JP2015011142A - Fixing device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support member which has a sufficient strength, a small dimension error, and a low manufacturing cost.SOLUTION: A fixing device 19 includes a fixing belt 21, a pressure member 22 coming into press-contact with the fixing belt 21, a pressing member 25 pressing the fixing belt 21 to the side of the pressure member 22, and a support member 24 supporting the pressing member 25. The support member 24 includes an attachment part 40 to which the pressing member 25 is attached, a first bent part 41 bent to the side away from the pressure member 22 from one end of the attachment part 40, a second bent part 42 bent to the side away from the pressure member 22 from the other end of the attachment part 40, a third bent part 43 bent to the side close to the second bent part 42 from the top end of the first bent part 41, and a fourth bent part 44 bent to the side close to the pressure member 22 from the top end of the third bent part 43.

Description

  The present invention relates to a fixing device that fixes a toner image on a recording medium, and an image forming apparatus including the fixing device.

  2. Description of the Related Art Conventionally, electrophotographic image forming apparatuses such as copying machines and printers include a fixing device that fixes a toner image onto a recording medium such as paper. For this fixing device, a “heat roller method” is widely used from the viewpoint of thermal efficiency and safety. The hot roller method is a method of forming a fixing nip using a pair of rollers. On the other hand, in recent years, the “belt method” has attracted attention due to demands for shortening the warm-up time and energy saving. The belt method is a method of forming a fixing nip using a fixing belt.

  For example, Patent Document 1 discloses a fixing belt, a pressure member that presses against the fixing belt and forms a fixing nip between the fixing belt (see “Pressure Roll 62” in Patent Document 1), and a fixing belt. A fixing device that includes a pressing member that presses the pressing member (see “Pressing pad 63” in Patent Document 1) and a support member that supports the pressing member (see “Holder 65” in Patent Document 1) is disclosed. Has been.

  In the fixing device having such a configuration, when the strength of the support member is low, the pressing member is bent, and the pressure distribution in the fixing nip becomes uneven. Therefore, in Patent Document 1, the strength of the support member is increased by forming a support member by laser welding three sheets of metal.

JP 2011-022473 A

  However, when forming a support member by welding a plurality of sheet metals as described above, when each sheet metal is thermally deformed, the pressure distribution in the fixing nip becomes non-uniform due to the difference in thermal expansion coefficient of each sheet metal, The support member may be damaged. Further, even at room temperature when each sheet metal is not thermally deformed, the dimensional error of the entire support member may increase due to variations in the dimensions of each sheet metal. Further, by welding each sheet metal, each sheet metal may be deformed. Further, in addition to the need for a jig for welding each sheet metal, the number of man-hours is increased by adding a welding process, and the manufacturing cost of the support member is increased.

  In view of the above circumstances, an object of the present invention is to provide a support member having sufficient strength, small dimensional error, and low manufacturing cost.

  The fixing device of the present invention includes a fixing belt, a pressure member that presses against the fixing belt and forms a fixing nip between the fixing belt, an inner side of the fixing belt, and the fixing belt is attached to the fixing belt. A pressure member that presses against the pressure member; and a support member that is provided inside the fixing belt and supports the pressure member. The support member includes an attachment portion to which the pressure member is attached; and the attachment portion. A first bent portion bent from the one end of the mounting portion to the side away from the pressure member, a second bent portion bent from the other end of the mounting portion to the side away from the pressure member, A third bent portion bent toward the side close to the second bent portion from the distal end portion of the first bent portion; and a first bent portion bent toward the side adjacent to the pressure member from the distal end portion of the third bent portion. And 4 bent portions.

  By adopting such a configuration, it is possible to form a support member having sufficient strength to support the pressing member by bending one sheet metal. Accordingly, it is possible to reduce the dimensional error of the entire support member as compared with the case where the support member is formed by welding a plurality of sheet metals. Moreover, since a jig for welding a plurality of sheet metals is not required and the welding process can be eliminated, the manufacturing cost of the support member can be reduced.

