Fixing device and image forming device

Abstract

The present invention provides a fixing device and an image forming apparatus that suppress deformation of a fixing member caused by uneven lubricant temperature, compared to a case where the rotation of the fixing member is controlled without considering the lubricant's temperature. The fixing device of the present invention includes: a fixing member formed in an annular shape and rotatably arranged, having an outer peripheral surface that contacts a recording material and used to fix an image on the recording material to the recording material; a contact member configured to contact the inner peripheral surface of the fixing member and extending along the axis of the annular fixing member; a temperature detection unit that detects the temperature of the lubricant adhering to the inner peripheral surface of the fixing member; and a processor that controls the rotation of the fixing member based on the temperature detected by the temperature detection unit.

Description

Technical Field

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

[0002] Patent Document 1 discloses a process of changing the temperature distribution of a heater in the longitudinal direction so as to optimize the amount of camber of a pressure roller.

[0003] Patent Document 2 discloses a fixing device including: an endless belt member; a fixing member fixedly arranged in contact with the inner circumferential surface of the belt member; a support roller in contact with the belt member and rotatably supporting the belt member; and a heating component for heating the belt member.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-156570

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2014-174503 Summary of the Invention

[0008] [Problems to be solved by the invention]

[0009] In an apparatus for fixing an image on a recording medium to the recording medium, a fixing member is provided that is formed in an annular shape and is rotatably arranged. In addition, in order to improve sliding between a member that contacts the fixing member and the fixing member, a lubricant is sometimes applied to the fixing member.

[0010] If the lubricant temperature varies, the fixing member will move more easily in areas where the lubricant temperature is high, while it will move less easily in areas where the lubricant temperature is low. This can easily cause deformation of the fixing member, which can degrade the quality of the image fixed to the recording material or damage the fixing member.

[0011] An object of the present invention is to suppress deformation of a fixing member due to temperature variations of a lubricant, compared to a case where the rotation of the fixing member is controlled without considering the temperature of the lubricant.

[0012] [Technical means to solve the problem]

[0013] The invention described in Technical Solution 1 is a fixing device, which includes: a fixing member formed in an annular shape and rotatably arranged, having an outer peripheral surface in contact with a recording material, and being used to fix an image on the recording material to the recording material; a contact member configured to contact the inner peripheral surface of the fixing member and extend in the axial direction of the annular fixing member; a temperature detection part that detects the temperature of a lubricant attached to the inner peripheral surface of the fixing member; and a processor that controls the rotation of the fixing member based on the temperature detected by the temperature detection part.

[0014] The invention described in claim 2 is the fixing device according to claim 1 , wherein the temperature detection portion detects the temperature of the lubricant by detecting the temperature of a member in contact with the lubricant.

[0015] The invention described in claim 3 is the fixing device according to claim 2 , wherein the contact member is a heating member that heats the fixing member, and the temperature detection portion detects the temperature of the lubricant by detecting the temperature of the heating member.

[0016] The invention described in Technical Solution 4 is a fixing device according to Technical Solution 1, wherein the temperature detection parts are provided in plurality and are configured to have different positions in the axial direction, and when the difference between the temperature detected by one of the temperature detection parts and the temperature detected by the other temperature detection parts is less than a predetermined threshold value, the processor starts rotating the fixing component or increases the rotation speed of the fixing component.

[0017] The invention described in Technical Solution 5 is a fixing device according to Technical Solution 4, wherein, when the lower temperature between the temperature detected by the one temperature detection unit and the temperature detected by the other temperature detection unit is greater than a predetermined threshold value, the processor starts rotating the fixing component or increases the rotation speed of the fixing component.

[0018] The invention described in Technical Solution 6 is a fixing device according to Technical Solution 4, wherein, when the difference between the temperature detected by the temperature detection portion arranged at the end portion of the fixing member in the axial direction and the temperature detected by the temperature detection portion arranged at the central portion of the fixing member in the axial direction is less than a predetermined threshold value, the processor starts rotating the fixing member or increases the rotation speed of the fixing member.

[0019] The invention described in claim 7 is the fixing device according to claim 4 , wherein the predetermined threshold value can be changed.

[0020] The invention described in claim 8 is the fixing device according to claim 7 , wherein the processor changes the threshold value based on information related to the usage time of the fixing device.

[0021] The invention described in claim 9 is the fixing device according to claim 8 , wherein, when the value determined based on the information related to the usage time of the fixing device exceeds a predetermined value, the processor reduces the threshold value compared to a case where it does not exceed the predetermined value.

[0022] The invention described in Technical Solution 10 is a fixing device according to Technical Solution 1, wherein when the temperature of the lubricant located at the end of the fixing member in the axial direction is greater than a predetermined threshold, the processor starts rotating the fixing member or increases the rotation speed of the fixing member.

[0023] The invention described in claim 11 is the fixing device according to claim 1 , wherein the processor further adjusts the temperature of the lubricant.

[0024] The invention described in Technical Solution 12 is a fixing device according to Technical Solution 11, wherein the temperature detection parts are provided in plurality and are configured to have different positions in the axial direction, and the processor adjusts the temperature of the lubricant so that the difference between the temperature detected by one of the temperature detection parts and the temperature detected by the other temperature detection parts is less than a predetermined threshold value.

