JP2005017744A - Fixing roller, mask tool, manufacturing method of fixing roller, fixing device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fixing roller for which a thin core bar is used, in which the variance of the thickness of silicone rubber is made small and further which surely prevents coating liquid from adhering to a journal part. <P>SOLUTION: The fixing roller has an elastic layer composed of heat resistant rubber such as silicone rubber and a mold-released layer composed of fluororesin successively on the metallic hollow core bar 1. Steps 1d for keeping the outside diameter of the mask tool for masking the coating of the elastic layer equal to the outside diameter of the barrel part 1a of the core bar 1 are respectively provided on both sides in the axial direction of the barrel part 1a of the core bar 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing roller, a mask jig, a fixing roller manufacturing method, a fixing device thereof, and an image forming apparatus thereof, which are used in an electrophotographic fixing device.
[0002]
[Prior art]
FIG. 10 is an explanatory diagram of a conventional electrophotographic image forming apparatus. A conventional electrophotographic image forming apparatus 64, such as a copying machine and a laser printer, includes a photosensitive drum 64a on which an electrostatic latent image is formed, a charging roller 64b that performs charging processing in contact with the photosensitive drum 64a, and a laser. Recording means 64c, a developing roller 64e for attaching toner to the electrostatic latent image on the photosensitive drum 64a, a power pack 64h for applying a DC voltage to the charging roller 64b, and a toner image on the photosensitive drum 64a. A transfer roller 64f for transferring to the paper P, a cleaning device 64g for cleaning the photoconductor drum 64a after the transfer processing, a surface potential meter 64d for measuring the surface potential of the photoconductor drum 64a, a heat fixing roller T and a heating roller It is constituted by a roller type heat fixing device TS composed of a pressure roller K. The image forming apparatus 64 is for forming a black and white image. When a full color image is formed with this, the four colors of red; magenta, blue; cyan, yellow; yellow, and black; black are used. Therefore, it is necessary to provide a developing device for each color and a mechanism for superposing them.
[0003]
The image forming apparatus 64 using this electrophotographic system uniformly charges a photosensitive layer of a rotating photosensitive drum 64a using a charging roller 64b, and then exposes it with an exposure unit 64c such as a laser beam to electrostatic latent. An image is formed, and the electrostatic latent image is developed with toner to form a toner image. The toner image is transferred onto the recording paper P, and the recording paper P is transferred from the heat fixing roller T and the pressure roller K. The toner image is thermally fixed by being passed through a roller type heat fixing device TS.
[0004]
As shown in FIG. 9, in such a heat fixing device TS of the image forming device 64, the heat fixing roller T has a heater Th such as a halogen lamp disposed in the hollow portion of the core metal along the rotation center line. The heat fixing roller T is heated from the inside by the radiant heat, and the recording paper P is passed through the nip N between the heat fixing roller T and the pressure roller K, so that The toner t adhering to the toner is pressed while being softened by the heat of the heat-fixing roller T and fixed onto the recording paper P.
[0005]
In recent years, in an apparatus using this thermal fixing method, it is desired to improve the image quality of a fixed image at the same time as shortening the temperature raising time of the fixing roller surface, that is, the so-called warm-up time. To shorten the warm-up time, a great effect can be obtained by reducing the thickness of the core metal of the fixing roller. However, since the rigidity is important in terms of its function, it cannot be reduced so much.
[0006]
If the core metal thickness of the fixing roller is reduced, the strength of the core metal is reduced, and the core metal of the fixing roller is easily deformed by the pressing force against the pressure roller, so that a stable fixed image cannot be obtained.
[0007]
As a countermeasure, as shown in JP-A No. 2002-126824, JP-A No. 2002-126904, etc., by providing a plurality of ribs on the inner surface of the cored bar, the ribs on the inner side are secured while ensuring a warm-up time as a thin cored bar The core metal is prevented from being crushed and a stable fixed image is obtained.
[0008]
In addition, in a color fixing device, a thick elastic layer of about 0.1 mm to 0.5 mm is necessary in order to have an enveloping effect on the unevenness of multilayer toner, and good fixing properties and recording paper High thickness accuracy is required to ensure the carry-out characteristics. For this elastic layer, heat-resistant silicone rubber or fluorine rubber is used.
