JP2021039254A - Image forming apparatus, information processing system, and information processing method - Google Patents

Abstract

To provide an image forming apparatus that can increase the accuracy in determining the life of a fixing device.SOLUTION: An image forming apparatus comprises: a fixing device 40; and a detection unit between a transfer unit and a rotatable pressure member. When a sheet is bent in a first direction, the detection unit outputs a signal to a control unit, and when the sheet is bent in a second direction opposite to the first direction, the detection unit does not output the signal. When there is input of the signal, the control unit controls the rotation speed of the pressure member to a first speed, and when there is no input of the signal, the control unit controls the rotation speed of the pressure member to a second speed slower than the first speed. When there is no input of the signal for a first time period, the control unit changes the rotation speed of the pressure member until the signal is input. When the time during which the control unit changes the rotation speed of the pressure member becomes equal to or longer than a second time period (TC2), the control unit determines that the life of the fixing device 40 is expired.SELECTED DRAWING: Figure 14

Description

The present invention relates to an image forming apparatus, an information processing system, and an information processing method.

Electrophotographic image forming apparatus is widespread. The electrophotographic image forming apparatus has, as a printing process, a step of forming a toner image corresponding to an input image on a photoconductor, a step of primary transferring a toner image on the photoconductor on a transfer belt, and a step on the transfer belt. A step of secondary transfer of the toner image to the paper and a step of heat-fixing the toner image to the paper by a fixing device are executed.

Since the fixing device is a consumable item, in order to provide users with stable and high-quality printed images, it is necessary to predict the life of the fixing device and perform maintenance such as replacing the fixing device at an appropriate time. is there.

In the life judgment of the conventional fixing device, a uniform mileage is determined from a predetermined durability evaluation result or the like, and the mileage is judged to be the arrival time of the end of the life when maintenance is required. However, in this case, even the fixing device that can still be used was judged to be at the end of its life, which was inefficient for the user's use.

Therefore, for example, as shown in Patent Document 1, two threshold values relating to the torque of the drive load of the fixing device are set, and if the torque becomes equal to or higher than the higher threshold of the two thresholds, the life of the fixing device is determined. Has been proposed. Further, Patent Document 2 discloses a technique for determining whether or not the end of the life of the fixing device has been reached based on the magnitude of the load detected by the current sensor.

JP-A-2017-138427 Japanese Unexamined Patent Publication No. 2018-155850

The sliding portion of the fixing device is worn by the sliding rotation of the fixing belt. Further, the fixing belt rotates in accordance with the pressure roller. Therefore, in order to keep the rotation speed of the pressurizing roller constant from the viewpoint of stable image formation, it is necessary to increase the rotational torque of the pressurizing roller.

However, even if the rotational torque of the pressurizing roller is increased, if the sliding load on the sliding portion of the fixing device becomes larger than the driving force transmitted from the pressurizing roller to the fixing belt, the pressurizing roller Slip occurs between the and the fixing belt, and as a result, paper slips easily occur in the nip region of the fixing device. In this case, the speed at which the paper passes through the fixing device is slower than the speed at which the paper passes through the transfer unit located on the upstream side of the fixing device. As a result, the state of the paper becomes an unfavorable bending state, which is also called "reverse loop", and the output image (image after fixing) is deteriorated.

From the above viewpoint, it is conceivable to determine in advance the torque (torque of the pressurizing roller) that is expected to cause the paper to slip, and use the torque as the reference value (threshold value) for determining the life. However, the torque when the paper slips also changes depending on the pressurization state (load) by the pressurizing roller. Therefore, it is difficult to uniquely determine the above reference value.

Therefore, in the conventional technique, as a result, the life is determined to be much earlier than the original life is reached.

The present disclosure has been made in view of the above problems, and an object of the present invention is to provide an image forming and clearing device, an information processing system, and an information processing method capable of improving the accuracy of determining the life of the fixing device. There is.

According to certain aspects of the present disclosure, the image forming apparatus has at least a fixing device for fixing an unfixed image on the recording material on the recording material, and forms an image on the recording material. The image forming apparatus transfers the image onto the recording material and conveys the recording material to the downstream side of the transfer path, and the fixing device transfers the recording material conveyed from the transfer unit to the downstream side of the transfer path. It is provided with a pressure member that can rotate in the direction of movement, a detection unit that is provided between the transfer unit and the pressure member and that detects the state of the recording material, and a control unit. When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material is bent in the second direction opposite to the first direction. In this case, the signal is not output to the control unit. The control unit controls the rotation speed of the pressurizing member to the first speed when there is a signal input, and when there is no signal input, the rotation speed of the pressurizing member is set from the first speed. Also controls to a slower second speed. When there is no signal input for the first time, the control unit fluctuates the rotation speed of the pressurizing member until the signal is input. The control unit determines that the fixing device has reached the end of its life when the time during which the rotational speed of the pressurizing member is changed exceeds the second time.

Preferably, the control unit varies the rotational speed of the pressurizing member by switching the rotational speed of the pressurizing member between a first speed and a second speed.

Preferably, the switching is performed at a predetermined cycle. The control unit determines that the fixing device has reached the end of its life when the number of times the rotation speed of the pressurizing member is switched exceeds the number of times determined by the cycle and the second time.

Preferably, the control unit determines the ratio of the number of times that the time during which the rotation speed of the pressurizing member is fluctuated is equal to or longer than the second time, out of the number of times the control unit controls to fluctuate the rotation speed of the pressurizing member. It is determined that the fixing device has reached the end of its life on the condition that it is equal to or more than the value of.

Preferably, the control unit determines the life of the fixing device every time a predetermined period elapses or every time the traveling distance of the pressurizing member increases by a predetermined distance.

Preferably, the detector includes a lever and a photosensor. When the recording material is bent in the second direction, the position of the lever is the first position, and when the recording material is bent in the first direction, the position of the lever is changed by the recording material. Move from the first position to the second position. The photo sensor outputs a signal to the control unit when the lever position is the second position.

Preferably, the control unit determines the life of the fixing device based on the time during which the rotation speed of the pressurizing member is changed, provided that the traveling distance of the pressurizing member is equal to or greater than a predetermined distance.

Preferably, the image forming apparatus is arranged inside the fixing belt and a fixing belt that forms a nip region for fixing the unfixed image against the pressure member and rotates in accordance with the rotation of the pressure member. In order to counteract the pressurization of the pressurizing member, a support member that slidably supports the fixing belt at a position facing the pressurizing member, a motor that rotates the pressurizing member, and a drive unit that drives the motor. Further prepare. The control unit acquires the torque at the time of driving the motor every time a predetermined condition is satisfied. The control unit determines the life of the fixing device based on the time during which the rotation speed of the pressurizing member is changed, on condition that the change with time of the acquired torque changes from an ascending change to a descending change.

Preferably, the predetermined condition is that the mileage of the pressurizing member is extended by a predetermined distance. The control unit acquires torque a plurality of times each time the traveling distance of the pressurizing member is extended by a predetermined distance, and calculates an average value of the torque acquired over the plurality of times. The control unit calculates the moving average value using the calculated average value and at least the previously calculated average value. The control unit determines the life of the fixing device based on the time during which the rotation speed of the pressurizing member is changed, on condition that the calculated moving average value is smaller than the previously calculated moving average value.

Preferably, the predetermined condition is that a predetermined period has passed. The control unit acquires torque a plurality of times each time a predetermined period elapses, and calculates an average value of the torque acquired over the plurality of times. The control unit calculates the moving average value using the calculated average value and at least the previously calculated average value. The control unit determines the life of the fixing device based on the time during which the rotation speed of the pressurizing member is changed, on condition that the calculated moving average value is smaller than the previously calculated moving average value.

Preferably, the control unit acquires information on the rotational speed of the pressurizing member. The control unit calculates the mileage by multiplying the rotation speed by the rotation time of the pressurizing member.

Preferably, the control unit acquires the idling torque when the paper is not passed as a torque every time the traveling distance of the pressurizing member is extended by a predetermined distance.

Preferably, the control unit acquires the idling torque when the paper is not passed as a torque every time a predetermined period elapses.

Preferably, the control unit acquires the torque detected after the image forming apparatus is warmed up or fixed on the recording material as the idling torque when the paper is not passed.

Preferably, the control unit determines that the fixing device has reached the end of its life, provided that the calculated moving average value is equal to or greater than a predetermined threshold value.

Preferably, when the control unit determines that the fixing device has reached the end of its life, the control unit permits image formation using the paper of the first paper type, and has a second basis weight smaller than that of the paper of the first paper type. Image formation using paper of the paper type of is not permitted.

Preferably, the image forming apparatus further comprises an operation panel. When the control unit determines that the fixing device has reached the end of its life, the control unit displays a predetermined image on the operation panel.

Preferably, the control unit shortens the second time on condition that the change with time of the acquired torque changes from an ascending change to a descending change.

Preferably, the control unit increases the rotational speed of the pressurizing member as the time for varying the rotational speed of the pressurizing member increases.

Preferably, the control unit increases the load of the pressurizing member on the support member as the time for varying the rotational speed of the pressurizing member increases.

According to another aspect of the present disclosure, the information processing system has at least a fixing device for fixing an unfixed image on the recording material on the recording material, and an image forming device for forming an image on the recording material, and information. It is equipped with a processing device. The image forming apparatus transfers the image onto the recording material and conveys the recording material to the downstream side of the transfer path, and the fixing device transfers the recording material conveyed from the transfer unit to the downstream side of the transfer path. A pressurizing member that can rotate in the direction of rotation, a fixing belt that forms a nip region for fixing an unfixed image against the pressurizing member, and rotates in accordance with the rotation of the pressurizing member, and a transfer unit. It is provided between the pressurizing member and includes a detection unit for detecting the state of the recording material and a control unit. When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material is bent in the second direction opposite to the first direction. In this case, the signal is not output to the control unit. The control unit controls the rotation speed of the pressurizing member to the first speed when there is a signal input, and when there is no signal input, the rotation speed of the pressurizing member is set from the first speed. Also controls to a slower second speed. When there is no signal input for the first time, the control unit fluctuates the rotation speed of the pressurizing member until the signal is input. The information processing device acquires information on the time during which the rotational speed of the pressurizing member is fluctuating from the control unit. The information processing device determines that the fixing device has reached the end of its life when the time during which the rotational speed of the pressurizing member is changed exceeds the second time.

According to still another aspect of the present disclosure, the information processing method is performed in an image forming apparatus having at least a fixing device for fixing an unfixed image on the recording material on the recording material and forming an image on the recording material. .. The image forming apparatus transfers the image onto the recording material and conveys the recording material to the downstream side of the transfer path, and the fixing device transfers the recording material conveyed from the transfer unit to the downstream side of the transfer path. A pressurizing member that can rotate in the direction of rotation, a fixing belt that forms a nip region for fixing an unfixed image against the pressurizing member, and rotates in accordance with the rotation of the pressurizing member, and a transfer unit. It includes a detection unit provided between the pressurizing member and detecting the state of the recording material, and a control unit. When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material is bent in the second direction opposite to the first direction. In this case, the signal is not output to the control unit. The information processing method includes a step in which the control unit controls the rotation speed of the pressurizing member to the first speed when the control unit has a signal input, and a control unit when the control unit does not have a signal input. However, there is a step of controlling the rotation speed of the pressurizing member to a second speed slower than the first speed, and when the control unit does not have a signal input for the first time, the control unit has a signal input. When the step of changing the rotation speed of the pressurizing member and the time of changing the rotation speed of the pressurizing member become the second time or more, the control unit determines that the fixing device has reached the end of its life. With steps.

According to the present disclosure, the accuracy of determining the life of the fixing device can be improved.

It is a figure which shows an example of the apparatus configuration of an image forming apparatus. It is a block diagram for demonstrating the hardware structure of an image forming apparatus. It is a figure for demonstrating the hardware structure of the fixing device. It is a block diagram for demonstrating the torque detection performed in a fixing device. It is an enlarged view of the main part of an image forming apparatus. It is the figure which showed the state which the paper is not looping. It is a figure which showed the state which the paper is looping. It is a figure for demonstrating the reverse loop state. It is a figure explaining how to make the rotation speed of a pressure roller fluctuate. It is a functional block diagram which showed the functional structure of a control device. It is a flow chart which showed the flow of processing executed by a control device. It is a flow chart which showed the detailed flow of the process of step S510 of FIG. It is a flow chart which showed the detailed flow of the process of step S540 of FIG. It is a flow chart which showed the flow of the life determination process. It is a flow chart which showed the flow of the life determination process of the fixing device 40 when a predetermined value is used. It is a flow chart which showed the flow of the life determination processing when the number of prints and the mileage are added to the life determination. It is the figure which showed the example of the warning screen displayed on the operation panel. It is a functional block diagram which showed the functional structure of a control device. It is a figure which showed the time-dependent change of a moving average torque. It is a flow diagram for demonstrating the flow of processing executed by an image forming apparatus. It is a flow chart for demonstrating the details of the process of step S2 of FIG. It is a flow chart for demonstrating the details of the process of step S27 of FIG. It is a figure which showed the time-dependent change of a moving average torque. In this modification, it is a flow diagram for demonstrating the details of the process of step S27 of FIG. It is a figure which showed the time-dependent change of a moving average torque. It is a flow chart for demonstrating the details of the process of step S27 of FIG. It is a figure which showed the time-dependent change of a moving average torque. It is a flow chart for demonstrating the details of the process of step S27 of FIG. It is a functional block diagram which showed the functional structure of a control device. It is a figure which showed the time-dependent change of a moving average torque. It is a flow chart for demonstrating the details of the process of step S2 of FIG. It is a flow chart for demonstrating the details of the process of step S27A of FIG. It is a flow diagram for demonstrating the flow of processing executed by an image forming apparatus. It is a figure which showed the network structure of an information processing system.

