Fixing device and image forming device

Abstract

The present invention discloses a fixing device and an image forming device, which can maintain the sliding property of a fixing belt for a long time. The fixing device involved in this embodiment is a fixing device that fixes a colorant image formed on a medium to the medium, and is provided with a heating rotating body, a heater, a pressing component, a pressurizing rotating body, and a lubricant retaining component. The heating rotating body is supported to be rotatable. The heater heats the heating rotating body. The pressing component is arranged inside the heating rotating body. The pressurizing rotating body is pressed by the pressing component via the heating rotating body, forming a gap for the medium to pass through. The lubricant retaining component is added with a second lubricant of a second viscosity higher than the first viscosity, and abuts against the inner peripheral surface of the heating rotating body.

Description

Technical Field

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

[0002] Image forming devices such as multifunction machines and laser printers are equipped with a fixing device for fixing a toner image on a sheet of paper. The fixing device transfers heat from a heater to the sheet of paper via, for example, a fixing belt, thereby fixing the toner image transferred to the sheet of paper on the sheet of paper. Thus, printing of images, text, etc. on the sheet of paper is achieved.

[0003] In this fixing device, the pressure roller is pressed against the pressure pad disposed on the inner side of the fixing belt via the fixing belt, thereby forming a gap for the paper to pass through between the fixing belt and the pressure roller. Therefore, when the paper passes through the gap, if the fixing belt and the pressure roller rotate, the inner peripheral surface of the fixing belt slides relative to the pressure pad. Therefore, a lubricant such as silicone oil is applied to the inner peripheral surface of the fixing belt. This reduces the friction resistance of the fixing belt.

[0004] However, the silicone oil may leak from the end of the fixing belt, or the silicone oil may be vaporized and reduced due to heating of the fixing belt. As a result, the sliding property of the fixing belt gradually decreases with the operation of the device. Therefore, various technologies have been proposed for suppressing the decrease in the sliding property of the fixing belt by supplying lubricant to the inner peripheral surface of the fixing belt during the operation of the device. Summary of the invention

[0005] In the prior art, since lubricant is applied to the inner peripheral surface of the fixing belt by a lubricant supplying member, the reduction in the sliding property of the fixing belt can be suppressed. However, the viscosity of the lubricant decreases due to heating, and it becomes easy to leak out from the inner peripheral surface of the fixing belt. Therefore, if the working time of the fixing device becomes longer, there is a situation where the lubricant is insufficient. In addition, if a high-viscosity grease is used as a lubricant, the outflow of the lubricant can be suppressed, but there is a problem that the viscosity resistance increases and the sliding property decreases.

[0006] The present invention has been made in view of the above circumstances, and therefore an object of the present invention is to maintain the sliding property of the fixing belt for a long period of time.

[0007] In order to solve the above-mentioned problems, the fixing device involved in this embodiment is a fixing device that fixes the colorant image formed on the medium to the medium, and comprises: a heating rotating body supported so as to be rotatable; a heater that heats the heating rotating body; a pressing member that is arranged inside the heating rotating body; a pressurizing rotating body that is pressed by the pressing member via the heating rotating body to form a gap for the medium to pass through; and a lubricant retaining member that is added with a first lubricant of a first viscosity and a second lubricant of a second viscosity higher than the first viscosity, and abuts against the inner circumferential surface of the heating rotating body.

[0008] The image forming device involved in this embodiment includes: a colorant image forming unit that forms a colorant image; a transfer body that transfers the colorant image to a medium; and the above-mentioned fixing device that heats the medium to which the colorant image is transferred by the transfer body, thereby fixing the colorant image to the medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a diagram schematically showing the configuration of the image forming apparatus according to the present embodiment.

[0010] Figure 2 It is a diagram showing an enlarged view of the image forming section.

[0011] Figure 3 This is a diagram showing an example of a fixing device.

[0012] Figure 4 This is a perspective view showing the fixing device with the fixing belt omitted.

