JP2000214717A - Image fixing device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a stable cleaning performable in accordance with circumstances even in the case of feeding a cleaning web with the same feeding amount by changing gaps formed at plural pressing positions different in the peripheral direction of a fixing rotating body in the case of pressing the cleaning web to the surface of the fixing rotating body by a pressing means. SOLUTION: The gaps formed at plural pressing positions different in the peripheral direction of the fixing rotating body in the case of pressing the cleaning web to the surface of the fixing rotating body by the pressing means are changed. In this device, the cleaning web 25 is constituted so as to be properly pressed to the surface of a fixing roller 20 by pressing rollers 26 to 28 pressing the web 25 to the surface of the roller 20 at plural spots different in the peripheral direction of the roller 20. The rollers 27 and 28 arranged on the downstream side in the rotating direction of the roller 20 from the roller 26 are constituted so as to abut on or separate from the surface of the roller 20 through the web 25 by sliding mechanisms 29 and 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image fixing apparatus for fixing an unfixed toner image formed on the surface of a transfer material by heating and pressing, and an image forming apparatus having the same.

[0002]

2. Description of the Related Art An example of a conventional electrophotographic image forming apparatus is shown in FIG.
This will be described using 10. In FIG. 10, the registration roller pair
The transfer material P conveyed between the photoconductor drum 102 and the transfer charger 103 by the transfer belt 101 after the toner image formed on the surface of the photoconductor drum 102 is transferred by the operation of the transfer charger 103 Is sent to the fixing device 105 to be heated and pressurized, and is discharged outside the apparatus.

The fixing device 105 includes a fixing roller 107 having a heater 106 therein, and a pressure roller 108 disposed opposite to the fixing roller 107.
The cleaning web 111 wound by the take-up roller 110 is provided so as to be movable in the direction opposite to the rotation direction of the fixing roller 107 while contacting the surface of the fixing roller 107, and the cleaning web 111 is provided with one pressing roller. The roller 112 is pressed against the surface of the fixing roller 107.

In the above construction, the transfer material P is fixed to a fixing roller.
When passing through the nip portion between the pressure roller 107 and the pressure roller 108, the surface of the fixing roller 107, which is in close contact with the unfixed toner image side, is contaminated by the toner, and this toner is removed from the surface of the fixing roller 107 by the cleaning web 111. It is supposed to be.

The cleaning web 111 is a delivery roller
The sheet is sent out of the fixing roller 107, is pressed against the surface of the fixing roller 107 by the pressing roller 112, and is wound by the winding roller 110. Conventionally, stable cleaning is generally performed by changing the feed amount of the cleaning web 111 in accordance with the length of the transfer material P to be used in the transport direction. Was determined based on the number of sheets used.

[0006]

However, in the above-mentioned conventional example, the cleaning web 111 is changed depending on the size of the transfer material P used to change the feed amount of the cleaning web 111 in accordance with the length of the transfer material P in the transport direction. There is a problem in that the number of used transfer materials P at the time of replacement differs, and the maintenance service interval cannot be set according to the counter of the number of used transfer materials.

Further, when the cleaning web 111 is fed at the same feed amount irrespective of the length of the transfer material P in the transport direction, if the length of the transfer material P in the transport direction is large, sufficient cleaning ability is not exhibited, and There is a possibility that the image formed on the transfer material P is stained by the toner that has slipped through the web 111 and the image quality is reduced.

[0008] The present invention is to solve the above problems,
The purpose is to feed the cleaning web with the same feed amount by changing the intervals between a plurality of different pressing positions in the circumferential direction of the fixing rotator on the surface of the fixing rotator of the cleaning web by the pressing means. Therefore, an image fixing apparatus and an image forming apparatus having the same capable of performing stable cleaning according to the situation and performing maintenance service such as cleaning web replacement according to the counter of the number of sheets used are provided. Things.

[0009]

A typical configuration according to the present invention for achieving the above object is an image fixing apparatus for fixing an unfixed toner image formed on the surface of a transfer material by heating and pressure. A fixing rotator to which the surface of the transfer material on which the unfixed toner image is formed is in close contact, a cleaning web that contacts the surface of the fixing rotator to clean the surface of the fixing rotator, and Web transport means for transporting while contacting the surface of the fixing rotator;
Pressing means for pressing the cleaning web against the surface of the fixing rotator at a plurality of different locations in the circumferential direction of the fixing rotator, and pressing the cleaning web on the surface of the fixing rotator of the cleaning web by the pressing means. An image fixing apparatus characterized in that intervals between a plurality of different pressing positions in a circumferential direction of a fixing rotating body are changed.