  The support member includes a fifth bent portion that is bent from a tip portion of the second bent portion to a side close to the first bent portion, and a side that is close to the pressure member from a tip portion of the fifth bent portion. It may be further provided with a sixth bent portion that is bent at a distance and faces the fourth bent portion with a gap.

  By adopting such a configuration, it is possible to evenly distribute the stress applied to the attachment portion to the first bent portion side and the second bent portion side.

  A convex or concave reinforcing portion may be provided on at least one of the first bent portion and the second bent portion.

  By adopting such a configuration, the strength of the support member can be further increased.

  A mounting member attached to the support member is further provided, and at least one of the first bent portion and the second bent portion has a protrusion or a hole for positioning the mounted member with respect to the support member May be provided.

  By adopting such a configuration, the attached member can be accurately positioned with respect to the support member.

  The support member may be formed by bending a single sheet metal by roll forming.

  Thus, it becomes easy to shape | mold a support member by using a roll forming process.

  The fourth bent portion may be opposed to the first bent portion with an interval.

  By adopting such a configuration, the length of the third bent portion connecting the first bent portion and the fourth bent portion can be increased, and the third bent portion can be used as a guide surface of a member attached to the support member. Part can be used.

  The fourth bent portion may be in contact with the first bent portion.

  By adopting such a configuration, it is possible to shorten the length of the third bent portion that connects the first bent portion and the fourth bent portion, and accordingly, it is necessary to mold the support member. The length of the sheet metal can also be shortened. Therefore, the manufacturing cost of the support member can be further reduced.

  The support member may have a U-shaped portion constituted by the first bent portion, the third bent portion, and the fourth bent portion.

  By adopting such a configuration, the strength of the support member can be increased.

  The image forming apparatus of the present invention includes any one of the fixing devices described above.

  According to the present invention, it is possible to provide a support member having sufficient strength, small dimensional error, and low manufacturing cost.

1 is a schematic diagram illustrating an outline of a configuration of a color printer according to an embodiment of the present invention. 1 is a cross-sectional view illustrating a fixing device of a color printer according to an embodiment of the present invention. 1 is a perspective view showing a fixing device of a color printer according to an embodiment of the present invention. 1 is a perspective view illustrating a state where a fixing belt, a magnetic shielding plate, and a guide plate are removed in a fixing device of a color printer according to an embodiment of the present invention. FIG. 3 is a perspective view showing a support member in the fixing device of the color printer according to the embodiment of the present invention. FIG. 3 is a front view showing a support member in the fixing device of the color printer according to the embodiment of the present invention. It is a front view which shows a supporting member in the fixing device of the color printer which concerns on another different embodiment. (A) is sectional drawing which shows the supporting member in which the convex-shaped reinforcement part was formed in the fixing device of the color printer which concerns on another different embodiment. (B) is sectional drawing which shows the supporting member in which the concave-shaped reinforcement part was formed in the fixing device of the color printer which concerns on another different embodiment.

  First, the overall configuration of the color printer 1 (image forming apparatus) will be described with reference to FIG.

  The color printer 1 includes a box-shaped printer main body 2, a paper feed cassette 3 that stores paper (recording medium) is provided in the lower part of the printer main body 2, and a paper discharge tray is provided in the upper part of the printer main body 2. 4 is provided.

  An intermediate transfer belt 6 is installed between a plurality of rollers in the center of the printer main body 2, and an exposure device 7 composed of a laser scanning unit (LSU) is disposed below the intermediate transfer belt 6. Yes. Below the intermediate transfer belt 6, four image forming units 8 are provided for each toner color (for example, four colors of magenta, cyan, yellow, and black). Each image forming unit 8 is rotatably provided with a photosensitive drum 9, and around the photosensitive drum 9, a charger 10, a developing unit 11, a primary transfer unit 12, and a cleaning device 13 are provided. The static eliminator 14 is arranged in the order of the primary transfer process. Above the developing unit 11, a toner container 15 corresponding to each image forming unit 8 is provided for each toner color (for example, four colors of magenta, cyan, yellow, and black).

