JP3247250B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus provided with a fixing device for cleaning a fixing roller with a cleaning web.

[0002]

2. Description of the Related Art Generally, in a color image forming apparatus such as a copying machine and a laser beam printer, for example, charging,
Form a toner image on the photosensitive drum by exposure and development,
After repeating a series of image forming processes such as transferring the toner image onto the recording material a plurality of times, a multi-colored toner image is formed on the recording material, and these toner images are fixed by a fixing device to form a color image. It has gained. For this type of image forming apparatus, for example, DSA2607
727, and JP-A-50-50935.

[0003] Referring to the drawings, an outline of the above-described image forming apparatus will be described, and then, cleaning of a conventional fixing device will be described. FIG. 9 is a vertical cross-sectional view of the color image forming apparatus. As shown, a photosensitive drum 1 and a charging roller 3 are disposed substantially at the center of the apparatus main body M. In the same figure, a rotary developing device 4 is disposed on the right side of the photosensitive drum 1. The developing device 4 includes four developing cartridges 4a, 4b, 4c, and 4d, and a rotating support 9 on which the developing cartridges are mounted. Each developing cartridge is a cartridge in which a toner storage unit for storing toner of each color (for example, yellow, magenta, cyan, and black) and a developing unit for performing development are integrally formed as a cartridge. Be exchanged.
The rotating support 9 rotates the developing cartridge of a predetermined color to be used for development by rotating in the direction of arrow R4.
It is arranged at a developing position facing the photosensitive drum 1. Each of the developing cartridges has a developing opening surface 5a, 5b, 5c, 5d when placed at the developing position.
The photosensitive drum 1 is supported by a rotating support 9 so as to face the surface. FIG. 10 shows a detailed view of the developing cartridge. Developing cartridges 4a, 4b, 4c, 4d
Contains a yellow toner Y, a magenta toner M, a cyan toner C, and a black toner B, respectively. Each developing cartridge further includes a coating roller 6
a, 6b, 6c, 6d, toner regulating members 7a, 7b, 7
c, 7d, and with the rotation of the developing rollers 8a, 8b, 8c, 8d, the toner application rollers 6a, 6b, 6c, 6
The toner is applied onto the developing rollers 8a, 8b, 8c, and 8d on the image forming device d, and a necessary tribo is given to the toner by the toner regulating members 7a, 7b, 7c, and 7d. The material of these regulating members is preferably nylon or the like when the toner is charged to a negative polarity, and when charged to a positive polarity,
Silicon rubber is good. That is, a material that is charged to a polarity opposite to the polarity to be applied to the toner by friction is preferable. It is preferable that the peripheral speed of each developing roller is selected in the range of 1.0 to 2.0 of the peripheral speed of the photosensitive drum 1.
Further, the developing cartridge 4 mounted on the rotary support 9
a, 4b, 4c, and 4d are in a state of maintaining a fixed posture as shown in FIG.
b, 4c, 4d developing opening surfaces 5a, 5b, 5c, 5d
Are always driven in a posture facing the surface of the photosensitive drum 1. One means of this driving method is described in detail in JP-A-50-93437. In addition, these developing cartridges are intended to eliminate the hassle of toner supply and maintenance, etc.
It allows users who have no special knowledge and skills to easily exchange. Further, it is preferable to use a one-component developer which has a simple cartridge structure, is low in cost, and is easy to miniaturize, as the toner used in the developing cartridge. However, it goes without saying that a two-component developer may be used.

In FIG. 9, a transfer drum 10 having a function of holding a recording material (not shown) and transferring a toner image on the photosensitive drum 1 onto the recording material is disposed on the left side of the photosensitive drum 1. I have.

In forming an image, the photosensitive drum 1 is driven to rotate in the direction of arrow R10 at a peripheral speed of 100 mm / sec by driving means (not shown). In addition, the photosensitive drum 1
A photoconductor made of an organic photoreceptor (OPC) is applied to the outer peripheral surface of an aluminum cylinder having a diameter of 40 mm.
The present invention is not limited to the above-described OPC, but may be A-Si, CdS, Se, or the like.

Next, a laser diode 11, which constitutes an exposure apparatus, a polygon mirror 13, which is driven to rotate by a high-speed motor 12, a lens 14, and a folding mirror 15, are arranged above the apparatus main body M. The charging roller 3 has a DC voltage of -700 V and an AC frequency of 700H.
At z, an AC voltage of V _PP (peak-to-peak) of -1500 V is superimposed and charged uniformly to approximately -700 V.

