Fixing system and image forming apparatus

Abstract

Compared to a configuration that only performs a fixing mode to fix the image on the medium, this configuration suppresses fixing failures on the medium. [Solution] The fixing system comprises a rotating body, an endless fixing belt that contacts the rotating body to form a fixing nip for fixing an image on a medium, a heating member that contacts the inner circumference of the portion of the fixing belt that forms the fixing nip via a lubricant to heat the fixing belt, and a processor, wherein the processor performs a leveling mode in which it rotates the fixing belt while heating the fixing belt to a temperature higher than the fixing temperature when fixing an image on the medium.

Description

Technical Field

[0001] The present disclosure relates to a fixing system and an image forming apparatus.

Background Art

[0002] In Patent Document 1, there is a fixing member that is rotatable with a low heat capacity, a rotating member that rotates while being pressed against the outer surface of the fixing member, a nip forming member that is pressed against the inner surface of the fixing member at a position facing the rotating member to form a nip portion, and a lubricant in a sliding portion between the fixing member and the nip forming member. In an exchangeable fixing device that heats and presses while sandwiching and conveying a recording material by the nip portion to fix an unfixed toner image on the recording material, the fixing device arranges at least one temperature detection element for detecting the temperature of the fixing member or the nip forming member, and in a rotation mode for making the lubricant fit, which is performed at a predetermined time different from the printing operation as the fixing device, it has control means for controlling the temporary stop timing of the fixing device according to the temperature detection result of the temperature detection element. A fixing device is disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure suppresses poor fixing to a medium as compared with a configuration that only executes a fixing mode for fixing an image on the medium.

Means for Solving the Problems

[0005] A fixing system according to a first aspect of the present disclosure comprises a rotating body, an endless fixing belt that contacts the rotating body to form a fixing nip for fixing an image on a medium, a heating member that contacts the inner circumference of the portion of the fixing belt that forms the fixing nip via a lubricant and heats the fixing belt, and a processor, wherein the processor performs a leveling mode in which the heating member heats the fixing belt to a temperature higher than the fixing temperature when fixing an image on the medium while rotating the fixing belt.

[0006] A fixing system according to a second aspect of the present disclosure, in the fixing system according to the first aspect, wherein the processor rotates the fixing belt at a rotational speed faster than the fixing speed when fixing the image during the execution of the leveling mode.

[0007] A fixing system according to a third aspect of the present disclosure, in a fixing system according to a second aspect, wherein the processor maintains the rotation of the fixing belt at a rotational speed faster than the fixing speed when fixing the image for a predetermined time while the leveling mode is being executed.

[0008] A fixing system according to a fourth aspect of the present disclosure, in a fixing system according to a second aspect, wherein in the leveling mode, the processor rotates the fixing belt at a rotational speed faster than the fixing speed when fixing the image, after the temperature of the heating member has reached a temperature higher than the fixing temperature.

[0009] A fixing system according to a fifth aspect of the present disclosure, in a fixing system according to a first aspect, wherein the processor rotates the fixing belt in the opposite direction to the rotation direction of the fixing belt when fixing the image during the execution of the leveling mode.

[0010] A fixing system according to a sixth aspect of the present disclosure, in a fixing system according to a fifth aspect, wherein the processor reverses the rotation of the fixing belt for the entire duration that the fixing belt is operated in the leveling mode.

[0011] The seventh aspect of the present disclosure is a fixing system in the first aspect, wherein the lubricant is a grease mainly composed of a silicone oil as a base oil and one or more thickeners selected from inorganic particles, with a consistency of 250 or less.

[0012] An image forming apparatus according to the eighth aspect of this disclosure comprises an image forming unit for forming an image on a medium, and a fixing system according to any one of the first to sixth aspects for fixing the image formed on the medium. [Effects of the Invention]

[0013] According to the fixing system of the first aspect of this disclosure, fixing failures on the medium are suppressed compared to a configuration that only performs a fixing mode for fixing an image on the medium.

[0014] According to the fixing system of the second aspect of this disclosure, fixing defects are suppressed earlier compared to a configuration in which the fixing belt is rotated at a rotation speed lower than or equal to the fixing speed when fixing the image during the execution of the leveling mode.

[0015] According to the fixing system of the third aspect of this disclosure, the time required for the leveling mode can be shortened compared to a configuration in which the fixing belt is intermittently rotated at a rotational speed faster than the fixing speed during the leveling mode.

[0016] According to the fixing system of the fourth aspect of this disclosure, the load on the fixing belt can be reduced compared to a configuration in which the fixing belt is rotated at a rotational speed faster than the fixing speed before the fixing belt reaches a temperature higher than the fixing temperature.

[0017] According to the fixing system of the fifth aspect of this disclosure, fixing failures are suppressed compared to the case in which the fixing belt rotates only in the rotational direction during fixing while the leveling mode is being executed.

[0018] According to the fixing system of the sixth aspect of this disclosure, fixing failures are suppressed compared to a configuration in which the fixing belt is rotated in the reverse direction as part of the process of rotating the fixing belt during the execution of the leveling mode.

[0019] According to the fixing system of the seventh aspect of the present disclosure, fixing failure is more suppressed as compared with a lubricant having a mixing viscosity exceeding 250.