  A paper transport path 16 is provided on one side (right side in the drawing) of the printer body 2. A paper feed unit 17 is provided at the upstream end of the conveyance path 16, and a secondary transfer unit 18 is provided at one end (right end in the drawing) of the intermediate transfer belt 6 at a middle portion of the conveyance path 16, downstream of the conveyance path 16. A fixing device 19 is provided in the section, and a paper discharge port 20 is provided at the downstream end of the transport path 16.

  Next, an image forming operation of the color printer 1 having such a configuration will be described. When the color printer 1 is turned on, various parameters are initialized, and initial settings such as temperature setting of the fixing device 19 are executed. When image data is input from a computer or the like connected to the color printer 1 and an instruction to start printing is given, an image forming operation is executed as follows.

  First, after the surface of the photosensitive drum 9 is charged by the charger 10, an electrostatic latent image is formed on the surface of the photosensitive drum 9 by laser light (see arrow P) from the exposure device 7. Next, the electrostatic latent image is developed into a toner image of a corresponding color by the developing device 11 with the toner supplied from the toner container 15. This toner image is primarily transferred to the surface of the intermediate transfer belt 6 in the primary transfer portion 12. Each image forming unit 8 sequentially repeats the above operation, whereby a full-color toner image is formed on the intermediate transfer belt 6. The toner and charge remaining on the photosensitive drum 9 are removed by the cleaning device 13 and the static eliminator 14, respectively.

  On the other hand, the paper taken out from the paper feed cassette 3 or the hand tray (not shown) by the paper feed unit 17 is conveyed to the secondary transfer unit 18 in synchronization with the above-described image forming operation, and is subjected to secondary transfer. In the portion 18, the full-color toner image on the intermediate transfer belt 6 is secondarily transferred to the paper. The sheet on which the toner image has been secondarily transferred is conveyed downstream in the conveyance path 16 and enters the fixing device 19, where the toner image is fixed on the sheet. The sheet on which the toner image is fixed is discharged from the discharge port 20 onto the discharge tray 4.

  Next, the fixing device 19 will be described. Hereinafter, for convenience of explanation, the front side in FIG. 2 is defined as the front side (front side) of the fixing device 19. An arrow Fr attached to FIGS. 3 to 5 indicates the front side (front side) of the fixing device 19.

  As shown in FIG. 2, the fixing device 19 includes a fixing belt 21, a pressure roller 22 (pressure member) provided on the right side of the fixing belt 21, and an IH fixing unit 23 provided on the left side of the fixing belt 21. The supporting member 24 provided inside the fixing belt 21, the pressing pad 25 (pressing member) provided inside the fixing belt 21 and supported by the supporting member 24, the inside of the fixing belt 21 and the left side of the supporting member 24. A pair of front and rear temperature sensors 26a and 26b (only the rear temperature sensor 26b is shown in FIG. 2), a magnetic shielding plate 27 provided inside the fixing belt 21 and on the left side of the temperature sensors 26a and 26b, And a guide plate 28 provided on the inner side of the fixing belt 21 and on the left side of the magnetic shielding plate 27.

  2 and 3, the fixing belt 21 is an endless belt and has a substantially cylindrical shape that is long in the front-rear direction. As shown in FIG. 2, the fixing belt 21 is configured to rotate in the rotation direction X (in this embodiment, counterclockwise when viewed from the front).

  The fixing belt 21 includes, for example, a base material layer, an elastic layer provided around the base material layer, and a release layer that covers the elastic layer. The base material layer of the fixing belt 21 is formed by, for example, plating or rolling a metal such as nickel or copper. The elastic layer of the fixing belt 21 is made of, for example, silicon rubber. The release layer of the fixing belt 21 is formed of a fluorine resin such as PFA, for example. In each figure, each layer (base material layer, elastic layer, release layer) of the fixing belt 21 is displayed without being particularly distinguished.