The image processing apparatus according to the embodiment will be described below with reference to the drawings. When the number, quantity, etc. are referred to in the embodiments described below, the scope of the present disclosure is not necessarily limited to the number, quantity, etc., unless otherwise specified. The same parts and equivalent parts may be given the same reference number, and duplicate explanations may not be repeated.

In the drawings, some parts are not shown according to the actual dimensional ratios, and some parts are shown by changing the ratios so that the structure becomes clear in order to facilitate understanding of the structure. In addition, each embodiment and each modification described below may be selectively combined as appropriate.

Further, although the image forming apparatus as a color printer will be described below, the image forming apparatus is not limited to the color printer. For example, the image forming apparatus may be a monochrome printer, a fax machine, or a monochrome printer, a color printer, and a multi-function peripheral (MFP).

[Embodiment 1]
<A. Overall configuration>
FIG. 1 is a diagram showing an example of an apparatus configuration of the image forming apparatus 100.

The image forming apparatus 100 includes an imaging unit 1Y, 1M, 1C, 1K, an intermediate transfer belt 30 (material to be transferred), a primary transfer roller 31, a secondary transfer roller 33, a cassette 37, a fixing device 40, and the like. A cleaning blade 53 and a control device 101 are provided.

The image forming apparatus 100 includes a toner bottle 15Y for supplying yellow (Y) toner, a toner bottle 15M for supplying magenta (M) toner, a toner bottle 15C for supplying cyan (C) toner, and black. A toner bottle 15B for supplying the toner of (BK) can be attached. The imaging unit 1Y receives the toner supply from the toner bottle 15Y and forms a yellow (Y) toner image. The imaging unit 1M receives the toner supply from the toner bottle 15M to form a magenta (M) toner image. The imaging unit 1C receives the toner supply from the toner bottle 15C and forms a toner image of cyan (C). The imaging unit 1K receives the toner supply from the toner bottle 15K and forms a black (BK) toner image. The imaging units 1Y, 1M, 1C, and 1K are arranged in order along the rotation direction of the intermediate transfer belt 30, respectively.

The imaging units 1Y, 1M, 1C, and 1K each include a photoconductor 10, a charging roller 11, an exposure unit 12, a developing device 13, and a cleaning blade 17. The imaging units 1Y, 1M, 1C, and 1K are removable from the main body of the image forming apparatus 100.

The photoconductor 10 is an image carrier that supports a toner image. As an example, as the photoconductor 10, a photoconductor drum having a photosensitizing layer formed on its surface is used.

The charging roller 11 uniformly charges the surface of the photoconductor 10. The exposure unit 12 irradiates the photoconductor 10 with a laser in response to a control signal from the control device 101, and exposes the surface of the photoconductor 10 according to a designated image pattern. As a result, an electrostatic latent image corresponding to the input image is formed on the photoconductor 10.

The developer 13 develops an electrostatic latent image using a developer containing toner, carriers, and an external additive. The developer is supplied from the toner bottle. The developer 13 includes a developing roller 14. The developer 13 applies a development bias to the developing roller 14 to attach toner to the surface of the developing roller 14. The developing device 13 rotates the developing roller 14 to transfer toner from the developing roller 14 to the photoconductor 10. As a result, a toner image corresponding to the electrostatic latent image is developed on the surface of the photoconductor 10.

The photoconductor 10 and the intermediate transfer belt 30 are in contact with each other at a portion where the primary transfer roller 31 is provided. A predetermined transfer bias is applied to the contact portion, and the toner image developed on the photoconductor 10 is transferred to the intermediate transfer belt 30 by the transfer bias. At this time, the yellow (Y) toner image, the magenta (M) toner image, the cyan (C), and the black (BK) toner images are sequentially superimposed and transferred to the intermediate transfer belt 30. As a result, a color toner image is formed on the intermediate transfer belt 30.

The cleaning blade 17 is pressed against the photoconductor 10 and collects the toner remaining on the surface of the photoconductor 10 after transfer to the intermediate transfer belt 30.

The cassette 37 is provided, for example, in the lower part of the image forming apparatus 100. Paper S (transfer medium) as a recording material is set in the cassette 37. The paper S is fed from the cassette 37 one by one to the secondary transfer roller 33. The secondary transfer roller 33 transfers the toner image transferred to the intermediate transfer belt 30 to the paper S. By synchronizing the timing of feeding and transporting the paper S with the position of the toner image on the intermediate transfer belt 30, the toner image is transferred to an appropriate position on the paper S. After that, the secondary transfer roller 33 conveys the paper S to the fixing device 40 at a predetermined speed. The secondary transfer roller 33 is rotationally driven by a drive device (not shown).

The fixing device 40 fixes the unfixed image on the paper S on the paper. Specifically, the fixing device 40 melts the toner image on the paper S passing through the fixing device 40, and fixes the toner image on the paper S. After that, the paper S is discharged to the tray 48. The specific configuration of the fixing device 40 will be described later.

The cleaning blade 53 is pressed against the intermediate transfer belt 30 to collect the toner remaining on the intermediate transfer belt 30 after the toner image is transferred. The toner is conveyed by a conveying screw (not shown) and collected in a waste toner container (not shown).

The control device 101 controls the operation of the image forming device 100. The control device 101 controls, for example, a motor for controlling the rotation of the photoconductor 10, a motor for controlling the rotation of the primary transfer roller 31, and the like. Further, the control device 101 controls the operation of the fixing device 40. The motor is driven by, for example, PWM (Pulse Width Modulation) control.

As described above, the image forming apparatus 100 has at least a fixing device 40 for fixing the unfixed image G on the paper S (recording material) on the paper S, and forms an image on the paper S.

FIG. 2 is a block diagram for explaining the hardware configuration of the image forming apparatus 100.
The image forming apparatus 100 includes at least a control device (control unit) 101, an operation panel 102, a fixing device 40, and a sensor device (detection unit) 60.

The operation panel 102 includes a touch screen 120. The touch screen 120 is composed of a display 122 and a touch panel 121 arranged so as to be superimposed on the display 122.

The control device 101 includes a CPU (Central Processing Unit) 131, which is an example of a processor that executes a program, a ROM (Read Only Memory) 132 that stores data non-volatilely, and a RAM (Random Access) that stores data volatilely. It has a Memory) 133, a flash memory 134, and a communication IF 135. The control device 101 can communicate with the operation panel 102 by the communication IF 135.

The flash memory 134 is a non-volatile semiconductor memory. The flash memory 134 stores an operating system executed by the CPU 131, various programs, various contents, and data. Further, the flash memory 134 volatilely stores various data such as data generated by the image forming apparatus 100 and data acquired from an external device of the image forming apparatus 100.

The sensor device 60 includes a lever 61 and a photo sensor 62. The sensor device 60 is provided between the secondary transfer roller 33 as a transfer device (transfer unit) for transferring an image to the paper S and the fixing device 40 (specifically, the pressurizing roller 408 of the fixing device 40). And the state of the paper S is detected. Specifically, the sensor device 60 detects whether or not the paper S is bent in a predetermined direction (first direction). Hereinafter, the state in which the paper S is bent in a predetermined direction is also referred to as a “loop state” or a “normal loop state”. Although the details will be described later, the loop state is the bending of the paper S that occurs in the normal state.

When the paper S is in the loop state, the sensor device 60 transmits a predetermined signal (on signal) to the control device 101. The sensor device 60 does not transmit a predetermined signal (on signal) to the control device 101 when the paper S is bent in the direction opposite to the predetermined direction (second direction). .. The predetermined signal is also referred to as a "detection signal".

Further, in the following, the state in which the paper S is bent in the direction opposite to the predetermined direction is also referred to as a “reverse loop state”. Although the details will be described later, the reverse loop state is the bending of the paper S in the direction opposite to the loop state, and is the bending of the paper S that occurs when an abnormality occurs.

The details of the sensor device 60, the loop state, and the reverse loop state will be described later.

The control device 101 determines at least whether or not the state of the paper S is the "loop state" based on the presence or absence of the signal output from the sensor device 60. More specifically, the control device 101 also determines whether or not the state of the paper S is the "reverse loop state" by the process described later.

<B. Fixing device>
FIG. 3 is a diagram for explaining the hardware configuration of the fixing device 40.

The fixing device 40 typically includes a heating member 401, a fixing belt 402, a fixing member (support member) 490, a pressure roller (pressurizing member) 408, a motor 409, and a drive device (drive unit). It is equipped with 410.

The fixing member 490 is arranged inside the fixing belt 402, and slidably supports the fixing belt 402 at a position facing the pressure roller 408 in order to counter the pressure of the pressure roller 408. Specifically, the fixing member 490 includes a holding member 403, a nip forming member 405, a sliding sheet 406, and a curvature imparting member 407. The nip forming member 405 has a connecting shaft 454.

The heating member 401 is a heat source for heating the fixing belt 402. The heating member 401 includes a halogen heater 451 and a housing 452. The halogen heater 451 is installed in the housing 452. The outer surface of the housing 452 is in contact with the fixing belt 402. The heating member 401 transfers the heat generated by the halogen heater 451 to the fixing belt 402 via the housing 452.

In the case of this example, the halogen heater 451 is composed of two heaters having different heat generation regions. The housing 452 is a pipe made of aluminum or stainless steel and having a thickness of about 0.2 mm to 0.5 mm. The inner peripheral surface of the housing 452 is painted black in order to increase the absorption of light generated from the halogen heater 451. Further, the outer peripheral surface of the housing 452 is coated with a fluorine-based coating to prevent stains.

In this example, a configuration in which the heating member 401 does not rotate even if the fixing belt 402 rotates is given as an example. However, the present invention is not limited to this, and the heating member 401 may have a configuration in which the heating member 401 is driven to rotate according to the rotation of the fixing belt 402.

The fixing belt 402 is an endless belt. The fixing belt 402 forms a nip region for fixing the unfixed image G against the pressure roller 408, and rotates in accordance with the rotation of the pressure roller 408. Specifically, the fixing belt 402 is supported by the fixing member 490 at a position facing the pressure roller 408, and the unfixed image is fixed on the paper S between the fixing belt 402 and the pressure roller 408. Specifically, the fixing belt 402 is supported by the nip forming member 405 and the heating member 401 in a tensioned state, and rotates in accordance with the rotation of the pressure roller 408.

The fixing belt 402 has a base layer having a thickness of about 50 μm to 100 μm made of polyimide resin (PI) or nickel, an elastic layer made of silicon rubber having a thickness of about 100 μm to 300 μm, and a thickness of about 10 μm to 50 μm. It consists of a fluorine-based release layer.

Specifically, the fixing belt 402 has an elastic layer on the base layer and a release layer on the elastic layer. The base layer comes into contact with the outer peripheral surface of the housing 452 of the heating member 401. The release layer comes into contact with the surface of the pressure roller 408 and the paper S. More specifically, the release layer comes into contact with the unfixed image G on the paper S.

The holding member 403 holds the nip forming member 405. The holding member 403 is made of a U-shaped sheet metal having a thickness of about 2 mm. The holding member 403 is drilled at a position corresponding to the connecting shaft 454 in order to fit the connecting shaft 454 of the nip forming member 405.

The nip forming member 405 forms a nip region with the pressurizing roller 408. The nip forming member 405 is made of a resin such as LCP (Liquid Crystal Plastic). Further, the connecting shaft 454 of the nip forming member 405 projects to the side opposite to the nip region. The circumference of the nip forming member 405 is wound around the sliding sheet 406.

The sliding sheet 406 as a sliding member is made of a glass cloth sheet or a PTFE (polytetrafluoroethylene) sheet covered with a fluororesin having excellent slidability. By sandwiching the sliding sheet 406 between the nip forming member 405 and the fixing belt 402 and rotating the fixing belt 402, the resistance during sliding can be reduced. As a result, the fixing belt 402 can be rotated stably.

Further, the sliding sheet 406 has irregularities having a depth of about 50 μm to 200 μm on the surface on the side in contact with the fixing belt 402. As a result, the contact area with the fixing belt 402 can be reduced, so that the resistance during sliding can be reduced. Further, by applying grease as a lubricant between the fixing belt 402 and the sliding sheet 406, the resistance during sliding is reduced.

Further, when the sliding sheet 406 is wound around the nip forming member 405 and fixed, in order to fix the position of the sliding sheet 406, it corresponds to the connecting shaft 454 between the upstream side and the downstream side of the sliding sheet 406. There is a hole in. The connecting shaft 454 penetrates the through hole of the sliding sheet 406 and the through hole of the holding member 403. Further, by applying the pressing force by the pressure roller 408 in this state, the sliding sheet 406 is sandwiched between the nip forming member 405 and the holding member 403 by the pressing force, and the position of the sliding sheet 406 is maintained. To.

The curvature imparting member 407 imparts curvature to a portion of the fixing belt 402 that has passed through the nip region. The curvature imparting member 407 is made of a resin such as LCP, like the nip forming member 405.

The pressurizing roller 408 is rotated by the motor 409 in the fixing device 40 in the direction of transporting the paper S (specifically, the paper S conveyed from the secondary transfer roller 33) to the downstream side of the transfer path. The pressure roller 408 can rotate in the forward direction (direction of arrow Q in the figure) in which the paper S is conveyed from the upstream side to the downstream side of the transfer path, and in the opposite direction. When the pressure roller 408 rotates in the positive direction, the fixing belt 402 also rotates in the positive direction (direction of arrow R in the figure). In FIG. 3, as shown by the arrow 15, since the paper S is conveyed from the bottom to the top, the upstream side is the lower position and the downstream side is the upper position.

Although the details will be described later, the pressurizing roller 408 can rotate at a rotation speed VH higher than the reference speed and a rotation speed VL lower than the reference speed. The rotation speed is determined by the number of rotations. The rotation speed command is sent from the control device 101 to the drive device 410. As an example, the rotation speed VH is 3% faster than the reference speed, and the rotation speed VL is 3% slower than the reference speed.