[0013] Figure 5 It is a top view of the lubricant retaining member mounted on the base member.

[0014] Figure 6 This is a block diagram of a control system constituting the image forming apparatus.

[0015] Figure 7 It is a perspective view showing a lubricant retaining member according to a modified example.

[0016] Figure 8 It is a perspective view showing a lubricant retaining member according to a modified example.

[0017] Fig. 9 It is a diagram showing a fixing device according to a modified example.

[0018] Description of Reference Numerals

[0019] 10…image forming device; 11…main body; 12…document table; 13…automatic document feeder; 14…operation panel; 15…scanner; 16…image sensor; 17…image forming unit; 18…paper supply box; 18a…pick-up roller; 19C, 19K, 19M, 19Y…scanner head; 20C, 20K, 20M, 20Y…image forming unit; 21…intermediate transfer belt; 22…photosensitive drum; 23…charger; 24…developer; 24a…developer roller; 25…primary transfer roller; 26…cleaner; 27…scraper; 31…drive roller; 32…driven roller; 33…secondary transfer roller; 34…belt cleaner; 35…paper supply roller; 37…paper discharge roller; 38…paper discharge unit; 50, 50A…fixing device; 51…fixing belt; 52… Pressure roller; 52a…core material; 52b…silicone rubber layer; 60…heating roller; 61…halogen heater; 62…ceramic heater; 80…base member; 81…pressure pad; 81a…sliding sheet; 90, 901, 902…lubricant retaining member; 91…recess; 92…gap; 100…CPU; 110…bus; 120…read-only memory (ROM); 121…random access memory (RAM); 122…interface; 123…input-output control circuit; 130…transport control circuit; 131…motor group; 132…sensor; 140…image formation control circuit; 150…fixing control circuit; 151…drive motor; 152…sensor; 153…thermostat; 501…drive roller 502…tension roller; P…paper. DETAILED DESCRIPTION

[0020] Hereinafter, the image forming apparatus according to the present embodiment will be described with reference to the drawings. In the description, an XYZ coordinate system consisting of an X axis, a Y axis, and a Z axis that are orthogonal to each other is used as appropriate.

[0021] Figure 1 This is a diagram schematically showing the structure of the image forming device 10 involved in the present embodiment. The image forming device 10 is, for example, a multi-function peripheral (MFP). The image forming device 10 is composed of a main body 11 and an automatic document feeder (ADF) 13 arranged above the main body 11. A document table 12 formed of transparent glass is arranged on the upper part of the main body 11, and the automatic document feeder (ADF) 13 is provided on the upper surface side of the document table 12 in a manner that allows it to rise and fall and rotate. In addition, an operation panel 14 is provided on the upper part of the main body 11. The operation panel 14 has various keys and a GUI (Graphical User Interface) and the like.

[0022] A scanner 15 for reading a document is provided below the document table 12 . The scanner 15 reads a document fed by the automatic document feeder 13 or a document placed on the document table 12 to generate image data. The scanner 15 includes an image sensor 16 .

[0023] When reading the image of the document placed on the document table 12, the image sensor 16 moves in the +X direction along the document table 12 while reading the image of the document. When reading the image of the document fed to the document table 12 by the automatic document feeder 13, the image sensor 16 is fixed to the Figure 1 The image of each document fed sequentially is read at the position shown.

[0024] An image forming unit 17 is disposed inside the main body 11. The image forming unit 17 forms a toner image on a recording medium such as paper stored in a paper feed cassette 18 based on image data read by the scanner 15 or image data created by a personal computer or the like.

[0025] The image forming unit 17 includes: image forming units 20Y, 20M, 20C, 20K that form latent images using yellow (Y), magenta (M), cyan (C), and black (K) colorants; scanning heads 19Y, 19M, 19C, 19K that are provided corresponding to the image forming units; and an intermediate transfer belt 21, etc.

