JPH03293386A - Fixing device - Google Patents

Abstract

PURPOSE:To excellently fix a toner image by providing a grid-like contact preventing member between a sheet for applying a releasing agent to a rotor for fixing and a releasing agent absorbing member, and preventing the releasing agent from infiltrating in the sheet when the agent is not applied and uniformly applying it when it is applied. CONSTITUTION:The grid-like contact preventing member 28 is provided between a felt 31 as the releasing agent absorbing member by cappillarity of a releasing agent applying means 30 and a high polymer resin sheet 32 having minute through holes provided on the surface of the felt 31. In the case that the sheet 32 does not press-contact with a fixing roller 1, that means, at the time of not applying the agent, the member 28 prevents the contact of the sheet 32 with the felt 31, and when the sheet 32 is allowed to press-contact with the roller 1 by a driving means 17, the member 28 is buried in the felt 31, and the sheet 32 and the felt 31 regularly contact all over the surface, so that the releasing agent 15 uniformly infiltrates. Then, the sheet 32 uniformly applies the releasing agent to the roller 1, and the toner image 16 is excellently fixed on the transfer material P.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to a fixing device used for fixing an image transferred onto a transfer material in an image recording device such as a copying machine or a laser printer. The present invention relates to a fixing device that applies a release agent onto the surface of a fixing rotating body used for fixing using a release agent application means having a polymer resin sheet provided on the member.

[Evacuation I] Image recording devices such as copying machines and laser printers use a fixing device to fix images transferred onto a transfer material.

A conventional fixing device is shown in FIG.

In this example, the fixing device includes a pair of rollers: a fixing roller 1, which is a roller-shaped fixing rotating body, and a pressure roller 4, which is the same (roller-shaped elastic rotating body).

The fixing roller 1 includes a hollow core metal 2 made of aluminum, iron, or the like, coated with a room temperature vulcanizable silicone rubber layer 3.

A heater 7 such as a halogen lamp is disposed inside the fixing roller 1 to heat it.

The pressure roller 4 is made of a core metal 6 made of iron, stainless steel, etc., covered with a high temperature vulcanized silicone rubber layer 5, and a fluorine coating applied thereon.

In this example, a heater 7 such as a halogen lamp is also provided inside the pressure roller 4 .

The fixing device is further provided with a temperature sensing element 19 such as a thermistor and a temperature control circuit (not shown), and by controlling the voltage to the heater 7 based on the temperature value measured by the temperature sensing element 19, 19 maintains the surface temperature of, for example, the pressure roller 4 in contact with it at a predetermined value.

The transfer material P on which the toner image 16 formed by a well-known image forming method has been transferred is guided by an entry guide 8a in front of the fixing device, introduced between the fixing roller 1 and the pressure roller 4, and is introduced between the fixing roller 1 and the pressure roller 4. By applying pressure and heating between the toner image 16 and the pressure roller 4, the toner image 16 is fixed and fixed onto the transfer material P.

The transfer material P with the toner image fixed thereon is guided by a paper ejection guide 8b behind the fixing device and ejected to the outside of the image recording apparatus. Toner, paper dust, etc. adhering to the surface of the fixing roller 1 are cleaned and removed by a cleaner 9 provided on the fixing roller 1.

As shown in the figure, the fixing device is provided with a release agent applying means 10 for applying a release agent to the surface of the fixing roller 1.

The release agent application means 10 supports the felt 11 on a support plate 13 that is swingably attached to the fixing device main body by a shaft 20, and the lower end of the felt 11 is accommodated in the release agent tank 14. By immersing it in a liquid mold release agent 15, providing a spring 18 at the lower end of the support plate 13, and further providing a driving means 17 at the upper half of the support plate 13, the surface of the road half of the felt 11 is provided. A polymer resin sheet 12 having fine through-holes can be attached to and separated from the surface of the fixing roller 1 at will.

The polymer resin sheet 12 has a mold release agent 15 in a mold release agent tank 14.
The mold release agent 15 is passed from the felt 11 that has sucked up the mold release agent 15 to the fifth sheet 12 so that the mold release agent 15 penetrates into the sheet 12.
As shown in FIG. 6, which is a view taken along line B--B in the figure, the surrounding portion 12a is fixed to the felt 11 by heat-sealing.

