JP2006276303A - Fixing roll, fixing device, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing roll which maintains high wear resistance and heat efficiency, has excellent releasing properties, and can stably form an image of good quality, to provide a fixing device which uses the fixing roll and can obtain a stable fixed image, and to provide an image forming apparatus which uses the fixing roll and can perform excellent picture quality formation. <P>SOLUTION: The fixing roll includes an electroless nickel plating layer 1 in which fluorocarbon resin particles are dispersed as a surface layer on a cylindrical cored bar 3 and surface roughness Rz of the electroless nickel plating layer is 1 to 6 μm. The fixing device uses the fixing roll and the image forming apparatus uses highly releasable toner and includes the fixing device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fixing roll applied to an electrophotographic copying machine, a printer, a facsimile, and the like, and a fixing device and an image forming apparatus using the fixing roll.

  Copiers, printers, facsimile machines, and the like are provided with a fixing device that fixes unfixed toner onto paper. In the device, a fixing roll, a pressure roll for pressing the paper against the fixing roll, and a paper fixing roll A separation claw for separating from the thermocouple, a thermistor for controlling temperature, and the like are provided.

  Such a fixing roll usually has a fluororesin layer such as PTFE (tetrafluoroethylene resin) or PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) on the surface of a metal core such as aluminum or iron. It is provided as a release layer.

However, in the fluororesin-coated fixing roll as described above, the fluororesin coating film is torn due to high-temperature heating in the fixing device or wear due to conveyance of the recording paper, and the unfixed toner image on the recording paper becomes the core metal surface of the fixing roll In some cases, the recording paper roll may be wound around the roll due to the toner contamination.
Further, the toner stain on the fixing roll is transferred onto the recording paper to be sent next, and an offset phenomenon may occur. In the conventional fixing roll in which the core metal surface is coated with a fluororesin, There were major problems in durability.

  In addition, since fluororesin has essentially no adhesion to the core metal surface composed of aluminum, iron, etc., complicated pretreatment such as roughening the core metal surface and applying primer is required prior to fluororesin coating. Therefore, the formation of the fluororesin film on the surface of the metal core has a large number of steps and has been a major bottleneck in cost reduction.

  In order to solve the problems of such a fluororesin-coated roll, a nickel plating layer in which release layer fine particles such as boron nitride and PTFE particles (tetrafluoroethylene resin particles) are dispersed is separated as a new surface layer material. A fixing member used as a mold layer has been proposed (see, for example, Patent Document 1 or 2).

Such a releasable composite metal plating layer is first excellent in durability as compared with a fluororesin, and the life of the fixing roll and the fixing device can be extended.
In addition, since heat transfer is higher than that of fluororesin and heat energy can be used efficiently, it is possible to save energy and increase the speed of the fixing device. Furthermore, in order to form this composite metal plating layer on the cored bar, it is only necessary to plate directly on the surface of the degreased / washed cored bar, and good adhesion can be achieved without applying a primer between the cored bar surface and the plating layer. Can be expected, and the production process can be simplified compared to fluororesin-coated rolls.

However, the fixing roll coated with such a releasable composite metal plating layer is insufficient in releasability with toner, and a large amount of releasable oil or Actual use was difficult unless used together with a cleaning system.
JP-A-61-205966 JP-A-6-27851

  The present invention maintains a high abrasion resistance and thermal efficiency, has a good releasability, and can stably fix a good image, and a stable fixed image can be obtained using the fixing roll. It is an object of the present invention to provide an obtained fixing device and an image forming device capable of forming a good image quality using the fixing roll.

The above object is achieved by the present invention below. That is, the present invention
<1> A fixing roll provided with an electroless nickel plating layer in which fluororesin particles are dispersed as a surface layer on a cylindrical metal core, the surface of the electroless nickel plating layer being roughened, A fixing roll having a thickness Rz of 1 μm or more and 6 μm or less.

  <2> The fixing roll according to <1>, wherein the roughening is performed by providing a circumferential narrow groove on the surface of the electroless nickel plating layer.

  <3> The fixing roll according to <2>, wherein a groove interval of the fine grooves is 50 μm or more and 400 μm or less.

  <4> The fine groove is provided on the surface of the electroless nickel plating layer by forming the electroless nickel plating layer after providing the fine groove in the circumferential direction on the surface of the cylindrical core metal. The fixing roll according to <2> or <3>.

