Fixing apparatus and image forming apparatus

Abstract

This invention discloses a fixing apparatus and an image forming apparatus. The fixing apparatus includes: a heating member having a cylindrical part and a heating element, the cylindrical part being cylindrical and extending axially, rotating, and having grease coated on its inner circumferential surface; the heating element extending axially and contacting the inner circumferential surface to heat the cylindrical part; and a pressurizing member disposed on the opposite side of the heating element across the cylindrical part, forming a clamping portion between itself and the heating element to hold a recording medium, and pressurizing the recording medium toward the heating element. The heating element and the pressurizing member are configured such that, in the rotational direction of the cylindrical part, they are located on at least one side upstream or downstream of the clamping portion, and the inner circumferential surface and the components disposed inside the cylindrical part are in a non-contact state.

Description

Technical Field

[0001] This invention relates to a fixing device and an image forming device. Background Technology

[0002] The fixing apparatus described in Japanese Patent Application Publication No. 2015-166796 includes: a heating body, a fixing rotating body heated by the heating body, a guide member that guides the fixing rotating body and is built into the fixing rotating body, a lubricant between the fixing rotating body and the guide member, a pressure member that forms an engagement portion by pressing the fixing rotating body and the guide member together, and a drive unit that reverses the direction of the pressure member. The device is configured such that when the pressure member is rotated forward, a predetermined gap is formed between the fixing rotating body and the guide member, and when the pressure member is rotated in reverse, the gap is smaller than when it is rotated forward. Furthermore, the execution interval of the reverse drive depends on the number of sheets of recording material for which fixing processing has been performed. Summary of the Invention

[0003] The fixing unit of the image forming apparatus includes a heating member for heating a toner image formed on a recording medium and a pressurizing member for pressurizing the recording medium toward the heating member. The heating member has a rotating cylindrical member and a heating member for heating the cylindrical member by contact with the inner circumferential surface of the cylindrical member. Furthermore, a clamping portion for clamping the recording medium is formed between the heating member and the pressurizing member.

[0004] Here, the heating element is positioned on the opposite side of the pressure member, separated from the cylinder member, and the recording medium clamped by the engagement part is heated by the heating element via the cylinder member. On the other hand, grease is applied to the inner circumferential surface of the cylinder member to reduce the friction between the inner circumferential surface of the cylinder member and the heating element at the engagement part.

[0005] However, sometimes, in the rotational direction of the cylinder component, relative to the engagement portion on the upstream and downstream sides, the inner circumferential surface of the cylinder component contacts a component disposed inside the cylinder component. Because grease is trapped in the portion where the inner circumferential surface contacts the component, grease accumulates in this portion, resulting in less grease being supplied between the heating component and the cylinder component.

[0006] The objective of this invention is to reduce the frictional force generated between the inner circumferential surface of the cylinder member and the heating element, compared to the case where the inner circumferential surface of the cylinder member contacts the component disposed inside the cylinder member on the upstream and downstream sides relative to the engagement portion in the rotational direction of the cylinder member.

[0007] According to a first aspect of the present invention, a fixing apparatus is provided, comprising: a heating member having a cylindrical member and a heating element, the cylindrical member being cylindrical and extending axially, rotatable, and having grease coated on its inner circumferential surface; the heating element extending axially and contacting the inner circumferential surface to heat the cylindrical member; and a pressurizing member disposed on the opposite side of the heating element across the cylindrical member, forming an engagement portion between itself and the heating element to hold a recording medium, pressurizing the recording medium toward the heating element, the heating element and the pressurizing member being configured such that, in the rotational direction of the cylindrical member, they are located on at least one side upstream or downstream of the engagement portion, and the inner circumferential surface and a component disposed inside the cylindrical member are in a non-contact state.

[0008] According to a second aspect of the present invention, in the fixing apparatus involved in the first aspect, the mixing consistency of the grease is 250 or less.

[0009] According to a third aspect of the present invention, in the fixing apparatus involved in the first or second aspect, when the recording medium is held by the gripping portion, the inner circumferential surface and the components disposed inside the cylinder component are in a non-contact state in the rotation direction of the cylinder component relative to the gripping portion on the upstream side.

[0010] According to a fourth aspect of the present invention, in the fixing device involved in any of the first to third aspects, the inner circumferential surface and the component disposed inside the cylindrical component are in a non-contact state on both the upstream and downstream sides of the engagement portion relative to the rotation direction.