The mold release agent 15 in the mold release agent tank 14η is sucked up by the felt 11 by capillary action, and is transferred to the polymer resin sheet 12.
When the sheet 12 on the felt 11 is brought into pressure contact with the fixing roller 1 by driving by the driving means 17, the amount of application is adjusted by the sheet 12, and it is supplied from the sheet 12 to the surface of the fixing roller 1. It is applied by

At this point, the polymer resin sheet 12 of the release agent applying means 10 is stretched and wrinkled due to pressure contact with the fixing roller 1. Since the felt 11 has elasticity, when the sheet 12 on the felt 11 is pressed against the fixing roller l during application of the release agent 15, the wrinkles in the sheet 12 are removed by the felt 11.
The sheet 12 and the felt 11 are brought into regular contact over the entire surface.

However, when the release agent 15 is not applied, there is no contact between the fixing roller 1 and the sheet 12, so that the sheet 12 and the felt 11 come into irregular contact due to wrinkles in the sheet 12. For this reason, the mold release agent 1 sucked up by the felt 11 when not applied.
5 does not permeate uniformly into the polymer resin sheet 12, and the release agent 15 does not permeate uniformly into the sheet 12 when it is not applied. cannot be applied evenly.

For this reason, conventionally, the fixing roller 1 contains a releasing agent.
5, the toner image 16 on the transfer material P is uneven.
This resulted in a deterioration in the fixing properties of the film.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a fixing device that can uniformly apply a release agent to a fixing roller using a release agent application means of the fixing device, thereby allowing a toner image to be properly fixed on a transfer material. It is to be.

The above-mentioned object for fixing images is achieved by a fixing device according to the present invention. In summary, the present invention allows a mold release agent sucked up by a mold release agent suction member by capillary action to permeate into a polymer resin sheet having fine through holes provided on the suction member, and then remove the mold release agent from the sheet. In the fixing device, the image on the transfer material is fixed by the rotary body while applying the release agent in the sheet to the rotary body by bringing the sheet into pressure contact with the fixing rotary body. A lattice-shaped contact prevention member for preventing contact between the sheet and the suction member when the mold release agent is not applied is provided between the sheet and the suction member. This is a fixing device.

good ml Examples of the present invention will be described below.

FIG. 1 is a configuration diagram showing an embodiment of the fixing device of the present invention;
FIG. 2 is a view taken along the line A--A in FIG. 1.

The fixing device of this embodiment includes a felt 31 as a release agent suction member using a capillary action of a release agent application means 30, and a polymer resin sheet 32 having fine through holes provided on the surface of the felt 31. A feature is that a grid-like contact prevention member 28 is provided between them, as shown in FIG. The rest of the structure of the fixing device of this embodiment is similar to the conventional fixing device shown in FIG. 5, and the same reference numerals in FIG. 1 as those in FIG. 5 indicate the same members.

As in the conventional case, the release agent applying means 30 includes a support plate 1 which is swingably attached to the main body of the fixing device by a shaft 20.
3 supports the felt 31, and immerses the lower end of the felt 31 in the liquid mold release agent 15 contained in the mold release agent tank 14. A spring 18 is provided at the lower end of the support plate 13 to further support the felt 31. By providing the driving means 17 in the upper half of the plate 13, the polymer resin sheet 32 provided on the surface of the road half of the felt 31 can be moved toward and away from the surface of the fixing roller 1. The polymer resin sheet 32 receives the mold release agent 15 from the felt 31 that has sucked up the mold release agent 15 in the mold release agent tank 14, and is placed in the second stage so that the mold release agent 15 permeates into the sheet 32. As shown in FIG. 2, the surrounding portion 32a is fixed to the felt 31 by heat-sealing.

Similarly, when the polymer resin sheet 32 is brought into pressure contact with the surface of the fixing roller 1 by driving by the driving means 17, the mold release agent 15 sucked up by the felt 31 from the mold release agent tank 14 is absorbed by the polymer resin. The coating amount is adjusted by the sheet 32 and applied to the surface of the fixing roller 1 .

