JP3450604B2 - Fixing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device used in an image forming apparatus such as an electrophotographic copying apparatus and an electrostatic recording apparatus. More specifically, it has a fixing roller for fixing an unfixed toner image formed on a recording material such as transfer paper, electrostatic recording paper, electrofax paper (hereinafter referred to as transfer material) as a permanent image. The present invention relates to a fixing device that applies a release agent such as silicon oil to a fixing roller in order to prevent offset of the toner to the fixing roller.

[0002]

2. Description of the Related Art Conventionally, as a fixing device for applying a releasing agent (hereinafter referred to as oil) such as silicone oil to a fixing roller, a fixing device for applying oil to the fixing roller by a felt or a pump for drawing up oil by a felt and applying a roller There have been proposed a device for applying to a fixing roller through a device, a device for pumping silicon oil using a pumping roller, and the like.

Conventionally, the surplus of the releasing agent such as silicon oil applied on the pressure roller is formed on the surface of the pressure roller by an oil removing blade means (hereinafter referred to as a removing blade) made of silicon rubber or the like. The portions are removed by contacting them with constant pressure.

Residual toner such as toner and paper dust on the surface of the pressure roller is cleaned by the cleaning means in contact with the surface of the pressure roller. Usually, a cleaning web having a web shape is used as the cleaning means. This is due to offset of the recording material image when passing through the fixing / pressurizing roller, roller stains due to toner, stains such as paper dust, or image deterioration due to roller stains at abnormal times such as paper jams, fixing / pressurizing rollers. In order to prevent scratches and the like, a web that is usually long is brought into contact with the surface of the fixing and pressure roller at a predetermined pressure, and at a predetermined interval,
Alternatively, the surface of the fixing / pressurizing roller is constantly wiped and cleaned by a new web surface by feeding out a predetermined amount at predetermined time intervals.

FIG. 9 of the accompanying drawings shows a fixing device for pumping silicon oil using a pump roller. In the apparatus of FIG. 9, P is an oil pan which is a release agent storage means such as silicon oil O, and a part of the first scooping roller 1 is immersed in the oil in the oil pan P.
The scooping roller 2 is in contact with the first scooping roller 1 or is rotating with a gap. The first and second scooping rollers 1 and 2 are rotationally driven by a driving source (not shown). Further, the application roller 3 which is rotationally driven by a drive source (not shown) rotates in contact with the second drawing roller 2, and the application roller 3 is fixed by the fixing roller 4.
The surface of the fixing roller 4 is coated with oil that can be moved in and out of the fixing roller 4 or is constantly contacted with the oil.
Reference numeral 5 denotes a pressure roller that rotates in pressure contact with the fixing roller 4,
The transfer material is pressure-fed at the nip portion between the rollers 4 and 5 to fix the transfer material. Further, the coating roller 3 is in contact with a metering blade 9 made of an elastic body such as fluorine rubber urged by a spring 10 so that a constant pressure is always maintained against the coating roller. The amount of oil above 3 is regulated to a predetermined value. The oil O applied on the fixing roller 4 is also applied on the surface of the pressure roller at the nip portion.

Reference numeral 31 denotes a pressure roller cleaning web as a pressure roller cleaning means, which is brought into contact with the surface of the pressure roller by a constant pressure and is delivered at a predetermined interval or a predetermined time by a predetermined amount. By doing so, the surface of the pressure roller is wiped and cleaned.

Reference numeral 32 denotes an oil removing blade as a means for wiping the release agent on the surface of the pressure roller, which is applied on the fixing roller 4 by the oil applying means and further applied on the pressure roller 5.
Of the oil applied to the surface, the excess oil O
Is to be removed.

[0008]

However, the above-mentioned conventional example has the following drawbacks. That is, when a rubber blade made of silicon rubber or the like such as the oil removing blade is brought into contact with a high temperature member such as a fixing roller or a pressure roller, the contact portion of the blade is deformed by the high temperature, The problem is that a constant contact edge cannot be obtained. It is known that this problem occurs due to the following reasons.

Generally, a rubber blade such as an oil removing blade is formed on a supporting member made of iron, stainless steel, copper-based metal, aluminum or the like by a method such as integral molding, adhesion or fusion. On the other hand, the blade itself is made of fluororubber, silicone rubber or the like. The blade rubber and the support member are integrated by these methods.

Further, the blade integrated by these methods is usually fixed and supported by a blade fixing member made of iron or the like in the apparatus. In other words, the blade supporting member and the blade fixing member are fastened with a fixing member such as a screw to bring the roller surface into contact with the roller surface with a constant pressure, and the positioning is performed with high accuracy.