[0011] According to a fifth aspect of the present invention, in the fixing apparatus involved in any of the first to fourth aspects, with respect to the upstream edge of the cylindrical component in the direction of rotation of the heating element when the recording medium is held by the engagement portion, the central portion of the axial direction is recessed towards the downstream side of the rotation direction relative to the two ends of the axial direction.

[0012] According to a sixth aspect of the present invention, in the fixing device involved in the fifth aspect, the edge of the heating element is bent, so that the central portion in the axial direction is recessed towards the downstream side in the rotational direction relative to the two ends in the axial direction.

[0013] According to a seventh aspect of the present invention, an image forming apparatus is provided, comprising: a forming section that forms an image on a recording medium; and a fixing device according to any one of the first to sixth aspects, the fixing device fixing the image formed by the forming section on the recording medium onto the recording medium.

[0014] (Effect)

[0015] According to the first solution, compared to the case where the inner circumferential surface of the cylinder component contacts the component disposed inside the cylinder component on the upstream and downstream sides relative to the engagement portion in the rotation direction of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0016] According to the second solution, even when a grease with a mixture consistency of 250 or less is applied to the inner circumferential surface of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heat-generating component can be reduced compared to the case where the inner circumferential surface of the cylinder component contacts the component disposed inside the cylinder component on the upstream and downstream sides relative to the engagement portion in the rotation direction of the cylinder component.

[0017] According to the third embodiment, compared to the case where the inner circumferential surface of the cylinder component and the component disposed inside the cylinder component are in a non-contact state only on the downstream side relative to the engagement portion in the rotation direction of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0018] According to the fourth embodiment, compared to the case where the inner circumferential surface of the cylinder component and the component disposed inside the cylinder component are in a non-contact state only on one side of the engagement portion in the rotation direction of the cylinder component (either upstream or downstream), the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0019] According to the fifth scheme, compared with the case where the edge of the heating element extends axially, the amount of grease that comes into contact with the edge of the heating element and flows to the outer side of the axial direction can be reduced.

[0020] According to the sixth solution, compared to the case where the edge of the heating element extends axially, it is possible to suppress the accumulation of grease in the central part of the heating element along the axial direction.

[0021] According to the seventh solution, compared with the case where the fixing device is provided, uneven fixing of the image can be suppressed: the fixing device is in contact with the inner circumferential surface of the cylinder component and the component disposed inside the cylinder component on the upstream and downstream sides relative to the engagement part in the rotation direction of the cylinder component. Attached Figure Description

[0022] Figure 1 This is a schematic structural diagram illustrating an image forming apparatus according to an embodiment of the present invention;

[0023] Figure 2 This is a schematic structural diagram showing the image forming unit included in the image forming apparatus according to an embodiment of the present invention;

[0024] Figure 3 This is a structural diagram showing the overall structure of the fixing device according to an embodiment of the present invention;

[0025] Figure 4 This is a top view showing the heater and other components included in the fixing apparatus according to an embodiment of the present invention;

[0026] Figure 5 This is an enlarged view showing the engagement portion of the fixing device according to an embodiment of the present invention;

[0027] Figure 6 This is a structural diagram showing the overall structure of the fixing device relative to the comparison method of the embodiment of the present invention. Detailed Implementation

[0028] according to Figures 1 to 6 An example of a fixing apparatus and an image forming apparatus according to an embodiment of the present invention will be described. Furthermore, arrow H in each figure represents the vertical direction, indicating the up-down direction of the apparatus. Arrow W is orthogonal to arrow H and is horizontal, representing the width direction of the apparatus. Arrow D is orthogonal to both arrow H and arrow W and is horizontal, representing the depth direction of the apparatus.

[0029] (Overall structure of the image forming apparatus)

[0030] like Figure 1 As shown, the image forming apparatus 10 includes a housing 10a that houses all the constituent components. Inside the housing 10a are a housing section 12 for housing a sheet-like recording medium P and an image forming section 14 for forming an image on the recording medium P. Furthermore, inside the housing 10a is a transport section 16 for transporting the recording medium P from the housing section 12 to the image forming section 14.

[0031] [Image forming unit 14]

[0032] like Figure 1 As shown, the image forming unit 14 has image forming units 22Y, 22M, 22C, and 22K (hereinafter referred to as "22Y to 22K") that form toner images of yellow (Y), magenta (M), cyan (C), and black (K). In the following description, the Y, M, C, and K at the end of the symbols are omitted unless otherwise specified.