[0009]
Conventionally, as a method of forming the elastic layer of the fixing roller,
(A) A method of supporting the cored bar vertically with respect to the coating material (silicone rubber) surface, immersing the cored bar in the coating material, and then pulling it up (vertical dip),
(B) A method in which the metal core is horizontally supported with respect to the coating material, and the outer peripheral surface is brought into contact with and immersed in the coating material while rotating the roller, and then pulled up (horizontal dip),
(C) A method in which a coating material is supplied between a blade (knife) and a rotating metal core, and an elastic layer is formed between the blade and the metal core (blade coating),
(D) A method of spraying while rotating the cored bar (spray coating),
(E) A method in which a core metal is placed in a mold and a coating material is injected between the core metal and the mold (casting),
and so on.
[0010]
However, each of these conventional methods has the following problems.
(A) Since a coating material adheres to the edge part which does not need to apply | coat the vertical dip, the process of removing this coating material is required.
(B) When the horizontal dip is pulled up from the coating material, it becomes partially thick due to surface tension.
(C) Similarly to the horizontal dip, the blade paint scrapes off the coating material, and the cut portion becomes partially thick due to surface tension.
(D) The edge of the coating material becomes partially thick due to surface tension. Also, when it gets thicker, it must be painted several times, but the appearance is good.
(E) Since a thin cored bar has low rigidity, the cored bar is deformed in casting under pressure.
[0011]
In addition, the above (a) to (e) are allowed to stand for several minutes to several tens of minutes after painting, and if the leveling is performed, the painted surface becomes smooth, but when the coating becomes thick, the coating material droops and the thickness varies. There is also a problem. The sagging of the coating material supports the cored bar horizontally, and several r. p. It can be prevented by rotating slowly at about m.
[0012]
When the roller thus coated is vulcanized (heated) in an electric furnace, the coating material at the top of the roller becomes thin due to the effect of gravity, and a liquid lump is formed at the lower end, resulting in a thick film. A difference in thickness occurs.
[0013]
In order to prevent this, there is a method in which the roller is horizontally supported and heated while rotating to cure the coating material, but the equipment becomes enormous.
[0014]
In addition, when the thickened part is polished after painting, a smooth surface can be obtained, but since it is necessary to clean the polishing powder on the surface after polishing, it is necessary to increase the number of manufacturing steps and increase the manufacturing cost. is there.
[0015]
As a vertical dip, there is a technique disclosed in Japanese Patent Laid-Open No. 7-225525. In this fixing roller, a jig having the same diameter as that of the cored bar body is coupled to both ends of a roller cored bar made of aluminum or the like formed to have a thickness of 3 mm or less so that uneven flow of the rubber coating liquid does not occur at the end of the cored bar. In such a manner, it is produced by forming a silicone rubber coat layer on the cored bar by pulling it up from the silicone rubber coating solution, dipping, and forming a silicone rubber coat layer on the cored bar.
[0016]
[Patent Document 1]
JP 2002-126824 A [Patent Document 2]
JP 2002-126904 A [Patent Document 3]
Japanese Patent Laid-Open No. 7-225525
[Problems to be solved by the invention]
However, in the above-described coating methods (a) to (e), there is a problem in that it is necessary to mask the end portion (journal portion) that does not need to be applied or to remove the coating material adhering to unnecessary portions. there were.
[0018]
Especially in the vertical dip, the journal part is immersed in the coating material, so if the core metal and mask jig are not made with high precision, the coating material will infiltrate from the gap between the mask jig and the core metal and adhere to the journal part. End up.