Since the present invention is constructed as described above, the distance between a plurality of different pressing positions in the circumferential direction of the fixing rotator on the surface of the fixing rotator of the cleaning web by the pressing means is changed. Even if the cleaning web is fed by the feeding amount, stable cleaning can be performed according to the situation, and maintenance services such as replacement of the cleaning web can be performed according to the counter of the number of sheets used.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of an image fixing apparatus according to the present invention and an image forming apparatus provided with the same, which is applied to an electrophotographic copying machine. FIG. 1 is a schematic cross-sectional explanatory view showing the configuration of a first embodiment of an image forming apparatus provided with an image fixing device according to the present invention.
3 is an enlarged view of a part around the fixing rotator according to the first embodiment.

In FIG. 1, a transfer material P made of paper, synthetic resin, or the like separated and fed one by one by a feeding means (not shown) is corrected for skew by a pair of registration rollers 1, and becomes an image forming means. The photosensitive drum 2 is conveyed between the photosensitive drum 2 and a transfer charger 3 arranged opposite to the photosensitive drum 2 in synchronization with the rotation of the electrophotographic photosensitive drum 2.

On the other hand, after the photoconductive layer provided on the surface of the photosensitive drum 2 is uniformly charged by the primary charger 4, the photosensitive drum 2 is exposed to a light image 5 of the original, and is statically placed on the surface of the photosensitive drum 2. An electrostatic latent image is formed.

The original placed on the original table glass 6 is irradiated by the halogen lamp 7 and the reflector 8, and the light image of the reflected original enters the zoom lens 12 via the reflection mirrors 9, 10, 11. Then, the surface of the uniformly charged photosensitive drum 2 is irradiated via the reflection mirrors 13, 14, 15 to form an electrostatic latent image. At this time, the image is reduced, enlarged, or made into the same size depending on the positional relationship between the reflection mirror 11 and the zoom lens 12.

The electrostatic latent image formed on the surface of the photosensitive drum 2 reaches the position of the developing unit 16 with the rotation of the photosensitive drum 2 and is developed by the toner supplied from the developing unit 16 to form a toner image. Visualized.

The toner image formed on the surface of the photosensitive drum 2 is transferred to the transfer charger 3 as the photosensitive drum 2 rotates.
Goes to the transfer section where. Then, the transfer material P conveyed by the registration roller pair 1 in synchronization with the rotation of the photoconductor drum 2 is guided to a transfer section between the photoconductor drum 2 and the transfer charger 3, where the photoconductor drum is transferred. 2 is adhered to the surface.

At this position, a charge having a polarity opposite to that of the toner image is applied to the back surface of the transfer material P by the transfer charger 3, and the toner image on the photosensitive drum 2 is transferred and attracted onto the transfer material P by electrostatic force. Is transcribed.

A separation charger 17 is disposed downstream of the transfer charger 3 in the conveying direction of the transfer material P, and the charge of the transfer material P on which the toner image has been transferred is lost by corona discharge by the separation charger 17. Then, the transfer material P loses its attraction to the photosensitive drum 2 and is separated from the photosensitive drum 2 by the elasticity and the weight of the transfer material P itself.

The transfer material P separated from the photoreceptor drum 2 is sent to an image fixing device 19 by a conveyor belt 18, and the transfer material P
A fixing roller 20 serving as a fixing rotator having a surface on the side where the unfixed toner image formed on the surface is formed, and a pressing roller serving as a pressing rotator disposed opposite to the fixing roller 20 After being heated and pressurized when passing through the nip portion 21, it is discharged outside the machine.

At this time, the moving speed of the outer peripheral surface of the fixing roller 20 for transferring the transfer material P and the moving speed of the outer peripheral surface of the photosensitive drum 2 are generally set to be different from each other. The moving speed of the outer peripheral surface of the fixing roller 20 is set to be slightly lower than the moving speed of the fixing roller 20.

The transfer of the toner image to the rear end portion of the transfer material P which is still in the transfer portion due to a shock when the leading end of the transfer material P enters the nip portion between the fixing roller 20 and the pressure roller 21. This is to prevent the occurrence of deviation.

As described above, the image fixing device 19 includes a fixing roller 20 provided with a halogen heater 22 therein,
A feed roller 23 and a take-up roller 24 which have a pressure roller 21
The cleaning web 25 wound by the fixing roller 20
The fixing roller 20 is provided so as to be movable in a direction opposite to the rotation direction thereof while being in contact with the surface of the fixing roller 20.

