JP2001265152A - Cleaning method and cleaning device for fixing machine for image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an efficient cleaning method for a fixing machine, capable of responding to a request of miniaturizing a device, because it does not occupy a special space in an image forming device, besides, without increasing cost, and to provide a cleaning device. SOLUTION: For the cleaning method for the fixing machine 28 for the image forming device, when a recording sheet S in carrying is held by both of a pair of fixing rollers 14 for the fixing device 28 and an upstream side recording sheet feeding device 16 arranged on the upstream side of the fixing device 28, cleaning operation is performed by making a recording sheet S carrying speed by the device 16 lower than a recording sheet S carrying speed by the pair of fixing rollers 14, and also, making a recording sheet S carrying force by the device 16 stronger than a recording sheet S carrying force by the pair of fixing rollers 14, so as to generate slippage between the pair of fixing rollers 14 and the recording sheet S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for cleaning a fixing device in an electrophotographic image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art In an electrophotographic image forming apparatus or the like, a toner image formed by electrostatically adsorbing toner on recording paper is fixed to a recording sheet by applying heat and pressure by a fixing device. You.

A fixing device generally has a heat fixing roller having heating means and a pressure fixing roller for applying pressure, and a recording paper is passed between the heat fixing roller and the pressure fixing roller. The fixing is performed during the operation.

At this time, a part of the toner and the generated paper dust adhere to the heat-fixing roller and the pressure-fixing roller, and the fixing is not performed well. Cleaning is performed regularly or irregularly.

Conventionally, as a roller of the fixing device, a method of cleaning a roller surface by sliding a dedicated cleaning roller or a cleaning pad, a method of passing a dedicated cleaning sheet between rollers, and the like are generally used.

However, in the case where a dedicated device such as the above-described system using a cleaning roller or a cleaning pad is provided, a space for the device is required, and thus the image forming apparatus can be downsized as required. It's getting harder.

Further, the cleaning roller or the cleaning pad used therefor has a problem that it needs to be replaced by an expert trader such that it is replaced at appropriate intervals because of wear and dirt.

On the other hand, in the case of using a cleaning sheet, although it is not necessary for a specialized trader, the burden on the user side is large, such as purchasing the cleaning sheet, loading the cleaning sheet into the image forming apparatus and performing the cleaning work by the user himself. Problem.

[0009]

SUMMARY OF THE INVENTION The present invention does not occupy a special space in an image forming apparatus, thereby meeting demands for miniaturization, and increasing efficiency without increasing costs. It is an object to provide a cleaning method or apparatus for an improved fixing device.

[0010]

According to the present invention, there is provided a fixing device cleaning method and a cleaning device which solve the above-mentioned problems by the following means. That is, in the cleaning method of the fixing device in the image forming apparatus according to the first aspect of the invention, the recording sheet to be conveyed is fed to a pair of a fixing rotator of the fixing device and an upstream recording sheet disposed upstream of the fixing device. In a state where the recording sheet is held by both the apparatus, the speed at which the upstream recording sheet feeding device conveys the recording sheet is slower than the speed at which the fixing rotating body pair conveys the recording sheet, and The conveying force for conveying the recording sheet by the upstream recording sheet feeding device is made stronger than the conveying force for conveying the recording sheet by the fixing rotator pair, so that the fixing rotator pair and the recording sheet This is a cleaning method for cleaning the pair of fixing rotators by causing slippage therebetween.

According to a second aspect of the present invention, there is provided a method for cleaning a fixing device in an image forming apparatus, wherein a conveyed recording sheet includes a pair of fixing rotators of the fixing device and a downstream feed rotator disposed downstream of the fixing device. In the state where the pair is held by both the pair, the speed at which the downstream-side feed rotator pair conveys the recording sheet is faster than the speed at which the fixing rotator pair conveys the recording sheet, and The conveying force for conveying the recording sheet by the pair of downstream-side feed rotators is made stronger than the conveying force for conveying the recording sheet by the fixing rotator pair, and the conveying force between the fixing rotator pair and the recording sheet is increased. This is a cleaning method for cleaning the pair of fixing rotators by causing slippage.