The pressure roller 408 is made of silicon rubber having a diameter of about 20 mm to 40 mm. Further, the surface of the silicone rubber is covered with a fluorine-based tube in order to improve the releasability.

The drive device 410 rotates the motor 409. The drive device 410 rotates the motor 409 in the forward direction and the reverse direction in response to a command from the control device 101.

The motor 409 rotates the pressurizing roller 408 in the forward direction (direction of arrow Q) and the reverse direction based on the command from the drive device 410. The motor 409 is connected to the rotating shaft of the pressurizing roller 408 with a gear (not shown) interposed therebetween.

Based on the instruction from the control device 101, the pressure roller 408 is in contact with the fixing belt 402 (position shown in FIG. 3) and at a predetermined position separated from the fixing belt 402 by a moving mechanism (not shown) (for example, FIG. 3). It is possible to move between the position of the pressurizing roller 408 and the position to the right of the position of the pressure roller 408. That is, the pressure roller 408 moves between the position where the fixing belt 402 is rotated (the position shown in FIG. 3) and the position where the fixing belt 402 is not rotated.

Specifically, at the time of image formation, the pressure roller 408 moves to a position in contact with the fixing belt 402 as shown in FIG. In this state, the fixing member 490 is pressurized by the pressure roller 408 at a position supporting the fixing belt 402. On the other hand, at the time of non-image formation, the pressure roller 408 is separated from the fixing belt 402.

At least after the image forming apparatus 100 is warmed up and after being fixed on the recording material, the pressure roller 408 is in contact with the fixing belt 402 as shown in FIG. After the image forming apparatus 100 is warmed up and after being fixed on the paper S, the paper S does not pass through the fixing device 40. That is, the paper is not passed.

FIG. 4 is a block diagram for explaining the torque detection executed in the fixing device 40.

The fixing device 40 includes a motor 409, a driving device 410, and a rotary encoder 420. The drive device 410 includes a motor control device 411 as a lower control device and a driver 412 which is an electronic circuit. The driver 412 includes a torque detection unit 413.

The drive device 410 drives the motor 409 so as to keep the rotation speed of the pressurizing roller 408 constant based on a command (rotation speed command) from the control device 101 as a higher-level control device.

The motor 409 is typically a three-phase AC motor. Rotation is performed by applying a voltage (V) between the input terminals of the three phases (U layer, V layer, W layer). As the motor 409, a control motor such as a servo motor can also be used.

The motor control device 411 receives a rotation speed command from the control device 101. When the motor control device 411 receives the rotation speed command, the motor control device 411 performs feedback control so that the rotation speed of the motor 409 becomes the rotation speed of the received rotation speed command (hereinafter, also referred to as "command rotation speed").

When the motor control device 411 receives the rotation speed command, the motor control device 411 sends a torque command to the driver 412 in response to the rotation speed command.

The driver 412 controls the switching operation of the internal switching element in order to apply a voltage based on the received torque command to each input terminal. As a result, a current flows from the driver 412 to the motor 409. The motor 409 is rotated by the current. The driver 412 acquires the current value of the current passed through the motor 409 from the sensor (not shown).

The rotary encoder 420 detects the rotation speed of the motor 409. The detected rotation speed (hereinafter, also referred to as “actual rotation speed”) is fed back to the motor control device 411. Further, the actual rotation speed is notified to the driver 412.

The motor control device 411 calculates the difference between the command rotation speed and the actual rotation speed. The motor control device 411 controls the torque command output to the driver 412 so that the difference approaches zero.

The torque detection unit 413 detects the torque Tq (load torque) of the motor 409 based on the actual rotation speed acquired from the rotary encoder 420 and the current value detected by the sensor. Specifically, the driver 412 periodically calculates the torque Tq by dividing the product of the applied voltage (V) and the detected current value (I) by the actual rotation speed.

Each time the predetermined condition is satisfied, the drive device 410 notifies the control device 101 of the detected torque Tq when the predetermined condition is satisfied. It should be noted that whether or not the predetermined conditions are satisfied is typically determined by the control device 101.

With such a configuration, the control device 101 can acquire the torque Tq detected by the drive device 410 from the drive device 410 every time a predetermined condition is satisfied. Specifically, the control device 101 can acquire the torque Tq detected by the drive device 410 when a predetermined condition is satisfied.

<C. State control of paper S>
Hereinafter, the state of the paper S between the secondary transfer roller 33 and the fixing device 40 and the control of the rotation speed of the pressure roller 408 according to the state of the paper S will be described.

(C1. Device configuration)
FIG. 5 is an enlarged view of a main part of the image forming apparatus 100.

The image forming apparatus 100 includes a fixing apparatus 40, a secondary transfer roller 33, an intermediate transfer belt 30, a sensor device 60, a separation claw 71, and a paper passing guide 72, 73, 74, 75. The sensor device 60 includes the lever 61 described above, a rotating shaft 611, and a photo sensor 62 (see FIG. 2).

The separation claw 71 serves to separate the paper S from the intermediate transfer belt 30 and to convey the paper S to the fixing device 40 side when the paper S does not separate from the intermediate transfer belt 30.

The paper passing guides 72 to 75 serve to guide the paper S to the fixing device 40. The paper passing guide 72 is provided on the upper portion (fixing device 40 side) of the separation claw 71. The paper passing guide 73 is provided above the paper passing guide 72 and below the fixing belt 402 of the fixing device 40. The paper passing guide 74 is provided at a position facing the paper passing guide 72 and above the secondary transfer roller 33. The paper passing guide 75 is provided at the lower part of the pressurizing roller 408 and at the upper part of the paper passing guide 74. The paper passing guide 75 serves to convey the paper S to the nip region of the fixing device 40.

The areas R1, R2, and R3 are areas where the printed surface of the paper S may come into contact when the paper S cannot be properly conveyed (for example, when the paper S is in a reverse loop state). When the print surface of the paper S comes into contact with the areas R1, R2, and R3, the image is rubbed.

The lever 61 of the sensor device 60 rotates about the rotation shaft 611. Specifically, the contact of the paper S causes the lever 61 to rotate clockwise by a predetermined angle from the illustrated position (hereinafter, also referred to as “default position”). Hereinafter, the position of the lever 61 when rotated by a predetermined angle is also referred to as an “end point position” for convenience of explanation. The lever 61 returns to the default position when the contact with the paper S is lost. In this way, the lever 61 takes a different posture depending on the presence or absence of contact with the paper S.

The photo sensor 62 (not shown) does not output a detection signal to the control device 101 when the lever 61 is in the default position. On the other hand, the photo sensor 62 outputs a detection signal to the control device 101 when the lever 61 is at the end point position. That is, when the lever 61 is at the end point position, it is in the on state (state in which a signal is output), and when the lever 61 is in the default position (position shown in FIG. 5), it is in the off state (state in which no signal is output). It becomes.

(C2. Loop control)
The loop control is started just before the paper S enters the fixing device 40. Until the loop control is started, the pressurizing roller 408 continues to rotate at the speed VH on the high speed side described above. Hereinafter, the loop control is also referred to as “normal loop control” in order to distinguish it from the reverse loop control described later. The loop state is also referred to as a "normal loop state" in order to distinguish it from the reverse loop state.

FIG. 6 is a diagram showing a state in which the paper S is not looped.
The paper S is in a substantially straight state between the secondary transfer roller 33 and the fixing device 40. In this state, the forward loop control has already started. The straight state is a state in which there is no bending between the contact region between the secondary transfer roller 33 and the intermediate transfer belt 30 and the nip region of the fixing device 40.

In the state (posture) of the paper S shown in FIG. 6, the paper S does not come into contact with the lever 61 of the sensor device 60. Therefore, the lever 61 does not rotate clockwise. That is, the lever 61 maintains the default position. Therefore, the photo sensor 62 (see FIG. 2) does not output the detection signal to the control device 101.

In this case, the paper S is in a slightly pulled state. Therefore, the control device 101 switches the rotation speed of the pressurizing roller 408 from the speed VH on the high speed side to the speed VL on the low speed side. As a result, the pulling state of the paper S is relaxed.

FIG. 7 is a diagram showing a state in which the paper S is looped.
The central portion of the paper S is bent in the positive direction of the X-axis in the figure between the secondary transfer roller 33 and the fixing device 40. That is, the paper S is in a curved state. Specifically, the paper S is loose. More specifically, the paper S is in a state in which the central portion of the paper S is displaced in the direction of the sensor device 60 as compared with the state in which the paper S is straight. Hereinafter, the state in which the paper S is bent in the direction as shown in FIG. 7 is also referred to as a “normal loop state” for convenience of explanation.

As shown in FIG. 7, when the bending of the paper S becomes large to some extent, the paper S comes into contact with the lever 61 of the sensor device 60. As a result, the lever 61 rotates clockwise. As a result, the lever 61 moves from the default position to the end point position. When the lever 61 reaches the end point position, the photo sensor 62 continues to output the detection signal to the control device 101. In this case, the paper S is in a loosened state.

When the control device 101 receives a signal input from the photosensor 62 when the rotation speed of the pressurizing roller 408 is the speed VL on the low speed side, the rotation speed of the pressurizing roller 408 is changed from the low speed VL to the high speed side. Switch to speed VH. Thereby, the slack of the paper S can be eliminated.

As described above, the control device 101 adjusts the rotation speed of the pressurizing roller 408 according to the presence or absence of the detection signal from the sensor device 60. By such speed control, the paper S can be rushed into the fixing device 40 in an appropriate state.

(C3. Reverse loop control)
Due to the above-mentioned forward loop control, the reverse loop state is unlikely to occur for paper having a predetermined basis weight or more (for example, paper having a basis weight of plain paper or more). That is, paper having a rigidity equal to or higher than a predetermined value is unlikely to be in a reverse loop state. However, paper having a small basis weight such as thin paper is more likely to have a reverse loop state than paper having a large basis weight.

FIG. 8 is a diagram for explaining a reverse loop state.
When the paper S moves in the direction of the arrow W, it enters a reverse loop state. Specifically, the central portion of the paper S bends between the secondary transfer roller 33 and the fixing device 40 in the negative direction of the X-axis in the drawing. That is, the paper S is in a state in which the bending direction is opposite to the bending state in FIG. 7. Specifically, the paper S is in a state in which the central portion of the paper S is displaced in the direction of the paper passing guides 72 and 73 as compared with the state in which the paper S is straight.

In this state, since the lever 61 of the sensor device 60 maintains the default position, the photo sensor 62 does not output the detection signal to the control device 101. Therefore, the rotation speed of the pressurizing roller 408 maintains the speed VL on the low speed side.

That is, the control device 101 determines that the paper S is slightly pulled even though the paper S is loose. When the rotation speed of the pressurizing roller 408 is maintained at the speed VL on the low speed side, the deflection becomes large. That is, the slack of the paper S increases.

When the rear end portion of the paper S passes through the secondary transfer roller 33 in such a state, the rear end portion of the paper S flutters. As a result, rubbing of the image occurs and the edge portion at the rear end of the paper S becomes dirty.

In order to eliminate the occurrence of such a situation, the control device 101 performs the reverse loop control described below.

When the input of the detection signal does not reach the predetermined time set for the start of control (hereinafter, also referred to as “set time TC1”), the control device 101 rotates the pressurizing roller 408 until the detection signal is input. To fluctuate. Typically, the control device 101 switches the rotational speed of the pressurizing roller 408 between speed VH and speed VL. For example, the control device 101 switches the rotation speed at a predetermined cycle.

FIG. 9 is a diagram illustrating how to change the rotation speed of the pressure roller 408.
When the set time TC1 elapses after the detection signal is no longer input, the control device 101 periodically switches the rotation speed of the pressurizing roller 408. That is, the control device 101 periodically switches the rotation speed of the pressurizing roller 408 when the set time TC1 elapses after the rotation speed reaches the speed VL. Specifically, when the set time TC1 elapses, the control device 101 sets the rotation speed to the speed VH during the time TD. Further, the control device 101 sets the rotation speed to the speed VH over the time TD, and then sets the rotation speed to the speed VL during the time TE. After that, the rotation speed is similarly switched between the speed VH and the speed VL. The time TD and the time TE are typically the same time.

By controlling the rotation speed of the pressure roller 408 to be changed in this way, it is possible to alternately give the paper S a pulling action and a loosening action. This makes it possible to return the reverse loop state of the paper S to the normal loop state.

When the state of the paper S becomes the normal loop state, the position of the lever 61 becomes the end point position, so that the control device 101 receives the detection signal. After that, the above-mentioned positive loop control is executed.

(C4. Lifespan judgment)
The life determination of the fixing device 40 will be described. In this example, the control device 101 uses the control result of the reverse loop control to determine whether or not the life of the fixing device 40 has reached the end.

In the control device 101, the time during which the rotation speed of the pressurizing roller 408 is changed (hereinafter, referred to as “variation time Tz”) is a predetermined time set for life determination (hereinafter, also referred to as “set time TC2”). ), It is determined that the fixing device 40 has reached the end of its life. In the case of this example, the time for varying the rotation speed of the pressurizing roller 408 is the sum of the time obtained by multiplying the time TD by an integer and the time obtained by multiplying the time TE by an integer.

Further, in the example of FIG. 9, since the rotation speed of the pressure roller 408 fluctuates periodically, the fluctuation time Tz is also proportional to the number of times the rotation speed of the pressure roller 408 is switched. Therefore, the control device 101 determines that the fixing device 40 has reached the end of its life when the number of times the rotation speed of the pressurizing roller 408 is switched becomes equal to or greater than the number of times determined by the fluctuation cycle f and the set time TC2. May be good. The period f is the reciprocal of the sum of the time TD and the time TE (f = 1 / (TD + TE)).

