JP2021021809A - Fixing device, and image forming apparatus - Google Patents

Abstract

To achieve, with one driving source, a driving source of a polishing roller that polishes a fixing belt and a driving source that brings the polishing roller into pressure contact with the fixing belt or separates the polishing roller from the fixing belt.SOLUTION: A fixing device comprises: a fixing belt that is rotated while being stretched over a plurality of support members; a pressure member that forms a fixing nip part between the fixing belt and pressure member; and a belt polishing mechanism that polishes a surface of the fixing belt. The belt polishing mechanism includes: a polishing roller that is provided to be contactable/separable with respect to the fixing belt, and rubs the surface of the fixing belt while being in pressure contact with the fixing belt; an opposing member that is opposite to the polishing roller with the fixing belt therebetween, and forms a polishing nip part between the fixing belt and opposing member; and polishing roller rotation driving means that rotates the polishing roller. The polishing roller rotation driving means includes a first rotation driving member that is disposed coaxially with the polishing roller, and a second rotation driving member that transmits a driving force to the first rotation driving member. The polishing rotation driving means also serves as a contact/separation driving unit that brings the polishing roller into pressure contact with the fixing belt or separates the polishing roller from the fixing belt.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fixing device and an image forming device.

In an image forming apparatus such as a copying machine or a printer, when a large amount of paper is passed through the fixing device, the edge portion of the paper comes into contact with the fixing belt, so that the fixing belt is scratched and an abnormal image is generated in the printing portion. In order to suppress the occurrence of such an abnormal image, there is a technique of polishing and removing scratches generated on the fixing belt with a polishing roller (for example, Patent Document 1).

In Patent Document 1, the polishing roller is pressed against the fixing belt by a spring and a cam during polishing (during maintenance), and has a drive source for separating the polishing roller except during maintenance such as passing paper. ing. Further, in order to polish the fixing belt in a short time, a speed difference is provided between the fixing belt and the polishing roller, and the drive source of the polishing roller is made independent. A fixing device having such a fixing belt polishing function requires at least two drive sources, and has a problem that the size of the device is increased and the cost is increased.

One aspect of the present invention is to realize a drive source of a polishing roller for polishing a fixing belt and a drive source for pressing and separating the polishing roller from the fixing belt with one drive source, and it is possible to reduce the size and cost of the apparatus. An object of the present invention is to provide a fixing device.

The fixing device according to the present invention polishes the surface of a fixing belt that is stretched and rotated by a plurality of support members, a pressure member that forms a fixing nip portion between the fixing belts, and the surface of the fixing belt. A polishing roller including a belt polishing mechanism, which is provided so as to be detachable from the fixing belt and which rubs the surface of the fixing belt in a state of being in pressure contact with the fixing belt, and the polishing. The polishing roller rotation driving means is provided with an opposing member which faces the roller via the fixing belt and forms a polishing nip portion between the fixing belt and a polishing roller rotation driving means for rotating the polishing roller. The polishing roller includes a first rotation driving member disposed coaxially with the polishing roller and a second rotation driving member for transmitting a driving force to the first rotation driving member. The means is configured as a fixing device, which also serves as a contact / detachment drive unit for pressing and separating the polishing roller from the fixing belt.

According to the present invention, the drive source of the polishing roller for polishing the fixing belt and the drive source for pressing and separating the polishing roller from the fixing belt can be realized by one drive source, and the device can be downsized and the cost can be suppressed. ..

It is a block diagram of the state in which the polishing roller and the fixing belt are pressure-contacted in the conventional ordinary belt polishing structure in a fixing device. Of the conventional belt polishing configurations shown in FIG. 1, it is a schematic configuration diagram in a state where the polishing roller and the fixing belt are separated from each other. It is the configuration schematic of the state in which the polishing roller and the fixing belt are pressure-contacted in the belt polishing structure of this Example in a fixing device. Of the belt polishing configurations of the present embodiment shown in FIG. 3, it is a schematic configuration diagram in a state where the polishing roller and the fixing belt are separated from each other. It is an enlarged schematic view of the polishing structure shown in FIG. It is an enlarged schematic view of the polishing structure shown in FIG. It is a figure which shows an example of the image forming apparatus provided with the fixing apparatus in this Example.