[0020] According to the image forming apparatus of the eighth aspect of the present disclosure, an image forming apparatus capable of suppressing fixing failure to a medium can be provided as compared with a configuration in which a fixing belt is heated at a temperature lower than the fixing temperature when fixing an image on the medium.

Brief Description of Drawings

[0021] [Figure 1] It is a schematic configuration diagram showing an image forming apparatus according to the present embodiment. [Figure 2] It is a block diagram showing the hardware configuration of a controller according to the present embodiment. [Figure 3] In the fixing system according to the present embodiment, it is a front cross-sectional view showing a state in which a pressure roll is separated from a fixing belt. [Figure 4] In the fixing system according to the present embodiment, it is a front cross-sectional view showing a state in which a pressure roll is pressed against a fixing belt. [Figure 5] It is a flowchart showing modes executable by a controller according to the present embodiment. [Figure 6] It is a flowchart when the controller according to the present embodiment executes a flattening mode.

Modes for Carrying Out the Invention

[0022] <One Embodiment> An example of a fixing system and an image forming apparatus of an embodiment (this embodiment) of the present disclosure will be described while referring to the drawings.

[0023] In the diagram, arrow H indicates the vertical direction of the image forming apparatus, and arrow W indicates the width direction of the image forming apparatus. The vertical direction and the width direction of the image forming apparatus are orthogonal to each other. Furthermore, these directions are defined for the sake of explanation, and the configuration of the image forming apparatus is not limited to these directions. In each direction of the image forming apparatus, the term "image forming apparatus" may be omitted. Also, the +R direction refers to the counterclockwise rotation with the direction perpendicular to the vertical and width directions (depth direction) as the axis. The -R direction refers to the clockwise rotation with the depth direction as the axis.

[0024] (Image forming apparatus) The image forming apparatus 10 forms an image on a sheet member P. The sheet member P is an example of a medium. In the image forming apparatus 10, as shown in Figure 1, the various parts are arranged inside the main body 10a of the apparatus. The image forming apparatus 10 mainly comprises a paper storage unit 12, a main operation unit 14, a transport unit 18, and a controller 70. The image forming apparatus 10 further includes a display unit 40 as an interface for the user to exchange information with the image forming apparatus 10.

[0025] ((Paper storage section)) The paper storage section 12 stores sheet members P. The paper storage section 12 has a first storage section 22, a second storage section 24, a third storage section 26, and a fourth storage section 28. Sheet members P of different sizes are appropriately stored in the first storage section 22, the second storage section 24, the third storage section 26, and the fourth storage section 28. The first storage section 22, the second storage section 24, the third storage section 26, and the fourth storage section 28 are also equipped with a feed roll 32 and a double-feed prevention roll 34, respectively. The feed roll 32 feeds out the stored sheet members P one by one based on instructions from the controller 70 which manages the operation of each part. The double-feed prevention roll 34 transports the sheet members P fed out from the feed roll 32 one by one to the transport path 30 in the image forming apparatus 10.

[0026] ((Main operating part)) The main operating unit 14 outputs image data sent from a user terminal (not shown) or a document reading unit 16 to a sheet member P transported from the paper storage unit 12. The main operating unit 14 includes an image forming unit 60, a transfer unit 68, and a fixing device 100. The main operating unit 14 is an example of an image forming unit.

[0027] The image forming unit 60 forms a toner image. The toner image is an example of an image. The image forming unit 60 has image forming units 64K, 64C, 64M, and 64Y that form toner images of yellow (Y), magenta (M), cyan (C), and black (K). In the following description, unless otherwise specified, the Y, M, C, or K at the end of the symbols may be omitted.

[0028] The image forming unit 64 comprises a photoreceptor drum 62, a charger 42, a developer 44, a cleaning member 46, and an exposure device 66 (66K, 66C, 66M, and 66Y). The charger 42 charges the rotating photoreceptor drum 62, and the exposure device 66 irradiates the charged photoreceptor drum 62 with exposure light to form an electrostatic latent image. Furthermore, the developer 44 develops the electrostatic latent image and visualizes it as a toner image. In other words, the image forming apparatus 10 of this embodiment is an electrophotographic apparatus.

[0029] The transfer unit 68 transfers the toner image to the sheet member P. The transfer unit 68 is located below the image forming unit 60. The transfer unit 68 includes a transfer belt 48, a primary transfer roll 50, a secondary transfer roll 52, an auxiliary roll 54, and a roll 56.

[0030] The transfer belt 48 is formed in an endless manner and, when viewed from the front side in the depth direction, has a triangular shape with its vertex pointing downwards, and contacts the image forming unit 60 from below in the vertical direction. The depth direction is perpendicular to the vertical direction and the width direction.

[0031] The primary transfer rolls 50 (50K, 50C, 50M, and 50Y) are cylindrical in shape and extend in the depth direction. They are positioned in conjunction with the photoreceptor drum 62 and sandwich the transfer belt 48 between them, transferring the toner image from the photoreceptor drum 62 to the transfer belt 48.

[0032] The secondary transfer roll 52 is cylindrical in shape and extends in the depth direction, positioned below the primary transfer roll 50, and transfers the toner image on the transfer belt 48 to the sheet member P at the transfer position T.