[0026] The image forming units 20Y, 20M, 20C, and 20K are arranged below the intermediate transfer belt 21. The image forming units 20Y, 20M, 20C, and 20K are arranged from the -X side to the +X side in the image forming unit 17. The scanning heads 19Y, 19M, 19C, and 19K are arranged below the image forming units 20Y, 20M, 20C, and 20K, respectively.

[0027] Figure 2 20K is an enlarged view showing the image forming unit 20K among the image forming units 20Y, 20M, 20C, and 20K. The image forming units 20Y, 20M, 20C, and 20K have the same structure. Therefore, the structure of each image forming unit will be described by taking the image forming unit 20K as an example.

[0028] The image forming unit 20K has a photosensitive drum 22 as an image carrier. A charger 23, a developer 24, a primary transfer roller 25, a cleaner 26, and the like are arranged around the photosensitive drum 22 in the direction indicated by the arrow t. Laser light is irradiated from the scanner head 19K to the exposure position of the photosensitive drum 22. By irradiating the surface of the rotating photosensitive drum 22 with laser light, an electrostatic latent image is formed on the surface of the photosensitive drum 22.

[0029] The charging charger 23 of the image forming unit 20K uniformly charges the surface of the photosensitive drum 22. The developing unit 24 supplies toner to the photosensitive drum 22 through the developing roller 24a to which a developing bias is applied, thereby developing the electrostatic latent image. The cleaner 26 peels off and removes the residual toner on the surface of the photosensitive drum 22 using the scraper 27. The toner peeled off by the scraper 27 is recovered by the cleaner 26.

[0030] like Figure 1 As shown in FIG. 1 , the intermediate transfer belt 21 is stretched by a driving roller 31 and three driven rollers 32. The driving roller 31 rotates so that the intermediate transfer belt 21 is moved to the Figure 1 In addition, if Figure 1 As shown, the intermediate transfer belt 21 contacts the upper surface of each of the photosensitive drums 22 of the image forming units 20Y, 20M, 20C, and 20K. A primary transfer voltage is applied to the intermediate transfer belt 21 at a position facing the photosensitive drum 22 by the primary transfer roller 25. Thus, the toner image developed on the surface of the photosensitive drum 22 is primarily transferred to the intermediate transfer belt 21.

[0031] The secondary transfer roller 33 is disposed opposite to the driving roller 31 on which the intermediate transfer belt 21 is stretched. When the paper P passes between the driving roller 31 and the secondary transfer roller 33, the secondary transfer voltage is applied to the paper P by the secondary transfer roller 33. As a result, the toner image formed on the intermediate transfer belt 21 is secondarily transferred to the paper P. In the vicinity of the driven roller 32 of the intermediate transfer belt 21, as shown in FIG. Figure 1 As shown in FIG. 1 , a belt cleaner 34 is provided. The belt cleaner 34 removes residual toner on the surface of the intermediate transfer belt 21.

[0032] like Figure 1 As shown, a paper feed roller 35 is provided between the paper feed cassette 18 and the secondary transfer roller 33. The paper P taken out from the paper feed cassette 18 by a pickup roller 18a disposed near the paper feed cassette 18 is conveyed between the intermediate transfer belt 21 and the secondary transfer roller 33 by the paper feed roller 35.

[0033] A fixing device 50 is provided above the secondary transfer roller 33. In addition, a paper discharge roller 37 is provided above the fixing device 50. The paper P that has passed through the intermediate transfer belt 21 and the secondary transfer roller 33 is heated by the fixing device 50. Thus, the toner image is fixed on the paper P. The paper P that has passed through the fixing device 50 is discharged to the paper discharge section 38 by the paper discharge roller 37.

[0034] Figure 3 : is a diagram showing an example of the fixing device 50. The fixing device 50 includes a heating roller 60, a base member 80, a pressure pad 81 supported by the base member 80, a fixing belt 51 wound around the heating roller 60 and the pressure pad 81, a pressure roller 52, a lubricant retaining member 90, and the like.

