Fixing system and image forming system

Abstract

To provide a fixing system capable of reducing the possibility that a system down occurs in comparison with a configuration that detects rotational torque of a heating member and reduces a rotational speed of the heating member when the detected rotational torque exceeds a prescribed threshold value, and to provide an image forming system provided with the same.SOLUTION: A fixing system comprises: a heating member for fixing a toner image on a recording medium by rotating and conveying the recording medium while holding it between itself and a pressure member; and a processor. The processor controls the rotational speed of the pressure member or the heating member in a first mode and in a second mode in which rotational torque is higher than in the first mode. When rotational torque in the second mode predicted from a detection result of rotational torque in the first mode is higher than a prescribed threshold value, the processor controls the pressure member or the heating member in advance so that the threshold value is not exceeded.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Image forming apparatuses have been known for some time that detect the amount of current (torque) required by a fixing drive means and change the fixing processing speed depending on the detection results, thereby making it possible to continue use under conditions where the drive load (torque) is unlikely to increase even if an increase in the drive load (torque increase) occurs, thereby making it possible to avoid immediate device shutdown (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-138427 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a fixing system that can reduce the possibility of a system crash compared to a configuration in which the rotational torque of a heating member is detected and, when the detected rotational torque exceeds a predetermined threshold, the rotational speed of the heating member is reduced, and an image forming system equipped with the same. [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, a fixing system of a first aspect of the present invention comprises a heating member that fixes a toner image onto a recording medium while rotating and transporting the recording medium between a pressure member and the heating member, and a processor, wherein the processor controls the rotational speed of the pressure member or the heating member between a first mode and a second mode in which the rotational torque is higher than that in the first mode, and when the rotational torque in the second mode predicted from the detection result of the rotational torque in the first mode is higher than a predetermined threshold value, the processor controls the pressure member or the heating member in advance so that the rotational torque does not exceed the predetermined threshold value.

[0006] Further, a second aspect of the fixing system according to the present invention is the fixing system of the first aspect, wherein when the predicted rotational torque in the second mode is lower than the threshold value and it is determined from past trends in the rotational torque that the rotational torque in the second mode will exceed the threshold value, the processor controls the pressure member or the heating member in advance so that the rotational torque does not exceed the threshold value.

[0007] Furthermore, a fixing system of a third aspect of the present invention is the fixing system of the second aspect, wherein the processor controls the pressure member or the heating member in the second mode when the predicted rotational torque in the second mode is higher than the threshold value and when it is determined from past trends in rotational torque that the rotational torque in the second mode will not exceed the threshold value.

[0008] Furthermore, a fixing system of a fourth aspect according to the present invention is the fixing system of the first aspect, wherein the processor reduces the rotational speed of the pressure member or the heating member in advance so as not to exceed the threshold.

[0009] Furthermore, a fixing system of a fifth aspect of the present invention is the fixing system of the fourth aspect, wherein when the predicted rotational torque in the second mode is continuously higher than the threshold value, the processor does not detect the rotational torque in the first mode, or sets the rotational speed of the pressure member or the heating member during rotational transport of the recording medium to the first mode regardless of whether or not the rotational torque is detected.

[0010] A fixing system according to a sixth aspect of the present invention is the fixing system according to the first aspect, wherein the processor increases the temperature of the heating member so that the temperature does not exceed the threshold value.

[0011] In addition, a seventh aspect of the image forming system according to the present invention includes a transfer unit that transfers a toner image to a recording medium, and a fixing system of any one of the first to sixth aspects that fixes the toner image transferred by the transfer unit to the recording medium. Effect of the Invention

[0012] According to the first aspect of the invention, the possibility of a system failure can be reduced compared to a configuration in which the rotational torque of the heating member is detected and, if the detected rotational torque exceeds a predetermined threshold, the rotational speed of the heating member is reduced.

[0013] According to the second aspect of the invention, when the predicted rotational torque is lower than the threshold value, the possibility of a system failure occurring can be reduced compared to a case in which the rotational torque of the heating member is always maintained.