  The pressure roller 22 has a substantially cylindrical shape that is long in the front-rear direction. As shown in FIG. 2, the pressure roller 22 is in pressure contact with the fixing belt 21, and forms a fixing nip 30 with the fixing belt 21.

  The pressure roller 22 includes, for example, a cylindrical core member 31, an elastic layer 32 provided around the core member 31, and a release layer (not shown) that covers the elastic layer 32. ing.

  The core material 31 of the pressure roller 22 is formed of a metal such as stainless steel or aluminum. As shown in FIG. 3 and the like, bearings 33 a and 33 b are attached to both front and rear ends of the core material 31 of the pressure roller 22. Each bearing 33a, 33b is attached to a fixing frame (not shown). Thereby, as FIG. 2 shows, the pressurization roller 22 can be rotated in the rotation direction Y (this embodiment is clockwise by the front view).

  As shown in FIG. 3 and the like, a drive gear 34 is fixed to the rear end portion of the core 31 of the pressure roller 22 further to the rear side than the rear bearing 33b. The drive gear 34 is connected to a drive motor 37 (drive source). The pressure roller 22 is configured to rotate integrally with the drive gear 34 by the drive motor 37 rotating the drive gear 34. The elastic layer 32 of the pressure roller 22 is formed of, for example, silicon rubber or silicon sponge. The release layer of the pressure roller 22 is formed of, for example, a fluorine resin such as PFA.

  As shown in FIGS. 2 and 3, the IH fixing unit 23 includes an IH (Induction Heating) coil 35 (heat source) provided in an arc along the outer periphery of the fixing belt 21, and the outer periphery of the IH coil 35. And an arch core 36 provided. That is, the fixing device 19 of this embodiment is an induction heating method (IH method). The IH fixing unit 23 is not shown in FIG.

  The IH coil 35 is disposed outside the fixing belt 21. As shown in FIG. 2, the IH coil 35 faces the fixing belt 21, and the fixing belt 21 generates heat by a magnetic field generated by the IH coil 35.

  The support member 24 is formed, for example, by bending a single sheet metal by roll forming. The roll forming process is a processing technique in which a sheet metal is bent by an array of roller-shaped molds (molding rolls). The support member 24 has a long shape in the front-rear direction.

  As shown in FIG. 4 and the like, the support member 24 is bent at a substantially right angle from the mounting portion 40 to the left side (side away from the pressure roller 22) from the upper end portion (one end portion) of the mounting portion 40. A first bent portion 41, a second bent portion 42 bent substantially at right angles from the lower end portion (other end portion) of the mounting portion 40 to the left side (side away from the pressure roller 22), and the first bent portion 41 A third bent portion 43 that is bent at a substantially right angle from the left end portion (tip portion) to the lower side (side adjacent to the second bent portion 42), and the right side of the third bent portion 43 (tip portion) from the lower end portion (tip portion). A fourth bent portion 44 bent substantially at right angles to the pressure roller 22 side and a substantially right angle from the left end portion (tip portion) of the second bent portion 42 to the upper side (side adjacent to the first bent portion 41). The fifth bent portion 45 bent to the right, and the right side from the upper end (tip) of the fifth bent portion 45 (the side close to the pressure roller 22) It includes a sixth bent portion 46 is bent substantially at right angles, to the.

  As shown in FIG. 5 and the like, a protrusion 40 a is formed on the upper portion of the attachment portion 40 toward the right side. A plurality of projections 40a (five in this embodiment) are formed at intervals in the front-rear direction. The protruding portion 40a is formed by cutting and raising a part of the mounting portion 40 toward the right side, and a window portion 40b for cutting is opened below the protruding portion 40a. Positioning holes 40 c for positioning the pressing pad 25 with respect to the support member 24 are formed in the front lower portion and the rear lower portion of the mounting portion 40, respectively. A hole 40 d is formed at the front end of the mounting portion 40.

