Heating device and image processing device

Abstract

A heating device and an image processing device capable of suppressing excessive temperature increase of a heat generating component are disclosed. The heating device of an embodiment has a belt and a heat generating component. The belt is in a cylindrical shape. The heat generating component is provided on an inner side of the belt. The heat generating component is formed in a circular arc shape along an inner peripheral surface of the belt. The heat generating component is in contact with the inner peripheral surface of the belt in a manner capable of sliding with respect to the inner peripheral surface of the belt. When a deflection amount of the belt is set as D, a radius of curvature of the inner peripheral surface of the belt is set as A, and a radius of curvature of an outer peripheral surface of the heat generating component is set as B, D ≥ 10 mm and 0.4 mm ≥ A - B ≥ 0 mm are satisfied.

Description

Technical Field

[0001] Embodiments of the present invention relate to a heating device and an image processing device. Background Technology

[0002] The image processing apparatus includes a heating device that uses the heat of a belt to fix toner (recording agent) onto a sheet. The heating device heats the belt via electromagnetic induction. To compensate for insufficient heat generation from the belt, the heating device includes a heating element that contacts the inner circumferential surface of the belt. The heating element is formed in an arc shape along the inner circumferential surface of the belt. Due to dimensional deviations in the heating element, insufficient contact between the belt and the heating element, inadequate heat transfer between the heating element and the belt, and the possibility of overheating of the heating element are all possible. Summary of the Invention

[0003] The problem to be solved by the present invention is to provide a heating device and an image processing device that can suppress excessive heating of the heating component.

[0004] The heating device of the embodiment has a belt and a heating element. The belt is cylindrical. The heating element is disposed on the inner side of the belt. The heating element is formed as an arc along the inner circumferential surface of the belt. The heating element contacts the inner circumferential surface of the belt in a manner that allows it to slide relative to the inner circumferential surface of the belt. When the deflection of the belt is set as D, the radius of curvature of the inner circumferential surface of the belt is set as A, and the radius of curvature of the outer circumferential surface of the heating element is set as B, the following equations (1) and (2) are satisfied:

[0005] D≥10mm…(1)

[0006] 0.4mm≥AB≥0mm…(2). Attached Figure Description

[0007] Figure 1 This is a schematic diagram of an image processing apparatus according to an embodiment.

[0008] Figure 2 This is a schematic diagram of the heating device according to the embodiment.

[0009] Figure 3 This is a schematic diagram of the heating element in the embodiment.

[0010] Figure 4 This is a diagram showing the relationship between the width of the heating element and the gap between the strip and the heating element in the embodiment.

[0011] Figure 5 This is a graph showing the relationship between the gap between the belt and the heating element in the embodiment and the temperature of the thermostat.

[0012] Figure 6This is a diagram showing the relationship between the difference between the inner diameter of the belt and the outer diameter of the heating element in the embodiment and the tightness of the belt and the heating element.

[0013] Figure 7 This is a graph showing the relationship between the width of the heating element in the embodiment and the temperature of the thermostat.

[0014] Figure 8 This is an explanatory diagram of the method for measuring the deflection of the belt in the embodiment.

[0015] Figure 9 This is a graph showing the measurement results of the deflection of a belt with an inner diameter of 30 mm in the embodiment.

[0016] Figure 10 This is a graph showing the measurement results of the deflection of a belt with an inner diameter of 40 mm in the embodiment.

[0017] Symbol Explanation

[0018] 1…Image processing device, 24…Heating device, 30…Belt, 40…Heating element, 46…Thermostat, A…Radius of curvature of the inner circumferential surface of the belt, B…Radius of curvature of the outer circumferential surface of the heating element, D…Deflection of the belt, H…Height dimension of the heating element, W…Width dimension of the heating element. Detailed Implementation

[0019] Hereinafter, the heating device and image processing device of the embodiment will be described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the image processing apparatus 1 according to the first embodiment.

[0021] For example, image processing apparatus 1 is a multi-function peripheral (MFP). Image processing apparatus 1 reads an image formed on a sheet-like recording medium (hereinafter referred to as "sheet") such as paper to generate digital data (image file). Based on the digital data, image processing apparatus 1 forms an image on the sheet using toner.

[0022] The image processing apparatus 1 includes a display unit 2, an image reading unit 3, a sheet feeding unit 4, an image forming unit 5, a sheet flipping unit 6, and a control unit 7.

