JPH1124481A - Fixing device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a fixing device capable of preventing generation of chattering noise even when a release material application unit is mounted on a pressure roller. A heating means is provided for each of a fixing roller and a pressure roller, and the pressure roller has an oil application felt and an oil regulating blade in a rotation direction thereof.
2 are sequentially provided, and the oil regulating blade 12 is in contact with the oil-applied felt 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrophotographic printer, a copying machine, a facsimile, and the like, and more particularly to a fixing apparatus most suitable for a full-color image forming apparatus.

[0002]

2. Description of the Related Art In a full-color image forming apparatus such as a full-color copying machine, the surface layers of a fixing roller and a pressure roller are made of a highly releasable elastic member such as silicone rubber for double-side fixing. Usually, a means for applying a release material such as silicone oil is provided on the fixing roller side, and the surface of the roller is considered so that the release property is always maintained.
On the other hand, in the pressure roller, since oil flows from the fixing roller, the release material applying means is often omitted in consideration of cost.

However, when the sheet interval is short, as in a high-speed machine, the release agent from the fixing roller is not supplied to the pressure roller, causing a problem that the releasability of the surface of the pressure roller is reduced. Normally, the pressure roller does not come into contact with the unfixed toner image, but if the releasability of the pressure roller is reduced, paper powder and calcium carbonate contained in the transfer paper adhere to the surface. If, for example, calcium carbonate adheres to the surface of the pressure roller, the next time the OHP sheet is passed, the calcium carbonate adheres to the OHP sheet and causes a whitening phenomenon, thereby causing poor transmission, or causing an additional problem. There has been a problem that the friction coefficient between the pressure roller and the surface of the thermistor is increased to generate chatter noise.

[0004] In order to solve this problem, a release material applying means is also mounted on the pressure roller side so as to obtain a predetermined release property. As an example of this release material applying means,
It is known to dispose an oil-impregnated felt and an oil regulating blade made of fluorine rubber or the like downstream of the felt.

[0005]

However, when the pressure roller is equipped with a release material applying means, fine particles such as paper powder and calcium carbonate accumulate on the oil regulating blade, increasing the friction coefficient and causing chattering noise. May occur.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a fixing device that can prevent generation of chattering noise even when a release material applying unit is mounted on a pressure roller.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a rotating fixing roller and a pressure roller which is brought into contact with the fixing roller with a predetermined pressure. In a fixing device in which a transfer material onto which a toner image has been transferred is inserted and heated to melt and fuse the toner image onto the transfer material, a heating unit is provided for each of the fixing roller and the pressure roller. The pressure roller is provided with a release material applying member and a regulating member sequentially in the rotation direction, and the regulating member is in contact with the release material applying member.

The present invention is effective when a cushioning material is provided which acts on a part of the release material applying member which comes into contact with the regulating member. Further, the present invention is effective when both the fixing roller and the pressure roller have a rotation driving unit.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view showing an embodiment of the fixing device according to the present invention.

In FIG. 1, reference numeral 1 denotes a fixing roller, 2 denotes a pressing roller, and both the fixing roller 1 and the pressing roller 2 are covered with an elastic layer. Have. The surface cleaning roller 7 of the fixing roller 1 is in contact with the cleaning roller 7, and the cleaning roller 7 is in contact with a scraper 8 that scrapes foreign substances and the like attached to the roller. The transfer material carrying the toner is supplied to the fixing roller 1
The toner image is fixed on the transfer material through a nip portion pressed by the pressure roller 2 and the pressure roller 2. On the other hand, the fixing roller 1 is in contact with an oil application felt 5 as a release agent applying means, and an oil regulating blade 6 for regulating the amount of oil downstream of the felt. The oil is a dimethyl silicone oil with a viscosity of 300 CS,
The oil application amount can be regulated to 2 mg / A4 size to 10 mg / A4 size.