According to a third aspect of the present invention, there is provided a method of cleaning a fixing device in an image forming apparatus, wherein a recording sheet to be conveyed includes a pair of fixing rotators of the fixing device and a recording sheet stopping means disposed upstream of the fixing device. When transported to a position straddling both, the force of the recording sheet stopping means to stop the recording sheet is stronger than the transporting force of the fixing rotator pair to transport the recording sheet, and,
While operating the recording sheet stopping means to stop the recording sheet, the conveyance of the fixing rotating body pair is continued,
A cleaning method for cleaning the fixing rotator pair by causing a slip between the fixing rotator pair and the recording sheet.

According to a fourth aspect of the present invention, there is provided a method for cleaning a fixing device in an image forming apparatus according to the first to third aspects of the present invention, further comprising: This is a cleaning method in which a recording sheet having the largest possible width is used.

A cleaning device for a fixing device in the image forming apparatus according to a fifth aspect of the present invention is provided in the fixing device, and includes a fixing rotator pair for conveying a recording sheet while fixing the recording sheet; Provided upstream of the pair,
Recording sheet stopping means for stopping the conveyance of the recording sheet, wherein when the conveyed recording sheet is conveyed to a position straddling both the fixing rotator pair and the recording sheet stopping means, The recording sheet stopping means is for stopping the conveyance of the recording sheet with a force stronger than the conveyance force for conveying the recording sheet by the fixing rotator pair, and the fixing rotator pair performs the recording at this time. A cleaning device for continuously conveying a sheet, wherein the pair of fixing rotators is cleaned by slippage generated between the pair of fixing rotators and the recording sheet.

A cleaning device for a fixing device according to a sixth aspect of the present invention is the cleaning device according to the fifth aspect, wherein
The cleaning device uses a recording sheet having a maximum width that can be handled by the image forming apparatus when cleaning the fixing device.

In these inventions, the recording sheet slides with respect to the fixing rotator pair of the fixing device according to the above configuration, so that the fixing rotator pair is wiped by the recording sheet from the viewpoint of the fixing rotator. With such an operation, cleaning is performed on the fixing rotating body pair and, consequently, the fixing device.

As described above, an efficient fixing device can be provided without occupying a special space in the image forming apparatus, thereby meeting demands for downsizing, and without increasing costs. A cleaning method or apparatus.

In the fourth and sixth aspects, the maximum width of the fixing device is cleaned by using the recording sheet having the maximum width usable in the image forming apparatus.

[0019]

FIG. 1 is an explanatory view schematically showing an example of an embodiment of an image forming apparatus to which the present invention is applied.

Examples of the image forming apparatus include an electrophotographic copying machine, a printer, and a facsimile machine. Such an image forming apparatus 1 includes a photosensitive drum 21,
The static eliminator 22 and the photosensitive drum 21 disposed therearound
, A charging device 24, an exposure device 25, a developing device 26, and a transfer device 27. The photoreceptor drum 21 is composed of a conductive (for example, metal) cylinder and a photoreceptor layer on the outer periphery of the cylindrical surface. The photoreceptor layer usually has an insulating property (when light is not irradiated), It is a material that exhibits conductivity when irradiated.

When the photosensitive drum 21 rotates as indicated by an arrow and passes in front of a charging device 24 disposed around the photosensitive drum 21, the charging device 24 charges the surface of the photosensitive layer of the photosensitive drum 21. The charged photosensitive layer is the photosensitive drum 2
When the light reaches the front surface of the exposure device 25 with the rotation of 1, the light corresponding to the image to be formed is emitted. This exposure apparatus 2
Reference numeral 5 denotes a photosensitive drum 2 that optically guides image light of a document.
Even if it is of an analog type that forms an image on the surface of one, a laser, an LED or the like is used based on image data obtained in advance or image data read by a scanner.
For example, a digital type that irradiates the light emitted by the above method for each pixel may be used.

When the photoreceptor layer is irradiated with light, the photoreceptor layer develops conductivity, so that the charged charges on the surface move to a conductive (metal or the like) cylinder, and the surface of the photoreceptor layer is exposed to light. Charge is lost.