[0019]
When the mask jig is brought into contact with the end portion of the core portion of the core metal as in the method described in JP-A-7-225525, as shown in FIG. 11, the body portion 1a and the journal portion 1c. If the conventional cored bar 100 in which the shoulder portion 1b is formed by drawing is used, the tip of the mask 104 is brought into contact with the shoulder portion 1b as shown in FIG. When vertical dipping is performed using the metal core 100 and the mask 104, the shape accuracy of the shoulder portion 1b is rough, so that the sealing performance between the shoulder portion 1b and the mask 104 is poor, and the hydraulic pressure is reduced by the vertical dipping. When added, silicone rubber may adhere to the journal part 1c. Further, when the silicone rubber adheres to the journal portion 1c, there is a problem that a process for removing the coating material is required, resulting in poor productivity and high cost.
[0020]
Therefore, the present invention can use a thin cored bar, can reduce variations in the thickness of the silicone rubber, and can reliably prevent the coating liquid from adhering to the journal portion. An object of the present invention is to provide a mask jig, a fixing roller manufacturing method, a fixing device, and an image forming apparatus.
[0021]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 is characterized in that an elastic layer made of a heat-resistant rubber such as silicone rubber and a release layer made of a fluororesin are formed on a metal hollow core metal. In the fixing roller having sequentially,
Step portions for holding the mask jig for masking the coating of the elastic layer so that the outer diameter of the mask jig is equal to the outer diameter of the hollow core metal barrel are provided on both axial sides of the hollow core metal barrel. A fixing roller.
[0022]
According to a second aspect of the present invention, the mask jig is composed of an outer portion and an inner portion, the outer portion is formed of a cylindrical member held by the stepped portion, and the inner portion is a journal of the hollow cored bar. The fixing roller according to claim 1, comprising a metal core holding member fitted into the portion.
[0023]
The invention according to claim 3 is the fixing roller according to claim 1 or 2, wherein the coating is spray coating.
[0024]
According to a fourth aspect of the present invention, the metal core holding member includes an elastic body that presses the cylindrical member against the hollow metal core end along the stepped portion. A mask jig used in the manufacture of the fixing roller described in 1.
[0025]
According to a fifth aspect of the present invention, there is provided a fixing roller having, on a metal hollow core metal, an elastic layer composed of a heat-resistant rubber such as silicone rubber and a release layer composed of a fluororesin in order. In the method
The outer diameter of the mask jig for masking the coating of the elastic layer is made equal to the outer diameter of the body of the hollow core metal at the step portions provided on both axial sides of the body of the hollow core metal. The mask jig is held, and then at least the body of the hollow core metal is coated with silicone rubber, and then the silicone rubber is cured with the painted hollow core metal standing vertically, and then the mask jig A fixing roller manufacturing method, wherein the fixing roller is removed.
[0026]
According to a sixth aspect of the present invention, the mask jig is composed of an outer portion and an inner portion, the outer portion is formed of a cylindrical member held by the step portion, and the inner portion is a journal of the hollow cored bar. The fixing roller manufacturing method according to claim 5, comprising a cored bar holding member fitted into the portion.
[0027]
According to a seventh aspect of the invention, the core metal holding member includes an elastic body that presses the cylindrical member against the end of the hollow core metal along the stepped portion. The fixing roller manufacturing method described in the above.
[0028]
An eighth aspect of the invention is a fixing device including the fixing roller according to any one of the first to fourth aspects.
[0029]
A ninth aspect of the present invention is an image forming apparatus including the fixing device according to the eighth aspect.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing a basic configuration of a fixing roller used in the present invention.
As shown in FIG. 1, a metal core 1, a heat-resistant rubber elastic layer 2, and a fluororesin release layer 3 are sequentially provided from the center of the roller cross section. There may be an adhesive layer between the cored bar 1 and the elastic layer 2 or between the elastic layer 2 and the release layer 3, if necessary, and between the cored bar 1 and the elastic layer 2 and the elastic layer. There may be an adhesive layer between 2 and the release layer 3 as necessary.
[0031]
FIG. 2 is a view showing a core bar used in the fixing roller of the present invention.
As shown in FIG. 2, the outer diameter of the end portion of the body portion 1a of the core metal 1 is reduced to form a step 1d concentric with the journal portion 1c.
[0032]
(Example 1)
As shown in FIG. 1, the core metal 1 is made of an aluminum alloy hollow pipe, and as shown in FIG. 2, the journal portion 1c is reduced in diameter by drawing. In order to shorten the warm-up time, the body portion 1a is thinned and has a thickness of 0.4 mm, and the journal portion 1c has a thickness of 1 mm or more for ensuring strength.