Typically, when the number of rotation speed switching is larger than the value obtained by dividing the set time TC2 by the period f (that is, TC2 / f), the control device 101 has a life of the fixing device 40. Is determined to be. When the value (TC2 / f) obtained by dividing the set time TC2 by the period f becomes a small number, the control device 101 determines that the number of times the rotation speed is switched is the first minority of the value. When it is larger than the value rounded up (integer value), it may be determined that the fixing device 40 has reached the end of its life.

From the viewpoint of improving the accuracy of the life determination, the following life determination may be performed.
The ratio of the number of times that the fluctuation time Tz becomes the set time TC2 or more to the number of times that the control device 101 controls to change the rotation speed of the pressurizing roller 408 is a predetermined value TR (for example, 30%) or more. On the condition that the fixing device 40 has reached the end of its life, it may be determined. The fluctuation time Tz may accidentally exceed the time TC2 only once. In this case, it may not be preferable to determine the life of the fixing device 40. Therefore, the accuracy of the life determination can be improved by performing the determination using the ratio as described above.

Further, the control device 101 may determine the life of the fixing device 40 every time a predetermined period elapses or every time the mileage of the pressurizing roller 408 is extended by a predetermined distance. That is, the control device 101 does not always determine the life of the fixing device 40, but may determine the life each time a predetermined condition is satisfied.

In the second to fourth embodiments described later, the control device 101 determines the life of the fixing device 40 each time the predetermined conditions are satisfied.

(Modification example)
In the above, when the time (variation time Tz) in which the rotation speed of the pressurizing roller 408 is changed becomes equal to or longer than the predetermined time (set time TC2) set for the life determination, the control device 101 It is determined that the fixing device 40 has reached the end of its life. Specifically, the fluctuation time Tz was defined as the time required for one reverse loop control (the sum of the time obtained by multiplying the time TD by an integer and the time obtained by multiplying the time TE by an integer (see FIG. 9)). However, it is not limited to this.

For example, the fluctuation time Tz is regarded as the cumulative value of the time required for each reverse loop control (hereinafter, also referred to as "cumulative time"), and when the cumulative time exceeds the set time Tc, the fixing device 40 has a life. The control device 101 may be configured so as to determine that. That is, the control device 101 is not the time required for the reverse loop control for one sheet S (hereinafter, also referred to as "element time"), but the time required for the reverse loop control for each of the plurality of sheets S (that is,). , Cumulative time), it may be determined whether or not the fixing device 40 has reached the end of its life.

The time required for the reverse loop control is accumulated and the cumulative time is calculated based on the accumulated time by the control device 101.

<D. Functional configuration>
FIG. 10 is a functional block diagram showing the functional configuration of the control device 101.

The image forming apparatus 100 includes a control device 101, a driving device 410, an operation panel 102, and a sensor device 60.

The control device 101 includes a rotation speed control unit 150, a life determination unit 154, a display control unit 155, and a communication control unit 156.

The rotation speed control unit 150 controls the rotation speed of the pressurizing roller 408. Specifically, the rotation speed control unit 150 controls the rotation speed of the pressurizing roller 408 by sending a speed command to the motor control device 411 (see FIG. 4) of the drive device 410.

Specifically, the rotation speed control unit 150 receives a detection signal from the sensor device 60. Specifically, the rotation speed control unit 150 receives the detection signal output from the photo sensor 62 based on the fact that the lever 61 moves from the default position to the end point position due to the contact of the paper S. The rotation speed control unit 150 controls the rotation speed of the pressurizing roller 408 depending on whether or not a detection signal is received.

For example, during execution of the forward loop control, the rotation speed control unit 150 controls the rotation speed of the pressurizing roller 408 to the speed VH or the speed VL based on the presence or absence of reception of the detection signal. When a reverse loop state (see FIG. 8) occurs, the rotation speed control unit 150 changes the rotation speed of the pressurizing roller 408 until a detection signal is input. In this example, the rotation speed control unit 150 switches the rotation speed of the pressurizing roller 408 between the speed VH and the speed VL.

The rotation speed control unit 150 notifies the life determination unit 154 of information on the fluctuation time Tz that fluctuates the rotation speed of the pressurizing roller 408 when the reverse loop state is reached. The rotation speed control unit 150 may notify the life determination unit 154 of the information on the number of fluctuations instead of the information on the fluctuation time Tz.

The life determination unit 154 determines whether or not the fixing device 40 has reached the end of its life. Specifically, the life determination unit 154 determines whether or not the life of the fixing device 40 has reached the end of the life of the fixing device 40 based on the information (or the number of times information) of the fluctuation time Tz acquired from the rotation speed control unit 150. Specifically, the life determination unit 154 determines that the fixing device 40 has reached the end of its life when the fluctuation time Tz becomes the set time TC2 or more described above. When the life determination unit 154 determines that the life has been reached, the life determination unit 154 gives a predetermined notification to the display control unit 155.

When the display control unit 155 receives the predetermined notification from the life determination unit 154, the display control unit 155 displays the predetermined warning screen 1201 (see FIG. 17) on the operation panel 102.

The life determination unit 154 also gives a predetermined notification to the communication control unit 156 when a predetermined setting is made in the control device 101. The communication control unit 156 is connected to an external network. As a result, the image forming apparatus 100 can notify the external device that the fixing apparatus 40 has reached the end of its life.

Further, the control device 101 typically stops the subsequent image formation when it is determined that the fixing device 40 has reached the end of its life. However, the present invention is not limited to such control, and when it is determined that the fixing device 40 has reached the end of its life, image formation using the paper of the first paper type is permitted, and the image is formed more than the paper of the first paper type. The control device 101 may be configured so as not to allow image formation using the paper of the second paper type having a small basis weight. This is because the paper S having a large basis weight is less likely to cause a reverse loop state than the paper S having a small basis weight.

(Modification example)
As described above, the reverse loop state is unlikely to occur on paper having a basis weight larger than that of plain paper. On the other hand, paper having a small basis weight such as thin paper is more likely to have a reverse loop state than paper having a large basis weight.

As described above, the reverse loop usually does not occur in the paper having a basis weight larger than that of plain paper. Therefore, it is considered that the reason why the reverse loop occurs when using the paper S having a basis weight larger than the normal one is that the fixing device 40 has reached the end of its life. Therefore, it is preferable that the control device 101 keeps information on the fluctuation time Tz at the time of reverse loop control for each paper type (thin paper, plain paper, thick paper, etc.).

For example, the control device 101 may be configured so that when the fluctuation time Tz is the set time TC2 or more, the fixing device 40 determines that the life of the paper has a basis weight equal to or larger than that of plain paper. Alternatively, when the fluctuation time Tz of thin paper is set time TC2 or more, and when the fluctuation time Tz is set time TC2 or more for paper of a paper type having a basis weight of plain paper or more, the fixing device 40 has reached the end of its life. The control device 101 may be configured to determine.

<E. Summary ＞
(1) As described above, the image forming apparatus 100 includes a control device 101 that controls the operation of the image forming apparatus, a transfer apparatus (secondary transfer roller 33) that transfers an image onto paper S (recording material), and the like. It includes a fixing device 40 for fixing an unfixed image on the paper S on the paper S, and a sensor device 60 provided between the transfer device and the fixing device 40 and detecting the state of the paper S.

The transfer device conveys the paper S to the fixing device 40 at a predetermined speed. The fixing device 40 includes a pressure roller 408, and the pressure roller 408 conveys the paper S conveyed from the transfer device to the downstream side of the transfer path. When the paper S is bent in the first direction (the positive direction of the X axis as shown in FIG. 5), the sensor device 60 outputs a detection signal (predetermined signal) to the control device 101 and outputs the paper S to the control device 101. Is bent in the second direction (negative direction of the X axis as shown in FIG. 5) opposite to the first direction, the detection signal is not output to the control device 101.

The control device 101 controls the rotation speed of the pressurizing roller 408 to the speed VH (first speed) when there is an input of the detection signal, and when there is no input of the detection signal, the pressurizing roller 408 controls the rotation speed. The rotation speed of is controlled to a speed VL (second speed) slower than the speed VH. When the detection signal is not input for the set time TC1 (first time), the control device 101 changes the rotation speed of the pressurizing roller 408 until the detection signal is input. The control device 101 determines that the fixing device 40 has reached the end of its life when the time during which the rotation speed of the pressurizing roller 408 is changed exceeds the set time TC2 (second time).

It can be said that the reverse loop state is deteriorated when the time during which the rotation speed of the pressure roller 408 is fluctuated becomes longer. That is, it is assumed that the fixing device 40 has deteriorated.

Therefore, the life of the fixing device 40 can be determined by paying attention to the time during which the rotation speed of the pressurizing roller 408 is changed.

Further, according to the above configuration, in order to determine the life by focusing on the reverse loop phenomenon based on the deterioration of the fixing device 40, the structure is such that the torque threshold value of the pressurizing roller 408 used for determining the life is uniquely determined. In comparison, the life of the fixing device 40 can be determined with high accuracy. Therefore, according to the above configuration, the replacement period of the fixing device 40 can be extended, so that the life of the fixing device 40 becomes longer than before.

(2) The control device 101 changes the rotation speed of the pressure roller 408 by switching the rotation speed of the pressure roller 408 between the speed VH and the speed VL.

(3) The rotation speed is switched at a predetermined cycle. The control device 101 determines that the fixing device 40 has reached the end of its life when the number of times the rotation speed of the pressurizing roller 408 is switched exceeds the number of times determined by the cycle and the set time TC2.

(4) Of the number of times that the control device 101 controls to fluctuate the rotation speed of the pressurizing roller 408, the number of times the fluctuation time Tz that fluctuates the rotation speed of the pressurizing roller 408 becomes the set time TC2 or more. The fixing device 40 is determined to have reached the end of its life on condition that the ratio of According to the above configuration, it is possible to determine the life with higher accuracy.

(5) The control device 101 determines the life of the fixing device 40 every time a predetermined period elapses or every time the mileage of the pressurizing roller 408 increases by a predetermined distance.

(6) The sensor device 60 includes a lever 61 and a photo sensor 62. When the paper S is bent in the second direction (negative direction of the X-axis axis as shown in FIG. 5), the position of the lever 61 is the default position (first position), and the paper S is the first position. When the lever 61 is bent in the direction of 1 (the positive direction of the X-axis), the position of the lever 61 is moved from the default position to the end point position (second position) by the paper S. The photo sensor 62 outputs a detection signal to the control device 101 when the position of the lever 61 is the end point position.

(7) The time for changing the rotation speed of the pressure roller 408 is the cumulative value of the time (element time) for changing the rotation speed of the pressure roller 408 for each of the plurality of sheets S.

(8) Further, it can be said that the image forming apparatus 100 has the following configuration.
The image forming apparatus 100 has at least a fixing device 40 for fixing an unfixed image on the paper S on the paper S, and forms an image on the paper S. The image forming apparatus 100 has been transferred from the transfer device (transfer unit, secondary transfer roller 33) that transfers the image to the paper S and conveys the paper S to the downstream side of the transfer path, and from the transfer device in the fixing device 40. A pressurizing roller (pressurizing member) 408 that can rotate in the direction of transporting the paper S to the downstream side of the transport path, and a nip region for fixing the unfixed image G against the pressurizing roller 408 are formed. , A fixing belt 402 that rotates according to the rotation of the pressurizing roller 408, a sensor device (detection unit) 60 provided between the transfer device and the pressurizing roller 408 and detecting the state of the paper S, and control. A device (control unit) 101 is provided.

When the paper S is bent in the first direction (the positive direction of the X axis as shown in FIG. 5), the sensor device 60 outputs a detection signal (predetermined signal) to the control device 101 and outputs the paper S to the control device 101. Is bent in the second direction opposite to the first direction (the negative direction of the X axis in FIG. 5 and the like), the detection signal is not output to the control device 101.

The control device 101 controls the rotation speed of the pressurizing roller 408 to the speed VH (first speed) when there is an input of the detection signal, and when there is no input of the detection signal, the pressurizing roller 408 controls the rotation speed. The rotation speed of is controlled to a speed VL (second speed) slower than the speed VH. When the detection signal is not input for the set time TC1 (first time), the control device 101 changes the rotation speed of the pressurizing roller 408 until the detection signal is input. The control device 101 determines that the fixing device 40 has reached the end of its life when the time during which the rotation speed of the pressurizing roller 408 is changed exceeds the set time TC2 (second time).

<F. Control structure>
FIG. 11 is a flow chart showing a flow of processing executed by the control device 101.

In step S500, the control device 101 (specifically, CPU 131) determines whether or not the paper S has reached a predetermined position immediately before entering the fixing device 40. When it is determined that the product has been reached (YES in step S500), the control device 101 starts the above-mentioned positive loop control in step S510. If it is determined that the result has not been reached (NO in step S500), the control device 101 advances the process to step S500.

After step S510, in step S520, the control device 101 determines whether or not the paper S has passed the fixing device 40. When it is determined that the paper S has passed the fixing device 40 (YES in step S520), the control device 101 ends a series of processes. If it is determined that the paper S has not passed the fixing device 40 (NO in step S520), is the control device 101 continuously receiving the detection signal from the sensor device 60 from the sensor device 60 over the set time TC1 in step S530? Judge whether or not.

If it is determined that the detection signal has not been continuously received for the set time TC1 (YES in step S530), the control device 101 stops the positive loop control in step S540 and reduces the rotation speed of the pressurizing roller 408. Fluctuate. That is, the control device 101 starts the reverse loop control. If it is determined that the detection signal has been received (NO in step S530), the control device 101 advances the process to step S520.