[0025] The invention described in Technical Solution 13 is an image forming device, which includes: an image forming component that forms an image on a recording material; a fixing component that is formed in an annular shape and is rotatably arranged, has an outer peripheral surface that contacts the recording material on which the image is formed by the image forming component, and is used to fix the image on the recording material to the recording material; a contact member that is configured to contact the inner peripheral surface of the fixing component and extend in the axial direction of the annular fixing component; a temperature detection part that detects the temperature of the lubricant attached to the inner peripheral surface of the fixing component; and a processor that controls the rotation of the fixing component based on the temperature detected by the temperature detection part.

[0026] The invention described in Technical Solution 14 is a fixing device, comprising: a fixing component formed in an annular shape and rotatably arranged, having an outer peripheral surface in contact with a recording material, and used for fixing an image on the recording material to the recording material; a contact component configured to contact the inner peripheral surface of the fixing component and extend along the axial direction of the annular fixing component; a temperature detection component for detecting the temperature of the lubricant attached to the inner peripheral surface of the fixing component; and a processing component for controlling the rotation of the fixing component based on the temperature detected by the temperature detection component.

[0027] [Effects of the Invention]

[0028] According to the invention of claim 1 , deformation of the fixing member due to temperature variations of the lubricant can be suppressed compared to a case where the rotation of the fixing member is controlled without considering the temperature of the lubricant.

[0029] According to the invention of claim 2, the temperature of the lubricant can be detected more simply than when the temperature of the lubricant is directly detected.

[0030] According to the invention of claim 3 , the temperature of the lubricant can be detected more simply than when the temperature of the lubricant is directly detected.

[0031] According to the invention of technical solution 4, deformation of the fixing member can be suppressed compared to the case where the rotation of the fixing member is started or the rotation speed of the fixing member is increased even though the difference between the temperature detected by one temperature detection unit and the temperature detected by other temperature detection units is greater than a predetermined threshold value.

[0032] According to the invention of claim 5 , the fixing member can be rotated more smoothly than when the fixing member is started to rotate or the rotation speed of the fixing member is increased even when the temperature is relatively low and lower than the threshold value.

[0033] According to the invention of claim 6 , when the temperature difference between the lubricant at the ends and the center of the fixing member in the axial direction is small, the rotation of the fixing member can be started or the rotation speed of the fixing member can be increased.

[0034] According to the invention of claim 7 , deformation of the fixing member can be further suppressed compared to a configuration in which the threshold value cannot be changed.

[0035] According to the invention of claim 8 , deformation of the fixing member that may easily occur depending on the usage time of the fixing device can be suppressed compared to a case where the threshold value is not changed based on information related to the usage time of the fixing device.

[0036] According to the invention of claim 9 , deformation of the fixing member can be further suppressed compared to a configuration in which the threshold value is not reduced when the value determined based on the information related to the usage time of the fixing device exceeds a predetermined value.

[0037] According to the invention of claim 10 , deformation of the fixing member can be suppressed compared to a case where the rotation of the fixing member is started or the rotation speed of the fixing member is increased even when the temperature of the lubricant at the end portion of the fixing member in the axial direction is lower than a predetermined threshold value.

[0038] According to the invention of claim 11, the time from when the fixing process is instructed to start until the fixing process actually starts can be shortened compared to a case where the temperature of the lubricant is not adjusted.

[0039] According to the invention of technical solution 12, compared with the case where the temperature of the lubricant is not adjusted so that the difference between the temperature detected by one temperature detection unit and the temperature detected by other temperature detection units is less than a predetermined threshold value, the time from the indication of the start of the fixing process to the actual start of the fixing process can be shortened.

[0040] According to the invention of claim 13 , compared with a case where the rotation of the fixing member is controlled without considering the temperature of the lubricant, deformation of the fixing member caused by temperature variations of the lubricant can be suppressed.

[0041] According to the invention of claim 14 , compared with a case where the rotation of the fixing member is controlled without considering the temperature of the lubricant, deformation of the fixing member caused by temperature variations of the lubricant can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a diagram showing the overall structure of an image forming apparatus.

[0043] Figure 2 It is a diagram illustrating the configuration of the control unit.

[0044] Figure 3 This is a diagram illustrating the structure of the fixing device.

[0045] Figure 4 It is from Figure 3 A diagram showing the fixing belt, heat source, and temperature sensor as viewed in the direction indicated by arrow IV.

[0046] Figure 5 This is a diagram showing the flow of processing executed by the CPU provided in the control unit regarding the fixing process.

[0047] Figure 6 This is a diagram showing the temperature distribution of the lubricant.

[0048] Figure 7 This is a graph showing the viscosity of silicone oil and fluorine grease as examples of lubricants.

[0049] [Explanation of Symbols]

[0050] 1: Image forming device

[0051] 10: Image forming unit

[0052] 40: Fixing device

[0053] 120: Temperature sensor

[0054] 121: Central temperature sensor

[0055] 122: End temperature sensor

[0056] 401: CPU

[0057] 411: Fusing belt

[0058] 411B: Outer surface

[0059] 413: Heat Source

[0060] P: Paper DETAILED DESCRIPTION

[0061] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0062] Figure 1 1 is a diagram showing the overall structure of the image forming apparatus 1. Figure 1 This is a diagram when the image forming apparatus 1 is viewed from the front side (front surface side) of the image forming apparatus 1 .

[0063] The image forming apparatus 1 is a so-called tandem color printer.

[0064] The image forming apparatus 1 includes an image forming unit 10 as an example of an image forming device. The image forming unit 10 forms an image on a paper P as an example of a recording material based on image data of each color.