The exposure device 25 irradiates the photosensitive layer of the photosensitive drum 21 with light corresponding to the image to be formed.
There is a state where the charged state differs between the light-irradiated portion and the non-irradiated portion, that is, a latent image that cannot be visually recognized is formed.

The portion where the latent image is formed is the photosensitive drum 21
Is moved to the front of the developing device 26 by the rotation of. The developing device 26 supplies the charged powdery toner to the surface of the photosensitive drum 21. The supplied toner is electrostatically attracted to the surface of the photoreceptor layer according to the charged state (that is, the latent image), and an image that is visually captured by the toner is formed (developed).
Is done.

The toner image thus formed is carried to the transfer device 27 as the photosensitive drum 21 rotates.
On the other hand, the recording sheets S stacked on the sheet cassette 32
Is taken out from the uppermost portion and transported to the transfer device 27 in synchronization with the movement of the toner image due to the rotation of the photosensitive drum 21. In the transfer device 27, an electrostatic field is applied from the back of the recording sheet S, and the toner image moves from the surface of the photoconductor layer onto the recording sheet by the electrostatic field. Thus, the transfer is performed.

The recording sheet S to which the toner image has been transferred is conveyed to a fixing device 28, where it is fixed, and a sheet discharging roller pair 9 is formed.
Is discharged to the paper discharge tray 33 through

On the other hand, the photosensitive drum 21 on which the toner image has been transferred to the recording sheet S continues to rotate further, and the charged charges remaining on the surface of the photosensitive layer are removed by the charge removing device 22. Then, the surface of the photosensitive drum 21 on which a small amount of toner is left is cleaned to prepare for charging for the next cycle.

Since the recording sheet S to which the toner has been transferred by the transfer device 27 is only electrostatically attracted,
As the charge dissipates over time, the adsorption force also disappears.
Therefore, the fixing device 28 fixes the toner (image) on the recording sheet S by applying heat and pressure.

FIG. 2 is a sectional view of a principal part for schematically explaining the first embodiment of the present invention.

The fixing device 28 includes a fixing heating rotator 11 having a heating means such as a halogen lamp therein, a fixing pressing rotator 12 pressed from below by a biasing means (not shown), and other surfaces of the fixing heating rotator 11. And an oil application device (not shown) for applying oil as a release agent. Further, the fixing heating rotator 11 and the fixing pressing rotator 12 constitute a fixing rotator pair 14.

In this embodiment, first to third
In the embodiment of the present invention, the present invention will be described based on a fixing device using the fixing heating rotator 11, but other types of the fixing device requiring cleaning, for example, a rotator corresponding to the fixing heating rotator 11 To a known belt-type fixing device that applies heat to the recording paper by heating the belt (the belt can also be called a fixing rotating body in such a case). It is also applicable.

In this case, it is understood that a fixing belt is stretched over the fixing heating rotator 11 and that the fixing belt is to be cleaned.

Although the example shown in FIG. 1 is shown for a monochrome image forming apparatus, the invention disclosed in this specification also applies to a fixing device in a color image forming apparatus of a tandem type, a four cycle type or the like. It goes without saying that a certain cleaning method or cleaning device is applicable.

Further, as will be apparent from the matters described later, the fixing device 28 does not include cleaning members such as a cleaning roller and a cleaning pad provided in a normal fixing device.

The fixing pressure rotating body 12 is a fixing heating rotating body 11
A nip portion for conveying the recording sheet S is formed in cooperation with. An upstream recording sheet feeding device 16 including an upstream feeding roller pair 13 for conveying the recording sheet is installed upstream of the fixing device 28. The upstream recording sheet feeding device 16 may be provided as an independent device, or may be a timing roller pair for adjusting the reference of the leading end of the recording sheet S, a transfer roller pair for performing transfer, or the like.
A device included in the image forming apparatus can be used from the beginning. Here, the feed fixing device 15 is configured by the upstream recording sheet feeding device 16 and the fixing device 28.