  <5> A fixing device including a fixing roll and a pressure member disposed to face the fixing roll, wherein the fixing roll is any one of the items <1> to <4>. The fixing device is characterized by using a fixing roll.

  <6> The fixing device according to <5>, further including a release agent supply device to the surface of the fixing roll.

<7> The storage viscoelasticity G ′ at 180 ° C. is 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa at least, including at least a binder resin, a colorant, and a release agent, and 180 An image forming apparatus comprising: a toner having an adhesion force to an aluminum substrate at 50 ° C. of 50 N / m or less, and further comprising the fixing device according to <5>.

  According to the present invention, a fixing roll that maintains high wear resistance and thermal efficiency, has a good releasability, and can stably fix a good image, and a stable fixing using the fixing roll. It is possible to provide a fixing device capable of obtaining an image and an image forming device capable of forming a good image quality using the fixing roll.

In the fixing roll of the present invention, the surface of an electroless nickel plating layer (hereinafter simply referred to as “plating layer”) in which fluororesin particles are dispersed is roughened, and the surface roughness Rz is 1 μm or more and 6 μm or less. It is characterized by being.
When the surface roughness Rz is less than 1 μm, there is no effect of improving the releasability due to the roughening, and it becomes impossible to prevent the roll surface from being offset and the recording paper wound. On the other hand, when the surface roughness Rz exceeds 6.0 μm, the fixing roll initially exhibits good releasability, but the surface is too rough and the surface of the roll is poorly cleaned. When the toner is continuously used, minute toner stains are accumulated on the roll surface, and offset and winding of the recording paper around the roll surface occur.
The surface roughness Rz is more preferably 1.5 μm or more and 5.0 μm or less, and particularly preferably 1.5 μm or more and 4.0 μm or less.

  The surface roughness Rz in the present invention is the surface roughness specified in JIS-B0601 (1994), and the measurement is performed on the roll surface under the conditions of a measurement length of 2.5 mm and a cutoff value of 0.25 mm. On the other hand, the measuring needle of the roughness meter can be scanned in the axial direction. In the present invention, Surfcom 1400A (manufactured by Tokyo Seimitsu Co., Ltd.) was used as the roughness meter.

  The surface of the plating layer is in the range of the surface roughness Rz by being roughened. A method for roughening the surface of the plating layer is not particularly limited, but a method of providing a circumferential cutting groove (fine groove) by machining and a method of blasting with glass beads are representative. It is considered a technique.

  Further, although the surface is roughened as described above, the surface of the plating layer is separated from the toner by roughening the surface in both the method of providing the surface fine grooves and the method of blasting. In the case of a blasted fixing roll, the surface property (surface irregularity) may appear in the image when fixing an unfixed toner image. From the viewpoint of image quality, A method of providing a narrow groove on the surface is more preferable.

The interval between the narrow grooves provided on the surface is preferably 50 μm or more and 400 μm or less. If the interval between the narrow grooves is outside this range, less than 50 μm or wider than 400 μm, toner contamination may occur on the surface of the fixing roll, and offset or winding of the recording paper around the roll surface may occur.
The interval between the narrow grooves is preferably 50 μm or more and 300 μm or less, and particularly preferably 50 μm or more and 250 μm or less.

  The width of the narrow groove is preferably 10 μm or more and 200 μm or less, more preferably 30 μm or more and 150 μm or less from the viewpoint of processability and prevention of toner contamination.

In addition, from the viewpoint of obtaining good releasability, it is preferable that both the interval and the groove width of the fine grooves are controlled within the above ranges, and further, the interval is 50 μm or more and 250 μm or less and the groove width is 30 μm. It is preferable to use a narrow groove of 150 μm or less.
Moreover, it is preferable to provide the said fine groove at equal intervals in the plating layer surface whole region from a viewpoint of obtaining favorable mold release property.

Hereinafter, a fixing roll and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a fixing roll of the present invention, and FIG. 2 is an enlarged sectional view of a surface layer (electroless nickel plating layer) of the fixing roll.
The fixing roll shown in FIG. 1 has a surface layer 1 formed on a cylindrical cored bar 3. As shown in FIG. 2, the surface layer 1 contains a nickel-phosphate alloy 5 from within its thickness. The fluororesin particles 2 are dispersed three-dimensionally over the surface. In addition, narrow grooves 4 in the circumferential direction, which is a preferred embodiment of the present invention, are formed on the entire surface of the surface layer 1.

