Image forming device

Abstract

To provide an image forming apparatus that can perform, at a desired timing, an operation according to a trouble occurring in a fixing device.SOLUTION: An image forming apparatus has an image forming unit, a motor, and a control unit. The motor drives the image forming unit and outputs a signal of a magnitude according to the value of driving current. The control unit controls the motor in one of a first operation mode and a second operation mode. When the operation mode is the first operation mode, the control unit sets an upper limit and a lower limit of a first range as thresholds. When the operation mode is the second operation mode, the control unit sets an upper limit and a lower limit of a second range as thresholds. When the magnitude of the signal goes out of the first range during the drive of the motor in the first operation mode, the control unit performs a first operation. When the magnitude of the signal goes out of the second range while the motor is driven in the second operation mode, the control unit performs a second operation.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to an image forming apparatus. [Background technology]

[0002] In the image forming apparatus, the value of a parameter indicating the state of a motor that drives a fixing device is detected, and the value of the parameter is used to determine whether a malfunction has occurred in the fixing device. The parameter indicating the state of the motor is, for example, the torque of the motor, the drive current of the motor, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-040801 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the parameter value indicating the motor state varies depending on the motor's rotation speed, etc. Therefore, in the image forming apparatus described above, for example, when the motor is driven at a rotation speed different from a predetermined rotation speed, it may be difficult to accurately determine whether a malfunction has occurred in the fixing device. As a result, the image forming apparatus may not be able to perform an operation corresponding to a malfunction occurring in the fixing device at the desired timing.

[0005] The problem to be solved by the present invention is to provide an image forming apparatus that can perform an operation in response to a problem occurring in the fixing device at a desired timing. [Means for solving the problem]

[0006] An image forming apparatus according to an embodiment includes a conveying unit, an image forming unit, a fixing device, a motor, and a control unit. The conveying unit conveys a print medium. The image forming unit forms a toner image of a target image on the print medium conveyed by the conveying unit. The fixing device heats the print medium on which the toner image has been formed by the image forming unit, fixing the toner image to the print medium as the target image. The motor drives the fixing device and outputs a signal having a magnitude corresponding to the value of a drive current. The control unit performs a first operation when the magnitude of the signal falls outside a first range while driving the motor in a first operating mode, and performs a second operation when the magnitude of the signal falls outside a second range different from the first range while driving the motor in a second operating mode. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a configuration of an image forming apparatus 1. FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of the functional configuration of a control unit 100. [Figure 3] FIG. 10 is a diagram illustrating an example of a first correspondence relationship. [Figure 4] 10 is a diagram showing an example of a flow of a process for performing a first operation or a second operation among the processes performed by the image forming apparatus 1. FIG. [Figure 5] 5 is a diagram showing an example of the flow of a first abnormality process performed by the control unit 100 in ACT 190 shown in FIG. 4. FIG. [Figure 6] 5 is a diagram showing an example of the flow of second abnormality processing performed by the control unit 100 in ACT220 shown in FIG. 4. FIG. [Figure 7] FIG. 10 is a diagram illustrating an example of a second correspondence relationship. [Figure 8] FIG. 10 is a diagram showing an example of a flow of a process for performing a first operation or a second operation among the processes performed by the image forming apparatus 1 according to a fourth modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An image forming apparatus according to an embodiment will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals.

[0009] (Overview of image forming device) An overview of an image forming apparatus according to an embodiment will be described.

[0010] An image forming apparatus according to an embodiment includes a conveying unit, an image forming unit, a fixing device, a motor, and a control unit. The conveying unit conveys a print medium. The image forming unit forms a toner image of a target image on the print medium conveyed by the conveying unit. The fixing device heats the print medium after the toner image has been formed by the image forming unit, and fixes the toner image to the print medium as the target image. The motor drives the fixing device and outputs a signal having a magnitude corresponding to the value of a drive current. The control unit performs a first operation when the magnitude of the signal falls outside a first range while driving the motor in a first operating mode, and performs a second operation when the magnitude of the signal falls outside a second range different from the first range while driving the motor in a second operating mode.

[0011] This allows the image forming apparatus according to the embodiment to perform an operation in response to a problem occurring in the fixing device at a desired timing.

[0012] (Configuration of image forming device) The configuration of an image forming apparatus according to an embodiment will be described. As an example of the image forming apparatus, an image forming apparatus 1 will be described. FIG. 1 is a diagram showing an example of the configuration of the image forming apparatus 1.

[0013] The image forming apparatus 1 is an apparatus that forms an image on a print medium. For example, the image forming apparatus 1 is a multifunction device, a copier, a printer, etc. The print medium is a medium on which the image forming apparatus 1 performs processing such as image formation. The print medium may be any medium as long as it is a sheet-like medium on which an image can be formed on at least one of both sides. For example, the print medium is printing paper, plastic film, etc.

[0014] Image forming apparatus 1 includes, for example, printer unit 11, control panel 12, manual feed tray TA, and paper discharge tray TB. Image forming apparatus 1 may include other members, other devices, etc. in addition to printer unit 11, control panel 12, manual feed tray TA, and paper discharge tray TB.

[0015] The printer unit 11 includes a control unit 100 , a paper feed cassette 111 , a paper feed cassette 112 , and an image forming unit 114 .

[0016] The control unit 100 controls the entire image forming apparatus 1. In other words, the control unit 100 controls the printer unit 11, the control panel 12, and the image forming unit 114.

[0017] The paper feed cassette 111 stores the type of print media desired by the user. For example, the paper feed cassette 111 stores A4-sized plain paper.

[0018] The paper feed cassette 112 stores the type of print media desired by the user. For example, the paper feed cassette 112 stores A4-sized cardboard.

[0019] The control panel 12 includes an operation reception section and a display section.

[0020] The operation reception unit receives operations from a user. The operation reception unit is an input device. For example, the operation reception unit is a touchpad, input keys, etc. When the operation reception unit receives an operation from a user, it outputs information indicating the received operation to the control unit 100.

[0021] The display unit displays an image according to the operation received via the operation receiving unit. The display unit is an image display device. For example, the display unit is a liquid crystal display, an organic EL (Electro Luminescence) display, or the like. The display unit may be integrated with the operation receiving unit as a touch panel.

[0022] Image forming unit 114, under the control of control unit 100, transports the print medium and forms on the print medium an image indicated by image data acquired from control unit 100. For ease of explanation, forming an image on the print medium will be referred to as printing. Image forming unit 114 is an example of an image forming unit.

[0023] (Configuration of image forming unit) The configuration of the image forming unit 114 will be described.

[0024] Image forming unit 114 includes an intermediate transfer belt 20. Image forming unit 114 includes a driven roller 21, a backup roller 22, a secondary transfer roller 23, two registration rollers 24, and a manual paper feed roller 25. Image forming unit 114 includes four sets of image forming stations: image forming station 31, image forming station 32, image forming station 33, and image forming station 34. Image forming unit 114 includes a belt cleaner 40, a first detection unit 41, a second detection unit 42, and a third detection unit 43. Image forming unit 114 includes a fixing device AD, a motor MT, and a duplex printing device DF.

[0025] The intermediate transfer belt 20 is a belt onto which a toner image is primarily transferred by four sets of image forming stations. That is, a toner image is formed on the intermediate transfer belt 20. The intermediate transfer belt 20 is supported by a driven roller 21, a backup roller 22, and the like. The intermediate transfer belt 20 rotates in the direction indicated by arrow m in FIG. 1. More specifically, the image forming unit 114 rotates the intermediate transfer belt 20 in that direction using a motor (not shown) under the control of the control unit 100.

[0026] Image forming station 31 is an image forming station for forming a Y (yellow) image. Image forming station 32 is an image forming station for forming an M (magenta) image. Image forming station 33 is an image forming station for forming a C (cyan) image. Image forming station 34 is an image forming station for forming a K (black) image. In image forming unit 114, these four sets of image forming stations are arranged below intermediate transfer belt 20 in the rotation direction of intermediate transfer belt 20.