[0033] Furthermore, the image forming unit 14 includes an intermediate transfer belt 24 for transferring toner images formed by the image forming units 22 of each color. The image forming unit 14 also includes a primary transfer roller 26 for transferring toner images formed by the image forming units 22 of each color onto the intermediate transfer belt 24. Additionally, the image forming unit 14 includes a secondary transfer roller 28 for transferring the toner images transferred from the primary transfer roller 26 to the intermediate transfer belt 24 onto the recording medium P.

[0034] Image forming units 22 of various colors are arranged on the upper side of the intermediate transfer belt 24, along the width direction. For example... Figure 2 As shown, each image forming unit 22 has an image holder 32 that rotates in the direction of the arrow in the figure.

[0035] Around the image holder 32, starting upstream in the rotational direction of the image holder 32, a charging device 23, an exposure device 36, a developing device 38, and a removal device 40 are sequentially arranged. The charging device 23 charges the image holder 32, and the exposure device 36 exposes the charged image holder 32, forming an electrostatic latent image on the image holder 32. Then, the developing device 38 develops the electrostatic latent image formed on the image holder 32 to form a toner image. Additionally, the removal device 40 removes toner that has come into contact with the image holder 32 and remains on it. Furthermore, as... Figure 1 As shown, each color exposure device 36 has a color toner storage section 39 above it, which stores the toner supplied to the developing device 38.

[0036] The intermediate transfer belt 24 is formed in a triangular shape with its apex facing downwards. Winding rollers 41, 42, 43, 44, and 45 are provided on the inner circumference of the intermediate transfer belt 24 for winding it. As an example, the intermediate transfer belt 24 is driven to rotate by the winding roller 43, contacting the image holder 32 while moving in one direction (e.g., ...). Figure 1 It moves (rotates) in a counter-clockwise direction in a cyclical manner.

[0037] Each of the primary transfer rollers 26 of different colors is disposed on the opposite side of the image holder 32, separated by the intermediate transfer belt 24. Moreover, the primary transfer rollers 26 and the image holder 32 are positioned as the first transfer position for the toner image formed on the image holder 32 to be transferred to the intermediate transfer belt 24.

[0038] The secondary transfer roller 28 is positioned on the opposite side of the winding roller 42, separated by the intermediate transfer belt 24. Furthermore, the area between the secondary transfer roller 28 and the winding roller 42 is designated as a second transfer position for transferring the toner image transferred on the intermediate transfer belt 24 to the recording medium P.

[0039] The transport section 16 has a delivery roller 46 that feeds the recording medium P stored in the storage section 12 onto the transport path 48. Furthermore, the transport section 16 has a plurality of transport rollers 50 that transport the recording medium P along the transport path 48 toward the second transfer position.

[0040] Furthermore, the transport unit 16 includes a transport roller 52 that transports the recording medium P, on which the toner image has been transferred at the second transfer position, along the transport path 48. The transport unit 16 also includes an ejection roller 54 that discharges the transported recording medium P from the housing 10a. Additionally, a fixing device 60 is disposed between the transport roller 52 and the ejection roller 54 along the transport path 48. The fixing device 60 will be described in detail later.

[0041] (The function of an image forming apparatus)

[0042] Next, the operation of the image forming apparatus 10 will be explained. Specifically, the image forming operation that forms an image on the recording medium P will be explained.

[0043] exist Figure 1 In the image forming apparatus 10 shown, the recording medium P delivered from the receiving section 12 by the delivery roller 46 is fed into the second transfer position by a plurality of transport rollers 50.

[0044] On the other hand, in the image forming units 22 of each color, by Figure 2 The image holder 32, charged by the charging device 23, is exposed by the exposure device 36, forming an electrostatic latent image on the image holder 32. The electrostatic latent image is developed by the developing device 38, forming a toner image on the image holder 32.

[0045] The toner images of various colors formed by the image forming units 22 are superimposed on the intermediate transfer belt 24 at the first transfer position by the primary transfer rollers 26 of each color to form a color image. Then, the images formed on the... Figure 1 The color image on the intermediate transfer belt 24 shown is transferred to the recording medium P conveyed by the transport roller 50 via the secondary transfer roller 28.

[0046] The recording medium P, on which the toner image has been transferred, is conveyed to the fixing unit 60 via the conveyor roller 52, where the transferred toner image is fixed. The recording medium P, on which the toner image has been fixed, is discharged from the frame 10a via the discharge roller 54.

[0047] (Main structural components)

[0048] Next, the fixing device 60 of this embodiment will be described. Figure 3 As shown, the fixing apparatus 60 includes a heating element 62 for heating the recording medium P and a pressurizing element 82 for pressurizing the recording medium P toward the heating element 62. Specifically, the heating element 62 and the pressurizing element 82 are opposite each other in the vertical direction, and the heating element 62 is disposed above the pressurizing element 82.

