JP2006284629A - Fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing device capable of accurately predicting the lifetime of a film-like rotating body, and to provide an image forming apparatus provided with it. <P>SOLUTION: The fixing device, for performing heating and pressuring fixing, by sandwiching and conveying a recording material P carrying non-fixing images at a fixing part N of a heater 14 and a pressure roller 9, includes a fixing means, comprising the heater 14 and a fixing film 8, flanges 13a and 13b for regulating the position of the width direction of the fixing film 8, and the pressure roller 9 that is in contact with the reverse side face of a face-carrying non-fixing images of the recording material P by being pressure-contacted via the fixing film 8 on the heater 14. The fixing device comprises a lifetime prediction means for predicting the lifetime of the fixing film, on the basis of the speed of moving toward the flanges 13a and 13b by the fixing film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing device that fixes an unfixed image using an endless film, and an image forming apparatus including the fixing device.

  Conventionally, in an electrostatic recording apparatus or an electrophotographic apparatus, fixing of a toner image formed on a recording material is performed by a heating roller including a heating element such as a halogen lamp and a pressure roller having an elastic layer. In general, the recording material is nipped and conveyed.

  However, recently, in order to reduce power consumption and shorten the time from the start of energization to the temperature at which fixing can be achieved, a fixedly supported heating body (ceramic heater) is pressed against the heating body. A heater unit composed of a heat-resistant fixing film that is conveyed while being pressed, and a pressure member that brings the recording material into close contact with the heater unit, and applies the heat of the heating body to the recording material through the fixing film. Thus, a heat fixing device (film heat fixing device) for fixing a toner image formed on a recording material has been proposed (see Patent Documents 1 and 2).

  This system requires at least one drive roller and another pressure roller or tension roller, and is driven by the frictional force of the roller. For this reason, the configuration is complicated and expensive in order to keep fluctuations including the durability of the friction coefficient of the film and the surface of the driving roller, the applied pressure of the driving roller, the variation of the applied tension, and the fluctuation of durability within the allowable range. There are inconvenient points. In addition, since the cylindrical film is driven to rotate, depending on the configuration such as the pressure applied by the pressure roller and the thickness of the film, it is necessary to control the shift of the film, in which case the configuration is further complicated and expensive. There is an inconvenience.

  Therefore, the shift control is omitted by securing the buckling strength with the outer diameter and thickness of the film to the extent that the film does not buckle due to the shift force generated by driving the film. In addition, the fixing film is externally fitted to the film guide in a pressure-free manner, and the film is driven by pressing the film and the film guide is driven, whereby the recording material is driven by the pressure roller. A method of carrying is being put into practical use.

  FIG. 7 is a cross-sectional view of an essential part showing an example of a film heating type fixing device. The fixing film 108 is an endless belt-like thin film heat resistant film. The heater 14 is in a pressure contact state with a pressure roller 109 as a pressure member through the fixing film 108 with a predetermined contact pressure, and forms a fixing nip portion N.

  The recording material P as the heated material carrying the unfixed toner image Ta conveyed from the image forming unit side (C) (not shown) is in close contact with the film 108 and passes through the fixing nip N together with the film. Heat and pressure are applied in the process of passing through the fixing nip N. In this process, the toner image is softened, melted, and solidified to form a permanently fixed image Tb.

  However, the above conventional example has the following problems. When the accuracy of the film or the outer diameter accuracy of the pressure roller that drives the film is poor, a large offset force may be generated on the film, and the film end may be abnormally worn. If this state continues for a long time, as shown in FIG.

  This offset force is due to changes in the shape of the pressure roller due to endurance use, decrease in hardness, wear, change in surface friction coefficient due to contamination, film contamination, change in surface friction coefficient due to wear, change in grease amount, viscosity, and more Since it varies depending on various factors such as the installation environment of the apparatus at the user site, the type of sheet to be used, and the frequency of use of the apparatus, it is not easy to predict the film life.

  Therefore, if it is used with cracks occurring, the cracks gradually become larger and eventually the film is torn. As a result, a failure that requires replacement of the fixing device itself has occurred, and until the replacement of the fixing device, a period during which the user cannot use the image forming apparatus, so-called downtime, has occurred.

