JPH08241005A - Fixing device - Google Patents

Abstract

PURPOSE: To provide a fixing device constituted so that a supply member is hardly soiled and the variance of the soiling state of the supply member is suppressed according to the change of the soiling state of a fixing roller in a shaft center direction. CONSTITUTION: The supply roller 4 is provided with a porous surface layer whose quality is the same as the mold-releasing layer 1a of the fixing roller 1. Besides, the roller 4 is provided with an oil supply quantity change means changing the quantity of oil supplied to the roller 1 by changing the numerical aperture of the surface layer in the shaft center direction of the roller 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing roller having a release layer on its peripheral surface, and a pressure rotator contacting the fixing roller.
A transfer member that is in contact with the fixing roller along the axial direction and supplies oil over substantially the entire effective fixing width of the fixing roller, and a transfer material carrying an unfixed toner image with the fixing roller. The present invention relates to a fixing device that heats and presses an unfixed toner image on a transfer material to fix the unfixed toner image on the transfer material by sandwiching and conveying it with the pressure rotating body.

[0002]

2. Description of the Related Art A fixing device of the above type is well known and is often attached to an image forming apparatus using powder toner such as a printer, a copying machine and a facsimile. In this type of fixing device, the toner is melted by the heat of the fixing roller and fused to the transfer material. At this time, if the releasing property of the fixing roller is bad,
An offset occurs in which some toner adheres to the fixing roller. Therefore, conventionally, in order to obtain a good releasing property of the fixing roller, a releasing layer is provided on the roller surface and silicone oil is supplied to the fixing roller surface. Various proposals have been made as a device for supplying the silicone oil, and a device that uses a supply roller having a porous surface layer filled with oil is already known.

A fixing device using such a supply roller can supply oil thinly and evenly to the fixing roller, obtain good releasability, and excessive oil supply causes oil stains on the transfer paper. It is extremely advantageous that there are few occurrences.

However, even if the releasing property of the fixing roller is improved, the offset cannot be completely eliminated, and it is inevitable that a slight amount of offset remains on the fixing roller. For this reason, even in a fixing device using a porous supply roller, the surface of the supply roller is contaminated with toner or paper dust, and the oil supply amount of the supply roller is reduced over time, and the contamination of the supply roller is deteriorated. The problem of soiling the transfer paper occurs by re-transferring to.

Although it has not been publicly known that the above problems can be alleviated, the applicant of the present application has proposed the following fixing device using a supply roller having a porous surface layer which is of the same quality as the release layer of the fixing roller. ing. In this apparatus, since the release layer of the fixing roller and the porous surface layer of the supply roller are of the same quality, it is difficult for the toner adhering to the fixing roller to be transferred to the supply roller, and the load on the supply roller for contamination is reduced.

[0006]

By the way, when the fixing roller is viewed in the axial direction, the fixing roller and the pressure roller such as the temperature distribution, the size of the transfer material, the paper dust coming from the roughness of the surface of the transfer material at the time of paper feeding, etc. It was clarified by experiments that the offset amount of toner and the like varies depending on the difference in the nip distribution of.
However, in the fixing device described above, no mention is made of a change in the degree of contamination in the axial direction of the fixing roller, and no countermeasure has been taken.

In view of the above-mentioned problems, the present invention can prevent the supply member from becoming dirty, and can cope with the change in the degree of dirt in the axial direction of the fixing roller to suppress the variation in the degree of dirt attached to the supply member. An object of the present invention is to provide a fixing device that can be used.

[0008]

In order to achieve this object, the present invention is directed to a fixing roller having a release layer on its peripheral surface, a pressure rotating member abutting against the fixing roller, and an axis line of the fixing roller. A transfer member that is abutted along the direction and supplies oil over almost the entire effective fixing width of the fixing roller, and transfers the transfer material carrying the unfixed toner image to the fixing roller and the pressure rotator. In a fixing device for fixing an unfixed toner image on a transfer material by heating and pressing by nipping and transporting the supply member, the supply member has a porous surface layer that is the same quality as the release layer of the fixing roller, and It is characterized in that an oil supply amount changing means for changing the oil supply amount in the axial direction of the fixing roller is provided.