[0027] Image forming station 31 includes photosensitive drum 311, electrostatic charger 312, exposure scanning head 313, developing device 314, photosensitive cleaner 315, and primary transfer roller 316. In image forming station 31, electrostatic charger 312, exposure scanning head 313, developing device 314, photosensitive cleaner 315, and primary transfer roller 316 are arranged around photosensitive drum 311, which rotates in the direction indicated by arrow n in FIG. 1. Primary transfer roller 316 faces photosensitive drum 311 with intermediate transfer belt 20 interposed therebetween.

[0028] The configurations of the image forming stations 32, 33, and 34 are similar to that of the image forming station 31. Therefore, in the following, explanations of the configurations of the image forming stations 32, 33, and 34 will be omitted.

[0029] The secondary transfer roller 23 faces the backup roller 22 across the intermediate transfer belt 20. The secondary transfer roller 23 performs secondary transfer of the toner image that has been primarily transferred onto the intermediate transfer belt 20 onto a print medium that passes between the secondary transfer roller 23 and the intermediate transfer belt 20.

[0030] The two registration rollers 24 transport the print media taken out by a transport mechanism (not shown) from the paper feed cassette 111, the paper feed cassette 112, and the manual feed tray TA between the secondary transfer roller 23 and the intermediate transfer belt 20.

[0031] The manual paper feed roller 25 takes the print medium from the manual tray TA and conveys it to the two registration rollers 24.

[0032] The belt cleaner 40 removes toner remaining on the intermediate transfer belt 20 under the control of the control unit 100 .

[0033] The first detection unit 41 is a sensor that detects that the print medium has passed between the two registration rollers 24. In the embodiment, the passage of the print medium between the two registration rollers 24 means that the print medium is transported by the two registration rollers 24. The first detection unit 41 is provided at a position where it can detect that the print medium has passed between the two registration rollers 24. The first detection unit 41 is, for example, an optical sensor. Instead of an optical sensor, the first detection unit 41 may be another sensor that can detect that the print medium has passed between the two registration rollers 24. When the first detection unit 41 detects that the print medium has passed between the two registration rollers 24, it outputs information indicating that it has detected that the print medium has passed between the two registration rollers 24 to the control unit 100.

[0034] The second detection unit 42 is a sensor that detects that the print medium has passed between the secondary transfer roller 23 and the intermediate transfer belt 20. In the embodiment, the passage of the print medium between the secondary transfer roller 23 and the intermediate transfer belt 20 means that the print medium is being transported by the secondary transfer roller 23. The second detection unit 42 is provided at a position where it can detect that the print medium has passed between the secondary transfer roller 23 and the intermediate transfer belt 20. The second detection unit 42 is, for example, an optical sensor. Instead of an optical sensor, the second detection unit 42 may be another sensor that can detect that the print medium has passed between the secondary transfer roller 23 and the intermediate transfer belt 20. When the second detection unit 42 detects that the print medium has passed between the secondary transfer roller 23 and the intermediate transfer belt 20, it outputs information indicating that it has detected that the print medium has passed between the secondary transfer roller 23 and the intermediate transfer belt 20 to the control unit 100.

[0035] The third detection unit 43 is a sensor that detects that the print medium has been discharged to the discharge tray TB. The third detection unit 43 is provided in a position where it can detect that the print medium has been discharged to the discharge tray TB. The third detection unit 43 is, for example, an optical sensor. Instead of an optical sensor, the third detection unit 43 may be another sensor that can detect that the print medium has been discharged to the discharge tray TB. When the third detection unit 43 detects that the print medium has been discharged to the discharge tray TB, it outputs information indicating that it has detected that the print medium has been discharged to the discharge tray TB to the control unit 100.

[0036] The fixing device AD ​​includes a fixing member ADA, a heating section HT, a pressing member ADB, and a pressing force adjusting mechanism ADC.

[0037] The fixing member ADA is a member having an endless peripheral surface. For example, the fixing member ADA is a belt-shaped member. The fixing member ADA contacts the outer peripheral surface of the pressing member ADB. The fixing member ADA rotates together with the pressing member ADB with which it contacts. A heating section HT is provided inside the fixing member ADA. A support member that rotatably supports the fixing member ADA is provided inside the fixing member ADA. In FIG. 1, the support member is omitted to simplify the drawing.

[0038] The heating unit HT heats the fixing member ADA. For example, the heating unit HT includes a heater and a heated member that is heated by the heater. In this case, the heated member is in slidable contact with the fixing member ADA. The heating unit HT heats the heated member with the heater, thereby heating the fixing member ADA that is in contact with the heated member.

[0039] The pressing member ADB is a roller that contacts the outer peripheral surface of the fixing member ADA. The driving force of the motor MT is transmitted to the pressing member ADB via gears or the like. In other words, the pressing member ADB is rotated by the driving force of the motor MT.

[0040] The pressing member ADB is pressed against the outer peripheral surface of the fixing member ADA by a biasing member such as a spring. The pressing member ADB forms a nip with the fixing member ADA by being pressed against the fixing member ADA. In other words, the pressing member ADB forms a nip with the fixing member ADA by coming into contact with the fixing member ADA. The force with which the biasing member presses the pressing member ADB against the fixing member ADA is adjusted by the control unit 100 via the pressure adjustment mechanism ADC. For convenience of explanation, this force will be referred to as the pressing force. In the fixing device AD, instead of a configuration in which the pressing member ADB is pressed against the outer peripheral surface of the fixing member ADA by a biasing member, a configuration in which the fixing member ADA is pressed against the outer peripheral surface of the pressing member ADB by a biasing member may be used. In this case, the pressing force refers to the force with which the biasing member presses the fixing member ADA against the pressing member ADB.

[0041] The pressure adjustment mechanism ADC adjusts the pressing force by moving the pressing member ADB in a direction away from the fixing member ADA under control of the control unit 100. For example, the pressure adjustment mechanism ADC moves the pressing member ADB in a direction away from the fixing member ADA, thereby separating the pressing member ADB from the fixing member ADA. In this case, the pressing force is 0 N. For example, the pressure adjustment mechanism ADC moves the pressing member ADB in a direction away from the fixing member ADA, thereby adjusting the pressing force to match the force under control of the control unit 100. In a configuration in which the fixing member ADA is pressed against the outer peripheral surface of the pressing member ADB by a biasing member, the pressure adjustment mechanism ADC adjusts the pressing force by moving the fixing member ADA in a direction away from the pressing member ADB under control of the control unit 100.

[0042] The fixing device AD ​​is a device that fixes the toner image onto the print medium after the toner image has been secondarily transferred onto it by the secondary transfer roller 23. More specifically, the fixing device AD ​​applies pressure and heat to the print medium while transporting it using the fixing member ADA and the pressing member ADB. In this way, the fixing device AD ​​fixes the toner image that has been secondarily transferred onto the print medium onto the print medium. As a result, an image is formed on the print medium.

[0043] The motor MT drives the fixing device AD. The motor MT includes a circuit that outputs a signal to the control unit 100, the magnitude of which corresponds to the value of the driving current of the motor MT. This circuit may be any circuit that can output the signal to the control unit 100. The motor MT is, for example, a servo motor. The motor MT rotates the pressing member ADB via gears or the like. Instead of a servo motor, the motor MT may be another type of motor that can be controlled by the control unit 100.

[0044] The double-sided printing device DF is a device that transports the print medium, after an image has been formed on the front side by the fixing device AD, to two registration rollers 24. The print medium is transported to the double-sided printing device DF after the front and back sides have been turned over. Therefore, the print medium transported between the two registration rollers 24 via the double-sided printing device DF has an image formed on the back side via the secondary transfer roller 23 and the fixing device AD.

[0045] (Image forming unit operation) The operation of the image forming unit 114 will now be described.

[0046] First, the operation of the four image forming stations will be described, taking the operation of the image forming station 31 as an example.

[0047] In the image forming station 31, the photosensitive drum 311 is charged by the electrostatic charger 312 and then exposed by the exposure scanning head 313. In this way, the image forming station 31 forms an electrostatic latent image on the photosensitive drum 311. Then, the image forming station 31 develops the electrostatic latent image on the photosensitive drum 311 with the developing device 314. The developing device 314 develops the electrostatic latent image on the photosensitive drum 311 into a toner image using a two-component developer formed of toner and carrier. In this way, a toner image is formed on the photosensitive drum 311. A primary transfer roller 316 primarily transfers the toner image formed on the photosensitive drum 311 to the intermediate transfer belt 20. After this primary transfer, a photosensitive cleaner 315 removes any toner remaining on the photosensitive drum 311.