However, the above conventional example has the following problems. That is, as in the above configuration, in the blade, since the blade supporting member and the blade fixing member were fastened by a fixing member such as a screw,
By contacting the roller surface at high temperature, the difference in thermal expansion between the blade support member and the blade fixing member causes distortion, and as a result, proper contact between the blade edge and the roller cannot be achieved. However, the oil has slipped through and hits on one side, making it impossible to remove the oil, which is the original purpose.

[0012] These phenomena are particularly remarkable when the materials of the blade supporting member and the blade fixing member are different, and in some cases, the ridgeline of the blade tip portion becomes a wavy phenomenon in the longitudinal direction, It causes a remarkable blade contact failure. Further, even if the blade support member and the blade fixing member are the same material, due to the heat cycle from high temperature to low temperature, the blade itself causes permanent strain, and as a result, stress strain particularly concentrates on the fastening portion due to screws, As a result, the same blade contact failure as described above occurs, image deterioration, oil scraping failure, and the like occur, resulting in problems such as a drastic decrease in blade durability.

The present invention solves the above problem, and in a configuration in which the blade is brought into contact with a roller having a high temperature such as a fixing roller, a pressure roller, and an oil applying roller, heat generated between the blade, the blade supporting member, and the blade fixing member By adopting a blade fixing method that prevents static deformation and distortion, it is possible to prevent the defect that distortion occurs due to the difference in thermal expansion between the blade supporting member and the blade fixing member, and it is appropriate between the blade edge and the roller. Poor contact,
It is an object of the present invention to provide a fixing device that prevents the drawbacks such as oil slipping off and uneven contact, which makes it impossible to remove the oil, which is the original purpose.

[0014]

Therefore, in the present invention, a fixing roller for fixing an unfixed image on a recording material, and a pressure roller for pressing the fixing roller to form a nip for nipping and conveying the recording material. , A release agent applying means for applying a release agent to the surfaces of the fixing roller and the pressure roller, and a breaker for wiping the release agent
And a blade means for wiping the release agent onto the blade means.
Blade member and blade support supporting this blade member
A holder and a support pressing member for pressing the blade support are provided.
In the existing fixing device, the support pressing member
The total pressure P on the blade support is determined by the blade member contacting the target.
The contact pressure is larger than the contact pressure, and the blade support
From the support pressing member that can slide with the pressure member to the blade
It is less than the maximum total pressure on the support which solves the above problems.

[0015]

DETAILED DESCRIPTION OF THE INVENTION

(Embodiment 1) An embodiment of an image forming apparatus to which the present invention is applied will be described below with reference to the drawings. This embodiment will be described using a full-color copying machine.

In the embodiment shown in FIG. 1, the present invention is embodied in an electrophotographic copying machine. In this embodiment, 1a to 1d are electrophotographic photosensitive drums as image forming media. Around the photosensitive drums 1a to 1d, primary chargers 2a to 2d, exposure means 3 such as a laser beam exposure device, and image forming means such as developing devices 4a to 4d are provided. Since the construction and operation of these image forming means are well known to those skilled in the art, further description will be omitted.

The image formed on the photosensitive drum 1 is transferred onto the transfer material P fed from the paper feeding device 5 and transferred to the discharge devices 6a to 6a.
It is transcribed under the action of 6d. The transfer material P that has completed the transfer is conveyed to the fixing device 9 by the endless belt 8 of the transfer material conveying device 7, and the transferred image is fixed on the transfer material. At this time, the conveyance speed of the endless belt 8 is set to the fixing roller pair 10, 1 of the fixing device.
The transfer speed is slightly higher than the transport speed of 1, and the transfer material P forms a loop to prevent the occurrence of wrinkles during fixing. Further, the conveying speed of the endless belt 8 is usually set to match the peripheral speed of the photoconductor drum 1 to prevent the expansion and contraction of the image when the image is transferred onto the transfer material. The residual developer is removed from the photosensitive drum 1 after the transfer by the cleaners 12a to 12d, and the next image forming process is performed.