[0023] Display unit 2 functions as an output interface, displaying text and images. It also functions as an input interface, receiving instructions from the user. For example, display unit 2 is a touch panel type liquid crystal display.

[0024] For example, the image reading unit 3 is a color scanner. Color scanners include CIS (Contact Image Sensor), CCD (Charge Coupled Device), etc. The image reading unit 3 uses the sensor to read the image formed on the sheet and generates digital data.

[0025] The sheet supply unit 4 supplies sheet material for image output to the image forming unit 5. The sheet supply unit 4 includes a paper tray 10 and a pickup roller 11. The paper tray 10 stores the sheet material P. The pickup roller 11 removes the sheet material P from the paper tray 10.

[0026] The image forming unit 5 forms an image on the sheet using a toner. The image forming unit 5 forms the image based on image data read by the image reading unit 3 or image data received from an external device. For example, the image formed on the sheet is an output image referred to as a hard copy, printout, etc.

[0027] The image forming unit 5 includes an intermediate transfer body 20, an imaging unit 21, a primary transfer roller 22, a secondary transfer unit 23, and a heating device 24.

[0028] The transfer process in the image forming unit 5 includes a first transfer process and a second transfer process. In the first transfer process, the primary transfer roller 22 transfers the image (toner image) formed by toner on the photosensitive drum of each imaging unit 21 onto the intermediate transfer body 20. In the second transfer process, the secondary transfer unit 23 transfers the image onto the sheet using toner of various colors layered on the intermediate transfer body 20.

[0029] The intermediate transfer body 20 is a ring-shaped band. The intermediate transfer body 20 extends along... Figure 1 The arrow rotates in the U direction. An image with toner is formed on the surface of the intermediate transfer body 20.

[0030] The imaging unit 21 uses various colors (e.g., five colors) of toner to form an image. Multiple imaging units 21 are provided along the intermediate transfer body 20.

[0031] The primary transfer roller 22 transfers the toner image formed by the imaging unit 21 onto the intermediate transfer body 20.

[0032] The secondary transfer unit 23 includes a secondary transfer roller 25 and a secondary transfer opposing roller 26. The secondary transfer unit 23 transfers the toner image formed on the intermediate transfer body 20 onto the sheet.

[0033] The heating device 24 fixes the toner image transferred onto the sheet by heating and pressurizing. The sheet with the image formed by the heating device 24 is discharged from the paper discharge section 8 to the outside of the device.

[0034] The sheet flipping section 6 is disposed on the side of the heating device 24. The sheet flipping section 6 flips the back surface of the sheet. For example, the back surface flipping of the sheet is performed when images are formed on both the front and back surfaces of the sheet.

[0035] The control unit 7 controls each component of the image processing device 1.

[0036] Next, the heating device 24 will be described.

[0037] Figure 2 This is a schematic diagram of the heating device 24 in the embodiment.

[0038] like Figure 2 As shown, the heating device 24 includes a belt 30, an internal belt mechanism 31, a pressure roller 32, and an induced current generating unit 33.

[0039] The strip 30 is a cylindrical annular strip. For example, the inner diameter of the strip 30 is set to be between 35 mm and 50 mm. For example, the strip 30 is formed by sequentially stacking a heating layer (conductive layer) and a release layer, which serve as the heating element, on a base layer. For example, the base layer is formed of polyimide resin (PI). For example, the heating layer is formed of a non-magnetic metal such as copper (Cu). For example, the release layer is formed of a fluoropolymer such as tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA). It should be noted that the layer structure is not limited as long as the strip 30 has a heating layer.

[0040] The internal mechanism 31 is disposed inside the belt 30. The internal mechanism 31 includes a heating element 40, a frame 44, a gap pad 45, a thermostat 46, a bracket 47, a first force-applying element 48, and a second force-applying element 49.

[0041] The heating element 40 is in contact with the inner circumferential surface of the strip 30. The heating element 40, sandwiching the strip 30, is positioned opposite the induced current generating part 33. The heating element 40 is formed of a magnetic material. For example, the heating element 40 is formed of a solid magnetic alloy with a Curie point lower than that of the heating layer. For example, the heating element 40 is formed of a thin-walled metal part made of a solid magnetic alloy such as an iron or nickel alloy with a Curie point of 220°C to 230°C.