When the image forming apparatus 1 is set to the cleaning mode in order to clean the fixing rotator pair 14 of the fixing device 28, the image forming apparatus 1
The recording sheet S set in the printer 2 is fed. The leading end of the fed recording sheet S is the upstream recording sheet feeding device 1
6, the recording sheet S is simultaneously held (gripped) by the upstream recording sheet feeding device 16 and the nip portion of the fixing device 28 when reaching the nip portion of the fixing rotating body pair 14 of the fixing device 28. It is in a state of being left.

At this time, the speed at which the upstream recording sheet feeding device 16 conveys the recording sheet S is lower than the conveying speed of the fixing device 28, and the conveying force of the upstream recording sheet feeding device 16 is reduced by the fixing device 28. Is set to be stronger than the transfer force. This is because the recording sheet S is pulled downstream by the fixing device 28, but the upstream recording sheet feeding device 16
Does not feed the recording sheet S at a speed corresponding to this, and furthermore, since the conveying force of the fixing device 28 is weaker, the relative position between the recording sheet S and the fixing rotating body pair 14 of the fixing device 28 is relatively low. Means that slippage occurs.

For this reason, since the recording sheet S passes through the fixing rotator pair 14 with relative sliding, the surface of the fixing rotator pair 14 is wiped by the recording sheet S, that is, the fixing rotator pair 14 Will be cleaned.

As the recording sheet S fed in the cleaning mode, the widest sheet that can be handled by the image forming apparatus 1 is used so that the entire width of the fixing device 28 can be cleaned. Therefore,
The recording sheet S is fed from the one containing the widest recording sheet S among the plurality of sheet feeding cassettes 32 in FIG.

In order to prevent the recording sheet S from being torn, the conveying force of the fixing device 28 must be set to be weaker than the strength of the recording sheet S against pulling.

FIG. 3 is a sectional view of an essential part for schematically explaining a second embodiment of the present invention. Note that the reference numerals and member names used in FIG. 2 are commonly used as long as there is no problem, and duplicate descriptions are omitted unless particularly necessary.

Downstream of the fixing device 28, a pair of downstream feed rotating members 9 for transporting the recording sheet S is provided.
The downstream feed rotary member pair 9 may be provided as an independent device, or may be an image forming device 1 such as a discharge roller pair 9 for discharging the fixed recording sheet S to the discharge tray 33. It is also possible to use a device provided by the company. Here, the feed fixing device 15 is configured by the fixing device 28 and the downstream-side feed rotary member pair 9.

When the image forming apparatus 1 is set to the cleaning mode in order to clean the fixing rotator pair 14 of the fixing device 28, the image forming apparatus 1 removes the recording sheet S set in the sheet cassette 32. Feed paper. When the leading end of the fed recording sheet S passes through the fixing device 28 and reaches the downstream feed rotating body pair 9, the recording sheet S passes through the nip portion of the fixing device 28 and the downstream feed rotating body pair 9. At the same time, they are held (gripped).

At this time, the speed at which the pair of downstream feed rotators 9 conveys the recording sheet S is faster than the speed of conveyance of the fixing device 28, and the conveyance force of the pair of downstream feed rotators 9 is the fixing device 2.
8 is set stronger than the transfer force. This is because the recording sheet S is pulled downstream by the downstream-side feed rotator pair 9 but the fixing device 28 does not feed the recording sheet S at a speed corresponding to this, and furthermore, the fixing device 28
Is weaker, the recording sheet S and the fixing device 28
Means that slippage occurs relatively between the pair of fixing rotators 14.

For this reason, since the recording sheet S passes through the fixing rotator pair 14 with relative sliding, the surface of the fixing rotator pair 14 is wiped by the recording sheet S, that is, the fixing rotator pair 14 Will be cleaned.

At this time, the recording sheet S having the maximum width is used as in the first embodiment.

FIG. 4 is a sectional view of an essential part for schematically explaining a third embodiment of the present invention. Note that the reference numerals and member names used in FIG. 2 are commonly used as long as there is no problem, and duplicate descriptions are omitted unless particularly necessary.