  As shown in FIG. 5 and the like, the first bent portion 41 is provided with a protrusion 41a toward the upper side (side away from the second bent portion 42). A plurality of (for example, 10 to 20) protrusions 41a are provided at intervals in the front-rear direction. A pair of front and rear holes 41 b are provided in the rear portion of the first bent portion 41. The first bent portion 41 is provided with a fixing hole 41c at the formation interval of the protrusion 41a and the hole 41b. A plurality of (for example, 10 to 20) fixing holes 41c are provided at intervals in the front-rear direction. The fixing hole 41c has a smaller diameter than the hole 41b.

  As shown in FIG. 6 and the like, the second bent portion 42 is provided with a protrusion 42a toward the lower side (side away from the first bent portion 41). A plurality of (for example, 10 to 20) protrusions 42a are provided at intervals in the front-rear direction. The second bent portion 42 is provided with a hole and a fixing hole (both not shown) similar to the hole 41b and the fixing hole 41c of the first bent portion 41. The second bent portion 42 is provided substantially parallel to the first bent portion 41.

  The third bent portion 43 is provided substantially in parallel with the attachment portion 40. As shown in FIG. 4 and the like, notches 43 a are provided at both front and rear ends of the third bent portion 43.

  As shown in FIG. 6 and the like, the fourth bent portion 44 is provided substantially in parallel with the first bent portion 41 and the second bent portion 42. The 4th bending part 44 has opposed the 1st bending part 41 via the space | interval d1. The tip end portion (right end portion) of the fourth bent portion 44 is opposed to the attachment portion 40 with a distance d2.

  The fifth bent portion 45 is provided substantially parallel to the attachment portion 40 and the third bent portion 43. As shown in FIG. 4 and the like, notches 45 a are provided at both front and rear ends of the fifth bent portion 45.

  As shown in FIG. 6 and the like, the sixth bent portion 46 is provided substantially in parallel with the first bent portion 41, the second bent portion 42, and the fourth bent portion 44. The sixth bent portion 46 is opposed to the second bent portion 42 with an interval d3. The interval d3 is substantially the same as the interval d1 between the first bent portion 41 and the fourth bent portion 44. The tip end portion (right end portion) of the sixth bent portion 46 faces the attachment portion 40 with a distance d4. The interval d4 is substantially the same as the interval d2 between the distal end portion of the fourth bent portion 44 and the attachment portion 40. The interval d2 and the interval d4 are longer than the interval d1 and the interval d3. The sixth bent portion 46 is opposed to the fourth bent portion 44 with an interval d5. The interval d5 is longer than the interval d1 and the interval d3.

  With the configuration as described above, the support member 24 of the present embodiment is formed with six L-shapes as indicated by the dashed-dotted circles in FIG. Further, the support member 24 of the present embodiment has a U-shaped portion K1 (see FIG. 6) configured by the first bent portion 41, the third bent portion 43, and the fourth bent portion 44. . Further, the support member 24 of the present embodiment has a U-shaped portion K2 (see FIG. 6) configured by the second bent portion 42, the fifth bent portion 45, and the sixth bent portion 46. . That is, the support member 24 has two U-shaped portions.

  As shown in FIG. 4, a pair of front and rear brackets (attached members) 50 are attached to the support member 24. Each bracket 50 is made of, for example, a sheet metal. Each bracket 50 includes a mounting plate 51 extending in the horizontal direction and a fixing plate 52 bent downward from the left end of the mounting plate 51 and extending in the vertical direction.

  A pair of front and rear positioning holes 53 are provided in the mounting plate 51 of each bracket 50, and each positioning hole 53 is engaged with a protrusion 41 a provided in the first bent portion 41 of the support member 24. The bracket 50 is positioned with respect to the support member 24. The mounting plate 51 of each bracket 50 is provided with a mounting hole 54 between a pair of front and rear positioning holes 53, and the mounting hole 54 and a fixing hole 41 c provided in the first bent portion 41 of the support member 24. Each bracket 50 is fixed to the support member 24 by a fastening member (not shown) penetrating through the bracket. The fixing plate 52 of each bracket 50 is in contact with the third bent portion 43 and the fifth bent portion 45 of the support member 24.