  Therefore, there is a need for a mechanism that allows service personnel to detect the need for replacement in advance and to perform maintenance on the fixing device. Conventionally, in order to achieve this, a method using a sheet passing number counter has been mainly used. It was.

  Specifically, the total transportable distance of the sheet estimated to be transportable until the fixing film reaches the end of its life is stored in the memory on the controller. The accumulated transport distance of the film calculated from the sheet passing number information counted by the counter and the size information of the sheet to be actually passed is slightly before the total transportable distance registered in the memory on the controller is reached. At this stage, a signal notifying that the life of the fixing film is near is output.

By using these life detection methods, it is theoretically possible to prevent troubles caused by film end breakage and to replace the film before the trouble occurs.
JP-A-63-313182 Japanese Patent Laid-Open No. 2-157878

  However, while these conventional life detection methods can inform you that the life of the fixing film is near the cumulative transport distance, it is not possible to predict when the fixing film will reach the end of its life. Can not. This is because, as described above, the offset force of the film, which causes the life due to the end damage of the fixing film, varies greatly depending on various factors, so that a uniform total transportable distance is guaranteed for the fixing films of all products. It is impossible. In addition, the period required for the lifetime cannot be constant. Therefore, with the conventional life detection method, it is difficult not only to flexibly cope with the usage status of the apparatus, but also to determine from which user the maintenance should be preferentially performed. For this reason, there has been a problem that the efficiency of service work is deteriorated or that a so-called downtime occurs during a period in which the user cannot use the image forming apparatus because the replacement is not in time.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a fixing device capable of accurately predicting the lifetime of a film-like rotating body and an image forming apparatus including the same. There is.

In order to achieve the above object, in the fixing device according to the present invention,
A fixing means comprising a heating means and a film-like rotating body;
Regulating means for regulating the position of the rotating body in the width direction;
Pressurizing means that is in pressure contact with the heating means via the rotating body and is in contact with the surface opposite to the surface carrying the unfixed image of the recording material;
A fixing device that sandwiches and conveys a recording material carrying an unfixed image at a press-contact portion between the heating unit and the pressing unit, and performs heating and pressure fixing;
It has life prediction means for predicting the life of the rotating body based on the speed at which the rotating body moves toward the regulating means.

  According to the present invention, it is possible to accurately predict the lifetime of a film-like rotating body.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. . Further, the materials, shapes, etc. of the members once described in the following description are the same as those in the first description unless otherwise described.

(Schematic configuration of image forming apparatus)
FIG. 2 is a cross-sectional view of a copying machine as an example of an image forming apparatus that can be suitably used in the present invention.

  A digital copying machine (hereinafter referred to as an image forming apparatus) 1 shown in FIG. 2 includes an image reading unit 3 at the top, an image forming unit 4 at the top inside, a discharge processing unit 5 at the discharge unit, an automatic document feeder 2 at the top, A feeding cassette 71 for stacking the sheet-like recording material P in the central portion, a manual feed tray 72, and a double-sided tray 73 capable of forming images on both sides of the recording material P are provided below the inside.

  The automatic document feeder 2 is a device for automatically feeding a document on the document glass 31. The automatic document feeder 2 includes a document tray 21 for a document to be copied, a feed roller 22 for feeding the document, a separation belt and a transport roller 23 for picking up the documents one by one, and a document glass for only one document taken out. A registration roller transported onto 31, a reversing roller 24 that reverses the original when copying on both sides, and a discharge roller 25 that discharges the original after copying is provided. The originals set on the original tray 21 are conveyed one by one onto the original glass 31, and are read and discharged.

  When the image reading unit 3 first sets a document (not shown) on the document glass 31 and issues an instruction to start copying, the exposure device 32 moves in the direction of arrow A while irradiating the document, and scans the front surface of the document. To do. The light irradiated by the exposure device 32 is reflected by the original, is turned back by the second and third mirrors 33 and 34, passes through the lens 35, is read by the CCD 36, and the image data is recorded in the image memory.