[0014] According to the third aspect of the invention, the processing speed during printing is not reduced.

[0015] According to the fourth aspect of the invention, the rotational torque of the heating member can be easily reduced compared to the case where a separate braking torque is applied.

[0016] According to the fifth aspect of the invention, even if the predicted rotational torque is continuously higher than the threshold value, the possibility of a system failure can be reduced compared to when the predicted rotational torque is controlled so as not to exceed the threshold value.

[0017] According to the sixth aspect of the invention, the rotational torque of the heating member can be easily reduced compared to the case where a separate braking torque is applied.

[0018] According to the seventh aspect of the invention, it is possible to obtain an image forming system in which the possibility of a system failure is reduced compared to a configuration in which the rotational torque of the heating member is detected and, if the detected rotational torque exceeds a predetermined threshold value, the rotational speed of the heating member is reduced. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic diagram illustrating a schematic configuration of an image forming system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram showing a fixing device constituting the fixing system according to the present embodiment; [Diagram 3] 1 is a graph showing the relationship between the rotation speed and the rotation torque of a heating member (Stribeck curve). [Figure 4] 1 is a graph showing the relationship between the number of prints and the rotation torque. [Diagram 5] 5 is a flowchart showing a control process of the fixing system according to the embodiment. [Figure 6] 10 is a flowchart showing control of a fixing system according to a modified example of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. As shown in Fig. 1, an image forming apparatus 10 constituting an image forming system according to the present embodiment is, for example, a so-called tandem type full-color printer.

[0021] An image forming section 12 is provided inside the main body of the image forming apparatus 10. The image forming section 12 is provided with image forming units 14Y, 14M, 14C, and 14K as examples of image forming means for each of the colors yellow (Y), magenta (M), cyan (C), and black (K). The image forming units 14 are arranged in series at predetermined intervals along the horizontal direction.

[0022] Each image forming unit 14 is basically configured in the same way and includes a photosensitive drum 16 as an example of an image carrier that is rotated at a predetermined speed in the direction of arrow A, a charging device 18 consisting of a scorotron or a charging roll that uniformly charges the surface of the photosensitive drum 16, an exposure device 20 that exposes the surface of the photosensitive drum 16 to an image corresponding to each color to form an electrostatic latent image, a developing device 22 that develops the electrostatic latent image formed on the photosensitive drum 16 with toner of the corresponding color, and a cleaning device 24 that removes toner remaining on the photosensitive drum 16.

[0023] Photosensitive drum 16 is formed, for example, by coating the surface of a conductive cylindrical member with a photosensitive layer of an organic photoconductor or the like, and is rotated in the direction of arrow A at a predetermined rotational speed by a drive source not shown.

[0024] In the exposure device 20, a laser beam LB modulated according to image data is emitted from a semiconductor laser, and the laser beam LB emitted from the semiconductor laser is irradiated onto a rotating polygon mirror via a mirror, deflected and scanned by the rotating polygon mirror, and then scanned and exposed onto the surface of the photosensitive drum 16 via an fθ lens and a mirror. As a result, an electrostatic latent image according to the image data is formed on the surface of each photosensitive drum 16.

[0025] The electrostatic latent images formed on the surfaces of the photoconductor drums 16 are developed into toner images of the respective colors, yellow (Y), magenta (M), cyan (C) and black (K), by developing devices 26 of a two-component development system that contains a two-component developer consisting of, for example, toner and a carrier. Note that the developing devices 26 may be of a one-component development system that uses a one-component developer consisting only of toner.

[0026] The toner images of each color, yellow (Y), magenta (M), cyan (C), and black (K), formed sequentially on the photosensitive drum 16 of each image forming unit 14 are transferred in a superimposed state sequentially onto an intermediate transfer belt 30, which is an example of an intermediate transfer body, arranged below each image forming unit 14, by a primary transfer roll 28.