[0035] Figure 4 The fixing belt 51 is omitted and shown Figure 3 3D view of the fixing device 50 shown in FIG. 6A. The heating roller 60 is a cylindrical member whose length direction is the Y-axis direction. The heating roller 60 is about 35 cm long and about 20 mm in diameter, and is formed of a metal with high thermal conductivity such as aluminum. The heating roller 60 is supported so as to be rotatable around an axis parallel to the Y-axis. A halogen heater 61, for example, is disposed inside the heating roller 60. The length of the halogen heater 61 in the Y-axis direction is substantially equal to the length of the heating roller 60 in the Y-axis direction.

[0036] The base member 80 is a member having a U-shaped XZ cross section with its longitudinal direction being the Y-axis direction. The base member 80 is made of, for example, iron or stainless steel. The base member 80 is substantially equal in length to the heating roller 60 and is horizontally supported parallel to the Y-axis.

[0037] The pressure pad 81 is a component whose length direction is the Y-axis direction. The length of the pressure pad 81 is equal to the length of the heating roller 60, and is made of elastic materials such as silicone rubber, fluororubber, polyimide resin, polyphenylene sulfide resin (PPS), polyethersulfone resin (PES), liquid crystal polymer (LCP), phenolic resin (PF) and other heat-resistant resins. On the surface of the pressure pad 81, for example Figure 3 As shown in FIG. 8 , a sliding sheet 81a having a small friction resistance may be provided to cover the surface of the pressure pad 81. As the sliding sheet 81a, for example, glass cloth impregnated with fluorine resin may be used.

[0038] The fixing belt 51 is an endless belt shaped into a cylindrical shape with its length direction being the Y-axis direction. The length of the fixing belt 51 in the Y-axis direction is substantially equal to the length of the heating roller 60 and is larger than the width (dimension in the Y-axis direction) of the paper P. The fixing belt 51 is wound around the heating roller 60 and the pressure pad 81. By applying force to the heating roller 60 in the -X direction, the fixing belt 51 is stretched with a certain tension.

[0039] The fixing belt 51 has a thickness of about 300 μm. The fixing belt 51 has a base made of, for example, a heat-resistant polyimide film with a thickness of 70 μm. For example, a metal layer, a composite functional layer, an elastic layer, and a protective layer are laminated on the surface of the base.

[0040] The metal layer is a layer formed of a metal such as copper and SUS, and the composite functional layer is a layer formed of nickel. The elastic layer is a layer formed of silicone rubber having a thickness of about 200 μm. The elastic layer is covered with a protective layer formed of a PFA resin (perfluoroalkoxy resin) or the like. In order to shorten the preheating time of the fixing device 50, the thickness of the elastic layer and the protective layer is adjusted so that the heat capacity does not become too large. Silicone oil is applied as a lubricant on the inner peripheral surface of the fixing belt 51.

[0041] like Figure 4 As shown in the figure, the pressure roller 52 is a cylindrical member with the longitudinal direction being the Y-axis direction. The pressure roller 52 includes a core material 52a formed of a metal such as aluminum and a silicone rubber layer 52b laminated on the outer peripheral surface of the core material. The surface of the silicone rubber layer 52b is covered with a PFA resin (perfluoroalkoxy resin). The outer diameter of the pressure roller 52 is, for example, about 30 mm, and the length is substantially equal to the width of the fixing belt 51.

[0042] The pressure roller 52 is supported to be rotatable around the core material 52a, and is biased in the -X direction by, for example, the elastic force of a spring. As a result, the pressure roller 52 abuts against the pressure pad 81 via the fixing belt 51. When the pressure roller 52 abuts against the pressure pad 81 via the fixing belt 51, a gap is formed between the pressure roller 52 and the fixing belt 51 for the paper P to pass through.