In this embodiment, the conveyed recording sheet S
The paper feed guide 18 and the paper feed guide 18
Sheet stopping means 17 including a recording sheet pressing means 19 for pressing the recording sheet S toward the fixing device 28.
Is provided on the upstream side.

When the image forming apparatus 1 is set to the cleaning mode in order to clean the fixing rotator pair 14 of the fixing device 28, the image forming apparatus 1 removes the recording sheet S set in the sheet cassette 32. Feed paper. When the leading end of the fed recording sheet S passes through the not-yet-operated recording sheet stopping means 17 and reaches the nip portion of the fixing rotator pair 14 of the fixing device 28, the recording sheet stopping means 17 is turned off. It operates to fix the recording sheet S. At this time, the fixing device 28 keeps rotating. However,
The force by which the recording sheet stopping means 17 fixes the recording sheet S is set stronger than the conveying force of the fixing device 28, and the recording sheet S is pulled downstream by the fixing device 28, but the recording sheet S is Because it is fixed,
Slip occurs relatively between the recording sheet S and the fixing rotating body pair 14 of the fixing device 28. For this reason, the fixing rotator pair 1
The surface of No. 4 is wiped by the recording sheet S, that is, the fixing rotator pair 14 is cleaned.

At this time, as the recording sheet S, the recording sheet having the maximum width is used as in the first embodiment.

As shown by the three embodiments, in the present invention, the surface of the fixing rotator pair 14 is wiped by the slip between the fixing rotator pair 14 and the recording sheet S to perform cleaning. This cleaning is performed by the image forming apparatus 1.
The normal recording sheet S is used, and no special cleaning sheet is required. However, at the time of cleaning, a special cleaning sheet made for that purpose is loaded into the image forming apparatus 1, and
Although it is naturally possible to perform the cleaning by this.

Although FIGS. 1 to 4 have been described more simply to assist the understanding of the present invention, the members constituting the image forming apparatus and the fixing device, the devices as elements, and the relative arrangement of the means are described. The positional relationship, orientation, and the like can be freely arranged without being limited to these drawings as long as each function is performed.

Further, such cleaning may be performed periodically by the timer in the image forming apparatus 1 or may be performed every time the number of prints is counted by the number counter. It is also possible to appropriately issue a cleaning command.
Further, the image forming apparatus 1 may be provided with an apparatus for monitoring the dirt on the fixing rotator pair 14, so that the mode is automatically switched to the cleaning mode when the dirt exceeds a certain level. In any case, by appropriately performing the cleaning, the life of the fixing device 28 can be extended.

Further, there is no need to provide a dedicated cleaning device or cleaning member in the image forming apparatus 1 (first and second embodiments), or the recording sheet stopping means 17 which is an extremely simple and small device can be used. Since it is sufficient to provide the fixing device (in the case of the third embodiment), the fixing device 28 and the image forming apparatus 1 using the same can be reduced in size.

Further, since there is no need to purchase a dedicated cleaning sheet, the burden on the user can be reduced.

[0056]

The cleaning method and the cleaning device for a fixing device according to the present invention can be cleaned without occupying a special space in the image forming apparatus, and can meet the demand for miniaturization. Becomes possible. Further, it is possible to provide an efficient cleaning method or apparatus for the fixing device without increasing the cost.

Further, since there is no need to use a cleaning roller or a cleaning pad dedicated to cleaning, there is no need to replace or maintain them, and the image forming apparatus can be downsized.

Further, since there is no need to purchase a dedicated cleaning sheet and the copy or print paper can be used as it is, the economic burden on the user can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing an example of an image forming apparatus to which the present invention is applied.

FIG. 2 is a sectional view of a main part for schematically explaining the first embodiment of the present invention.

FIG. 3 is a sectional view of a main part for schematically explaining a second embodiment of the present invention.

