Fixing apparatus, Image forming apparatus

Abstract

The objective is to suppress variations in the position of the oscillating member between devices, compared to the case where the positioning member and the oscillating member are supported by different members. [Solution] The fixing device comprises a heating member for heating an image formed on a recording medium, a pressing member for sandwiching the recording medium between itself and the heating member and for pressurizing the recording medium toward the heating member, a pressing member for pressing the pressing member toward the heating member, an elastic member having one end attached to the pressing member and elastically deforming to generate a pressing force that causes the pressing member to press the recording medium toward the heating member, a swinging member to which the other end of the elastic member is attached and which is swingably supported by a support member, and the amount of elastic deformation of the elastic member is determined by the position in which it is swinging, and a positioning member that contacts the swinging member, determines the position of the swinging member and is supported by the support member.

Description

Technical Field

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

Background Art

[0002] The fixing device described in Patent Document 1 includes a heating roller and a pressure roller that rotate while contacting each other, a rotatable pressure lever that presses the pressure roller against the heating roller, a pressure plate that engages with the pressure lever, an opening / closing lever that rotates in conjunction with the opening / closing operation of an opening / closing cover, and a pressure spring interposed between the opening / closing lever and the pressure plate. In the fixing device that makes the pressure roller in a pressurized state or a pressure release state by rotating the opening / closing lever in conjunction with the opening / closing operation of the opening / closing cover to change the pressing force of the pressure spring, a cam that selectively contacts the pressure plate by rotating is provided, and the pressure plate is moved by the cam to reduce the pressing force of the pressure roller by the pressure spring.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The fixing device includes a heating member and a pressure member that presses a recording medium toward the heating member. Further, an elastic member for generating a pressing force for pressing the recording medium against the pressure member is provided. One end of this elastic member is attached to a pressing member that presses the pressure member toward the heating member, and the other end of the elastic member is attached to a swingable swing member. Furthermore, a positioning member that contacts the swing member to determine the position of the swing member is provided.

[0005] Conventionally, because the positioning member and the oscillating member were supported by different members, variations in assembly position during manufacturing caused the position of the oscillating member to vary between devices.

[0006] The object of this disclosure is to suppress variations in the position of the oscillating member between devices, compared to the case where the positioning member and the oscillating member are supported by different members. [Means for solving the problem]

[0007] A fixing apparatus according to a first aspect of the present disclosure is characterized by comprising: a heating member for heating an image formed on a recording medium; a pressing member for sandwiching the recording medium between itself and the heating member and for pressurizing the recording medium toward the heating member; a pressing member for pressing the pressing member toward the heating member; an elastic member, one end of which is attached to the pressing member and which elastically deforms to generate a pressing force that causes the pressing member to press the recording medium toward the heating member; a oscillating member, the other end of which is attached and which is supported by a support member so as to be oscillating, and the amount of elastic deformation of the elastic member is determined by the position in which it is oscillating; and a positioning member, which is in contact with the oscillating member, determines the position of the oscillating member and is supported by the support member.

[0008] A fixing device according to a second aspect of the present disclosure is a fixing device according to the first aspect, wherein the support member is a cylindrical shaft member that pivotably supports the rocking member and extends in the axial direction of the rocking member, and the positioning member is attached to and supported by the shaft member.

[0009] A fixing device according to a third aspect of the present disclosure is a fixing device according to the first aspect, characterized in that the positioning member is provided with a plurality of positioning parts that contact the oscillating member to determine the position of the oscillating member, and the oscillating member is positioned at a plurality of positions.

[0010] A fixing device according to a fourth aspect of the present disclosure is a fixing device according to the third aspect, wherein the support member is a cylindrical shaft member that pivotably supports the rocking member and extends in the axial direction of the rocking member, and the positioning portions are provided in a plurality of positions at different locations aligned in the axial direction, and the rocking member that is in contact with one of the positioning portions moves the positioning member along the shaft member in the axial direction, thereby separating from one of the positioning portions and contacting another of the positioning portions.

[0011] A fixing device according to a fifth aspect of the present disclosure is a fixing device according to the first aspect, wherein the support member supports the rocking member so as to be rockable and is a cylindrical shaft member extending in the axial direction of the rocking member, and is characterized in that, when viewed from the axial direction, the mounting portion to which the other end of the elastic member is attached on the rocking member and the contacted portion to which the positioning member contacts on the rocking member are on the same side with respect to the shaft member.