  The image forming unit 4 forms an image on the recording material P. A photosensitive drum 43 that is rotationally driven at the time of image formation, a laser unit 41 that irradiates the photosensitive drum 43 with a laser beam based on image data read by the CCD 36, and a rotational direction around the photosensitive drum 43. Therefore, a charger 44, a developing device 45, a transfer device 46, a separator 47, and a cleaning device 48 are provided in this order.

  After the surface of the photosensitive drum 43 is uniformly charged by the charger 44, the laser beam emitted from the laser unit 41 is folded back by the laser mirror 42 and read by the image reading unit 3 on the surface of the photosensitive drum 43. An electrostatic latent image of the original image is formed. This electrostatic latent image is developed by the developing device 45. The developed image is transferred by the transfer unit 46 to the recording material P fed from the feeding cassette 71 to form a document image.

  The developer remaining on the surface of the photosensitive drum 43 to which the developed image has been transferred is removed by the cleaning device 48. The separator 47 separates the recording material P on which the image is transferred from the photosensitive drum 43. Thereafter, the developer is conveyed to the fixing device 49 and the developer is fixed on the recording material P. The recording material P after the fixing process is conveyed to the discharge unit.

  When copying on both sides, the recording material P whose front surface is fixed is conveyed to the double-sided tray 73, reversed, fed again to the image forming unit 4, and an image is formed on the back side. In addition, an operation unit 17 that is connected to a controller 80, which will be described later, and designates a copying operation and the like and a display unit 18 that displays an operation state, an abnormal state, and the like are provided (see FIG. 1).

  The discharge processing device 5 uses a sorter, a finisher, or the like, and sorts and discharges the recording material P on which an original image is formed on a discharge tray (sort bin or stack tray). In this embodiment, it is assumed that a finisher is used as shown in FIG.

(Schematic configuration of fixing device)
FIG. 3 is a cross-sectional view of a fixing device 49 that can be suitably used in the present invention. FIG. 4 is a front sectional view of the fixing device.

  The fixing device according to the present embodiment includes a fixing unit composed of a heater 14 and a fixing film 8 that is a film-like rotating body as heating units, and flanges 13a and 13b as regulating units that regulate the position of the fixing film 8 in the width direction. And a pressure roller 9 as pressure means that is in pressure contact with the heater 14 via the fixing film 8 and is in contact with the surface opposite to the surface carrying the unfixed image of the recording material P. A recording material P carrying an unfixed image is nipped and conveyed at a pressure contact portion (fixing nip portion N) with the pressure roller 9 to perform heat and pressure fixing.

  The fixing film 8 is a single layer film having heat resistance, toner releasability, and toughness, or a composite layer film subjected to desired surface treatment or lamination treatment. For example, a heat-treated polyimide (P1) single layer film of about 60 μm, or a composite layer film in which the film surface is further treated with a release layer with tetrafluoroethylene (PTFE) or the like can be suitably used.

  In the fixing device 49 of this embodiment, the fixing film 8 is an endless cylindrical rotating body, and no tension is applied except in the nip portion N in the circumferential direction, and the fixing film 8 is rotated only by a frictional force with the pressure roller 9. A configuration that travels is adopted.

  The fixing device 49 includes a film guide member 10 that guides the inner surface of the fixing film 8 over the entire length direction, a heater 14 that serves as a heating unit that contacts the guide member 10, and a pressure roller 9. The heater 14 is disposed inside the fixing film. Further, the heater 14 and the pressure roller 9 are in a pressure contact state with a predetermined contact pressure (for example, A4 width and total pressure 5 to 25 kg) by pressure springs 11a and 11b with the fixing film 8 interposed therebetween.

The surface of the heater 14 is provided with a linear or narrow strip-like thin film heating resistor portion such as TaSiO ₂ , silver palladium, Ta ₂ N, RuO ₂ , or nichrome formed by vapor deposition, sputtering, CVD, screen printing, or the like. .