[0065] Furthermore, the image forming apparatus 1 is provided with a control unit 30 and an image processing unit 35. Furthermore, the image forming apparatus 1 is provided with a display device 90.

[0066] The display device 90 includes a touch panel and displays information. The display device 90 also receives information input from a user.

[0067] The control unit 30 controls each functional unit provided in the image forming apparatus 1. The image processing unit 35 performs image processing on image data from the personal computer (PC) 3 or the image reading device 4.

[0068] like Figure 2 As shown in the figure illustrating the structure of the control unit 30, the control unit 30 is provided with a central processing unit (CPU) 401 as an example of a processor, a random access memory (RAM) 402, a read-only memory (ROM) 403, and a storage device 404 including a hard disk.

[0069] The ROM 403 and the storage device 404 store programs executed by the CPU 401. The CPU 401 reads the programs stored in the ROM 403 or the storage device 404, and executes the programs using the RAM 402 as a work area.

[0070] The CPU 401 executes programs stored in the ROM 403 or the storage device 404 , thereby realizing various functions described below.

[0071] Here, the program executed by the CPU 401 can be provided to the image forming apparatus 1 in a state stored in a computer-readable recording medium such as a magnetic recording medium (a magnetic tape, a magnetic disk, etc.), an optical recording medium (an optical disk, etc.), a magneto-optical recording medium, or a semiconductor memory. Furthermore, the program executed by the CPU 401 can also be provided to the image forming apparatus 1 using a communication method such as the Internet.

[0072] In addition, in this embodiment, the so-called processor refers to a processor in a broad sense, including a general-purpose processor (such as a central processing unit (CPU)) or a special-purpose processor (such as a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic element, etc.).

[0073] Furthermore, the operations of the processors may be performed not only by a single processor but also by a plurality of processors located in physically isolated locations in collaboration. Furthermore, the order of the operations of the processors is not limited to that described in this embodiment and may be changed as appropriate.

[0074] Reference Figure 1 The image forming apparatus 1 will be further described.

[0075] The image forming section 10 is provided with four image forming units 11Y, 11M, 11C, and 11K (hereinafter also simply collectively referred to as “image forming units 11 ”) arranged in parallel with a fixed interval therebetween.

[0076] The image forming units 11 have the same configuration except for the toner stored in the developing unit 15. The image forming units 11 form toner images (images) of yellow (Y), magenta (M), cyan (C), and black (K).

[0077] Each image forming unit 11 is provided with a photosensitive drum 12 , a charger 200 for charging the photosensitive drum 12 , and a light emitting diode (LED) print head (LPH) 300 for exposing the photosensitive drum 12 .

[0078] The photosensitive drum 12 is charged by the charger 200 . The photosensitive drum 12 is then exposed by the LPH 300 , and an electrostatic latent image is formed on the photosensitive drum 12 .

[0079] Furthermore, each image forming unit 11 is provided with a developing device 15 for developing the electrostatic latent image formed on the photosensitive drum 12 and a cleaner (not shown) for cleaning the surface of the photosensitive drum 12 .

[0080] The image forming section 10 is provided with an intermediate transfer belt 20 to which the color toner images formed by the photosensitive drums 12 are transferred, and a primary transfer roller 21 that sequentially transfers (primarily transfers) the color toner images formed by the photosensitive drums 12 to the intermediate transfer belt 20 .

[0081] The image forming section 10 includes a secondary transfer roller 22 for collectively transferring (secondarily transferring) the toner images transferred onto the intermediate transfer belt 20 onto the paper P, and a fixing device 40 for fixing the toner images transferred onto the paper P onto the paper P.

[0082] The fixing device 40 is provided with a fixing belt module 41 including a heat source and a pressure roller 46 .

[0083] The fixing belt module 41 is arranged on the left side of the paper conveyance path R1 in the figure. The pressure roller 46 is arranged on the right side of the paper conveyance path R1 in the figure. The pressure roller 46 is pressed against the fixing belt module 41.

[0084] The fixing belt module 41 includes a film-shaped fixing belt 411 that is in contact with the paper P. The fixing belt 411 is a fixing member used to fix a toner image (image) on the paper P to the paper P.

[0085] The fixing belt 411 includes, for example, a release layer located on the outermost layer and in contact with the paper P, an elastic layer located on one inner side of the release layer, and a base layer supporting the elastic layer.

[0086] The fixing belt 411 is formed into an endless shape and is rotatably provided, rotating counterclockwise in the figure. In other words, the fixing belt 411 is formed into an endless shape and circulates along a predetermined path.

[0087] The fixing belt 411 contacts the paper P conveyed from below in the figure. More specifically, the fixing belt 411 has an outer peripheral surface 411B that contacts the paper P.

[0088] The portion of the fixing belt 411 that is in contact with the paper P moves together with the paper P. Furthermore, the fixing belt 411 and the pressure roller 46 sandwich the paper P, thereby applying pressure and heating the paper P.

[0089] Furthermore, in the fixing belt module 41 , a heat source (described later) for heating the fixing belt 411 is provided inside the fixing belt 411 .

[0090] The pressure roller 46 , an example of a pressure member, is disposed on the right side of the paper conveyance path R1 in the figure. The pressure roller 46 is pressed against the outer peripheral surface 411B of the fixing belt 411 and presses the paper P passing between the fixing belt 411 and the pressure roller 46 .