[0049] [Heating component 62]

[0050] like Figure 3As shown, the heating element 62 includes a cylindrical fixing belt 64 and a heater 68 disposed inside the fixing belt 64. The heater 68 heats up by being subjected to voltage, thereby heating the fixing belt 64. Additionally, the heating element 62 has a support pad 70 supporting the heater 68 and a support frame 74 supporting the support pad 70. The fixing belt 64 is an example of a cylindrical component. The heater 68 is an example of a heating element.

[0051] -Fixing belt 64, heater 68-

[0052] like Figure 3 As shown, the fixing belt 64 is cylindrical and extends in the depth direction, rotating counterclockwise while its inner circumferential surface 64a is in contact with the heater 68. The depth direction is an example of axial direction.

[0053] Furthermore, grease G is coated on the inner circumferential surface 64a of the fixing belt 64. In this embodiment, as an example, the mixing consistency of the grease G specified in JIS K 2220 is 250 or less. That is, the grease G coated on the inner circumferential surface 64a of the fixing belt 64 is harder than grease G with a mixing consistency greater than 250. In addition, the viscosity of the grease G at 200°C, as measured by a rheometer, is 50 to 1500 Pa·s, preferably 80 to 1000 Pa·s, more preferably 100 to 500 Pa·s. The weight loss rate of the grease G after being heated and stored at 230°C for 336 hours is 0 to 20 wt%, preferably 0 to 15 wt%, more preferably 0 to 10 wt%.

[0054] Grease G has a structure in which a thickener is incorporated into a base oil. The base oil of grease G is silicone oil, preferably dimethyl silicone oil, methylphenyl silicone oil, or diphenyl silicone oil, and may also contain a portion of side chains. The weight-average molecular weight (Mw) of the silicone oil is 10,000 to 100,000, preferably 10,000 to 60,000, and more preferably 15,000 to 40,000.

[0055] Furthermore, in grease G, the thickener component is selected from one or more inorganic materials such as melamine cyanurate, boron nitride, carbon black, silica, graphite, molybdenum disulfide, zinc stearate, and tungsten disulfide. The average particle size (D50v) of the thickener is 0.01 to 15 μm, preferably 0.1 to 10 μm, and more preferably 0.1 to 5 μm. The weight ratio of base oil in the composition of grease G is 40 to 95 wt%, preferably 50 to 85 wt%, and more preferably 50 to 75 wt%.

[0056] The viscosity of grease G was determined using the following method. The grease sample was clamped between parallel plates with a diameter of 40 mm. The viscosity was measured using a dynamic viscoelasticity measuring device (ARES-G2 rheometer, manufactured by TA Instruments) with a gap of 1 mm, an angular velocity of 0.1 rad / s, and a temperature increase of 6 °C / min from 40 °C to 200 °C.

[0057] A 5g sample of lubricating grease was collected and placed in an aluminum cup. The sample was then heated in an oven at 230℃ for 336 hours. The weight reduction rate of lubricating grease G was calculated based on the weight before and after heating.

[0058] The average particle size of the thickener was determined using the following method: A 2g sample of grease was placed on filter paper, and 30g of THF (tetrahydrofuran) was added. The mixture was then filtered by suction to separate the base oil and the thickener. The separated thickener was dispersed in water, and the particle size distribution was determined using a particle size distribution measuring device (LS13320, Beckman Coulter).

[0059] The heater 68 is a so-called planar heater, which, when viewed from the depth direction, is a rectangle extending in the width direction along the conveying path 48 and also extends in the depth direction. Furthermore, the heater 68 contacts the inner peripheral surface 64a of the fixing belt 64 via the contact surface 68b. Additionally, in the heater 68, the upstream edge 68a of the fixing belt 64 in the rotation direction opens into the interior space of the fixing belt 64. Furthermore, as... Figure 4 As shown, the upstream edge 68a is bent in a manner that the central portion in the depth direction is recessed towards the downstream side in the rotation direction of the fixing belt 64 compared to the two ends in the depth direction.

[0060] The portion of the fixing belt 64 that contacts the heater 68 is straight when viewed from the depth direction and runs along the transport path 48. Moreover, the heater 68 heats the fixing belt 64 by applying voltage to the entire area in contact with it.

[0061] -Support pad 70, support frame 74-

[0062] The support pad 70 is formed of resin material, such as Figure 3 As shown, the support pad 70 is positioned on the opposite side of the portion of the fixing belt 64 that contacts the heater 68, across the heater 68. Furthermore, the length of the support pad 70 in the width direction is the same as the length of the heater 68 in the width direction, and the support pad 70 overlaps the heater 68. Moreover, the support pad 70 supports the heater 68 throughout the depth direction.