When a signal based on magenta image information is input to the laser diode 11, a laser beam is applied to the photosensitive drum 1 through an optical path 16,
In this case, the portion irradiated with the laser beam becomes almost -100 V, and an electrostatic latent image is formed. When the photosensitive drum 1 further rotates in the direction of arrow R1, the electrostatic latent image is visualized by a predetermined developing cartridge among the developing cartridges 4a, 4b, 4c, and 4d to become a toner image.

Next, the transfer process will be described in detail. A recording material is fed from a recording material cassette 17 by a pickup roller 18 in synchronization with the toner image on the photosensitive drum 1 and is attracted to the transfer drum 10. The transfer drum 10 has a 2-mm-thick elastic layer 20 wound around a metal cylinder 19 having a diameter of 156 mm, and further has a 100 μm-thick
, And rotates in the direction of arrow R10 at substantially the same speed as the photosensitive drum 1. In addition, urethane foam was used as the elastic layer 21. When the recording material is supplied to the transfer drum 10, the recording material is held by the gripper 22, and the toner image on the photosensitive drum 1 is applied to a voltage between the photosensitive drum 1 and the transfer drum 10 by a high-voltage power supply (not shown). Is transferred onto a recording material (not shown). The recording material is simultaneously attracted to the surface of the transfer drum 10 by charge injection into itself. The recording material may be attracted to the transfer drum 10 in advance by applying a voltage between the transfer drum 10 and the attraction roller 23 as necessary.

By performing the above-described image forming process for cyan, yellow, and black in the same manner, a plurality of color toner images can be transferred onto a recording material. The recording material to which the color image has been transferred is peeled off from the transfer drum 10 by the separation charger 2 and the separation claw 24, and further fused and fixed by a conventionally known heating and pressure fixing device 30. Is discharged as a typical product.
On the other hand, residual toner remaining on the photosensitive drum 1 without being transferred to the recording material is cleaned by a known cleaning device 26 such as a fur brush or a blade. Further, the toner on the transfer drum 10 is also cleaned by the fur brush 28 and the transfer drum cleaning device 27. After forming a patch for image density detection on the transfer drum 10 and detecting the density with the density sensor 29 to perform density control,
Similarly, the cleaning is performed, and the patches on the transfer drum 10 are removed.

Next, cleaning of the fixing device 30 will be described in detail.

In recent years, the development of desktop type printers, especially, electrophotographic laser beam printers has been remarkable. The fixing device in this printer has a fixing roller and a pressure roller in contact with the fixing roller, and a recording material on which a toner image has been transferred by an image forming unit is inserted into a nip portion of both rollers. In general, fixing is performed by heating and pressing. In this fixing device 30, in order to prevent the toner melted by heat from being offset to the fixing roller, a heat-resistant release layer made of silicon rubber, fluororesin, or the like is provided on the surface of the fixing roller, and further, the surface of the fixing roller is A release agent such as silicone oil is applied.

However, despite these measures,
The offset toner gradually accumulates on the surface of the fixing roller, and the offset toner deteriorates the fixing roller, resulting in shortening the service life. For this reason, a method of removing the offset toner from the surface of the fixing roller by performing cleaning by forced friction using a fibrous web, a pat, or the like is generally performed. Between 1
Several exchanges and maintenance are performed by service personnel or users. For example, conventionally, a fixing roller for fixing an unfixed toner image carried on a recording material, and a belt-shaped cleaning web that is wound from one supply roller to another winding roller while rubbing against the surface of the fixing roller. In the fixing device having the cleaning roller, the cleaning web has a total length (effective length) of which the winding-up completion time by the above-described winding-up roller and the fixing-roller replacement-required time estimated in advance (hereinafter referred to as “estimated replacement-required time”). ").). A sensor for detecting a notice of completion of winding of the cleaning web; a holding mechanism for holding the notice of completion of winding of the cleaning web; a sensor for detecting completion of winding of the cleaning web; The above-mentioned fixing device is arranged to be exchangeable by a notifying (displaying) means for notifying that it is outside.