[0091] The pressure roller 46 is rotated clockwise in the figure by a motor (not shown). When the pressure roller 46 rotates clockwise, the fixing belt 411 receives a driving force from the pressure roller 46 and rotates counterclockwise.

[0092] In the image forming apparatus 1 , the image processing section 35 performs image processing on image data from the PC 3 or the image reading device 4 , and supplies the processed image data to each image forming unit 11 .

[0093] For example, in the black (K) image forming unit 11K, the photosensitive drum 12 is charged by the charger 200 while rotating in the direction of arrow A, and is exposed by the LPH 300 that emits light based on image data sent from the image processing unit 35 .

[0094] As a result, an electrostatic latent image related to a black (K) image is formed on the photosensitive drum 12 . The electrostatic latent image formed on the photosensitive drum 12 is developed by the developing device 15 , thereby forming a black (K) toner image on the photosensitive drum 12 .

[0095] Similarly, in the image forming unit 11Y, the image forming unit 11M, and the image forming unit 11C, toner images of yellow (Y), magenta (M), and cyan (C) are formed.

[0096] The color toner images formed by the image forming units 11 are sequentially electrostatically attracted by the primary transfer rollers 21 to the intermediate transfer belt 20 moving in the direction of arrow B, forming a toner image on the intermediate transfer belt 20 in which the color toners overlap.

[0097] The toner image formed on the intermediate transfer belt 20 is conveyed to the location of the secondary transfer roller 22 (secondary transfer section T) as the intermediate transfer belt 20 moves. The paper P is supplied from the paper storage section 1B to the secondary transfer section T at a timing corresponding to the toner image being conveyed to the secondary transfer section T.

[0098] In the secondary transfer portion T, the toner images on the intermediate transfer belt 20 are electrostatically transferred collectively to the conveyed paper P by a transfer electric field formed by the secondary transfer roller 22 .

[0099] Subsequently, the paper P to which the toner image has been electrostatically transferred is peeled off from the intermediate transfer belt 20 and conveyed to the fixing device 40 .

[0100] In the fixing device 40 , the paper P is sandwiched between the fixing belt module 41 and the pressure roller 46 . Specifically, the paper P is sandwiched between the fixing belt 411 that circulates counterclockwise and the pressure roller 46 that rotates clockwise.

[0101] As a result, the paper P is pressed and heated, and the toner image on the paper P is fixed to the paper P. Then, the paper P after fixing is conveyed to the paper loading portion 1E by the discharge rollers 500 .

[0102] Figure 3 This is a diagram illustrating the configuration of the fixing device 40 .

[0103] like Figure 3 As shown, the fixing device 40 is provided with a fixing belt module 41 and a pressure roller 46 .

[0104] The fixing belt module 41 is provided with a fixing belt 411 used for fixing the toner image to the paper P. The fixing belt 411 is pressed against the surface of the paper P on which the toner image is formed.

[0105] Here, in this embodiment, in order to improve the sliding between the fixing belt 411 and a heat source described later, a lubricant is applied to the inner peripheral surface 411D of the fixing belt 411 , and the lubricant adheres to the inner peripheral surface 411D of the fixing belt 411 .

[0106] Here, the type of lubricant is not particularly limited, and examples of the lubricant include silicone oil and fluorine grease.

[0107] The pressure roller 46 , which is an example of a pressure member, is pressed against the outer peripheral surface 411B of the fixing belt 411 , and presses the paper P passing between the fixing belt 411 and the pressure roller 46 .

[0108] Specifically, the pressure roller 46 is arranged in contact with the outer peripheral surface 411B of the fixing belt 411 , and forms a nip portion N, an area through which the paper P passes while being pressurized, between the pressure roller 46 and the fixing belt 411 .

[0109] In this embodiment, while the paper P passes through the nip portion N, the paper P is heated and pressurized, thereby fixing the toner image to the paper P.

[0110] A heat source 413 as an example of a heating member is provided inside the fixing belt 411 , and the heat source 413 heats the fixing belt 411 .

[0111] The heat source 413 is arranged so as to contact the inner peripheral surface 411D of the fixing belt 411. Furthermore, the heat source 413 is arranged so as to extend along the axial direction of the endless fixing belt 411. In other words, the heat source 413 is arranged along the axial direction of the fixing belt 411.

[0112] Furthermore, the heat source 413 is arranged so as to extend in a direction intersecting with the moving direction of the fixing belt 411. Figure 3 It is configured so as to extend in a direction perpendicular to the paper surface.

[0113] Here, the heat source 413 can be understood as a contact member that comes into contact with the fixing belt 411 .

[0114] Furthermore, a supporting member 440 that supports the heat source 413 is provided inside the fixing belt 411 . The supporting member 440 includes a supporting portion 441 that supports the heat source 413 .

[0115] Furthermore, a temperature sensor 120 as an example of a temperature detection unit is provided at a position facing one surface of the heat source 413 . The temperature sensor 120 detects the temperature of the lubricant adhering to the inner peripheral surface 411D of the fixing belt 411 .

[0116] More specifically, in this embodiment, the temperature sensor 120 is provided at a position facing the opposing surface 413N located on the opposite side to the opposing surface 413M facing the fixing belt 411 , among the surfaces of the heat source 413 .

[0117] In this embodiment, the temperature of the lubricant changes according to the temperature of the heat source 413 . In this embodiment, the temperature of the lubricant is detected by detecting the temperature of the heat source 413 .