[0042] It should be noted that the heating element 40 can also be formed from a thin-walled metal component with magnetic properties, such as iron, nickel, or stainless steel. The heating element 40 can also be formed from resin containing magnetic powder, provided it possesses magnetic properties. The heating element 40 can also be formed from a magnetic material (ferrite).

[0043] The heating element 40 has a long side along the axial direction (hereinafter referred to as the "belt axis") of the belt 30. The heating element 40 is bent along the inner circumferential surface of the belt 30. The heating element 40 is in slidable contact with the inner circumferential surface of the belt 30. The heating element 40 includes a bent portion 50, a first bent portion 51, and a second bent portion 52. The bent portion 50, the first bent portion 51, and the second bent portion 52 are integrally formed from the same component.

[0044] The curved portion 50 is formed as an arc along the inner circumferential surface of the belt 30. The curved portion 50 is in contact with the inner circumferential surface of the belt 30. The radius of curvature of the curved portion 50 is smaller than the radius of curvature of the belt 30.

[0045] Alternatively, chromium nitride and diamond-like carbon (DLC) plating or coating can be applied to the outer peripheral surface of the bent portion 50. By applying chromium nitride and DLC plating or coating, the sliding properties between the bent portion 50 and the belt 30 are improved.

[0046] The first bend 51 bends inward from the first end 55 of the bend 50 in the circumferential direction. Multiple first bends 51 are provided along the belt axis. Each first bend 51 has an annular portion 57. The annular portion 57 is supported by a swing axis (not shown) along the belt axis. The heating element 40 is capable of swinging about the swing axis.

[0047] The second bend 52 bends inward from the second end 56 of the bend 50 in the circumferential direction. Multiple second bends 52 are provided axially along the belt. The second bends 52 are connected to the first end of the first force-applying member 48. For example, the first force-applying member 48 is an elastic member such as a compression spring. The second end of the first force-applying member 48 is connected to a support bar 59. The support bar 59 is fixed to the frame 44. The heating member 40 is pressed against the belt 30 by the first force-applying member 48.

[0048] The gap pad 45 presses the belt 30 against the pressure roller 32. The gap pad 45 is fixed to the frame 44. The gap pad 45 creates a gap 65 between the belt 30 and the pressure roller 32. The gap pad 45 has a gap forming surface 66 that forms the gap 65. The gap forming surface 66 bends toward the inside of the belt 30 when viewed from the belt axial direction. The gap forming surface 66 bends along the outer circumferential surface of the pressure roller 32 when viewed from the belt axial direction.

[0049] For example, the spacer 45 is formed of elastic materials such as silicone rubber and fluororubber. The spacer 45 can also be formed of heat-resistant resins such as polyimide resin (PI), polyphenylene sulfide resin (PPS), polyethersulfone resin (PES), liquid crystal polymer (LCP), and phenolic resin (PF).

[0050] For example, a sheet-like friction-reducing component (not shown) is disposed between the belt 30 and the gap pad 45. For example, the friction-reducing component is formed of a sheet component with good sliding properties and excellent wear resistance, as well as a release layer. The friction-reducing component is fixedly supported on the belt internal mechanism 31. The friction-reducing component slides in contact with the inner circumferential surface of the traveling belt 30. The friction-reducing component may also be formed of a sheet component with lubricity. For example, the sheet component may also be made of glass fiber sheet impregnated with fluororesin. For example, the friction-reducing component may also contain a lubricating oil such as silicone oil.

[0051] The thermostat 46 functions as a safety device for the heating device 24. The thermostat 46 detects the temperature of the heating element 40. The thermostat 46 operates when the heating element 40 overheats abnormally and its temperature rises to a cutoff threshold. Through the operation of the thermostat 46, the current to the induced current generating unit 33 is cut off. By cutting off the current to the induced current generating unit 33, abnormal overheating of the heating device 24 is prevented.

[0052] The thermostat 46 is connected to the first end of the second force-applying component 49. For example, the second force-applying component 49 is an elastic component such as a compression spring. The second end of the second force-applying component 49 is connected to the bracket 47. The bracket 47 is fixed to the frame 44. The thermostat 46 is pressed against the heating component 40 by the second force-applying component 49. The thermostat 46 follows the swing of the heating component 40 by the pressing of the second force-applying component 49. By following the swing of the heating component 40, the thermostat 46 is always in contact with the heating component 40.