After step S540, in step S550, the control device 101 determines whether or not the detection signal has been received from the sensor device 60. When it is determined that the detection signal has been received (YES in step S550), the control device 101 sets the time at which the rotation speed is changed in step S560 (that is, the fluctuation time Tz) to the flash memory 134 (see FIG. 2). Remember. Alternatively, the control device 101 stores the number of times the rotation speed is changed in the flash memory 134 instead of the fluctuation time Tz. After that, the control device 101 advances the process to step S520.

If it is determined that the detection signal has not been received (NO in step S550), the control device 101 determines in step S570 whether or not the paper S has passed the fixing device 40. If it is determined that the passage has passed (YES in step S570), the control device 101 stores the fluctuation time Tz or the number of fluctuations in the flash memory 134 in step S580. If it is determined that the passage has not been passed (NO in step S570), the control device 101 advances the process to step S550.

FIG. 12 is a flow chart showing a detailed flow of the process of step S510 of FIG.
In step S511, the control device 101 sets the rotation speed of the pressurizing roller 408 to the speed VH on the high speed side. In step S512, the control device 101 determines whether or not the detection signal has been received from the sensor device 60.

When it is determined that the detection signal has been received (YES in step S512), the control device 101 sets the rotation speed of the pressurizing roller 408 to the speed VL on the low speed side in step S513. If it is determined that the detection signal has not been received (NO in step S512), the control device 101 advances the process to step S511.

FIG. 13 is a flow chart showing a detailed flow of the process of step S540 of FIG.
In step S541, the control device 101 sets the rotation speed of the pressurizing roller 408 to the speed VH on the high speed side. In step S542, the control device 101 determines whether or not a predetermined time TD (see FIG. 9) has elapsed from the time when the rotation speed is set to the speed VH.

When it is determined that the predetermined time TD has elapsed (YES in step S542), the control device 101 sets the rotation speed of the pressurizing roller 408 to the speed VL on the low speed side in step S543. When it is determined that the predetermined time TD has not elapsed (NO in step S542), the control device 101 advances the process to step S542. That is, the control device 101 maintains the rotation speed of the pressurizing roller 408 at the speed VH until a predetermined time TD elapses.

After step S543, in step S544, the control device 101 determines whether or not a predetermined time TE (see FIG. 9) has elapsed from the time when the rotation speed is set to the speed VL.

When it is determined that the predetermined time TE has elapsed (YES in step S544), the control device 101 discards the process and proceeds to 541. If it is determined that the predetermined time TE has not elapsed (NO in step S544), the control device 101 advances the process to step S544. That is, the control device 101 maintains the rotation speed of the pressurizing roller 408 at the speed VL until the predetermined time TE elapses.

As described above, the control device 101 periodically changes the rotation speed of the pressurizing roller 408.

FIG. 14 is a flow chart showing the flow of the life determination process.
In step S601, the CPU 131 of the control device 101 reads out the time (that is, the fluctuation time Tz) at which the rotation speed is changed from the flash memory 134. The read timing is, for example, when a predetermined condition is satisfied.

Further, as the data to be read (variation time Tz), the data already read may be excluded. Each time the data is read, the CPU 131 may delete the read data from the flash memory 134. Alternatively, the CPU 131 may be configured to overwrite new data. How to retain and erase the data is not particularly limited.

After step S601, in step S602, the control device 101 determines whether or not the time (variation time Tz) at which the rotation speed of the pressurizing roller 408 is changed is equal to or longer than the set time TC2. When it is determined that the fluctuation time Tz is equal to or longer than the set time TC2 (YES in step S602), the control device 101 determines in step S603 that the life of the fixing device 40 has reached the end. That is, the control device 101 determines that the fixing device 40 has reached the end of its life. After that, in step S604, the control device 101 displays a warning on the operation panel 102.

On the other hand, when it is determined that the fluctuation time Tz is less than the set time TC2 (NO in step S602), the control device 101 determines in step S605 that the life of the fixing device 40 has not reached the end. That is, the control device 101 determines that the fixing device 40 has not reached the end of its life.

(Modification example)
FIG. 15 is a flow chart showing the flow of the life determination process of the fixing device 40 when the predetermined value TR is used.

In step S701, the CPU 131 of the control device 101 reads data (typically, a plurality of data) for one day of the time (variation time Tz) at which the rotation speed is changed from the flash memory 134. In step S702, the control device 101 determines whether or not the ratio of the number of data in which the time when the rotation speed is changed is the set time TC2 or more is equal to or more than the predetermined value TR among the plurality of data.

When it is determined that the ratio is equal to or greater than the predetermined value TR (YES in step S702), the control device 101 determines in step S703 that the fixing device 40 has reached the end of its life. After that, in step S704, the control device 101 displays a warning on the operation panel 102.

On the other hand, when it is determined that the ratio is less than the predetermined value TR (NO in step S702), the control device 101 determines in step S705 that the fixing device 40 has not reached the end of its life.

FIG. 16 is a flow chart showing the flow of the life determination process when the number of prints and the mileage are added to the life determination.

In step S671, the control device 101 tentatively determines whether or not the fixing device 40 has reached the end of its life based on the number of prints (the number of images formed) and the mileage of the pressure roller 408. Specifically, when the number of printed sheets exceeds a predetermined threshold value, the control device 101 tentatively determines that the fixing device 40 has reached the end of its useful life. Further, the control device 101 determines that the fixing device 40 has reached the end of its life when the mileage exceeds a predetermined threshold value.

When the fixing device 40 is tentatively determined to have reached the end of its life (YES in step S672), the control device 101 advances the process to step S601. If it is tentatively determined that the fixing device 40 has not reached the end of its life, the main determination that the fixing device 40 has not reached the end of its life is made in step S605.

Since the processes after step S601 are the same as the processes shown in FIG. 14, they will not be repeated here.

<G. User interface>
FIG. 17 is a diagram showing an example of a warning screen displayed on the operation panel 102.

Typically, the touch screen 120 of the operation panel 102 pops up a predetermined warning screen 1201. As a result, the user of the image forming apparatus 100 can know that it is time to replace the fixing apparatus 40.

<H. Life extension processing>
When the fixing device 40 is determined to have reached the end of its life as described above, it is usually necessary to replace the fixing device 40. However, it is also possible to extend the life of the fixing device 40 by performing the following processing.

For example, the control device 101 increases the rotation speed of the pressure roller 408 when the time during which the rotation speed of the pressure roller 408 is changed (variation time Tz) becomes longer. Alternatively, the control device 101 increases the load of the pressure roller 408 on the fixing member 490 as the time for varying the rotation speed of the pressure roller 408 increases.

[Embodiment 2]
The process of this embodiment is combined with the process of embodiment 1. That is, the image forming apparatus 100 executes the process described in the first embodiment and the process described in the present embodiment. Similarly, the processes of other embodiments 3, 4 and 5 described later are also combined with the processes of the first embodiment.

Specifically, in the present embodiment and other embodiments 3 and 4, the image forming apparatus 100 further increases the torque Tq as well as the time (or the number of fluctuations) at which the rotation speed of the pressurizing roller is changed. It is used to determine the life of the fixing device 40.

More specifically, it is tentatively determined whether or not the fixing device 40 has reached the end of its life by the process described in this embodiment or the process described in other embodiments 3 and 4. When it is tentatively determined that the fixing device 40 has reached the end of its life, it is determined (that is, this determination) whether or not the fixing device 40 has reached the end of its life by performing the determination process described in the first embodiment. If the fixing device 40 is not tentatively determined to have reached the end of its life, this determination is not performed.

Further, as described above, the control device 101 shall determine the life of the fixing device 40 each time a predetermined condition is satisfied. Specifically, the control device 101 determines the life of the fixing device 40 every time a predetermined period elapses.

Further, in the following, each embodiment will be described using the torque Tq, the average torque Tav as the average value of the torque Tq, and the moving average torque Tmav as the moving average value of the average torque Tav. Details of these torques will be described later. The same applies to the other embodiments 3 to 5 described later.

Further, for convenience of explanation, when the torque Tq, the average torque Tav, and the moving average torque Tmav are not distinguished, it is simply described as "torque Tg". That is, the torque Tg is a concept that includes the torque Tq, the average torque Tav, and the moving average torque Tmav. The same applies to the other embodiments 3 to 5 described later.

<A. Functional configuration>
FIG. 18 is a functional block diagram showing the functional configuration of the control device 101.

The image forming apparatus 100 includes a control device 101, a driving device 410, an operation panel 102, and a sensor device 60.

The control device 101 includes a rotation speed control unit 150, a torque acquisition unit 151, an average torque calculation unit 152, a moving average torque calculation unit 153, a life determination unit 154, a display control unit 155, and a communication control unit 156. To be equipped.

The torque acquisition unit 151 acquires the torque Tq (torque value) from the drive device 410. Specifically, the torque acquisition unit 151 acquires the torque Tq detected by the drive device 410 from the drive device 410 at predetermined intervals. Hereinafter, the case where the predetermined period is set to “1 day” will be described as an example. The predetermined period is not limited to one day.

In the case of this example, the torque acquisition unit 151 acquires the torque Tq up to five times a day from the drive device 410. Specifically, the torque acquisition unit 151 acquires the torque Tq from the drive device 410 when the pressurizing roller 408 is in contact with the fixing belt 402 and the paper is not being passed as shown in FIG. That is, the torque acquisition unit 151 acquires the torque of the motor 409 (hereinafter, also referred to as “idling torque”) from the drive device 410 when there is no load due to the paper S.

More specifically, the torque acquisition unit 151 acquires the torque Tq detected after the warm-up of the image forming apparatus 100 from the drive device 410. If the image forming apparatus 100 is warmed up five times in one day, the torque can be acquired five times. If the warm-up is performed only once a day, the control device 101 acquires the torque only once on this day. The number of times the torque Tq is acquired per day is not limited to five.

As described above, the "predetermined conditions" are, in the case of this example, "one day has passed" and "after the image forming apparatus 100 has been warmed up".

In the following, the torque (torque value) for five times acquired by the torque acquisition unit 151 from the drive device 410 is calculated as Tq (n [1]), Tq (n [2]), Tq (n [3]), Tq ( They are referred to as n [4]) and Tq (n [5]). Note that n is a variable representing a day.

The torque acquisition unit 151 sends the acquired torque for five times to the average torque calculation unit 152. When the torque can be acquired only four times, for example, the torque acquisition unit 151 typically transfers only Tq (n [1]) to Tq (n [4]) to the average torque calculation unit 152. send. Alternatively, the torque acquisition unit 151 sends Tq (n [1]) to Tq (n [5]) and notifies the average torque calculation unit 152 that the value of Tq (n [5]) is invalid. You may.

The average torque calculation unit 152 obtains the average value of the daily torque. Specifically, the average torque calculation unit 152 obtains the average value of the torques of five times (hereinafter, referred to as "average torque Tav") as shown in the following equation (1).

Tav (n) = (Tq (n [1]) + Tq (n [2]) + Tq (n [3]) + Tq (n [4]) + Tq (n [5])) ÷ 5 ... (1)
The average torque calculation unit 152 sends the calculated average torque Tav (n) to the moving average torque calculation unit 153.

The moving average torque calculation unit 153 calculates the moving average torque Tmav (moving average value) using the average torque Tav for 5 days. Specifically, the moving average torque calculation unit 153 uses the average torque Tav (n) of the day and the average torque (Tav (n-4), Tav (n-3), Tav) for four days from one day before to four days before. The moving average torque Tmav (n) is calculated using (n-2) and Tav (n-1)). Specifically, the moving average torque calculation unit 153 performs the calculation shown in the following equation (2).

Tmav (n) = (Tav (n-4) + Tav (n-3) + Tav (n-2) + Tav (n-1) + Tav (n)) ÷ 5 ... (2)
The moving average torque calculation unit 153 sends the calculated moving average torque Tmav (n) to the life determination unit 154. In the above, the moving average torque Tmav is calculated using the average torque Tav for 5 days (5 pieces), but the number of the average torque Tav is not limited to 5.

The life determination unit 154 determines whether or not the fixing device 40 has reached the end of its life. Specifically, the life determination unit 154 determines whether or not the life of the fixing device 40 has reached the end of the life based on the time information (or the number of times information) acquired from the rotation speed control unit 150 and the moving average torque Tmav. More specifically, the life determination unit 154 tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the moving average torque Tmav changes from an ascending change to a descending change. The life determination unit 154 is based on the time information (or the number of times information) acquired from the rotation speed control unit 150, as described in the first embodiment, on condition that the fixing device 40 has provisionally determined that it has reached the end of its life. It is determined whether or not the fixing device 40 has reached the end of its life (in the present embodiment, this determination).

FIG. 19 is a diagram showing a change over time in the moving average torque Tmav.
The horizontal axis of the graph (figure) represents the date. The vertical axis of the graph represents the moving average torque Tmav. In the example of FIG. 19, the moving average torque (Tmav (16) to Tmav (21)) from the 16th to the 21st of a certain month is plotted.

The moving average torque Tmav is increasing monotonically until the 20th. However, the moving average torque Tmav (21) on the 21st is smaller than the moving average torque Tmav (20) on the 20th of the previous day. That is, the relationship of "Tmav (n-1)> Tmav (n)" is established.

Therefore, the life determination unit 154 tentatively determines that the fixing device 40 has reached the end of its life at the time of the 21st day (specifically, when Tmav (21) is calculated). When the life determination unit 154 temporarily determines that the life is reached, the life determination unit 154 gives a predetermined notification to the display control unit 155.

When the display control unit 155 receives the predetermined notification from the life determination unit 154, the display control unit 155 displays the predetermined warning screen 1201 (see FIG. 17) on the operation panel 102.

The life determination unit 154 also gives a predetermined notification to the communication control unit 156 when a predetermined setting is made in the control device 101. The communication control unit 156 is connected to an external network. As a result, the image forming apparatus 100 can notify the external device that the fixing apparatus 40 has reached the end of its life.

