JP2001242730A - Image forming device - Google Patents

Abstract

(57) Abstract: An image forming apparatus is provided which automatically cleans a dirt on a pressure member at predetermined intervals to prevent a problem due to dirt on the pressure member. A heating member (10, 12, 13) and a pressing member (11) that presses against the heating member to form a heating nip.
And an image heating means for heating the image on the recording material through the recording material P in the heating nip N, and by holding the recording material P in the heating nip N, heating, cooling, and recording the heating nip portion N. An image having a cleaning mode in which the step of transporting the material P to the next cleaning position is defined as one step, and the control is repeatedly performed a plurality of times to sequentially transfer dirt on the peripheral surface of the pressing member to the recording material and remove it. Automatically performing a cleaning mode at predetermined intervals in a forming apparatus.

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 such as an electrophotographic printer, a copying machine, and an electrostatic recording device.

[0002]

2. Description of the Related Art Conventionally, many electrophotographic copiers, printers, and the like employ a contact heating type heat roller fixing system having good thermal efficiency and safety and an energy saving type film heating system as a fixing means. .

A fixing device of a film heating type is disclosed in, for example, JP-A-63-313182 and JP-A-2-15787.
8, 4-44075-44083, 4-20498-
No. 2,049,844, and the like, a heat-resistant film (fixing film), which is a heating rotating body, is brought into close contact with a heating body by a rotating body for pressing (elastic roller) and is slid and conveyed to sandwich the heat-resistant film. A transfer material carrying an unfixed image is introduced into the pressure contact nip formed by the heating element and the pressing member, and is transferred together with the heat-resistant film to be transferred through the heat-resistant film. This is an apparatus for fixing an unfixed image as a permanent image on a transfer material by heat and pressure of a press nip.

In these heat fixing devices, an unfixed image on a recording material is heated and pressed to fix it on the recording material. At this time, all the unfixed toner on the recording paper may be fixed on the recording paper. However, there is actually a so-called offset toner that adheres and remains on the fixing film or the fixing roller side. There are various causes for the offset, such as a cold offset that remains unmelted, a hot offset that remains too hot, and an electrostatic offset that remains due to electrostatic action.
In any case, a part of the offset toner returns to the paper, but the remaining toner transfers to the pressure roller between the papers. This is because the pressure roller has a lower temperature and is inferior in releasability than the fixing film or the fixing roller. The surface of the pressure roller is coated with PFA or the like so that toner stains hardly accumulate, but the toner stains still accumulate gradually. The toner stains accumulated on the pressure roller sometimes become toner dust-like stains at one time, and adhere to the recording material and are discharged, causing a problem or the paper or OHP sheet as the recording material wrapping around the pressure roller. Is a problem.

In order to remove these stains, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 0276, a method of cleaning dirt on the pressure roller by passing a paper having solid black printed on one side thereof with the printing surface facing the pressure roller side is introduced.

In a film-type fixing device, the control of heating, cooling, and step transfer to the next cleaning portion of the pressure roller is performed as one step, and the control is repeatedly performed a plurality of times. A device having a cleaning mode for sequentially transferring dirt to a cleaning paper and removing the dirt is available on the market. These cleaning methods are very effective means because even if the pressure roller becomes dirty, the dirt can be removed.

[0007]

However, since the conventional cleaning by the step conveyance is manually performed by the user, the cleaning is carried out after toner dust or the like is generated on the print paper and the pressure roller becomes dirty. I was

For this reason, the cleaning is performed after the pressure roller is considerably contaminated, and until then, the print paper is stained with toner residue, and in the worst case, the print paper is wrapped around the pressure roller. There was a rolling problem.

On the other hand, although it is possible to ask the user to perform cleaning every fixed number of sheets, the cleaning interval is about once every several thousand sheets. It is very troublesome and impractical for a user to record whether or not a print has been made.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus which automatically cleans the pressure member at predetermined intervals to prevent the problem caused by the contamination of the pressure member.

