JP2009300473A - Fixing member, fixing device using the same, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing member that has an excellent releasability from toner and an excellent separability from a fixed image for a long period and forms the fixed image having uniform gloss. <P>SOLUTION: In this fixing member 1 for fixing a toner image on a recording medium in the electrophotographic image forming apparatus, at least substrate 2 and an elastic layer 3 made of silicone rubber are stacked in this order(an elastic intermediate layer 4 may be included), the elastic layer 3 constitutes the outermost surface in contact with the toner image, and contains wax. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fixing member used in an image forming apparatus such as an electrophotographic copying machine or a printer, and more particularly to a fixing member suitably used in an oilless fixing device. The present invention also relates to a fixing device using such a fixing member.

  In recent years, image forming apparatuses such as copying machines and printers have been trending toward colorization, and it can be said that the ratio is gradually increasing. The color image forming apparatus includes a heating unit that heats at least four color (cyan, magenta, yellow, and black) toner images formed on a recording medium, a fixing member that fixes the toner image on the recording medium, and the fixing unit. And a pressure member for forming a fixing nip, and a fixing image is formed on the recording medium by heating and pressing the recording medium on which the toner image is formed when passing through the fixing nip. is there.

  However, since the fixing member comes into contact with the molten toner image, a so-called offset is easily generated in which a part of the toner image is transferred to the surface of the fixing member. In addition, a phenomenon that the recording medium is wound around the fixing member by the toner melted at the time of fixing, so-called jam may occur. Since these phenomena lead to contamination of the fixed image and failure of the member and the apparatus, various measures have been applied to the fixing member in order to improve the releasability between the fixing member and the toner and the separation property of the fixed image. Yes.

  For example, although a fixing roller (for example, Patent Document 1) in which a fluorine-containing elastomer containing 0 to 2 parts of polyethylene wax is molded on a roller core has been proposed, the wax exudes from the elastomer because it passes through an overheating process after mixing. The subject that the desired compounding quantity could not be hold | maintained remained.

  Therefore, in order to solve the above problems, an image recording apparatus (for example, Patent Document 2) using a fixing member in which a release layer made of fluororubber having high affinity for wax is impregnated with wax has been proposed. A large amount of the methylsiloxane compound cannot be uniformly mixed with the fluororubber so as to sufficiently increase the affinity, and it has been difficult to obtain an affinity enough to absorb the wax.

  In addition, for example, a toner that is used in an oilless fixing system and has been proposed in which polypropylene glycol is mixed in order to make offset difficult to occur (for example, Patent Document 3). However, a release agent in the toner is used as a fixing member. The problem remains that a good fixing function cannot be exhibited until it adheres to the surface to some extent.

  Therefore, in order to solve the above-mentioned problem, a fixing device (for example, Patent Document 4) in which the surface of the rotating member is coated with a fluororesin, silicone oil is applied to the rotating member, and a post-release agent is applied has been proposed. However, in the fixing device using the rotating member, as the number of images formed increases, the release agent on the surface of the rotating member decreases, and the problem remains that the releasability from the toner and the separability of the fixed image decrease. It was.

JP-A-61-192535 JP 2000-242115 A JP 2003-43746 A JP 2007-86754 A

  An object of the present invention is to provide a fixing member that is excellent in releasability from toner and fixed image separation over a long period of time and can form a fixed image having uniform gloss.

  As a result of intensive studies to solve the above problems, the present inventors have found that when the outermost layer of the fixing member is composed of a heat-resistant rubber containing wax, the releasability from the toner is excellent, and the fixed image The present inventors have found the fact that high-quality fixed images that are easy to separate and have no unevenness can be formed over a long period of time, and have completed the present invention.

  The above problems are solved by the following inventions (1) to (5) (hereinafter referred to as the present inventions 1 to 5). The fixing member in the present invention refers to a roller, a belt, a sheet, and the like, and the shape is not limited unless otherwise specified.

(1) A fixing member for fixing a toner image on a recording medium in an electrophotographic image forming apparatus, wherein at least an elastic layer is provided on a base material, the elastic layer is made of silicone rubber and wax is used. A fixing member that is contained and is provided so as to constitute an outermost surface in contact with a toner image.
(2) The fixing member according to (1), wherein the wax is solid at an environmental temperature in which the image forming apparatus is used.
(3) The fixing member according to (1) or (2), wherein the wax is the same as the wax contained in the toner forming the toner image.
(4) A fixing device comprising the fixing member according to any one of (1) to (3).
(5) An electrophotographic image forming apparatus comprising the fixing device according to (4).