[0012] A fixing device according to a sixth aspect of the present disclosure is a fixing device according to a fifth aspect, wherein the oscillating member is biased to contact the positioning member by the elastic force of the elastic member, and the contacted portion is arranged on an arc with the axis of the shaft member as the center and the radius of the first distance, when viewed from the axial direction, the distance from the axis of the shaft member to the mounting portion is defined as the first distance.

[0013] An image forming apparatus according to a seventh aspect of this disclosure is characterized by comprising a forming unit for forming an image on a recording medium, and a fixing device according to any one of claims 1 to 6 for fixing the image formed on the recording medium by the forming unit onto the recording medium. [Effects of the Invention]

[0014] In the fixing device according to the first aspect of this disclosure, it is possible to suppress variations in the position of the oscillating member between devices, compared to the case in which the positioning member and the oscillating member are supported by different members.

[0015] In the fixing device according to the second aspect of this disclosure, the position of the oscillating member can be made less variable between devices compared to the case in which the oscillating member and the positioning member are attached to different positions on a plate-shaped frame.

[0016] In the fixing apparatus according to a third aspect of this disclosure, the pressure applied by the pressurizing member toward the heating member can be changed.

[0017] In the fixing device according to the fourth aspect of this disclosure, the oscillating member that contacts one positioning part can be brought into contact with other positioning parts with a simpler configuration compared to the case in which the oscillating member that contacts one positioning part is brought into contact with other positioning parts by attaching and detaching the positioning member to the support member.

[0018] In the fixing device according to the fifth aspect of this disclosure, compared to the case where the mounting portion and the contacted portion of the elastic member are arranged on opposite sides with the shaft member in between, the degree of freedom of the shape of the oscillating member on the side opposite to the mounting portion and the contacted portion of the elastic member with respect to the shaft member can be improved.

[0019] In the fixing device according to the sixth aspect of this disclosure, the position of the oscillating member can be made less variable between devices compared to the case where the arc with radius equal to a first distance, centered on the axis of the shaft member, and the contacted portion are separated when viewed from the axial direction.

[0020] In the image forming apparatus according to the seventh aspect of this disclosure, it is possible to suppress variations in the image fixing quality on the recording medium between apparatuses, compared to the case in which the fixing apparatus is equipped in which the oscillating member and the positioning member are supported by different members. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic diagram showing an image forming apparatus according to an embodiment of the present disclosure. [Figure 2] This is a schematic diagram showing a toner image forming unit provided in an image forming apparatus according to an embodiment of the present disclosure. [Figure 3]A fixing device according to an embodiment of the present disclosure, which is a front view showing a state of being disposed at a first swing position. [Figure 4] A fixing device according to an embodiment of the present disclosure, which is a perspective view showing a state of being disposed at a first swing position. [Figure 5] A fixing device according to an embodiment of the present disclosure, which is a front view showing a state of being disposed at a second swing position. [Figure 6] A fixing device according to an embodiment of the present disclosure, which is a perspective view showing a state of being disposed at a second swing position.

Embodiments for Carrying out the Invention

[0022] An example of a fixing device and an image forming apparatus according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 6. Note that an arrow H shown in each figure is in the vertical direction and indicates the vertical direction of the image forming apparatus. An arrow W is orthogonal to the arrow H and is in the horizontal direction, indicating the width direction of the system. An arrow D is orthogonal to the arrows H and W and is in the horizontal direction, indicating the depth direction of the image forming apparatus.

[0023] (Overall Configuration of Image Forming Apparatus 10) As shown in FIG. 1, an image forming apparatus 10 includes an image forming unit 12 that forms a toner image, and a conveyance unit 14 that conveys a sheet member P as a recording medium along a conveyance path 14a. Further, the image forming apparatus 10 includes a housing member 18 that houses the sheet member P.

[0024] In this configuration, in the image forming apparatus 10, the sheet member P housed in the housing member 18 by the conveyance unit 14 is conveyed along the conveyance path 14a. Further, a toner image is formed by the image forming unit 12 based on the input image data. Also, this toner image is formed on the sheet member P being conveyed, and the sheet member P on which the toner image is formed is discharged to the outside of the housing 10a.