[0011]

An image forming apparatus according to the present invention is characterized by the following constitution in order to solve the above-mentioned problems.

[1] An image heating means which has a heating member and a pressure member which forms a heating nip by pressing against the heating member, and which heats an image on the recording material by passing the recording material through the heating nip. By holding the recording material in the heating nip, heating the heating nip, cooling, and step-transporting the recording material to the next cleaning position as one step, by repeatedly performing this multiple times, An image forming apparatus having a cleaning mode in which dirt on a peripheral surface of a pressing member is sequentially transferred to a recording material and removed, wherein the cleaning mode is automatically performed at predetermined intervals.

[2]: When the above-described cleaning mode is performed, a recording material having the maximum width is selected based on the size information of the paper supply port from among the recording materials stored in the paper supply port for each size. The image forming apparatus according to claim 1, wherein the image forming apparatus is used for cleaning.

[3]: When the above-described cleaning mode is performed, the formatter of the image forming apparatus waits in an online state, receives the next print signal when the next print signal comes, and performs printing after the cleaning operation is completed. The image forming apparatus according to claim 1 or 2, wherein

[4]: When the above-described cleaning mode is performed, the formatter of the image forming apparatus waits in an online state, and receives a next print signal when a next print signal comes, starts image processing, and performs cleaning. 3. The image forming apparatus according to claim 1, wherein printing is performed after the operation is completed.

[5] The image according to [1], [2], [3] or [4], wherein the predetermined interval is set by the number of sheets on which an image has been formed. Forming equipment.

[6] The cleaning mode is performed after the series of printing operations is completed when the number of sheets on which the image formation has been performed reaches a predetermined number during a series of printing operations. The image forming apparatus according to [5].

[7] The image forming apparatus according to any one of [1] to [6], wherein the predetermined interval is changed according to use conditions.

[8] The image forming apparatus according to any one of [7] to [7], wherein the use condition is an ambient temperature or a print mode.

[0020]

[9]: The heating member includes a heater and a film that slides on the heater, and the pressing member presses the film and presses the heater to form a heating nip. The image forming apparatus according to any one of [1] to [8].

<Operation> According to the configuration [1], the user does not have to perform manual cleaning, and the printer can perform cleaning at predetermined intervals. Further, since the cleaning is automatically performed before the dirt accumulates on the pressure roller, it is possible to prevent the dirt such as toner dust from being generated on the print paper.

According to the configuration [2], when the image forming apparatus has a plurality of paper feed ports, the maximum width size is selected from the size information in each paper feed port and used for automatic cleaning. This makes it possible to perform cleaning as wide as possible with respect to the longitudinal width.

According to the constitutions [3] and [4], the formatter accepts the next print signal while the cleaning mode is being executed while the host computer is online. The received print data is printed after the completion of the cleaning operation. Thus, the host computer does not have to wait during the cleaning operation.

According to the configuration [5], the cleaning timing can be easily determined.

According to the configuration [6], even when the predetermined number of sheets for automatic cleaning is reached during the printing operation, the cleaning can be performed without hindering the printing operation.

According to the constitutions [7] and [8], the degree of contamination of the pressing member varies depending on the use conditions such as the ambient temperature of the image forming apparatus and the print mode (each print interval and the number of prints). Also, by changing the predetermined interval of the automatic cleaning according to these conditions, the required minimum number of cleanings can be achieved.

[0027]

(First Embodiment) FIG. 1 is a schematic sectional view of an image forming apparatus to which the present invention is applied.

In FIG. 1, reference numeral 1 denotes a photosensitive drum serving as an image carrier, which is formed by forming a photosensitive material such as OPC on a cylindrical substrate such as aluminum or nickel.
The surface of the photosensitive drum 1 has a charging roller 2 as a charging device.
Is charged uniformly. Next, the laser beam 3 is turned on / off in accordance with image information to perform scanning exposure, and an electrostatic latent image is formed on the photosensitive drum 1. This electrostatic latent image is developed by the developing device 4 and visualized. As a development method, a jumping development method or the like is used, and in many cases, a combination of image exposure and reversal development is used.