[0043] The lubricant retaining member 90 is formed of a material that has liquid absorption and elastic deformation. The lubricant retaining member 90 is bonded to the lower surface (surface on the -Z side) of the base member 80 by, for example, an adhesive. The lubricant retaining member 90 is a member whose length direction is set to the Y-axis direction, and the length in the Y-axis direction is equal to the length of the fixing belt 51. In addition, the width (dimension in the X-axis direction) of the lubricant retaining member 90 is, for example, about 1 cm to 2 cm, and the thickness is, for example, about 3 mm to 5 mm. The lubricant retaining member 90 is formed of a material with high liquid absorption and heat resistance, such as aramid fiber, melamine resin, glass fiber, etc.

[0044] A rectangular recess 91 and a slit 92 whose longitudinal direction is the X-axis direction are formed from the outer edge to the center of the lubricant retaining member 90 on the +X side. Except for the slits 92 formed at both ends of the lubricant retaining member 90 in the Y-axis direction, the recesses 91 and the slits 92 are alternately formed along the Y-axis.

[0045] Figure 5 FIG. 8 is a top view of the lubricant retaining member 90 mounted on the base member 80. Figure 5 As shown, the colored portion of the lubricant retaining member 90 is impregnated with oil as a first lubricant, and the colored portion inside the recess 91 is filled with grease as a second lubricant. The second lubricant in the recess 91 is retained by the lubricant retaining member 90 .

[0046] As the first lubricant oil, silicone oil having a viscosity of about 100 cs at 100 degrees can be used. Also, as the second lubricant grease, a lubricant having a viscosity of about 200 cs to 300 cs and having a base oil of, for example, synthetic oil can be used.

[0047] like Figure 3As shown in FIG. 1 , the lubricant retaining member 90 configured as described above is attached to the lower surface of the base member 80, thereby being in contact with the inner peripheral surface of the fixing belt 51. In this state, the lubricant retaining member 90 is elastically deformed, and the contact surface that contacts the fixing belt 51 is pressed against the fixing belt 51 by the elastic force of the lubricant retaining member 90.

[0048] In the fixing device 50, the heating roller 60 is heated by energizing the halogen heater 61. The heating roller 60 functions as a heater for the fixing belt 51, and heats and raises the temperature of the fixing belt 51. Figure 3 The paper P is conveyed through the gap between the pressure roller 52 and the fixing belt 51 which rotate in the directions indicated by the arrows. Thus, the paper P is heated by the fixing belt 51 which is heated, so that the toner image formed on the paper P is fixed on the paper P.

[0049] When the fixing belt 51 rotates, the first lubricant impregnated in the lubricant retaining member 90 is applied to the entire inner peripheral surface of the fixing belt 51. In addition, the second lubricant added to the recessed portion 91 is applied to the region A1 of the inner peripheral surface of the fixing belt 51 passing through the recessed portion 91.

[0050] Figure 6 1 is a block diagram of a control system constituting the image forming apparatus 10. The control system includes, for example, a CPU 100 for controlling the entire image forming apparatus, a bus 110, a read-only memory (ROM) 120, a random access memory (RAM) 121, an interface 122, a scanner 15, an input / output control circuit 123, a paper feed / transport control circuit 130, an image forming control circuit 140, and a fixing control circuit 150. The CPU 100 and each circuit are connected via the bus 110.

[0051] The ROM 120 stores a control program and control data that define basic operations of image forming processing.

[0052] The RAM 121 functions as a work memory serving as a work area for the CPU 100 .

[0053] The CPU 100 executes the program stored in the ROM 120. Thus, the CPU 100 generally controls each unit constituting the image forming apparatus 10, and sequentially executes processing for forming an image on a sheet.

[0054] The interface 122 communicates with a terminal or other device used by the user. The input / output control circuit 123 displays information on the operation panel 14 or receives input from the operation panel 14. The user of the image forming apparatus 10 can specify, for example, paper size, the number of copies of a document, etc. by operating the operation panel 14.