The cleaning web 25 contacts the surface of the fixing roller 20 and removes toner and other substances adhered to the surface of the fixing roller 20 for cleaning. The used cleaning web 25 is sequentially sent out from the roller 23 and is taken up by the take-up roller 24.

In the case of this embodiment, the cleaning web 25
Is moved by a predetermined amount by pulling a solenoid, which is a driving means (not shown), so that the take-up roller 24 is rotated by a predetermined amount, and is fixed for a fixing operation of one transfer material P regardless of the size, material or thickness of the transfer material P , And the amount by which the cleaning web 25 is fed by one solenoid pulling is set at 0.05 to 0.06 mm.

The cleaning web 25 is appropriately pressed against the surface of the fixing roller 20 by pressing rollers 26, 27 and 28 serving as pressing means for pressing against the surface of the fixing roller 20 at a plurality of different positions in the circumferential direction of the fixing roller 20. It is supposed to be.

A pressing roller 26 disposed on the most upstream side in the rotation direction (clockwise direction in the drawing) of the fixing roller 20 is constantly pressed against the surface of the fixing roller 20 via the cleaning web 25, and The cleaning web 25 is rotatably provided while pressing the cleaning web 25 against the surface of the fixing roller 20 with the movement of the cleaning web 25.

Further, the fixing roller is more than the pressing roller 26.
The pressing rollers 27, 28 disposed downstream of the rotation direction 20 (clockwise direction in the drawing) abut or separate from the surface of the fixing roller 20 via the cleaning web 25 by slide mechanisms 29, 30, respectively. When the pressing rollers 27 and 28 are pressed against the surface of the fixing roller 20 via the cleaning web 25, the cleaning web 25 is fixed with the movement of the cleaning web 25. The roller 20 is rotatably provided while being pressed against the surface of the roller 20.

In this embodiment, the size of the transfer material P to be used is detected by size detection means provided in a cassette (not shown) that accommodates the transfer material P, and the length of the transfer material P in the transport direction is less than 220 mm. If so, as shown in FIG. 2, the pressing roller 27 moves downward in FIG. 2 along the slide mechanism 29 and is pressed against the surface of the fixing roller 20 via the cleaning web 25, and the pressing roller 28 slides. Mechanism 30
Moving upward along FIG.
Is separated from the surface of the fixing roller 20.

As a result, the cleaning web 25 is fixed to the fixing roller 20 in the area of the separation W1 between the pressing rollers 26 and 27.
The cleaning web 25 is pressed against the surface of the transfer material P by pulling the solenoid once for one fixing operation of the transfer material P.
Is sent 0.05 to 0.06 mm.

The length of the transfer material P in the transport direction is 220
3, the pressing roller 28 moves downward in FIG. 3 along the slide mechanism 30 and is pressed against the surface of the fixing roller 20 via the cleaning web 25 as shown in FIG. 27 moves upward along the slide mechanism 29 in FIG.

As a result, the cleaning web 25 is pressed against the surface of the fixing roller 20 in the area of the separation distance W2 (W2> W1) between the pressing rollers 26 and 28, and once per fixing operation of one transfer material P. , The cleaning web 25 is also fed by 0.05 to 0.06 mm.

In the above construction, the transfer material P is fixed to the fixing roller.
When passing through the nip portion between the pressure roller 20 and the pressure roller 21, the surface of the fixing roller 20 which is in close contact with the unfixed toner image side is contaminated with toner, but this toner is removed from the surface of the fixing roller 20 by the cleaning web 25. Is done.

Under these circumstances, transfer materials P of various sizes
As a result of performing the fixing operation and performing the cleaning operation using the cleaning web 25, the cleaning ability was sufficiently exhibited for the transfer material P of any size.

According to the above arrangement, the distance between a plurality of different pressing positions in the circumferential direction of the fixing roller 20 on the surface of the fixing roller 20 of the cleaning web 25 by the pressing rollers 26, 27, 28 serving as pressing means. The cleaning can be performed stably according to the situation even if the cleaning web 25 is fed with the same feed amount by changing the cleaning web, and maintenance service such as replacement of the cleaning web 25 can be performed according to the counter of the number of sheets used. It is.