[0048] Each of image forming stations 31, 32, 33, and 34 forms a color toner image on intermediate transfer belt 20 by primary transfer roller 316. The color toner image is formed by sequentially overlapping toner images of Y (yellow), M (magenta), C (cyan), and K (black).

[0049] Next, the operation of the secondary transfer roller 23 will be described. The secondary transfer roller 23 performs secondary transfer of the color toner images on the intermediate transfer belt 20 all at once onto the print medium passing between the secondary transfer roller 23 and the intermediate transfer belt 20. In the following description, the term "toner image" may refer to either a color toner image or a toner image of only one color. The toner image may also be a toner image using a decolorizable toner.

[0050] Next, the operation of conveying the print medium among the operations of the image forming unit 114 will be described.

[0051] A conveying mechanism (not shown) bends the print medium removed from paper feed cassette 111, paper feed cassette 112, and manual tray TA at the nip between the two registration rollers 24. This aligns the leading edge of the print medium. The two registration rollers 24 then convey the print medium between secondary transfer roller 23 and intermediate transfer belt 20 in accordance with the timing at which image forming unit 114 transfers a toner image onto the print medium. The conveying paths along which the print media removed from paper feed cassette 111, paper feed cassette 112, and manual tray TA are conveyed to the two registration rollers 24 merge at a junction PA shown in FIG. 1.

[0052] Within image forming unit 114, three transport paths are formed by two registration rollers 24, fixing device AD, and multiple rollers within duplex printing device DF: transport path LA, transport path LB, and transport path LC. Transport path LA is the transport path from junction PA to branch point PB shown in FIG. 1. Transport path LB is the transport path that passes through duplex printing device DF and is the transport path from branch point PB to junction point PA. Transport path LC is the transport path from branch point PB to paper discharge tray TB.

[0053] The two registration rollers 24 begin to rotate in alignment with the position of the toner image on the rotating intermediate transfer belt 20, and move the print medium to the position of the secondary transfer roller 23. As a result, the toner image formed on the intermediate transfer belt 20 is secondarily transferred to the print medium by the secondary transfer roller 23. After the toner image has been secondarily transferred to the print medium, the secondary transfer roller 23 transports the print medium along the transport path LA to the fixing device AD. The fixing device AD ​​fixes the toner image secondarily transferred onto the print medium transported from the secondary transfer roller 23 to the print medium as it is transported. As a result, the secondarily transferred toner image is formed as an image on the print medium. After the image has been formed on the print medium, the fixing device AD ​​transports the print medium to the transport path LC. The print medium transported to the transport path LC is then ejected by rollers (not shown).

[0054] In the case of double-sided printing, after an image is formed on the front side and the entire print medium passes through branching section PB, rollers (not shown) switch back to transport the print medium to transport path LB. This flips the front and back sides of the print medium over. Then, multiple rollers in double-sided printing device DF transport the print medium along transport path LB to the nip between two registration rollers 24. The print medium, with its front and back sides flipped over, is then transported along transport path LA via the two registration rollers 24, where the toner image is fixed by fixing device AD. This forms an image on the back side of the print medium. Fixing device AD ​​transports the print medium, with the image formed on the back side, to transport path LC and ejects it.

[0055] In this way, the secondary transfer roller 23, the two registration rollers 24, the fixing device AD, and various rollers in the double-sided printing device DF constitute a transport section in the image forming apparatus 1 that transports the print medium.

[0056] (Functional configuration of the control unit) The functional configuration of the control unit 100 will be described with reference to Fig. 2. Fig. 2 is a diagram showing an example of the functional configuration of the control unit 100.

[0057] 2, the control unit 100 is communicably connected to each of the printer unit 11 and the control panel 12. The control unit 100 includes an arithmetic unit 1101, a storage device 1102, a data receiving unit 1103, and an image data developing unit 1104.

[0058] The arithmetic unit 1101 is, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), etc. The arithmetic unit 1101 controls the printer unit 11 and the control panel 12 according to an image processing program stored in a storage device 1102.

[0059] The storage device 1102 is a read only memory (ROM), a random access memory (RAM), a hard disk drive (HDD), a solid state drive (SSD), etc. The storage device 1102 may be separate from the control unit 100.

[0060] The data receiving unit 1103 receives print data (for example, data written in a page description language) indicating an image to be printed from a host such as a PC (Personal Computer), and stores the received print data in the storage device 1102.

[0061] The image data expansion unit 1104 determines printing conditions from the print data stored in the memory device 1102 by the data receiving unit 1103, and expands the data into data that can be printed by the printer unit 11 (e.g., raster data, etc.) and stores it in the memory device 1102.

[0062] (Operation mode of image forming device) The following describes the operation modes of the image forming apparatus 1. The image forming apparatus 1 can perform an operation of forming an image on a print medium in one of a plurality of operation modes depending on the type of print medium. As an example, a case will be described in which the image forming apparatus 1 performs an operation of forming an image on a print medium in one of a first operation mode and a second operation mode depending on the type of print medium.

[0063] The first operating mode is an operating mode in which the motor MT is driven at a first rotation speed. For example, when forming an image on A4-sized plain paper, the image forming apparatus 1 performs an operation of forming an image on the plain paper in the first operating mode. The first rotation speed is, for example, 1500 rpm. The first rotation speed may be slower or faster than 1500 rpm.

[0064] The second operating mode is an operating mode in which the motor MT is driven at a second rotation speed. For example, when forming an image on A4-sized thick paper, the image forming apparatus 1 performs an operation of forming an image on the thick paper in the second operating mode. The second rotation speed is, for example, 940 rpm. The second rotation speed may be slower or faster than 940 rpm.

[0065] (Relationship between the motor drive current and the signal output from the motor) The relationship between the value of the drive current of the motor MT and the magnitude of the signal output from the motor MT will be described. For convenience of explanation, the value of the drive current of the motor MT will be referred to as the drive current value. For convenience of explanation, the signal will be referred to as the motor signal. For convenience of explanation, the magnitude of the motor signal will be referred to as the motor signal value. For convenience of explanation, the relationship between the drive current value and the motor signal value will be referred to as the first correspondence relationship. Figure 3 is a diagram showing an example of the first correspondence relationship.

[0066] The horizontal axis of the graph shown in FIG. 3 represents the drive current value. The drive current value varies depending on the load on the motor MT. For example, when the fixing device AD ​​driven by the motor MT is operating normally, the drive current value is within the normal range shown in FIG. 3. For example, when a contact failure occurs between the fixing member ADA and the pressing member ADB in the fixing device AD ​​driven by the motor MT, the drive current value is within the first abnormal range shown in FIG. 3. For example, when the lubricant in the fixing member ADA in the fixing device AD ​​driven by the motor MT is depleted, the drive current value is within the second abnormal range shown in FIG. 3.

[0067] The vertical axis of the graph shown in Figure 3 represents the motor signal value. The motor signal value changes depending on the combination of the drive current value and the rotation speed of the motor MT. The solid line plotted on the graph represents the first correspondence relationship when the image forming apparatus 1 is operating in the first operation mode. The dotted line plotted on the graph represents the first correspondence relationship when the image forming apparatus 1 is operating in the second operation mode.

[0068] As shown in FIG. 3 , the motor signal value corresponding to the drive current value indicating the boundary between the normal range and the first abnormal range differs between when the image forming apparatus 1 is operating in the first operating mode and when the image forming apparatus 1 is operating in the second operating mode. In the example shown in FIG. 3 , the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the first operating mode is greater than the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the second operating mode. In FIG. 3 , the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the first operating mode is indicated by a threshold value THAB. In FIG. 3 , the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the second operating mode is indicated by a threshold value THBB. On the other hand, in this example, the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the second operating mode is smaller than the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the second operating mode. In FIG. 3, the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the first operating mode is indicated by the threshold value THAA. In FIG. 3, the motor signal value corresponding to the drive current value indicating the boundary when the image forming apparatus 1 is operating in the second operating mode is indicated by the threshold value THBA. For convenience of explanation, the range from the threshold value THAA to the threshold value THAB will be referred to as the first range. For convenience of explanation, the range from the threshold value THBA to the threshold value THBB will be referred to as the second range. The second range is a range in which at least one of the upper limit value and the lower limit value is different from the first range. In the example shown in FIG. 3, the second range is different from the first range in both the upper limit value and the lower limit value.