In the apparatus of FIG. 2, a fixing heater 13 composed of a halogen lamp or the like is arranged inside both the fixing roller 10 and the pressure roller 11, and the transfer material is pressed at the nip portion of both rollers 10, 11. Transport and heat fix. 22
Is an oil pan which is a release agent storage means such as silicone oil O.
15 is arranged, and further, the coating roller 16 rotates in contact with the fixing roller 10 so that the coating roller 16 can freely come into contact with or separate from the fixing roller 10 or constantly come into contact with the fixing roller 10 to apply the pumped oil to the surface of the fixing roller 10. ing. Further, the coating roller 16 is in contact with a metering blade 18 made of an elastic material such as fluorine rubber urged by a spring 17 so that a constant pressure is always maintained against the coating roller. The amount of oil on 16 is regulated to a predetermined value. Reference numeral 19 is a fixing roller thermistor as a fixing roller surface temperature detecting means for detecting the surface temperature of the fixing roller 10, and 20 is a pressure roller thermistor as a pressure roller surface temperature detecting means for detecting the surface temperature of the pressure roller 11. is there. The fixing roller thermistor 19 and the pressure roller thermistor 20 are provided with a leaf spring 21 as an urging means.
Each is configured to come into contact with the roller surface by a desired contact pressure. These thermistors 1
9 and 20, the surface temperatures of the fixing roller and the pressure roller are independently temperature-controlled by a fixing temperature adjusting circuit (not shown) so as to reach desired control temperatures T _U and T _L. 23 is
The fixing roller separating claw is a separating claw as a separating device for separating the recording paper after passing through the fixing roller from the roller surface. Several separation claws 23 are arranged in the thrust direction (width direction) of the pressure roller 11 and correspond to the size of the recording paper used in the width direction. Denoted at 25 and 26 are a paper ejection upper guide and a paper ejection lower guide for guiding the recording paper after passing through the fixing roller to the paper ejection means. 24a and 24b are a pair of discharge rollers for discharging. Reference numeral 41 denotes a fixing roller cleaning web made of non-woven fabric or the like for cleaning the surface of the fixing roller 10 which is a fixing roller cleaning means. The cleaning web 41 is driven by a cleaning web drive means (not shown) so that the surface of the fixing roller can be constantly cleaned with a new web surface.

Reference numeral 51 denotes oil O on the surface of the pressure roller 11.
It is an oil removing blade (blade means) made of an elastic body such as fluorine rubber for wiping away the oil. 33 is a blade base for supporting the oil removing blade 51,
It is rotatably attached to the frame 39 about the rotation center 33b. The oil removing blade 51 is biased by the spring 34 so that a constant pressure is always maintained against the surface of the pressure roller 11. This regulates the amount of oil on the pressure roller to a predetermined amount.

FIG. 3 shows a detailed view of the oil removing blade 51. 52 is a blade made of fluororubber, 53
Is a blade support plate, and in the present embodiment,
The material is a phosphor bronze plate. A blade pressing member 54 is a member for fixing the blade to the blade base 33 with a uniform pressure. Reference numeral 55 is a step screw for pressing and fixing the blade. A blade pressing leaf spring (elastic member) 56 is integrated with the blade pressing member 54 by spot welding or burring caulking in the present embodiment. FIG. 4 shows a plan view and a sectional view of the blade. The blade 51 is fixed to the blade base 33 with a step screw 55 via a blade pressing member 54. A blade pressing leaf spring 56 is provided at a position corresponding to each stage screw fixing portion (four positions in this embodiment) of the blade pressing member 54. In this figure, the two-dot chain line of the leaf spring 56 is the shape before the step screw is tightened. By tightening the step screw 55,
The leaf spring 56 has a shape represented by a solid line,
That is, a force for pressing the blade retainer is generated. This means that the blade is pressed against the blade base 33 via the blade retainer, whereby the blade 51 is pressed and fixed. When P is the total pressure of the total number of leaf springs at this time, this P is determined as follows.

First, the required pressure on the surface of the blade, that is, the pressure roller surface in the present embodiment, is set to F
Set to 1.

Next, between the blade base 33 and the blade support member 53, it is possible to absorb the strain during thermal expansion at the maximum use temperature, that is, between the blade base 33 and the blade support member at the maximum use temperature. Assuming that the maximum total pressure at which the members can slide is F2, P should be set so that F1 <P <F2. In other words, it is more than the pressure required for the pressure roller,
The pressure of the leaf spring may be determined within the slidable range.

As a result, oil is removed from the surface of the pressure roller with a required blade pressure, and the blade slides between the blade support member and the blade base during thermal expansion, so that the wavy or uneven contact of the blade It is possible to prevent contact failure such as.

(Second Embodiment) FIG. 5 shows an explanatory view of a second embodiment of the present invention.

