JP3838293B2 - Fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device for heating and pressure-fixing an unfixed image in an image information recording apparatus such as a copying machine, a printer, and a facsimile, and more particularly, includes a plurality of tiltable steering rolls for adjusting meandering. The present invention relates to an improvement in a belt fixing device in which roll groups are arranged in parallel, endless belts are looped over these roll groups, and the endless belt circulates and rotates.
[0002]
[Prior art]
Conventionally, as this type of belt fixing device, a fixing roller and an endless belt arranged in pressure contact with the fixing roll are known, and fixing is performed in a nip region between them.
This is because a plurality of support roll groups are arranged in parallel, a heat-resistant endless belt is looped over these support roll groups, and the belt is circulated and rotated, thereby unfixed toner between the fixing roll and the endless belt. A sheet carrying a sheet is conveyed by nip.
[0003]
Conventionally, in this type of belt fixing device, from the viewpoint of effectively avoiding problems such as belt breakage and paper wrinkling, the endless belt is accurately conveyed along a predetermined route. Therefore, it is an important technical problem to effectively prevent meandering in the direction (width direction) orthogonal to the moving direction of the endless belt.
However, considering the incompleteness of molding of the endless belt and the support roll, the parallelism of the support roll on which the endless belt is stretched, and the like, in the past, a belt meandering adjustment device that prevents meandering in the width direction of the belt Is provided.
[0004]
Conventionally, as this type of belt fixing device, for example, one of a roll group on which an endless belt made of polyimide is stretched is a tiltable metal steering roll, and the position of the steering roll is adjusted by an alignment adjusting device. There is known one that adjusts the meandering of the belt (see JP-A-3-241377).
[0005]
[Problems to be solved by the invention]
However, in this type of fixing device, there has been a technical problem that the metal steering roll and the endless belt made of polyimide are slippery, and the operation of the steering roll is difficult to be transmitted to the endless belt.
Further, in the state where the endless belt meanders, the endless belt itself often swells, and the contact area with the metal steering roll is not sufficient, so that the control operation of the steering roll is difficult to be transmitted to the endless belt. Technical issues also arise.
[0006]
The present invention has been made to solve the above technical problems, and provides a fixing device capable of performing stable endless belt meandering adjustment control while maintaining good recording sheet peeling performance. Is.
[0007]
[Means for Solving the Problems]
That is, according to the present invention, as shown in FIG. 1 (a), a plurality of roll groups 1 including at least a tiltable steering roll 1s for adjusting meandering are arranged in parallel, and an endless belt 2 is attached to these roll groups 1. On the other hand, a heating roll is disposed in pressure contact with a portion of the endless belt 2 that is stretched between the rolls excluding the steering roll 1s, and the endless belt 2 along the axial direction of the steering roll 1s is tilted by the steering roll 1s. In the fixing device that circulates and rotates the endless belt 2 while regulating the position, and heats and presses and fixes an unfixed image on the recording sheet in the pressure nip region between the heating roll and the endless belt 2, the steering roll 1s the heat resistant elastic body made of a material having at least an oil absorbing ability is included Rutotomoni surface at least mirror-like gold High friction and is provided with an elastic covering layer 3 to be elastically deformed along the shape of the endless belt 2 to the extent that the rough enable walk adjustment of the endless belt 2 than among the rolls 1, the steering roll 1s with the pressure roll adjacent the upstream side in the movement direction of the endless belt 2 makes the endless belt 2 pressurization clamping between the heating roll, an endless belt Te at the entrance before the press nip region between the heating roll and the endless belt 2 (2) The lubricating oil applied to the back surface is absorbed by the steering roll 1s through the pressure roll .
[0008]
In such technical means, the belt fixing device to which the present application is applied is one in which a roll group 1 including a steering roll 1 s having an elastic coating layer 3 for adjusting meandering circulates and rotates an endless belt 2. If present, the endless belt may be used for pressurization or heating.
That is, in the present invention, in the embodiment in which the endless belt 2 is used for heating, a heating source may be provided inside or outside the endless belt 2.