  In addition, as the said cylindrical core metal 3, a conventionally well-known thing can be selected suitably and can be used, Specifically, the core metal formed with stainless steel, iron, aluminum, etc. is mentioned.

(Electroless nickel plating layer)
The surface layer 1 of the fixing roll of the present invention is manufactured by an electroless nickel plating method described below. That is, as shown in FIG. 3, a cylindrical cored bar 3 is immersed in a plating tank 6 filled with a plating solution 7 for electroless nickel plating in which fluororesin particles 2 are dispersed, and the self-catalytic action causes the figure to appear. 4, nickel 5 is deposited on the surface of the core metal 3, and at the same time, the fluororesin particles 2 suspended in the plating solution 7 are deposited on the coating 8 formed on the surface of the core metal 3 by the deposition of nickel 5. Let it be captured. This phenomenon is called co-folding.
In this way, by the co-folding phenomenon, a film 8 of nickel 5 in which the fluororesin particles 2 are dispersed from the surface to within the wall thickness is grown on the surface of the core metal 3, and when the desired thickness is reached, the core metal 3 is pulled up from the plating tank 6.

Specifically, the fluororesin particles 2 include PTFE (tetrafluoroethylene resin), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer). Polymer), ETFE (polyethylene-tetrafluoroethylene copolymer), PVDF (polyvinylidene fluoride), PCTFE (polychlorotrifluoride ethylene), PVF (vinyl fluoride), etc., among these, plating From the viewpoint of dispersibility in the bath and heat resistance, PTFE (tetrafluoroethylene resin) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) are more preferable. The volume average particle size of the fluororesin particles 2 used is preferably 10 μm or less, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 2.0 μm.
In addition, as a measuring method of the said volume average particle diameter, it can measure by normal methods, such as a laser diffraction type particle size distribution analyzer.
Furthermore, the content of the fluororesin particles in the plating film can be contained up to 30% by mass relative to the metal, but is preferably selected from the range of 1.5 to 25% by mass, more preferably. Is particularly preferably 5.0 to 20% by mass.

  The thickness of the plating layer 1 is preferably 5 to 30 μm, more preferably 10 to 20 μm, from the viewpoint of durability required as a fixing member and heat transfer to the recording paper.

  The electroless nickel plating layer formed in this way has a structure in which the fluororesin particles 2 are dispersed in nickel (nickel-phosphate alloy) 5 and immediately after plating, phosphoric acid in the nickel alloy. It is known that the content is high and the surface hardness and wear resistance are low. Therefore, it is generally performed that the plated layer is heat-treated at a temperature range of 350 to 400 ° C. for 10 to 30 minutes to reduce the phosphoric acid content in the alloy and improve the surface hardness and wear resistance.

(Thin groove forming method)
As a method of processing the circumferential narrow groove on the surface of the plating layer, a method of machining (lathe processing) can be mentioned, and any method such as cutting or grinding may be used as necessary.
In addition, it is more preferable to process the fine grooves in advance on the surface of the core metal as a base before the plating process, instead of processing after the plating layer is formed. The electroless nickel plating layer in the present invention has the property that the base shape is transferred to some extent. If a fine groove is provided on the surface of the metal core before plating, the shape is transferred, and the fine groove is formed on the surface of the plating layer. Will be provided. Further, as described above, since the plated layer is extremely excellent in durability, that is, has a high hardness, it is easier to form the fine groove in the core metal than to form the fine groove in the plated layer itself.
Further, when a fine groove is formed on the surface of the plating layer by the above method, the roughness Rz of the surface of the plating layer tends to be larger than the roughness Rz of the surface of the core metal on which the fine groove is formed. In other words, the plating layer tends to be formed with a thicker film thickness at the peak portion than at the groove valley portion, and the narrow groove formed on the core metal surface can be small (shallow). It is easier to form a narrow groove in the core in advance. From the above, the method of forming a narrow groove in advance on the surface of the metal core can simplify the production of the fixing roll of the present invention.