Hereinafter, embodiments of the fixing device and the image forming device will be described in detail with reference to the accompanying drawings.
The fixing device according to this embodiment is provided with a polishing roller for polishing the fixing belt in view of the fact that the belt surface texture such as scratches on the fixing belt and the surface roughness of the belt affects the quality of the image on the recording medium. The drive source of the polishing roller and the drive source for pressing and separating the polishing roller from the fixing belt are realized by one drive source instead of a plurality of drive sources. With such a configuration, the device can be miniaturized and the cost can be suppressed. Such features will be described in detail with reference to the following drawings.

As a general configuration, as shown in FIGS. 1 and 2, in the fixing device, a fixing roller 29 and a pressure member 27 (for example, a pressure roller) are used to drive the fixing belt 26 and fix the toner on the recording medium. Be placed.

On the other hand, as a device for polishing and removing scratches on the fixing belt 26, a polishing unit 50, which is a belt polishing mechanism for polishing the surface of the fixing belt 26, is arranged in the vicinity of an opposing member 29 (for example, a fixing roller). The facing member 29 is composed of at least one support member among a plurality of support members such as the fixing roller 29 and the heating roller 30. As a result, a member that supports the fixing belt 26 can be used as the opposing member of the polishing roller 51, and the component cost can be reduced.

The polishing unit 50 includes a polishing roller 51 for polishing the fixing belt 26, a spring 53 for pressing the polishing roller 51 against the fixing belt 26, and a holding holder 52 for holding the polishing roller 51. On the same axis of the polishing roller 51, in order to rotate the polishing roller 51, a polishing roller drive gear 34 as a polishing roller rotation driving means is arranged on one side of the polishing roller 51 which does not overlap with the fixing belt 26. The facing member 29 faces the polishing roller 51 via the fixing belt 26, and forms a polishing nip portion between the polishing roller 51 and the fixing belt 26. For example, the opposing member 29 is composed of a fixing roller that forms a fixing nip as a polishing nip portion between the fixing belt 26 and the pressing member 27 with the fixing belt 26 sandwiched between them. As a result, the fixing roller can be used as one of the members supporting the fixing belt 26 that can be used as the opposing member of the polishing roller 51.

Further, the facing member 29 may be configured as a fixing member different from the plurality of support members. By using a fixing member other than the member that supports the fixing belt 26 as the opposing member of the polishing roller 51, it is not necessary to have the supporting function of the fixing belt 26, and the polishing quality can be further improved with respect to the material and the like. You can choose.

A drive transmission gear 35 is provided on the circumference of the polishing roller drive gear 34 in order to transmit the drive from a drive source (for example, a motor) (not shown) to the polishing roller drive gear 34. The drive transmission gear 35 is arranged at a position that does not overlap with the projection surface of the opposing member 29 in order to avoid interference with the opposing member 29. A drive transmission gear 35 is rotated by a drive source (not shown) to rotate the polishing roller 51.

Further, in the conventional configuration shown in FIG. 1, for example, a polishing roller pressure contact / separation mechanism 54 is provided as a mechanism for moving the polishing roller 51 in the direction of the polishing roller moving (pressing) direction 33 and pressing / separating the polishing roller 51 from the fixing belt 26. ing. The polishing roller pressure contact / separation mechanism 54 has a cam 56 for moving the polishing unit 50 and a spring 55 for pressing the polishing unit 50 with the cam 56. By rotating the cam 56 with a drive source at the time of non-figure, the polishing roller 51 is pressed against the fixing belt 26 (FIG. 1) and separated (FIG. 2). That is, the polishing roller 51 is provided so as to be detachable from the fixing belt 26, and rubs the surface of the fixing belt 26 in a state of being in pressure contact with the fixing belt 26.