[0118] Figure 4 It is from Figure 3 FIG. 4 is a diagram showing the fixing belt 411 , the heat source 413 , and the temperature sensor 120 as viewed from the direction indicated by arrow IV.

[0119] The heat source 413 includes a first heating element 413A and a second heating element 413B arranged along the longitudinal direction of the heat source 413 .

[0120] The first heating element 413A and the second heating element 413B are arranged so as to be positioned differently from each other in the moving direction of the fixing belt 411 .

[0121] The first heating element 413A has a heating portion H1. The heating portion H1 is located in the center of the longitudinal direction of the heat source 413. Hereinafter, in this specification, the heating portion H1 provided in the first heating element 413A is referred to as the "central heating portion H1."

[0122] The second heating element 413B includes a first heating portion H28 located at one longitudinal end 413E of the heat source 413 and a second heating portion H29 located at the other longitudinal end 413F of the heat source 413 .

[0123] Here, in this embodiment, the output (heating amount per unit time) of each of the first end heating portion H28 and the second end heating portion H29 is greater than the output (heating amount per unit time) of the central heating portion H1 provided in the first heating element 413A.

[0124] Furthermore, in this embodiment, a plurality of temperature sensors 120 are provided as the temperature sensor 120 .

[0125] Specifically, in this embodiment, a center temperature sensor 121 and an end temperature sensor 122 are provided as the temperature sensors 120 .

[0126] The center temperature sensor 121 and the end temperature sensor 122 are arranged at different positions in the axial direction of the fixing belt 411. In addition, the center temperature sensor 121 and the end temperature sensor 122 are arranged at different positions in the longitudinal direction of the heat source 413.

[0127] The center temperature sensor 121 is disposed at the center of the fixing belt 411 in the axial direction, and detects the temperature of the lubricant located at the center of the fixing belt 411 in the axial direction.

[0128] In addition, the central temperature sensor 121 is arranged at a position facing the longitudinal center of the heat source 413 , and detects the temperature of the lubricant at the position facing the longitudinal center of the heat source 413 .

[0129] The end portion temperature sensor 122 is disposed at one end portion 411E of the fixing belt 411 in the axial direction, and detects the temperature of the lubricant located at the one end portion 411E of the fixing belt 411 in the axial direction.

[0130] In addition, the end temperature sensor 122 is arranged at a position facing one longitudinal end 413E of the heat source 413 , and detects the temperature of the lubricant at the position facing one longitudinal end 413E of the heat source 413 .

[0131] The heat source 413 is formed in a plate shape and is provided along the moving direction of the fixing belt 411 and the width direction of the fixing belt 411 .

[0132] More specifically, the heat source 413 is as follows Figure 4 As shown, the shape when viewed from the front is a rectangle, and the longitudinal direction thereof is arranged along the width direction of the fixing belt 411 .

[0133] Here, the width direction of the fixing belt 411 is synonymous with the direction perpendicular to the moving direction of the fixing belt 411. Furthermore, the width direction of the fixing belt 411 is synonymous with the axial direction of the endless fixing belt 411.

[0134] Furthermore, in the present embodiment, the heat source 413 is arranged from one end portion 411E to the other end portion 411F in the axial direction of the fixing belt 411 .

[0135] In this embodiment, heat is supplied from the heat source 413 to the fixing belt 411 , thereby heating the fixing belt 411 .

[0136] Heat source 413 such as Figure 3As shown, it has: a facing surface 413M facing the fixing belt 411; an opposite surface 413N located on the opposite side to the facing surface 413M; and a side surface 413P connecting the facing surface 413M and the opposite surface 413N.

[0137] In this embodiment, the central temperature sensor 121 and the end temperature sensor 122 are provided at opposing positions of the opposite surface 413N.

[0138] Furthermore, in this embodiment, if Figure 3 As shown, the pressure roller 46 is pressed against the heat source 413 via the fixing belt 411 .

[0139] In this embodiment, the pressure roller 46 can advance and retract relative to the fixing belt module 41. When the fixing operation is not in progress, the pressure roller 46 is retracted from the fixing belt module 41. At this time, the fixing belt 411 and the pressure roller 46 are in a non-contact state.

[0140] Moreover, in this embodiment, if Figure 3 As shown, the support member 440 is provided with an upstream guide portion 445 and a downstream guide portion 446 .

[0141] The upstream guide portion 445 is located upstream of the heat source 413 in the rotational direction (movement direction) of the fixing belt 411. The upstream guide portion 445 contacts and guides a portion of the fixing belt 411 located upstream of the heat source 413.

[0142] The downstream-side guide portion 446 is located on the downstream side of the heat source 413 in the rotation direction of the fixing belt 411 .

[0143] The downstream guide portion 446 contacts a portion of the fixing belt 411 located downstream of the heat source 413 and guides the portion located downstream.

[0144] Furthermore, a support frame 490 as an internal member is provided in the fixing belt module 41. The support frame 490 is arranged inside the fixing belt 411 and supports the members arranged inside the fixing belt 411.

[0145] Specifically, the support frame 490 supports the support member 440 , the heat source 413 , and the like that are arranged inside the fixing belt 411 .

[0146] Figure 5 This is a diagram showing the flow of processing executed by the CPU 401 provided in the control unit 30 regarding the fixing process.

[0147] In this embodiment, when image formation starts, the CPU 401 first moves the pressure roller 46 (step S101 ) to press the pressure roller 46 against the fixing belt module 41 .