In the above description, the torque acquisition unit 151 acquires the torque Tq detected after the warm-up of the image forming apparatus 100 from the drive device 410 as an example, but the present invention is not limited to this. For example, the control device 101 may be configured to acquire the torque Tq detected after fixing on the recording material from the drive device 410.

Further, the control device 101 typically stops the subsequent image formation when it is tentatively determined that the fixing device 40 has reached the end of its life. However, the present invention is not limited to such control, and when it is tentatively determined that the fixing device 40 has reached the end of its life, image formation using the paper of the first paper type is permitted, and the paper of the first paper type is used. The control device 101 may be configured so as not to allow image formation using the paper of the second paper type having a small basis weight. This is because the paper S having a large basis weight is less likely to slip in the nip region than the paper S having a small basis weight.

<B. Summary ＞
The image forming apparatus 100 includes a control device 101 that controls the operation of the image forming apparatus, and a fixing device 40 that fixes an unfixed image on the paper S (recording material) on the paper S.

The fixing device 40 includes a pressurizing roller 408 that can rotate in the direction of transporting the recording material to the downstream side of the transport path, a motor 409 that rotates the pressurizing roller 408, a drive device 410 that drives the motor 409, and pressurization. It includes an endless fixing belt 402 that rotates in accordance with the rotation of the roller 408, and a fixing member 490 that slidably supports the fixing belt 402 from the inner surface of the fixing belt 402. The fixing member 490 is pressurized by the pressure roller 408 at a position supporting the fixing belt 402.

The drive device 410 drives the motor 409 so as to keep the rotation speed of the pressurizing roller 408 constant based on the command from the control device 101. The drive device 410 detects the torque Tq when the motor 409 is driven.

The control device 101 acquires the detected torque Tq from the drive device 410. In the control device 101, the fixing device 40 has reached the end of its life because the change with time of the torque Tg (in this example, the moving average torque Tmav calculated based on the torque Tq) changes from an ascending change to a descending change. Tentatively determined.

Specifically, the control device 101 acquires the torque Tq from the drive device 410 a plurality of times each time a predetermined period (one day in the case of this example) elapses, and the average value of the torque Tq acquired over the plurality of times ( Average torque Tav) is calculated. The control device 101 calculates a moving average value (moving average torque Tmav) using the calculated average torque Tab and at least the previously calculated average torque Tab. When the calculated moving average torque Tmav becomes smaller than the previously calculated moving average torque Tmav, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life.

In the fixing device 40, as the fixing belt 402 rotates, the sliding sheet 406, which is a sliding portion, is gradually worn, and when the fixing belt 402 rotates, a load between the fixing belt 402 and the sliding sheet 406 is applied. Gradually increases. Therefore, in order to keep the speed of the pressure roller 408 constant, it is necessary to increase the torque Tq of the motor 409 that rotates the pressure roller 408. Therefore, the value of the torque Tq of the pressure roller 408 gradually increases with the lapse of days of use. As the value of the torque Tq increases, the value of the moving average torque Tmav also increases.

However, when the value of the torque Tq becomes high, the phenomenon that the paper S slips occurs in the fixing device 40 (specifically, the nip region).

When the paper S slips, the speed at which the pressure roller 408 feeds the paper S to the downstream side decreases. Therefore, the speed at which the pressurizing roller 408 sends the paper S to the downstream side is slower than the speed at which the secondary transfer roller 33 on the upstream side of the fixing device 40 sends the paper S to the fixing device 40.

As a result, a reverse loop state occurs between the secondary transfer roller 33 and the fixing device 40. The image deteriorates when a reverse loop occurs.

As described above, when the paper S slips, the value of the detected torque Tq becomes small. Therefore, the calculated moving average torque Tmav also becomes small.

Therefore, the image forming apparatus 100 tentatively determines that the fixing apparatus 40 has reached the end of its life because the change with time of the moving average torque Tmav changes from an ascending change to a descending change. According to such a configuration, the life of the fixing device 40 can be tentatively determined before the reverse loop occurs.

Further, according to the above configuration, the life of the fixing device 40 can be extended as compared with the configuration in which the torque threshold value of the pressure roller 408 used for the provisional determination of the life is uniquely determined.

Further, in this example, a tentative determination of the life is performed using the moving average torque Tmav. Therefore, even if noise is added to the torque, the influence of noise can be reduced. That is, it is possible to make a tentative determination of the life with higher accuracy than when the tentative determination is simply made based on the torque Tq.

Further, the control device 101 acquires the idling torque at the time of non-passing from the drive device 410 every time a predetermined period (in this example, one day) elapses. Specifically, the control device 101 acquires the torque Tq detected after the image forming device 100 is warmed up or fixed on the paper S from the drive device 410.

At such a timing, image formation is not performed. Therefore, the value of the torque Tq detected by the drive device 410 does not depend on the content of the unfixed image G on the paper S. Therefore, the control device 101 can tentatively determine the life with high accuracy by acquiring the torque Tq at such a timing.

<C. Control structure>
FIG. 20 is a flow chart for explaining the flow of processing executed by the image forming apparatus 100.

In step S1, the control device 101 determines whether or not the torque determination permission mode is set as the provisional determination mode for the life of the fixing device 40. As described above, the torque determination permission mode is a mode for provisionally determining the life of the fixing device 40 based on the time-dependent change of the torque Tg (in this example, the moving average torque Tmav). Typically, the torque determination permission mode is set by a service person.

When the control device 101 determines that the torque determination permission mode is set (YES in step S1), the control device 101 tentatively determines in step S2 whether or not the fixing device 40 has reached the end of its life based on the moving average torque Tmav.

When the control device 101 determines that the torque determination permission mode is not set (NO in step S1), the fixing device 101 determines in step S3 based on the number of prints on the image forming apparatus 100 and the mileage of the pressurizing roller 408. It is tentatively determined whether or not 40 has reached the end of its life. Typically, in the control device 101, when the number of printed sheets exceeds a preset reference number, or when the mileage of the pressurizing roller 408 exceeds a preset distance, the fixing device 40 reaches the end of its life. Temporarily determine that there is. That is, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life when either the condition of the number of prints or the condition of the mileage is satisfied.

FIG. 21 is a flow chart for explaining the details of the process of step S2 of FIG.
In step S21, the fixing device 40 sequentially detects the torque Tq of the pressurizing roller 408. In step S22, the control device 101 acquires the torque Tq at a predetermined timing from the fixing device 40 on each day. As described above, the control device 101 acquires, for example, the torque Tq detected after the warm-up of the image forming device 100 from the drive device 410.

In step S23, the control device 101 calculates the average value (average torque Tav) of the torque Tq up to five times on the same day. Specifically, the control device 101 executes the calculation of the above-mentioned equation (1). In step S24, the control device 101 calculates the moving average torque Tmav using the average value of five consecutive times.

In step S25, the control device 101 updates the current value (variable value) of the moving average torque Tmav with the value calculated in step S24. In step S26, if the moving average torque Tmav is the maximum, the control device 101 updates the maximum value (variable value) of the moving average torque Tmav with the moving average torque Tmav. The maximum value of the moving average torque Tmav is reset (typically set to zero) after the fixing device 40 is replaced. Therefore, the maximum value is the maximum value after the fixing device 40 is replaced.

In step S27, the control device 101 compares the calculated moving average torque Tmav with the moving average torque Tmav_old (1) of the previous day, and tentatively determines whether or not the fixing device 40 has reached the end of its life.

Assuming that the calculated moving average torque Tmav is Tmav (n) with reference to the formula (2), the moving average torque Tmav_old (1) on the previous day can be obtained by the following formula (3).

Tmav_old (1) = Tmav (n-1) = (Tav (n-5) + Tav (n-4) + Tav (n-3) + Tav (n-2) + Tav (n-1)) ÷ 5 ... (3)
FIG. 22 is a flow chart for explaining the details of the process of step S27 of FIG.

In step S271, the control device 101 determines whether or not the moving average torque Tmav is smaller than the moving average torque Tmav_old (1) of the previous day. If the control device 101 determines that it is small (YES in step S271), the control device 101 tentatively determines that the fixing device 40 has reached the end of its life in step S272. In step S273, the control device 101 displays a warning screen on the operation panel 102 as shown in FIG.

If the control device 101 determines that it is not small (NO in step S271), the control device 101 determines in step S274 that the fixing device 40 has not yet reached the end of its life.

<D. Modification example>
Hereinafter, a modified example of the provisional determination process of the life of the control device 101 will be described.

(D1. First modification)
FIG. 23 is a diagram showing a change over time in the moving average torque.

In the control device 101, when the change with time of the moving average torque Tmav changes from the rising change to the falling change, the fixing device 40 has a life on the condition that the moving average torque Tmav is equal to or higher than a predetermined threshold value Th1. Tentatively determined. That is, the control device 101 has a life of the fixing device 40 when the moving average torque Tmav is less than a predetermined threshold value Th1 even when the time-dependent change of the moving average torque Tmav changes from an ascending change to a descending change. Is not determined.

The reason for making the above determination using the threshold Th1 is that the moving average torque Tmav is sufficiently smaller than the value (numerical range) at which the paper S is considered to slip in the nip region, but the moving average torque is caused by noise or the like. This is because the value of Tmav may turn downward.

FIG. 24 is a flow chart for explaining the details of the process of step S27 of FIG. 21 in this modified example.

The flow chart of FIG. 24 differs from the flow chart shown in FIG. 22 in that it has step S275. That is, if the control device 101 determines in step S271 that it is small (YES in step S271), in step S275, it determines whether or not the moving average torque Tmav is equal to or greater than the threshold Th1. The threshold Th1 is a positive value.

When the control device 101 determines that the moving average torque Tmav is equal to or higher than the threshold value Th1 (YES in step S275), the control device 101 advances the process to step S272. When the control device 101 determines that the moving average torque Tmav is less than the threshold value Th1 (NO in step S275), the control device 101 proceeds to step S274.

(D2. Second modification)
FIG. 25 is a diagram showing a change over time in the moving average torque.

The control device 101 tentatively determines that the fixing device 40 has reached the end of its life on the condition that the amount of decrease ΔTmav is equal to or greater than the threshold value Th2 when the change with time of the moving average torque Tmav changes from the increase change to the decrease change. That is, even when the change with time of the moving average torque Tmav changes from the rising change to the falling change, the control device 101 does not determine the life of the fixing device 40 when the falling amount ΔTmav is less than the threshold Th2 or more. ..

The reason for performing the above determination using the threshold value Th2 is that the value of the moving average torque Tmav may turn downward due to noise or the like.

FIG. 26 is a flow chart for explaining the details of the process of step S27 of FIG.
The flow chart of FIG. 26 differs from the flow chart shown in FIG. 24 in that it has step S276. That is, when the control device 101 determines in step S275 that the threshold value is Th1 or higher (YES in step S275), the difference between the moving average torque Tmav and the moving average torque Tmav_old (1) in step S276 (that is, the moving average torque). It is determined whether or not the amount of decrease in Tmav (ΔTmav) is equal to or greater than the threshold Th2. The difference is an absolute value. The threshold Th2 is a positive value.

When the control device 101 determines that the descending amount ΔTmav is equal to or greater than the threshold value Th2 (YES in step S276), the control device 101 advances the process to step S272. When the control device 101 determines that the descending amount ΔTmav is less than the threshold value Th2 (NO in step S276), the control device 101 advances the process to step S274.

The determination process in step S275 may be omitted. That is, when the control device 101 is determined to be small in step S271 (YES in step S271), the process may proceed directly to step S276.

(D3. Third modification)
FIG. 27 is a diagram showing a change over time in the moving average torque.

The control device 101 calculates the previous time when the change with time of the moving average torque Tmav changes from the rising change to the falling change (that is, when the calculated moving average torque becomes smaller than the previously calculated moving average torque). On the condition that the calculated moving average torque is smaller than the moving average torque calculated two times before, the fixing device 40 is tentatively determined to have reached the end of its life. That is, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life on the condition that the moving average torque Tmav is lowered twice in succession. By such a determination process, the accuracy of the life determination of the fixing device 40 can be improved.

FIG. 28 is a flow chart for explaining the details of the process of step S27 of FIG. 21 in this modified example.

The flow chart of FIG. 28 differs from the flow chart shown in FIG. 22 in that it has step S277. That is, if the control device 101 determines in step S271 that it is small (YES in step S271), is the moving average torque Tmav_old (1) of the previous day smaller than the moving average torque Tmav_old (2) of the day before the previous day in step S277? Judge whether or not.

When the control device 101 determines that the moving average torque Tmav_old (1) is smaller than the moving average torque Tmav_old (2) (YES in step S277), the control device 101 proceeds to step S272. When the control device 101 determines that the moving average torque Tmav_old (1) is not smaller than the moving average torque Tmav_old (2) (NO in step S277), the control device 101 proceeds to step S274.

(D4. Fourth modification)
In the above example, from the viewpoint of improving the accuracy of the life determination, attention is paid to the change with time of the moving average torque Tmav. That is, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the moving average torque Tmav changes from an ascending change to a descending change.

However, the torque used for the tentative determination is not limited to the moving average torque Tmav. The average torque Tav may be used instead of the moving average torque Tmav. Alternatively, the torque Tq may be used instead of the moving average torque Tmav.

(1) Temporary determination of life based on average torque Tav The average torque calculation unit 152 of the control device 101 obtains the average value (average torque Tav) of five torques using the above equation (1).

In this modification, the life determination unit 154 of the control device 101 tentatively determines whether or not the life of the fixing device 40 has reached the end of the life based on the torque Tg (in the case of this example, the average torque Tav). Specifically, the life determination unit 154 tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the average torque Tav changes from an ascending change to a descending change.

More specifically, the control device 101 acquires torque from the drive device 410 a plurality of times each time a predetermined period (for example, one day) elapses, and the average value (average torque Tav) of the torque acquired over the plurality of times. ) Is calculated. When the calculated average torque Tav becomes smaller than the previously calculated average torque Tav, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life.