[0055] The paper feed / transport control circuit 130 is a unit that controls a motor group 131 that drives the pickup roller 18a, the paper feed roller 35, or the paper discharge roller 37 of the transport path. The paper feed / transport control circuit 130 controls the motor group 131 based on a control signal from the CPU 100 and detection results of various sensors 132 provided near the paper feed cassette 18 or in the transport path.

[0056] The image formation control circuit 140 controls the photoconductive drum 22 , the charger 23 , the scanner heads 19Y, 19M, 19C, and 19K, the developer 24 , and the primary transfer roller 25 based on control signals from the CPU 100 .

[0057] The fixing control circuit 150 controls the drive motor 151 that rotates the pressure roller 52 of the fixing device 50 based on the control signal from the CPU 100, and drives the halogen heater 61 based on the output from the sensor 152 that detects the temperature of the fixing belt 51, the size of the paper P notified from the CPU, etc. In addition, the fixing control circuit 150 stops the operation of the fixing device 50 based on the signal from the thermostat 153 that monitors the overheating of the fixing belt 51.

[0058] The image forming apparatus 10 uses a print command from the user as a trigger to perform image forming processing for printing on paper P. The image forming processing is performed when printing image data received via the interface 122 or when printing image data generated by the scanner 15 .

[0059] Next, the image forming process of the image forming apparatus 10 will be described. When receiving a print instruction from a user, the image forming apparatus 10 executes an image forming process for forming an image on the paper P. In the image forming process, Figure 1 As shown, the paper P is drawn out from the paper feed cassette 18 by the pickup roller 18 a and is conveyed between the intermediate transfer belt 21 and the secondary transfer roller 33 by the paper feed roller 35 .

[0060] In parallel with the above-mentioned operation, in the image forming units 20Y, 20M, 20C, and 20K, toner images are formed on the photosensitive drums 22. The toner images formed on the photosensitive drums 22 of the image forming units 20Y, 20M, 20C, and 20K are sequentially transferred to the intermediate transfer belt 21. Thus, a toner image composed of yellow (Y) toner, magenta (M) toner, cyan (C) toner, and black (K) toner is formed on the intermediate transfer belt 21.

[0061] When the paper P conveyed between the intermediate transfer belt 21 and the secondary transfer roller 33 passes through the intermediate transfer belt 21 and the secondary transfer roller 33, the toner image formed on the intermediate transfer belt 21 is transferred onto the paper P. Thus, a toner image composed of yellow (Y), magenta (M), cyan (C), and black (K) toners is formed on the paper P.

[0062] The paper P with the toner image formed thereon passes through the fixing device 50. At this time, the fixing control circuit 150 controls the output of the halogen heater 61 according to the size of the paper P. The paper P is heated by passing through the fixing device 50. As a result, the toner image transferred to the paper P is fixed on the paper P, and an image is formed on the paper P. The paper P with the image formed thereon is discharged to the paper discharge unit 38 by the paper discharge roller 37. In the image forming process, the above-mentioned process is executed a number of times corresponding to the number of copies to be printed.

[0063] As described above, in the fixing device 50 according to the present embodiment, as an example, Figure 5 As shown, the entire lubricant retaining member 90 is impregnated with oil as a first lubricant with low viscosity, and grease as a second lubricant with high viscosity is added to the recessed portion 91 of the lubricant retaining member 90. Thus, the first lubricant with low viscous resistance is applied to the entire area of ​​the inner peripheral surface of the fixing belt 51, and the second lubricant with high viscosity is applied to the annular area A1 of the inner peripheral surface of the fixing belt 51 passing through the recessed portion 91.

[0064] Therefore, the amount of the first lubricant that moves toward the Y-axis end of the fixing belt 51 after being applied to the inner peripheral surface of the fixing belt 51 is reduced. As a result, the first lubricant having a small viscous resistance can be suppressed from flowing out of the fixing belt 51. As a result, the sliding property between the fixing belt 51 and the pressure pad 81 can be maintained for a long time without significantly increasing the viscous resistance. In addition, when a cushioning material such as a sliding sheet 81a is provided between the pressure pad 81 and the fixing belt 51, the sliding property between the cushioning material and the fixing belt 51 can be maintained for a long time.