[0009]
On the other hand, in the embodiment in which the endless belt 2 is used for pressurization in the present invention, as shown in FIG. 1B, a heating roll 4 having an elastic layer 5 and a tiltable steering for at least meandering adjustment are provided. An endless belt 2 that is stretched over a plurality of roll groups 1 including a roll 1s, is in pressure contact with the heating roll 4 at a portion spanned between rolls excluding the steering roll 1s, and rolls together with the heating roll 4. A pressure member 6 that is provided inside the endless belt 2 and presses the endless belt 2 toward the heating roll 4, and regulates the position of the endless belt 2 along the axial direction of the steering roll 1 s by tilting of the steering roll 1 s. A fixing device that heats and presses and fixes an unfixed image on a recording sheet in a pressure nip region between the heating roll 4 and the endless belt 2, Over to Le 1s, heat-resistant elastic body made of a material having at least an oil absorbing ability is included Rutotomoni, surface high friction and to the extent to allow at least mirror-like rough walk adjustment of the endless belt 2 than metal An elastic coating layer 3 that elastically deforms along the shape of the endless belt 2 is provided. Among the roll group 1, a pressure roll adjacent to the steering roll 1s on the upstream side in the moving direction of the endless belt 2 is a heating roll. the endless belt 2 with make pressurization clamping between 4, a lubricating oil is applied to the endless belt 2 back surface Te at the entrance before the press nip region between the heating roll 4 and the endless belt 2 via the pressure roll What is necessary is just to make it absorb with the steering roll 1s .
[0010]
In the present invention, as the elastic coating layer 3 of the steering roll 1s, for example, a metal roll core material is coated with a heat resistant elastic body, and a metal roll core material is coated with a heat resistant elastic body. Further, a material coated with a surface coat layer may be appropriately selected .
[0011]
Further, in order to make transfer control by the steering roll 1s to the endless belt 2, the surface of the steering roll 1s it is necessary to elastically deform along the high friction and the endless belt 2 shape.
The degree of high friction of the steering roll 1s is rougher than that of at least a mirror-like metal, and is preferably about the surface state normally possessed by silicon rubber or a similar material. As the steering roll 1s, the meandering adjustment of the endless belt 2 is possible. It is appropriately selected within a certain range.
[0012]
Furthermore, in this type of belt fixing device, from the viewpoint of reducing the sliding resistance between the endless belt 2 and the pressure member 6, a lubricant such as silicone oil is applied to the inner surface of the endless belt 2. It is preferable to apply.
However, in this type, there is a concern that the friction between the steering roll 1s and the endless belt 2 becomes low, and the control of the steering roll 1s is not easily transmitted to the endless belt 2. From the viewpoint of avoiding such a concern, it is preferable to use an elastic covering layer 3 having an oil absorption ability.
Here, in the aspect in which the heat resistant elastic body itself constitutes the elastic coating layer 3, the heat resistant elastic body itself is required to have an oil absorption capability. In the embodiment having the surface coat layer on the surface, the surface coat layer itself may be composed of an oil-absorbing material, or the surface-coating layer is permeable and the heat-resistant elastic body absorbs oil. You may be comprised by what has property.
Further, the elastic coating layer 3 is made of silicon rubber (HTV: heat vulcanizing silicone rubber, RTV: room temperature curable liquid silicone rubber, LIM (LSR) from the viewpoint of a material having elasticity and oil absorption. ): Liquid injection-molded silicone rubber, etc.) and similar materials are preferably used.
[0013]
Next, the operation of the technical means described above will be described.
In FIG. 1A, when the endless belt 2 stretched around the roll group 1 including the steering roll 1s rotates, imperfect molding of the endless belt 2 and the roll group 1 and the parallelism of the roll group 1 are performed. Due to the incompleteness of the belt, the endless belt 2 is swelled.
In order to cancel this undulation, the steering roll 1s is controlled. At this time, since the surface of the steering roll 1s has elasticity, a large contact area with the endless belt 2 causing the undulation can be obtained. Since the surface of the steering roll 1s is provided with the elastic coating layer 3 with high friction, the friction between the steering roll 1s and the endless belt 2 is high, and the steering roll 1s has a sufficient force to control the endless belt 2. It is transmitted.
As a result, the undulation generated in the endless belt 2 is effectively suppressed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.
FIG. 2 shows an embodiment to which the present invention is applied.