[0063] The support frame 74 is formed by bending a metal plate and has a U-shaped cross-section with the support pad 70 side open when viewed from the depth direction. Furthermore, the support frame 74 supports the support pad 70 by clamping the support pad 70 into its two end portions from the width direction. This support frame 74 extends in the depth direction, supporting the support pad 70 throughout the depth direction. Moreover, the two end portions of the support frame 74 in the depth direction protrude from the fixing belt 64, and the protruding portions are supported by frame members (not shown).

[0064] [Pressure component 82]

[0065] The pressure component 82 is roller-shaped, such as... Figure 3 As shown, it is positioned on the opposite side of the heating element 62 across the transport path 48. Additionally, the pressurizing element 82 and the heater 68 clamp the fixing belt 64.

[0066] In this structure, the pressurizing component 82 is driven by a motor (not shown) and rotates in the direction of the arrow (clockwise). Furthermore, the fixing belt 64 rotates in the direction of the arrow (counterclockwise) as the pressurizing component 82 rotates.

[0067] Here, the pressure-applying member 82 forms an engagement portion N between itself and the heating member 62 to hold the recording medium P, and uses this engagement portion N to apply pressure to the recording medium P toward the heating member 62. Furthermore, the heating member 62 and the pressure-applying member 82 are arranged such that, in the rotation direction of the fixing belt 64 (hereinafter referred to as the "belt rotation direction"), the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N on the upstream and downstream sides.

[0068] Here, as described above, the engagement portion N is the part of the recording medium P where the pressure applying member 82 applies pressure towards the heating member 62. Therefore, the range of this engagement portion N can be determined by placing a surface pressure measuring plate between the heating member 62 and the pressure applying member 82. The engagement portion N is the range of pressure generated by the measurement of the surface pressure measuring plate.

[0069] Furthermore, the length of the meshing portion N in the rotational direction is set to L1. Thus, as... Figure 5 As shown, in the belt rotation direction, the upstream side relative to the engagement portion refers to the range E1 extending from the upstream end P1 of the engagement portion N in the belt rotation direction to the upstream side of the belt rotation direction up to the length L1. Furthermore, in the belt rotation direction, the downstream side relative to the engagement portion refers to the range E2 extending from the downstream end P2 of the engagement portion N in the belt rotation direction to the downstream side of the belt rotation direction up to the length L1.

[0070] (The function of the main structural components)

[0071] Next, the operation of the fixing device 60 will be explained together with the fixing device 160 of the comparison method. First, regarding the structure of the fixing device 160 of the comparison method, the parts that are different from the fixing device 60 of this embodiment will be explained.

[0072] [Structure of fixing device 160]

[0073] like Figure 6 As shown, the fixing device 160 includes a heating element 162 and a pressurizing element 82. The heating element 162 includes a cylindrical fixing belt 64, a heater 168, a support pad 170, and a support frame 74.

[0074] The heater 168, viewed from the depth direction, is a rectangle extending along its width direction and further into the depth direction. Moreover, the heater 168 contacts the inner peripheral surface 64a of the fixing belt 64 via a contact surface 168b. In the heater 168, the upstream edge 168a in the rotational direction extends into the depth direction. Furthermore, the length of the heater 168 in the width direction is greater than that of the heater 68 (see reference). Figure 3 The length in the width direction is long.

[0075] A pair of clamping portions 170a are provided on the support pad 170 to clamp the heater 168 in the width direction. Moreover, in the clamping portion 170a, the lower end of the fixing belt 64 side is disposed on the same surface as the contact surface 168b of the heater 168.

[0076] Furthermore, in the belt rotation direction, on both the upstream and downstream sides of the engagement portion N, the inner circumferential surface 64a of the fixing belt 64 contacts the heater 168 and the support pad 170. Specifically, on the upstream side of the engagement portion N, the inner circumferential surface 64a contacts the end of one side (left side in the figure) of the heater 168 in the width direction and the lower end of a clamping portion 170a. In other words, on the upstream side of the engagement portion N in the belt rotation direction, a stagnant portion (B1 in the figure) is formed where grease G is trapped between the fixing belt 64 and the engagement portion N, thus accumulating grease G.