[0069] (Processing of performing the first or second operation among the processing performed by the image forming apparatus) Among the processes performed by the image forming apparatus 1, the process of performing the first operation or the second operation will be described.

[0070] The first operation is an operation performed by the image forming apparatus 1 in the first operating mode, including an operation related to the motor signal value being outside the first range. For example, the first operation includes an operation of outputting notification information to an information processing device communicably connected to the image forming apparatus 1. This notification information includes, for example, information indicating that the motor signal value is outside the first range, information indicating that a malfunction has occurred in the fixing device AD, etc. For example, the first operation includes an operation of stopping the formation of an image on a print medium. For example, the first operation includes an operation of stopping the driving of the fixing device AD. The first operation may be configured to include other operations instead of some or all of these operations, or in addition to all of these operations.

[0071] The second operation is an operation performed by the image forming apparatus 1 in the second operating mode, including an operation related to the motor signal value falling outside the second range. For example, the second operation includes an operation of outputting notification information to an information processing device communicatively connected to the image forming apparatus 1. This notification information includes, for example, information indicating that the motor signal value has fallen outside the second range or information indicating that a malfunction has occurred in the fixing device AD. For example, the second operation includes an operation of stopping the formation of an image on a print medium. For example, the second operation includes an operation of stopping the driving of the fixing device AD. The second operation may be configured to include other operations instead of some or all of these operations, or in addition to all of these operations. Some or all of the one or more operations included in the second operation may be the same as one or more operations included in the first operation, or may be different from one or more operations included in the first operation.

[0072] 4 is a diagram showing an example of the flow of a process for performing the first operation or the second operation among the processes performed by the image forming apparatus 1. For convenience of explanation, the image formed on the printing medium by the image forming apparatus 1 will be referred to as a target image.

[0073] The control unit 100 waits until the printing operation starts (ACT110). For example, when the control unit 100 receives a print job, it determines to start the printing operation. In this case, the print job includes information indicating the type of print medium on which the target image is to be formed. In the embodiment, the printing operation refers to an operation performed by the image forming apparatus 1, including transporting the print medium and forming the target image on the print medium. In the flowchart shown in FIG. 4, a description of the flow of the printing operation process performed by the image forming apparatus 1 is omitted.

[0074] When the control unit 100 determines to start the printing operation (ACT110-YES), it identifies the type of print medium on which the target image is to be formed based on information included in the print job. After identifying the type, the control unit 100 sets the operating mode of the image forming apparatus 1 to an operating mode corresponding to the identified type. After setting the operating mode of the image forming apparatus 1, the control unit 100 starts the printing operation and also starts a contact operation (ACT120). The contact operation is an operation performed by the image forming apparatus 1 in which the pressing member ADB is brought into contact with the outer peripheral surface of the fixing member ADA in the fixing device AD. In ACT120, the control unit 100 controls the pressing force adjustment mechanism ADC to start the contact operation.

[0075] Next, the control unit 100 waits until the contact operation started in ACT120 is completed (ACT130). For example, the control unit 100 determines that the contact operation is completed when the pressing force matches a predetermined force. For example, the control unit 100 may be configured to detect the pressing force using a pressure sensor, may be configured to detect it based on the position of the pressing member ADB, or may be configured to detect it using some other method.

[0076] When the control unit 100 determines that the contact operation started in ACT120 has been completed (ACT130-YES), it sets a threshold value (ACT140). Specifically, in ACT140, the control unit 100 sets a threshold value corresponding to the current operation mode of the image forming apparatus 1 as the threshold value for the motor signal value. For example, when the current operation mode of the image forming apparatus 1 is a first operation mode, the control unit 100 sets a threshold value THAA, which is the upper limit of a first range, and a threshold value THAB, which is the lower limit of the first range, as the threshold value for the motor signal value. This allows the control unit 100 to determine whether the motor signal value has fallen outside the first range, which is the range from the threshold value THAA to the threshold value THAB. For example, when the current operation mode of the image forming apparatus 1 is a second operation mode, the control unit 100 sets a threshold value THBA, which is the upper limit of a second range, and a threshold value THBB, which is the lower limit of the second range, as the threshold value for the motor signal value. This allows the control unit 100 to determine whether or not the motor signal value falls outside the second range, which is the range from the threshold value THBA to the threshold value THBB.

[0077] Next, control unit 100 drives motor MT at a rotation speed corresponding to the current operation mode of image forming apparatus 1, thereby starting rotation of pressing member ADB (ACT150). In other words, control unit 100 starts driving fixing device AD ​​in ACT150. For example, in ACT150, if the current operation mode of image forming apparatus 1 is the first operation mode, control unit 100 drives motor MT at 1500 rpm. For example, in ACT150, if the current operation mode of image forming apparatus 1 is the second operation mode, control unit 100 drives motor MT at 940 rpm.

[0078] Next, the control unit 100 controls the heater of the heating unit HT to start heating the fixing member ADA (ACT160).

[0079] Next, the control unit 100 acquires the motor signal and determines whether the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT 140 (ACT 170). The lower limit value is the smaller of the threshold values ​​set by the control unit 100 in ACT 140.

[0080] When the control unit 100 determines that the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT140 (ACT170-YES), it stores contact failure information in the storage device 1102 (ACT180). The contact failure information is information including information indicating that contact failure has occurred between the fixing member ADA and the pressing member ADB in the fixing device AD ​​driven by the motor MT. The contact failure information may be configured to include other information in addition to the information indicating that contact failure has occurred between the fixing member ADA and the pressing member ADB in the fixing device AD ​​driven by the motor MT.

[0081] Next, the control unit 100 performs first abnormality processing (ACT190). The first abnormality processing is processing that performs the 11th or 12th operation as an operation corresponding to the current operation mode of the image forming apparatus 1. The 11th operation is the first operation that the image forming apparatus 1 operating in the first operation mode performs in the first abnormality processing. The 12th operation is the second operation that the image forming apparatus 1 operating in the second operation mode performs in the first abnormality processing. The flow of processing by the image forming apparatus 1 to perform the first abnormality processing will be described later. After performing the first abnormality processing, the control unit 100 ends the processing of the flowchart shown in FIG. 4.

[0082] On the other hand, when the control unit 100 determines that the motor signal value of the acquired motor signal is equal to or greater than the lower limit value set in ACT 140 (ACT 170-NO), it determines (ACT 200) whether the motor signal value of the acquired motor signal is greater than the upper limit value set in ACT 140. The upper limit value is the larger of the threshold values ​​set by the control unit 100 in ACT 140.

[0083] When the control unit 100 determines that the motor signal value of the acquired motor signal is greater than the upper limit set in ACT140 (ACT200-YES), it stores lubricant depletion information in the storage device 1102 (ACT210). The lubricant depletion information is information that includes information indicating that the lubricant in the fixing member ADA in the fixing device AD ​​driven by the motor MT has been depleted. The lubricant depletion information may be configured to include other information in addition to the information indicating that the lubricant in the fixing member ADA in the fixing device AD ​​driven by the motor MT has been depleted.

[0084] Next, the control unit 100 performs second abnormality processing (ACT220). The second abnormality processing is processing that performs operation 21 or operation 22 as an operation corresponding to the current operation mode of the image forming apparatus 1. Operation 21 is the first operation that the image forming apparatus 1 operating in the first operation mode performs in the second abnormality processing. Operation 22 is the second operation that the image forming apparatus 1 operating in the second operation mode performs in the second abnormality processing. The flow of processing by the image forming apparatus 1 to perform the second abnormality processing will be described later. After performing the second abnormality processing, the control unit 100 ends the processing of the flowchart shown in FIG. 4.