On the other hand, as shown in FIG. 2, an oil-applied felt 16 as a releasing agent applying means is also in contact with the pressure roller 2, and the amount of oil is regulated downstream of the oil-applied felt 16. An oil regulating blade 12 is provided. As shown in FIG. 2, the oil regulating blade 12 is fastened to the holder 14 by a stepped screw 13, and the stepped screw 13 is fastened at only one central position. Thus, the oil regulating blade 12 can swing about the stepped screw 13 with respect to the pressure roller 2, and when a spring 15 described later is pressed,
The oil regulating blade 12 can abut uniformly over the entire length.

Here, the pressure roller 2 is rotating in the direction of arrow A, and the oil of the oil application felt 16 repeats circulation while being regulated by the oil regulating blade 12 as shown by arrow B. The amount of oil applied at this time can be controlled by the pressing force of the spring 15. That is, since the holder 14 rotates clockwise about the fulcrum 18, the blade 12 can be brought into contact with the pressure roller 2 with a pressing force corresponding to the spring force of the spring 15, and the amount of oil applied is It can be controlled by the pressing force of the spring 15. The greater the pressure, the more the amount of applied oil can be reduced. Further, the rear end of the holder 14 is brought into contact with the oil-applied felt 16 so as to be slightly bitten. The biting amount ΔL of the contact portion is set to such an extent that the pressing force of the oil regulating blade 12 is not hindered.

The oil-coated felt 16 of this embodiment is provided such that two felts 16a and 16b are overlapped, and is made of a heat-resistant non-woven fiber such as Nomex (trade name), Comex (trade name), or the like. And has a cushioning property depending on the density of the fiber.

The fixing device having the above-described structure is provided with oil applying means on the pressure roller 2 so that the pressure roller 2
Of the oil regulating blade 12
When particulate matter such as paper powder or calcium carbonate accumulates in the water, a chattering sound is generated. The chattering noise is generated when the oil regulating blade 12 vibrates.

Therefore, in the present embodiment, as described above, the holder 14 supporting the oil regulating blade 12 is used.
Is in contact with the oil-applied felt 16. Due to this contact, the vibration of the oil regulating blade 12 that causes chattering noise is suppressed by the oil-applied felt 16 having cushioning properties, and the occurrence of chattering noise can be prevented with a simple configuration.

As shown in FIG. 2, the oil-applied felt 16 acts on the rear end of the holder 14 supporting the oil regulating blade 12 in order to more reliably provide the oil regulating blade 12 with a damping action. Sponge 1 at the position
7 are provided. In this example, the sponge 17 is the felt 1
It is mounted between 6a and 16b, thereby enhancing the cushioning properties of the oil-applied felt 16. The sponge 17 is located between the rear end of the holder 14 and the felt 16a.
The effect can be expected even if provided between the felt 16b and the bottom plate of the fixing unit.

By the way, the oil as the release agent causes a problem such as poor paper feeding on both sides due to the adhesion thereof. For this reason, in recent years, there has been a demand for a fixing device with a reduced oil application amount. I have. When oil is applied to the pressure roller 2 as described above, it is indispensable to reduce the amount of oil applied.

In the case of the pressure roller 2 described above, the oil application amount can be suppressed by bringing the oil regulating blade 12 into contact with a spring 15 having an increased spring force. Since the roller 1 is driven to rotate, and the pressure roller 2 is driven to rotate by the fixing roller 1, the rotation of the pressure roller 2 lacks smoothness, and in some cases, a rotation failure occurs.

Therefore, in the present invention, the fixing roller 1 and the pressure roller are fixed so that the rotation of the pressure roller 2 can be prevented even if the oil regulating blade 12 is pressed against the pressure roller 2 in order to suppress the oil application amount. 2 is provided with a rotation drive means, and FIG. 3 is a cross-sectional view showing one example thereof.

In FIG. 3, the fixing roller 1 is rotationally driven by a fixing drive input gear 20 on the rear side of the shaft 1a. The front side of the shaft 1a is
The fixing gear 21 is arranged inside of a. The fixing gear 21 engages with the shaft 1a in a D-hole shape (not shown), and is configured to be detachable in the thrust direction at the time of replacement. Further, a heat insulating bush 23 and a fixing bearing 22 are set on the shaft 1a, and the fixing gear 21 and the C ring 25 and the shaft 1a are attached to the boss so that there is no play at the boss portion. Furthermore,
Since the fixing bearing 22 is attached to the fixing side plate 24a by the bearing stopper 26 and extends in the direction of arrow C when the fixing roller 1 is thermally expanded, the thrust position of the fixing gear 21 can be small.