  According to the first aspect of the invention, since the outermost surface constituting the fixing member contains the wax, the wax is replenished from the inside of the fixing member even if the toner image or the recording medium is absorbed during the fixing. It is possible to provide a fixing member that exhibits stable releasability.

  According to the second aspect of the invention, since the wax that is solid at the ambient temperature in which the image forming apparatus is used is contained, the wax does not bleed out and contamination of the peripheral portion of the apparatus can be prevented.

  According to the third aspect of the invention, since the same wax is contained in the fixing member and the toner, even if the wax is absorbed in the toner image or the recording medium at the time of fixing, not only from the inside of the fixing member but also from the subsequent toner image. Since the same wax is replenished, a stable releasability is exhibited over a long period of time, and a fixed image having a uniform gloss can be formed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Fixing member)
FIG. 1A is a cross-sectional view illustrating a configuration of a fixing member according to an embodiment of the present invention 1. The fixing member (1) is provided with an elastic layer (3) formed of silicone rubber and wax on a base material (2) through a primer layer (not shown). FIG. 1A shows an example of a fixing member in which the elastic layer is composed of only a single elastic layer (3). However, if the outermost surface in contact with the toner image is composed of silicone rubber and wax, for example, As shown in FIG. 1B, an elastic intermediate layer (4) that does not contain wax may be provided.

  Here, when the fixing member (1) is a fixing belt, the base material (2) may be a seamless belt made of a resin such as a polyimide resin, a polyamide resin or a polyamideimide resin, or a metal such as nickel or stainless steel. Preferably used. When the fixing member (1) is a fixing roller, a hollow pipe made of a metal such as aluminum, stainless steel, brass or copper, or glass or ceramics is preferably used as the substrate (2).

  The elastic layer (3) is formed by applying the silicone rubber solution or the like on the base material (2) through a primer layer (not shown) to form a coating layer, and heating the coating layer to cure. Thereafter, the laminate composed of the base material (2) and the elastic layer (3) is immersed in a liquid wax to obtain the fixing member (1) of the present invention containing the wax in the elastic layer (3). Moreover, as a coating method, spray coating, blade coating, dipping coating, die coating, etc. can be used by preparing the silicone rubber solution with an organic solvent or the like. In addition, it is preferable that it is 0.1-2 mm in the thinnest part as thickness of an elastic layer (3). If the thickness is less than 0.1 mm, the content of the release agent is insufficient and the releasability with the toner is lowered, or a sufficient nip width cannot be formed. Since it cannot fix, it is not preferable. On the other hand, if the thickness of the elastic layer (3) exceeds 2 mm, the heat capacity of the fixing member increases and the warm-up time becomes long.

  As a method for producing the fixing roller, for example, a core metal is placed inside a roller molding die, and then an uncured heat-resistant rubber composition is press-fitted into the cavity and cured. Thereafter, a method may be mentioned in which the rubber roller is taken out of the mold and, if necessary, secondary vulcanized and then impregnated with a release agent. In this case, the material, dimensions, and the like of the metal core can be appropriately selected according to the type of the roller, but aluminum, iron, stainless steel, or the like is preferably used as the material. In addition, it is preferable to perform primer processing, such as a silane coupling agent and a silicone type adhesive agent, on the surface of these metal cores for the purpose of further strengthening the adhesiveness with the elastic layer. In addition, it can also shape | mold by methods, such as transfer molding, injection molding, and coating, as needed.

  The fixing belt can be produced by the same method as the fixing roller. In this case, the belt base material is a metal belt such as nickel electroforming, SUS, or aluminum, polyimide resin, polyamide resin, polyamideimide resin. A known material such as an organic resin film can be used. Further, the shape, dimensions, and the like can be appropriately selected according to the type of belt.

(silicone rubber)
The silicone rubber in the present invention refers to a rubber composition mainly composed of polysiloxane, and in the range, the filler and anti-aging agent may be used depending on the purpose as long as the effects of the present invention are not impaired. Additives such as colorants and plasticizers can be optionally added. The silicone rubber is not particularly limited in kind and production method, but is preferably composed of one or more elastomers selected from the group of dimethyl silicone rubber, methylphenyl silicone rubber, and fluorosilicone rubber. Of these, dimethyl silicone rubber is preferably used from the viewpoint of easy absorption of wax.