[0148] Next, the CPU 401 starts supplying power to the heat source 413 (supplying power to the first heating element 413A and the second heating element 413B) (step S102 ), causing the heat source 413 to generate heat.

[0149] Subsequently, the CPU 401 determines whether the difference between the temperature detected by the center temperature sensor 121 and the temperature detected by the end temperature sensor 122 (hereinafter sometimes simply referred to as “temperature difference”) is smaller than a predetermined threshold value X (step S103 ).

[0150] Then, if it is determined in step S103 that the temperature difference is smaller than the predetermined threshold value X, the CPU 401 starts rotating the fixing belt 411 (step S104 ).

[0151] More specifically, the CPU 401 starts driving and rotating the pressure roller 46 to start rotating the fixing belt 411 .

[0152] Here, in this embodiment, the CPU 401 controls the rotation of the fixing belt 411 based on the temperature detected by the temperature sensor 120 .

[0153] More specifically, as described above, if the temperature difference is smaller than the predetermined threshold value X, the CPU 401 starts the rotation of the fixing belt 411 .

[0154] Here, if the lubricant temperature varies in the axial direction of the fixing belt 411 , the fixing belt 411 moves easily in areas where the lubricant temperature is high, and moves less easily in areas where the lubricant temperature is low.

[0155] More specifically, in areas where the lubricant temperature is high, sliding between the heat source 413 and the fixing belt 411 is likely to occur, and the fixing belt 411 becomes easy to move, while in areas where the lubricant temperature is low, sliding between the heat source 413 and the fixing belt 411 is difficult to occur, and the fixing belt 411 becomes difficult to move.

[0156] More specifically, in the present embodiment, the amount of heat dissipated at the axial end portions of the fixing belt 411 is greater than the amount of heat dissipated at the axial center portion of the fixing belt 411 .

[0157] At this time, if Figure 6 As shown in (Diagram Showing Temperature Distribution of Lubricant), the temperature of the lubricant at the axial end portions of the fixing belt 411 is lower than the temperature of the lubricant at the axial center portion of the fixing belt 411 .

[0158] At this time, the fixing belt 411 becomes difficult to move at the ends of the fixing belt 411 in the axial direction, and deformation of the fixing belt 411 , for example, twisting of the fixing belt 411 , is likely to occur.

[0159] Furthermore, when the fixing belt 411 is deformed, the fixing belt 411 may be damaged or the quality of the image fixed to the paper P may be degraded.

[0160] In contrast, in the configuration of the embodiment, the rotation of the fixing belt 411 is started under a condition where the temperature variation of the lubricant is small, and deformation of the fixing belt 411 due to the temperature variation of the lubricant is suppressed.

[0161] Furthermore, at this time, damage to the fixing belt 411 or degradation of image quality is suppressed.

[0162] In addition, in the fixing device 40 of this embodiment, immediately after the first heating element 413A (see Figure 4 ), after the second heating element 413B is powered, it is in the state where the temperature difference is large.

[0163] However, in this embodiment, the outputs of the first end heating portion H28 and the second end heating portion H29 are greater than the output of the central heating portion H1 , and the temperature difference decreases over time.

[0164] In addition, in this embodiment, as time passes, the temperature of the lubricant at the end portions of the fixing belt 411 becomes closer to the temperature of the lubricant at the center portion of the fixing belt 411 , and the temperature difference becomes smaller.

[0165] Furthermore, in this embodiment, as described above, when the temperature difference becomes smaller than the predetermined threshold value X, the rotation of the fixing belt 411 is started.

[0166] This suppresses deformation of the fixing belt 411 , thereby suppressing damage to the fixing belt 411 or degradation in image quality due to the deformation of the fixing belt 411 .

[0167] In addition, in this embodiment, the case where the rotation of the fixing belt 411 is started when the temperature difference becomes smaller than the predetermined threshold value X is described as an example.

[0168] However, in addition to this, the rotation speed of the fixing belt 411 may be increased when the temperature difference becomes smaller than a predetermined threshold value X.

[0169] Here, when the process of increasing the rotation speed of the fixing belt 411 is performed, for example, in step S101 (see Figure 5 ) is completed, the fixing belt 411 starts rotating at a low speed.

[0170] Then, if it is determined in step S103 that the temperature difference has become smaller than the predetermined threshold value X, the rotation speed of the fixing belt 411 is increased. In other words, the speed of the fixing belt 411 is increased.

[0171] At this time, deformation of the fixing belt 411 due to the increased speed of the fixing belt 411 is also suppressed, thereby suppressing damage to the fixing belt 411 or degradation in image quality due to the increased speed of the fixing belt 411.

[0172] Furthermore, when a grease-based lubricant is used as the lubricant instead of an oil-based lubricant, deformation of the fixing belt 411 is more likely to occur.

[0173] Figure 7 This is a graph showing the viscosity of silicone oil and fluorine grease as examples of lubricants.

[0174] Both silicone oil and fluorinated grease increase in viscosity as the temperature decreases, but the rate of increase in viscosity of fluorinated grease at lower temperatures is greater than that of silicone oil.

[0175] In this case, if fluorinated grease is used as the lubricant, as described above, when a temperature difference occurs, the fixing belt 411 becomes partially less likely to move than when silicone oil is used. Furthermore, in this case, the fixing belt 411 is more likely to deform.

[0176] Furthermore, the image forming apparatus 1 according to the present embodiment is configured such that the predetermined threshold value X can be changed.