  As shown in FIG. 2 and the like, a pressing pad support plate 55 is fixed to the lower surface (outer surface) of the second bent portion 42 of the support member 24. The right end portion of the pressing pad support plate 55 protrudes to the right side of the support member 24. As shown in FIG. 3 and the like, fixed pieces 56 are fixed to both front and rear ends of the support member 24. The fixed piece 56 is fixed to a fixing frame (not shown). A cutout 57 is formed in the fixed piece 56.

  As shown in FIG. 2 and the like, the pressing pad 25 has a substantially vertically long rectangular shape when viewed from the front. The pressing pad 25 has a long shape in the front-rear direction. The pressing pad 25 is attached to the right surface (outer surface) of the attachment portion 40 of the support member 24. The pressing pad 25 is sandwiched from above and below by a protrusion 40 a provided on the mounting portion 40 and a pressing pad support plate 55.

  The right side surface of the pressing pad 25 is in contact with the inner peripheral surface of the fixing belt 21 and presses the fixing belt 21 to the pressure roller 22 side (right side in the present embodiment). When the fixing belt 21 rotates, the fixing belt 21 slides with respect to the pressing pad 25 while the pressing pad 25 is stopped. The pressing pad 25 is in contact only with the right side portion (the portion on the fixing nip 30 side) of the inner peripheral surface of the fixing belt 21.

  As shown in FIG. 4, the temperature sensors 26 a and 26 b are fixed to the fixing plate 52 of each bracket 50. Wirings (not shown) are connected to the temperature sensors 26 a and 26 b, and the above wirings are connected to the outside of the fixing belt 21 through notches 57 provided in the respective fixing pieces 56 (see FIG. 3). To come out. Each temperature sensor 26a, 26b is in contact with the inner surface of the fixing belt 21, and can detect the temperature of the fixing belt 21.

  As shown in FIG. 2, the magnetic shielding plate 27 includes a side plate 60 that covers the left side of the support member 24, and upper and lower plates 61 a and 61 b that are bent from the upper and lower ends of the side plate 60 toward the right side. . The magnetic shielding plate 27 is fixed to the support member 24. The magnetic shielding plate 27 is made of a non-magnetic and highly conductive material such as oxygen-free copper. The magnetic shielding plate 27 prevents the magnetic field generated by the IH coil 35 from penetrating the support member 24.

  The guide plate 28 is provided so as to cover the magnetic shielding plate 27. The guide plate 28 is formed of, for example, a magnetic material, and has a function of heating the fixing belt 21 by generating heat by the action of a magnetic field generated by the IH coil 35. The guide plate 28 includes an upper attachment portion 62 attached to the upper plate 61a of the magnetic shielding plate 27, a lower attachment portion 63 attached to the lower plate 61b of the magnetic shielding plate 27, an upper attachment portion 62, and a lower attachment portion 63. And a bending portion 64 that curves in an arc shape toward the left side. The curved portion 64 is disposed along the left side portion of the inner peripheral surface of the fixing belt 21 and guides (stretches) the fixing belt 21 from the inside.

  In the above-described configuration, when fixing a toner image on a sheet, the fixing belt 21 is heated by the IH coil 35 and the pressure roller 22 is rotated by the drive motor 37 (arrow Y in FIG. 2). reference). When the pressure roller 22 rotates in this way, the fixing belt 21 in pressure contact with the pressure roller 22 is driven to rotate in the direction opposite to the pressure roller 22 (see arrow X in FIG. 2). In this state, when a sheet on which an unfixed toner image is formed passes through the fixing nip 30, the sheet and the toner image are heated and pressurized, and the toner image is fixed on the sheet.