  An example of the silicone rubber is a composition containing at least an organopolysiloxane having a structure represented by the following general formula (1). For example, DY35-2083 (Toray Dow Corning), KE1950-30 (Shin-Etsu Chemical) Company).

  An example of methylphenyl silicone rubber is a composition containing at least organopolysiloxane having a structure represented by the following general formula (2).

  An example of the fluorosilicone rubber is a composition containing at least an organopolysiloxane having a structure represented by the following general formula (3), such as X36-420 (Shin-Etsu Chemical Co., Ltd.), FSE7540, FSL7641 (momentive -Performance Materials), SE-1541-U (Toray Dow Corning), etc. are mentioned.

(wax)
Generally, a wax refers to an ester of a higher fatty acid and a monohydric or dihydric higher alcohol, and satisfies the following conditions.
(A) The solid has a melting point of 40 ° C. or higher.
(B) The melt viscosity is low.
(C) Do not decompose during melting.
(D) It is an organic compound.
However, in the present invention, neutral fats, higher fatty acids, hydrocarbons, and the like that show similar characteristics are also included. The difference between a wax and an organic polymer is not clear in many cases. For example, polytetrafluoroethylene (PTFE) may be classified as a wax, but it does not correspond to a wax because it has no melting point by definition.

  As the wax in the present invention, known ones can be mainly used. For example, plant waxes such as carnauba wax, candelilla wax, wood wax and rice wax; animal waxes such as beeswax and whale wax; mineral waxes such as montan wax; petroleum waxes such as paraffin wax and microcrystalline wax; -Synthetic waxes such as Tropsch wax, polyethylene wax, polypropylene wax, higher fatty acid esters and fatty acid amides; higher fatty acids such as lauric acid, myristic acid, palmitic acid and stearic acid and metal salts thereof. These waxes can be used alone or in combination. Of these, carnauba wax, paraffin wax, and microcrystalline wax are preferably used from the viewpoint of melting point, melt viscosity, and compatibility with heat-resistant rubber.

(Image forming device)
Next, an example of an electrophotographic image forming apparatus (for example, a copier or a printer) incorporating a fixing device having a fixing roller according to the present invention will be described.
In FIG. 2, an image forming apparatus (100) includes an image carrier (101) on which an electrostatic latent image is formed, a charging roller (102) that performs charging processing in contact with the image carrier (101), a laser beam, and the like. Exposure apparatus (103), developing roller (104) for attaching toner to the electrostatic latent image formed on the image carrier (101), and power source (105) for applying a DC voltage to the charging roller (102) A transfer roller (106) for transferring the toner image on the image carrier (101) onto paper (107), a cleaning device (108) for cleaning the image carrier (101) after the transfer process, and an image carrier. A surface potential meter (109) for measuring the surface potential of (101) and a fixing device (110) including a fixing roller (111) and a pressure roller (112).

  In this image forming apparatus (100), a photosensitive layer of a rotating image carrier (101) is uniformly charged using a charging roller (102), and then exposed by an exposure apparatus (103) such as a laser beam to be static. An electrostatic latent image is formed, the electrostatic latent image is developed with toner to form a toner image, and the toner image is transferred onto a transfer medium (107). Then, the transfer medium (107) having this toner image is passed through a fixing device (110) comprising a fixing roller (111) and a pressure roller (112), and the toner image adhering to the transfer medium (107) is transferred. The fixing roller (111) is softened by heat and pressed to fix it on the transfer medium (107), and is discharged to a paper discharge unit. In this case, the fixing member of the present invention is preferably used as the fixing roller (111). In the configuration of FIG. 2, the fixing member has a roller shape, but may be a belt shape. The belt-shaped fixing device will be described next.

  Further, an example of an electrophotographic image forming apparatus incorporating a fixing device having a fixing belt according to the present invention will be described. In the image forming apparatus (120) of FIG. 3, (121) is an image carrier, (122) is a charging device, (123) is a laser writing unit, (124) is a developing device, and (125) is a transfer roller. In the figure, (126) is a paper feeding unit, (127) is a paper feeding roller, (128) is a registration roller pair, (129) is a transfer medium, (130) is a cleaning device, (131) is a fixing device, ( Reference numeral 132) denotes a paper discharge unit. The fixing belt of the fixing device (131) is constituted by a fixing belt having a configuration according to the present invention.