[0025] 〔Image Forming Unit 12〕 As shown in Figure 1, the image forming unit 12 includes a plurality of toner image forming units 30, each forming a toner image of a different color, and a transfer unit 32 that transfers the toner images formed by the toner image forming units 30 to a sheet member P. Furthermore, the image forming unit 12 includes a fixing device 34 that fixes the toner images transferred to the sheet member P by the transfer unit 32 to the sheet member P.

[0026] -Toner image forming unit 30- Multiple toner image forming units 30 are provided to form toner images for each color. In this embodiment, toner image forming units 30Y, 30M, 30C, and 30K for a total of four colors—yellow (Y), magenta (M), cyan (C), and black (K)—are provided. In the following description, if it is not necessary to distinguish between yellow (Y), magenta (M), cyan (C), and black (K), the designations Y, M, C, and K will be omitted from the reference numerals.

[0027] Each toner image forming unit 30 is basically configured similarly, except for the toner used, and as shown in Figure 2, it includes a rotating cylindrical image holder 36 and a charger 42 for charging the image holder 36. Furthermore, the toner image forming unit 30 includes an exposure device 44 that irradiates the charged image holder 36 with exposure light to form an electrostatic latent image, and a developing device 46 that develops the electrostatic latent image as a toner image with a developer G containing toner. Thus, each toner image forming unit 30 is configured to form images of each color using toner of each color.

[0028] Furthermore, each colored image holder 36 is in contact with a circulating transfer belt 50 (details will be described later), as shown in Figure 1. In the circulating direction of the transfer belt 50 (see arrows in the figure), the toner image forming units 30 for yellow (Y), magenta (M), cyan (C), and black (K) are arranged in this order from the upstream side.

[0029] -Transfer section 32- As shown in Figure 1, the transfer unit 32 includes a transfer belt 50 and primary transfer rolls 52, each positioned on the opposite side of the image holders 36 of each color, with the transfer belt 50 in between. These primary transfer rolls 52 transfer the toner images formed on the image holders 36 of each color to the transfer belt 50.

[0030] Furthermore, the transfer section 32 includes a winding roll 56 around which the transfer belt 50 is wound, and a drive roll 58 around which the transfer belt 50 is wound and which transmits rotational force to the transfer belt 50. As a result, the transfer belt 50 rotates in the direction of the arrow in the figure.

[0031] Furthermore, the transfer unit 32 includes a secondary transfer roll 54 positioned on the opposite side of the winding roll 56, with the transfer belt 50 in between. The secondary transfer roll 54 is configured to transfer the toner image transferred to the transfer belt 50 to the sheet member P. A transfer nip NT is formed between the secondary transfer roll 54 and the transfer belt 50 to transfer the toner image to the sheet member P.

[0032] In this configuration, the toner image is first transferred to the transfer belt 50 by the primary transfer roll 52 in the order of yellow (Y), magenta (M), cyan (C), and black (K). The toner image is then transferred from the transfer belt 50 to the sheet member P, which is transported sandwiched between the transfer belt 50 and the secondary transfer roll 54, by the secondary transfer roll 54. The sheet member P, on which the toner image has been transferred, is then transported toward the fuser unit 34.

[0033] - Fixing device 34 - As shown in Figure 1, the fixing device 34 is positioned downstream of the transfer nip NT in the transport direction of the sheet member P. The fixing device 34 heats and pressurizes the toner image transferred to the sheet member P to fix it to the sheet member P. The fixing device 34 will be described in detail later.

[0034] [Conveying section 14] As shown in Figure 1, the transport unit 14 includes a delivery roll 20 that sends the sheet member P housed in the storage member 18 to the transport path 14a, and a prevention roll 22 that prevents double feeding of the sheet member P sent out by the delivery roll 20. Furthermore, the transport unit 14 includes an adjustment roll 24 that adjusts the timing of the sheet member P being sent to the transfer nip NT. The transport unit 14 also includes an discharge roll 26 that discharges the sheet member P, on which the toner image has been fixed by the fixing device 34, to the outside of the housing 10a.

[0035] 〔others〕 As shown in Figure 1, the housing 10a of the image forming apparatus 10 is provided with a maintenance door 11 that opens the fixing device 34 to the outside. The maintenance door 11 rotates around its shaft 11a and moves between a normal position (see solid line) and an open position (see dashed line) that opens the fixing device 34.

[0036] (Main part configuration) Next, the fixing device 34 will be described in detail.