[0027] The primary transfer roll 28 is disposed opposite the photoconductor drum 16 with the intermediate transfer belt 30 interposed therebetween, and constitutes a primary transfer section T1. The intermediate transfer belt 30 is wound around a drive roll 32, a tension roll 34, a steering roll 36, a backup roll 40 with which the power supply roll 38 comes into contact, and an idler roll 42 with a predetermined tension, and is driven to circulate in the direction of arrow B at a predetermined speed substantially equal to that of the photoconductor drum 16 by the drive roll 32 which is driven to rotate by a drive motor (not shown).

[0028] The toner images of each color, yellow (Y), magenta (M), cyan (C), and black (K), transferred in multiple layers onto the intermediate transfer belt 30, are secondarily transferred onto a recording paper P, which is an example of a recording medium, by the pressure contact force and electrostatic force of a secondary transfer roll 44, which is in pressure contact with the backup roll 40 via the intermediate transfer belt 30. The recording paper P onto which the toner images of each color have been transferred is transported to a fixing device 70 by a transport belt 46 and a transport guide 48.

[0029] The secondary transfer section T2, which is an example of a transfer section, is composed of a secondary transfer roll 44 arranged on the toner image bearing surface side of the intermediate transfer belt 30, and a backup roll 40. The recording paper P onto which the toner images of each color have been transferred is fixed by the fixing device 70 using heat and pressure, and then discharged by a discharge roll (not shown) onto a discharge tray (not shown) provided outside the device main body.

[0030] In addition, recording paper P of the desired size and material is transported from a paper feed tray 52 arranged inside the main body of the device via a paper transport path 50 consisting of a paper feed roll 54 and a pair of transport rolls 56 for transporting paper to a registration roll 58, and is then transported by the registration roll 58 to the secondary transfer section T2 of the intermediate transfer belt 30 via a transport guide 64.

[0031] Residual toner remaining on the intermediate transfer belt 30 is removed by a belt cleaning device 62 disposed opposite the idler roll 42. Furthermore, the image forming unit 12 is provided with a reference sensor 66 for detecting the reference position of the intermediate transfer belt 30, and a detection sensor 68 for detecting a pattern formed on the surface of the intermediate transfer belt 30 for registration.

[0032] 2, fixing device 70 constituting the fixing system has a roll-shaped pressure member 72 and a heating member 74 that fixes a toner image onto recording paper P while rotating and transporting recording paper P between pressure member 72. In fixing device 70 in this embodiment, as an example, pressure member 72, which is the rotation driving side, is disposed on the lower side, and heating member 74, which is the driven rotation side that is rotated by pressure member 72, is disposed on the upper side.

[0033] The pressure member 72 includes a cylindrical core made of iron, stainless steel, aluminum, etc., an elastic layer made of silicone rubber or the like that coats the surface of the core, and a release layer made of PFA (perfluoroalkoxyalkane) or the like that coats the surface of the elastic layer. The pressure member 72 is configured to be rotated by a rotational driving force from a motor (not shown).

[0034] The heating member 74 has an endless belt-like fixing belt 76 and a heater 80 as an example of a sliding member that contacts the inner circumferential surface of the fixing belt 76 and heats the fixing belt 76. The fixing belt 76 is made of a synthetic resin such as polyimide resin or polyamide-imide resin, and is configured such that a release layer made of PFA or the like is provided on the surface as necessary.

[0035] The heater 80 is provided on the lower surface of a pressure contact member 78 provided on the inside of the fixing belt 76. The pressure contact member 78 is urged downward by a compression coil spring 82 provided on the inside of the fixing belt 76. In other words, the heater 80 is in contact with the inner circumferential surface of the fixing belt 76 while being urged downward by the compression coil spring 82 via the pressure contact member 78.

[0036] The area (range) where the pressure member 72 and the fixing belt 76 of the heating member 74 are in contact (pressed) with each other is defined as a nip portion N. A temperature sensor (not shown) is disposed on the surface of the heating member 74 so as to be in contact with the non-paper passing portion or out of contact with the paper passing portion.

[0037] In the fixing device 70, when the recording paper P passes through the nip portion N between the pressure member 72 and the heating member 74, the surface temperature of the heating member 74 drops as heat is absorbed by the recording paper P. For this reason, the surface temperature of the heating member 74 is constantly monitored by a temperature sensor. In addition, the rotational torque, which will be described later, is detected by the value of the current flowing through the motor.