[0053] The pressure roller 32 applies pressure to the belt 30 via a pressure mechanism (not shown). For example, the pressure roller 32 may have a heat-resistant silicone sponge and a silicone rubber layer surrounding a metal core. For example, a release layer may be disposed on the surface of the pressure roller 32. The release layer is formed of a fluoropolymer resin such as PFA resin.

[0054] The belt 30 and the pressure roller 32 are driven by a drive unit (not shown) such as a motor. The pressure roller 32 rotates in the direction of arrow Q driven by the motor. When the belt 30 comes into contact with the pressure roller 32, the belt 30 rotates in the direction of arrow R driven by the pressure roller 32. When the belt 30 separates from the pressure roller 32, the belt 30 rotates in the direction of arrow R driven by the motor.

[0055] A virtual straight line passing through the rotation center of belt 30 and the rotation center of pressure roller 32 when viewed from the belt axis is designated as the first straight line J. A virtual straight line orthogonal to the first straight line J and passing through the rotation center of belt 30 when viewed from the belt axis is designated as the second straight line K. When viewed from the belt axis, the heating element 40 is positioned closer to the induced current generating part 33 than the second straight line K.

[0056] An induced current generating unit 33 is disposed outside the belt 30. The induced current generating unit 33 faces the belt 30. The induced current generating unit 33 faces the heating element 40 across the belt 30. The induced current generating unit 33 includes a coil (not shown). A high-frequency current is applied to the coil by an inverter drive circuit (not shown). By allowing the high-frequency current to flow through the coil, a high-frequency magnetic field is generated around the coil. The magnetic flux of the high-frequency magnetic field heats the belt 30.

[0057] A magnetic flux is generated between the heating element 40 and the strip 30 by a magnetic flux produced by a coil. This magnetic flux heats the strip 30. The heating element 40 changes from strongly magnetic to paramagnetic when it exceeds the Curie point. If the heating element 40 exceeds the Curie point, a magnetic circuit is not formed through the heating element 40 and the heating layer, and it no longer assists in heating the strip 30. By forming the heating element 40 from a solid magnetic alloy, it is possible to assist in heating the strip 30 at low temperatures, with the Curie point as the boundary, and to suppress excessive heating of the strip 30 at high temperatures.

[0058] Next, the heating element 40 will be described.

[0059] Figure 3 This is a schematic diagram of the heating element 40 in the embodiment. Figure 3 The bending portions 51, 52, etc. of the heating element 40 are omitted from the illustration. Figure 3 As shown, the heating element 40 has a curved portion 50 that is arc-shaped when viewed from the belt axis. When viewed from the belt axis, when the curved portion 50 is semi-circular, the arc center C of the curved portion 50 is located on the same surface including both ends (first end 55 and second end 56) of the curved portion 50 in the circumferential direction.

[0060] The maximum width of the two ends of the circumferential direction of the curved portion 50 of the heating element 40 when viewed from the axial direction is defined as the width dimension W of the heating element. The maximum height of the curved portion 50 of the heating element 40, which is orthogonal to the width dimension W of the heating element when viewed from the axial direction, is defined as the height dimension H of the heating element.

[0061] A virtual straight line, taken from the arc center C of the bend 50 when viewed axially, and passing through the two circumferential ends (first end 55 and second end 56) of the bend 50, is designated as the third straight line L. For example... Figure 2 As shown, when viewed from the belt axis, the third straight line L is arranged parallel to the second straight line K. When viewed from the belt axis, the third straight line L is positioned closer to the induced current generating section 33 than the second straight line K. When viewed from the belt axis, the arc center C of the curved section 50 is positioned on the first straight line J.

[0062] As described above, the magnetic flux generated by the coil of the induced current generating unit 33 heats the heating layer of the belt 30, forming a magnetic circuit between the heating element 40 and the heating layer, thereby causing the heating element 40 to self-heat. If there is heat transfer between the heating element 40 and the belt 30, the temperature of the heating element 40 is maintained at a temperature approximately 20°C higher than the temperature of the belt 30. The thermostat 46 is disposed in the area where the paper passes through along the belt axis; therefore, if the fixing temperature is set to 160°C, the detection temperature of the thermostat 46 is approximately 180°C.

[0063] However, if the seal between the belt and the heating element is insufficient, and heat transfer between the heating element and the belt is inadequate, the heating element may overheat. If the heating element overheats, the temperature detected by the thermostat will also rise excessively. That is, even if the belt temperature is not abnormal, the thermostat will still activate, resulting in what is known as premature thermostat cutoff.

