JP3594732B2 - Fixing device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing device.
[0002]
[Prior art]
A typical conventional fixing device has the same configuration as that of the embodiment of the present invention shown in FIG. 1 and will be described with reference to this configuration. It comprises a fixing roller 1, a pressure roller 2 provided opposite to the fixing roller 1, and an application roller 3 for applying a release agent to the fixing roller 1 while rotating along with the fixing roller 1. Reference numeral 4 denotes a heater, reference numeral 5 denotes a sheet, and reference numeral 6 denotes a toner image carried thereon, and the application roller 3 may apply a release agent to the pressure roller 2 instead of the fixing roller 1 in some cases. .
[0003]
In such a device, in the early stage of use, for example, the amount of the release agent applied per prescribed unit per sheet of paper 5 is sufficient. In addition, there is a problem in that dirt such as toner and dust adheres from the fixing roller 1 or the pressure roller 2 to reduce the application capability of the release agent, and the application amount of the release agent decreases. On the other hand, as the fixing roller 1 or the pressure roller 2 is used over time, the releasability is reduced due to the attachment of dirt such as dust, and there is a problem that a larger amount of the release agent is required as compared with the initial stage. .
[0004]
Therefore, in order to solve such a problem, there have been proposed those disclosed in (1) Japanese Patent Application Laid-Open No. 5-94109 and (2) Japanese Utility Model Application Laid-Open No. 1-139266. In these, the same parts as those of the conventional one are denoted by the same reference numerals, and description thereof will be omitted, and different parts will be mainly described.
[0005]
The fixing device shown in (1) has a main part as shown in FIG. 19, in which first and second application rollers 3-1 and 2 are provided as application rollers. Only the first application roller 3-1 is brought into contact with the fixing roller 1 to constantly supply the release agent to the fixing roller 1, and when the total number of copies reaches 4,000 with use over time, the second application roller 3-2 is brought into contact with the fixing roller 1 to supply a release agent to the fixing roller 1. The main part of the fixing device shown in (2) is as shown in FIG. 20, and the cleaning roller 20 comes into contact with the application roller 3 to clean dirt attached to the application roller 3. It has become.
[0006]
[Problems to be solved by the invention]
By the way, such a fixing device has a complicated structure, requires many parts, and is not only expensive and expensive, but also difficult to maintain. However, it is not possible to effectively prevent the adhesion of dirt such as dust in the above, and it is not possible to solve the problem that a large amount of release agent is required.
[0007]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the conventional fixing device as described above, and to effectively prevent adhesion of dirt such as dust to a fixing roller or a pressure roller when used over time. The mold performance can be prevented from deteriorating, the number of parts is small, the structure is simple, the cost is low and inexpensive, and maintenance is easy. An object of the present invention is to provide a fixing device that does not require an agent.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is directed to a fixing device, wherein the application roller according to the first aspect of the invention has a regulating layer on an outer periphery thereof for regulating an application amount of a release agent. The regulating layer has a different regulating ability in the thickness direction, so that it gradually falls off the surface due to abrasion caused by contact with the fixing roller or the pressure roller due to use over time, so that the coating amount of the release agent per specified unit is increased. It is characterized by having become.
[0009]
According to a second aspect of the present invention, in the first aspect, the regulating layer is made of a porous film, and the thickness of the regulating layer is reduced to increase the permeability of the release agent to increase the coating amount. The invention according to claim 3 is characterized in that, in claim 2, the regulation layer is made of at least two or more porous films, and the total area of the pores of the porous film is increased toward the inner layer, It is characterized in that the permeability of the release agent is good .
[0010]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the abrasion of the regulating layer is caused by slip between the fixing roller and the pressure roller with which the regulating layer contacts. According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the abrasion resistance of the regulating layer is inferior to the abrasion resistance of the surface layer of the fixing roller or the pressure roller with which the regulating layer contacts. It is a feature .
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. In each embodiment, the same parts as those described in the conventional example are denoted by the same reference numerals, and description thereof will be omitted. Different parts will be mainly described.
[0012]
FIGS. 2 and 3 show the application roller 3 of the present invention, in which reference numeral 7 denotes a support shaft, 8 denotes a holding layer for holding the coating agent, and 9 denotes a coating layer for coating the outer periphery thereof.