[0038] A control unit 60 that controls the operation of each unit is disposed inside the main body of the image forming apparatus 10. A processor 61 that constitutes a fixing system is incorporated in this control unit 60. The processor 61 refers to a processor in a broad sense, and includes a general-purpose processor (e.g., a CPU: Central Processing Unit, etc.) and a dedicated processor (e.g., a GPU: Graphics Processing Unit, an ASIC: Application Specific Integrated Circuit, an FPGA: Field Programmable Gate Array, a programmable logic device, etc.).

[0039] The operations of the processor 61 may be performed not only by one processor, but also by multiple processors located at physically separate locations working together. The order of the operations of the processor 61 is not limited to the order described in this embodiment, and may be changed as appropriate.

[0040] The processor 61 controls the rotation of the pressure member 72 (and consequently the heating member 74) in a first mode at a low speed (e.g., 120 mm / s: see FIG. 3) and a second mode at a high speed (e.g., 300 mm / s) with a higher rotational torque than that in the first mode. If the rotational torque in the second mode predicted from the detection result of the rotational torque of the pressure member 72 (or the heating member 74) in the first mode is higher than a predetermined threshold value (e.g., 0.9 Nm), the rotational speed of the pressure member 72 is controlled in advance so as not to exceed the threshold value.

[0041] 4, as the usage time of the fixing device 70, that is, the total number of prints (here, printing one sheet of A4 recording paper is defined as 1 PV), increases, the rotation torque of the pressure member 72 and the heating member 74 increases. Normally, the device is designed with the increase in rotation torque in mind, but continued use increases the possibility that the grease in the sliding portion between the fixing belt 76 and the pressure member 72 will decrease or deteriorate, or that foreign matter will get mixed into the sliding surface, and at that time, the rotation torque may exceed the upper limit (e.g., 1.0 Nm) of the drive torque of the motor that rotates and drives the pressure member 72. In that case, the fixing device 70 is forced to stop, that is, the system goes down and becomes inoperable, reducing convenience.

[0042] Therefore, as described above, before rotating the pressure member 72 and the heating member 74 of the fixing device 70 in the high-speed second mode, the rotation torque in the low-speed first mode is measured, and the rotation torque in the high-speed second mode is predicted from the measured rotation torque. If the predicted rotation torque when rotating in the high-speed second mode is higher than a threshold value (e.g., 0.9 Nm: see FIG. 3), the pressure member 72 and the heating member 74 are controlled to rotate at a low speed (a rotation speed equal to or higher than the first mode and lower than the second mode, e.g., 180 mm / s: see FIG. 3) at which the rotation torque is low, and printing (fixing) is performed.

[0043] In this way, the processor 61 controls the rotational torque of the pressurizing member 72 and the heating member 74 so as not to exceed a threshold value by reducing the rotational speed of the pressurizing member 72 and the heating member 74 in advance. Note that, as shown in Fig. 3, the processor 61 can also control the rotational torque of the pressurizing member 72 and the heating member 74 so as not to exceed a threshold value by raising the temperature of the heating member 74 (heater 80). Specifically, as shown in Fig. 3, if the temperature of the heater 80 is raised by 20°C, for example, the rotational torque is reduced to 0.7 Nm at a rotational speed of 180 mm / s, and for example, the rotational torque is reduced to about 0.8 Nm at a rotational speed of 240 mm / s.

[0044] Furthermore, when the predicted rotational torque when the pressure applying member 72 and the heating member 74 are rotated in the high-speed second mode is lower than a threshold value, the processor 61 controls the pressure applying member 72 and the heating member 74 to rotate in the high-speed second mode. However, when it is determined that the rotational torque in the second mode will exceed a threshold value based on the past rotational torque transition shown in Fig. 4, the rotational speed of the pressure applying member 72 is controlled in advance so that the rotational torque does not exceed the threshold value.