In this embodiment, as shown in FIGS. 3 and 4, the polishing roller 51 and the polishing roller drive gear 34 are configured to be rotatable around the drive transmission gear 35 having a fixed central axis. As a result, the polishing roller 51 itself can be moved by the driving force for rotating the polishing roller 51. That is, the polishing roller drive gear 34, which is the first rotation drive member arranged coaxially with the polishing roller 51, and the drive transmission gear, which is the second rotation drive member that transmits the driving force to the polishing roller drive gear 34. The 35 has a function as a polishing roller rotation drive means and a function as a contact / detachment drive unit for pressing and separating the polishing roller 51 from the fixing belt 26. Further, in order to heat the fixing belt 26, a heating roller 30 in which a heating heater 31 is inserted is provided. Further, in order to apply tension to the fixing belt 26, the heating roller 30 is urged in the direction 32 by an elastic member such as a spring. The fixing roller 29 and the heating roller 30 are support members that support the fixing belt 26.

For example, when the drive transmission gear 35 is rotated in the D1 direction of FIG. 5 by a drive source (not shown), a gear meshing force is generated in the polishing roller drive gear 34 in the direction 36-a. Since this force is in the direction of pressing the polishing roller 51 against the fixing belt 26, for example, via a power conversion mechanism such as a link mechanism connecting the axes of the polishing roller drive gear 34 and the drive transmission gear 35, as shown in FIG. The polishing roller 51 moves downward in the polishing roller moving (pressing) direction 33, and the polishing roller 51 is pressed against the fixing belt 26. As described above, since the central axis of the polishing roller drive gear 34 is not fixed, the polishing roller 51 moves until it comes into contact with the fixing belt 26 by the meshing force generated in the direction 36-a. As for the timing of pressure contact, in the above-mentioned polishing roller rotation driving means, the polishing roller 51 is in the forward direction (for example, the direction opposite to the rotation direction of the fixing belt 26. The surface of the polishing roller is the surface of the fixing belt facing the surface of the polishing roller. The polishing roller 51 is pressed against the fixing belt 26 when it is rotated in the same direction as the moving direction. As a result, the polishing roller 51 can be rotated in this direction to bring the polishing roller 51 into contact with the fixing belt 26.

On the other hand, when the drive transmission gear 35 is rotated in the D2 direction of FIG. 6 by a drive source (not shown), a gear meshing force is generated in the polishing roller drive gear 34 in the direction 36-b. Since this force is in the direction of separating the polishing roller 51 from the fixing belt 26, for example, through a power conversion mechanism such as a link mechanism connecting the axes of the polishing roller drive gear 34 and the drive transmission gear 35, as shown in FIG. The polishing roller 51 moves upward in the polishing roller moving (pressing) direction 33, and is separated from the fixing belt 26. As described above, since the central axis of the polishing roller drive gear 34 is not fixed, the polishing roller 51 causes the elastic force of the spring 53 to be balanced by the meshing force generated in the direction 36-b. It works. As for the timing of separation, in the above-mentioned polishing roller rotation driving means, the polishing roller 51 moves in the opposite direction (for example, the same direction as the rotation direction of the fixing belt 26. The surface of the polishing roller faces the surface of the polishing roller. The polishing roller 51 is separated from the fixing belt 26 when it is rotated in the direction opposite to the direction. As a result, the polishing roller 51 can be rotated in this direction to separate the polishing roller 51 from the fixing belt 26.

The polishing unit 50, which is a belt polishing mechanism, controls so that the polishing roller 51 is in pressure contact with the fixing belt 26 or the polishing roller 51 is separated from the fixing belt 26 when the polishing roller rotation driving means is stopped. May be good. Further, by bringing the polishing roller 51 into contact with the fixing belt 26, the polishing roller 51 is brought to the fixing belt 26 (at the same speed) in a polishing state, or the rotation of the polishing roller 51 is stopped and only the fixing belt 26 moves. It is possible to create each polishing state.
Further, the polishing roller 51 may be rotationally driven at a speed different from the surface speed when the fixing belt 26 is rotationally driven. As a result, the polishing quality of the fixing belt 26 can be improved and the polishing time can be shortened.