Next, a second embodiment of the image fixing apparatus according to the present invention and an image forming apparatus having the same will be described with reference to FIGS. FIG. 4 is a schematic cross-sectional explanatory view showing a configuration of an image forming apparatus provided with an image fixing device according to a second embodiment of the present invention, and FIGS. 5 and 6 are partially enlarged views around a fixing rotator in the second embodiment. is there. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, the pressing roller 26 is disposed at the most upstream side in the rotation direction (clockwise direction in the drawing) of the fixing roller 20 and the rotation direction of the fixing roller 20 (see FIG. A pressing roller 27 disposed on the downstream side (clockwise direction) is constantly pressed against the surface of the fixing roller 20 via the cleaning web 25, and the cleaning web 25 is moved with the fixing roller 20 as the cleaning web 25 moves. It is provided to be rotatable while being pressed against the surface.

Then, a pressing roller 28 disposed further downstream than the pressing roller 27 in the rotation direction (clockwise direction in the drawing) of the fixing roller 20 cleans the surface of the fixing roller 20 by the slide mechanism 30. It is configured to be able to contact or separate via the web 25.

In this embodiment, when the transfer material P to be used is plain paper, the pressing roller 28 moves upward along the slide mechanism 30 in FIG. The cleaning web 25 is separated from the surface of the fixing roller 20.

As a result, the cleaning web 25 is fixed to the fixing roller 20 in the area of the separation W3 between the pressing rollers 26 and 27.
The cleaning web 25 is pressed against the surface of the transfer material P by pulling the solenoid once for one fixing operation of the transfer material P.
Is sent 0.05 to 0.06 mm.

When the transfer material P to be used is thick paper or an OHP sheet, the pressing roller 28 is moved along the slide mechanism 30 as shown in FIG. The cleaning web 25 moves downward and is pressed against the surface of the fixing roller 20 via the cleaning web 25. The cleaning web 25 is pressed against the surface of the fixing roller 20 by pressing rollers 26, 27 and 28, respectively.

At this time, the cleaning web 25 is pressed against the surface of the fixing roller 20 in the area of the separation distance W4 (W4> W3) between the pressing rollers 26 and 28, and once per fixing operation of one sheet of the transfer material P. , The cleaning web 25 is also fed by 0.05 to 0.06 mm.

In such a situation, the fixing operation is performed for the transfer materials P of various materials and thicknesses, and the cleaning operation is performed by the cleaning web 25. As a result, the cleaning ability is sufficiently exhibited for any type of the transfer materials P. Was done.
Other configurations are the same as those of the first embodiment, and the same effects can be obtained.

Next, a third embodiment of the image fixing apparatus according to the present invention and an image forming apparatus having the same will be described with reference to FIGS. FIG. 7 is a schematic cross-sectional explanatory view showing a configuration of an image forming apparatus including an image fixing device according to a third embodiment of the present invention, and FIGS. 8 and 9 are partially enlarged views around a fixing rotating body in the third embodiment. is there. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, the pressing roller 26 disposed on the most upstream side in the rotation direction (clockwise direction in the drawing) of the fixing roller 20 and the rotational direction of the fixing roller 20 (clockwise in FIG. The pressing roller 27 disposed on the downstream side in the (circumferential direction) is constantly pressed against the surface of the fixing roller 20 via the cleaning web 25, and the cleaning web 25 is moved to the fixing roller 20 with the movement of the cleaning web 25. It is provided rotatably while pressing against the surface.

Further, the pressing roller 27 is constantly pressed against the surface of the fixing roller 20 via the cleaning web 25, and the surface of the fixing roller 20 is moved by a slide mechanism 31 arranged in the circumferential direction of the fixing roller 20. The fixing roller 20 is configured to be movable along the circumferential direction of the fixing roller 20 while being in contact with the fixing roller 20 via the cleaning web 25.

Further, the developing unit 16 is provided with a toner remaining amount detecting means (not shown), and the toner is supplied by the toner remaining amount detecting means. The toner consumption during toner image formation is estimated from the toner supply interval at this time. If the toner consumption is less than 0.1 g per A4 size, the pressing roller 27 moves along the slide mechanism 31 as shown in FIG. The cleaning web 25 is moved to the left side (upstream in the rotation direction of the fixing roller 20) of FIG. 8 and the cleaning web 25 is pressed against the surface of the fixing roller 20 in the area of the separation W5 between the pressing rollers 26 and 27, and the transfer material P The cleaning web 25 is fed by 0.05 to 0.06 mm by pulling the solenoid once per sheet fixing operation.