[0037] As shown in Figures 3 and 5, the fixing device 34 includes a heating roll 62 having a heat source inside, and a pressure roll 64 that pressurizes the sheet member P being conveyed between the heating roll 62 toward the heating roll 62. The pressure roll 64 is positioned above the heating roll 62. The pressure roll 64 rotates in conjunction with the heating roll 62, which rotates by receiving a driving force from a drive source (not shown). The pressure roll 64 is an example of a pressurizing member. The heating roll 62 is an example of a heating member.

[0038] Furthermore, the fixing device 34 includes a pressurizing unit 60 for pressurizing the sheet member 64 against the heating roll 62 using a pressure roll 64. The pressurizing unit 60 includes a pressing member 70, a tension spring 74, a oscillating member 78, and a positioning member 82. The pressing member 70, tension spring 74, oscillating member 78, and positioning member 82 are provided in pairs in the depth direction with the pressure roll 64 in between. The pair of pressing member 70, tension spring 74, oscillating member 78, and positioning member 82 are symmetrical with respect to the pressure roll 64.

[0039] Furthermore, the oscillating member 78 is positioned by the positioning member 82 at a first oscillating position (see Figure 3) and a second oscillating position (see Figure 5). When the oscillating member 78 is positioned at the first oscillating position, the pressure applied by the pressure roll 64 to press the sheet member P toward the heating roll 62 (nip force) is the normal pressure used to clamp ordinary paper. On the other hand, when the oscillating member 78 is positioned at the second oscillating position, the pressure applied by the pressure roll 64 to press the sheet member P toward the heating roll 62 (nip force) is a lower pressure than the normal pressure. For example, when using an envelope or the like as the sheet member P, the pressure applied to the sheet member P toward the heating roll 62 is set to a lower pressure to suppress the formation of wrinkles in the envelope or the like.

[0040] In the following description, we will explain the pressing member 70, tension spring 74, oscillating member 78, and positioning member 82 located on the front side of the pressure roll 64 in the depth direction.

[0041] [Pressing member 70] As shown in Figures 3 and 5, the pressing member 70 is positioned to extend in the width direction so as to press from above the shaft portion 64a of the pressure roll 64 that protrudes in the depth direction. A shaft portion 70a is positioned at one end of the pressing member 70 on one side in the width direction (left side in the figures), extending in the depth direction, to pivotably support the pressing member 70. This shaft portion 70a is attached to a frame member (not shown).

[0042] Furthermore, the other end of the pressing member 70 on the other side in the width direction (right side in the figure) is positioned opposite one end of the shaft portion 70a, with the shaft portion 64a of the pressure roll 64 in between.

[0043] [Tension spring 74] The tension spring 74 is positioned to extend vertically, as shown in Figures 3 and 5. The upper end (one end) of the tension spring 74 is attached to the other end of the pressing member 70. The tension spring 74 is an example of an elastic member.

[0044] [Oscillating member 78] The oscillating member 78, positioned in the first oscillating position, is located on the opposite side of the shaft portion 70a of the pressing member 70, with the pressure roll 64 in between, as seen from the depth direction, as shown in Figure 3. The oscillating member 78 extends in the vertical direction. A cylindrical shaft member 80, which supports the oscillating member 78, is positioned at the lower end of the oscillating member 78 in the vertical direction, extending in the depth direction. This shaft member 80 is attached to a frame member (not shown). The shaft member 80 is an example of a support member.

[0045] Furthermore, the upper part of the oscillating member 78 relative to the shaft member 80 is provided with a bent portion 78a, and the upper part of the oscillating member 78 relative to the bent portion 78a is positioned outward in the depth direction (away from the pressure roll 64) relative to the lower part of the oscillating member 78 (see Figure 4).

[0046] As shown in Figure 5, the oscillating member 78 positioned at the second oscillating position is tilted in the vertical direction at a position obtained by oscillating counterclockwise around the shaft member 80 relative to the oscillating member 78 positioned at the first oscillating position.

[0047] Furthermore, the lower end (other end) of the tension spring 74 is attached to the lower end of the oscillating member 78. Specifically, the lower end of the tension spring 74 in a tensile state is attached to the mounting portion 78b of the oscillating member 78 at the portion of the oscillating member 78 that is lower to the shaft member 80.