Further, in order to achieve the above object, in the present invention, the supply member has the same porous surface layer as the releasing layer of the fixing roller, an oil holding layer for holding oil, and the oil holding layer for the oil holding layer. An oil supply amount changing means for changing the oil supply amount in the axial direction of the fixing roller is provided with an adhesive layer for adhering the surface layer, and the oil supply amount changing means changes the application area of the adhesive of the adhesive layer. It is characterized by

Further, in order to achieve the above object, the present invention provides that the adhesive of the adhesive layer is arranged in a pattern.
It is characterized in that the oil supply amount changing means changes the size of the adhesive pattern.

Further, in order to achieve the above object, the adhesive of the adhesive layer is arranged in a pattern, and the oil supply amount changing means changes the interval of the pattern of the adhesive.

[0012]

According to the above construction, the supply member has the same porous surface layer as the release layer of the fixing roller, and the oil supply amount changing means for changing the oil supply amount in the axial direction of the fixing roller. Therefore, the load of dirt on the supply member is reduced, and even if the quantity of dirt varies in the axial direction of the fixing roller, the oil supply amount changing means changes the oil supply quantity according to the dirt to remove all the dirt attached to the supply member. Can be reduced by.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a side view showing a fixing device according to the present invention. In FIG. 1, a pressure roller 3 as a pressure rotator is brought into pressure contact with a fixing roller 1 having a heater 2 built therein, and both the fixing roller 1 and the pressure roller 3 are rotatable via bearings (not shown). The fixing roller 1 is further connected to driving means (not shown) such as a gear. In this fixing roller 1, the journal portion is made of aluminum and the surface layer is treated with a fluororesin as the release layer 1a. This fluororesin processing is PFA, PTFE or the like. In the fixing device shown in FIG.
Is an inlet guide, 11 is a thermistor, 12 is a separation claw whose tip is brought into contact with the fixing roller 1 by a separation claw spring 13, 14 is a vertical paper discharge guide, and 15 is a paper discharge roller.

A supply roller 4 as an oil supply member is brought into contact with the fixing roller 1 over substantially the entire effective fixing area through which the transfer material 9 of the maximum size passes. It is driven to rotate by the rotation of 1. As shown in FIG. 2, the supply roller 4 has a roller base body 5 as an oil holding layer made of foam, and a fluorine resin of the same quality as the release layer of the fixing roller 1, for example, PTFE, in which numerous minute holes are formed. And a bonding layer 7 for bonding the surface layer 6 to the roller base body 5. The roller base body 5 is filled with silicone oil. When the fixing roller 1 rotates, the supply roller 5 rotates the roller base body 5.
The silicone oil filled in is exuded from the minute holes of the surface layer 6 and supplies a minute and uniform oil to the surface of the fixing roller 1.

In the thus constructed fixing device, when the transfer material 9 carrying a toner image is fed and is conveyed while being sandwiched between the fixing roller 1 and the pressure roller 3, the toner is melted by heat and transferred. It is fixed at 9. At this time, since the fixing roller 1 is provided with the release layer 1a and a slight amount of silicone oil is applied as described above, the offset is considerably reduced. However, it is impossible to completely eliminate the offset, and it is inevitable that a slight amount of dirt is transferred to the fixing roller 1. This dirt tends to transfer from the fixing roller 1 to the supply roller 4, but the surface layer 9 of the supply roller 4
Is of the same quality as the release layer 1a of the fixing roller 1, the cleaning effect of the supply roller 4 is weakened, and the load on the supply roller 4 for contamination is reduced.

As described above, the supply roller 4 is hard to be contaminated with dirt, but it is impossible to prevent the dirt from being adhered at all, and a very small amount of dirt is adhered to the supply roller 4. Is inevitable. Further, when the fixing roller 1 is viewed in the longitudinal direction, that is, the axial direction, the temperature distribution varies, the size of the paper to be passed, the paper dust and the like coming from the roughness of the surface of the transfer material at the time of feeding, and the pressure applied to the fixing roller 1. Since the toner offset amount differs due to the difference in the nip distribution of the roller 3, the way of contamination also differs in the axial direction. Here, when the relationship between the amount of adhered dirt on the supply roller 4 and the amount of oil supply is examined and seen, as shown in the graph of FIG. 4, the amount of adhered dirt can be reduced if the amount of oil supply is increased.