[0064] Therefore, it is important to ensure a sufficient seal between the belt and the heating element in order to suppress excessive heating of the heating element. Here, the gap between the belt and the heating element is defined as an indicator of the seal. The inventors of this application conducted in-depth research and found that the gap between the belt and the heating element is related to the width of the heating element.

[0065] Figure 4 This is a diagram showing the relationship between the width of the heating element and the gap between the strip and the heating element in the embodiment. Figure 4 In the diagram, the horizontal axis represents the width of the heating element [mm], and the vertical axis represents the gap between the belt and the heating element [mm]. For example... Figure 4 As shown, the following relationship can be observed: as the width of the heating element increases, the gap between the strip and the heating element decreases.

[0066] Furthermore, when the heating element is formed as an arc along the inner circumferential surface of the strip, it is ideal to measure the profile of the heating element in terms of managing its dimensions. However, measuring the profile is extremely difficult in managing the dimensions of the heating element during mass production.

[0067] Therefore, in this application, by measuring the width dimension of the heating element, mass production management of the heating element's dimensions can be achieved. For example, when the heating element is formed by stamping, the blank size (product size) corresponding to the stamping die size is stable. Therefore, the dimensions of the arc-shaped heating element can be managed for mass production by measuring the width dimension of the heating element. Figure 3 The width dimension W of the heating element shown.

[0068] The inventors of this application conducted in-depth research and found that the temperature of the thermostat is related to the width of the heating element.

[0069] Figure 5 This is a graph showing the relationship between the gap between the belt and the heating element in the embodiment and the temperature of the thermostat. Figure 5 In the diagram, the horizontal axis represents the temperature of the thermostat [°C], and the vertical axis represents the gap between the belt and the heating element [mm]. For example... Figure 5 As shown, the following tendency can be observed: if the gap between the belt and the heating element increases, the temperature of the thermostat increases. As mentioned above, the following relationship exists: as the width of the heating element increases, the gap between the belt and the heating element decreases (refer to...). Figure 4 In other words, it can be said that there is a tendency for the thermostat to become hotter if the width of the heating element becomes smaller.

[0070] Furthermore, the inner diameter of the belt is related to its rigidity. A quantity that quantifies belt rigidity is the belt's deflection. Low belt rigidity means the belt is easily deformed by external forces. For example, when a heating element is pressed from the inside of the belt, the belt's shape is easily deformed by external forces causing the belt to rotate, inertial forces, and the reaction force from sliding on the inner surface. That is, the belt cannot maintain a neat, rounded shape, nor can it mimic the rounded shape of the heating element. As a result, the belt's shape is unstable during rotation, thus reducing the seal between the belt and the heating element and impairing heat transfer between them.

[0071] Figure 6 This diagram illustrates the relationship between the difference between the inner diameter of the belt and the outer diameter of the heating element in the embodiment, and the tightness of the fit between the belt and the heating element. Here, the inner diameter of the belt refers to the diameter of the inner side of the belt when it is set into a perfect cylindrical shape. The outer diameter of the heating element refers to the maximum width (width dimension of the heating element) of the two ends of the curved portion in the circumferential direction when the curved portion of the heating element is set into a semi-circular arc shape.

[0072] The evaluation of the seal between the heating element and the thermostat is set as follows: Even if there are dimensional deviations in the heating element, the thermostat temperature will remain below the target value. Figure 7 The case where the target value T is shown (corresponding to the mass production location) is set to "0". The case where the thermostat temperature exceeds the target value due to the deviation of the heating element size (the case where the thermostat temperature is lower than the target value if the width of the heating element is managed) is set to "△". Although not shown, the case where the thermostat temperature exceeds the target value regardless of the deviation of the heating element size is set to "×". For example, when a heating element with an outer diameter of 39.2mm is set for a belt with an inner diameter of 40mm, the fit is basically "×", but if the width of the heating element is managed, the fit is "△".

[0073] like Figure 6As shown, it can be recognized that when the difference between the inner diameter of the belt and the outer diameter of the heating element is 0.6 mm or 0.7 mm, the seal between the belt and the heating element is evaluated as 0. On the other hand, when the difference between the inner diameter of the belt and the outer diameter of the heating element is 0.8 mm, the seal between the belt and the heating element is evaluated as △.