  The recording material P to which the unfixed toner image is transferred is conveyed to the fixing nip portion N together with the fixing film 8 by the surface frictional force of the pressure roller 9 rotated by the drive gear 12. Thereafter, at least in the fixing nip N, the sheet is fed in the traveling direction at the same speed as the fixing film 8 and the pressure roller 9 without slipping due to the contact pressure by the pressure springs 11a and 11b.

  The passage process in the fixing nip N is a heating and pressing process, and the heat of the heater 14 is transmitted to the recording material P through the fixing film 8, and the unfixed toner on the recording material P is melted / softened and pressed. .

  After passing through the fixing nip N, the fixing film 8 and the recording material P are conveyed while being kept in close contact by the adhesive force of the melted / softened toner. The heat of the melted and softened toner is radiated by using this transport process as a cooling process, the toner is cooled and solidified, and a permanently fixed image is formed on the recording material P.

  After the cooling process, the fixing film 8 and the recording material P are easily separated by cooling and solidifying the toner, and the recording material P is discharged from the fixing device 49.

(Life prediction means)
Next, the structure of the life prediction means for predicting the life of the fixing film by predicting the end damage due to the shift of the fixing film will be described.

  As described above, the fixing device of this embodiment has a configuration in which the shift control of the fixing film is omitted for the purpose of simplifying the configuration and reducing the cost. Reference numerals 13a and 13b shown in FIG. 4 denote flanges, and the fixing film 8 is positioned between the two flanges 13a and 13b and is subjected to position regulation in the width direction.

  As described above, when the accuracy of the fixing film 8 and the outer diameter accuracy of the pressure roller 9 that drives the fixing film 8 are poor, or the shape of the pressure roller 9 changes due to use durability, the hardness decreases, wear, and surface friction due to contamination. Change in coefficient, contamination of fixing film 8, change in surface friction coefficient due to wear, change in grease amount, viscosity, and various other factors such as the installation environment of the device at the user site, the type of sheet used, and the frequency of use of the device Due to the factor, the shifting of the fixing film 8 occurs.

  When the end of the fixing film 8 is received by being moved toward the flange 13, the end of the fixing film 8 is strongly pressed against the flange 13 by the strong moving force of the fixing film 8. At that time, the rigidity of the fixing film 8 may lose the pressing force, and the film end may buckle or wrinkle. Here, the state in which the end of the film is finally damaged and the unfixed image cannot be fixed is called the life of the fixing film.

  Thus, in order to detect that the film is near the end of its life before the film reaches the end of its life, it is preferable to provide a moving speed detecting means for knowing the state of the film being shifted.

  FIG. 1 is a perspective view of the vicinity of the film moving speed detecting means. In this embodiment, an unassigned portion 8b that does not regularly apply an opaque release layer surface treatment in the width direction of the fixing film is provided on the Ra outside the sheet passing area of at least one end portion 8a in the width direction of the fixing film 8. . The transmissive photosensor 15 is configured to repeat on and off by detecting the non-given portion 8b and moving toward the fixing film 8, that is, in the width direction. In addition, instead of forming the non-given portion, a minute unevenness that regularly changes the detection signal of the sensor may be provided. Alternatively, regions having different surface reflectances may be provided alternately and regularly, and a moving speed in the width direction may be detected by detecting a signal using a reflective photosensor.

  In this embodiment, the moving speed in the width direction (the direction toward the flanges 13a and 13b) detected using the photosensor 15 as the moving speed detecting means and the controller 80 is an evaluation value representing the shift of the film. In this embodiment, the moving speed of the film is detected when the image forming apparatus is rotated before feeding, and the moving speed in the width direction of the fixing film is detected at any time during image formation.

  Next, a method for predicting the life time due to end damage of the fixing film by the life prediction means will be described. In the image forming apparatus 1 of the present embodiment, a predetermined threshold value K of the moving speed y in the fixing film width direction is set and stored in advance in a memory built in the controller 80 as a storage unit. That is, the memory is a reference speed storage unit that stores a predetermined speed (threshold value K) that serves as a reference for determining whether or not to start a calculation for predicting the life of the fixing device 49 compared with the moving speed y. This threshold value K is set with a predetermined margin with respect to the limit speed L immediately before the film reaches the end of its life. A controller 80 that functions as the control means of the apparatus and also as the life prediction means when the actual film offset force monitored by the photosensor 15 and the controller 80, that is, the moving speed reaches the threshold value K, will be described later. A life prediction operation is performed using the prediction function to predict the life time due to the end damage of the fixing film.