FIG. 5 shows a detailed view of the oil removing blade 51. 52 is a blade made of fluororubber, 53
Is a blade support plate, and in the present embodiment,
The material is a phosphor bronze plate. A blade pressing member 54 is a member for fixing the blade to the blade base 33 with a uniform pressure. 57 is a screw with a spring washer for pressing and fixing the blade. The screw with spring washer 57 is
It is composed of a spring washer 57a and a flat washer 57b. Blade 51
Is fixed to the blade base 33 by a screw 57 with a spring washer via a blade pressing member 54.

By tightening the screws 57 with spring washers, the spring washers 57a generate a force for pressing the blade. As a result, the blade 51 is pressed and fixed. When the total pressure of the total number of screws 57 with spring washers at this time is P, this P is determined as follows.

First, the required pressure on the surface of the blade, that is, the surface of the pressure roller in this embodiment, is set to F
Set to 1.

Next, between the blade base 33 and the blade support member 53, it is possible to absorb the strain during thermal expansion at the maximum use temperature, that is, between the blade base 33 and the blade support member at the maximum use temperature. Assuming that the maximum total pressure at which the members can slide is F2, P should be set so that F1 <P <F2. In other words, it is more than the pressure required for the pressure roller,
The pressure of the screw with spring washer 57 may be determined within the slidable range, and the tightening torque of the screw may be actually determined.

As a result, the oil on the surface of the pressure roller is removed by the required blade pressure, and the blade slides between the blade supporting member and the blade base during thermal expansion. It is possible to prevent a contact failure such as a hit.

(Embodiment 3) FIG. 6 shows an explanatory view of a third embodiment of the present invention.

FIG. 6 shows a detailed view of the oil removing blade 51. 52 is a blade made of fluororubber, 53
Is a blade support plate, and in the present embodiment,
The material is a phosphor bronze plate. A blade pressing member 54 is a member for fixing the blade to the blade base 33 with a uniform pressure. Reference numeral 55 is a step screw for pressing and fixing the blade. Reference numeral 56 denotes a blade pressing leaf spring, which is integrated with the blade pressing member 54 by spot welding or burring caulking in the present embodiment. In the present embodiment, in the configuration described in the first embodiment, the shape of the leaf spring 56 is changed as shown in FIG. 6, and a plan view and a sectional view of the blade are omitted. The blade 51 is the blade base 3
3 through the blade pressing member 54, the step screw 55
Fixed in.

A blade pressing plate spring 56 is provided at a position corresponding to each stage screw fixing portion (four positions in this embodiment) of the blade pressing member 54. In this figure, the two-dot chain line of the leaf spring 56 is the shape before the step screw is tightened. By tightening the step screw 55,
The leaf spring 56 has a shape represented by a solid line,
That is, a force for pressing the blade retainer is generated. This means that the blade is pressed against the blade base 33 via the blade retainer, whereby the blade 51 is pressed and fixed. When P is the total pressure of the total number of leaf springs at this time, this P is determined as follows.

First, the required pressure on the surface of the blade, that is, the pressure roller in this embodiment, is set to F
Set to 1.

Next, between the blade base 33 and the blade support member 53, it is possible to absorb the strain during thermal expansion at the maximum use temperature, that is, between the blade base 33 and the blade support member at the maximum use temperature. Assuming that the maximum total pressure at which the members can slide is F2, P should be set so that F1 <P <F2. In other words, it is more than the pressure required for the pressure roller,
The pressure of the leaf spring may be determined within the slidable range.

As a result, oil is removed from the surface of the pressure roller by a required blade pressure, and the blade slides between the blade support member and the blade base during thermal expansion, so that the waviness of the blade It is possible to prevent contact failure such as.

(Embodiment 4) FIG. 7 shows an explanatory view of a fourth embodiment of the present invention. In the figure, contents common to those described in the first embodiment are omitted in the present embodiment.

Reference numeral 18 denotes an oil application blade made of an elastic material such as fluorine rubber for scraping off the oil O on the surface of the oil application roller 16 and applying a fixed amount of oil.
Reference numeral 64 denotes a blade base for supporting the oil coating blade 18, which is rotatably attached to the frame about a rotation center 64a. Oil coating blade 1
8 is urged by a spring 17 so that a constant pressure is always maintained against the surface of the coating roller 16. This regulates the amount of oil on the application roller to a predetermined amount.

In the present embodiment, the method of fixing the oil coating blade to the blade base is configured as described in the first to third embodiments, so that the wave of the blade is the same as in the previous embodiments. It is intended to prevent the inside of the roller and prevent a contact failure on the roller surface.