Further, in a state where the polishing roller 51 is in pressure contact with the fixing belt 26, the polishing roller 51 faces the opposing member 29 via the fixing belt 26 to form a polishing nip portion between the polishing roller 51 and the fixing belt 26, and the fixing belt 26 is formed. However, the rotation locus is changed along the shape of at least a part of the peripheral surface of the polishing roller 51. For example, the polishing roller 51 is moved in the width direction perpendicular to the rotation direction of the fixing belt 26 via a power conversion mechanism such as a link mechanism, while changing the contact portion between the fixing belt 26 and the polishing roller 51. Grind. As a result, the contact area between the polishing roller 51 and the fixing belt 26 is increased, and the polishing time can be shortened as compared with the case of polishing at the same portion.

Usually, the fixing device includes a fixing roller for fixing the toner and a pressure roller arranged opposite to the fixing roller and forming a fixing nip portion between the fixing roller and the fixing belt. In particular, commercial printers often use a fixing belt in order to secure heat storage and followability to the surface shape of the paper due to its high speed and handling of uneven paper. On the other hand, commercial printers are required to have high quality images and durability. This is not a problem at the initial stage of using the machine, but when a large amount of paper is passed, the edge portion of the paper comes into contact with the fixing belt, so that the fixing belt is scratched and an abnormal image is generated in the printed portion. In such a case, the above problem can be solved by replacing the belt with a new fixing belt, but it is necessary to reduce the replacement cost and the downtime of the machine required for the replacement.

Therefore, for example, as in Patent Document 1, for the purpose of shortening the polishing time, the fixing belt is wound around the polishing roller to secure the area to be polished and to make the contact area uniform, and the fixing belt is formed by the polishing roller. Techniques have been considered for polishing and removing the above scratches, suppressing the occurrence of abnormal images, and extending the life of parts. However, having a polishing function requires a plurality of drive sources, which causes a new problem that the device becomes large and the cost increases. In this embodiment, as described above, the drive source of the polishing roller for polishing the fixing belt and the drive source for pressing and separating the polishing roller from the fixing belt are not a plurality of drive sources. By realizing it with one drive source, the device can be downsized and the cost can be suppressed.

The control in this embodiment is controlled by, for example, the control unit 800 (or the control unit of the fixing device) of the image forming apparatus provided with the fixing device. The control unit 800 can use general hardware composed of an arithmetic unit having a processor such as a CPU, and the above control is performed by the arithmetic unit executing a program. The main body of the processing performed by executing the program may be an arithmetic unit, and includes a dedicated circuit (for example, FPGA (Field-Programmable Gate Array) or ASIC (Application Specific Integrated Circuit)) for performing specific processing. May be good.

The fixing device in this embodiment is mounted on, for example, the image forming device shown in FIG. 7. In the figure, reference numeral 100 indicates a tandem type intermediate transfer type image forming apparatus main body as an image forming apparatus, and 200 indicates a paper feed table on which the image forming apparatus main body 100 is placed. Further, a tandem type intermediate transfer type image forming unit (hereinafter, referred to as a tandem type image forming unit) 20 in which a plurality of image forming means 1Y, 1M, 1C, and 1K are arranged side by side inside the image forming apparatus main body 100. Is provided, and the subscripts Y, M, C, and K attached to the above reference numerals indicate the respective colors of yellow, magenta, cyan, and black, respectively. The image forming apparatus main body 100 is provided with an endless belt-shaped intermediate transfer body (hereinafter, referred to as an intermediate transfer belt) 10 near the center. The intermediate transfer belt 10 is hung around a plurality of support rollers 14, 15, 15', 16 and the like so that it can be rotationally conveyed clockwise in the drawing.
In this illustrated example, a cleaning device 17 for an intermediate transfer belt is provided on the left side of the support roller (secondary transfer opposed roller) 16. The cleaning device 17 removes residual toner remaining on the intermediate transfer belt 10 after image transfer.