[0065] Therefore, it is possible to suppress wear of the fixing belt 51 and the pressure pad 81 or the fixing belt 51 and a buffer material such as the sliding sheet 81 a , and maintain the performance of the fixing device 50 for a long period of time.

[0066] When assembling the fixing device, a sufficient amount of lubricant such as silicone oil is applied to the inner circumferential surface of the fixing belt. However, as the fixing belt rotates, the lubricant flows out from the end of the fixing belt and is insufficient. As a result, the sliding property between the fixing belt and the pressure pad decreases. Even if the amount of lubricant applied when assembling the fixing device is increased, the amount of lubricant flowing out when the device is operating and assembled increases, so the effect of increasing the amount of lubricant that helps maintain lubricity is not achieved. In the fixing device involved in this embodiment, the lubricant can be continuously supplied, so the lubricity of the fixing belt can be maintained for a long time.

[0067] In addition, in the fixing device 50 involved in this embodiment, the recessed portion 91 and the slit 92 are alternately provided in the lubricant retaining member 90. By providing the slit 92, the penetration of the second lubricant added to the recessed portion 91 in the Y-axis direction is suppressed. Therefore, in the lubricant retaining member 90, the first lubricant and the second lubricant can be retained in a separated state. Thus, the outflow of the first lubricant can be effectively suppressed by the second lubricant applied to the fixing belt 51. Therefore, the wear caused by the sliding of the fixing belt 51 can be suppressed, and the performance of the fixing device 50 can be maintained for a long time.

[0068] In the fixing device 50 according to the present embodiment, even if the first lubricant flows out, the second lubricant does not flow out and remains on the inner peripheral surface of the fixing belt 51. Therefore, the sliding property of the fixing belt 51 can be maintained for a long period of time.

[0069] The image forming apparatus 10 according to the present embodiment includes the fixing device 50. Therefore, it is possible to continuously form an image with high precision.

[0070] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. Figure 4 As shown in FIG. 1 , the case where the concave portion 91 extending from the outer edge on the +X side to the center of the lubricant retaining member 90 is formed is described. The shape of the concave portion 91 provided in the lubricant retaining member 90 is not limited thereto. Figure 7 As shown in FIG. 1 , the recess 91 may be formed from the contact surface (the surface on the −Z side) of the lubricant retaining member 90 to the center of the lubricant retaining member 90. In this case, Figure 7 A second lubricant with high viscosity is added to the bottom surface of the recessed portion 91 shown in color.

[0071] In this case, the first lubricant with low viscosity resistance is applied to the entire area of ​​the inner peripheral surface of the fixing belt 51, and the second lubricant with high viscosity is applied to the annular area A1 of the inner peripheral surface of the fixing belt 51 passing through the recessed portion 91. Thus, leakage of the first lubricant is suppressed, and as a result, wear caused by sliding of the fixing belt 51 can be suppressed, thereby maintaining the performance of the fixing device 50 for a long time.

[0072] like Figure 7 As shown, when the recessed portion 91 is formed from the contact surface of the lubricant retaining member 90 to the central portion of the lubricant retaining member 90, as shown in FIG. Figure 8 As shown, lubricant retaining members 901 and 902 having the same size in the X-axis direction but different heights may be alternately arranged along the Y-axis. In this case, the boundary between the lubricant retaining members 901 and 902 suppresses the penetration of the lubricant in the Y-axis direction. Therefore, the first lubricant and the second lubricant can be retained in a separated state in the lubricant retaining member 90. Thus, the outflow of the first lubricant can be effectively suppressed by the second lubricant applied to the fixing belt 51.