  For the calculation of the life prediction by the controller 80, the offset force of the corresponding film, that is, the moving speed y in the width direction detected by the photosensor 15 is used. Further, the time measuring means for measuring the operation time of the fixing film 8 measures information on the time since the fixing film 8 was last replaced (for example, the operation time t from the initial state of the fixing film 8 to the present time), and The operation time t is used for calculation of life prediction. The operating time t of the fixing film 8 may be measured using a clock function as a time measuring means built in the controller 80 of the image forming apparatus main body. In addition, the limit speed L immediately before the fixing film 8 reaches the end of its life is stored in advance in a memory as limit movement speed storage means included in the controller 80.

  In this embodiment, the controller 80 moves the fixing film 8 in the width direction detected by the photosensor 15 and the controller 80, the operation time t of the fixing film 8 measured by the clock function in the controller 80, the controller The phenomenon is approximated by a prediction curve combining a linear function and a quadratic function as a prediction function using the limit speed L or threshold value K stored in the memory 80 (see FIGS. 5 and 6).

  When a fixing film has a life characteristic such that the degree of advancement of the fixing film is small at an initial stage, but rapidly increases as it approaches the end of its life, it is difficult to approximate the phenomenon with a linear function. This is because the prediction is likely to deviate from the actual result due to factors such as individual differences of the fixing film and disturbance. For this reason, in this embodiment, a prediction curve is determined by a two-stage process, and the final life of the fixing film is predicted.

  For the life prediction, the linear function portion of the prediction curve may be used. In this embodiment, a method (life calculation algorithm) for predicting the life time of the fixing film from the quadratic function portion will be described. .

  This film life prediction procedure (life calculation algorithm) consists of the following two stages. (I) A preliminary prediction curve serving as a base is determined based on a known reference curve. (Ii) In order to improve accuracy, the preliminary prediction curve is corrected according to the actual phenomenon, and a final prediction curve is created. Then, a life prediction calculation is performed according to the function.

  First, when the width direction moving speed y of the fixing film exceeds a preset threshold value, the process (i) is performed, and then the timing delay rate is confirmed again after a predetermined period (ii). Perform the process. The specific contents of the processing will be described below with reference to FIGS.

A prediction curve (hereinafter referred to as a prediction curve by referring to a quadratic function portion) is expressed by the following equation (y) where the moving speed in the width direction is y, the operation time is t, and the vertex coordinates of the quadratic function are (M, N) Defined in 1). In the following equation (1), B is a coefficient of inclination of the quadratic function, M is the X coordinate (time axis) of the vertex of the quadratic function, and N is the Y coordinate (width direction moving speed axis of the quadratic function). ).
y = B × (t−M) ² + N (1)

The parameters B and M are values that change depending on the usage state of the image forming apparatus main body. As the curve shape, if the usage frequency is high, the parameter is compressed in the time axis direction with respect to t = 0, and conversely if the usage frequency is low. It is in the relationship of being expanded in the same direction. That is, if one width direction moving speed transition curve at a certain usage frequency is known in advance, a prediction curve can be created even in cases where the usage situation is different. In this embodiment, the width direction moving speed transition curve when the feeding operation is performed at a rate of 1000 sheets / day is sampled in advance, and a reference prediction curve (hereinafter referred to as a reference curve) is defined. A function representing the reference curve (see FIG. 5) at this time is represented by the following formula (2).
y = B0 × (t−M0) ² + N0 (2)

  In addition, the time when the width direction moving speed y that serves as a trigger for performing the film life prediction reaches the threshold value K1 is defined as T0 (known). As described above, the reference curve shown in FIG. 5 is an approximate curve obtained from the data of the speed transition that has been investigated in advance, and the parameter values (specific values of B, M, and N) are the controller values. 80 is stored in advance in a memory included in 80.