The recording material (paper) P is taken out of the cassette 26 by the paper feed roller 22 and sent to the registration roller 24. The paper P is supplied to a transfer nip m formed by the photosensitive drum 1 and the transfer roller 5 in synchronization with the toner image formed on the surface of the photosensitive drum 1 by the registration roller 24. In the transfer nip portion m, the toner image on the photosensitive drum 1 is transferred to the paper P by the action of a transfer bias from a power supply (not shown). The paper P holding the toner image is conveyed to the fixing device 6 and is heated and pressed at the nip N of the fixing device 6 to fix the toner image T on the paper P. The sheet is discharged out of the apparatus by the sheet discharge roller 28. On the other hand, the transfer residual toner remaining on the photosensitive drum 1 after the transfer is removed from the surface of the photosensitive drum 1 by the cleaning device 7.

FIG. 2 is a schematic sectional view of a film heat fixing device as an example of a fixing device to which the present invention is applied. Hereinafter, the configuration and operation will be described.

In FIG. 2, reference numeral 10 denotes a heat-resistant film (fixing film) in the form of an endless belt, which is fitted around a semicircular film guide member (stay) 13 with a margin in the circumferential length. I have.

The film 10 has a total thickness of 100 μm in order to reduce the heat capacity and improve the quick start property.
m or less, and 60 μm in this embodiment. Single-layer film of PTFE, PFA, PPS etc. with heat resistance, release property, strength, durability, etc., or PTFE, P on the film surface of polyimide, polyamide imide, PEEK, PES etc.
It is a composite layer film coated with FA, FEP or the like as a release layer.

Reference numeral 12 denotes a ceramic heater, which is formed by sequentially forming a heating element on which a heating paste is printed on a ceramic substrate, and a glass coating layer for protecting the heating element and ensuring insulation. Heat is generated by passing a power-controlled AC current through the body. A chip thermistor 14 for detecting the temperature of the heater 12 is adhered to the back of the ceramic substrate, and a temperature control circuit 32 controls a heater driving unit 33 based on the detected temperature of the chip thermistor 14, The power control is performed to maintain the heater temperature at the target temperature (print temperature). Reference numeral 11 denotes a pressing roller as a pressing member, which is a rotating body having an elastic layer formed of heat-resistant rubber such as silicone rubber on a cored bar, or an elastic layer made of silicone rubber. PFA, PTFE, FE
A heat-resistant release layer made of a fluorine resin such as P may be formed. The pressure roller 11 is pressed against the heating member by a spring (not shown), and is rotationally driven by a motor M controlled by a drive circuit 31. The paper P and the fixing film 10 are transported and driven by the rotation of the pressure roller 11. It is configured to be rotated.

When the image forming apparatus receives the print signal,
A pre-rotation operation, which is a preparation stage before printing, starts. At this time, energization of the heater of the fixing device is started to start up the fixing device.

In the present embodiment, the fixing device is started up to 170 ° C. in a start-up time of about 5 seconds, and the above-described various image forming operations are performed in accordance with this timing. P is transported to the fixing device 6. While the paper P is being conveyed to the fixing nip N, the temperature of the fixing device 6 is further increased to reach a fixing temperature control temperature of 190 ° C. during printing, and the fixing operation is performed.

The unfixed toner image T is supplied to a heating unit (film 10, stay 13 and ceramic heater 1) of the fixing device 6.
2) Pressing nip N formed by the pressing roller 11
The paper P is heated and pressurized inside and is fixed on the paper P, and the paper P after the fixing is discharged out of the apparatus.

When a large amount of printing is performed using such an image forming apparatus, toner stains adhere to the surface of the pressure roller. For example, when 20,000 sheets of paper P having a rough surface and poor fixability, called bond paper, are continuously printed, the toner stain adheres to the pressure roller 11, and
After the 000th sheet, toner scraps can be seen on the printed paper.