The replacement timing detecting mechanism of the conventional fixing device will be described with reference to FIG. In FIG. 11, reference numeral 52 denotes a web supply roller (web supply member).
Supply. 53 is a web take-up roller (web take-up roller) for taking up the cleaning web 51. 5
A web pressing roller 4 presses the cleaning web 51 against the fixing roller. Reference numerals 56 and 57 denote latch mechanisms, which mechanically move the cleaning web 5 to the web winding completion notice detection position M1 and the web winding completion detection position M2.
When a mark attached near the rear end of the first mark 1 reaches, the mark is mechanically detected and the sensors 58 and 59 are accessed. This operation is maintained as it is once accessed, regardless of whether the power is on or off. 58 and 59 are a web winding completion notice sensor and a web winding completion detecting sensor, respectively. Web winding completion notice detection position M
The interval between 1 and the web winding completion detection position M2 is set in advance to a length that allows for a predetermined number of recording materials to be passed. After the mark on the cleaning web 51 is detected by the web winding completion notice detection sensor 58, the system control unit 39 sets the cleaning web 51
Is displayed on the display circuit 40 to prompt replacement of the fixing device, and thereafter, when the web winding completion detection sensor 59 detects the mark, the fixing device is stopped.

[0014]

However, after the notice of completion of the web winding is detected, a predetermined number of recording materials are passed to the fixing device 30 by elongation of the cleaning web 51 or excessive turning on / off of the power switch by the user. However, the completion of the web winding is detected before the fixing is performed, and there is a possibility that the fixing device 30 may be unduly quickly replaced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus in which replacement of a fixing device is performed at a favorable time.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a fixing roller for contacting an unfixed toner on a recording material and fixing the unfixed toner on the recording material. An image forming apparatus having a fixing device having a cleaning web that removes offset toner by rubbing against the surface of the fixing roller while being wound by a web winding member from a web supply member. The completion time of winding the cleaning web by the web winding member is set so as to coincide with the estimated replacement time of the fixing roller, and the completion of winding of the cleaning web is detected. Notice detection means and, based on the output of the winding completion notice detection means, indicating that the fixing device is about to be replaced,
Display means for prompting the exchange of the fixing device when a predetermined number of recording materials have been fixed after the output of the winding completion notice detecting means, and at least the web supply member, the web winding member, The cleaning web and the fixing roller are integrated into a unit, and the unit is exchangeably mounted on the main body of the image forming apparatus.

In this case, take-up driving means for driving the web take-up member, paper-pass detection means for detecting whether or not the recording material has passed through the fixing device, and the output from the paper-pass detection means, A winding unit that has a counting unit that counts the number of sheets passed through the recording material, a storage unit that stores the count number of the counting unit, and a comparison unit that compares whether the count number has reached a predetermined number. After detecting the upcoming winding of the cleaning web through the completion notice detecting unit, the winding driving unit winds the cleaning web until the comparing unit detects that the count number has reached a predetermined number. The picking may be continued.

The drive speed of the winding drive means is
It can be changed depending on the type of the recording material.

Further, based on the output of the comparing means,
A calculating unit for calculating the number of sheets that can be fixed until the winding by the web winding member is completed; and a storage unit for storing a calculation result of the calculating unit. The calculation result is sequentially updated and displayed on the display unit. It may be.

[0020]

The effective length of the cleaning web is determined so that the winding completion time coincides with the estimated replacement time of the fixing roller, that is, when the fixing is performed on the estimated number of recording materials. It is set so that the winding of the cleaning web is completed and the fixing roller reaches the end of its life almost at the same time. That is, the life of the fixing roller is converted into the number of recording materials that can be fixed by the fixing roller before the life, and this number corresponds to the effective length of the cleaning web. This means that when the fixing is performed on one recording material, the length of the cleaning web to be wound is set to be constant correspondingly.

Based on the above premise, the near completion of the winding of the cleaning web is detected to indicate this, and then, when a predetermined number of recording materials have passed through a fixing device (for example, a fixing roller), the cleaning is performed. Since the completion of the winding of the web is detected and displayed, when the completion of the winding is detected, the fixing device has already reached the replacement time.