[0045] Specifically, as shown in Fig. 4, the rotation torque of the pressure member 72 and the heating member 74 in the fixing device 70 gradually increases from the beginning of printing, and then decreases and levels off. Here, for example, when the total number of printed sheets is the number indicated by X1, the slope of the rotation torque is positive and there is a margin up to the threshold value (e.g., 0.9 Nm). Therefore, the processor 61 does not need to control the rotation speed of the pressure member 72 in advance so that it does not exceed the threshold value. In other words, the processor 61 rotates the pressure member 72 in the high-speed second mode.

[0046] However, for example, when the total number of prints reaches the number indicated by X2, the slope of the rotational torque is positive and there is no margin to the threshold value (e.g., 0.9 Nm). Therefore, in this case, it is determined from the past transition of the rotational torque that the rotational torque in the second mode will exceed the threshold value. Therefore, as described above, the processor 61 controls the rotational speed of the pressure member 72 in advance so that the threshold value is not exceeded.

[0047] In addition, even if the predicted rotational torque when the pressure applying member 72 and the heating member 74 are rotated in the high-speed second mode is higher than or close to the threshold value, the processor 61 rotates the pressure applying member 72 in the high-speed second mode if it is determined from the past trends in the rotational torque that the rotational torque in the second mode will not exceed the threshold value.

[0048] That is, for example, when the total number of prints reaches the number indicated by X3, there is no margin to the threshold value (e.g., 0.9 Nm), but the slope of the rotational torque is negative. Therefore, in this case, it is determined from the past transition of the rotational torque that the rotational torque in the second mode will not exceed the threshold value. Therefore, as described above, the processor 61 rotates the pressure member 72 in the high-speed second mode.

[0049] In addition, if the predicted rotational torque when the pressure member 72 and the heating member 74 are rotated in the high-speed second mode is higher than a threshold value (e.g., 0.9 Nm) consecutively (e.g., three consecutive times) each time a prediction is made, the processor 61 will not detect the rotational torque in the first mode from the next time onwards, or will set the rotational speed of the pressure member 72 and the heating member 74 during the rotational transport of the recording paper P to the low-speed first mode regardless of whether or not the rotational torque is detected.

[0050] Next, the control of the fixing system according to the present embodiment having the above-mentioned configuration will be described with reference to a flowchart.

[0051] As described above, as the usage time of the fixing device (total number of prints) increases, the rotation torque of the pressure member and the heating member increases, and when the rotation torque exceeds the upper limit of the driving torque of the motor, a system crash occurs. For this reason, in the past, a threshold was set for the driving torque of the motor, and when the driving torque exceeded the threshold, the rotation driving speed of the motor was reduced or the fixing temperature was increased to prevent a system crash. However, because the transition of the driving torque changes due to various disturbances such as the driving history of the fixing device and sudden malfunctions, it is difficult to always accurately grasp the rotation torque during printing.

[0052] Therefore, the processor 61 of the fixing system according to this embodiment executes the above-mentioned control. That is, as shown in Fig. 5, first, in step S1, a print standby operation is started. Then, in step S2, the rotation torque of the pressure member 72 and the heating member 74 in the fixing device 70 in the first mode, which is a low speed mode, is measured.

[0053] Since it takes less than 30 seconds to measure the rotational torque in the first mode, the rotational torque in the first mode is measured every time a print standby operation is started. Then, from the measured rotational torque, the rotational torque in the second mode, in which the pressure member 72 and the heating member 74 are rotated at high speed, is predicted by a Stribeck curve as shown in FIG.

[0054] If the predicted rotational torque is higher than the threshold value, the processor 61 controls the motor to reduce its rotational speed in step S3. That is, the process speed of the pressure member 72 and the heating member 74 is reduced to be lower than the rotational speed in the second mode (for example, from 300 mm / s to 180 mm / s: see FIG. 3). This prevents the rotational torque of the pressure member 72 and the heating member 74 from exceeding the threshold value, and prevents the system from going down even when printing is performed in step S4.