[0085] On the other hand, if the control unit 100 determines that the motor signal value of the acquired motor signal is equal to or less than the upper limit set in ACT140 (ACT200-NO), it determines whether the printing operation started in ACT120 has ended (ACT230). For example, if the control unit 100 acquires information from the third detection unit 43 indicating that it has detected that the print medium has been discharged to the paper discharge tray TB, it determines that the printing operation has ended. On the other hand, for example, if the control unit 100 does not acquire information from the third detection unit 43 indicating that it has detected that the print medium has been discharged to the paper discharge tray TB, it determines that the printing operation has not ended. The control unit 100 may be configured to determine whether the printing operation has ended using another method.

[0086] If the control unit 100 determines that the printing operation started in ACT120 has not finished (ACT230-NO), it transitions to ACT170, acquires a motor signal, and again determines whether the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT140.

[0087] On the other hand, if the control unit 100 determines that the printing operation started in ACT120 has ended (ACT230-YES), it ends the processing of the flowchart shown in FIG.

[0088] (First abnormality processing) The first abnormality processing will be described. FIG. 5 is a diagram showing an example of the flow of the first abnormality processing performed by the control unit 100 in ACT190 shown in FIG. 4. The operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT340, ACT350, and ACT370 shown in FIG. 5 are an example of an eleventh operation. The operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT340, ACT350, and ACT380 shown in FIG. 5 are an example of a twelfth operation. In other words, the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT340, and ACT350 shown in FIG. 5 are common to both the eleventh and twelfth operations.

[0089] The control unit 100 controls the heater of the heating unit HT to stop heating the fixing member ADA (ACT310).

[0090] Next, the control unit 100 controls the motor MT to stop the rotation of the pressing member ADB (ACT320).

[0091] Next, the control unit 100 stops the printing operation started in ACT120 shown in FIG. 4 (ACT330).

[0092] Next, the control unit 100 transmits first abnormality notification information (ACT340). The first abnormality notification information is information including, for example, contact failure information. Instead of or in addition to the contact failure information, the first abnormality notification information may include information indicating that the motor signal value is outside the first range. The first abnormality notification information may include other information in addition to either or both of these two pieces of information. The destination to which the control unit 100 transmits the first abnormality notification information in ACT340 is an information processing device or the like communicatively connected to the image forming apparatus 1. The information processing device may be, for example, a personal computer (PC) of a company that performs maintenance on the image forming apparatus 1, or an information processing terminal of an administrator that manages the image forming apparatus 1, but is not limited to these. The information processing terminal may be, for example, a multi-function mobile phone terminal (smartphone), a mobile phone terminal, a tablet PC, a notebook PC, a personal digital assistant (PDA), a desktop PC, etc., but is not limited to these. The first abnormality notification information is an example of the notification information described above.

[0093] Next, the control unit 100 displays the first abnormality notification information (ACT350). In ACT350, the control unit 100 displays the first abnormality notification information on a display unit of the control panel 12, a display unit of an information processing device communicably connected to the image forming apparatus 1, or the like. The information processing device is, for example, a PC of a company that performs maintenance on the image forming apparatus 1, an information processing terminal of an administrator that manages the image forming apparatus 1, or the like, but is not limited to these.

[0094] Next, the control unit 100 determines whether the current operation mode of the image forming apparatus 1 is the first operation mode (ACT360).

[0095] When the control unit 100 determines that the current operation mode of the image forming apparatus 1 is the first operation mode (ACT360-YES), it performs a first additional operation (ACT370). The first additional operation may be any operation that can be additionally performed by the image forming apparatus 1 operating in the first operation mode in addition to the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT340, and ACT350 shown in Fig. 5. After performing the process of ACT370, the control unit 100 ends the process of the flowchart shown in Fig. 5.

[0096] On the other hand, when the control unit 100 determines that the current operation mode of the image forming apparatus 1 is the second operation mode (ACT360-NO), it performs a second additional operation (ACT380). The second additional operation may be any operation that can be additionally performed by the image forming apparatus 1 operating in the second operation mode in addition to the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT340, and ACT350 shown in Fig. 5. After performing the process of ACT380, the control unit 100 ends the process of the flowchart shown in Fig. 5.

[0097] 5, some of the processes may be omitted from ACT 310, ACT 320, ACT 330, ACT 340, ACT 350, ACT 370, and ACT 380. In the eleventh operation, some of the processes may be omitted from ACT 310, ACT 320, ACT 330, ACT 340, ACT 350, and ACT 370. In the twelfth operation, some of the processes may be omitted from ACT 310, ACT 320, ACT 330, ACT 340, ACT 350, and ACT 380.

[0098] 5, some or all of the processes in ACT 310, ACT 320, ACT 330, ACT 340, ACT 350, and ACT 360 may be performed in a different order or in parallel, with the exception that the processes in ACT 370 and ACT 380 are performed after ACT 360.

[0099] (Second abnormality processing) The second abnormality processing will now be described. FIG. 6 is a diagram showing an example of the flow of the second abnormality processing performed by the control unit 100 in ACT220 shown in FIG. 4. ACT310, ACT320, ACT330, and ACT360 shown in FIG. 6 are similar to ACT310, ACT320, ACT330, and ACT360 shown in FIG. 5, respectively, and therefore description thereof will be omitted. The operation of the image forming apparatus 1 performed by the processing of ACT310, ACT320, ACT330, ACT410, ACT420, and ACT430 shown in FIG. 6 is an example of the 21st operation. The operation of the image forming apparatus 1 performed by the processing of ACT310, ACT320, ACT330, ACT410, ACT420, and ACT440 shown in FIG. 6 is an example of the 22nd operation. That is, the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT410, and ACT420 shown in FIG. 6 are common to both the 21st operation and the 22nd operation.

[0100] In the flowchart shown in FIG. 6, after performing the process of ACT330, the control unit 100 transmits second abnormality notification information (ACT410). The second abnormality notification information is information including, for example, lubricant depletion information. Instead of or in addition to the lubricant depletion information, the second abnormality notification information may be information including information indicating that the motor signal value has fallen out of the second range. The second abnormality notification information may be configured to include other information in addition to either or both of these two pieces of information. The destination to which the control unit 100 transmits the second abnormality notification information in ACT410 is an information processing device or the like communicatively connected to the image forming apparatus 1. The information processing device may be, for example, a PC of a company that performs maintenance on the image forming apparatus 1 or an information processing terminal of an administrator that manages the image forming apparatus 1, but is not limited to these. The second abnormality notification information is an example of the notification information described above.

[0101] Next, the control unit 100 displays the second abnormality notification information (ACT420). In ACT420, the control unit 100 displays the second abnormality notification information on a display unit of the control panel 12, a display unit of an information processing device communicably connected to the image forming apparatus 1, or the like. The information processing device is, for example, a PC in a company that performs maintenance on the image forming apparatus 1, an information processing terminal of an administrator that manages the image forming apparatus 1, or the like, but is not limited to these.

[0102] In ACT360 shown in Fig. 6, if the control unit 100 determines that the current operation mode of the image forming apparatus 1 is the first operation mode, it performs a third additional operation (ACT430). The third additional operation may be any operation that can be additionally performed by the image forming apparatus 1 operating in the first operation mode in addition to the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT410, and ACT420 shown in Fig. 6. After performing the process of ACT430, the control unit 100 ends the process of the flowchart shown in Fig. 6.

[0103] On the other hand, in ACT360 shown in Fig. 6, if the control unit 100 determines that the current operation mode of the image forming apparatus 1 is the second operation mode, it performs a fourth additional operation (ACT440). The fourth additional operation may be any operation that can be additionally performed by the image forming apparatus 1 operating in the second operation mode in addition to the operations of the image forming apparatus 1 performed by the processes of ACT310, ACT320, ACT330, ACT410, and ACT420 shown in Fig. 6. After performing the process of ACT440, the control unit 100 ends the process of the flowchart shown in Fig. 6.

[0104] 6, some of the processes in ACT 310, ACT 320, ACT 330, ACT 410, ACT 420, ACT 430, and ACT 440 may be omitted. In the 21st operation, some of the processes in ACT 310, ACT 320, ACT 330, ACT 410, ACT 420, and ACT 430 may be omitted. In the 22nd operation, some of the processes in ACT 310, ACT 320, ACT 330, ACT 410, ACT 420, and ACT 440 may be omitted.

[0105] 6, some or all of the processes in ACT310, ACT320, ACT330, ACT410, ACT420, and ACT360 may be performed in a different order or in parallel, with the exception that the processes in ACT430 and ACT440 are performed after ACT360.