[0073] In addition, the density of the lubricant retaining member 901 to which the first lubricant with a low viscosity is added can be increased, and the density of the lubricant retaining member 902 to which the second lubricant with a high viscosity is added can be decreased. Thus, two types of lubricants can be retained efficiently.

[0074] In the above embodiment, if Figure 5 As shown in FIG. 1 , seven recessed portions 91 are formed in the lubricant retaining member 90 . However, the present invention is not limited thereto, and the lubricant retaining member 90 may have six or fewer recessed portions 91 or eight or more recessed portions 91 formed therein.

[0075] In addition, considering that the lubricant flows out from both ends of the fixing belt 51, the recesses 91 may be densely arranged at both ends in the Y-axis direction of the lubricant retaining member 90. In addition, the Y-axis dimension of the recesses 91 located at both ends in the Y-axis direction may be larger than that of the other recesses.

[0076] In the above embodiment, the first lubricant is oil and the second lubricant is grease. However, the present invention is not limited thereto, and the first lubricant may be grease instead of oil as long as the viscosity is about 100 cs. Similarly, the second lubricant may be a lubricant other than grease such as oil as long as the viscosity is higher than that of the first lubricant.

[0077] In the above embodiment, the halogen heater 61 is used as a heat source for heating the fixing belt 51. However, the present invention is not limited thereto, and the fixing belt 51 may be heated by electromagnetic induction of a heating coil. Alternatively, the fixing belt 51 may be heated by a ceramic heater or the like.

[0078] For example, in Fig. 9 FIG. 5 shows a fixing device 50A using a ceramic heater 62 as a heat source. Fig. 9 As shown, in the fixing device 50A, the fixing belt 51 is mounted on a pair of driving rollers 501 for rotating the fixing belt 51 and a tension roller 502 for applying tension to the fixing belt 51. The fixing belt 51 rotates in the direction indicated by the arrow A by the driving roller 501 rotating in the direction indicated by the arrow s. The ceramic heater 62 has a substrate composed of, for example, ceramic and a heating portion composed of a resistance layer formed on the substrate. The heating portion is in contact with the inner peripheral surface of the fixing belt 51.

[0079] In the fixing device 50A, the pressure roller 52 is pressed against the heating portion of the ceramic heater 62 in contact with the inner peripheral surface of the fixing belt 51 via the fixing belt 51, thereby forming a gap between the fixing belt 51 and the pressure roller 52. The paper P to which the toner image is transferred passes upward through the gap, and the paper P is heated. As a result, the toner image is fixed on the paper P, and an image is formed on the paper P.

[0080] In the above embodiment, the image forming apparatus 10 is described as a multifunction machine, but the present invention is not limited thereto, and the image forming apparatus 10 may be a laser printer or the like.

[0081] Although several embodiments are described, these embodiments are only presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the purpose of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

1. A fixing device for fixing a toner image formed on a medium to the medium, characterized in that: have: a rotating body supported to be rotatable and heating the medium; A heater for heating the rotating body; A pressing component, disposed inside the rotating body; a pressurizing rotating body which is pressed by the pressing member via the rotating body to form a gap for the medium to pass through; and a lubricant retaining member to which a first lubricant having a first viscosity and a second lubricant having a second viscosity higher than the first viscosity are added, and which abuts against the inner peripheral surface of the rotating body, A concave portion for adding the second lubricant is formed on a contact surface of the lubricant retaining member that contacts the inner peripheral surface of the rotating body. The lubricant retaining member has the recessed portions and the slits along the moving direction alternately arranged in a direction orthogonal to the moving direction of the rotating body.

2. The fixing device according to claim 1, characterized in that: The first lubricant is oil, and the second lubricant is grease.

3. An image forming device, characterized in that: have: a toner image forming unit that forms a toner image; a transfer body for transferring the toner image onto a medium; and The fixing device according to claim 1 or 2 heats the medium to which the toner image is transferred by the transfer body, thereby fixing the toner image to the medium.

Images