  The image carrier (121) is rotationally driven in the direction of the arrow in the figure by a driving means (not shown), the surface is uniformly charged by the charging device (122), and then exposed to the surface by exposure from the laser writing unit (123). A latent image is formed. The latent image is visualized by the developing device (124), and transferred onto the transfer medium (129) supplied from the paper supply unit (126) via the paper supply roller (127), the registration roller pair (128), and the like. Then, the image is transferred by the transfer roller (125). The toner remaining on the surface of the image carrier (121) after the toner image transfer is removed by the cleaning device (130). The transfer medium (129) to which the toner image has been transferred is introduced into the fixing device (131), and the toner image is fixed on the transfer medium (129) by heating and pressing, and then discharged to the paper discharge unit (132). Paper.

Next, an example of a fixing device incorporating a fixing belt will be described as an example of the fixing member in the present invention. In the belt fixing device (140) of FIG. 4, (141) is a fixing belt, (142) is a heating roller, (143) is a fixing roller, (144) is a pressure roller, (145) is a halogen heater, (146) Is a temperature sensor. The fixing belt (141) has a configuration according to the present invention.
A fixing roller (143) having an elastic layer made of heat-resistant rubber on the surface of the metal pipe, and a heating roller (142) incorporating a first halogen heater (145a) inside the metal pipe are provided. For example, a fixing belt (141) in which an outermost layer composed of silicone rubber and a release agent is formed on a surface of a polyimide seamless belt via a primer is stretched between the rollers. A pressure roller (144) is pressed against the fixing roller (143) via a fixing belt (141). The pressure roller (144) has a structure in which an elastic layer made of heat-resistant rubber is provided on the surface of a metal pipe, and a second halogen heater (145b) is built inside.

  The fixing belt (141) is stretched without slack by urging the heating roller (142) in a direction away from the fixing roller (143) or separately providing a tension roller (not shown). The surface temperatures of the heating roller (142) and the pressure roller (144) are detected by the sensors (146a) and (146b) and controlled so as to be a predetermined set temperature. The surface temperature of the heating roller (142) may be detected by the sensor (146c) on the fixing belt (141) stretched between the heating roller (142) and the fixing roller (143).

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.
[Example 1]
(Fixing belt production)
Spray coating of silicone rubber primer (Toray Dow Corning, DY39-067) on the surface of polyimide seamless belt with inner diameter of 60mm, width of 400mm and thickness of 0.1mm to a thickness of 0.5μm After air drying at room temperature for 30 minutes, the mixture was heated at 150 ° C. for 30 minutes.
Next, the primer-treated belt base material is fixed to a mandrel, and a 50% toluene solution of silicone rubber (Toray Dow Corning, DY35-2083) is spray-coated, and in this state, primary application at 150 ° C. for 10 minutes is performed. After vulcanization, a rubber layer having a thickness of 0.2 mm was formed through secondary vulcanization at 200 ° C. for 4 hours. Thereafter, the obtained belt was immersed in carnauba wax (acid value 0.5, melting point 85 ° C.) heated to 140 ° C. for 10 minutes, and the wax adhering to the surface after lifting was wiped off. Finally, a fixing belt containing 1.0% wax with respect to the weight of the elastic layer was obtained.

[Example 2]
Instead of the carnauba wax, the same process as in Example 1 was performed except that paraffin wax HNP9 (Nippon Seiwa Co., Ltd., melting point 75 ° C.) was used. A fixing belt was obtained.

[Example 3]
Instead of the carnauba wax, the same process as in Example 1 was used except that microcrystalline wax Hi-Mic-1070 (Nippon Seiwa Co., Ltd., melting point 79 ° C.) was used. A fixing belt containing the wax was obtained.

[Comparative Example 1]
On the rubber layer obtained in Example 1, a fluororesin-containing primer was spray-coated and then naturally dried to form a primer layer having a thickness of 2 μm. Further, on this primer layer, a PFA (perfluoroalkoxyalkane) aqueous dispersion PFA945HP-Plus (Mitsui / DuPont Fluorochemical) is spray-coated to form a coating layer having a thickness of 30 μm. A release layer was formed by baking at 340 ° C. for 30 minutes. Thereafter, the obtained belt was dipped in carnauba wax (acid value 0.5, melting point 85 ° C.) heated to 140 ° C. for 10 minutes and then pulled up, and the wax (1.0 mg / cm ² ) adhered to the surface of the release layer. A fixing belt was obtained.