[0033]
Usually, the outer diameter of the body portion 1a is φ40 to 50 mm, and the outer diameter of the journal portion 1c is φ20 mm to φ30 mm. Since the shoulder 1b between the body 1a and the journal 1c does not function when the fixing roller is used, machining such as cutting is not performed after the drawing. For this reason, the shape of the shoulder 1b is rough.
[0034]
As shown in FIG. 2, the step 1 d that holds the mask jig for masking the coating of the elastic layer 2 so that the outer diameter of the mask jig is equal to the outer diameter of the body 1 a of the core 1 is the body 1 a of the core 1. Are provided on both sides in the axial direction.
[0035]
FIG. 3 is a view showing a state in which a mask jig is mounted on the cored bar of FIG. 2 according to the first embodiment of the present invention, and FIG. 4 is a vertical stand with the mask jig mounted on the cored bar of FIG. FIG. With reference to FIG. 3, FIG. 4, the coating of the silicone rubber using the metal core (FIG. 2) of this invention is demonstrated.
[0036]
As shown in FIG. 3, the mask tip 4 a of the mask 4 is thin to match the roller shape so as to cover the step 1 d of the core 1. Since the mask end is thin and does not have rigidity, the mask is shaped so as not to hit the shoulder 1b, and the end of the body 1a of the core 1 is received by abutment.
[0037]
In this way, the journal portion 1c is covered with the mask 4 so that unnecessary silicone rubber does not adhere to the journal portion 1c. In the method of coating by rotating the core 1 such as horizontal dip, blade coating, spray coating, etc., the surface of the inner surface of the mask 4 that receives the journal portion 1c is high because the runout of the core 1 affects the film thickness variation. It is formed with accuracy.
[0038]
The outer diameter of the mask 4 and the outer diameter of the body portion 1a of the cored bar 1 are substantially the same, and in this embodiment, φ40. That is, the outer diameter of the mask 4 and the outer diameter of the body portion 1a of the core metal 1 are formed substantially flush with each other. Silicone rubber was applied to the region including the body portion 1a of the core 1 by spray coating so as to have a film thickness of 500 μm. As shown in FIG. 4, the coated roller is left standing for 30 minutes with the mask 4 on, and then placed in an electric furnace to cure the silicone rubber that becomes the elastic layer 2, and then the mask 4 is removed. It was. When the roller is left standing, the silicone rubber drips, but the silicone rubber is supplied from the mask 4 to the upper part of the roller body 1a, and the silicone rubber flows from the lower part of the roller body 1a to the mask 4. Thus, a uniform film was obtained on the body 1a of the roller.
[0039]
(Example 2)
FIG. 5 is a diagram showing a state in which a mask jig is mounted on the cored bar of FIG. 2 according to the second embodiment of the present invention, and FIG. 6 is a vertical stand with the mask jig mounted on the cored bar of FIG. FIG. With reference to FIG. 5 and FIG. 6, the coating of silicone rubber using the cored bar (FIG. 2) of the present invention will be described.
[0040]
In this second embodiment, the mask is made of a core metal holding member 41 (inner portion) made of aluminum alloy, and a cylindrical film 42 made of SUS or polyimide having an outer diameter substantially the same as that of the core metal barrel portion (outer portion). ). The cored bar 1 was held by the cored bar holding member 41 in the same manner as in Example 1, and silicone rubber was applied with a film thickness of 500 μm by spray coating.
[0041]
After the silicone rubber was painted on the roller, the core metal holding member 41 was removed. At this time, since the step 1d is formed on the core metal 1, the cylindrical film 42 does not come off the roller without the core metal holding member 41. As shown in FIG. 6, the coated roller was allowed to stand for 30 minutes in a vertical state, then placed in an electric furnace to cure the silicone rubber, and then the cylindrical film 42 was removed.