Further, since the winding is completed when a predetermined number of recording materials have been passed after the winding completion is detected, it is not necessary to provide a sensor for detecting the winding completion.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a sectional view schematically showing the structure of a fixing device 30. The fixing device 30 includes a fixing roller 31 and a pressure roller 32. The pressure roller 32 disposed below the fixing roller 31 is pressed against the fixing roller 31 with a predetermined pressing force, and forms a nip N with the fixing roller 31. The fixing roller 31 is driven to rotate in the direction of arrow R31 by a driving unit (not shown), and accordingly, the pressure roller 32 is driven to rotate in the direction of arrow R32. Halogen heaters 33 and 34 are provided inside the fixing roller 31 and the pressure roller 32, respectively. The heat of the heaters 33 and 34 is transmitted to the surfaces of the fixing roller 31 and the pressure roller 32. A thermistor 35 is arranged on the surface of the fixing roller 31 so as to come into contact with the fixing roller 31.
The temperature of one surface is detected, and the temperature of the fixing device 30 is adjusted based on the detection result. The above-described thermistor 35 may be arranged so as to be in contact with the core of the fixing roller 31 to detect the temperature of the core.

A fixing roller cleaning device 50 is disposed above the fixing roller 31. The fixing roller cleaning device (hereinafter simply referred to as “cleaning device”) 50 includes a cleaning web 51, a web supply roller (web supply member) 52 for supplying the cleaning web 51, and a web winding roller (web winding roller) for winding the cleaning web 51. And a web pressing roller 54 for pressing the cleaning web 51 against the fixing roller with an appropriate pressing force.

The cleaning web 51 shown in FIG.
Is made of a fiber material slightly impregnated with high-viscosity silicone oil. The effective length of the cleaning web (the length provided for cleaning the fixing roller 31) is set so that the completion time of winding the cleaning web by the web winding roller 53 coincides with the estimated replacement time of the fixing roller 31. Have been. The web take-up roller 53 for taking up the cleaning web 51 is driven to rotate by a take-up driving section (take-up driving means; not shown in FIG. 2A; see FIG. 3) 55. This rotational drive is adjusted by pulse control of a solenoid, whereby the cleaning web 51 is sent in the direction of arrow K51 at a much lower speed than the peripheral speed of the fixing roller 31. The feeding amount of the cleaning web 51 is set so that a predetermined amount of winding is performed by one pulse drive. The web supply roller 52 is driven to rotate in the direction of the arrow R52 as the cleaning web 51 moves in the direction of the arrow K51.

In the vicinity of one end of the web supply roller 52,
A winding completion notice detecting unit 60 that detects that the winding of the cleaning web 51 is almost completed is provided. Winding completion notice detecting means 60 has flags 6 at both ends.
A detection member 61 having 1 a and 61 b and swinging about a shaft 61 c is provided, and a completion notice sensor 62. One flag 61a is lightly placed on the edge of the upper surface of the cleaning web 51. A notch 51a is provided at an end near the winding end of the cleaning web 51 on which the flag 61a is placed. As the winding of the cleaning web 51 progresses,
When the remaining amount of the cleaning web 51 decreases and the notch 51a reaches the web winding completion notice detection position (hereinafter, referred to as "M position") as shown in FIG. One flag 61a falls in the direction of arrow a, the entire detection member 61 rotates in the direction of arrow c, and the other flag 61b moves in the direction of arrow b. At this time, the flag 61b traverses the completion notice sensor 62, whereby the winding completion notice of the cleaning web 51 is detected.

At least the web supply roller 52, the web take-up roller 53, the cleaning web 51, and the fixing roller 31 among the members constituting the transfer device 30 are integrally formed as a unit.
At the time of the completion of winding 1 and the estimated replacement time of the fixing roller (both times are equal), the unit is integrally removed from the image forming apparatus main body and replaced with a new unit.

Next, the electric system will be described with reference to the block diagram of FIG.

In FIG. 3, reference numeral 36 denotes a paper discharge sensor which is installed downstream of the fixing roller 31 (see FIG. 1),
Detects that fixing has been completed and the sheet has been discharged. Reference numeral 39 denotes an image forming apparatus control unit (hereinafter, simply referred to as a “control unit”).
It performs sequence control, data calculation, comparison, etc. related to image formation. Reference numeral 55 denotes a web take-up driving unit, which includes a solenoid, a one-way clutch, and the like, and performs a predetermined amount of feeding drive if a continuous time for applying power to the solenoid is longer than a predetermined value. Reference numeral 62 denotes the above-mentioned completion notice sensor, and the completion of the winding of the cleaning web 51 is determined by the recording material P.
Is a sensor for detecting completion after a predetermined number of sheets have passed. Reference numeral 41 denotes a non-volatile memory (storage means), which has a power source separately from the main body of the apparatus, and is constituted by a random access memory or the like which can freely write and read data. Reference numeral 42 denotes a DC power supply connected to the switch circuit 43 for operating the control unit 39, the completion notice sensor 62, the solenoid, and the like. When the power supply of the apparatus is turned on by a user or the like, or when abnormality processing is performed due to a jam or the like, the control unit 39 performs initialization of the apparatus to drive the web take-up drive and perform take-up control. this is,
This is to prevent the recording material P from being stained or jammed by the offset toner solidified on the surface of the fixing roller 31 due to a low temperature.