[0033] The auxiliary roll 54 is cylindrical in shape and extends in the depth direction. It is positioned inside the transfer belt 48 and on the opposite side of the secondary transfer roll 52, with the transfer belt 48 in between.

[0034] Multiple rolls 56 are arranged inside the transfer belt 48, and the transfer belt 48 is wrapped around them. One of the rolls 56 functions as a drive roll that causes the transfer belt 48 to rotate in the direction of arrow C in the figure.

[0035] The fixing device 100 is positioned downstream of the transfer position T and fixes the toner image transferred onto the sheet member P to the sheet member P. Details of the fixing device 100 will be described later.

[0036] ((Transportation section)) The conveying unit 18 receives sheet members P that are conveyed from the double-feed prevention roll 34 or inserted from outside the main body of the device 10a and conveys them one by one. The conveying unit 18 has a conveying path 30, a conveying roll 36, and a conveying device 38.

[0037] The transport path 30 is the path that determines the transport direction of the sheet member P (hereinafter simply referred to as "transport direction CV").

[0038] The upstream portion of the transport path 30 extends from bottom to top on one side in the width direction. A manual feed path 33 is connected to the upper end of the upstream portion of the transport path 30.

[0039] The downstream portion of the transport path 30 extends from one side in the width direction to the other, and is connected to a discharge section 80 that discharges the sheet member P to the outside of the device body 10a. A double-sided transport path 31 is connected to the downstream end of the transport path 30, where the sheet member P is transported and inverted in order to form an image on the back surface of the sheet member P. The double-sided transport path 31 is equipped with a switchback path 31a, and the sheet member P sent out from the switchback path 31a is inverted front and back and sent to the upper end of the upstream portion of the transport path 30 in the transport direction CV.

[0040] The conveying rolls 36 are cylindrical in shape and extend in the depth direction, and multiple rolls are arranged along the conveying path 30. The conveying rolls 36 are arranged in pairs on the main body 10a of the device so as to sandwich the conveying path 30.

[0041] The transport device 38 is positioned upstream of the transfer position T in the transport direction CV, and temporarily stops the sheet member P, then sends the sheet member P to the secondary transfer position at a predetermined timing.

[0042] ((controller)) The controller 70 is a computer that controls various parts of the image forming apparatus 10.

[0043] As shown in Figure 2, the controller 70 comprises a CPU (Central Processing Unit) 72A, ROM (Read Only Memory) 72B, RAM (Random Access Memory) 72C, storage 72D, input / output unit 74, and network interface (Network I / F) 76. Each component is connected to the others via a bus 72E so that they can communicate with each other.

[0044] The CPU 72A is a central processing unit that executes various programs and controls various components. Specifically, the CPU 72A reads programs from ROM 72B or storage 72D and executes them using RAM 72C as the working area. The CPU 72A is an example of a processor that constitutes a fuser system. The CPU 72A controls the above components and performs various calculations according to the programs recorded in ROM 72B or storage.

[0045] ROM72B stores various programs and data. RAM72C temporarily stores programs or data as a working area. Storage72D consists of an HDD (Hard Disk Drive) or SSD (Solid State Drive) and stores various programs, including the operating system, and various data.

[0046] The input / output unit 74 receives signals between the various components of the image forming apparatus 10 in order to enable the image forming apparatus 10 to perform its functions. For example, the input / output unit 74 receives signals between the paper storage unit 12, the main operation unit 14, and the transport unit 18.

[0047] Network I / F76 is an interface for communicating with other devices such as databases and servers (not shown in the diagram), and standards such as Ethernet®, FDDI, and Wi-Fi® are used.

[0048] <Details of the fixing device> As shown in Figures 3 and 4, the fixing device 100 includes a pressure roll 120 and a heating unit 140. In the fixing device 100, the pressure roll 120 and the heating unit 140 fix the toner image to the sheet member P. Specifically, the fixing device 100 heats and pressurizes the sheet member P transported from the image forming unit 60, thereby fixing the toner image transferred to the sheet member P in the image forming unit 60 to the sheet member P. The fixing device 100, together with the CPU 72A of the controller 70, constitutes a fixing system.

[0049] [Pressure Roll] The pressure roll 120 is a roll-shaped member oriented in the depth direction. The pressure roll 120 is positioned below the transport path 30. The pressure roll 120 is rotatably supported relative to the device body 10a and is rotationally driven in the +R and -R directions by a drive unit (not shown). The pressure roll 120 is an example of a rotating body. The pressure roll 120 is also capable of moving toward and away from the transport path 30 by a separation mechanism (not shown). The pressure roll 120 is configured to apply pressure to the sheet member P.

[0050] The pressure roll 120 has a multilayer structure comprising a core metal 124, an elastic layer 122, and a release layer (not shown). The core metal 124 is a thin-walled cylindrical shape made of steel and is supported by the main body 10a of the apparatus. The elastic layer 122 is a layer containing silicone rubber or the like that is coated on the surface of the core metal 124. The release layer (not shown) is a layer of fluororesin that is coated on the surface of the elastic layer 122.

[0051] [Heating section] The heating unit 140 is a structure that follows the depth direction. The heating unit 140 is positioned above the transport path 30. The heating unit 140 is configured to melt the toner on the sheet member P. The heating unit 140 includes a fixing belt 142, a heater 144, a pad 146, and a support member 148.