[0074] Figure 7 This is a graph showing the relationship between the width of the heating element in the embodiment and the temperature of the thermostat. Figure 7 In the diagram, the horizontal axis represents the width of the heating element [mm], and the vertical axis represents the temperature of the thermostat [°C]. Figure 7 In the diagram, symbol G1 represents the relationship when a heating element with an outer diameter of 39.6 mm is set on a belt with an inner diameter of 40 mm, symbol G2 represents the relationship when a heating element with an outer diameter of 39.2 mm is set on a belt with an inner diameter of 40 mm, and symbol T represents the target temperature value of the thermostat.

[0075] like Figure 7 As shown, it can be recognized that in either pattern G1 or pattern G2, if the width of the heating element increases, the temperature of the thermostat decreases. It can also be recognized that by increasing the outer diameter of the heating element while maintaining the same inner diameter of the belt, the temperature of the thermostat decreases.

[0076] exist Figure 7 In the diagram, pattern G1 corresponds to a 0.4mm difference between the inner diameter of the belt and the outer diameter of the heating element, while pattern G2 corresponds to a 0.8mm difference. In the case of pattern G1, the thermostat temperature is approximately 20°C lower than in the case of pattern G2, and even with dimensional deviations in the heating element, the thermostat temperature remains below the target value T. On the other hand, in the case of pattern G2, depending on dimensional deviations in the heating element, the thermostat temperature may exceed the target value T, but if the width of the heating element is controlled, the thermostat temperature will remain below the target value T. In other words, if the difference between the inner diameter of the belt and the outer diameter of the heating element is less than 0.7mm, the seal between the belt and the heating element is good (refer to...). Figure 6 The temperature of the thermostat is difficult to depend on the width of the heating element (see reference). Figure 7 ).

[0077] The belt 30 and the heating element 40 in the embodiment satisfy the following formulas (1) and (2).

[0078] D≥10mm…(1)

[0079] 0.4mm≥AB≥0mm…(2)

[0080] Here, D represents the belt deflection, A represents the radius of curvature of the inner circumferential surface of the belt, and B represents the radius of curvature of the outer circumferential surface of the heating element. Specifically, the belt deflection D refers to the displacement of the axial end of a belt with a length of 100 mm relative to its axial direction when a 200 g weight is placed on the upper center of the belt. The radius of curvature A of the inner circumferential surface of the belt is equivalent to half the inner diameter of the belt. The radius of curvature B of the outer circumferential surface of the heating element is equivalent to half the outer diameter of the heating element.

[0081] It should be noted that a deflection D of 10 mm or more corresponds to an inner diameter of 35 mm or more. A difference (AB) of 0.4 mm between the inner circumference radius A of the belt and the outer circumference radius B of the heating element corresponds to a difference of 0.8 mm between the inner diameter of the belt and the outer diameter of the heating element. Figure 7 The figure shown is G2.

[0082] When changing the dimensions of the heating element 40, it is preferable to maintain the inscribed relationship with respect to the inner circumferential surface of the belt 30. Within the range that at least satisfies the above-described equation (2), when viewed from the belt axial direction, the arc center C of the curved portion 50 of the heating element 40 is preferably positioned on the first straight line J. That is, as the difference (AB) between the radius of curvature A of the inner circumferential surface of the belt and the radius of curvature B of the outer circumferential surface of the heating element approaches 0 mm, the arc center C of the curved portion 50 is positioned on the first straight line J. Figure 2 The paper is offset to the right and close to the center (rotation center) of the belt 30. When viewed from the belt axis, the arc center C of the curved portion 50 of the heating element 40 is arranged on the first straight line J, thereby maintaining the positional relationship with respect to the induced current generating portion 33, thus making it easy to obtain the required heat.

[0083] Preferably, the belt 30 and the heating element 40 in the embodiment further satisfy the following formula (3).

[0084] 0.35mm≥AB…(3)

[0085] It should be noted that the difference (AB) between the radius of curvature A of the inner circumference of the belt and the radius of curvature B of the outer circumference of the heating element is 0.35 mm, which is equivalent to the difference between the inner diameter of the belt and the outer diameter of the heating element being 0.7 mm (refer to...). Figure 6 ).

[0086] Alternatively, the belt 30 and the heating element 40 in the embodiment may further satisfy the following equations (4) and (5) instead of further satisfying the above equation (3).

[0087] 0.4mm≥AB>0.35mm…(4)

[0088] W>H…(5)

[0089] Here, W represents the width of the heating element, and H represents the height of the heating element (see reference). Figure 3 ).