  In the present embodiment, as described above, the support member 24 includes the attachment portion 40, the first bent portion 41, the second bent portion 42, the third bent portion 43, and the fourth bent portion 44. By adopting such a configuration, the support member 24 having sufficient strength to support the pressing pad 25 can be formed by bending a single sheet metal. Accordingly, it is possible to reduce the dimensional error of the entire support member 24 as compared with the case where the support member 24 is formed by welding a plurality of sheet metals. Moreover, since a jig for welding a plurality of sheet metals is not required and the welding process can be eliminated, the manufacturing cost of the support member 24 can be reduced.

  Further, when the support member 24 is formed by combining a plurality of sheet metals, when each sheet metal is thermally deformed, the pressure distribution in the fixing nip 30 becomes non-uniform due to the difference in thermal expansion coefficient of each sheet metal, or the support member. 24 may be damaged. However, in the present embodiment, since the support member 24 is formed by a single sheet metal, there is no problem due to the difference in the coefficient of thermal expansion of each sheet metal as described above.

  In addition, since the strength of the support member 24 is increased by bending the support member 24, it is not necessary to increase the thickness of the support member 24 in order to increase the strength of the support member 24. Therefore, the support member 24 can be thinned.

  Further, the support member 24 is provided with a fifth bent portion 45 and a sixth bent portion 46. By adopting such a configuration, the stress applied to the attachment portion 40 can be evenly distributed on the upper side (first bent portion 41 side) and the lower side (second bent portion 42 side).

  Further, the first bent portion 41 is provided with a protrusion 41 a for positioning each bracket 50 with respect to the support member 24. Therefore, each bracket 50 can be accurately positioned with respect to the support member 24.

  The support member 24 is formed by bending one sheet metal by roll forming. By using roll forming as described above, the support member 24 can be easily molded.

  In the present embodiment, the support member 24 has a U-shaped portion K1 (see FIG. 6) constituted by the first bent portion 41, the third bent portion 43, and the fourth bent portion 44. Therefore, the strength of the support member 24 can be increased. In the present embodiment, the support member 24 has a U-shaped portion K2 (see FIG. 6) configured by the second bent portion 42, the fifth bent portion 45, and the sixth bent portion 46. Therefore, the strength of the support member 24 can be further increased.

  Further, the fourth bent portion 44 faces the first bent portion 41 via the interval d1, and the sixth bent portion 46 faces the second bent portion 42 via the interval d3. By adopting such a configuration, the lengths of the third bent portion 43 and the fifth bent portion 45 can be increased, and the third bent portion 43 serves as a guide surface for each bracket 50 attached to the support member 24. And it becomes possible to utilize the 5th bending part 45 (refer FIG. 2).

  In the present embodiment, a case has been described in which the fourth bent portion 44 faces the first bent portion 41 via the interval d1, and the sixth bent portion 46 faces the second bent portion 42 via the interval d3. On the other hand, in another different embodiment, as shown in FIG. 7, the fourth bent portion is formed by bending the distal end portion of the first bent portion 41 and the distal end portion of the second bent portion 42 by so-called “hemming bending”. The portion 44 may be in contact with the first bent portion 41, and the sixth bent portion 46 may be in contact with the second bent portion 42. By adopting such a configuration, the lengths of the third bent portion 43 and the fifth bent portion 45 can be shortened, and accordingly, the length of the sheet metal necessary for molding the support member 24 is increased. It can also be shortened. Therefore, the manufacturing cost of the support member 24 can be further reduced.

  Although not particularly described in the present embodiment, at least one of the first bent portion 41 and the second bent portion 42 is provided with a convex reinforcing portion 71 as shown in FIG. It may be done. In addition, at least one of the first bent portion 41 and the second bent portion 42 may be provided with a concave reinforcing portion 72 as shown in FIG. 8B. By adopting such a configuration, the strength of the support member 24 can be further increased. The reinforcing part 71 and the reinforcing part 72 can be formed by, for example, drawing a sheet metal.