[0052] The fixing belt 142 is an endless belt with its axial direction in the depth direction. The fixing belt 142 has a thin-walled cylindrical base material made of a synthetic resin such as polyimide resin or polyamide-imide resin, and a release layer containing fluororesin is provided on its outer surface as needed. The fixing belt 142 is rotatably supported with respect to the main body 10a of the apparatus. The fixing belt 142 follows the rotation of the pressure roll 120 as the pressure roll 120 is pressed against it, moving in the -R direction and the +R direction. For example, the fixing belt 142 rotates in the +R direction as the pressure roll 120 rotates in the -R direction as the pressure roll 120 is pressed against it.

[0053] The heater 144 is a planar heating element positioned along the depth direction and inside the fixing belt 142. The heater 144 contacts the inner circumferential surface of the fixing belt 142 when the pressure roll 120 is pressed against the fixing belt 142. The heater 144 is temperature-adjustable based on instructions from the controller 70. The heater 144 heats the fixing belt 142 via grease G.

[0054] Here, grease G is a lubricant that reduces the sliding resistance between the fixing belt 142 and the heater 144 when sandwiched between them. Grease G has a lower consistency than fluorine grease. For example, the mixed consistency of grease G is 250 or less as specified in JIS K 2220. Furthermore, the viscosity of grease G at 200°C, as measured by a rheometer, is 50 to 1500 Pa·s. Preferably, the viscosity of grease G is 80 to 1000 Pa·s. More preferably, the viscosity of grease G is 100 to 500 Pa·s. The weight loss rate of grease G when heated and stored at 230°C for 336 hours is 0 to 20 wt%. Preferably, the weight loss rate of grease G is 0 to 15 wt%. More preferably, the weight loss rate of grease G is 0 to 10 wt%.

[0055] Grease G is composed of a base oil combined with a thickener. The base oil of Grease G is a silicone oil, preferably dimethyl silicone oil, methylphenyl silicone oil, or diphenyl silicone oil, and may have partial side chains introduced. The weight-average molecular weight Mw of the silicone oil is 10,000 to 100,000. Furthermore, the weight-average molecular weight Mw is preferably 10,000 to 60,000. And more preferably, the weight-average molecular weight Mw is 15,000 to 40,000.

[0056] Furthermore, in Grease G, one or more inorganic materials such as melamine cyanurate, boron nitride, carbon black, silica, graphite, molybdenum disulfide, zinc stearate, and tungsten disulfide are selected as components of the thickener. The average particle size (D50v) of the thickener is 0.01 to 15 μm. Preferably, the average particle size is 0.1 to 10 μm. More preferably, the average particle size is 0.1 to 5 μm.

[0057] The weight ratio of base oil in the components of grease G is 40 to 95 wt%. Preferably, the weight ratio is 50 to 85 wt%. More preferably, the weight ratio is 50 to 75 wt%.

[0058] The viscosity of grease G is measured by the following method: A grease sample is placed between parallel plates with a diameter of 40 mm, and the viscosity is measured using a dynamic viscoelasticity measuring device (rheometer ARES-G2, manufactured by T.A. Instruments Inc.) with a gap of 1 mm and an angular velocity of 0.1 rad / s, while the temperature is increased from 40°C to 200°C at a rate of 6°C / min.

[0059] The weight loss rate of grease G is calculated by taking a 5g sample of grease in an aluminum cup and heating it in an oven at 230°C for 336 hours, then comparing the weight before and after heating.

[0060] The average particle size of the thickener is measured by the following method: A 2g sample of grease is placed on filter paper, and 30g of THF (tetrahydrofuran) is added and filtered by suction to separate the base oil and the thickener. The separated thickener is dispersed in water, and the particle size distribution is measured using a particle size analyzer (LS13320, Beckman Coulter).

[0061] The pad 146 is a block-shaped member positioned along the depth direction and inside the fixing belt 142. The pad 146 supports the heater 144 from the outside, covering it from the inside of the fixing belt 142. In other words, the pad 146 supports the heater 144 at the upstream side of the downstream end 146A and the downstream side of the upstream end 146B in the fixing direction when the toner image is fixed onto the sheet member P. The pad 146 is positioned such that the downstream end 146A and the upstream end 146B are in contact with the inner circumferential surface of the fixing belt 142 when the pressure roll 120 is pressed against the fixing belt 142. The pad 146 is supported by the main body 10a of the device. The pad 146 directs the outer circumferential surface of the fixing belt 142 toward the outer circumferential surface of the pressure roll 120. The pad 146 further has a recess 146C. The recess 146C is a recessed portion formed on the surface opposite to the support surface of the heater 144.

[0062] The support member 148 is positioned along the depth direction and inside the fixing belt 142, and has a frame shape that is an inverted U when viewed from the depth direction. The support member 148 is supported by the main body 10a of the device. The support member 148 supports the pad 146 via the recess 146C. The support member 148 receives the pressing force of the pressure roll 120 via the heater 144 and the pad 146 when the fixing belt 142 is pressed against the pressure roll 120.