In this embodiment, in order to prevent such contamination, a cleaning mode for automatically performing a cleaning operation by step feed every 15,000 sheets is provided.

In the cleaning mode, the number of sheets on which an image has been formed is counted by the number counter of the cleaning controller 30, and the drive is started when the total number of sheets from the start of use or from the previous cleaning reaches a predetermined number (15,000 in this example). This is automatically performed by controlling the circuit 31, the temperature control circuit 32, and the like. When the cleaning mode is performed, first, the paper P set in the paper feed port (cassette) 26 is fed and transported to the fixing device 6. When the leading edge of the sheet comes out of the fixing nip N, the sheet conveyance is temporarily stopped, and thereafter, the cleaning operation by the step conveyance is started. The timing at which the leading edge of the paper leaves the fixing nip portion N was detected by turning on a sheet discharge sensor downstream of the fixing nip portion.

In the cleaning operation, as shown in FIG. 3, first, the conveyance of the paper P is stopped (FIG.
The temperature is controlled at 80 ° C. to melt the toner stain Ta on the pressure roller located in the nip portion N, and while the paper P is stopped, the heating by the heater 12 is turned off to cool naturally for 1 second, and the toner stain Ta is removed. After being fixed to the paper P (FIG. 3 (b)), the paper P is transported for 50 milliseconds to cause a step transport to the next cleaning position (the paper transport motor is turned only momentarily), and the toner stain Ta is pressed. At the same time as peeling off from the roller surface, the next cleaning portion 11a on the pressure roller is positioned at the nip portion N (FIG. 3C). This is repeated as a required number of times as one step.

In the present embodiment, the motor for transporting paper is
When turned on for 0 millisecond, the paper is transported by about 5 mm. Since the fixing nip width is 6 to 7 mm, by repeating this step operation, it is possible to sequentially clean the pressure roller without any gap.

The outer diameter of the pressure roller in the present embodiment is φ24 and is about 76 mm around one circumference. Since the step operation is performed 32 times, the distance of the step conveyance is about 160 mm, and the pressure roller can be cleaned for two turns. After that, the cleaning paper P is discharged again at the normal paper conveyance speed, and the cleaning mode (cleaning operation) ends.

In the cleaning by the step transport, the heating is performed while the paper transport is stopped, so that the toner stain Ta attached to the pressure roller 11 is completely melted. Further, the toner stain Ta melted from the pressure roller 11 is cooled while being adhered to the cleaning paper P, and is conveyed after being fixed. Since the toner stain Ta is once completely melted and adhered to the cleaning paper P as described above, the paper P is simply a white paper and has a sufficient cleaning effect, and a toner image is not provided on the pressure roller surface side as in the conventional example. May be. The toner stain Ta on the pressure roller 11 adheres to the surface of the cleaning paper P opposite to the printing surface and is cleaned.

In the pressure roller cleaning at a normal transport speed similar to that in the conventional printing without step transport or the cleaning with a slow transport speed, the toner adhered on the pressure roller cannot be completely melted.
A sufficient cleaning effect could not be obtained unless auxiliary means such as forming a toner image on the pressure roller surface side were provided. However, since this toner image is required on the side opposite to the printing surface, it is impossible to automatically perform cleaning unless the image forming apparatus is capable of performing double-sided printing.

That is, since the cleaning is performed by the step transfer, the automatic cleaning can be performed.

In this embodiment, a predetermined interval, ie, 150
By automatically executing the cleaning mode for every 00 sheets, the pressure roller 11 is cleaned before toner dust is generated on the paper due to contamination of the pressure roller, and the print paper is wound around the pressure roller 11. .

On the other hand, when the cleaning is not automatically performed, a cycle in which the user notices dirt on about 20,000 sheets and performs cleaning is repeated, so that the print paper to which toner dust adheres is output before cleaning. Problem has occurred.