[0077] Furthermore, on the downstream side relative to the engagement portion N, the inner circumferential surface 64a contacts the end of the heater 168 on the other side in the width direction (right side in the figure) and the lower end of the other clamping portion 170a. In other words, on the downstream side relative to the engagement portion N in the belt rotation direction, a stagnant portion (B2 in the figure) is formed where grease G is trapped between the fixing belt 64 and the grease G, thus accumulating grease G.

[0078] [Function of fixing devices 60 and 160]

[0079] Before the fixing units 60 and 160 are operated, the voltage applied to the heaters 68 and 168 is stopped. Furthermore, the rotation of the pressure-applying component 82 stops.

[0080] When fixing the toner image transferred to the recording medium P, a motor (not shown) transmits driving force to the pressure unit 82, such as... Figure 3 , Figure 5 As shown, the pressurizing component 82 rotates in the direction of the arrow in the figure.

[0081] As a result, the fixing belt 64 rotates in the direction of the arrow in the figure, driven by the pressure member 82. Additionally, the grease G applied to the inner circumferential surface 64a of the fixing belt 64 also moves along with the inner circumferential surface 64a as the fixing belt 64 rotates. Furthermore, a voltage is applied to the heaters 68 and 168 by a power source not shown in the figure. As a result, the heaters 68 and 168 generate heat, thereby heating the rotating fixing belt 64.

[0082] Here, in the fixing device 160 of the comparison method, such as Figure 6 As shown, a stagnant portion B1 for accumulating grease G is formed on the upstream side relative to the engagement portion N in the belt rotation direction. Due to the formation of the stagnant portion B1, the amount of grease G supplied between the heater 168 and the fixing belt 64 will be reduced.

[0083] Furthermore, in the fixing device 160, a stagnant portion B2 for accumulating grease G is formed downstream of the engagement portion N in the belt rotation direction. Because of the stagnant portion B2, the amount of grease G moving with the inner circumferential surface 64a decreases as the fixing belt 64 rotates. Consequently, the amount of grease G supplied between the heater 168 and the fixing belt 64 decreases.

[0084] On the other hand, in the fixing device 60 of this embodiment, such as Figure 3 As shown, a heating member 62 and a pressure member 82 are arranged such that the inner circumferential surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the occlusal portion N on the upstream and downstream sides.

[0085] Therefore, the formation of stagnant portions where grease G would accumulate on the upstream and downstream sides relative to the engagement portion N is suppressed. As a result, the amount of grease G supplied between the heater 68 and the fixing belt 64 is increased compared to the fixing device 160 of the comparative method.

[0086] (Summarize)

[0087] As described above, in the fixing device 60, the heating member 62 and the pressurizing member 82 are arranged such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N on the upstream and downstream sides. Therefore, compared to the fixing device 160 of the comparative embodiment, the amount of grease G supplied between the fixing belt 64 and the heater 68 is increased. In other words, compared to the case where the inner peripheral surface 64a of the fixing belt 64 and the components disposed inside the fixing belt 64 are in contact relative to the engagement portion N on the upstream and downstream sides in the belt rotation direction, the frictional force (dynamic friction) generated between the inner peripheral surface 64a of the fixing belt 64 and the heater 68 is reduced.

[0088] Furthermore, in the fixing apparatus 60, a grease G with a mixing consistency of 250 or less is applied to the inner peripheral surface 64a of the fixing belt 64. That is, a grease G that is harder than a grease G with a mixing consistency greater than 250 is applied to the inner peripheral surface 64a of the fixing belt 64. When such a hard grease G is applied to the inner peripheral surface 64a, if stagnant portions B1 and B2 are formed as in the fixing apparatus 160 of the comparative embodiment, grease G tends to accumulate in the stagnant portions B1 and B2.

[0089] However, in the fixing apparatus 60 of this embodiment, the stagnant portions B1 and B2 are not formed. Therefore, even when a grease with a mixing consistency of 250 or less is applied, the frictional force generated between the inner peripheral surface 64a of the fixing belt 64 and the heater 68 is reduced compared to the case where the inner peripheral surface 64a of the fixing belt 64 contacts the components disposed inside the fixing belt 64 on the upstream and downstream sides relative to the engagement portion N in the belt rotation direction.

[0090] Additionally, in the fixing device 60, such as Figure 4 As shown, regarding the edge 68a of the heater 68, the central portion in the depth direction is recessed towards the downstream side in the rotation direction compared to the two ends in the depth direction. Therefore, compared to the case where the edge of the heater extends in the depth direction, the grease G that moves with the rotation of the fixing belt 64 can be prevented from contacting the edge of the heater 68 and flowing outward in the depth direction.