Next, the operation will be described with reference to the flowchart of FIG.

In step S1, when power is supplied to the apparatus, the control section 39 initializes the apparatus. In step S2, the control section 39 drives the web take-up driving section 55 to feed the cleaning web 51 in the direction of arrow K51. I do. If the apparatus main body is performing a printing operation (S3), it has a response from the paper discharge sensor 36. If printing is not being performed, a print command is awaited. When the unfixed toner image on the recording material P is fixed by the fixing device 30 and passes through the paper ejection sensor 36 (S4), the count value of the number of passed sheets is incremented by a counting means (not shown) in the control unit 39. (S5), the count value is overwritten in the nonvolatile memory (storage means) 41 (S7). This count value is retained even if the power of the apparatus main body is turned off. If it is not detected that the paper has been passed from the paper discharge sensor 36 within the predetermined time, it is determined that a jam has occurred (S6). In S8, if the output from the completion notice sensor 62 for notifying completion of web winding is valid and the updated counter value is a predetermined value, the cleaning web is compared by the comparing means (not shown) in the control unit 39. It is determined that the winding of 51 has been completed,
A display prompting replacement of the fixing device 30 is displayed by the display circuit (display means) 40 (S10). On the other hand, if the web winding completion notice is not detected and the updated counter value does not satisfy the predetermined value, the web winding drive is performed and the apparatus stands by until the next fixing operation. <Embodiment 2> FIG. 5 is a block diagram of Embodiment 2.

When a toner image is fixed on an OHP sheet instead of plain paper as the recording material P, a releasing agent may be used on the OHP sheet in order to improve the releasability. In particular, color fixing using a color image is performed. The apparatus is used for presentations in many cases, and fixing is often performed by switching a fixing speed and a fixing temperature in order to enhance light transmittance, and the amount of toner offset tends to increase. Therefore, the cleaning web take-up control needs to be performed about five times faster. In FIG. 5, a recording material detection sensor 45 detects whether the recording material P is an OHP sheet or plain paper. The other configuration is the same as that of the first embodiment, and the description is omitted.

FIGS. 6 and 7 are flow charts for explaining the operation according to the type of the recording material P. The description of the same components as those in FIG. 4 is omitted.

In FIG. 6, S20 is an individual process depending on the type of the recording material P, the details of which are shown in FIG. After discriminating whether the recording material P is a plain paper or an OHP sheet in S21 (S22), the corresponding sheet passing count value is set (S24, S25). For example, for plain paper, the set value is set to 10, and for OHP sheets, the set value is set to 2. If the recording material P cannot be identified by the recording material detection sensor 45, it is determined that there is no paper or jam (S23). When the fixing operation is completed and there is an output from the paper discharge sensor 36 (S26, S27), the sheet passing count value is incremented and it is checked whether there is a continuous fixing operation command (S28, S29). If not, the process waits until the next fixing operation command is issued. If continuous, it is checked whether the sheet passing count value is the same as the set value set above (S30).
If the sheet passing counter value is the same as the set value, the individual processing according to the type of the recording material P ends. The subsequent operation is performed according to the first embodiment.
Is the same as <Embodiment 3> FIG. 8 shows a block diagram of Embodiment 3.

In the figure, reference numeral 46 denotes an interface circuit for exchanging commands, data, status, etc. with the external device 47. In the third embodiment, the control unit 39 is different from the first embodiment in that the nonvolatile memory 41
Is read out, and the difference between the predetermined value and the predetermined value is calculated, and the result is transferred to the external device 47 through the interface circuit 46. As a result, the external device 47 does not change the recording material P until the fixing device 30 is replaced.
It is possible to check how many more sheets can be passed, that is, the degree of margin until the fixing device 30 is replaced. The following fixing device can be prepared accordingly.