[0063] [Fixed nip] The fixing nip N will now be explained. The fixing nip N is formed in the portion where the fixing belt 142 contacts the pressure roll 120 to fix the toner image on the sheet member P. In the fixing nip N, the heater 144 heats the fixing belt 142 via grease G. In other words, the heater 144 contacts the inner circumference of the portion of the fixing belt 142 that forms the fixing nip N via grease G. Also, in the fixing nip N, the heated fixing belt 142 melts the toner on the sheet member P. Then, in the fixing nip N, the pressure roll 120 presses against the fixing belt 142, sandwiching the sheet member P between the two. As a result, the toner image is fixed on the sheet member P by the fixing nip N.

[0064] 〔mode〕 The two modes that the controller 70 operates in are described below. The two modes consist of a fixing mode and a leveling mode.

[0065] [Fusing Mode] The fixing mode is the mode that the image forming apparatus 10 executes when forming an image. In the fixing mode, the toner image is fixed to the sheet member P based on the fixing temperature and fixing speed.

[0066] The fixing temperature is a predetermined temperature at which the toner image is fixed to the sheet member P by the fixing nip. In this embodiment, the fixing temperature is the temperature commanded from the controller 70 to the heater 144. For example, the fixing temperature is 180°C.

[0067] The fixing speed is defined as the rotational speed at which the toner image is fixed to the sheet material P. The fixing speed is equivalent to the transport speed of the transport unit 18. In this embodiment, the fixing speed is defined as the command speed from the controller 70 to the pressure roll 120. In fixing mode, the pressure roll 120 rotates in the -R direction. Rotation of the pressure roll 120 in the -R direction is an example of a fixing direction.

[0068] [Leveling Mode] The leveling mode is a mode performed between image formation operations by the image forming apparatus 10. The leveling mode is performed with the aim of leveling out the unevenness (unevenness) in the thickness direction of the grease G in the fixing nip N. In the leveling mode, leveling temperature, first speed, and second speed are taken into consideration.

[0069] The leveling temperature is set to a temperature higher than the fixing temperature. In this embodiment, the leveling temperature is the command temperature from the controller 70 to the heater 144, which is set based on the temperature characteristics of the grease G. For example, the leveling temperature is set to a temperature 20°C higher than the fixing temperature. Note that there may be a range for the leveling temperature.

[0070] The first speed is set to a speed slower than the fixing speed. For example, the first speed may be 50% to 80% of the fixing speed. In this embodiment, the first speed is the command speed from the controller 70 to the pressure roll 120. The first speed may have a range.

[0071] The second speed is set to a speed faster than the fixing speed. For example, the second speed may be 120% to 150% of the fixing speed. In this embodiment, the first speed is the command speed from the controller 70 to the pressure roll 120. The second speed may have a range. In leveling mode, the fixing belt 142 is rotated at either the first speed or the second speed.

[0072] In leveling mode, the thickness of the grease G is leveled by maintaining the first speed for a first time. The first time is an example of a predetermined time. For example, the first time may be 30 seconds.

[0073] 〔flowchart〕 [Mode Determination] The mode switching in controller 70 will be explained with reference to Figure 5.

[0074] In step S10, the CPU 72A of the controller 70 determines whether or not the fixing mode can be maintained.

[0075] For example, in the following cases (i) to (iii), the CPU72A is not allowed to maintain the fixing mode and enters the leveling mode. (i) When the image forming apparatus 10 has formed a predetermined number of images (ii) When a predetermined time has elapsed after image formation by the image forming apparatus 10 (iii) When the user (not shown) of the image forming apparatus 10 gives instructions

[0076] If the judgment result is "Y" indicating a positive result, CPU72A proceeds to step S20. In step S20, CPU72A executes the fixing mode. Then, CPU72A terminates the flow.

[0077] On the other hand, if the judgment result is "N" indicating negation, CPU72A proceeds to step S30. In step S30, CPU72A executes the averaging mode. Then, CPU72A returns the flow to the beginning.

[0078] The mode is then switched.

[0079] [Execute the leveling mode] Next, the execution of the leveling mode in the controller 70 will be explained with reference to Figure 6. In the leveling mode of this embodiment, the controller 70 heats the fixing belt 142 with the heater 144 at a temperature higher than the fixing temperature, and rotates the pressure roll 120 in the -R direction, thereby causing the fixing belt 142 to rotate in the +R direction.

[0080] In step S32, the CPU 72A of the controller 70 switches the pressure roll 120 from the state shown in Figure 3 to the state shown in Figure 4 relative to the contact / separation mechanism, thereby pressing the pressure roll 120 against the fixing belt 142. Then, the CPU 72A proceeds to step S34.

[0081] In step S34, the CPU 72A rotates the pressure roll 120 in the -R direction at a first speed relative to the drive unit. Then, the CPU 72A proceeds to step S36.

[0082] In step S36, CPU 72A causes heater 144 to heat the fixing belt 142. Then, CPU 72A proceeds to step S38.

[0083] In step S38, CPU 72A determines whether the temperature of heater 144 is above the average temperature.

[0084] If the result of the judgment is "Y", CPU72A proceeds to step S40.

[0085] On the other hand, if the judgment result is "N", the CPU 72A proceeds to step S36. The CPU 72A then heats the heater 144 until its temperature reaches or exceeds the average temperature.