[0091] Furthermore, the edge 68a of the heater 68 is curved such that its central portion in the depth direction is recessed relative to both ends in the depth direction towards the downstream side of the fixing belt 64 in the belt rotation direction. As a result, compared to the case where the edge of the heater extends along the depth direction, the accumulation of grease G in the central portion of the heater 68 in the depth direction can be suppressed.

[0092] Furthermore, in the image forming apparatus 10, compared with the case of the fixing apparatus 160 with a comparison mode, the friction force generated between the inner peripheral surface 64a and the heater 68 is reduced, thus suppressing the generation of uneven fixing of the toner image.

[0093] Furthermore, although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to these embodiments, and it will be apparent to those skilled in the art that the present invention can be implemented in various other ways within the scope of the present invention. For example, in the above embodiment, the heating member 62 and the pressure member 82 are configured such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N on both the upstream and downstream sides. However, the heating member 62 and the pressure member 82 may also be configured such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to at least one side of the engagement portion N on both the upstream and downstream sides in the belt rotation direction. Thus, compared to the case where the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in contact relative to both sides of the engagement portion N on both the upstream and downstream sides in the belt rotation direction, the frictional force generated between the inner peripheral surface 64a of the fixing belt 64 and the heater 68 can be reduced.

[0094] Furthermore, in the above embodiment, the heating member 62 and the pressurizing member 82 are configured such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N on both the upstream and downstream sides. However, the heating member 62 and the pressurizing member 82 may also be configured such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N only on the upstream side in the belt rotation direction. As a result, compared to the case where the non-contact state is only on the downstream side relative to the engagement portion N, the amount of grease G supplied between the heater 68 and the fixing belt 64 increases, and the frictional force generated between the inner peripheral surface 64a of the fixing belt 64 and the heater 68 decreases.

[0095] Furthermore, in the above embodiment, the heating member 62 and the pressurizing member 82 are arranged such that the inner peripheral surface 64a and the components disposed inside the fixing belt 64 are in a non-contact state relative to the engagement portion N on both the upstream and downstream sides. Therefore, compared to the case where the inner peripheral surface and the components disposed inside the fixing belt are in a non-contact state relative to the engagement portion N only on one side (upstream or downstream) in the belt rotation direction, the amount of grease G supplied between the heater 68 and the fixing belt 64 increases, and the frictional force generated between the inner peripheral surface 64a of the fixing belt 64 and the heater 68 decreases.

[0096] Furthermore, in the above embodiment, regarding the edge 68a of the heater 68, the central portion in the depth direction is recessed towards the downstream side in the rotational direction compared to both ends in the depth direction, but the edge of the heater may also extend in the depth direction. However, in this case, the effect of arranging the edge in such a way that the central portion in the depth direction is recessed towards the downstream side in the rotational direction compared to both ends in the depth direction is not effective.

[0097] In addition, in the above embodiment, the mixing consistency of grease G is 250 or less, but, for example, the mixing consistency of grease G may be 250 or less and 200 or more.

[0098] (Postscript) (((1)))

[0100] A fixing device, comprising:

[0101] A heating element comprising a cylindrical component and a heating element, the cylindrical component being cylindrical and extending axially, rotatable, and having grease coated on its inner circumferential surface; the heating element extending axially and contacting the inner circumferential surface to heat the cylindrical component; and

[0102] A pressurizing component, disposed on the opposite side of the heating component across the cylindrical component, forms an engaging portion between itself and the heating component to hold the recording medium, thereby pressurizing the recording medium toward the heating component.

[0103] The heating component and the pressurizing component are configured such that, in the rotational direction of the cylindrical component, they are positioned relative to at least one side of the engagement portion, on the upstream and downstream sides, and the inner circumferential surface and the component disposed inside the cylindrical component are in a non-contact state. (((2)))

[0105] According to the fixing device described in ((1)), wherein,

[0106] The consistency of the grease mixture is below 250. (((3)))

[0108] According to the fixing device described in ((1)) or ((2)), wherein,

[0109] When the recording medium is held by the engagement portion, the inner circumferential surface and the components disposed inside the cylinder are in a non-contact state on the upstream side of the cylinder relative to the engagement portion in the direction of rotation of the cylinder component. (((4)))

[0111] The fixing device according to any one of ((1))) to ((3))) wherein,

[0112] In the direction of rotation, the inner circumferential surface and the component disposed inside the cylindrical component are in a non-contact state relative to the engagement portion on the upstream and downstream sides. (((5)))

[0114] The fixing device according to any one of ((1))) to ((4))) wherein,

[0115] With respect to the upstream edge of the cylindrical component in the direction of rotation when the recording medium is held by the engagement portion, the central portion of the axial direction is recessed towards the downstream side of the rotation direction compared to the two ends of the axial direction. (((6)))

[0117] According to the fixing device described in ((5)), wherein,

[0118] The edge of the heating element is bent, so that the central portion in the axial direction is recessed downstream of the two ends in the axial direction. (((7)))

[0120] An image forming apparatus, comprising:

[0121] Forming section, the forming section forming an image on a recording medium; and

[0122] The fixing apparatus described in any one of ((1))) to ((6))) fixes an image formed by the forming portion on the recording medium onto the recording medium.