[0055] That is, according to this embodiment, the possibility of a system down is reduced compared to a configuration in which the rotational torque of the heating member is detected and the rotational speed of the heating member is reduced after the detected rotational torque exceeds a predetermined threshold. Note that reducing the rotational torque of the pressure member 72 and the heating member 74 is easier than applying a separate braking torque. Also, the rotational speed reduced below that of the second mode is equal to or higher than the rotational speed in the first mode (e.g., 120 mm / s).

[0056] On the other hand, if the predicted rotational torque value is lower than the threshold value, in step S5, the maximum rotational torque during printing, i.e., the rotational torque in the second mode, is predicted from the rotational torque and the past trends in rotational torque (see FIG. 4).

[0057] Then, in step S5, if it is determined that the predicted maximum rotational torque (rotational torque in the second mode) exceeds the threshold value, the process proceeds to step S3, where the processor 61 controls to reduce the rotational speed of the motor. Therefore, when the predicted rotational torque is lower than the threshold value, the possibility of a system down is reduced compared to when the rotational torque (rotational speed) in the second mode is always maintained for the heating member.

[0058] If it is determined in step S5 that the predicted maximum rotational torque (rotational torque in the second mode) does not exceed the threshold value, the process proceeds to step S4, where printing is performed at the rotational speed (rotational torque) in the second mode. Therefore, in this case, the processing speed during printing is not reduced.

[0059] 6, step S3 may be a control to increase the temperature of the heating member 74 instead of a control to decrease the process speed. As shown in Fig. 3, if the temperature of the heating member 74 is increased from 130°C to 150°C, for example, the rotation torque of the pressure member 72 and the heating member 74 decreases, so that it is easier to control so as not to exceed the threshold value compared to the case where a separate braking torque is applied.

[0060] Also, although not shown, each time the rotation torque in the first mode is measured, if the predicted rotation torque in the second mode is continuously higher than the threshold value, the detection of the rotation torque in the first mode is not performed from the next time onwards, or, regardless of the presence or absence of detection, the rotation speed of the pressure member 72 and the heating member 74 during the rotational transport of the recording paper P is set to the first mode at a low speed (e.g., 120 mm / s). This reduces the possibility of a system downtime occurring, even if the predicted rotation torque in the second mode is continuously higher than the threshold value, compared to when the torque is controlled so as not to exceed the threshold value.

[0061] Although the fixing system and the image forming system according to the present embodiment have been described above with reference to the drawings, the fixing system and the image forming system according to the present embodiment are not limited to those shown in the drawings, and various modifications, changes, and improvements are possible. For example, the rotation torque may be reduced by reducing the nip pressure formed by the pressure member 72 and the heating member 74.

[0062] Furthermore, the heating member 74 is not limited to being constituted by the fixing belt 76, and may be formed in a roll shape, similar to the pressure member 72. For example, if a cleaning blade (not shown) is applied to the peripheral surface of a roll-shaped heating member (not shown), wear powder is generated and affects the rotation torque, so the above-mentioned control is effective. In this case, the heating member may be configured to be rotationally driven by the rotational driving force from a motor.

[0063] (Additional Note) (((1))) a heating member that fixes a toner image onto a recording medium while rotating and conveying the recording medium between the pressing member and the heating member; A processor; Equipped with The processor, The rotation speed of the pressurizing member or the heating member is controlled in a first mode and a second mode having a higher rotation torque than that in the first mode; A fixing system that, when the rotational torque in the second mode predicted from the detection result of the rotational torque in the first mode is higher than a predetermined threshold value, controls the pressure member or the heating member in advance so that the rotational torque does not exceed the threshold value. (((2))) The processor, When the predicted rotational torque in the second mode is lower than the threshold value and it is determined from past trends in rotational torque that the rotational torque in the second mode will exceed the threshold value, the pressure member or the heating member is controlled in advance so that the threshold value is not exceeded (((1))). (((3))) The processor, The fixing system described in (((1))) or (((2))) controls the pressure member or the heating member in the second mode when the predicted rotational torque in the second mode is higher than the threshold value and when it is determined from past trends in rotational torque that the rotational torque in the second mode will not exceed the threshold value. (((4))) The processor, The fixing system according to any one of ((1))) to (((3))), wherein the rotation speed of the pressure member or the heating member is reduced in advance so as not to exceed the threshold value. (((5))) The processor, When the predicted rotational torque in the second mode is continuously higher than the threshold value, the rotational torque in the first mode is not detected, or, regardless of whether or not the rotational torque is detected, the rotational speed of the pressure member or the heating member during the rotational transport of the recording medium is set to the first mode ((4))). (((6))) The processor, The fixing system according to any one of ((1))) to (((3))), wherein the temperature of the heating member is increased so as not to exceed the threshold value. (((7))) a transfer section for transferring a toner image onto a recording medium; A fixing system according to any one of ((1))) to (((6))) that fixes the toner image transferred by the transfer unit onto the recording medium; An image forming system comprising:

[0064] According to the fixing system of (((1))), the possibility of a system failure can be reduced compared to a configuration in which the rotational torque of the heating member is detected and, when the detected rotational torque exceeds a predetermined threshold, the rotational speed of the heating member is reduced. According to the fixing system of (((2))), when the predicted rotational torque is lower than the threshold value, the possibility of a system failure occurring can be reduced compared to a case where the rotational torque of the heating member is always maintained. According to the fixing system of (((3))), the processing speed during printing is not reduced. According to the fixing system of (((4))), it is possible to easily reduce the rotation torque of the heating member, compared to the case where a separate braking torque is applied. According to the fixing system of (((5))), even if the predicted rotational torque is continuously higher than the threshold value, the possibility of a system failure can be reduced compared to a case where the predicted rotational torque is controlled so as not to exceed the threshold value. According to the fixing system of (((6))), it is possible to easily reduce the rotation torque of the heating member, compared to the case where a separate braking torque is applied.

[0065] According to the image forming system of (((7))), it is possible to obtain an image forming system in which the possibility of a system failure is reduced, compared to a configuration in which the rotational torque of a heating member is detected and, when the detected rotational torque exceeds a predetermined threshold value, the rotational speed of the heating member is reduced. [Explanation of symbols]

[0066] 10 Image forming device 60 Control section 61 processors 70 Fixing device 72 Pressure member 74 Heating member P Recording paper (an example of a recording medium)

Claims

1. a heating member that fixes a toner image onto a recording medium while rotating and conveying the recording medium between the pressing member and the heating member; A processor; Equipped with The processor, A rotation speed of the pressurizing member or the heating member is controlled in a first mode and a second mode having a rotation torque higher than that in the first mode; A fixing system that, when the rotational torque in the second mode predicted from the detection result of the rotational torque in the first mode is higher than a predetermined threshold value, controls the pressure member or the heating member in advance so that the rotational torque does not exceed the threshold value.

2. The processor, The fixing system described in claim 1, wherein when the predicted rotational torque in the second mode is lower than the threshold value and it is determined from past trends in rotational torque that the rotational torque in the second mode will exceed the threshold value, the pressure member or the heating member is controlled in advance so that the threshold value is not exceeded.

3. The processor, The fixing system described in claim 2, wherein when the predicted rotational torque in the second mode is higher than the threshold value and when it is determined from past trends in rotational torque that the rotational torque in the second mode will not exceed the threshold value, the pressure member or the heating member is controlled in the second mode.

4. The processor, The fixing system according to claim 1 , wherein the rotation speed of the pressure member or the heating member is reduced in advance so as not to exceed the threshold value.

5. The processor, A fixing system as described in claim 4, wherein when the predicted rotational torque in the second mode is continuously higher than the threshold value, the rotational torque in the first mode is not detected, or the rotational speed of the pressure member or the heating member during rotational transport of the recording medium is set to the first mode regardless of whether or not the rotational torque is detected.

6. The processor, The fusing system of claim 1 , wherein the temperature of the heating member is increased so as not to exceed the threshold value.

7. a transfer section for transferring a toner image onto a recording medium; The fixing system according to any one of claims 1 to 6, which fixes the toner image transferred by the transfer unit onto the recording medium; An image forming system comprising:

Images