As described above, even when the life of the fixing device 40 is tentatively determined based on the change over time of the average torque Tav, the first modification, the second modification, and the third modification as described above are performed. The same processing as in the example can be applied.

When the first modification is applied to this example, it is as follows. The control device 101 determines that the fixing device 40 has reached the end of its life, provided that the average torque Tav is equal to or greater than a predetermined threshold value Th1'when the change with time of the average torque Tav changes from an ascending change to a descending change. Tentative judgment.

When the second modification is applied to this example, it is as follows. When the change with time of the average torque Tav changes from the rising change to the falling change, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life on the condition that the falling amount ΔTav is equal to or more than the threshold Th2'. The amount of decrease ΔTav in this case is the difference between the average torque Tav and the average torque Tav_old (1) of the previous day.

When the third modification is applied to this example, it is as follows. The control device 101 is calculated last time when the change over time of the average torque Tav changes from an ascending change to a descending change (that is, when the calculated average torque Tav becomes smaller than the previously calculated average torque Tav). On the condition that the average torque Tav is smaller than the average torque Tav calculated two times before, it is tentatively determined that the fixing device 40 has reached the end of its life.

In the case of this example, since it is not necessary to calculate the moving average torque Tmav, the control device 101 does not need to include the moving average torque calculation unit 153 shown in FIG.

(2) Temporary determination of life based on torque Tq In this modified example, the life determination unit 154 of the control device 101 has reached the end of the life of the fixing device 40 based on torque Tg (torque Tq in this example). Temporarily determine whether or not it has been done. Specifically, the life determination unit 154 tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the torque Tq changes from an ascending change to a descending change.

More specifically, the control device 101 acquires torque once from the drive device 410 every time a predetermined period (for example, one day) elapses. When the torque Tq becomes smaller than the previous torque Tq (torque Tq of the previous day), the control device 101 tentatively determines that the fixing device 40 has reached the end of its life.

As described above, even when the life of the fixing device 40 is tentatively determined based on the change over time of the torque Tq, the first modification, the second modification, and the third modification as described above are performed. The same processing as above can be applied.

When the first modification is applied to this example, it is as follows. The control device 101 tentatively determines that the fixing device 40 has reached the end of its life on the condition that the torque Tq changes from an ascending change to a descending change with time and the torque Tq is equal to or more than a predetermined threshold value Th1 ”. To do.

When the second modification is applied to this example, it is as follows. When the change with time of the torque Tq changes from the rising change to the falling change, the control device 101 tentatively determines that the fixing device 40 has reached the end of its life on the condition that the falling amount ΔTq is equal to or more than the threshold Th2 ″. In this case, the amount of descent ΔTq is the difference between the torque Tq and the torque Tq_old (1) on the previous day.

When the third modification is applied to this example, it is as follows. The control device 101 determines the previously detected torque Tq when the change with time of the torque Tq changes from an ascending change to a descending change (that is, when the detected torque Tq becomes smaller than the previously detected torque Tq). Is tentatively determined that the fixing device 40 has reached the end of its life on the condition that the torque Tq is smaller than the torque Tq detected two times before.

In the case of this example, since it is not necessary to calculate the average torque Tav and the moving average torque Tmav, the control device 101 includes the average torque calculation unit 152 and the moving average torque calculation unit 153 shown in FIG. There is no need to prepare.

(D5. Fifth modification)
In order to prolong the life of the fixing device 40, the control device 101 may be configured so as to shorten the set time TC2 on the condition that the change with time of the acquired torque Tq changes from the rising change to the falling change.

[Embodiment 3]
Hereinafter, the image forming apparatus according to the present embodiment will be described with respect to the differences from the second embodiment. The image forming apparatus according to the present embodiment has the same hardware configuration as the image forming apparatus 100 of the second embodiment. The data processing executed by the control device 101 is different from the data processing of the second embodiment. Therefore, in the following, the data processing executed by the control device 101 will be described.

In the second embodiment, the control device 101 acquires the torque Tq from the drive device 410 a plurality of times each time a predetermined period (for example, one day) elapses, and the average of the torque Tq acquired over the plurality of times. The value (average torque Tav) was calculated.

In the present embodiment, every time the mileage of the pressurizing roller 408 is extended by a predetermined distance, the torque Tq is acquired a plurality of times from the drive device 410, and the average value of the torque Tq acquired over the plurality of times (in the present embodiment). Also in the form, it is referred to as "average torque Tav").

The mileage is calculated as follows. First, the control device 101 acquires information on the rotation speed of the pressurizing roller 408 from the drive device 410. After that, the control device 101 calculates the mileage by multiplying the rotation speed by the rotation time of the pressurizing roller 408.

<A. Functional configuration>
FIG. 29 is a functional block diagram showing the functional configuration of the control device 101.

The image forming apparatus 100 includes a control device 101, a driving device 410, and an operation panel 102.

The control device 101 includes a rotation speed control unit 150, a torque acquisition unit 151A, an average torque calculation unit 152A, a moving average torque calculation unit 153A, a life determination unit 154A, a display control unit 155, and a communication control unit 156. To be equipped.

The torque acquisition unit 151A acquires the torque Tq (torque value) from the drive device 410. Specifically, the torque acquisition unit 151A acquires the torque Tq detected by the drive device 410 every time the traveling distance of the pressurizing roller 408 is extended by a predetermined distance from the drive device 410. In the following, a case where the predetermined distance is set to "10 km" will be described as an example.

The torque acquisition unit 151A acquires the torque Tq from the drive device 410 as a trigger when the mileage is extended by 10 km. Typically, the torque acquisition unit 151A acquires torque up to five times from the drive device 410 within the day when the detection is made after it is detected that the mileage has increased by 10 km. Specifically, the torque acquisition unit 151A acquires the torque from the drive device 410 when the pressurizing roller 408 is in contact with the fixing belt 402 and the paper is not being passed as shown in FIG.

More specifically, the torque acquisition unit 151A acquires the torque Tq detected after the warm-up of the image forming apparatus 100 from the drive device 410, similarly to the torque acquisition unit 151 of the second embodiment.

As described above, the "predetermined conditions" are, in the case of this example, "the mileage has been extended by 10 km" and "after the image forming apparatus 100 has been warmed up". As described in the second embodiment, instead of "after warming up the image forming apparatus 100", the control device 101 so as to acquire the torque Tq detected after fixing on the paper S from the driving device 410. May be configured.

The torque (torque value) for five times acquired by the torque acquisition unit 151A from the drive device 410 is Tq (m [1]), Tq (m [2]), Tq (m [3]), Tq (m [4]). ]), Tq (m [5]). In addition, m is a variable for distinguishing the distance every 10 km from each other. Every time the mileage increases by 10 km, the value of m increases by one.

The torque acquisition unit 151A sends the acquired torque for five times to the average torque calculation unit 152A.

The average torque calculation unit 152A obtains an average value of torque for each predetermined distance. Specifically, the average torque calculation unit 152 obtains an average value of five torques (hereinafter, referred to as "average torque Tav'") as shown in the following equation (4).

Tav'(m) = (Tq (m [1]) + Tq (m [2]) + Tq (m [3]) + Tq (m [4]) + Tq (m [5])) ÷ 5 ... (4)
The average torque calculation unit 152A sends the calculated average torque Tav'(m) to the moving average torque calculation unit 153A.

The moving average torque calculation unit 153A calculates the moving average torque Tmav'(moving average value) using the average torque Tav'for five times. Specifically, the moving average torque calculation unit 153A uses the average torque Tav'(m) of the day and the average torque of the last four times (Tav'(m-4), Tav'(m-3), Tav'(m). -2), Tav'(m-1)) and the moving average torque Tmav'(n) are calculated. Specifically, the moving average torque calculation unit 153A performs the calculation shown in the following equation (5).

Tmav'(m) = (Tav'(m-4) + Tav'(m-3) + Tav'(m-2) + Tav'(m-1) + Tav'(m)) ÷ 5 ... (5)
The moving average torque calculation unit 153A sends the calculated moving average torque Tmav'(m) to the life determination unit 154A. In the above, the moving average torque Tav'was calculated using the average torque Tav' of 5 times (5 pieces), but the number of the average torque Tav' is not limited to 5.

The life determination unit 154A tentatively determines whether or not the fixing device 40 has reached the end of its life. Specifically, the life determination unit 154A tentatively determines whether or not the life of the fixing device 40 has reached the end of the life of the fixing device 40 based on the time information (or the number of times information) acquired from the rotation speed control unit 150 and the moving average torque Tmav'. .. More specifically, the life determination unit 154A tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the moving average torque Tmav'changes from an ascending change to a descending change. The life determination unit 154 is based on the time information (or the number of times information) acquired from the rotation speed control unit 150, as described in the first embodiment, on condition that the fixing device 40 has provisionally determined that it has reached the end of its life. It is determined whether or not the fixing device 40 has reached the end of its life (in the present embodiment, this determination).

FIG. 30 is a diagram showing the time course of the moving average torque Tmav'.
The horizontal axis of the graph (figure) represents the mileage (km). The vertical axis of the graph represents the moving average torque Tmav'.

The moving average torque Tmav'is monotonically increased up to the distance L (m-1). However, the moving average torque Tmav'(m) at the distance L (m) is smaller than the moving average torque Tmav'(m-1) at the previous distance L (m-1). That is, the relationship of "Tmav'(m-1)> Tmav'(m)" is established.

Therefore, the life determination unit 154A tentatively determines that the fixing device 40 has reached the end of its life at the time point of the distance L (m) (specifically, the time point when Tmav'(m) is calculated). When the life determination unit 154A tentatively determines the life, it gives a predetermined notification to the display control unit 155.

When the display control unit 155 receives the predetermined notification from the life determination unit 154, the display control unit 155 displays a predetermined warning screen on the operation panel 102 (see FIG. 17).

<B. Summary ＞
The drive device 410 drives the motor 409 so as to keep the rotation speed of the pressurizing roller 408 constant based on the command from the control device 101. The drive device 410 detects the torque when the motor 409 is driven.

The control device 101 acquires the detected torque Tq from the drive device 410. The control device 101 tentatively determines that the fixing device 40 has reached the end of its life because the change with time of the torque Tg (moving average torque Tmav'in this example) changes from an ascending change to a descending change.

Specifically, the control device 101 acquires the torque Tq from the drive device 410 a plurality of times each time the traveling distance of the pressurizing roller 408 increases by a predetermined distance (10 km in this example), and the torque Tq acquired over the plurality of times. The average value of (average torque Tav') is calculated. The control device 101 calculates a moving average value (moving average torque Tmav') using the calculated average torque Tav'and at least the previously calculated average torque Tav'. When the calculated moving average torque Tmav'is smaller than the previously calculated moving average torque Tmav', the control device 101 tentatively determines that the fixing device 40 has reached the end of its life.

According to such a configuration, the effect described in the second embodiment can be obtained also in the present embodiment.

<C. Control structure>
Also in the present embodiment, the processing shown in FIG. 20 is performed as in the second embodiment.

FIG. 31 is a flow chart for explaining the details of the process of step S2 of FIG.
In step S21, the fixing device 40 sequentially detects the torque Tq of the pressurizing roller 408. In step S22A, the control device 101 acquires the torque Tq at a predetermined timing from the fixing device 40 each time the traveling distance of the pressurizing roller 408 is extended by a predetermined distance. As described above, the control device 101 acquires, for example, the torque Tq detected after the warm-up of the image forming device 100 from the drive device 410.

In step S23A, the control device 101 calculates the average value (average torque Tav') of the torque Tq up to five times on the same day. Specifically, the control device 101 executes the calculation of the above-mentioned equation (4). In step S24A, the control device 101 calculates the moving average torque Tmav'using the average value of five consecutive times.

In step S25A, the control device 101 updates the current value (variable value) of the moving average torque Tmav'with the value calculated in step S24A. In step S26A, if the moving average torque Tmav'is the maximum, the control device 101 updates the maximum value (variable value) of the moving average torque Tmav' with the moving average torque Tmav'. The maximum value of the moving average torque Tmav'is reset (typically set to zero) after the fixing device 40 is replaced. Therefore, the maximum value is the maximum value after the fixing device 40 is replaced.

In step S27A, the control device 101 compares the calculated moving average torque Tmav'with the previous moving average torque Tmav'_old (1), and tentatively determines whether or not the fixing device 40 has reached the end of its life.

Assuming that the calculated moving average torque Tmav'is Tmav'(m) with reference to the formula (5), the previous moving average torque Tmav'_old (1) is obtained by the following formula (6). Be done.

Tmav'_old (1) = Tmav'(m-1) = (Tav'(m-5) + Tav'(m-4) + Tav'(m-3) + Tav'(m-2) + Tav'(m-1) )) ÷ 5 ... (6)
FIG. 32 is a flow chart for explaining the details of the process of step S27A of FIG. 31.

In step S271A, the control device 101 determines whether or not the moving average torque Tmav'is smaller than the previous moving average torque Tmav'_old (1). When the control device 101 determines that the size is small (YES in step S271A), the control device 101 tentatively determines that the fixing device 40 has reached the end of its life in step S272. In step S273, the control device 101 displays a warning screen on the operation panel 102 as shown in FIG.

If the control device 101 determines that it is not small (NO in step S271A), the control device 101 determines in step S274 that the fixing device 40 has not yet reached the end of its life.

<D. Modification example>
Each process (first modification to fifth modification) shown in "<D. Modification>" of the second embodiment can be applied to the present embodiment as well.

For example, the application of "(d4. Fourth modification)" is as follows.
The control device 101 may be configured so that when the calculated average value (average torque Tav') becomes smaller than the previously calculated average value, the fixing device 40 is tentatively determined to have reached the end of its life.