[0048] In this configuration, the tensile force (elastic force) of the tension spring 74 applies a rotational force to the oscillating member 78, causing it to rotate counterclockwise around the shaft member 80. Furthermore, the tensile force generated by the elastic deformation of the tension spring 74 creates an additional pressure that causes the pressure roll 64 to press the sheet member P against the heating roll 62 via the pressing member 70.

[0049] Specifically, the amount of elastic deformation (elongation) of the tension spring 74 when the oscillating member 78 is positioned in the first oscillating position is greater than the amount of elastic deformation of the tension spring 74 when the oscillating member 78 is positioned in the second oscillating position. As a result, the pressure applied by the pressure roll 64 to the sheet member P when the oscillating member 78 is positioned in the first oscillating position is stronger than the pressure applied by the pressure roll 64 to the sheet member P when the oscillating member 78 is positioned in the second oscillating position.

[0050] [Positioning member 82] As shown in Figures 4 and 6, the positioning member 82 is supported by a shaft member 80 that extends in the depth direction. In other words, the positioning member 82 is supported by a member similar to the oscillating member 78.

[0051] Specifically, the positioning member 82 is integrally formed and has a support portion 84 supported by the shaft member 80, a first positioning portion 86, a second positioning portion 88, and a gripping portion 90. The first positioning portion 86 is an example of one positioning portion. The second positioning portion 88 is an example of another positioning portion.

[0052] The support portion 84 is located on the rear side (pressure roll 64 side) in the depth direction relative to the oscillating member 78. The support portion 84 has a circular through-hole 84a through which the shaft member 80 passes.

[0053] The first positioning portion 86 is located on the front side in the depth direction relative to the support portion 84, and on the other end side in the width direction (right side in the figure) relative to the lower end of the oscillating member 78. The first positioning portion 86 has a first contact portion 86a that contacts the lower end of the oscillating member 78 (see Figure 3). The part of the oscillating member 78 that contacts this first contact portion 86a is referred to as the contacted portion 78c. Thus, the contacted portion 78c and the mounting portion 78b are located on the same side relative to the shaft member 80.

[0054] Furthermore, as shown in Figure 3, when viewed from the depth direction, the distance from the axis of the shaft member 80 to the mounting portion 78b is defined as distance L1. With the first contact portion 86a in contact with the lower end of the oscillating member 78, the contacted portion 78c is positioned on an arc R1 with a radius of distance L1, centered on the axis of the shaft member 80. Distance L1 is an example of the first distance.

[0055] As shown in Figure 4, the second positioning section 88 is located on the other end in the width direction relative to the first positioning section 86, and on the front side in the depth direction relative to the first positioning section 86. In other words, the first positioning section 86 and the second positioning section 88 are aligned in the depth direction, which is the axial direction of the shaft member 80. Furthermore, the second positioning section 88 has a second contact section 88a that contacts the contacted portion 78c of the oscillating member 78 (see Figure 5). The second contact section 88a is an example of a contact section.

[0056] As mentioned above, the tensile force (elastic force) of the tension spring 74 applies a rotational force to the oscillating member 78, causing it to rotate counterclockwise around the shaft member 80. In other words, the tensile force (elastic force) of the tension spring 74 biases the oscillating member 78 to come into contact with the positioning member 82.

[0057] On the other hand, the gripping portion 90 is provided on the other side in the width direction relative to the support portion 84, and extends to the other side in the width direction with the support portion 84 as its base end.

[0058] In this configuration, the positioning member 82 is movable in the depth direction along the shaft member 80 by an operator gripping the gripping portion 90. The positioning member 82 moves to a first contact position (see Figures 3 and 4) where the first contact portion 86a of the first positioning portion 86 contacts the contacted portion 78c of the rocking member 78, and to a second contact position (see Figures 5 and 6) where the second contact portion 88a of the second positioning portion 88 contacts the contacted portion 78c of the rocking member 78. When the first contact portion 86a contacts the contacted portion 78c of the rocking member 78, the rocking member 78 is positioned in the first rocking position. When the second contact portion 88a contacts the contacted portion 78c of the rocking member 78, the rocking member 78 is positioned in the second rocking position.

[0059] Furthermore, the other positioning member 82, which is located on the opposite side of the pressure roll 64 in the depth direction, is connected to the first positioning member 82 via a mechanism (not shown) so that it moves in the same way as the first positioning member 82 moves in the depth direction. In this way, the pair of positioning members 82 move synchronously. Also, the synchronous movement of the pair of positioning members 82 causes the pair of oscillating members 78 to oscillate synchronously.