On the intermediate transfer belt 10 stretched between the support rollers 14 and the support rollers 15, four images of yellow (Y), magenta (M), cyan (C), and black (K) are displayed along the transport direction. The forming means 1Y, 1M, 1C, and 1K (hereinafter referred to as 1Y, M, C, and K) are arranged side by side to form the tandem image forming unit 20. Each image forming means 1Y, M, C, K of the tandem type image forming unit 20 is a photoconductor drum 2Y, M, C, as an image carrier for supporting toner images of each color of yellow, cyan, magenta, and black. Has K.
As shown in FIG. 7, two exposure devices 4 are provided on the tandem image forming unit 20. Each exposure device 4 corresponds to two image forming means (1Y and 1M, 1C and 1K), for example, two light source devices (semiconductor laser, semiconductor laser array, multi-beam light source, etc.) and a coupling optical system. , A common optical deflector (polygon mirror, etc.), an optical scanning exposure device consisting of two scanning imaging optical systems, etc., depending on the image information of each color of yellow, cyan, magenta, and black. The photoconductor drums 2Y, M, C, and K are exposed to form an electrostatic latent image.

Further, around the photoconductor drums 2Y, M, C, and K of the image forming means 1Y, M, C, and K, charging devices 3Y, M, which uniformly charge each photoconductor drum prior to the above exposure. C, K, a developing device 5Y, M, C, K that develops an electrostatic latent image formed by the above-mentioned exposure device 4 with toner of each color, and a cleaning device for a photoconductor that removes transfer residual toner on a photoconductor drum. 7Y, M, C, and K are provided. Further, at the primary transfer position where the toner image is transferred from the photoconductor drums 2Y, M, C, K to the intermediate transfer belt 10, each photoconductor drum 2Y, M, C, K with the intermediate transfer belt 10 sandwiched between them. Primary transfer rollers 62Y, M, C, and K are provided as components of the primary transfer means so as to face each other.

Of the plurality of support rollers that support the intermediate transfer belt 10, the support roller 14 is a drive roller that rotationally drives the intermediate transfer belt 10 and is connected to a motor via a drive transmission mechanism (gear, pulley, belt, etc.) (not shown). Has been done. When a black monochromatic image is formed on the intermediate transfer belt 10, the support rollers 15 and 15'other than the drive roller 14 are moved by a moving mechanism (not shown) to move the yellow, cyan, and magenta photoconductor drums. It is possible to separate 2Y, M, and C from the intermediate transfer belt 10. In addition, the backup roller 63 is also provided as a roller for supporting the intermediate transfer belt 10.
A secondary transfer device 22 is provided on the side of the intermediate transfer belt 10 opposite to the tandem image forming unit 20. In the illustrated example, the secondary transfer device 22 uses the image on the intermediate transfer belt 10 as a transfer medium by pressing the secondary transfer roller 16'on the secondary transfer opposed roller 16 and applying a transfer electric field. Transfer to a recording medium P (recording material).

Further, next to the secondary transfer device 22, a fixing device 25 for fixing the transferred image on the recording medium P is provided. The recording medium P on which the image is transferred by the secondary transfer device 22 is transferred to the fixing device 25 by the transfer belt 24 supported by the two rollers 23. Of course, the portion of the transport belt 24 may be a fixed guide member, or may be a transport roller, a transport roller, or the like.
In the illustrated example, a recording medium P is provided below the secondary transfer device 22 and the fixing device 25 so as to record an image on both sides of the recording medium P in parallel with the tandem image forming unit 20 described above. A sheet reversing mechanism 28 for reversing and transporting is provided.

Further, the recording medium P is conveyed as follows. First, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the recording medium P is fed out from one of the paper feed trays 44 provided in multiple stages in the paper bank 43. The unwound recording medium P is separated one by one by the separation roller 45, introduced into the paper feed path 46, conveyed by the transfer roller pair 47, and guided to the paper feed path 48 in the image forming apparatus 100. After being struck, it is abutted against the positioning roller (resist roller) vs. 49 and stopped.

When a manual feed tray is used, the paper feed roller is rotated to feed the recording medium P on the manual feed tray, and the paper feed tray P is manually fed after being separated one by one by the separation roller. It is introduced into the paper path and similarly abutted against the positioning roller vs. 49 and stopped.