[0106] As described above, the image forming apparatus 1 according to the embodiment performs the first operation when the motor signal value falls outside the first range while driving the motor MT in the first operation mode, and performs the second operation when the motor signal value falls outside the second range while driving the motor MT in the second operation mode. This allows the image forming apparatus 1 to perform an operation in response to a malfunction occurring in the fixing device AD ​​at a desired timing.

[0107] (Modification 1 of the embodiment) A first modification of the embodiment will be described. In the first modification of the embodiment, the control unit 100 sets a threshold value THCA instead of the threshold value THAA, a threshold value THCB instead of the threshold value THAB, a threshold value THDA instead of the threshold value THBA, and a threshold value THDB instead of the threshold value THBB. The threshold value THCA is a value smaller than the threshold value THAA by a predetermined percentage. For example, the threshold value THCA is a value smaller than the threshold value THAA by 10% of the threshold value THAA. The threshold value THCB is a value larger than the threshold value THAB by a predetermined percentage. For example, the threshold value THCB is a value larger than the threshold value THAB by 10% of the threshold value THAB. In other words, the first range according to the first modification of the embodiment is a range narrower than the first range according to the embodiment and is a range included within the first range according to the embodiment. For example, the threshold value THDA is a value smaller than the threshold value THBA by 10% of the threshold value THBA. The threshold value THDB is a value larger than the threshold value THBB by a predetermined percentage. For example, the threshold value THDB is greater than the threshold value THBB by 10% of the threshold value THBB. That is, the second range according to the first modification of the embodiment is narrower than the second range according to the embodiment and is included within the second range according to the embodiment.

[0108] In a first modification of the embodiment, the first abnormality notification information includes, for example, information indicating that a contact failure between the fixing member ADA and the pressing member ADB is likely to occur in the fixing device AD ​​driven by the motor MT, and information indicating that the motor signal value has deviated from the first range. The first abnormality notification information may include other information in addition to either or both of these two pieces of information. In the first modification of the embodiment, the processes ACT310, ACT320, and ACT330 are omitted from the first abnormality processing. In the first modification of the embodiment, the second abnormality notification information includes information indicating that a lubricant depletion in the fixing member ADA is likely to occur in the fixing device AD ​​driven by the motor MT, and information indicating that the motor signal value has deviated from the first range. The second abnormality notification information may include other information in addition to either or both of these two pieces of information. In the first modification of the embodiment, the processes ACT310, ACT320, and ACT330 are omitted from the second abnormality processing. As a result, the image forming apparatus 1 can perform the following operations: notify that there is a high possibility of a malfunction occurring in the fixing device AD, or display that there is a high possibility of a malfunction occurring in the fixing device AD, before a malfunction occurs in the fixing device AD, through the first operation or the second operation.

[0109] (Modification 2 of the embodiment) A second modification of the embodiment will be described. In the second modification of the embodiment, the control unit 100 may be configured to perform the determination processes of ACT170 and ACT200 shown in Fig. 4 using a machine learning model. In this case, the threshold set in ACT140 shown in Fig. 4 may be incorporated into the machine learning model.

[0110] (Modification 3 of the embodiment) A third modification of the embodiment will be described. In the third modification, the control unit 100 may perform the determination processes of ACT170 and ACT200 shown in FIG. 4 based on a detection difference value instead of the motor signal value. The detection difference value is the difference between the motor signal value and a predetermined reference value. When the process of ACT170 is performed based on the detection difference value and the operation mode of the image forming apparatus 1 is the first operation mode, the control unit 100 determines in ACT170 whether the detection difference value is smaller than the difference between the threshold value THAB and the reference value. When the process of ACT200 is performed based on the detection difference value and the operation mode of the image forming apparatus 1 is the first operation mode, the control unit 100 determines in ACT200 whether the detection difference value is larger than the difference between the threshold value THAA and the reference value. When the processing of ACT170 is performed based on the detected difference value and when the operating mode of the image forming apparatus 1 is the second operating mode, the control unit 100 determines whether or not the detected difference value is smaller than the difference value between the threshold value THBB and the reference value in ACT170. When the processing of ACT170 is performed based on the detected difference value and when the operating mode of the image forming apparatus 1 is the second operating mode, the control unit 100 determines whether or not the detected difference value is larger than the difference value between the threshold value THBA and the reference value in ACT200.

[0111] As a result, even if the correspondence between the drive current value and the motor signal value varies for each of the multiple image forming devices 1 due to individual differences in the motor MT, each image forming device 1 can accurately perform operations in response to malfunctions occurring in the fixing device AD ​​at the desired timing.

[0112] (Fourth Modification of the Embodiment) A fourth modified example of the embodiment will now be described. In the fourth modified example of the embodiment, the difference between the first operation mode and the second operation mode is not the rotation speed of the motor MT but the magnitude of the pressing force.

[0113] The first operating mode in the fourth modified embodiment is an operating mode in which, when the pressing member ADB is pressed against the fixing member ADA by the biasing member, the motor MT is driven while pressing the pressing member ADB against the fixing member ADA with a pressing force of a first magnitude. In other words, the first operating mode is an operating mode in which the motor MT is driven while the pressing member ADB and the fixing member ADA are in contact with each other with a pressing force of a first magnitude. For example, when forming an image on A4-sized plain paper, the image forming apparatus 1 performs an operation of forming an image on the plain paper in the first operating mode. The pressing force of the first magnitude is, for example, 400 N. The pressing force of the first magnitude may be a force smaller than 400 N or a force larger than 400 N.

[0114] The second operating mode in the fourth modified embodiment is an operating mode in which, when the pressing member ADB is pressed against the fixing member ADA by the biasing member, the motor MT is driven while pressing the pressing member ADB against the fixing member ADA with a pressing force of a second magnitude. In other words, the second operating mode is an operating mode in which the motor MT is driven while the pressing member ADB and the fixing member ADA are in contact with each other with a pressing force of a second magnitude. For example, when forming an image on A4-sized cardboard, the image forming apparatus 1 performs an operation of forming an image on the cardboard in the second operating mode. The second pressing force is, for example, 100 N. The second pressing force may be a force smaller than 100 N or a force larger than 100 N.

[0115] 7 is a diagram showing an example of the second correspondence relationship between the drive current value and the motor signal value in the fourth modification of the embodiment.

[0116] The horizontal axis of the graph shown in Figure 7 represents the drive current value. The drive current value changes depending on the load on the motor MT. The vertical axis of the graph represents the motor signal value. The solid line plotted on the graph represents the second correspondence relationship when the image forming apparatus 1 operates in the first operation mode and the second operation mode.

[0117] For example, when the operation mode of the image forming apparatus 1 is the first operation mode and the fixing device AD ​​driven by the motor MT is operating normally, the drive current value indicates a value within the normal range from the value DAA to the value DAB shown in Fig. 7. For example, when the operation mode of the image forming apparatus 1 is the first operation mode and there is poor contact between the fixing member ADA and the pressing member ADB in the fixing device AD ​​driven by the motor MT, the drive current value indicates a value smaller than the value DAB shown in Fig. 7. For example, when the operation mode of the image forming apparatus 1 is the first operation mode and there is depletion of the lubricant in the fixing member ADA in the fixing device AD ​​driven by the motor MT, the drive current value indicates a value larger than the value DAA shown in Fig. 7.

[0118] For example, when the operation mode of the image forming apparatus 1 is the second operation mode and the fixing device AD ​​driven by the motor MT is operating normally, the drive current value indicates a value within the normal range from value DBA to value DBB shown in Fig. 7. For example, when the operation mode of the image forming apparatus 1 is the second operation mode and there is poor contact between the fixing member ADA and the pressing member ADB in the fixing device AD ​​driven by the motor MT, the drive current value indicates a value smaller than value DBB shown in Fig. 7. For example, when the operation mode of the image forming apparatus 1 is the second operation mode and there is depletion of lubricant in the fixing member ADA in the fixing device AD ​​driven by the motor MT, the drive current value indicates a value larger than value DBA shown in Fig. 7.