[0060] (action) Next, we will explain the function of the main components. With the positioning member 82 positioned at the first contact position, the first contact portion 86a of the first positioning portion 86 comes into contact with the contacted portion 78c of the oscillating member 78, as shown in Figures 3 and 4. As a result, the oscillating member 78 is positioned at the first oscillating position, and the pressure applied by the pressure roll 64 to press the sheet member P toward the heating roll 62 becomes the normal pressure.

[0061] Meanwhile, the worker moves the maintenance door 11 to the open position (see the dashed line in Figure 1). Furthermore, the worker grasps the gripping portion 90 of the positioning member 82 and moves the positioning member 82 toward the back in the depth direction along the shaft member 80. As a result, the positioning member 82 at the first contact position moves to the second contact position shown in Figures 5 and 6. As the positioning member 82 moves to the second contact position, the second contact portion 88a of the second positioning portion 88 comes into contact with the contacted portion 78c of the oscillating member 78. As a result, the oscillating member 78 is positioned at the second oscillating position, and the pressure applied by the pressure roll 64 to pressurize the sheet member P toward the heating roll 62 becomes a low pressure.

[0062] Furthermore, to move the swinging member 78, which is positioned at the second swinging position, to the first swinging position, the worker moves the maintenance door 11 to the open position (see the dashed line in Figure 1). Then, the worker grasps the upper part of the swinging member 78 as shown in Figure 5 and swings the swinging member 78. The worker then moves the swinging member 78 to a separation position (see the dashed line in Figure 5) where the contacted portion 78c of the swinging member 78 is separated from the second contact portion 88a of the second positioning portion 88, and fixes the swinging member 78 in that position with a locking member (not shown). In this state, the worker grasps the gripping portion 90 of the positioning member 82 and moves the positioning member 82 toward the back in the depth direction along the shaft member 80. As a result, the positioning member 82 at the second contact position moves to the first contact position as shown in Figures 3 and 4.

[0063] Furthermore, by unlocking the locked oscillating member 78, the oscillating member 78 oscillates, and the contacted portion 78c of the oscillating member 78 comes into contact with the first contact portion 86a of the first positioning portion 86. As a result, the oscillating member 78 is positioned in the first oscillating position, and the pressure applied by the pressure roll 64 to pressurize the sheet member P toward the heating roll 62 becomes the normal pressure.

[0064] (summary) As explained above, in the fixing device 34, the positioning member 82 and the oscillating member 78 are supported by the shaft member 80. In other words, the positioning member 82 and the oscillating member 78 are supported by the same member. This suppresses variations in the position of the oscillating member 78 between devices, compared to the case where the positioning member and the oscillating member are supported by different members. In other words, it suppresses variations in the pressure applied by the pressure roll 64 to press the sheet member P toward the heating roll 62 between devices.

[0065] Here, "similar components" refers to components that are integrally formed and cannot be divided without cutting or other means.

[0066] Furthermore, in the fixing device 34, the positioning member 82 and the oscillating member 78 are supported by a cylindrical shaft member 80 that extends in the depth direction. This suppresses variations in the position of the oscillating member 78 between devices, compared to the case where the positioning member and the oscillating member are mounted at different positions on a plate-shaped frame, respectively.

[0067] Furthermore, in the fixing device 34, the positioning member 82 is provided with a first positioning section 86 and a second positioning section 88 that contact the oscillating member 78 to determine its position. The oscillating member 78 is positioned at different positions. In other words, the oscillating member 78 is positioned at multiple positions. This allows the pressure applied by the pressure roll 64 to press the sheet member P toward the heating roll 62 to be changed to multiple values.

[0068] Furthermore, in the fixing device 34, the first positioning portion 86 and the second positioning portion 88 provided on the positioning member 82 are aligned in the axial direction (depth direction) of the shaft member 80. By moving the positioning member 82 axially along the shaft member 80, the oscillating member 78 comes into contact with the first contact portion 86a of the first positioning portion 86 or the second contact portion 88a of the second positioning portion 88. This allows the oscillating member 78 that contacts the first contact portion 86a to contact the second contact portion 88a with a simpler configuration compared to the case where the oscillating member that contacts the first contact portion comes into contact with the second contact portion by attaching and detaching the positioning member from the support member.

