with four grooves 917a and four projections 914, but this is not limited to this configuration. For example, the grooves 917a and projections 914 may each be 1 to 3 or 5 or more.

[0051] Furthermore, in order to miniaturize the connector 1616, the retaining portion 917 is positioned upstream in the mounting direction (+X direction) from the portion where the claw portion 907 and the retaining portion 911, as shown by line c2, engage. In other words, when the connector 1616 is mounted on the holder 612 and viewed in the longitudinal direction (Y direction), the retaining portion 917 is located upstream of the retaining portion 911 in the mounting direction (+X direction). Moreover, extending the contact 906 further upstream in the mounting direction (+X direction) than necessary would lead to an increase in the size of the contact 906. For this reason, it is desirable to position the projection 914 of the contact 906 downstream in the mounting direction (+X direction) from the crimping portion 916 that crimps the power supply cable 915, as shown by line c3.

[0052] [Effects of Example 2] According to Embodiment 2 described above, the contact 906, which is attached to the housing 904 of the connector 1616, is fixed to the housing 904 by the engagement of the retaining portion 917 of the housing 904 with the projection 914 of the contact 906. Therefore, the positional relationship between the contact 906, the housing 904, and the holder 612 can be fixed more firmly than in Embodiment 1.

[0053] <Other examples> In the embodiments described above, the second surface 611b of the heater 611 was in direct contact with the inner circumferential surface 614a of the belt 614, but this is not limited to that. For example, the heater 611 may be in contact with the belt 614 via a sheet material with high thermal conductivity, such as an iron alloy or aluminum. Even if such a sheet material is provided between the heater 611 and the belt 614, the pressurizing rotating body 62 still sandwiches the belt 614 together with the heater 611.

[0054] Furthermore, although a belt 614 was provided on the heating unit 61 in the embodiments described above, an endless film may be applied instead of the belt 614. Also, the fuser 6 may be configured such that the heating unit 61 applies pressure to the pressurizing rotating body 62, or the pressurizing rotating body 62 applies pressure to the heating unit 61.

[0055] Summary of this disclosure This disclosure includes at least the following: (Composition 1) A cylindrical fixing belt, A heater comprising a plate-shaped substrate, a heating resistor provided on the substrate, and an electrode electrically connected to the heating resistor and provided at the end of the substrate in the longitudinal direction of the substrate, wherein the heater is disposed in the internal space of the fixing belt, A holder is provided in the internal space of the fixing belt and holds the heater along its longitudinal direction, A power supply connector for supplying power to the heater, the power supply connector having a conductive contact that contacts the electrode and a housing that accommodates the contact, It has, In a fixing device that fixes a toner image formed on a recording material to the recording material using the heat of the heater via the fixing belt, The holder has an integrally molded retaining portion to prevent the power supply connector from coming off the heater. The contact has a first portion that contacts the electrode and a second portion that, together with the first portion, sandwiches the heater and the holder, and has a U-shape when viewed in the longitudinal direction. A fixing device characterized by the following features. (Configuration 2) The housing has a first side surface and a second side surface intersecting the longitudinal direction, The holder has a first wall portion facing the first side surface and a second wall portion facing the second side surface, When the power supply connector is attached to the holder, the power supply connector is positioned between the first wall and the second wall of the holder. The fixing device according to configuration 1, characterized by the above. (Composition 3) The holder has a connecting portion that connects the first wall portion and the second wall portion and is provided with the retaining portion. The fixing device according to configuration 2, characterized in that... (Composition 4) If the retaining portion of the holder is considered the first retaining portion, the housing has a second retaining portion to prevent the contact from coming out of the housing toward the upstream side in the mounting direction of the power supply connector. When the power supply connector is mounted on the holder and viewed in the longitudinal direction, the second retaining portion is located upstream of the first retaining portion in the mounting direction. The fixing device according to configuration 3, characterized by the above. (Composition 5) The contact is provided with a crimping section for crimping a power supply cable connected to the contact. The second retaining portion is located downstream of the crimping portion in the mounting direction of the power supply connector, The fixing device according to configuration 4, characterized by the features described above. (Composition 6) The heater is such that the first center line in the short-side direction of at least one of the electrodes is located upstream of the second center line in the short-side direction of the substrate in the direction in which the power supply connector is attached. A fixing device according to any one of configurations 1 to 5, characterized by the above. [Explanation of symbols]

[0056] 6: Fixing device (fuser) / 611: Heater / 612: Holder / 614: Fixing belt (belt) / 616, 1616: Power supply connector (connector) / 900: Circuit board / 901a, 901b: Heating resistor / 903a, 903b: Electrode / 903c: First center line (center line) / 904: Housing / 904A: First side / 904B: Second side / 906: Contact / 908A: First wall (wall) / 908B: Second wall (wall) / 910: Connection part / 911: Retaining part, first retaining part / 912: First part (spring pressure surface) / 913: Second part (pressure receiving surface) / 917: Retaining part (second retaining part) / c1: Second center line (center line) / +X: Mounting direction (direction)

Claims

1. A cylindrical fixing belt, A heater comprising a plate-shaped substrate, a heating resistor provided on the substrate, and an electrode electrically connected to the heating resistor and provided at the end of the substrate in the longitudinal direction of the substrate, wherein the heater is disposed in the internal space of the fixing belt, A holder is provided in the internal space of the fixing belt and holds the heater along its longitudinal direction, A power supply connector for supplying power to the heater, the power supply connector having a conductive contact that contacts the electrode and a housing that accommodates the contact, It has, In a fixing device that fixes a toner image formed on a recording material to the recording material using the heat of the heater via the fixing belt, The holder has an integrally molded retaining portion to prevent the power supply connector from coming off the heater. The contact has a first portion that contacts the electrode and a second portion that, together with the first portion, sandwiches the heater and the holder, and has a U-shape when viewed in the longitudinal direction. A fixing device characterized by the following features.

2. The housing has a first side surface and a second side surface that intersect the longitudinal direction, The holder has a first wall portion facing the first side surface and a second wall portion facing the second side surface, When the power supply connector is attached to the holder, the power supply connector is positioned between the first wall and the second wall of the holder. The fixing device according to feature 1.

3. The holder has a connecting portion that connects the first wall portion and the second wall portion and is provided with the retaining portion. The fixing device according to feature 2.

4. If the retaining portion of the holder is considered the first retaining portion, the housing has a second retaining portion to prevent the contact from coming off the housing toward the upstream side in the mounting direction of the power supply connector. When the power supply connector is mounted on the holder and viewed in the longitudinal direction, the second retaining portion is located upstream of the first retaining portion in the mounting direction. The fixing device according to feature 3.

5. The contact is provided with a crimping section for crimping a power supply cable connected to the contact. The second retaining portion is located downstream of the crimping portion in the mounting direction of the power supply connector, The fixing device according to feature 4.

6. The heater is such that the first center line in the short-side direction of at least one of the electrodes is located upstream of the second center line in the short-side direction of the substrate in the direction in which the power supply connector is attached. The fixing device according to any one of claims 1 to 5.

Images