FIG. 4 is a sectional view of an essential part for schematically explaining a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 9 Downstream feed rotator pair (discharge roller pair) 11 Fixing heating rotator 12 Fixing pressure rotator 13 Upstream feed roller pair 14 Fixing rotator pair 15 Feed fixing device 16 Upstream recording sheet feed Feeding device 17 Recording sheet stopping means 18 Feeding guide 19 Recording sheet pressing means 21 Photoreceptor drum 22 Static eliminator 23 Cleaner 24 Charging device 25 Exposure device 26 Developing device 27 Transfer device 28 Fixing device 32 Feed cassette 33 Paper discharge tray S Recording Sheet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshihisa Fujimoto, 2-13-13 Azuchicho, Chuo-ku, Osaka City, Osaka Prefecture Inside Osaka International Building Minolta Co., Ltd. (72) Taizo Onishi, Azuchicho, Chuo-ku, Osaka City, Osaka No. 2-313 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H027 ED16 ED25 ED27 EE03 EE05 2H033 AA08 BA48 CA35 CA36 CA40 2H072 AB09 CA01 CB08 JA02 3F049 AA10 DA12 EA10 EA12 EA22 LA02 H07 LB03 9A001

Claims (6)

[Claims] 1. A cleaning method for a fixing device in an image forming apparatus, comprising: a recording sheet to be conveyed; and a pair of fixing rotators of the fixing device and an upstream recording sheet feeding device disposed upstream of the fixing device. In the state where both are held, the speed at which the upstream recording sheet feeding device conveys the recording sheet is slower than the speed at which the fixing rotator pair conveys the recording sheet, and The conveying force for conveying the recording sheet by the upstream recording sheet feeding device is set to be stronger than the conveying force for conveying the recording sheet by the fixing rotator pair. A cleaning method for the fixing device, wherein the fixing rotator pair is cleaned by causing slippage on the fixing member. 2. A method of cleaning a fixing device in an image forming apparatus, wherein a conveyed recording sheet includes a fixing rotator pair of the fixing device and a downstream feed rotator pair disposed downstream of the fixing device. In the state where the pair is held by both, the speed at which the downstream-side feed rotator pair conveys the recording sheet is faster than the speed at which the fixing rotator pair conveys the recording sheet; and The conveying force for conveying the recording sheet by the side feed rotator pair is set to be greater than the conveying force for conveying the recording sheet by the fixing rotator pair, and a slippage occurs between the fixing rotator pair and the recording sheet. A method for cleaning a fixing device, comprising cleaning the pair of fixing rotators by causing the fixing rotator pair. 3. A method for cleaning a fixing device in an image forming apparatus, wherein a conveyed recording sheet includes both a fixing rotator pair of the fixing device and a recording sheet stopping means disposed upstream of the fixing device. When the recording sheet is conveyed to a position straddling the recording sheet, the force by which the recording sheet stopping means stops the recording sheet is stronger than the conveying force by which the fixing rotating body pair conveys the recording sheet, and By stopping the recording sheet by operating the stopping means, the conveyance of the fixing rotator pair is continued, and the fixing rotator pair is cleaned by causing a slip between the fixing rotator pair and the recording sheet. A method for cleaning a fixing device. 4. The cleaning method for a fixing device according to claim 1, wherein a recording sheet having a maximum width that can be handled by the image forming apparatus is used when cleaning the fixing device. A method for cleaning a fixing device, comprising: 5. A cleaning device for a fixing device in an image forming apparatus, comprising: a fixing rotator pair provided in the fixing device for conveying a recording sheet while fixing the recording sheet; A recording sheet stopping means provided on the upstream side for stopping conveyance of the recording sheet, wherein the recording sheet to be conveyed is located at a position straddling both the fixing rotator pair and the recording sheet stopping means. When the recording sheet is conveyed, the recording sheet stopping means stops the conveyance of the recording sheet with a force stronger than the conveyance force for conveying the recording sheet by the fixing rotator pair, and the fixing rotator pair At this time, the conveyance of the recording sheet is continued, and the fixing rotator pair is cleaned by the slip generated between the fixing rotator pair and the recording sheet. A cleaning device of the fixing device, characterized in that the shall. 6. The fixing device cleaning device according to claim 5, wherein at the time of cleaning the fixing device, a recording sheet having a maximum width that can be handled by the image forming apparatus is used. Equipment cleaning device.