[Comparative Example 2]
Instead of the carnauba wax, oil (1.0 mg / cm ² ) was formed on the surface of the release layer through the same process as Comparative Example 1 except that dimethyl silicone oil KF-96-100cs (Shin-Etsu Chemical Co., Ltd.) was used. An attached fixing belt was obtained.

(Evaluation of releasability from toner and paper)
The evaluation conditions are as follows.
Copier: RICOH imagio MP C2500 remodeling machine (without oil application mechanism)
Print original: Halftone (400 dpi, 50%)
Printing mode: full color, single side Recording medium: fine paper, type 6200, A4 size (Ricoh)
Evaluation interval: Every 200 sheets up to the first 1000 printed sheets, and every 1000 sheets thereafter up to 5000 sheets.
Toner: imagio spot toner C3000

Under the above conditions, the fixing belts obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were installed to perform printing, and when the predetermined number of prints was reached, the surface of the fixing member was observed to observe toner offset. The presence or absence was confirmed. Further, the presence or absence of toner transferred from the surface of the fixing member to the paper through the white paper was visually confirmed. The presence or absence of jamming in the fixing device was also confirmed.
The evaluation criteria were as follows.
○: No toner offset or jam occurred ×: Toner offset or jam occurred

(Evaluation of image quality)
The first and 1000th images printed under the above conditions were visually checked for gloss unevenness.
◯: No gloss unevenness was observed in the image ×: Uneven gloss was observed in the image The evaluation results were as shown in Table 1 below.

In Examples 1 to 3, toner offset and jam were not observed even after printing 5000 sheets. On the other hand, in both Comparative Examples 1 and 2, a jam occurred before 1000 sheets were printed.
Regarding the image quality, no unevenness was found in the output images of Examples 1 to 3. On the other hand, in Comparative Examples 1 and 2, a jam occurred before 1000 sheets were printed, and as a result, the image quality was confirmed with the immediately preceding image.
As can be seen from Table 1, which is the experimental result, the fixing member of the present invention is superior in the releasability from the toner and the separability of the fixed image as compared with the comparative example, and a high-quality fixed image without unevenness is obtained. It was confirmed that

  The fixing member of the present invention is excellent in releasability from toner and separation of a fixed image over a long period of time and can form a fixed image having uniform gloss. Therefore, an electrophotographic copying machine and printer It can be suitably used as a fixing member for a fixing device used in an image forming apparatus such as an oil-less fixing device.

FIG. 3 is a cross-sectional view illustrating a configuration of a fixing member that is one embodiment of the present invention. 1 is a schematic configuration diagram for explaining an example of an image forming apparatus incorporating a fixing device including a fixing roller according to the present invention. 1 is a schematic configuration diagram for explaining an example of an image forming apparatus incorporating a fixing device including a fixing belt according to the present invention. It is a block diagram of a belt fixing device.

Explanation of symbols

(About Figure 1)
DESCRIPTION OF SYMBOLS 1 Fixing member 2 Base material 3 Elastic layer 4 Elastic intermediate | middle layer (about FIG. 2)
DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Image carrier 102 Charging roller 103 Exposure apparatus 104 Developing roller 105 Power supply 106 Transfer roller 107 Transfer medium 108 Cleaning apparatus 109 Surface potential meter 110 Fixing apparatus 111 Fixing roller 112 Pressure roller (about FIG. 3)
120 image forming apparatus 121 image carrier 122 charging device 123 laser writing unit 124 developing device 125 transfer roller 126 paper feeding unit 127 paper feeding roller 128 registration roller pair 129 transfer medium 130 cleaning device 131 fixing device 132 paper discharge unit (about FIG. 4) )
140 Belt fixing device 141 Fixing belt 142 Heating roller 143 Fixing roller 144 Pressure roller 145 Halogen heater 146 Temperature sensor

Claims (5)

  A fixing member for fixing a toner image on a recording medium in an electrophotographic image forming apparatus, wherein at least an elastic layer is provided on a substrate, and the elastic layer is made of silicone rubber and contains a wax. And a fixing member provided so as to constitute an outermost surface in contact with the toner image.   The fixing member according to claim 1, wherein the wax is solid at an environmental temperature in which the image forming apparatus is used.   The fixing member according to claim 1, wherein the wax is the same as the wax contained in the toner forming the toner image.   A fixing device comprising the fixing member according to claim 1.   An electrophotographic image forming apparatus comprising the fixing device according to claim 4.

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