As described above, according to the present embodiment, the user does not have to perform manual cleaning, and the printer can reliably perform cleaning at predetermined intervals. Further, since the cleaning is automatically performed before the dirt accumulates on the pressure roller, it is possible to prevent the problem that dirt such as toner dust is generated on the print paper.

(Second Embodiment) In this embodiment, in an apparatus having a plurality of paper feed ports in which the sizes of the recording materials to be stored are different, the paper size information stored in each paper feed port when the cleaning mode is performed. , A paper size having the maximum width is selected, and cleaning is started using the recording material having the maximum width.

FIG. 4 is a schematic diagram showing the configuration of the image forming apparatus.
The configuration is the same as that of the first embodiment except for the sheet feeding portion, and a description thereof is omitted.

The image forming apparatus according to the present embodiment has three paper feed ports (paper feed cassettes). LTR size (approximately 216 mm in width) in paper supply port 1, A4 size (approximately 210 mm in width) in paper supply port 2, and A5 size (approximately 148 in width)
mm) paper is set. These paper sizes are transmitted to the cleaning control unit 30 of the printer engine by reading the paper size information Ps of each paper feed port with the sensor 30a. In these paper sizes, the LTR size is the paper size of the maximum width. Therefore, when the cleaning mode is performed, the cleaning control unit 30 operates the paper feed roller 22 of the paper feed port 1.
Is selectively driven to feed LTR size paper.

Incidentally, the maximum sheet passing width of the image forming apparatus of this embodiment is LTR size 216 mm.

In the step transport cleaning, the cleaning is performed by transferring the dirt on the pressure roller 11 to the cleaning paper P, so that only the width of the cleaning paper P can be cleaned. In this embodiment, since the LTR size is selected, the longitudinal direction of the pressure roller 11 (the recording material width direction) is used.
Dirt could be removed over the entire area.

On the other hand, in this printer, B
5 sizes (about 182 mm in width), A4 size (about 210 mm in width) in paper feed port 2, and A5 size (about 14 mm in width)
When the paper P of 8 mm) is set, the A4 size is the paper having the maximum width, so the A4 size of the paper feed port 2 is selected and the step transport cleaning is performed.

A COM10 size envelope (width of about 104.8 mm) is provided in the paper supply port 1, a B5 size (about 182 mm in width) is provided in the paper supply port 2, and an A5 size (about 148 m in width) is provided in the paper supply port 3.
If the paper m) is set, the B5 size is the paper having the maximum width, so the B5 size of the paper feed port 2 is selected and the step transport cleaning is performed. In this case B
In the case of 5 sizes, a non-sheet passing portion of about 17 mm occurs at both ends, which is smaller than the maximum sheet passing width of 216 mm of the printer. These ends will not be cleaned,
If the user selects the maximum width among the paper types used, it can be said that the necessary longitudinal range can be cleaned. That is,
This is because, for a user who uses only the B5 size or a smaller size, the pressure roller 11 is also contaminated only up to the width of the B5 size, so it can be said that cleaning with the B5 size is sufficient.

As described above, when the cleaning is performed, the paper size having the maximum width is selected from the paper feeding ports, and the step conveyance cleaning operation is started using the selected paper size. A proper range can be cleaned accurately.

(Third Embodiment) In the present embodiment, even when the step-conveying cleaning operation is being performed, the print signal is output while the formatter (the portion that receives the print signal from the host computer or the like and performs image development processing) is online. It is characterized in that the print that has been received after the reception and cleaning operation is completed is executed. The other configuration is the same as that of the first embodiment, and the description will not be repeated.

Conventionally, during a cleaning operation, the formatter goes off-line and does not accept a print signal, so that the user cannot send a print command while the printer is performing a cleaning operation. In recent years, printers are used by connecting to a network, so that many users often share one printer. Therefore, if the printer goes offline, it affects many users. In particular, the printer cannot be used for about two minutes during which the cleaning operation is automatically performed, which is inconvenient.

In this embodiment, even when the cleaning operation is being performed, the formatter is in the online state, so that such a problem does not occur, and the user can send a print command from the host computer or the like as usual.