[0119] The threshold value THCA shown in FIG. 7 indicates the motor signal value when the drive current value is value DAA. The threshold value THCB shown in FIG. 7 indicates the motor signal value when the drive current value is value DAB. The threshold value THDA shown in FIG. 7 indicates the motor signal value when the drive current value is value DBA. The threshold value THDB shown in FIG. 7 indicates the motor signal value when the drive current value is value DBB. For convenience of explanation, the range from threshold value THCA to threshold value THCB will be referred to as the third range. The third range is a modified example of the first range in the embodiment. For convenience of explanation, the range from threshold value THDA to threshold value THDB will be referred to as the fourth range. The fourth range is a modified example of the second range in the embodiment.

[0120] The fourth range is a range in which at least one of the upper limit value and the lower limit value is different from the third range. In the example shown in FIG. 7, the fourth range is different from the third range in both the upper limit value and the lower limit value. Therefore, when the operation mode of the image forming apparatus 1 is the first operation mode, the control unit 100 can determine whether the motor signal value has deviated from the third range by using the threshold values ​​THCA and THCB. When the operation mode of the image forming apparatus 1 is the second operation mode, the control unit 100 can determine whether the motor signal value has deviated from the fourth range by using the threshold values ​​THDA and THDB.

[0121] FIG. 8 is a diagram showing an example of a flow of a process for performing the first operation or the second operation among the processes performed by the image forming apparatus 1 according to the fourth modification of the embodiment.

[0122] The control unit 100 waits until the printing operation starts (ACT510). For example, when the control unit 100 receives a print job, it determines to start the printing operation. In this case, the print job includes information indicating the type of print medium on which the image is to be formed. In the embodiment, the printing operation refers to an operation performed by the image forming apparatus 1, including transporting the print medium and forming an image on the print medium. In the flowchart shown in FIG. 8, a description of the flow of the printing operation process performed by the image forming apparatus 1 is omitted.

[0123] When the control unit 100 determines to start the printing operation (ACT510-YES), it sets a threshold value (ACT520). More specifically, in ACT520, the control unit 100 identifies the type of print medium on which an image is to be formed based on the print job received in ACT510. The control unit 100 switches the operation mode depending on the identified type. For example, if the identified type is A4-sized plain paper in ACT520, the control unit 100 sets the operation mode of the image forming apparatus 1 to a first operation mode. For example, if the identified type is A4-sized print paper in ACT520, the control unit 100 sets the operation mode of the image forming apparatus 1 to a second operation mode. After setting the operation mode to either the first operation mode or the second operation mode, the control unit 100 sets a threshold value corresponding to the current operation mode of the image forming apparatus 1 as the threshold value for the motor signal value. For example, when the current operating mode of the image forming apparatus 1 is the first operating mode, the control unit 100 sets a threshold value THCA, which is the upper limit of the first range, and a threshold value THCB, which is the lower limit of the first range, as threshold values ​​for the motor signal value. This allows the control unit 100 to determine whether the motor signal value has deviated from a third range, which is the range from the threshold value THCA to the threshold value THCB. For example, when the current operating mode of the image forming apparatus 1 is the second operating mode, the control unit 100 sets a threshold value THDA, which is the upper limit of a fourth range, and a threshold value THDB, which is the lower limit of the fourth range, as threshold values ​​for the motor signal value. This allows the control unit 100 to determine whether the motor signal value has deviated from a fourth range, which is the range from the threshold value THDA to the threshold value THDB.

[0124] Next, the control unit 100 starts the printing operation and also starts the contact operation (ACT530). At this time, the control unit 100 controls the pressure adjustment mechanism ADC to start contacting the pressure member ADB with the outer peripheral surface of the fixing member ADA with a pressure force according to the current operation mode of the image forming apparatus 1.

[0125] Next, the control unit 100 waits until the contact operation started in ACT 530 is completed (ACT 540). The process of ACT 540 is the same as the process of ACT 130 shown in Fig. 4, and therefore a detailed description thereof will be omitted.

[0126] When the control unit 100 determines that the contact operation started in ACT540 has been completed (ACT540-YES), the control unit 100 drives the motor MT at a predetermined rotation speed to start rotating the pressing member ADB (ACT550). In other words, the control unit 100 starts driving the fixing device AD ​​in ACT550. For example, the control unit 100 drives the motor MT at 1500 rpm in ACT550.

[0127] Next, the control unit 100 controls the heater of the heating unit HT to start heating the fixing member ADA (ACT560).

[0128] Next, the control unit 100 acquires the motor signal and determines whether the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT 520 (ACT 570). The lower limit value is the smaller of the threshold values ​​set by the control unit 100 in ACT 520.

[0129] When the control unit 100 determines that the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT520 (ACT570-YES), it stores contact failure information in the storage device 1102 (ACT580).

[0130] Next, the control unit 100 performs third abnormality processing (ACT590). The third abnormality processing is processing in which either the 31st or 32nd operation is performed as an operation corresponding to the current operating mode of the image forming apparatus 1. The 31st operation is the first operation performed in the third abnormality processing by the image forming apparatus 1 operating in the first operating mode. In other words, the 31st operation is a modified example of the 11th operation according to the embodiment. The 32nd operation is the second operation performed in the third abnormality processing by the image forming apparatus 1 operating in the second operating mode. In other words, the 32nd operation is a modified example of the 12th operation according to the embodiment. The flow of the processing in which the image forming apparatus 1 performs the third abnormality processing is similar to the flow of the first abnormality processing, and therefore a detailed description thereof will be omitted. However, in the third abnormality processing, the third abnormality notification information is used instead of the first abnormality notification information in ACT340 and ACT350. The third abnormality notification information is information including, for example, contact failure information. The third abnormality notification information may include information indicating that the motor signal value falls outside the third range, instead of or in addition to the contact failure information. The third abnormality notification information may include other information in addition to either or both of these two pieces of information. After performing the third abnormality processing, the control unit 100 ends the processing of the flowchart shown in FIG. 8.

[0131] On the other hand, when the control unit 100 determines that the motor signal value of the acquired motor signal is equal to or greater than the lower limit value set in ACT 520 (ACT 570-NO), it determines whether or not the motor signal value of the acquired motor signal is greater than the upper limit value set in ACT 520 (ACT 600). The upper limit value is the larger of the threshold values ​​set by the control unit 100 in ACT 520.

[0132] When the control unit 100 determines that the motor signal value of the acquired motor signal is greater than the upper limit value set in ACT520 (ACT600-YES), it stores lubricant depletion information in the storage device 1102 (ACT610).

[0133] Next, the control unit 100 performs fourth abnormality processing (ACT620). The fourth abnormality processing is processing in which either operation 41 or operation 42 is performed as an operation corresponding to the current operating mode of the image forming apparatus 1. The 41st operation is the first operation performed in the fourth abnormality processing by the image forming apparatus 1 operating in the first operating mode. In other words, the 41st operation is a modified example of the 21st operation according to the embodiment. The 42nd operation is the second operation performed in the fourth abnormality processing by the image forming apparatus 1 operating in the second operating mode. In other words, the 42nd operation is a modified example of the 22nd operation according to the embodiment. The flow of the processing in which the image forming apparatus 1 performs the fourth abnormality processing is similar to the flow of the second abnormality processing, and therefore a detailed description thereof will be omitted. However, in the fourth abnormality processing, fourth abnormality notification information is used in ACT340 and ACT350 instead of the second abnormality notification information. The fourth abnormality notification information is information including, for example, lubricant depletion information. The fourth abnormality notification information may include information indicating that the motor signal value has fallen out of the fourth range, instead of or in addition to the lubricant depletion information. The fourth abnormality notification information may include other information in addition to either or both of these two pieces of information. After performing the fourth abnormality processing, the control unit 100 ends the processing of the flowchart shown in FIG. 8.

[0134] On the other hand, if the control unit 100 determines that the motor signal value of the acquired motor signal is equal to or less than the upper limit set in ACT520 (ACT600-NO), it determines whether the printing operation started in ACT530 has ended (ACT630). The processing in ACT630 is the same as the processing in ACT230 shown in Fig. 4, and therefore a detailed description thereof will be omitted.

[0135] If the control unit 100 determines that the printing operation started in ACT530 has not finished (ACT630-NO), it transitions to ACT570, acquires the motor signal, and again determines whether the motor signal value of the acquired motor signal is smaller than the lower limit value set in ACT520.