[0123] (Effect)

[0124] In the fixing device described in (((1))), compared to the case where the inner circumferential surface of the cylinder component contacts the component disposed inside the cylinder component on the upstream and downstream sides relative to the engagement part in the rotation direction of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0125] In the fixing device described in (((2))), even when a grease with a mixture consistency of 250 or less is applied to the inner circumferential surface of the barrel component, the frictional force generated between the inner circumferential surface of the barrel component and the heating component can be reduced compared to the case where the inner circumferential surface of the barrel component contacts the component disposed inside the barrel component on the upstream and downstream sides relative to the engagement part in the rotation direction of the barrel component.

[0126] In the fixing device involved in ((3)), compared with the case where the inner circumferential surface of the cylinder component and the component disposed inside the cylinder component are in a non-contact state only on the downstream side relative to the engagement part in the rotation direction of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0127] In the fixing device involved in ((4)), compared with the case where the inner circumferential surface of the cylinder component and the component disposed inside the cylinder component are in a non-contact state only on one side of the upstream or downstream side relative to the engagement part in the rotation direction of the cylinder component, the frictional force generated between the inner circumferential surface of the cylinder component and the heating component can be reduced.

[0128] In the fixing device involved in ((5)), compared with the case where the edge of the heating element extends axially, the amount of grease that comes into contact with the edge of the heating element and flows to the outer side of the axial direction can be reduced.

[0129] In the fixing device involved in ((6)), compared with the case where the edge of the heating element extends along the axial direction, it is possible to suppress the accumulation of grease in the central part of the heating element along the axial direction.

[0130] In the image forming apparatus described in ((7)), compared to the case where a fixing device is provided, uneven fixing of the image can be suppressed: the fixing device is in contact with the inner circumferential surface of the cylinder member and the component disposed inside the cylinder member on the upstream and downstream sides of the engagement portion in the rotation direction of the cylinder member.

Claims

1. A fixing device characterized by comprising: have: A heating component, comprising a cylindrical component and a heating element, wherein the cylindrical component is cylindrical and extends axially, is rotatable, and has grease coated on its inner circumferential surface; the heating element extends axially and contacts the inner circumferential surface to heat the cylindrical component. as well as A pressurizing component, disposed on the opposite side of the heating component across the cylindrical component, forms an engaging portion between itself and the heating component to hold the recording medium, thereby pressurizing the recording medium toward the heating component. The heating component and the pressurizing component are configured such that, in the rotational direction of the cylindrical component, they are positioned relative to at least one side of the engagement portion, on the upstream and downstream sides, and the inner circumferential surface and the component disposed inside the cylindrical component are in a non-contact state.

2. The fixing device according to claim 1, wherein, The consistency of the grease mixture is below 250.

3. The fixing device according to claim 1 or 2, wherein, When the recording medium is held by the engagement portion, the inner circumferential surface and the components disposed inside the cylinder are in a non-contact state on the upstream side of the cylinder relative to the engagement portion in the direction of rotation of the cylinder component.

4. The fixing device according to any one of claims 1 to 3, wherein, In the direction of rotation, the inner circumferential surface and the component disposed inside the cylindrical component are in a non-contact state relative to the engagement portion on the upstream and downstream sides.

5. The fixing device according to any one of claims 1 to 4, wherein, With respect to the upstream edge of the cylindrical component in the direction of rotation when the recording medium is held by the engagement portion, the central portion of the axial direction is recessed towards the downstream side of the rotation direction compared to the two ends of the axial direction.

6. The fixing device according to claim 5, wherein, The edge of the heating element is bent, so that the central portion in the axial direction is recessed downstream of the two ends in the axial direction.

7. An image forming apparatus characterized by comprising: have: Forming section, the forming section forming an image on a recording medium; and The fixing apparatus according to any one of claims 1 to 6, wherein the fixing apparatus fixes an image formed by the forming portion on the recording medium onto the recording medium.

Images