In the figure, the fixing device according to the present embodiment includes a heating roll 21 and an endless belt 16 disposed in pressure contact with the heating roll 21.
[0015]
In the present embodiment, the heating roll 21 includes a stainless steel cylindrical core 23 that covers a heating source 22 made of, for example, a halogen lamp, and a heat-resistant elastic layer 24 made of silicon rubber that covers the cylindrical core 23.
[0016]
On the other hand, the endless belt 16 is made of, for example, a polyimide film or the like, is stretched around the support rolls 11, 14, and 15 and is press-contacted to the heating roll 21 with a predetermined nip width.
[0017]
Further, in the present embodiment, the support roll 14 is made of stainless steel, and also serves as a pressure roll disposed at the exit of the contact nip area 41 between the heating roll 21 and the endless belt 16, and is provided by a spring (not shown). It is urged toward the heating roll 21. Here, the support roll 14 does not require a peeling claw or the like even when the unfixed toner 32 is fixed to the recording sheet 31 having a thin paper thickness and a weak paper, for example. This enables so-called self-stripping, in which the recording sheet 31 can be peeled off without using an apparatus.
Further, in this embodiment, the support roll 11 also serves as a steering roll for preventing the endless belt 16 from meandering, and an elastic coating made of a stainless steel cylindrical core 12 and silicon rubber covering the cylindrical core 12. Layer 13.
Furthermore, a pressure pad 18 made of an elastic body is disposed in pressure contact with the inner side of the endless belt 16, and this pressure pad 18 is provided on the base 17 toward the heating roll 21 by a spring not shown. It is energized.
Further, on the upstream side of the pressure pad 18 inside the endless belt 16, there is provided an application blade 19 for applying a lubricant 51 made of, for example, amine-modified silicone oil, for example, impregnated with the lubricant 51 in advance.
[0018]
Next, the operation of the present embodiment will be described.
When the recording sheet 31 carrying the unfixed toner 32 passes through the contact nip region 41, the unfixed toner 32 includes the heating roll 21, the support roll (pressure roll) 14, the endless belt 16, and the pressure pad 18. Is fixed on the recording sheet 31 by heat and pressure received from the recording medium 31.
[0019]
When the recording sheet 31 passes through the contact nip area 41, the sliding resistance between the endless belt 16 and the pressure pad 18 is increased, and the rolling of the endless belt 16 is hindered. In order to prevent this, the lubricating oil 51 is applied to the inside of the endless belt 16 from the application blade 19 provided on the upstream side of the pressure pad 18 inside the endless belt 16.
[0020]
However, the endless belt 16 tends to meander due to incomplete molding of the endless belt 16 and the support rolls 11, 14, 15, and incompleteness such as parallelism of the support rolls.
At this time, in order to prevent the endless belt 16 from meandering, meandering adjustment control by the support roll (steering roll) 11 is performed.
Here, since the surface of the steering roll 11 is covered with an elastic coating layer 13 made of silicon rubber, the steering roll 11 comes into contact with the endless belt 16 with high friction, and as shown in FIG. Even when the endless belt 16 swells, the elastic coating layer 13 on the surface of the steering roll 11 is elastically deformed along the shape of the endless belt 16, so that the contact area 61 between the steering roll 11 and the endless belt 16 is large. The endless belt 16 is controlled to meander by the friction force between them, and the meandering of the endless belt 16 is effectively suppressed.
Furthermore, in the present embodiment, the elastic coating layer 13 of the steering roll 11 is made of silicon rubber with good oil absorption, so that the elastic coating layer 13 is a lubricating oil 51 applied to the inside of the endless belt 16. Absorbs. For this reason, a decrease in the frictional force due to the lubricating oil 51 is effectively prevented, and the frictional force between the steering roll 11 and the endless belt 16 does not decrease, and stable meandering adjustment control of the endless belt 16 is achieved. Done.
[0021]
【The invention's effect】
As described above, according to the present invention, the shape of the endless belt is high in friction so that the steering roll is provided with an elastic coating layer and the surface thereof is rougher than at least a mirror-like metal and the endless belt can be adjusted. The endless belt surface and the elastic coating layer can be brought into contact with high friction, and the elastic coating layer is elastically deformed along the endless belt shape to ensure a sufficient contact area. can do. For this reason, even if an inelastic endless belt such as polyimide is used, it can be stretched uniformly regardless of the endless belt performance, and stable endless belt meandering adjustment control is possible even when the endless belt meanders. It can be carried out.