Although the actual printing operation is performed after the cleaning operation is completed, since the image processing such as image development of the print data received by the formatter can be performed in advance, the printing time is also advantageous.

However, after all, if the user can issue a print command, the computer and the printer will carry out the printing work, and the user can print the printed paper at a convenient time. Is very effective as a printer function.

As described above, according to this embodiment, the host computer does not have to wait for the next print signal during the cleaning operation, and the convenience is improved.

In contrast to this embodiment, during the cleaning operation, the formatter is kept on-line, and when the next print signal is received, the cleaning operation is immediately stopped and the cleaning paper P is removed. It is also possible to adopt a configuration in which the sheet is ejected at the speed described above, and the cleaning operation is performed again after printing is completed (immediately or after an idle state for a predetermined time).

(Fourth Embodiment) In the present embodiment, when a predetermined number of sheets for performing the cleaning mode is reached during execution of a series of printing operations, the cleaning operation is not immediately performed, and the series of printing operations is completed. After that, the cleaning operation is performed.

For example, in a printer in which automatic cleaning is performed every 10,000 sheets, if a 10,000th sheet to be subjected to automatic cleaning comes while a continuous print job is being executed, the print job is terminated. Wait for cleaning to run. When the print job is completed and the printer is once in the standby mode, the cleaning operation is executed unless the next print signal is received.

However, when a predetermined number of sheets for performing the automatic cleaning comes during the printing operation, and when a series of printing operations are being performed, but the paper runs out of paper during printing, or when the printing is interrupted due to a paper jam or the like. , The printing operation is continued after the paper P is supplied and the jam is removed and the recovery is performed, and the cleaning operation is performed after all the printing is completed. This enables the user to obtain the print output result earlier.

As described above, according to the present embodiment, cleaning can be performed without interrupting the printing operation.

(Fifth Embodiment) In the present embodiment, the first
The embodiment is characterized in that the cleaning execution interval is changed depending on the printer use condition of the user, that is, the print mode or the printer use environment. FIG. 6 shows a schematic diagram of the present embodiment.

In the present embodiment, the cleaning interval is changed according to the ambient temperature of the environment in which the printer is used. Reference numeral 35 in FIG. 6 denotes a thermistor for detecting the outside air temperature of the printer, which is attached to a cooling fan intake port on the side of the printer. When the outside air temperature detected by the outside air temperature detection thermistor is 20 ° C. or higher, the automatic cleaning is performed every 10,000 sheets, and when the outside air temperature is lower than 20 ° C., the automatic cleaning is performed every 5,000 sheets.

When the outside air temperature is low, the temperature of the pressure roller is also low because the temperature of the paper is low, and the toner tends to adhere to the pressure roller 11.

A printing experiment was performed with the apparatus of the present embodiment in a 10 ° C. environment. When printing is continued without performing the cleaning operation, dirt and dust on the pressure roller 11 starts to appear in the print image from about 7,000 sheets. In a normal environment (approximately 23 ° C.), an image defect seen around 20,000 sheets occurred at a very early number.

According to the present invention, by optimizing the cleaning interval according to the printer operating environment temperature, even if the printer is used in a low temperature environment, the cleaning is performed for every 5,000 sheets before dirt is generated. The effect was obtained that the problem due to the pressure roller contamination did not occur.

It is also effective to change the cleaning environment depending on the print mode, that is, the difference between continuous printing and intermittent printing.

In continuous printing, since the pressure roller 11 is warmed, the toner stain Ta does not easily adhere to the pressure roller 11.

On the other hand, in intermittent printing, the longer the intermittent time, the lower the temperature of the pressure roller, and the more the toner stain Ta tends to adhere.

Thus, for example, a method is conceivable in which the number of image formations to be added to the number counter of the cleaning control unit 30 is changed according to the print mode. In either case, cleaning is executed when the number of sheets reaches 10,000, but in continuous printing, +1 is added to the number of sheets each time one sheet is printed. Thus, cleaning is performed every 10,000 sheets.