[0177] More specifically, in this embodiment, the display device 90 (see Figure 1 ), a screen (not shown) for changing the threshold value X is displayed. Then, the user inputs a new threshold value X on this screen, thereby changing the predetermined threshold value X.

[0178] Alternatively, the threshold value X may be changed by the CPU 401. In this case, the threshold value X is automatically changed.

[0179] When the CPU 401 changes the threshold value X, the CPU 401 changes the threshold value X based on, for example, information related to the usage time of the fixing device 40 .

[0180] Here, "information related to usage time" is not limited to the operating time of the fixing device 40. "Information related to usage time" includes information other than the operating time, whose value increases according to the usage time of the fixing device 40, such as the number of sheets of paper P that have been fixed by the fixing device 40.

[0181] Here, when the CPU 401 changes the threshold value X based on information related to the usage time of the fixing device 40 (hereinafter referred to as “usage time information”), the CPU 401 makes the threshold value X smaller than when the value determined based on the usage time information exceeds a predetermined value.

[0182] Here, the viscosity of the lubricant may increase with the use time of the fixing device 40 , and in this case, the fixing belt 411 is more likely to be deformed.

[0183] More specifically, as the fixing device 40 ages, the amount of paper dust and other substances mixed into the lubricant increases, and accordingly, the viscosity of the lubricant increases, making it more likely that the fixing belt 411 will deform. Furthermore, in areas where the lubricant temperature is low, the fixing belt 411 becomes more difficult to move, making it more likely that the fixing belt 411 will deform.

[0184] In this case, as described above, if the CPU 401 reduces the threshold value X, the fixing belt 411 starts rotating or speeding up when the temperature unevenness of the lubricant is smaller.

[0185] In the above description, the center temperature sensor 121 and the end temperature sensor 122 detect the temperature of the heat source 413 , which is a member in contact with the lubricant, to thereby detect the temperature of the lubricant.

[0186] More specifically, the heat source 413 is a heating member that heats the fixing belt 411 , and the center temperature sensor 121 and the end temperature sensor 122 detect the temperature of the heating member to thereby detect the temperature of the lubricant.

[0187] However, the present invention is not limited thereto, and the temperature sensor 120 may be disposed in a manner such that the temperature sensor 120 directly contacts the lubricant to directly detect the temperature of the lubricant.

[0188] More specifically, for example, the inner peripheral surface 411D (see Figure 3 ) are arranged at opposite positions to directly detect the temperature of the lubricant attached to the inner peripheral surface 411D.

[0189] Furthermore, in addition to this, the temperature of the lubricant may be detected in a non-contact manner using so-called thermography or the like.

[0190] Furthermore, the above description describes the case where the fixing belt 411 is rotated or accelerated when the difference between the temperature detected by the center temperature sensor 121 and the temperature detected by the end temperature sensor 122 is smaller than the predetermined threshold value X.

[0191] Incidentally, the description has been made of the case where, when the temperature difference between the two temperatures is smaller than the predetermined threshold value X, the rotation of the fixing belt 411 or the speed increase of the fixing belt 411 is performed.

[0192] However, the present invention is not limited thereto, and the rotation of the fixing belt 411 may be controlled by further adding a condition that the fixing belt 411 is rotated or accelerated when the lower of the two temperatures is greater than a predetermined threshold.

[0193] In other words, the fixing belt 411 may be rotated or accelerated when the difference between the temperature detected by the central temperature sensor 121 and the temperature detected by the end temperature sensor 122 is less than a predetermined threshold value X, and the lower temperature of the two temperatures is greater than a predetermined threshold value (a threshold value that is different from the threshold value X).

[0194] Even when the difference between the two temperatures is small, if the two temperatures are low, the viscosity of the lubricant is high, and the fixing belt 411 is difficult to rotate.

[0195] As described above, if the fixing belt 411 is rotated or accelerated at a lower temperature greater than a predetermined threshold, the fixing belt 411 is rotated or accelerated at a higher temperature of the lubricant.

[0196] Furthermore, the above description has been made of the case where whether to rotate the fixing belt 411 or to increase the speed of the fixing belt 411 is determined based on the two temperatures detected by the center temperature sensor 121 and the temperature detected by the end temperature sensor 122 .

[0197] The present invention is not limited thereto, and for example, whether to rotate the fixing belt 411 or to increase the speed of the fixing belt 411 may be determined based only on the temperature detected by the end temperature sensor 122 .

[0198] In other words, the CPU 401 may determine whether to rotate the fixing belt 411 or to increase the speed of the fixing belt 411 based only on the temperature of the lubricant at the axial end portions of the fixing belt 411 .

[0199] More specifically, at this time, when the temperature of the lubricant at the axial end portion of the fixing belt 411 is higher than a predetermined threshold value, the CPU 401 starts rotating the fixing belt 411 or increases the rotation speed of the fixing belt 411 .

[0200] Here, in this embodiment, the outputs of the first end heating portion H28 and the second end heating portion H29 located at the axial end portions of the fixing belt 411 are greater than the output of the central heating portion H1 .

[0201] At this time, if the temperature of the lubricant at the axial end portion of the fixing belt 411 rises and becomes higher than a predetermined threshold value, it is expected that the temperature difference has become smaller.

[0202] Therefore, the rotation of the fixing belt 411 or the speed increase of the fixing belt 411 may be performed based only on the temperature of the lubricant at the axial end portions of the fixing belt 411 , not necessarily based on the temperature difference.