Further, among the plurality of rolls to pass over the endless belt, and the endless belt between the heating roll to the pressure roll adjacent the upstream side in the movement direction of the endless belt against the steering roller to make pressurization clamping Therefore, the recording sheet peeling performance can be kept good while ensuring the meandering adjustment control operation of the endless belt.
In particular, in the present invention, since an elastic coating layer having good oil absorption is used for the steering roll, it is possible to effectively absorb the lubricating oil applied to the back surface of the endless belt, and accordingly, the steering roll and the endless belt can be absorbed. A reduction in frictional force with the belt can be prevented, and more stable meandering adjustment control can be performed.
Furthermore, in the present invention, since the elastic coating layer of the steering roll includes a heat-resistant elastic body, this elastic coating layer exhibits a heat insulating action, and accordingly, the amount of heat taken away from the endless belt is reduced, There is also a secondary effect of improving the thermal efficiency of the fixing nip area.
[Brief description of the drawings]
FIGS. 1A and 1B are explanatory views showing an outline of a fixing device according to the present invention.
FIG. 2 is an explanatory diagram showing an embodiment of a belt fixing device to which the present invention is applied.
FIG. 3 is an explanatory view showing an enlargement of a steering roll according to FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Roll group, 1s ... Steering roll, 2 ... Endless belt, 3 ... Elastic coating layer, 4 ... Heating roll, 5 ... Elastic layer, 6 ... Pressure member, 11 ... Steering roll, 13 ... Elastic coating layer, 16 ... Endless belt, 18 ... pressure pad, 19 ... coating blade , 21 ... heating roll, 24 ... heat resistant elastic layer

Claims (3)

A plurality of roll groups including at least a tiltable steering roll for adjusting meandering are arranged in parallel, and an endless belt is spanned between these roll groups, while the endless belt is spanned between rolls excluding the steering roll. A heating roll is press-contacted at the site, and the endless belt is circulated and rotated while regulating the position of the endless belt along the axial direction of the steering roll by tilting of the steering roll, so that the heating roll and the endless belt are brought into a pressure nip region In a fixing device that heats and presses and fixes an unfixed image on a recording sheet,
Wherein the steering roller, the heat-resistant elastic body made of a material having at least an oil absorbing ability is included Rutotomoni, surface high friction and endless enough to permit walk adjustment of coarse endless belt than at least mirror-like metal An elastic covering layer elastically deforming along the shape of the belt ;
Of the rolls, pressurized nip of the endless belt between the heating roll to the pressure roll adjacent the upstream side in the movement direction of the endless belt with make pressurization clamping the steering roll, a heating roll and the endless belt a fixing device, wherein a lubricant is applied to the endless belt back surface Te at the entrance before the band was set to be absorbed by the steering roller via the pressure roll. A heating roll having an elastic layer;
An endless belt that is stretched over a plurality of roll groups including at least a tiltable steering roll for adjusting meandering, and is in contact with the heating roll and rolls together with the heating roll at a portion spanned between the rolls excluding the steering roll. When,
A pressure member that is provided inside the endless belt and presses the endless belt toward the heating roll;
A fixing device that heats and presses and fixes an unfixed image on a recording sheet in a pressure nip region between the heating roll and the endless belt while regulating the position of the endless belt along the axial direction of the steering roll by tilting the steering roll. Because
Wherein the steering roller, the heat-resistant elastic body made of a material having at least an oil absorbing ability is included Rutotomoni, surface high friction and endless enough to permit walk adjustment of coarse endless belt than at least mirror-like metal An elastic covering layer elastically deforming along the shape of the belt ;
Of the rolls, pressurized nip of the endless belt between the heating roll to the pressure roll adjacent the upstream side in the movement direction of the endless belt with make pressurization clamping the steering roll, a heating roll and the endless belt a fixing device, wherein a lubricant is applied to the endless belt back surface Te at the entrance before the band was set to be absorbed by the steering roller via the pressure roll. The fixing device according to claim 1 or 2,
A fixing device, wherein the elastic coating layer is made of silicon rubber.

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