[0013]
4 to 9 show a coating roller 3 according to a first embodiment of the present invention. In such a first embodiment, the regulating layer 9 of the coating roller 3 is made of a heat-resistant material such as a nonwoven fabric or felt. Of the fiber member 10. Depending on the number of the gaps 13 between the fibers 12 of the fiber member 10 or the size of the total area, etc., the permeability of the coating agent, that is, the amount of permeation differs, and the number of the gaps 13 between the fibers 12 increases or the total area increases As the transmission becomes larger, the transmission amount increases. The same applies to the thickness of the fiber member 10, and the thin fiber member 10-1 shown in FIG. 4 has a larger transmission amount than the thick fiber member 10-2 shown in FIG.
[0014]
The permeation amount of the coating agent depending on the thickness of the regulation layer 9 changes with time, and this will be described with reference to FIGS. FIG. 6 shows a state of the application roller 3 at an early stage of use, FIG. 7 is an enlarged view of a portion surrounded by a line 7 in FIG. 6, FIG. 8 shows a state of the application roller 3 after use over time, and FIG. Is an enlarged view of a portion surrounded by a line 9 in FIG. The thickness of the fiber member 10 in the initial stage of use is thick as shown by T in FIG. 6, but after use over time due to the application of pressure during use, the gap 13 is formed in the radial direction as shown in FIG. As a result, the thickness of the fiber member 10 becomes thinner as indicated by t in FIG.
[0015]
FIGS. 10 to 16 show a coating roller 3 according to a second embodiment of the present invention. In such a second embodiment, the regulating layer 9 of the coating roller 3 is made of a porous resin such as a fluororesin. It is constituted by a film 11. Depending on the number or total area of the through holes 14 of the porous film 11, the permeability of the coating agent, that is, the amount of transmission differs, and the amount of transmission increases as the number of through holes 14 or the total area increases. More. This is the same depending on the thickness of the porous film 11. The thin porous film 11-1 shown in FIG. 10 has a higher transmission amount than the thick porous film 11-2 shown in FIG. More.
[0016]
Next, a structure in which the regulating layer 9 is constituted by a multilayer (three in this embodiment) porous films 11-1, 2, 3 will be described with reference to FIGS. FIG. 12 shows the state of the regulating layer 9 at the initial stage of use, FIG. 13 shows the state after the first use, and FIG. 14 shows the state after the second use after further use. After the primary aging, the outermost porous film 11-3 is worn out by the pressure applied during use and falls off. After the secondary aging, the outermost porous film 11-3 is further used. The film 11-2 is worn and dropped by the pressure applied during use, and the film is applied by the initial innermost porous film 11-1. In this way, the regulating layer 9 becomes thinner sequentially with the lapse of time, and accordingly the coating layer, which initially had a relatively small amount of coating material permeated therein, gradually changes from the primary aging to the secondary aging. Will increase. In this case, the abrasion resistance of the regulating layer 9 is inferior to the abrasion resistance of the surface layer of the fixing roller 1 or the pressing roller 2 with which it comes into contact.
[0017]
In this case, as shown in FIG. 15, the number of through holes 14 in each layer is sequentially increased from the outer layer to the inner layer, and in the case of a single layer as shown in FIG. 16, the size of the through holes 14 is increased from the outer layer to the inner layer. , The total area of the through holes 14 is increased, thereby making it possible to further increase the rate of increase in the amount of the coating material permeated.
[0018]
FIG. 17 shows a third embodiment of the present invention. In this embodiment, a rotation suppressing member comprising a friction cylinder 15 is mounted between a support shaft 7 of the application roller 3 and a bearing (not shown) thereof. Then, a slip is generated between the application roller 3 and the fixing roller 1, and the friction causes the control layer 9 of the application roller 3 to be worn out and fall off, so that the above-described state is obtained.
[0019]
FIG. 18 shows a fourth embodiment of the present invention. In this embodiment, a friction plate 16 that comes into contact with the outer periphery of the application roller 3 is used as a rotation suppressing member of the application roller 3. Only the configuration is different, and the other configuration is the same, so that the description is omitted.