[0203] Furthermore, in addition to this, the CPU 401 may further adjust the temperature of the lubricant when a specific condition is satisfied, for example, when the paper P is not being conveyed.

[0204] More specifically, the CPU 401 may also perform the first heating element 413A (see Figure 4 ), the temperature of the lubricant is adjusted by controlling the second heating element 413B so that the difference between the temperature detected by the central temperature sensor 121 and the temperature detected by the end temperature sensor 122 is less than a predetermined threshold value.

[0205] More specifically, when the CPU 401 has not yet received the start instruction for image formation and has not yet conveyed the paper P, it controls the first heating element 413A and the second heating element 413B while rotating the fixing belt 411, or controls the first heating element 413A and the second heating element 413B while stopping the rotation of the fixing belt 411.

[0206] More specifically, CPU 401 controls the first heating element 413A and the second heating element 413B so that the difference between the temperature detected by the central temperature sensor 121 and the temperature detected by the end temperature sensor 122 is less than a predetermined threshold value (which may be the same as the threshold value X or another threshold value).

[0207] More preferably, the CPU 401 controls the first heating element 413A and the second heating element 413B so that the difference between the temperature detected by the central temperature sensor 121 and the temperature detected by the end temperature sensor 122 is less than a predetermined threshold, and the lower of the two temperatures is greater than a predetermined threshold.

[0208] Therefore, in this case, when an instruction to start image formation is subsequently issued, image formation can be performed as quickly as possible. Furthermore, while the present invention has been described with reference to an electrophotographic image forming apparatus, it is not limited to electrophotographic image forming apparatuses and is also applicable, for example, to inkjet image forming apparatuses. Inkjet image forming apparatuses hold an undried image (unfixed ink image) formed by ink and contact it with a conveyed sheet of paper, thereby fixing the unfixed ink image to the paper.

Claims

1. A fixing device comprising: a fixing member formed in an annular shape and rotatably provided, having an outer peripheral surface in contact with a recording material, and used for fixing an image on the recording material to the recording material; a contact member configured to contact the inner peripheral surface of the fixing member and extend along the axial direction of the annular fixing member; a temperature detecting portion for detecting a temperature of the lubricant adhering to the inner peripheral surface of the fixing member; as well as a processor that controls the rotation of the fixing member based on the temperature detected by the temperature detection portion, The temperature detection portion is provided in plurality and is arranged at positions different from each other in the axial direction. The processor starts rotating the fixing member or increases the rotation speed of the fixing member when a difference between a temperature detected by one of the temperature detecting portions and a temperature detected by the other temperature detecting portion is smaller than a predetermined threshold value.

2. The fixing device according to claim 1, wherein The temperature detecting portion detects the temperature of a member in contact with the lubricant to detect the temperature of the lubricant.

3. The fixing device according to claim 2, wherein The contact member is a heating member that heats the fixing member. The temperature detection unit detects the temperature of the heating member to thereby detect the temperature of the lubricant.

4. The fixing device according to claim 1, wherein The processor starts rotating the fixing member or increases the rotation speed of the fixing member when a lower temperature between the temperature detected by one temperature detecting portion and the temperature detected by the other temperature detecting portion is greater than a predetermined threshold value.

5. The fixing device according to claim 1, wherein When the difference between the temperature detected by the temperature detection portion arranged at the end portion of the fixing member in the axial direction and the temperature detected by the temperature detection portion arranged at the center portion of the fixing member in the axial direction is less than a predetermined threshold value, the processor starts rotating the fixing member or increases the rotation speed of the fixing member.

6. The fixing device according to claim 1, wherein The predetermined threshold value is configured to be changeable.

7. The fixing device according to claim 6, wherein The processor changes the threshold value based on information related to usage time of the fixing device.

8. The fixing device according to claim 7, wherein When a value determined based on information related to the usage time of the fixing device exceeds a predetermined value, the processor reduces the threshold value compared to a case where the value does not exceed the predetermined value.

9. The fixing device according to claim 1, wherein The processor starts rotating the fixing member or increases the rotation speed of the fixing member when the temperature of the lubricant at the end portion of the fixing member in the axial direction is greater than a predetermined threshold value.

10. The fixing device according to claim 1, wherein The processor further performs temperature adjustment of the lubricant.

11. The fixing device according to claim 10, wherein The processor adjusts the temperature of the lubricant so that a difference between a temperature detected by one of the temperature detection units and a temperature detected by the other temperature detection units is smaller than a predetermined threshold value.

12. An image forming apparatus comprising: An image forming component that forms an image on a recording material; a fixing member formed in an annular shape and rotatably provided, having an outer peripheral surface in contact with a recording material on which an image is formed by the image forming unit, and used for fixing the image on the recording material to the recording material; a contact member configured to contact the inner peripheral surface of the fixing member and extend along the axial direction of the annular fixing member; a temperature detecting portion for detecting a temperature of the lubricant adhering to the inner peripheral surface of the fixing member; as well as a processor that controls the rotation of the fixing member based on the temperature detected by the temperature detection portion, The temperature detection portion is provided in plurality and is arranged at positions different from each other in the axial direction. The processor starts rotating the fixing member or increases the rotation speed of the fixing member when a difference between a temperature detected by one of the temperature detecting portions and a temperature detected by the other temperature detecting portion is smaller than a predetermined threshold value.

Images