After that, the positioning roller pair 49 is rotated in time with the formation of the full-color toner image on the intermediate transfer belt 10, and the recording medium P is placed at the secondary transfer position between the intermediate transfer belt 10 and the secondary transfer roller 16'. Be sent in. Then, the full-color toner image on the intermediate transfer belt 10 is collectively transferred onto the recording medium P.
The recording medium P on which the toner image is transferred is conveyed by the transport belt 24 and sent to the fixing device 25, and heat and pressure are applied by the fixing device 25 to fix the transferred toner image. It is discharged onto the paper discharge tray 57 by the discharge roller 56 and stacked.

In the case of double-sided copying, the recording medium P on which the image is fixed on one side is introduced into the sheet reversing mechanism 28, inverted, and then guided to the secondary transfer position again, the image is transferred to the back side, and the fixing device 25 After being fixed with, the paper is discharged onto the paper discharge tray 57 by the discharge roller 56.
Although the present invention has been described above based on the examples, the present invention is not limited to the ones described in the above examples, and various modifications can be made such as combining the inventions without departing from the gist thereof.

100 Image forming device 25 Fixing device 26 Fixing belt 27 Pressurizing member 31 Heating heater 34 Polishing roller drive gear 35 Drive transmission gear 50 Polishing unit 51 Polishing roller 52 Holding holder 53 Spring 800 Control unit

JP-A-2018-36616

Claims (11)

It is provided with a fixing belt that is stretched and rotated on a plurality of support members, a pressure member that forms a fixing nip portion between the fixing belts, and a belt polishing mechanism that polishes the surface of the fixing belt.
The belt polishing mechanism is
A polishing roller that is provided so as to be detachable from the fixing belt and is in pressure contact with the surface of the fixing belt.
An opposing member that faces the polishing roller via the fixing belt and forms a polishing nip portion between the polishing roller and the fixing belt.
A polishing roller rotation driving means for rotating the polishing roller is provided.
The polishing roller rotation driving means includes a first rotation driving member arranged coaxially with the polishing roller, and a second rotation driving member for transmitting a driving force to the first rotation driving member. ,
The polishing roller rotation drive means also serves as a contact / detachment drive unit for pressing and separating the polishing roller from the fixing belt.
A fixing device characterized in that. The polishing roller and the first rotation driving member must be rotatable around the second rotation driving member.
The fixing device according to claim 1. The polishing roller rotation driving means brings the polishing roller into pressure contact with the fixing belt when the polishing roller surface rotates in the forward direction with respect to the moving direction of the facing fixing belt surface.
The fixing device according to any one of claims 1 or 2, characterized in that The polishing roller rotation driving means separates the polishing roller from the fixing belt when the polishing roller surface rotates in a direction opposite to the moving direction of the facing fixing belt surface.
The fixing device according to any one of claims 1 to 3, wherein the fixing device is characterized by the above. In the belt polishing mechanism, when the polishing roller rotation driving means is stopped, the polishing roller is in pressure contact with the fixing belt, or the polishing roller is separated from the fixing belt.
The fixing device according to any one of claims 1 to 4, characterized in that. The polishing roller is rotationally driven at a speed different from the surface speed at the time of rotationally driving the fixing belt.
The fixing device according to any one of claims 1 to 5, characterized in that. The facing member is composed of at least one support member among the plurality of support members.
The fixing device according to any one of claims 1 to 6, characterized in that. The facing member is a fixing roller that forms the fixing nip portion between the pressing member and the fixing belt.
The fixing device according to claim 7, wherein the fixing device is characterized by the above. The facing member is a fixing member different from the plurality of supporting members.
The fixing device according to any one of claims 1 to 6, characterized in that. In a state where the polishing roller is in pressure contact with the fixing belt, the polishing roller faces the facing member via the fixing belt to form a polishing nip portion between the polishing roller and the fixing belt, and the fixing belt is formed by the fixing belt. The rotation locus is changed along the shape of at least a part of the peripheral surface of the polishing roller.
The fixing device according to any one of claims 1 to 9, wherein the fixing device is characterized by the above. An image forming apparatus comprising the fixing apparatus according to any one of claims 1 to 10.