[0042]
Silicone rubber drips when the roller is left standing, but silicone rubber is supplied from the cylindrical film 42 to the upper part of the roller body 1a, and from the lower part of the roller body 1a to the cylindrical film 42. Silicone rubber flowed and a uniform film was obtained on the body 1a of the roller.
[0043]
Example 3
FIG. 8 relates to a third embodiment of the present invention and shows a state where a mask jig is attached to the cored bar of FIG.
As shown in FIG. 8, the mask has a core metal holding member 41, a cylindrical film 42 whose outer diameter is substantially the same as that of the core metal barrel, and a cylinder facing the end of the barrel 1 a of the core 1. The core film 1 was held by the elastic film 43 and the core metal 1 was held, and a silicone rubber was applied by 500 μm by spray coating. In this mask, the cylindrical film 42 is pressed against the end of the body 1a of the core 1 at the time of painting so that there is no gap between the core 1 and the cylindrical film 42.
[0044]
The metal core 1 was held with such a mask, and silicone rubber was applied with a film thickness of 500 μm by spray coating. The coated roller was left standing for 30 minutes with the mask on, and then placed in an electric furnace to cure the silicone rubber, and then the mask was removed.
[0045]
Silicone rubber drips when the roller is left standing, but silicone rubber is supplied from the cylindrical film 42 to the upper part of the roller body 1a, and from the lower part of the roller body 1a to the cylindrical film 42. Silicone rubber flowed and a uniform film was obtained on the body 1a of the roller.
In the above embodiments, spray coating is used as an example, but the same effect can be obtained by horizontal dipping and blade coating.
[0046]
(Comparative example)
On the other hand, the cored bar 1 was held with a mask in the same manner as in Example 1, and silicone rubber was applied by 500 μm by spray coating. The mask was removed from the painted roller, left standing for 30 minutes, and then placed in an electric furnace to cure the silicone rubber. As shown in FIG. 7, the silicone rubber sags, and the silicone film thickness is reduced at the upper end portion, and the silicone rubber is accumulated at the lower end portion to form the retention portion 2a. The thickness of this portion is increased.
[0047]
The fixing roller of the present invention is used as a fixing roller used in an image forming apparatus as shown in FIG. Although a halogen heater is often used as a heat source for the fixing roller, there is no problem even if the induction heating method described in Japanese Patent Application Laid-Open Nos. 2001-242732 and 2001-13805 is used.
[0048]
In addition, power supply to the heating source is performed from a commercial power source, but an auxiliary power source may be provided to supply power from the auxiliary power source. As the auxiliary power source, it is preferable to use an electric double layer capacitor as disclosed in JP-A No. 2002-174988.
In addition, this invention is not limited to the said Example. That is, various modifications can be made without departing from the scope of the present invention.
[0049]
【The invention's effect】
As described above, according to the first or third aspect of the invention, by forming the elastic layer of the fixing roller as a silicone rubber coat layer formed by coating, a thin hollow core metal can be used. The variation in rubber thickness can be reduced, and it is possible to reliably prevent the coating liquid from adhering to the journal part, so even when used in a color fixing device, the warm-up time is short and good. A color image can be formed.
[0050]
In addition, since the outer diameter of the end surface of the hollow core metal corresponding to the end position of the elastic layer is smaller than that of the core metal body, variation in thickness can be reduced, so that the fixing property is improved and the recording paper Even when the silicone rubber coating layer capable of improving the transportability is used in a color fixing device having a large endurance load and no local unevenness and thickness variation, a better color image can be formed.
[0051]
In addition, according to the invention of claim 2 or 6, since the cored bar holding member in the inner part can be removed when curing after coating, it can be used for coating other workpieces. The core metal holding member is not used in large quantities, and the manufacturing cost can be reduced during mass production.
[0052]
According to the invention of claim 4 or 7, since the cylindrical member is pressed against the roller by an elastic body, the gap between the roller and the mask can be surely eliminated even if the shape of the shoulder portion of the hollow core metal varies. Therefore, it is possible to manufacture a thin hollow core metal with a small variation in the thickness of the silicone rubber at a low cost.