Alternatively, the control device 101 may be configured so that when the acquired torque Tq becomes smaller than the previously acquired torque Tq, the fixing device 40 is tentatively determined to have reached the end of its life.

[Embodiment 4]
In the present embodiment, the life determination after it is determined that the torque determination permission mode is set is different from that of the second embodiment and the third embodiment. This point will be described below.

FIG. 33 is a flow chart for explaining the flow of processing executed by the image forming apparatus 100.

In step S1, the control device 101 determines whether or not the torque determination permission mode is set as the life determination mode of the fixing device 40.

When the control device 101 determines that the torque determination permission mode is set (YES in step S1), in step S2A, the number of prints on the image forming apparatus 100, the mileage of the pressurizing roller 408, and the moving average torque Tmav. Based on the above, it is tentatively determined whether or not the fixing device 40 has reached the end of its life.

When the control device 101 determines that the torque determination permission mode is not set (NO in step S1), the fixing device 101 determines in step S3 based on the number of prints on the image forming apparatus 100 and the mileage of the pressurizing roller 408. It is tentatively determined whether or not 40 has reached the end of its life.

As shown in step S2A, in the present embodiment, when the torque determination permission mode is set, not only the moving average torque Tmav'but also the number of prints and the mileage of the pressurizing roller 408 are taken into consideration. , The life of the fixing device 40 is tentatively determined. Therefore, the control device 101 can perform the life determination with higher accuracy in the torque determination permission mode.

[Embodiment 5]
In the present embodiment, a configuration will be described in which the image forming apparatus and the server apparatus (information processing apparatus) cooperate to determine the life of the fixing device 40. The configuration according to the present embodiment can be appropriately combined with the first to fourth embodiments.

FIG. 34 is a diagram showing a network configuration of the information processing system 1.
The information processing system 1 includes an image forming apparatus 100 and a server apparatus 900. The image forming apparatus 100 and the server apparatus 900 are communicably connected via the network 901. The image forming apparatus 100 communicates with the server apparatus 900 by the communication control unit 156 (see FIG. 18).

In the information processing system 1, the server device 900 acquires the torque Tq detected by the drive device 410 via the network 901. Further, the server device 900 calculates the average torque Tav (or Tav') and the moving average torque Tmav (or Tmav'). Further, the server device 900 determines the life of the fixing device 40 based on the moving average torque Tmav (or Tmav').

Even with such a configuration, the same effect as that described in the first to fourth embodiments can be obtained.

The information processing system 1 may be configured so that the image forming apparatus 100 calculates the moving average torque Tmav (or Tmav') and the server apparatus 900 determines the life.

[Embodiment 6]
In each of the above embodiments, the drive device 410 detects the torque when the motor 409 is driven, but the present invention is not limited to this. For example, the control device 101 may detect the torque when the motor 409 is driven. Alternatively, a device (not shown) in the image forming apparatus 100 may detect the torque when the motor 409 is driven.

At least, the image forming apparatus 100 may have a function of detecting the torque when the motor 409 is driven. Specifically, the torque detection unit 413 shown in FIG. 4 may be provided somewhere in the image forming apparatus 100. That is, the torque detection unit 413 may exist inside the fixing device 40 or outside the fixing device 40. The function of detecting such torque can be realized by using, for example, at least one processor.

When the image forming apparatus 100 determines the life of the fixing device 40, the control device 101 acquires the torque at the time of driving the motor 409 and the acquired torque every time a predetermined condition is satisfied. The life of the fixing device 40 may be determined based on the time during which the rotation speed of the pressurizing roller 408 is changed, provided that the change with time changes from an ascending change to a descending change.

Alternatively, when the server device 900 determines the life of the fixing device 40, when the server device (information processing device) 900 drives the motor 409 from the image forming device 100 each time a predetermined condition is satisfied. The life of the fixing device 40 is determined based on the time during which the rotation speed of the pressurizing roller 408 is changed, provided that the torque is acquired and the change over time of the acquired torque changes from an ascending change to a descending change. It may be a configuration to be performed.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Information processing system, 1C, 1K, 1M, 1Y imaging unit, 10 photoconductor, 11 charging roller, 12 exposure unit, 13 developer, 14 developing roller, 15B, 15C, 15K, 15M, 15Y toner bottle, 17, 53 Cleaning blade, 30 intermediate transfer belt, 31 primary transfer roller, 33 secondary transfer roller, 37 cassette, 40 fixing device, 48 tray, 60 sensor device, 61 lever, 62 photo sensor, 71 separation claw, 72, 73, 74, 75 Paper guide, 100 image forming device, 101 control device, 102 operation panel, 120 touch screen, 121 touch panel, 122 display, 134 flash memory, 135 communication IF, 150 rotation speed control unit, 151, 151A torque acquisition unit, 152 , 152A average torque calculation unit, 153,153A moving average torque calculation unit, 154,154A life judgment unit, 155 display control unit, 156 communication control unit, 401 heating member, 402 fixing belt, 403 holding member, 405 nip forming member, 406 sliding sheet, 407 curvature imparting member, 408 pressurizing roller, 409 motor, 410 drive unit, 411 motor control unit, 412 driver, 413 torque detector, 420 rotary encoder, 451 halogen heater, 452 housing, 454 connection Shaft, 490 fixing member, 611 rotating shaft, 900 server device, 901 network, 1201 warning screen, G unfixed image, R1, R2, R3 area, S paper.

Claims (22)

An image forming apparatus having at least a fixing device for fixing an unfixed image on a recording material on the recording material and forming an image on the recording material.
A transfer unit that transfers an image onto the recording material and conveys the recording material to the downstream side of the transfer path.
A pressurizing member that can rotate in the direction of transporting the recording material transported from the transfer unit in the fixing device to the downstream side of the transport path, and
A detection unit provided between the transfer unit and the pressurizing member and detecting the state of the recording material,
Equipped with a control unit
When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material has a second direction opposite to that of the first direction. When it is bent in the direction, the signal is not output to the control unit, and the signal is not output to the control unit.
The control unit
When the signal is input, the rotation speed of the pressurizing member is controlled to the first speed, and when the signal is not input, the rotation speed of the pressurizing member is set to the first speed. Control to a second speed that is slower than
When the signal is not input for the first time, the rotation speed of the pressurizing member is changed until the signal is input.
An image forming apparatus that determines that the fixing device has reached the end of its life when the time during which the rotation speed of the pressurizing member is changed exceeds the second time. The image according to claim 1, wherein the control unit changes the rotation speed of the pressurizing member by switching the rotation speed of the pressurizing member between the first speed and the second speed. Forming device. The switching is performed at a predetermined cycle, and the switching is performed.
The control unit determines that the fixing device has reached the end of its life when the number of times the rotation speed of the pressurizing member is switched is equal to or greater than the number of times determined by the cycle and the second time. 2. The image forming apparatus according to 2. The ratio of the number of times that the control unit controls to fluctuate the rotation speed of the pressurizing member is the number of times that the time during which the rotation speed of the pressurizing member is fluctuating is equal to or longer than the second time. The image forming apparatus according to any one of claims 1 to 3, wherein the fixing device is determined to have reached the end of its life on condition that the value is equal to or more than a predetermined value. Any one of claims 1 to 4, wherein the control unit determines the life of the fixing device every time a predetermined period elapses or every time the traveling distance of the pressurizing member increases by a predetermined distance. The image forming apparatus according to. The detection unit includes a lever and a photo sensor.
When the recording material is bent in the second direction, the position of the lever is the first position, and when the recording material is bent in the first direction, the recording material is bent. As a result, the position of the lever moves from the first position to the second position.
The image forming apparatus according to any one of claims 1 to 5, wherein the photo sensor outputs the signal to the control unit when the position of the lever is the second position. The control unit determines the life of the fixing device based on the time during which the rotation speed of the pressurizing member is changed, provided that the traveling distance of the pressurizing member is equal to or greater than a predetermined distance. The image forming apparatus according to any one of claims 1 to 6. A fixing belt that forms a nip region for fixing the unfixed image against the pressure member and rotates in accordance with the rotation of the pressure member.
A support member arranged inside the fixing belt and slidably supporting the fixing belt at a position facing the pressure member in order to counteract the pressure of the pressure member.
A motor that rotates the pressurizing member and
Further provided with a drive unit for driving the motor,
The control unit
Every time a predetermined condition is satisfied, the torque at the time of driving the motor is acquired, and the torque is acquired.
From claim 1, the life of the fixing device is determined based on the time during which the rotational speed of the pressurizing member is changed, on condition that the acquired change with time of the torque changes from an ascending change to a descending change. The image forming apparatus according to any one of 7. The predetermined condition is that the mileage of the pressurizing member is extended by a predetermined distance.
The control unit
Each time the traveling distance of the pressurizing member is extended by a predetermined distance, the torque is acquired a plurality of times, and the average value of the torques acquired over the plurality of times is calculated.
A moving average value is calculated using the calculated average value and at least the previously calculated average value.
On the condition that the calculated moving average value becomes smaller than the previously calculated moving average value, the life of the fixing device is determined based on the time during which the rotation speed of the pressurizing member is changed. The image forming apparatus according to claim 8. The predetermined condition is that a predetermined period has passed.
The control unit
Each time the predetermined period elapses, the torque is acquired a plurality of times, and the average value of the torque acquired over the plurality of times is calculated.
A moving average value is calculated using the calculated average value and at least the previously calculated average value.
On the condition that the calculated moving average value becomes smaller than the previously calculated moving average value, the life of the fixing device is determined based on the time during which the rotation speed of the pressurizing member is changed. The image forming apparatus according to claim 8. The control unit
Obtaining information on the rotation speed of the pressurizing member,
The image forming apparatus according to claim 9, wherein the mileage is calculated by multiplying the rotation speed by the rotation time of the pressurizing member. The image forming apparatus according to claim 9, wherein the control unit acquires the idling torque at the time of non-paper passing as the torque every time the traveling distance of the pressurizing member is extended by a predetermined distance. The image forming apparatus according to claim 10, wherein the control unit acquires the idling torque when the paper is not passed as the torque every time the predetermined period elapses. The image forming according to claim 12 or 13, wherein the control unit acquires the torque detected after the image forming apparatus is warmed up or fixed on the recording material as the idling torque when the paper is not passed. apparatus. The image forming apparatus according to claim 9 or 10, wherein the control unit determines that the fixing device has reached the end of its life on the condition that the calculated moving average value is equal to or higher than a predetermined threshold value. When the control unit determines that the fixing device has reached the end of its life, the second control unit permits image formation using the paper of the first paper type and has a smaller basis weight than the paper of the first paper type. The image forming apparatus according to any one of claims 1 to 15, which does not allow image forming using the paper of the paper type. With an additional operation panel
The image forming apparatus according to any one of claims 1 to 16, wherein the control unit displays a predetermined image on the operation panel when the fixing device is determined to have reached the end of its life. The image forming apparatus according to claim 8, wherein the control unit shortens the second time on condition that the acquired change with time of the torque changes from an ascending change to a descending change. The image forming apparatus according to any one of claims 1 to 18, wherein the control unit increases the rotation speed of the pressurizing member when the rotation speed of the pressurizing member is changed for a long time. The image forming apparatus according to claim 8, wherein the control unit increases the load of the pressurizing member on the support member when the rotation speed of the pressurizing member is changed for a long time. An information processing system including at least an image forming device for fixing an unfixed image on a recording material on the recording material, an image forming device for forming an image on the recording material, and an information processing device.
The image forming apparatus
A transfer unit that transfers an image onto the recording material and conveys the recording material to the downstream side of the transfer path.
A pressurizing member that can rotate in the direction of transporting the recording material transported from the transfer unit in the fixing device to the downstream side of the transport path, and
A fixing belt that forms a nip region for fixing the unfixed image against the pressure member and rotates in accordance with the rotation of the pressure member.
A detection unit provided between the transfer unit and the pressurizing member and detecting the state of the recording material,
With a control unit,
When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material has a second direction opposite to that of the first direction. When it is bent in the direction, the signal is not output to the control unit, and the signal is not output to the control unit.
The control unit
When the signal is input, the rotation speed of the pressurizing member is controlled to the first speed, and when the signal is not input, the rotation speed of the pressurizing member is set to the first speed. Control to a second speed that is slower than
When the signal is not input for the first time, the rotation speed of the pressurizing member is changed until the signal is input.
The information processing device
Information on the time during which the rotation speed of the pressurizing member is fluctuating is acquired from the control unit.
An information processing system that determines that the fixing device has reached the end of its life when the time during which the rotation speed of the pressurizing member is changed exceeds the second time. It is an information processing method in an image forming apparatus having at least a fixing device for fixing an unfixed image on a recording material on the recording material and forming an image on the recording material.
The image forming apparatus transfers the image onto the recording material and conveys the recording material to the downstream side of the transfer path, and the recording material conveyed from the transfer unit in the fixing device. A pressurizing member that can rotate in the direction of transporting to the downstream side of the transport path and a nip region that opposes the pressurizing member and fixes the unfixed image are formed, and the pressurizing member is driven by rotation. Includes a fixing belt that rotates, a detection unit that is provided between the transfer unit and the pressurizing member and that detects the state of the recording material, and a control unit.
When the recording material is bent in the first direction, the detection unit outputs a predetermined signal to the control unit, and the recording material has a second direction opposite to that of the first direction. If it is bent in the direction, the signal is not output to the control unit.
The information processing method is
When the control unit receives the signal input, the control unit controls the rotation speed of the pressurizing member to the first speed.
When the control unit does not input the signal, the control unit controls the rotation speed of the pressurizing member to a second speed slower than the first speed.
When the control unit does not receive the signal for the first time, the control unit changes the rotation speed of the pressurizing member until the signal is input.
An information processing method comprising a step of determining that the fixing device has reached the end of its life when the time for varying the rotation speed of the pressurizing member is equal to or longer than the second time.

Images