  The process (i) will be described based on this reference curve. When the fixing film 8 is used and the actual film being monitored by the photosensor 15 and the controller 80, that is, when the width direction moving speed y reaches the threshold value K1, the preliminary prediction curve determination process shown in FIG. 5 is performed. Do. The clock function built in the controller 80 can measure the actual operation time T1 from the previous replacement of the fixing film 8 to that time, so the magnification difference b in the time axis direction between the reference curve and the current travel speed transition curve. Is obtained by the following equation (3).

As a result, the parameters B and M of the current prediction curve are determined by the following equations (4) and (5), respectively, the movement speed in the width direction is y, the operation time is t, and the vertex coordinates of the quadratic function are (M0 × b , N0), a function (formula (6)) of the preliminary prediction curve shown in FIG. 5 is calculated.
b = T1 / T0 (3)
B = B0 / b ² (4)
M = M0 × b (5)
y = (B0 / b ² ) × (t−M0 × b) ² + N0 (6)

At this time, when the time when the reference curve reaches the limit speed L, that is, the life time is Te0, the life time Te1 of the preliminary prediction curve can be calculated by the following equation (7) from the magnification difference b. Prediction may be performed at this point, but prediction calculation is not yet performed for higher accuracy.
Te1 = b × Te0 = (T1 × Te0) / T0 (7)

Next, the process (ii) for performing the life prediction calculation after resetting the prediction curve to improve the accuracy will be described. First, at T2 after a predetermined time set in advance from the process (i), the moving speed y in the width direction of the fixing film is measured again. The speed y at this time is K2. Of the parameters of the quadratic function that determines the prediction curve, when the time axis coordinate M of the vertex is fixed to M0 × b of the preliminary prediction curve, it passes through two points (T1, K1) and (T2, K2), and the vertex Is a curve (final prediction curve shown in FIG. 6) on t = M0 × b.
K1 = B × (T1-M0 × b) ² + N (8)
K2 = B × (T2−M0 × b) ² + N (9)

That is, assuming that B and N obtained as solutions of the above simultaneous equations and equations (8) and (9) are B2 and N2 for simplification, the function of the final prediction curve shown in FIG. 10).
y = B2 × (t−M0 × b) ² + N2 (10)

Based on the function representing this final prediction curve, the controller 80 performs a life prediction calculation, and calculates the time Te when the width direction moving speed y of the fixing film reaches the limit speed L by the following equation (11) (secondary function). .
Te = ((L−N2) / B2) ^1/2 + M0 × b (11)

  According to the film life prediction procedure, (i) a preliminary prediction curve as a base is determined based on a known reference curve, and (ii) the preliminary prediction curve is corrected in accordance with an actual phenomenon to improve accuracy. Create a final prediction curve. When the life prediction calculation is performed according to the function, the controller 80 automatically transmits the calculation result to the service center through the network line. Thereby, the service person of the service center can grasp when the film exchange should be performed by when.

  In this embodiment, after the final prediction curve is determined, the lifetime is not re-predicted. However, the prediction curve may be corrected several times and the lifetime may be re-predicted until the end of the lifetime.

  As described above, according to the present example, the progress of the shift is particularly slow in the initial state, but it is effective in predicting the lifetime of a film having a characteristic of moving in the width direction at an accelerated rate when the lifetime is approaching. In addition, it becomes possible to predict the life time of the film, which varies depending on factors such as individual differences of the film and disturbances, more flexibly and with very high accuracy. As a result, troubles such as the occurrence of downtime can be reliably prevented.

  In addition, when the life prediction means predicts the life of the fixing film, the life time information is transmitted to an information terminal (service station) outside the image forming apparatus through the network, so that the service station side incorporates it in the user's device. It is possible to accurately grasp the replacement time of the film. For this reason, it is possible to optimize which of the many devices at the user's site should be preferentially used for film replacement. As a result, there is no downtime due to replacement delay, service quality can be dramatically improved, and service operations can be made much more efficient.

  In addition, it is not possible to replace a film that still has a margin until the end of its life, but it is possible to replace it after it has been fully used up, so that an effect of reducing running costs can be obtained.