[0053]
According to the invention of claim 5, a mask jig having the same outer diameter as that of the core metal is disposed at the end of the hollow core metal, and silicone is applied to a part or all of the core metal and the mask jig by painting. Since the rubber is formed and the silicone rubber is cured in a state where the hollow cored bar is erected vertically, the variation in the thickness of the silicone rubber can be reduced.
[0054]
According to the invention of claim 8, a fixing device having the effect of any one of claims 1 to 4 can be obtained.
[0055]
According to the ninth aspect of the invention, an image forming apparatus having the effect of the ninth aspect can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a basic configuration of a fixing roller of the present invention.
FIG. 2 is a view showing a hollow metal core used in the fixing roller of the present invention.
FIG. 3 is a diagram illustrating a state where a mask jig is attached to the hollow cored bar of FIG. 2 according to the first embodiment of the present invention.
4 is a view showing a state in which the hollow cored bar of FIG. 3 is painted in a vertically standing state with a mask jig mounted thereon.
FIG. 5 is a diagram showing a state in which a mask jig is mounted on the hollow cored bar of FIG. 2 according to a second embodiment of the present invention.
6 is a view showing a state in which the hollow cored bar of FIG. 5 is coated in a vertically standing state with a mask jig attached. FIG.
7 is a view showing a comparative example in which the hollow cored bar of FIG. 11 is painted vertically.
FIG. 8 is a diagram showing a state where a mask jig is mounted on the hollow cored bar of FIG. 2 according to a third embodiment of the present invention.
9 is a diagram illustrating a fixing device provided in the image forming apparatus of FIG.
FIG. 10 is an explanatory diagram illustrating a main configuration of the image forming apparatus.
FIG. 11 is a view showing a hollow core bar used in a conventional fixing roller.
FIG. 12 is an explanatory view of silicone rubber coating using the conventional cored bar shown in FIG. 11;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Core metal 1a Body part 1b Shoulder part 1c Journal part 1d Step 2 Elastic layer 2a Stay part 3 Release layer 4 Mask 4a Mask tip part 41 Core metal holding member 42 Cylindrical film 43 Elastic body t Toner K Pressure roller N Nip P paper T fixing roller Th heater TS fixing device

Claims (9)

In a fixing roller having an elastic layer made of heat-resistant rubber such as silicone rubber and a release layer made of fluororesin in order on a metal hollow core metal,
Step portions for holding the mask jig for masking the coating of the elastic layer so that the outer diameter of the mask jig is equal to the outer diameter of the hollow core metal barrel are provided on both axial sides of the hollow core metal barrel. A fixing roller. The mask jig is composed of an outer portion and an inner portion, the outer portion is made of a cylindrical member held by the stepped portion, and the inner portion is fitted to the journal portion of the hollow core bar. The fixing roller according to claim 1, comprising a member. The fixing roller according to claim 1, wherein the coating is spray coating. 3. The fixing roller according to claim 2, wherein the core metal holding member includes an elastic body that presses the cylindrical member against the end of the hollow core metal along the stepped portion. 4. Mask jig. In a method for manufacturing a fixing roller, which has an elastic layer composed of a heat-resistant rubber such as silicone rubber and a release layer composed of a fluororesin in order on a metal hollow core metal,
The outer diameter of the mask jig for masking the coating of the elastic layer is made equal to the outer diameter of the body of the hollow core metal at the step portions provided on both axial sides of the body of the hollow core metal. The mask jig is held, and then at least the body portion of the hollow core metal is coated with silicone rubber, and then the silicone rubber is cured with the painted hollow core metal standing vertically, and then the mask jig A fixing roller manufacturing method, wherein the fixing roller is removed. The mask jig is composed of an outer portion and an inner portion, the outer portion is made of a cylindrical member held by the stepped portion, and the inner portion is fitted to the journal portion of the hollow core bar. The method for manufacturing a fixing roller according to claim 5, comprising a member. The method for manufacturing a fixing roller according to claim 6, wherein the cored bar holding member includes an elastic body that presses the cylindrical member against the end of the hollow cored bar along the stepped part. A fixing device comprising the fixing roller according to claim 1. An image forming apparatus comprising the fixing device according to claim 8.

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