[0090] It should be noted that B in equation (4) above is set as the theoretical value of the blank size of the metal sheet (the size of the stamping die). When the width W of the heating element is larger than the height H of the heating element, it is equivalent to... Figure 3 The shape shown is a semi-circular arc.

[0091] As explained above, the heating device 24 of the embodiment includes a belt 30 and a heating element 40. The belt 30 is cylindrical. The heating element 40 is disposed inside the belt 30. The heating element 40 is formed as an arc along the inner circumferential surface of the belt 30. The heating element 40 contacts the inner circumferential surface of the belt 30 in a slidable manner. When the deflection of the belt 30 is set to D, the radius of curvature of the inner circumferential surface of the belt 30 is set to A, and the radius of curvature of the outer circumferential surface of the heating element 40 is set to B, the following equations (1) and (2) are satisfied.

[0092] D≥10mm…(1)

[0093] 0.4mm≥AB≥0mm…(2)

[0094] The above structure achieves the following effects.

[0095] Even if there are dimensional deviations in the heating element 40, the belt 30 can still be fully sealed to the heating element 40, ensuring sufficient heat transfer between them. Therefore, excessive heating of the heating element 40 can be suppressed.

[0096] Preferably, the heating device 24 further satisfies the following equation (3).

[0097] 0.35mm≥AB…(3)

[0098] The above structure achieves the following effects.

[0099] This allows for a closer fit between the belt 30 and the heating element 40, enabling more efficient heat transfer between them. Consequently, it can more effectively suppress excessive heating of the heating element 40.

[0100] Alternatively, the heating device 24 may further satisfy the following equations (4) and (5) instead of further satisfying the above equation (3).

[0101] 0.4mm≥AB>0.35mm…(4)

[0102] W>H…(5)

[0103] The above structure achieves the following effects.

[0104] By managing the width dimension W of the heating element, even if there are dimensional deviations in the heating element 40, the belt 30 and the heating element 40 can be fully sealed together, ensuring sufficient heat transfer between them. Therefore, excessive heating of the heating element 40 can be suppressed.

[0105] The heating device 24 further includes a thermostat 46, which contacts the inner circumferential surface of the heating element 40 and detects the temperature of the heating element 40, thereby achieving the following effect.

[0106] By suppressing excessive heating of the heating element 40, premature shut-off of the thermostat 46 can be prevented. Therefore, as a safety device for the heating device 24, the operation of the thermostat 46 can be made stable.

[0107] The image processing apparatus 1, by incorporating the aforementioned heating device 24, achieves the following effects.

[0108] The heating device 24 can suppress excessive heating of the heat-generating component 40. Therefore, the image processing device 1 can improve image quality.

[0109] Next, variations of the implementation method will be described.

[0110] The heating device of the embodiment satisfies the following equations (1) and (2).

[0111] D≥10mm…(1)

[0112] 0.4mm≥AB≥0mm…(2)

[0113] Alternatively, the heating device can satisfy the following equation (6) instead of the above equation (2).

[0114] 0.98≤B / A≤1…(6)

[0115] Here, B / A represents the ratio of the radius of curvature B of the outer peripheral surface of the heating element to the radius of curvature A of the inner peripheral surface of the belt.

[0116] The curved portion of the heating element in this embodiment has a semi-circular arc shape when viewed from the belt axis. Alternatively, the curved portion of the heating element may have an arc shape with a circumferential length smaller than that of a semi-circular arc when viewed from the belt axis. Or, the curved portion of the heating element may have an arc shape with a circumferential length larger than that of a semi-circular arc when viewed from the belt axis. For example, the curved portion of the heating element can simply be formed as an arc shape along the inner circumferential surface of the belt.

[0117] The image processing apparatus described in this embodiment is an image forming apparatus. In contrast, the image processing apparatus can also be a desaturation apparatus. When the image processing apparatus is a desaturation apparatus, the heating device performs a process of desaturating (removing) the image formed on the sheet using a desaturating toner.

[0118] According to at least one embodiment described above, when the deflection of the belt is set to D, the radius of curvature of the inner circumferential surface of the belt is set to A, and the radius of curvature of the outer circumferential surface of the heating element is set to B, the following equations (1) and (2) are satisfied.

[0119] D≥10mm…(1)

[0120] 0.4mm≥AB≥0mm…(2)

[0121] The above structure achieves the following effects.