The application of the release agent 15 to the fixing roller 1 is carried out by introducing the transfer material P onto which the toner image 16 has been transferred into between the fixing roller 1 and the pressure roller 4 while being guided by the entry guide 8a. The transfer material P, on which the toner image 16 has been fixed by pressure and heating between the fixing roller 1 and the pressure roller 4, passes between the fixing roller 1 and the pressure roller 4. This continues until it reaches a position 1 to 5 cm behind the release point.

In this example, Boa-Fron sheet (trade name, manufactured by Sumitomo Electric Industries, Ltd.), which is a tetrafluoroethylene sheet, was used as the polymer resin sheet 32.

The contact prevention member 28 is provided in a lattice shape between the felt 31 and the sheet 32 in the peripheral portion 32a of the fused portion of the sheet 32 and adhered to the felt 31 side. The contact prevention member 28 is made of thermoplastic resin in order to be able to follow the elongation of the felt 31 due to heat, and in this embodiment, it is made of polypropylene resin.

In the present invention, the contact prevention member 28 is provided between the polymer resin sheet 31 and the felt 32 because the contact prevention member 28 is provided between the felt 31 and the polymer resin sheet 32 when the release agent 15 is not applied to the fixing roller 1. This is to prevent contact and allow the release agent 15 to permeate into the sheet 32 from the felt 31 when not applied.

The reason why the contact prevention members 28 are arranged in a lattice pattern is that when the release agent 15 is applied, the fixing roller 1 and the sheet 32 are pressed against each other.
The blocking member 28 is buried in the surface of the stretchable felt 31, and the sheet 32 and the felt 31 are brought into regular contact over the entire surface, so that the release agent 15 is transferred from the felt 31 to the sheet 32.
This is to ensure uniform penetration. Therefore, it is preferable that the grid of the contact prevention member 28 is made as thin as possible within a range that can prevent the sheet 31 from coming into contact with the felt 32 when it is not in contact with the fixing roller 1.

The fixing device of the present invention is configured as described above, and according to this, when the release agent 15 is not applied when the polymer resin sheet 32 of the release agent application means 30 is not in pressure contact with the fixing roller 1,
The contact prevention member 28 prevents the felt 31 and the sheet 32 from coming into contact with each other, and the felt 3 is removed from the release agent tank 14.
1 prevents the release agent 15 sucked up from penetrating into the sheet 32.

When the polymer resin sheet 32 comes into pressure contact with the fixing roller 1 during application of the release agent 15, the contact prevention member 28 is buried in the surface of the felt 31 due to the pressure contact, and the sheet 32 and the felt 31 are arranged regularly over the entire surface. felt 31
The mold release agent 15 is uniformly permeated into the sheet 32.

Therefore, the release agent 15 can be uniformly applied from the sheet 32 onto the fixing roller 1 without causing uneven coating when applying the release agent 15, and therefore the toner image 16 can be transferred onto the transfer material P in a good manner. can be established.

FIG. 3 is a configuration diagram showing another embodiment of the fixing device of the present invention.

The fixing device of this embodiment includes a support plate 1 of a release agent applying means 30.
3 and felt 31 are curved along the circumferential surface of the fixing roller 1, so that the polymer resin sheet 32 made of a boa-flon sheet is arranged on the circumferential surface of the fixing roller 1 at the same nip. felt 31 and sheet 3
Other configurations of this embodiment, such as providing a contact prevention member 28 between the third
In the drawings, the same reference numerals as in FIG. 1 indicate the same members.

According to this embodiment, since the polymer resin sheet 32 is arranged on the circumferential surface of the fixing roller 1 with the same nip, the fixing roller 1
When applying the release agent 15 to the felt 31 from within the release agent tank 14, the entire surface of the sheet 32 can be brought into pressure contact with the fixing roller 1, thereby preventing partial deterioration of the sheet 32.
The release agent 15 that has been sucked up and permeated into the sheet 32 can be applied more stably and uniformly onto the fixing roller l.

FIG. 4 is a configuration diagram showing still another embodiment of the fixing device of the present invention.