In order to reduce the amount of adhered dirt, it is conceivable to increase the oil supply amount over the entire oil supply region. However, if the oil supply amount is increased in the oil supply region, not only the useless oil is supplied to a portion with little contamination even if the supply amount is very small, but also the supply roller 4 is prematurely depleted of oil and other members are used. It will reach the end of its service life earlier than. Therefore, in order to secure the service life of the supply roller 4 to some extent, it becomes necessary to fill and hold a large amount of oil in the roller.
Will have to be upsized.

Therefore, in the present invention, the supply roller 4 is provided with oil supply amount changing means for changing the oil supply amount in the axial direction of the fixing roller 1. As the oil supply amount changing means of this embodiment, the opening ratio of the fine holes in the surface layer 6 of the supply roller 4 is changed to change the oil supply amount in the axial direction of the fixing roller 1. In this case, since it is technically difficult to change the aperture ratio of the fine holes themselves in the surface layer 6, the aperture ratio is changed by the adhesive layer 7 for bonding the surface layer 6 to the roller base 5. As shown in FIG. 6, a conventional adhesive layer 7 is formed by applying an adhesive pattern 8 forming the adhesive layer 7 to the roller base 5 at a constant size and at regular intervals, and then adhering the surface layer 6 thereto. There is. In this case, since the adhesive does not pass oil, the oil of the supply roller 4 exudes from the portion without the adhesive pattern 8 and is supplied to the fixing roller 1.
Oil is evenly applied over the entire area.

Therefore, in this embodiment, as shown in the graph of FIG. 5, since the oil supply amount is proportional to the opening ratio of the surface layer 6, the adhesive pattern 8 at the portion where the oil supply amount is desired to be increased is set small. There is. Generally, the areas corresponding to both ends of the fixing roller 1 have variations in temperature distribution, the size of paper to be passed, paper dust and the like due to the roughness of the surface of the transfer material at the time of feeding, the fixing roller 1 and the pressure roller 3. Due to the difference in the nip distribution, the area becomes a place where dirt easily adheres, so the adhesive pattern 8 is made small in order to increase the oil supply amount to the area. Since it is not necessary to increase the oil supply amount in the central region where the offset is small, the adhesive pattern 8 having a size substantially the same as the conventional one is formed, and the surface layer 6 is adhered by the adhesive layer 7.

With this structure, the toner on the fixing roller 1
Since the oil supply amount can be increased only in the region where dirt such as paper dust is easily attached, it is possible to prevent the dirt attached from the fixing roller 1 to the supply roller 4 from being partially distributed. It is also an advantageous mode to provide a cleaning roller (not shown) to the surface of the supply roller 4 to clean the surface layer 6 as needed, but at this time, the dirt attached to the supply roller 4 is partially biased. It is also possible to prevent the problem that only a part of the cleaning roller becomes thick. The adhesive pattern 8 is formed by applying an adhesive through a film material in which the pattern shape is cut out in advance, and it is easy to change the size of the pattern.

Although the oil supply amount changing means changes the size of the adhesive pattern 8 to change the opening ratio of the surface layer 6 in the above embodiment, the opening ratio changes the interval between the adhesive patterns 8 having the same shape. The oil supply amount changing means may be configured to change the interval between the adhesive patterns 8 having the same shape. Further, the oil supply amount changing means may be configured to change both the size and the interval of the adhesive pattern 8 to change the aperture ratio.

The means for changing the amount of oil supply according to the present invention is not limited to changing the opening ratio of the surface layer 6 from the size and spacing of the adhesive pattern 8, and for example, the oil filled in the roll base 5 has a different viscosity. It is also possible to prepare a plurality of components and to fill the portion corresponding to the portion where it is desired to increase the supply amount with oil of low viscosity, and to fill the other portion with oil of high viscosity.

By the way, the location where the toner or paper dust is likely to adhere to the fixing roller 1 differs depending on the model such as whether the transfer material is transported based on the center or one side. It may be appropriately determined for each model.
Further, since the location where toner or paper powder is likely to adhere to the fixing roller 1 varies depending on the usage environment such as the size of the transfer material that is frequently used, the location where the oil supply amount is increased may be determined according to the user's use. Good. In this case, the fixing roller 1
Since the areas where toner and paper dust are likely to adhere are patterned in a few cases, it is possible to deal with each user by preparing a supply roller according to the pattern in advance.