[0086] In step S40, CPU 72A rotates the pressure roll 120 in the -R direction at a second speed relative to the drive unit. In other words, in this embodiment, after the heater 144 reaches the leveling temperature, CPU 72A rotates the fixing belt 142 in the +R direction by rotating the pressure roll 120 in the -R direction at a second speed. Then, CPU 72A proceeds to step S42.

[0087] In step S42, CPU 72A determines whether 1 time has elapsed since the pressure roll 120 was rotated in the -R direction at the second speed.

[0088] If the result of the judgment is "Y", CPU72A proceeds to step S44.

[0089] On the other hand, if the judgment result is "N", the CPU 72A proceeds to step S40. The CPU 72A then continues to rotate the pressure roll 120 in the -R direction at the second speed until the first time has elapsed.

[0090] In step S44, the CPU 72A instructs the drive unit to change the rotational speed of the pressure roll 120 from the second speed to the first speed. Then, the CPU 72A proceeds to step S46.

[0091] In step S46, the CPU 72A separates the pressure roll 120 from the fixing belt 142 with respect to the contact / separation mechanism. Then, the CPU 72A terminates the flow.

[0092] Based on the above, the leveling mode is executed.

[0093] <Effects and Effects> Next, the effects and advantages of this embodiment will be explained.

[0094] The fixing system of this embodiment includes a pressure roll 120, an endless fixing belt 142 that contacts the pressure roll 120 to form a fixing nip N for fixing a toner image on a sheet member P, a heater 144 that contacts the inner circumference of the portion of the fixing belt 142 that forms the fixing nip N via grease G to heat the fixing belt 142, and a CPU 72A of the controller 70. The CPU 72A performs a leveling mode in which it rotates the fixing belt 142 while heating the fixing belt 142 with the heater 144 at a leveling temperature higher than the fixing temperature when fixing the toner image on the sheet member P.

[0095] With this configuration, compared to a configuration that only performs a fixing mode to fix the toner image on the sheet member P, fixing defects on the sheet member P are suppressed.

[0096] In the fixing system of this embodiment, the CPU 72A rotates the fixing belt 142 at a second speed that is faster than the fixing speed when fixing the toner image, while the leveling mode is being executed.

[0097] With this configuration, compared to a configuration in which the fixing belt is rotated at a rotation speed lower than the fixing speed when fixing the toner image during the leveling mode, fixing defects are suppressed earlier.

[0098] In the fixing system of this embodiment, the CPU 72A maintains the rotation of the fixing belt 142 at a second speed faster than the fixing speed when fixing the toner image for a first time while the leveling mode is being executed.

[0099] This configuration allows for a reduction in the time required for the leveling mode compared to a configuration in which the fixing belt is intermittently rotated at a rotational speed faster than the fixing speed during the leveling mode.

[0100] In the fixing system of this embodiment, during the execution of the leveling mode, the CPU 72A rotates the fixing belt 142 at a second speed that is faster than the fixing speed when fixing the toner image, after the temperature of the heater 144 has reached the leveling temperature.

[0101] This configuration reduces the load on the fixing belt 142 compared to a configuration in which the fixing belt is rotated at a second speed before the fixing belt reaches the leveling temperature.

[0102] In the fixing system of this embodiment, grease G is a grease whose main components are silicone oil as a base oil and one or more thickeners selected from melamine cyanurate, boron nitride, carbon black, silica, graphite, molybdenum disulfide, zinc stearate, tungsten disulfide, and other inorganic particles, and whose mixed consistency is 250 or less.

[0103] With this configuration, poor adhesion is more effectively suppressed compared to lubricants with a consistency score exceeding 250.

[0104] The image forming apparatus 10 of this embodiment includes a main operating unit 14 for forming a toner image on a sheet member P, and a fixing system for fixing the toner image formed on the sheet member P.

[0105] This image forming apparatus provides an image forming apparatus 10 that suppresses poor fixing to the sheet member P, compared to a configuration in which the fixing belt is heated at a temperature below the fixing temperature when fixing the toner image on the sheet member P.

[0106] <Variation> Although this disclosure has described in detail certain embodiments, it will be apparent to those skilled in the art that this disclosure is not limited to such embodiments and can take various other embodiments within the scope of this disclosure.

[0107] In the above embodiment, an image forming apparatus 10 having the apparatus layout shown in Figure 1 was used for the explanation, but it is not limited thereto. For example, this disclosure is also applicable to image forming apparatuses having a different apparatus layout from that of the image forming apparatus 10. Furthermore, in the above embodiment, the main operating unit 14 was described using a tandem color type, but it is not limited thereto. The main operating unit may be rotary or monochrome. Also, the main operating unit is not limited to an indirect transfer method, but may be a direct transfer method.

[0108] In the leveling mode of the above embodiment, the CPU 72A rotates the pressure roll 120 in the -R direction, thereby causing the fixing belt 142 to rotate in the +R direction, but this is not limited to this. For example, in any of steps S34, S40, or S44 shown in Figure 6, the CPU 72A may rotate the pressure roll 120 in the +R direction, thereby causing the fixing belt 142 to rotate in the -R direction. Rotation of the fixing belt 142 in the -R direction is an example of reverse rotation. According to this modified example, fixing failures are suppressed compared to the case where the fixing belt rotates only in the rotation direction during fixing while the leveling mode is being executed.