[0069] Furthermore, in the fixing device 34, the mounting portion 78b to which the lower end of the tension spring 74 is attached, and the contacted portion 78c to which the first contact portion 86a and the second contact portion 88a of the rocking member 78 make contact, are both on the same side with respect to the shaft member 80, as they are visible from the depth direction. This improves the degree of freedom of the shape of the rocking member 78 on the side of the shaft member 80 opposite to the mounting portion 78b and the contacted portion 78c of the tension spring 74, compared to the case where the mounting portion of the tension spring and the contacted portion are located on opposite sides with respect to the shaft member.

[0070] Furthermore, in the fixing device 34, when viewed from the depth direction, the distance from the axis of the shaft member 80 to the mounting portion 78b is defined as distance L1, and the contacted portion 78c is positioned on an arc R1 with the axis of the shaft member 80 as the center and distance L1 as the radius. As a result, deformation of the oscillating member 78 is suppressed compared to the case where the arc R1 and the contacted portion are separated, thereby suppressing variations in the position of the oscillating member 78 between devices.

[0071] Furthermore, the image forming apparatus 10 is equipped with a fixing device 34. This suppresses variations in the fixing quality of the toner image on the sheet member P between different apparatuses, compared to the case where the fixing device is equipped with a fixing device in which the oscillating member and the positioning member are supported by different members.

[0072] Although this disclosure has been described in detail with respect to specific embodiments, it will be apparent to those skilled in the art that this disclosure is not limited to such embodiments, and that various other embodiments are possible within the scope of this disclosure. For example, in the above embodiment, there were two positioning parts that contact the rocking member 78, a first positioning part 86 and a second positioning part 88, but there may be three or more, or there may be just one. However, if there is only one, the effect achieved by providing two will not be achieved.

[0073] Furthermore, although the pressurizing member in the above embodiment was a roll-shaped pressurizing roll 64, the pressurizing member may also be a member that includes a pressurizing belt.

[0074] Furthermore, in the above embodiment, the positioning member 82 and the oscillating member 78 were supported by the shaft member 80, but they may be supported at different positions on the plate-shaped frame member. However, in this case, the effect achieved by being supported by the shaft member will not be achieved.

[0075] Furthermore, in the above embodiment, the operator swung the swinging member 78 to the position shown by the dashed line in Figure 5, but a mechanism may be provided in which the swinging member swings in conjunction with the opening and closing of the maintenance door 11.

[0076] Furthermore, although there was only one positioning member 82 in the above embodiment, the pressure applied to press the sheet member P toward the heating roll 62 may be changed by providing multiple positioning members.

[0077] (((1))) A heating element that heats the image formed on the recording medium, A pressing member that sandwiches the recording medium between itself and the heating member and pressurizes the recording medium toward the heating member, A pressing member that presses the pressurizing member toward the heating member, An elastic member, one end of which is attached to the pressing member, elastically deforms to generate a pressing force that presses the recording medium against the heating member, The other end of the elastic member is attached to a swingable support member, which is supported by a support member so as to be swingable, and the amount of elastic deformation of the elastic member is determined by the position in which it is swingable, A positioning member that contacts the rocking member, determines the position of the rocking member, and is supported by the support member, A fixing device equipped with the following features.

[0078] (((2))) The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, The positioning member is attached to and supported by the shaft member. The fixing device described in (((1))).

[0079] (((3))) The positioning member is provided with multiple positioning parts that contact the rocking member to determine the position of the rocking member, and the rocking member is positioned at multiple positions. The fixing device described in (((1))) or (((2))).

[0080] (((4))) The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, The positioning units are provided in multiple locations at different positions aligned in the axial direction, The rocking member that contacts one of the positioning parts moves the positioning part along the shaft member in the axial direction, thereby separating from the first positioning part and contacting the other positioning part. The fixing device described in (((3))).

[0081] (((5))) The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, Viewed from the axial direction, the mounting portion on the rocking member to which the other end of the elastic member is attached and the contacted portion on the rocking member to which the positioning member contacts are on the same side with respect to the shaft member. A fixing device as described in any one of (((1))) to (((4))).

[0082] (((6))) The elastic force of the elastic member biases the oscillating member to contact the positioning member. When viewed from the axial direction, if the distance from the axis of the shaft member to the mounting portion is defined as the first distance, the contacted portion is arranged on an arc with the axis of the shaft member as the center and the radius being the first distance. The fixing device described in (((5))).