Since these blade fixing methods have been described in detail in the first to third embodiments and FIGS. 3 to 6, the description thereof will be omitted.

(Fifth Embodiment) FIG. 8 shows an explanatory view of a fifth embodiment of the present invention. In the figure, contents common to those described in the first embodiment are omitted in the present embodiment.

Reference numeral 62 denotes oil O on the surface of the fixing roller 10.
It is an oil application blade made of an elastic material such as fluorine rubber for scraping off a certain amount of oil. 63
Is a blade base for supporting the oil coating blade 62, and is rotatably attached to the frame about the rotation center 63a. Oil coating blade 62
Is urged by the spring 64 so that a constant pressure is always maintained against the surface of the fixing roller 10. As a result, the amount of oil on the fixing roller is regulated to a predetermined amount.

In this embodiment, the method of fixing the oil coating blade to the blade base is configured as described in the first to third embodiments, so that the wave of the blade is the same as in the previous embodiments. It is intended to prevent the inside of the roller and prevent a contact failure on the roller surface.

Since these blade fixing methods have been described in detail in the first to third embodiments and FIGS. 3 to 6, the description thereof will be omitted.

[0044]

As described above, the fixing roller for fixing the unfixed image on the recording material and the fixing roller are brought into pressure contact with each other,
A pressure roller that forms a nip for nipping and conveying the recording material,
A release agent applying means for applying a release agent to the surfaces of the fixing roller and the pressure roller and a blade means for wiping the release agent are provided.
The blade means and a blade member for wiping the release agent
Blade support and blade supporting this blade member
In a fixing device provided with a support pressing member for pressing the support, the support pressing member moves to the blade support.
The total pressure P is the contact pressure at which the blade member contacts the target object.
The blade support and the support pressing member slide against each other
Maximum possible support body pressing member to blade support
Since the pressure is smaller than the total pressure, the difference in thermal expansion can be absorbed between the blade support and the support pressing member even when a thermal expansion difference or thermal strain occurs due to high temperature.

Due to these things, the blade support,
Each thermal expansion difference between the support pressing member, to prevent defects such as distortion, proper contact failure between the blade edge and the roller, oil slipping through, cleaning performance that does not occur one-sided, The release agent wiping performance, the release agent scraping performance, and the release agent coating performance are obtained, and there is an effect that a high-quality image can be achieved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a fixing device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of a pressure roller oil removing blade portion of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a pressure roller oil removing blade portion of the image forming apparatus according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram of a pressure roller oil removing blade portion of the image forming apparatus according to the second embodiment of the present invention.

FIG. 6 is an explanatory diagram of a pressure roller oil removing blade portion of an image forming apparatus according to a third embodiment of the present invention.

FIG. 7 is an explanatory diagram of a fixing device according to a fourth embodiment of the present invention.

FIG. 8 is an explanatory diagram of a fixing device according to a fifth embodiment of the present invention.

FIG. 9 is an explanatory diagram of a fixing device in a conventional example.

[Explanation of symbols]

10 fixing roller 11 Pressure roller 33 blade stand 51 blade means 52 blade 53 Support plate 54 Presser member 55 screws 56 leaf spring

Claims (5)

(57) [Claims] 1. A fixing roller for fixing an unfixed image on a recording material, a pressure roller for pressing the fixing roller to form a nip for nipping and conveying the recording material, and a fixing roller and a surface of the pressure roller. Release agent applying means for applying a release agent and release agent
Blade means for wiping the
A blade member for wiping the release agent and this blade member are supported.
Blade support to hold and support to press the blade support
In a fixing device provided with a body pressing member, the total pressure P from the support pressing member to the blade support is
The contact pressure of the contact member with the target object is greater than
Support capable of sliding between the support member and the support pressing member
A fixing device characterized in that it is smaller than the maximum total pressure from the pressing member to the blade support . 2. A blade member fixing device according to claim 1, characterized in that a release agent regulating blade member in contact with the release agent application means. Wherein the blade member fixing device according to any one of claims 1 to 2, characterized in that contact with the fixing roller surface is a blade member for wiping a release agent. 4. A blade member is in contact with the surface of the pressure roller fixing device according to any one of claims 1 to 3, characterized in that the blade member for wiping a release agent. 5. An unfixed image in which an unfixed image is formed on a recording material.
In an image forming apparatus having an image means, an image forming apparatus
Is the fixing device according to any one of claims 1 to 4.
Prepare