If the toner consumption is 0.1 g or more per A4 size, a pressing roller is used as shown in FIG.
27 along the slide mechanism 31 in the right side of FIG.
And the cleaning web 25 is pressed against the surface of the fixing roller 20 in the area of the separation distance W6 (W6> W5) between the pressing rollers 26 and 27, thereby fixing one sheet of the transfer material P. The cleaning web 25 is fed by 0.05 to 0.06 mm by one solenoid pull per operation.

In such a situation, a fixing operation is performed on the transfer material P on which an image has been formed with various amounts of toner consumption, and a cleaning operation by the cleaning web 25 is performed. As a result, all the transfer materials P have sufficient cleaning ability. Was demonstrated. Other configurations are the same as those of the first embodiment, and the same effects can be obtained.

[0049]

Since the present invention has the above-described configuration and operation, the distance between a plurality of pressing positions different in the circumferential direction of the fixing rotator on the surface of the fixing rotator of the cleaning web by the pressing means is provided. By changing the value, the cleaning can be stably performed according to the situation even if the cleaning web is fed with the same feeding amount, and the maintenance service such as replacement of the cleaning web can be performed according to the counter of the number of sheets used.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional explanatory view showing a configuration of a first embodiment of an image forming apparatus including an image fixing device according to the present invention.

FIG. 2 is a partially enlarged view around a fixing rotating body according to the first embodiment.

FIG. 3 is a partially enlarged view around a fixing rotating body according to the first embodiment.

FIG. 4 is a schematic cross-sectional explanatory view showing a configuration of a second embodiment of an image forming apparatus including an image fixing device according to the present invention.

FIG. 5 is a partially enlarged view around a fixing rotating body according to a second embodiment.

FIG. 6 is a partially enlarged view around a fixing rotating body according to a second embodiment.

FIG. 7 is a schematic sectional view illustrating a configuration of an image forming apparatus including an image fixing device according to a third embodiment of the invention.

FIG. 8 is a partially enlarged view around a fixing rotating body according to a third embodiment.

FIG. 9 is a partially enlarged view around a fixing rotating body according to a third embodiment.

FIG. 10 is a diagram illustrating a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Registration roller pair, 2 ... Photoreceptor drum, 3 ... Transfer charger, 4 ... Primary charger, 5 ... Exposure, 6 ... Platen glass
7 Halogen lamp, 8 Reflector, 9, 10, 11 Reflector mirror, 12 Zoom lens, 13, 14, 15 Reflector mirror, 16
... Developer, 17 ... Separation charger, 18 ... Conveyer belt, 19 ... Image fixing device, 20 ... Fixing roller, 21 ... Pressurizing roller, 22 ... Halogen heater, 23 ... Sending roller, 24 ... Winding roller,
25: cleaning web, 26, 27, 28: pressing roller, 29, 30, 31: slide mechanism, P: transfer material

Claims (5)

[Claims] An image fixing apparatus for heating and pressure fixing an unfixed toner image formed on a surface of a transfer material, comprising: a fixing rotator having a surface on the side of the transfer material on which the unfixed toner image is formed; A cleaning web that contacts the surface of the fixing rotator to clean the surface of the fixing rotator; a web conveying unit that conveys the cleaning web while contacting the surface of the fixing rotator; and Pressing means for pressing the surface of the fixing rotator at a plurality of different locations in the circumferential direction of the fixing rotator; and An image fixing device, characterized in that intervals between a plurality of different pressing positions in a circumferential direction are changed. 2. The interval between a plurality of different pressing positions of the cleaning web on the surface of the fixing rotator by the pressing unit in the circumferential direction of the fixing rotator depends on the size, material, and thickness of the transfer material. The image fixing device according to claim 1, wherein the image is changed by: 3. The interval between a plurality of different pressing positions of the cleaning web on the surface of the fixing rotator in the circumferential direction of the fixing rotator by the pressing unit is set such that the longer the length of the transfer material in the conveying direction, the longer the distance. 3. The image fixing device according to claim 2, wherein the image fixing device is configured to be large. 4. The interval between a plurality of different pressing positions of the cleaning web on the surface of the fixing rotator in the circumferential direction of the fixing rotator by the pressing unit is set such that the larger the amount of consumed toner at the time of forming a toner image, the larger the amount of toner consumption. The image fixing device according to claim 1, wherein the image fixing device is configured to be large. 5. An image forming apparatus comprising: the image fixing apparatus according to claim 1; and an image forming unit that forms an unfixed toner image on a transfer material.