  In the present embodiment, the case where the support member 24 has two U-shaped portions has been described. However, in other different embodiments, one or three support members 24 are included in the U-shaped portion. You may have more than one.

  In the present embodiment, the brackets 50 are positioned with respect to the support member 24 by the protrusions 41a provided in the first bent portion 41. However, in other different embodiments, the holes 41b provided in the first bent portion 41 are used. A member to be attached such as the bracket 50 may be positioned with respect to the support member 24. Furthermore, in another different embodiment, a member to be attached such as the bracket 50 may be positioned with respect to the support member 24 by a protrusion 42 a or a hole (not shown) provided in the second bent portion 42.

  In the present embodiment, the bracket 50 is an attached member, but in other different embodiments, the temperature sensor 26, the magnetic shielding plate 27, and the guide plate 28 may be attached members.

  Although the case where the IH coil 35 is used as a heat source has been described in the present embodiment, a heater such as a halogen heater or a ceramic heater may be used as a heat source in another different embodiment.

  In the present embodiment, the case where the guide plate 28 has a function of heating the fixing belt 21 has been described. On the other hand, when using a heater instead of the IH coil 35 as a heat source, the guide plate 28 may not have a function of heating the fixing belt 21.

  In this embodiment, the case where the drive motor 37 (drive source) is connected to the pressure roller 22 has been described. However, in another different embodiment, the drive motor 37 may be connected to the fixing belt 21.

  In this embodiment, the case where the configuration of the present invention is applied to the color printer 1 has been described. However, in other different embodiments, the present invention is applied to other image forming apparatuses such as a monochrome printer, a copier, a facsimile machine, and a multifunction machine. A configuration may be applied.

1 Color printer (image forming device)
19 Fixing Device 21 Fixing Belt 22 Pressure Roller (Pressure Member)
24 support member 25 pressing pad (pressing member)
30 fixing nip 40 mounting portion 41 first bent portion 41a protrusion 41b hole 42 second bent portion 43 third bent portion 44 fourth bent portion 45 fifth bent portion 46 sixth bent portion 50 bracket (attached member)
71 (convex shaped) reinforcing part 72 (concave shaped) reinforcing part

Claims (9)

A fixing belt,
A pressure member that presses against the fixing belt to form a fixing nip with the fixing belt;
A pressing member provided inside the fixing belt and pressing the fixing belt toward the pressing member;
A support member provided inside the fixing belt and supporting the pressing member,
The support member is
An attachment portion to which the pressing member is attached;
A first bent portion bent from one end portion of the attachment portion to a side away from the pressure member;
A second bent portion bent from the other end portion of the mounting portion to the side away from the pressure member;
A third bent portion bent from the tip end portion of the first bent portion toward the side close to the second bent portion;
A fixing device, comprising: a fourth bent portion bent from a tip end portion of the third bent portion toward a side close to the pressure member. The support member is
A fifth bent portion bent from the tip end portion of the second bent portion toward the side close to the first bent portion;
6. A sixth bent portion bent from the tip of the fifth bent portion toward the side close to the pressure member and facing the fourth bent portion with an interval. Item 4. The fixing device according to Item 1.   The fixing device according to claim 1, wherein at least one of the first bent portion and the second bent portion is provided with a convex or concave reinforcing portion. A mounting member attached to the support member;
The projection or hole for positioning the said to-be-attached member with respect to the said supporting member is provided in at least any one of the said 1st bending part and the said 2nd bending part. The fixing device according to claim 1.   The fixing device according to claim 1, wherein the support member is formed by bending a single sheet metal by roll forming.   The fixing device according to claim 1, wherein the fourth bent portion is opposed to the first bent portion with an interval.   The fixing device according to claim 1, wherein the fourth bent portion is in contact with the first bent portion.   The said support member has a U-shaped part comprised by the said 1st bending part, the said 3rd bending part, and the said 4th bending part, The any one of Claims 1-7 characterized by the above-mentioned. The fixing device according to claim 1.   An image forming apparatus comprising the fixing device according to claim 1.

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