[0136] On the other hand, if the control unit 100 determines that the printing operation started in ACT530 has ended (ACT630-YES), it ends the processing of the flowchart shown in FIG.

[0137] As described above, the image forming apparatus 1 according to the fourth modification of the embodiment performs the first operation when the motor signal value falls outside the third range while driving the motor MT in the first operation mode, and performs the second operation when the motor signal value falls outside the fourth range while driving the motor MT in the second operation mode. This allows the image forming apparatus 1 to perform an operation in response to a malfunction occurring in the fixing device AD ​​at a desired timing.

[0138] (Other variations) In the embodiments described above or each variant of the embodiments, the difference between the first operating mode and the second operating mode may be the nip pressure of the nip formed by the fixing member ADA and the pressing member ADB in the fixing device AD.

[0139] In the above-described embodiment or each modified example of the embodiment, the difference between the first and second operation modes may be the nip pressure of the nip formed by the fixing member ADA and the pressing member ADB in the fixing device AD, because the load on the motor MT also changes depending on the nip pressure.

[0140] In the above-described embodiment or each modified example of the embodiment, the difference between the first operation mode and the second operation mode may be the target temperature of the fixing member ADA heated by the heater HT, because a change in the temperature of the fixing member ADA changes the viscosity of the lubricant, which in turn changes the load on the motor MT.

[0141] The above-described embodiments and modifications thereof may be combined in any manner.

[0142] As described above, the image forming apparatus (image forming apparatus 1 in the example described above) includes a conveying section (secondary transfer roller 23, two registration rollers 24, fixing device AD, various rollers in duplex printing device DF, etc. in the example described above), an image forming section (image forming unit 114 in the example described above), a fixing device (fixing device AD ​​in the example described above), a motor (motor MT in the example described above), and a control section (controller 100 in the example described above). The conveying section conveys the print medium. The image forming section forms a toner image of the target image on the print medium conveyed by the conveying section. The fixing device heats the print medium after the toner image has been formed by the image forming section, and fixes the toner image to the print medium as the target image. The motor drives the fixing device and outputs a signal (motor signal in the example described above) of a magnitude (motor signal value in the example described above) corresponding to the value of the drive current (drive current value in the example described above). The control unit performs a first operation when the magnitude of the signal deviates from a first range (the first range or the third range in the example described above) while driving the motor in a first operation mode, and performs a second operation when the magnitude of the signal deviates from a second range (the second range or the fourth range in the example described above) different from the first range while driving the motor in a second operation mode. This allows the image forming apparatus to perform an operation in response to a malfunction occurring in the fixing device at a desired timing.

[0143] In the image forming apparatus, the second range may be configured such that at least one of the upper limit and the lower limit is different from that of the first range.

[0144] In the image forming apparatus, a configuration may be used in which the first operating mode is an operating mode in which the motor is driven at a first rotation speed (1500 rpm in the example described above), and the second operating mode is an operating mode in which the motor is driven at a second rotation speed different from the first rotation speed (940 rpm in the example described above).

[0145] In the image forming apparatus, the fixing device may include a heating section (heating section HT in the example described above), a fixing member heated by the heating section (fixing member ADA in the example described above), and a pressing member (pressing member ADB in the example described above) that contacts the fixing member to form a nip with the fixing member, and the first operating mode is an operating mode in which the motor is driven while the pressing member and the fixing member are in contact with a first force (a pressing force of a first magnitude, i.e., 400 N in the example described above), and the second operating mode is an operating mode in which the motor M is driven while the pressing member and the fixing member are in contact with a second force (a pressing force of a second magnitude, i.e., 100 N in the example described above) that is different from the first force.

[0146] In the image forming device, a configuration may be used in which the first operation and the second operation include an operation of outputting notification information (in the example described above, each of the first to fourth abnormality notification information) including information indicating that a malfunction has occurred in the fixing device (in the example described above, contact failure information and lubricant depletion information) to an information processing device.

[0147] In the image forming apparatus, a configuration may be used in which the first operation includes an operation related to the magnitude of the signal output from the motor being outside a first range, and the second operation includes an operation related to the magnitude of the signal being outside a second range.

[0148] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention described in the claims and their equivalents.

[0149] A program for implementing the functions of any of the components of the device described above (e.g., image forming device 1) may be recorded on a computer-readable recording medium and executed by loading it into a computer system. Here, "computer system" includes hardware such as an operating system (OS) and peripheral devices. "Computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and compact disks (CDs)-ROMs, as well as storage devices such as hard disks built into computer systems. "Computer-readable recording medium" also includes devices that retain a program for a certain period of time, such as volatile memory (RAM) within a computer system that acts as a server or client when the program is transmitted over a network such as the Internet or a communication line such as a telephone line.

[0150] The above program may be transmitted from a computer system that stores the program in a storage device or the like to another computer system via a transmission medium or by transmission waves in the transmission medium. A "transmission medium" that transmits the program refers to a medium that has the function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The above program may be for realizing some of the above functions, or may be a so-called differential file (differential program) that can realize the above functions in combination with a program already recorded in the computer system. [Explanation of symbols]

[0151] 1...image forming apparatus, 11...printer section, 12...control panel, 20...intermediate transfer belt, 21...driven roller, 22...backup roller, 23...secondary transfer roller, 24...registration roller, 25...paper feed roller, 31, 32, 33, 34...image forming station, 40...belt cleaner, 41...first detection section, 42...second detection section, 43...third detection section, 100...control section, 111, 112...paper feed cassette, 114...image forming unit, 311...photosensitive drum, 312 ...electric charger, 313...exposure scanning head, 314...developing device, 315...photosensitive drum cleaner, 316...primary transfer roller, 1101...arithmetic unit, 1102...storage device, 1103...data receiving unit, 1104...image data development unit, AD...fixing device, ADA...fixing member, ADB...pressure member, ADC...pressure adjustment mechanism, DF...duplex printing device, HT...heating unit, LA, LB, LC...conveyance path, MT...motor, PA...junction, PB...branching unit, TA...manual feed tray, TB...paper output tray

Claims

1. An image forming apparatus that is communicably connected to an information processing device and forms a target image on a print medium using toner, an image forming unit that forms a toner image of a target image on the printing medium; a motor that drives the image forming unit and outputs a signal having a magnitude corresponding to a value of a driving current; A control unit; Equipped with the image forming unit further includes a fixing device that fixes the toner image formed on the print medium onto the print medium; The fixing device a fixing member heated by a heating section; a pressing member that contacts the fixing member and holds the print medium therebetween; a pressure adjusting mechanism that performs a contact operation of the pressing member to contact the fixing member; the motor; Equipped with the motor drives the pressing member; The control unit controlling the motor in either a first operating mode or a second operating mode; when the operation mode for driving the motor is the first operation mode, after the contact operation is completed, an upper limit value and a lower limit value of a first range are set as threshold values ​​for the magnitude of the signal, When the operation mode is the second operation mode, after the contact operation is completed, an upper limit value and a lower limit value of a second range different from the first range are set as the threshold values, performing a first operation when the magnitude of the signal is out of the first range while the motor is being driven in the first operation mode; performing a second operation when the magnitude of the signal falls outside the second range while driving the motor in the second operation mode; the first operation and the second operation include an operation of outputting notification information including information indicating that a malfunction has occurred in the image forming apparatus to the information processing apparatus, the first operating mode is an operating mode in which the motor is driven at a first rotation speed; the second operating mode is an operating mode in which the motor is driven at a second rotation speed; Image forming device.

2. The second range is a range in which at least one of an upper limit value and a lower limit value is different from that of the first range. The image forming apparatus according to claim 1 .

3. The first operating mode is an operating mode in which the motor is driven while the pressing member and the fixing member are in contact with each other with a first force, the second operation mode is an operation mode in which the motor is driven while the pressing member and the fixing member are in contact with each other with a second force different from the first force; The image forming apparatus according to claim 1 .

4. a conveying unit that conveys two or more types of print media; the control unit drives the motor in the operation mode corresponding to the type of the print medium, out of the first operation mode and the second operation mode; The image forming apparatus according to claim 1 .

Images