[0083] (((7))) A forming unit that forms an image on a recording medium, A fixing device according to any one of (((1))) to (((6))) for fixing the image formed on the recording medium by the forming unit onto the recording medium, An image forming apparatus equipped with the following features.

[0084] In the fixing device relating to (((1))), it is possible to suppress variations in the position of the oscillating member between devices, compared to the case where the positioning member and the oscillating member are supported by different members.

[0085] In the fixing device according to (((2))), the position of the oscillating member can be made less variable between devices compared to the case where the oscillating member and the positioning member are attached to different positions on a plate-shaped frame.

[0086] In the fixing device relating to (((3))), the pressure applied by the pressurizing member to pressurize the recording medium toward the heating member can be changed.

[0087] In the fixing device relating to (((4))), the positioning member can be attached to and detached from the support member, thereby allowing the oscillating member that contacts one positioning part to contact another positioning part with a simpler configuration compared to the case where the oscillating member that contacts one positioning part to contact another positioning part.

[0088] In the fixing device relating to (((5))), compared to the case where the mounting portion and the contacted portion of the elastic member are arranged on opposite sides with the shaft member in between, the degree of freedom of the shape of the oscillating member on the side opposite to the mounting portion and the contacted portion of the elastic member with the shaft member in between can be improved.

[0089] In the fixing device relating to (((6))), the variation in the position of the oscillating member between devices can be suppressed compared to the case where the arc with radius equal to the first distance, centered on the axis of the shaft member, and the contacted portion are separated when viewed from the axial direction.

[0090] In the image forming apparatus according to (((7))), it is possible to suppress variations in the image fixing quality on the recording medium between apparatuses, compared to the case in which the fixing apparatus is equipped in which the oscillating member and the positioning member are supported by different members. [Explanation of Symbols]

[0091] 10 Image forming apparatus 12 Image forming section (an example of an image forming section) 34 Fixing device 62. Heating Roll (Example of a heating component) 64. Pressure Roll (An example of a pressure component) 70 Pressing member 74. Tensile spring (an example of an elastic member) 78. Oscillating member 78b Mounting section 78c Contacted part 80. Axial member (an example of a support member) 82 Positioning member 86 First positioning unit 88 Second positioning unit P Sheet Material R1 arc

Claims

1. A heating element that heats the image formed on the recording medium, A pressing member that sandwiches the recording medium between itself and the heating member and pressurizes the recording medium toward the heating member, A pressing member that presses the pressurizing member toward the heating member, An elastic member, one end of which is attached to the pressing member, elastically deforms to generate a pressing force that presses the recording medium against the heating member, The other end of the elastic member is attached to a swingable support member, which is supported by a support member so as to be swingable, and the amount of elastic deformation of the elastic member is determined by the position in which it is swingable, A positioning member that contacts the rocking member, determines the position of the rocking member, and is supported by the support member, A fixing device equipped with the following features.

2. The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, The positioning member is attached to and supported by the shaft member. The fixing device according to claim 1.

3. The positioning member is provided with multiple positioning parts that contact the rocking member to determine the position of the rocking member, and the rocking member is positioned at multiple positions. The fixing device according to claim 1.

4. The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, The positioning units are provided in multiple locations at different positions aligned in the axial direction, The rocking member that contacts one of the positioning parts moves the positioning part along the shaft member in the axial direction, thereby separating from the first positioning part and contacting the other positioning part. The fixing device according to claim 3.

5. The support member supports the rocking member so that it can swing, and is a cylindrical shaft member extending in the axial direction of the rocking member, Viewed from the axial direction, the mounting portion on the rocking member to which the other end of the elastic member is attached and the contacted portion on the rocking member to which the positioning member contacts are on the same side with respect to the shaft member. The fixing device according to claim 1.

6. The elastic force of the elastic member biases the oscillating member to contact the positioning member. When viewed from the axial direction, if the distance from the axis of the shaft member to the mounting portion is defined as the first distance, the contacted portion is arranged on an arc with the axis of the shaft member as the center and the radius being the first distance. The fixing device according to claim 5.

7. A forming unit that forms an image on a recording medium, A fixing device according to any one of claims 1 to 6, for fixing an image formed on a recording medium by the forming unit onto the recording medium, An image forming apparatus equipped with the following features.

Images