On the other hand, the fixing roller 21
The pressurizing gear 27 is attached to a position corresponding to.
As shown, the gear 27 and the shaft 2a of the pressure roller 2 are fitted together with a boss 27 extending to a pressure bearing 28.
a, the fixing gear 21 is attached by a D-hole shape in the same manner as the fixing gear 21. The boss portion 27a functions as a spacer that also serves as a positioning up to a position where the pressure bearing 28 and the gear 27 mesh with each other. By doing so, the play of the meshing portions of the gears 21 and 27 is suppressed, so that the tooth width of the gears can be set as thin as 35 mm and can be mounted in the fixing side plate. Gears 21 and 27 are spur gears,
The number of teeth is 60Z for both the fixing gear 21 and the pressure gear 27,
It rotates at a constant speed with a peripheral speed ratio of 1: 1.

In this manner, by providing the pressure roller 2 with the rotation driving means, the pressure of the oil regulating blade 12 is increased, and the amount of applied oil can be suppressed. Note that the specifications of the fixing device according to the present embodiment will be additionally described. The fixing roller 1 has a cored bar coated with three layers of elastic rubber.
The base layer is coated with HTV rubber, the intermediate layer is coated with fluorine-based rubber, and the surface layer is coated with LTV rubber having high releasability. The pressure roller 2 is also covered with three layers of elastic rubber, like the fixing roller 1, to support both sides. Further, the outer diameter of the fixing roller 1 is set to 60 mm, the thickness of the elastic rubber layer is set to 1 to 3 mm, and the pinch amount is set to 0.05 mm. The outer diameter of the pressure roller 1 is set to 60 mm, the thickness of the elastic rubber layer is set to 1 to 3 mm, and the pinch amount is set to 0.06 mm. The thickness of the intermediate layer is 10
μ to 100 μ, the surface layer is 30 to 200 μ, and the rest is the thickness of the base layer. The nip width is 9.5 mm, and the fixing speed is 180 mm / s in the plain paper mode (nip time is 0.1 mm).
053 sec), and 90 mm / s in the thick paper mode.

[0023]

According to the first aspect of the present invention, it is possible to prevent chattering noise caused by the vibration of the regulating member with a simple structure in which the regulating member comes into contact with the release material applying member.

According to the configuration of the second aspect, the vibration of the regulating member can be suppressed more reliably by the cushion material.
According to the third aspect of the present invention, the pressure roller is provided with the rotation driving means, so that the pressing force of the regulating member to the pressure roller is increased to suppress the oil application amount, so that the pressure roller can be stably operated. Can rotate.

[Brief description of the drawings]

FIG. 1 is a side view illustrating an embodiment of a fixing device according to the present invention.

FIG. 2 is an enlarged explanatory view of a main part of FIG. 1;

FIG. 3 is a sectional view showing another embodiment of the fixing device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 12 Oil regulating blade 16 Oil application felt 21 Fixing gear 27 Pressure gear

Claims (3)

[Claims] An image forming apparatus comprising: a fixing roller that is rotated; and a pressure roller that is brought into contact with the fixing roller with a predetermined pressure, and a transfer material on which a toner image is transferred is inserted between the two rollers. In a fixing device that heats and melts a toner image and fuses the toner image onto a transfer material, heating means is provided for each of the fixing roller and the pressure roller, and the pressure roller has a release material applying member and A fixing device, wherein a regulating member is sequentially provided, and the regulating member is in contact with a release material applying member. 2. The fixing device according to claim 1, further comprising a cushion member acting on a portion of the release material applying member that comes into contact with the regulating member. 3. The fixing device according to claim 1, wherein both the fixing roller and the pressure roller include a rotation driving unit.