The fixing device of this embodiment includes a support plate 1 of a release agent applying means 30.
3 is characterized in that only the upper half of the felt 31 is fixed. The other configurations of this embodiment, such as providing the contact prevention member 28 between the felt 31 and the sheet 32, are the same as the fixing device shown in FIG. 1, and the reference numerals in FIG. The same reference numerals indicate the same members.

In this embodiment, by fixing only the upper half of the felt 31 to the support plate 13, when the polymer resin sheet 32 comes into pressure contact with the fixing roller 1, the felt 31 and the sheet 3
In order to prevent the felt 31 from wrapping around the fixing roller 1, a presser 34 provided at the lower end of the support plate 13
The unfixed part of is tethered.

According to this embodiment, only the upper half of the felt 31 is fixed to the support plate 13 and the felt 31 is not fixed to the lower end of the support plate 13, so when applying the release agent 15 to the fixing roller 1. When the sheet 32 is brought into pressure contact with the fixing roller 1, the stress applied to the sheet 32 and the felt 31 from the fixing roller 1 can be dissipated downward, thereby preventing deterioration of the sheet 32 and the felt 31, and releasing the release agent in the tank 14. The release agent 15, which has been sucked up from inside by the felt 31 and permeated into the sheet 32, can be more stably and uniformly applied onto the fixing roller 1 as in the embodiment shown in FIG.

As described above, according to the present invention, by providing the grid-shaped contact prevention member 28 between the polymer resin sheet 32 and the felt 31 of the release agent application means of the fixing device, the release agent 1
No coating unevenness occurred during coating of sheet 32.
The release agent 15 can be uniformly applied onto the fixing roller 1, and therefore the toner image 16 can be well fixed onto the transfer material P.

Generally, in a color image forming apparatus, the toner layer that forms the image consists of three or more layers of magenta, yellow, and cyan, and these toners have poor meltability and color mixing properties when heated. It is necessary that the
Since it is preferable to use sharp-melt toner with a low softening point and low melt viscosity, it is necessary to apply a large amount of a low-viscosity release agent to ensure the life of the fixing roller of the fixing device. be. For this reason, in color image forming apparatuses, uneven application of the release agent 15 to the fixing roller 1 clearly appears on the image, and the life of the fixing roller 1 is shortened.

According to the present invention, when applied to a fixing device of such a color image forming apparatus, a release agent is uniformly applied to the fixing roller without causing uneven coating, and a good toner image is formed on a transfer material. It is possible to fix the image on the image, and also ensure the life of the fixing roller.

Light: 1 ohm By infiltrating a polymer resin sheet having fine through holes and pressing the sheet against a fixing rotating body, the releasing agent in the sheet is applied to the rotating body while being transferred by the rotating body. When fixing an image on a material, a grid-like contact prevention member is provided to prevent contact between the sheet and the suction member when the release agent is not applied to the rotating body. It is installed between the sheet and the suction member to prevent the release agent from permeating into the sheet when no release agent is applied, which causes irregular penetration of the release agent. By uniformly applying the release agent to the body, the toner image can be well fixed on the transfer material.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of a fixing device of the present invention. FIG. 2 is a view taken along the line A--A in FIG. 1. FIG. 3 is a configuration diagram showing another embodiment of the fixing device of the present invention. FIG. 4 is a configuration diagram showing still another embodiment of the fixing device of the present invention. FIG. 5 is a configuration diagram showing a conventional fixing device. FIG. 6 is a view taken along line E-B in FIG. 5. 5 8 0 1 2: Fixing roller: Pressure roller: Release agent: Contact prevention member: Release agent application means: Polymer resin sheet: Felt Figure 2 Figure 3 Figure 5

Claims (1)

[Claims] 1) The release agent sucked up by the release agent suction member by capillary action is infiltrated into a polymer resin sheet having fine through holes provided on the suction member, and the sheet is transferred to a fixing rotating body. In the fixing device, the image on the transfer material is fixed by the rotating body while applying the releasing agent in the sheet to the rotating body by applying the releasing agent to the rotating body. A fixing device characterized in that a grid-shaped contact prevention member is provided between the sheet and the suction member to prevent contact between the sheet and the suction member when no release agent is applied.