[0109] Furthermore, in the above modified example, the CPU 72A may rotate the fixing belt 142 in the -R direction for the entire duration during which the fixing belt 142 is rotated while the leveling mode is being executed. Rotation is just one example of operation. In other words, the CPU 72A may rotate the fixing belt 142 in the -R direction in all steps S34, S40, and S44 during the execution of the leveling mode. In this case, fixing failures are suppressed compared to a configuration in which the fixing belt is rotated in the reverse direction for part of the steps during which the fixing belt is rotated while the leveling mode is being executed.

[0110] In the above embodiment, the CPU 72A rotates the fixing belt 142 at a second speed faster than the fixing speed when fixing the toner image during the execution of the leveling mode, but it is not limited to this. For example, in the leveling mode, the CPU 72A may rotate the fixing belt 142 at a speed equal to the fixing speed or at a first speed.

[0111] In the above embodiment, the CPU 72A maintains the rotation of the fixing belt 142 at a second speed for a first time while the leveling mode is being executed, but it is not limited to this. For example, the CPU 72A may maintain the rotation of the fixing belt 142 at a speed lower than or equal to the fixing speed for a first time while the leveling mode is being executed.

[0112] In the above embodiment, the CPU 72A rotates the fuser belt 142 to a target speed that is faster than the fixing speed used when fixing the toner image, after the heater 144 has reached the leveling temperature during the execution of the leveling mode, but it is not limited to this. For example, the CPU 72A may start increasing the rotation speed of the fuser belt 142 from the fixing speed towards the second speed before the heater 144 reaches the leveling temperature during the execution of the leveling mode.

[0113] In the above embodiment, the fixing belt 142 is described as following the rotation of the pressure roll 120 while the pressure roll 120 is pressed against it, but it is not limited to this. For example, the pressure roll 120 may be pressed against the fixing belt 142 and follow the rotation of the fixing belt 142 in the direction of -R and +R.

[0114] In the above embodiment, the leveling temperature is the temperature commanded from the controller 70 to the heater 144, but it is not limited to this. For example, the leveling temperature may be determined by actually measuring the temperature of the inner surface of the fixing belt 142 using a non-contact temperature sensor (not shown).

[0115] In the above embodiment, the CPU 72A instructs the drive unit to change the rotational speed of the pressure roll 120 from the second speed to the first speed in step S44, but it is not limited to this. For example, the CPU 72A may instruct the drive unit to change the rotational speed of the pressure roll 120 from the second speed to zero in step S44. In other words, the CPU 72A may stop the rotation of the pressure roll 120 in step S44.

[0116] In the above embodiment, the flow order is not limited to that shown in Figure 6. For example, steps S36 and S34 may be swapped. In other words, the CPU 72A may rotate the pressure roll 120 after heating the fixing belt 142 with the heater 144.

[0117] In this embodiment, each process is executed on any computer. Furthermore, any computer may execute these processes using a processor as hardware, a program as software, or a combination thereof. In that case, the processor is configured to work in cooperation with the program to execute the various processes in this embodiment, and can function as a unit or means in this embodiment. Also, the execution order of the processes by the processor is not limited to the order described and may be changed as appropriate. Any computer may be a general-purpose computer, a computer designed for a specific purpose, a workstation, or any other system capable of executing each process.

[0118] A processor may consist of one or more hardware components, and the type of hardware is not limited. For example, a processor may consist of a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a programmable logic device such as an FPGA (Field Programmable Gate Array), a dedicated circuit for executing a specific process such as an ASIC (Application Specific Integrated Circuit), a GPU (Graphic Processing Unit), or an NPU (Neural Processing Unit). Furthermore, the type of hardware may be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a processor, these components may reside in physically separate devices or in the same device. Also, in any embodiment, the order of each process performed by the processor is not limited to the order described above and may be changed as appropriate. Hardware is composed of electrical circuits (circuitry) that combine circuit elements such as semiconductor elements.

[0119] Furthermore, the program may be firmware or software such as microcode. Alternatively, the program may be, for example, a group of program modules, each function of which may be implemented by a processor configured to perform its respective function. The program may be program code or multiple code segments stored on one or more non-temporary computer-readable media (e.g., storage media or other storage devices). The program may be divided and stored on multiple non-temporary computer-readable media located on physically separate devices. The program code or code segments may represent any combination of procedures, functions, subprograms, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. The program code or code segments may be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents. The program of this application may also be provided as a program product.

[0120] (Note) (((1))) A rotating body and An endless fixing belt that forms a fixing nip that contacts the rotating body to fix an image on the medium, A heating member that contacts the inner circumference of the portion of the fixing belt that forms the fixing nip via a lubricant and heats the fixing belt, Equipped with a processor, The aforementioned processor, A leveling mode is performed in which the fixing belt is rotated while the fixing belt is heated by the heating element at a temperature higher than the fixing temperature when fixing the image on the medium. Fixing system. (((2))) The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated at a rotational speed faster than the fixing speed used when fixing the image. The fixing system described in (((1))). (((3))) The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated at a rotation speed faster than the fixing speed used when fixing the image for a predetermined period of time. The fixing system described in (((2))). (((4))) The aforementioned processor, During the execution of the leveling mode, after the temperature of the heating element reaches a temperature higher than the fixing temperature, the fixing belt is rotated at a rotation speed faster than the fixing speed used when fixing the image. The fixing system described in (((2))) or (((3))). (((5))) The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated in the opposite direction to the rotation direction of the fixing belt when fixing the image. A fixing system as described in any one of the items (((1))) to (((4))). (((6))) The aforementioned processor, During the entire period in which the fixing belt is operated in the leveling mode, the fixing belt is rotated in the reverse direction. The fixing system described in (((5))). (((7))) The fixing system according to any one of the items (((1))) to (((6))), wherein the lubricant is a grease mainly composed of a silicone oil as a base oil and one or more thickeners selected from inorganic particles, and having a mixed consistency of 250 or less. (((8))) An image forming unit that forms an image on a medium, A fixing system according to any one of the items (((1))) to (((7))) for fixing an image formed on the medium, An image forming apparatus comprising:

[0121] According to the fixing system of (((1))), fixing failures on the medium are suppressed compared to a configuration that only performs a fixing mode to fix the image on the medium. According to the fixing system of (((2))), fixing failures are suppressed earlier compared to a configuration in which the fixing belt is rotated at a rotation speed lower than the fixing speed when fixing the image during the execution of the leveling mode. According to the fixing system of (((3))), the time required for the leveling mode can be shortened compared to a configuration in which the fixing belt is intermittently rotated at a rotational speed faster than the fixing speed during the leveling mode. According to the fixing system of (((4))), the load on the fixing belt can be reduced compared to a configuration in which the fixing belt is rotated at a rotational speed faster than the fixing speed before the fixing belt reaches a temperature higher than the fixing temperature. According to the fixing system of (((5))), fixing failures are suppressed compared to the case where the fixing belt rotates only in the direction of rotation during fixing while the leveling mode is being executed. According to the fixing system of (((6))), fixing failures are suppressed compared to a configuration in which the fixing belt is rotated in the reverse direction during part of the process of rotating the fixing belt while the leveling mode is being executed. According to the fixing system of (((7))), poor fixing is more effectively suppressed compared to lubricants with a consistency of over 250. The image forming apparatus of (((8))) provides an image forming apparatus that suppresses poor fixing to the medium compared to a configuration in which the fixing belt is heated at a temperature below the fixing temperature when fixing the image on the medium. [Explanation of Symbols]

[0122] 10 Image forming apparatus 10a Main unit of the device 12 Paper storage section 14. Main operating unit (an example of an image forming unit) 16. Manuscript Reading Unit 18 Conveying section 22. First containment unit 24 Second Detention Unit 26 Third Detention Unit 28. Fourth Detention Unit 30. Transport Route 31 Double-sided transport route 31a Switchback road 32 Dispensing Rolls 33 Hand-pointed path 34 Double-feed prevention roll 36 Conveyor Rolls 38 Conveying device 40 Display section 42 Charger 44 Developer 46 Cleaning parts 48 Transfer Belt 50 Primary Transfer Rolls 52 Secondary transfer roll 54 Auxiliary Rolls 56 rolls 60 Image forming unit 62 Photoconductor Drum 64 Image forming unit 66 Exposure equipment 68 Transfer Unit 70 Controllers 72A CPU (an example of a processor) 72D Storage 72E Bus 74 Input / output section 76 Network Interface 80 Discharge section 100 Fixing device 120 Pressure Roll (Example of a Rotating Body) 122 Elastic layer 124 Mandrel 140 Heating section 142 Fixing belt 144 Heater (an example of a heating element) 146 pads 146A Tip 146B Rear end 146C recess 148 Support member CV transport direction G Grease N Fixing Nip P Sheet Material T transcription position

Claims

1. A rotating body and An endless fixing belt that forms a fixing nip that contacts the rotating body to fix an image on the medium, A heating member that contacts the inner circumference of the portion of the fixing belt that forms the fixing nip via a lubricant and heats the fixing belt, Equipped with a processor, The aforementioned processor, A leveling mode is performed in which the fixing belt is rotated while the fixing belt is heated by the heating element at a temperature higher than the fixing temperature when fixing the image on the medium. Fixing system.

2. The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated at a rotational speed faster than the fixing speed used when fixing the image. The fixing system according to claim 1.

3. The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated at a rotation speed faster than the fixing speed used when fixing the image for a predetermined period of time. The fixing system according to claim 2.

4. The aforementioned processor, During the execution of the leveling mode, after the temperature of the heating element reaches a temperature higher than the fixing temperature, the fixing belt is rotated at a rotation speed faster than the fixing speed used when fixing the image. The fixing system according to claim 2.

5. The aforementioned processor, During the execution of the leveling mode, the fixing belt is rotated in the opposite direction to the rotation direction of the fixing belt when fixing the image. The fixing system according to claim 1.

6. The aforementioned processor, During the entire period in which the fixing belt is operated in the leveling mode, the fixing belt is rotated in the reverse direction. The fixing system according to claim 5.

7. The fixing system according to claim 1, wherein the lubricant is a grease mainly composed of a silicone oil as a base oil and one or more thickeners selected from inorganic particles, and having a mixed consistency of 250 or less.

8. An image forming unit that forms an image on a medium, A fixing system according to any one of claims 1 to 7 for fixing an image formed on the medium, An image forming apparatus comprising:

Images