[0122] Even with dimensional deviations in the heating element, the belt and the heating element can still be fully sealed, ensuring sufficient heat transfer between them. Therefore, excessive heating of the heating element can be suppressed.

[0123] While several embodiments have been described, these embodiments are merely illustrative and not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, and likewise within the scope of the invention as described in the claims and its equivalents.

[0124] Example

[0125] The present invention will be described in more detail below through embodiments, but the present invention is not limited to the following embodiments.

[0126] [Example]

[0127] The embodiment uses a cylindrical belt. The axial length of the belt is 100 mm. Both belts with an inner diameter of 30 mm and 40 mm are used.

[0128] [Experimental Example]

[0129] The deflection of belts with an inner diameter of 30 mm and 40 mm was measured for both in this embodiment. A height gauge manufactured by Mitutoyo was used to measure the deflection. Six samples were taken for each inner diameter. The deflection was measured at both ends of the belt along its axial direction (respectively...). Figure 8 The strip shown is located at the upper left end (Le) and the upper right end (Re) of the paper.

[0130] Figure 8 This is an explanatory diagram of the method for measuring the deflection of the belt in the embodiment.

[0131] The method for measuring belt deflection sets the initial position of the belt (position before deflection) to 0. Here, the initial position of the belt is relative to the position of the belt before a 200g weight is placed on the upper center of the belt along its axial direction; it refers to the degree to which the belt does not move (not towards the center). Figure 8 The degree of rotation in the direction of the arrow is relative to the light load position when the measuring part of the height gauge is mounted on the upper part of the axial end of the belt.

[0132] The belt deflection was measured after a 200g weight was placed on the upper center of the belt relative to its axial direction. The belt deflection was measured relative to the position after the 200g weight was placed on the upper center of the belt relative to its axial direction, to the degree that the belt did not move (not towards the belt). Figure 8 The degree of rotation in the direction of the arrow is relative to the light load position when the measuring part of the height gauge is mounted on the upper part of the axial end of the belt.

[0133] Figure 9 This is a graph showing the measurement results of the deflection of a belt with an inner diameter of 30 mm in the embodiment.

[0134] like Figure 9 As shown, the average deflection of a belt with an inner diameter of 30 mm can be confirmed to be 6.2 mm.

[0135] Figure 10 This is a graph showing the measurement results of the deflection of a belt with an inner diameter of 40 mm in the embodiment.

[0136] like Figure 10 As shown, the average deflection of the belt with an inner diameter of 40 mm can be confirmed to be 14.4 mm.

[0137] As can be seen from the above, if the inner diameter of the belt increases, the belt deflection increases (the belt rigidity decreases). It should be noted that the midpoint between the deflection of a belt with an inner diameter of 30mm and that of a belt with an inner diameter of 40mm is approximately 10mm. Therefore, it can be inferred that when the belt deflection is greater than 10mm, it is equivalent to the case where the inner diameter of the belt is greater than 35mm.

Claims

1. A heating device, characterized in that, have: A tubular belt; and The heating element is disposed on the inner side of the belt, formed in an arc shape along the inner circumferential surface of the belt, and contacts the inner circumferential surface of the belt in a manner that allows it to slide relative to the inner circumferential surface of the belt. When a 200g weight is placed on the upper center of a belt with a length of 100mm relative to the belt axis, the displacement of the belt axial end is defined as the belt deflection D; half the diameter of the inner side of the belt when the belt is cylindrical is defined as the radius of curvature A of the inner circumference of the belt; and the radius of curvature B of the outer circumference of the heating element is defined as B. The following equations (1) and (2) are satisfied: D≥10mm…(1) 0.4mm≥AB≥0mm…(2).

2. The heating device according to claim 1, characterized in that, The heating device further satisfies the following equation (3): 0.35mm≥AB…(3).

3. The heating device according to claim 1, characterized in that, When the width dimension of the heating element is set to W and the height dimension of the heating element is set to H, the heating device further satisfies the following equations (4) and (5): 0.4mm≥AB>0.35mm…(4) W>H…(5) 4. The heating device according to any one of claims 1 to 3, characterized in that, The heating device further includes a thermostat, which contacts the inner circumferential surface of the heating element and detects the temperature of the heating element.

5. An image processing apparatus, characterized in that, The image processing apparatus includes the heating device according to any one of claims 1 to 4.

Images