[0036]

As described above, according to the present invention,
The completion of winding of the cleaning web is detected to indicate this, and then, when a predetermined number of recording materials have passed through a fixing device (for example, a fixing roller), the completion of winding of the cleaning web is detected. Since this is displayed, when the completion of winding is detected, the fixing device has already reached the replacement time, and the fixing device will not be replaced unduly early.

Since the winding is completed when a predetermined number of recording materials have been passed after the near completion of winding is detected, the fixing device is not provided without a sensor for detecting the completion of winding. You can know exactly when to replace.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the entire configuration of a fixing device according to a first embodiment.

FIGS. 2A and 2B are perspective views illustrating an operation of the fixing roller cleaning device according to the first exemplary embodiment.

FIG. 3 is an electric block diagram of the first embodiment.

FIG. 4 is a flowchart illustrating an operation of the fixing roller cleaning device according to the first exemplary embodiment.

FIG. 5 is an electric block diagram of a second embodiment.

FIG. 6 is a flowchart illustrating the operation of a fixing roller cleaning device according to a second embodiment.

FIG. 7 is a flowchart illustrating the operation of a fixing roller cleaning device according to a second embodiment.

FIG. 8 is an electric block diagram of a second embodiment.

FIG. 9 is a longitudinal sectional view showing a schematic configuration of a conventional image forming apparatus.

FIG. 10 is a longitudinal sectional view illustrating a schematic configuration of a developing device of a conventional image forming apparatus.

FIG. 11 is an operation explanatory diagram illustrating a conventional web winding completion detection.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 image carrier (photosensitive drum) 3 charging roller 4 developing device 10 fixing drum 30 transfer device 31 fixing roller 36 paper passing detection means (discharge sensor) 39 control unit (counting means, comparing means) 40 display means (display circuit) 41 Storage Unit (Non-Volatile Memory) 50 Fixing Roller Cleaning Device 51 Cleaning Web 52 Web Supply Member (Web Supply Roller) 53 Web Winding Member (Web Winding Roller) 55 Winding Drive Unit (Cleaning Web Winding Drive Unit) 60 Rolls Winding completion notice detection means M Winding completion notice detection position P Recording material

Continuation of the front page (56) References JP-A-7-199708 (JP, A) JP-A-1-241584 (JP, A) JP-A-6-124023 (JP, A) JP-A-61-180251 (JP) JP-A-5-232828 (JP, A) JP-A-3-31762 (JP, U) JP-A-3-84857 (JP, U) JP-A-2-62457 (JP, U) JP-A 5-38661 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/20 105 G03G 21/18

Claims (4)

(57) [Claims] A fixing roller for contacting the unfixed toner on a recording material and fixing the unfixed toner on the recording material;
An image forming apparatus provided with a fixing device having a cleaning web that removes offset toner by rubbing against the surface of the fixing roller while being wound by a web winding member from a web supply member; Setting the completion time of winding the cleaning web by the web winding member so as to match the estimated replacement time of the fixing roller, and detecting the completion of winding of the cleaning web. Means for displaying the imminent replacement of the fixing device based on the output of the winding completion notice detecting means, and when the predetermined number of recording materials have been fixed after the output of the winding completion notice detecting means, Display means for prompting the user to replace the fixing device, wherein at least the web supply member, the web take-up member, An image forming apparatus, wherein the cleaning web and the fixing roller are integrally unitized, and the unit is exchangeably mounted on the image forming apparatus main body. 2. A take-up driving means for driving the web take-up member; a paper passing detection means for detecting whether or not a recording material has passed through the fixing device; and an output from the paper passing detection means. Counting means for counting the number of passed sheets of material, storing means for storing the number of counts by the counting means, and comparing means for comparing whether or not the count number has reached a predetermined number; After detecting the upcoming winding of the cleaning web through the notice detection means, until the comparison means detects that the count number has reached a predetermined number,
The image forming apparatus according to claim 1, wherein winding of the cleaning web by the winding driving unit is continued. 3. The image forming apparatus according to claim 2, wherein a driving speed of the winding driving unit is changed according to a type of the recording material. 4. A calculating means for calculating the number of sheets that can be fixed until the winding by the web winding member is completed based on an output of the comparing means, and a storing means for storing the calculation result of the calculating means. 4. The image forming apparatus according to claim 1, wherein the calculation result is sequentially updated and displayed on the display unit.