[0025]

According to the first aspect of the invention, since the supply member is provided with the porous surface layer which is the same quality as the release layer of the fixing roller, the dirt adhering to the supply member can be reduced and the fixing roller of the fixing roller can be reduced. Even if the amount of dirt varies in the axial direction, the oil supply amount changing means can change the amount of oil supply according to the amount of dirt to reduce the amount of dirt attached to the supply member in the entire region. Further, since the portion where the oil supply amount is increased is a part that is heavily contaminated, the service life of the supply member due to oil exhaustion is not significantly affected.

According to the second aspect of the invention, since the oil supply amount is changed by changing the adhesive application area of the adhesive layer for adhering the surface layer to the oil holding layer, it is easy to control the oil amount to be supplied. In addition, it is possible to set the increase / decrease portion of the supplied oil amount with high accuracy. According to the configurations of claims 3 and 4, the application area of the adhesive of the adhesive layer can be changed very easily.

[Brief description of drawings]

FIG. 1 is a side view showing a fixing device according to the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view of the supply roller of FIG.

FIG. 3 is an explanatory diagram showing an adhesive pattern of a supply roller of the present invention.

FIG. 4 is a graph showing a relationship between an oil supply amount and a dirt adhesion amount.

FIG. 5 is a graph showing a relationship between an oil supply amount and an opening ratio.

FIG. 3 is an explanatory diagram showing an adhesive pattern of a conventional supply roller.

[Explanation of symbols]

 1 Fixing Roller 3 Pressure Roller 4 Supply Roller 5 Roller Base 6 Surface Layer 7 Adhesive Layer 8 Adhesive Pattern 9 Transfer Material

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[Procedure amendment]

[Submission date] June 23, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a side view showing a fixing device according to the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view of the supply roller of FIG.

FIG. 3 is an explanatory diagram showing an adhesive pattern of a supply roller of the present invention.

FIG. 4 is a graph showing a relationship between an oil supply amount and a dirt adhesion amount.

FIG. 5 is a graph showing a relationship between an oil supply amount and an opening ratio.

FIG. 6 is an explanatory diagram showing an adhesive pattern of a conventional supply roller.

[Explanation of reference numerals] 1 fixing roller 3 pressure roller 4 supply roller 5 roller base 6 surface layer 7 adhesive layer 8 adhesive pattern 9 transfer material

Claims (4)

[Claims] 1. A fixing roller having a release layer on its peripheral surface, a pressure rotator abutting against the fixing roller, and an abutting member in contact with the fixing roller along the axial direction of the fixing roller, and having a fixing effective width of the fixing roller. It has a supply member that supplies oil over almost the entire width,
A fixing device for fixing an unfixed toner image on a transfer material by heating and pressing the transfer material carrying an unfixed toner image between the fixing roller and the pressure rotating body to fix the unfixed toner image on the transfer material. A fixing device comprising a porous surface layer which is the same in quality as the release layer of the fixing roller and which is provided with an oil supply amount changing means for changing the oil supply amount in the axial direction of the fixing roller. 2. A fixing roller having a release layer on its peripheral surface, a pressure rotating body contacting the fixing roller, and an abutting member in contact with the fixing roller along the axial direction of the fixing roller to obtain a fixing effective width of the fixing roller. It has a supply member that supplies oil over almost the entire width,
A fixing device for fixing an unfixed toner image on a transfer material by heating and pressing the transfer material carrying an unfixed toner image between the fixing roller and the pressure rotating body to fix the unfixed toner image on the transfer material. A surface layer that is the same as the release layer of the fixing roller and is porous, an oil holding layer that holds oil, and an adhesive layer that bonds the surface layer to the oil holding layer,
A fixing device comprising: an oil supply amount changing means for changing an oil supply amount in an axial direction of the fixing roller, wherein the oil supply amount changing means changes an application area of the adhesive of the adhesive layer. 3. The fixing device according to claim 2, wherein the adhesive of the adhesive layer is arranged in a pattern, and the oil supply amount changing means changes the size of the pattern of the adhesive. And fixing device. 4. The fixing device according to claim 2, wherein the adhesive of the adhesive layer is arranged in a pattern, and the oil supply amount changing means changes an interval of the pattern of the adhesive. Fixing device.