[0020]
【The invention's effect】
The present invention is as described above, and a fixing device including a fixing roller, a pressing roller provided opposite to the fixing roller, and an application roller for applying a release agent to the fixing roller or the pressing roller. In the invention according to claim 1, the application roller has a regulation layer on an outer periphery thereof for regulating an application amount of a release agent, and the regulation layer has a regulation ability different in a thickness direction thereof, and the regulation layer is used over time. The invention according to claim 2 is characterized in that the toner is sequentially dropped from the surface due to abrasion caused by contact with the fixing roller or the pressure roller, and the amount of the release agent applied per specified unit is increased . The regulating layer is formed of a porous film, and the thickness of the regulating layer is reduced to increase the permeability of the release agent to increase the coating amount . Regulation is small Both consist of two or more layers of porous film, wider the total area of the porous film of the hole as made in the inner layer, the permeability of the release agent has a good, the invention described in claim 4 According to any one of claims 1 to 3, the abrasion of the regulating layer is caused by slip between the fixing roller and the pressure roller with which the regulating layer comes into contact. There is an effect that the adhesion of dirt such as is effectively prevented, and that the releasing performance is not deteriorated and the fixing property such as offset is not deteriorated. Moreover, there is an effect that the structure is simple, the cost is low, the cost is low, and the maintenance is easy .
[0021]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the abrasion resistance of the regulating layer is inferior to the abrasion resistance of the surface layer of the fixing roller or the pressure roller with which the regulating layer contacts. Therefore, the surface layer of these rollers is prevented from being worn by the surface layer of the application roller, and there is an effect that a large amount of release agent is not required when used over time.
[Brief description of the drawings]
FIG. 1 is a front view of a main part according to first and second embodiments of the present invention.
FIG. 2 is a vertical cross-sectional front view of the application roller.
FIG. 3 is a vertical sectional side view of the same.
FIG. 4 is an operation explanatory view of the application roller having a thin regulating layer according to the first embodiment.
FIG. 5 is an explanatory diagram of an operation of an application roller having the same thick regulation layer.
FIG. 6 is a vertical sectional side view of the initial state of the application roller.
FIG. 7 is an enlarged view of a portion surrounded by a line 7 in FIG.
FIG. 8 is a vertical sectional side view of the application roller after use over time.
FIG. 9 is an enlarged view of a portion surrounded by a line 9 in FIG.
FIG. 10 is an operation explanatory view of an application roller having a thin regulating layer according to a second embodiment of the present invention.
FIG. 11 is an operation explanatory view of the application roller having the thick regulation layer.
FIG. 12 is an explanatory diagram of an initial operation of the application roller.
FIG. 13 is an explanatory diagram of the operation after the first time use.
FIG. 14 is an explanatory view of the operation after the second time use.
FIG. 15 is a partial cross-sectional view of a regulation layer of another application roller of the second embodiment.
FIG. 16 is a partial cross-sectional view of a regulation layer of a coating roller according to still another embodiment.
FIG. 17 is an operation explanatory view of the third embodiment of the present invention.
FIG. 18 is an operation explanatory view of the fourth embodiment.
FIG. 19 is a view similar to FIG. 1 of a conventional fixing device of the same type as the present invention.
FIG. 20 is a drawing similar to FIG. 1 of another conventional fixing device of the same type as the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixing roller 2 Pressure roller 3 Application roller 4 Heater 5 Paper 6 Toner image 7 Support shaft 8 Holding layer 9 Restriction layer 10 Fiber member 11 Porous film 12 Fiber 13 Gap 14 Through hole 15 Friction cylinder 16 Friction plate

Claims (5)

In a fixing device including a fixing roller, a pressure roller provided to face the fixing roller, and an application roller that applies a release agent to the fixing roller or the pressure roller,
The coating roller has a regulation layer on its outer periphery that regulates the amount of the release agent applied, and the regulation layer has a different regulation ability in its thickness direction, and is caused by contact with a fixing roller or a pressure roller over time. A fixing device characterized in that the fixing agent is sequentially dropped from the surface due to abrasion to increase the application amount of a release agent per specified unit . The fixing device according to claim 1, wherein the regulating layer is formed of a porous film, and the thickness of the regulating layer is reduced to increase the permeability of the release agent to increase the coating amount . The regulating layer is composed of at least two or more porous films, and the inner layer is characterized in that the total area of the pores of the porous film is widened and the permeability of the release agent is good. The fixing device according to claim 2. 4. The fixing device according to claim 1, wherein the abrasion of the regulating layer is caused by slippage between the regulating layer and a fixing roller or a pressure roller that contacts the regulating layer . 5. The fixing device according to claim 1, wherein the abrasion resistance of the regulating layer is lower than the abrasion resistance of the surface layer of the fixing roller or the pressure roller with which the regulating layer contacts .

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