In intermittent printing for one minute from the previous print, +2 is added to the number counter every time one sheet is printed. Thus, cleaning is performed every 5,000 sheets.

In the case of intermittent printing for 10 minutes after the previous print, the number of sheets is incremented by +11 each time one print is made.
to add. Thus, cleaning is performed every 909 sheets.

That is, in the case of intermittent printing for n minutes from the previous print, n + 1 is added to the number counter every time one sheet is printed, and a constant value is added after the upper limit (for example, 10 minutes).

Note that the above is an example, and the present invention is not limited to this, and the cleaning interval may be controlled based on any use condition as long as the degree of contamination of the pressure roller 11 can be determined.

As described above, according to the present embodiment, the predetermined interval for the automatic cleaning is changed according to the use conditions such as the ambient temperature of the printer and the print mode (each print interval and the number of prints), so that the necessary minimum cleaning is performed. It can be done in a number of times.

[0082]

As described above, according to the present invention, there is provided an image forming apparatus in which a problem due to the contamination of the pressure member is prevented by automatically cleaning the contamination of the pressure member at predetermined intervals. can do.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a main part of the first embodiment.

FIG. 3 is an explanatory diagram of a cleaning operation.

FIG. 4 is a schematic diagram of an image forming apparatus according to a second embodiment of the present invention.

FIG. 5 is an explanatory view of a main part of a second embodiment.

FIG. 6 is a schematic diagram of an image forming apparatus according to a fifth embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photosensitive drum 2 charging roller 3 laser beam 4 developing device 5 transfer roller 6 fixing device 7 cleaning device 10 fixing film 11 pressure roller 12 ceramic heater 14 chip thermistor 26 paper feed port (cassette) N nip portion P paper (recording material) T Toner image Ta Toner stain

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) 2H027 DA11 DA12 DA45 DA46 DC19 EA09 ED17 ED25 ED27 ED30 EF06 EF11 EF13 HB02 HB05 HB19 2H033 AA08 AA09 AA35 BA08 BA27 BA29 BA48 BE03 9A001 BB06 HH34 JJ35 KK42

Claims (9)

[Claims] An image heating means for heating an image on a recording material by passing a recording material through the heating nip; Pressing the recording material into the heating nip, heating and cooling the heating nip, and step-transporting the recording material to the next cleaning position as one step. An image forming apparatus having a cleaning mode for sequentially transferring dirt on a peripheral surface of a member to a recording material and removing the same, wherein the cleaning mode is automatically performed at predetermined intervals. 2. When the cleaning mode is performed, a recording material having a maximum width is selected based on size information of a paper supply port from among the recording materials stored in the paper supply port for each size, and cleaning is performed. 2. The method according to claim 1, wherein
An image forming apparatus according to claim 1. 3. When executing the cleaning mode, the formatter of the image forming apparatus waits in an online state, receives a print signal when a next print signal comes, and executes printing after the cleaning operation is completed. The image forming apparatus according to claim 1, wherein: 4. When executing the cleaning mode, the formatter of the image forming apparatus waits in an online state, and when a next print signal comes, receives the print signal and starts image processing, and ends the cleaning operation. The image forming apparatus according to claim 1, wherein printing is performed later. 5. The image forming apparatus according to claim 1, wherein the predetermined interval is set by the number of sheets on which an image has been formed.
Or the image forming apparatus according to 4. 6. The cleaning mode according to claim 5, wherein if the number of sheets on which the image formation has been performed reaches a predetermined number during a series of printing operations, the cleaning mode is executed after the series of printing operations is completed. The image forming apparatus as described in the above. 7. The image forming apparatus according to claim 1, wherein the predetermined interval is changed according to use conditions. 8. The image forming apparatus according to claim 7, wherein the use condition is an ambient temperature or a print mode. 9. The heating member includes a heater and a film that slides on the heater, and the pressing member presses the film and presses the heater to form a heating nip. The image forming apparatus according to any one of claims 1 to 8.