  In the above-described embodiments, the life prediction calculation is performed when the moving speed of the fixing film in the width direction exceeds the threshold value, but the present invention is not limited to such a method. For example, the calculation may be performed periodically, or a sequence in which the calculation is frequently performed after the threshold value is exceeded may be used. Alternatively, the execution signal may be given so as to perform the life prediction calculation from the outside such as the service station side.

  In the above-described embodiment, the elapsed time since the last film replacement was used for life prediction as it is. However, for example, the period during which the power was not turned on for a long time may be excluded from the operation time. In addition to time information, paper counter information is also used in combination (for example, the calculation formula is changed depending on whether the deviation is severe or not even though the number of sheets is small, or a sudden change in usage frequency is detected. Thus, prediction can be performed with higher accuracy.

  In the above-described embodiment, when the film life time is predicted, the life time information is transmitted to an information terminal (service station or the like) outside the image forming apparatus through the network. Is not limited to this. For example, when the life prediction means predicts the life of the fixing film, it may be displayed on a display means (not shown) of the operation unit of the image forming apparatus, or may be recorded on a recording material and output. Anyway.

It is a perspective view of the film movement speed detection means vicinity which concerns on this invention. 1 is a cross-sectional view of a copying machine as an example of an image forming apparatus that can be suitably used in the present invention. 1 is a cross-sectional view of a fixing device that can be suitably used in the present invention. 1 is a front sectional view of a fixing device that can be suitably used in the present invention. It is a figure for demonstrating the lifetime prediction algorithm in this invention. It is a figure for demonstrating the lifetime prediction algorithm in this invention. It is a principal part sectional view showing an example of a fixing device of a film heating system. It is a figure showing the edge part damage of a fixing film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Automatic document feeder 3 Image reading part 4 Image forming part 5 Discharge processing apparatus 8 Fixing film 8a End part 8b Unapplied part 9 Pressure roller 10 Film guide member 11a, 11b Pressure spring 13a, 13b Flange 14 Heater 15 Transmission type photosensor 41 Laser unit 43 Photosensitive drum 44 Charger 45 Developer 46 Transfer device 47 Separator 48 Cleaning device 49 Fixing device 80 Controller K Threshold L Limit speed N Fixing nip P Recording material t Operating time y Movement speed

Claims (7)

A fixing means comprising a heating means and a film-like rotating body;
Regulating means for regulating the position of the rotating body in the width direction;
Pressurizing means that is in pressure contact with the heating means via the rotating body and is in contact with the surface opposite to the surface carrying the unfixed image of the recording material;
A fixing device that sandwiches and conveys a recording material carrying an unfixed image at a press-contact portion between the heating unit and the pressing unit, and performs heating and pressure fixing;
A fixing device comprising: a life predicting unit that predicts a life of the rotating body based on a speed at which the rotating body moves toward the regulating unit. Furthermore, speed detecting means for detecting a moving speed at which the rotating body moves toward the regulating means,
Reference speed storage means for storing a predetermined speed as a reference for determining whether to start calculation for predicting the life of the rotating body compared to the moving speed;
A time measuring means for measuring the operating time of the rotating body, wherein the life predicting means is a moving speed of the rotating body detected by the speed detecting means and an operation of the rotating body measured by the time measuring means. The fixing device according to claim 1, wherein the life of the rotating body is predicted based on time and a predetermined speed stored in the reference speed storage unit.   The fixing device according to claim 2, wherein the operating time of the rotating body measured by the time measuring unit does not include a time when the power is not turned on. Image forming means for forming an image on a recording material;
A fixing device according to any one of claims 1 to 3,
An image forming apparatus comprising:   5. The information communication unit according to claim 4, further comprising an information communication unit capable of sending the predicted information to an information terminal outside the image forming apparatus through a network when the life prediction unit predicts the life of the rotating body. Image forming apparatus.   The image forming apparatus according to claim 4, further comprising: a display unit that displays the predicted information when the life prediction unit predicts the life of the rotating body.   The image forming apparatus according to claim 4, wherein when the life prediction unit predicts the life of the rotating body, the predicted information is recorded on a recording material and output.

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