  Furthermore, the method of forming a narrow groove on the surface of the metal core in advance damages the surface of the plated layer directly compared to a method of forming a plated layer on the surface of a smooth metal core and then processing the surface of the plating layer to obtain a fine groove. Therefore, it is effective for preventing the occurrence of roll contamination due to toner adhesion.

  The circumferential narrow grooves do not need to be provided completely in parallel with the rotation direction of the fixing roll. For example, the cutting depth and feed amount of the tool during lathe machining are constant with respect to the core metal (or plating layer) surface. Thus, it may be possible to devise processing such as continuously forming spiral narrow grooves.

(Image forming apparatus and fixing apparatus)
The fixing roll of the present invention described above is used in a fixing device that fixes an unfixed toner image formed on a recording medium in an image forming apparatus. As the fixing device, oil is supplied to the surface of the fixing roll. It is preferable to have an oil application device. The fixing roll of the present invention can exert its function more remarkably by being supplied with oil.

Hereinafter, an embodiment in which the above-described fixing roll is used in an image forming apparatus and a fixing apparatus will be described.
FIG. 5 is a schematic view showing an example of an image forming apparatus using the fixing roll of the present invention. An image forming apparatus 100 illustrated in FIG. 5 includes an image carrier 101, a charger 102, a writing device 103 for forming an electrostatic latent image, black (K), yellow (Y), magenta (M), cyan (C ) Developing devices 104A, 104B, 104C, 104D, neutralizing lamp 105, cleaning device 106, intermediate transfer member 107, transfer roll 108, fixing roll 109, pressure roll 110, and oil application device 112. Consists of.

The image formation using the image forming apparatus 100 will be described. First, as the image carrier 101 rotates in the direction of arrow A, the surface of the image carrier 101 is uniformly charged by the non-contact type charger 102. An electrostatic latent image corresponding to image information of each color is formed on the uniformly charged surface of the image carrier 101 by the writing device 103, and the electrostatic latent image is formed on the surface of the image carrier 101 on which the electrostatic latent image is formed. A toner image is formed by supplying toner from the developing units 104A, 104B, 104C, and 104D in accordance with the color information of the latent image.
Next, the toner image formed on the surface of the image carrier 101 is applied with a voltage between the image carrier 101 and the intermediate transfer member 107 by a power source (not shown), whereby the image transfer member 101 and the intermediate transfer member are transferred. The image is transferred to the surface of the intermediate transfer body 107 at the contact portion with the body 107.

The surface of the image carrier 101 on which the toner image has been transferred to the intermediate transfer body 107 is neutralized by irradiating light from a neutralization lamp 108, and the toner remaining on the surface is removed by a cleaning blade of a cleaning device 106. Is done.
By repeating the above process for each color, a toner image of each color is laminated on the surface of the intermediate transfer member 107 so as to correspond to the image information.
It should be noted that the transfer roll 108 is not in contact with the intermediate transfer member 107 during the above-described process, and the toner image of all colors is laminated and formed on the surface of the intermediate transfer member 107. At the time of transfer, it is brought into contact with the intermediate transfer member 107.

  The toner image laminated on the surface of the intermediate transfer member 107 in this manner moves to the contact portion between the intermediate transfer member 107 and the transfer roll 108 as the intermediate transfer member 107 rotates in the arrow B direction. At this time, the recording medium 111 is inserted through the contact portion in the direction of arrow N by a paper transport roll (not shown), and the surface of the intermediate transfer body 107 is applied by the voltage applied between the intermediate transfer body 107 and the transfer roll 108. The laminated toner images are collectively transferred to the surface of the recording medium 111 at the contact portion.

  The recording medium 111 having the toner image transferred onto the surface in this way is conveyed to a fixing device including the fixing roll 109, the pressure roll 110, and the oil application device 112, and the toner image is fixed on the surface of the recording medium 111. As a result, an image is formed.

Next, the fixing device will be described in more detail. FIG. 6 is a schematic view showing an example of the fixing device of the present invention.
6 includes a fixing roll 109 composed of a core metal 109A, a surface layer 109B and a heating source (halogen lamp) 109C, a pressure roll 110 composed of a core metal 110A and an elastic layer 110B, and a web-type separation device. It comprises a mold oil applicator 112 and a temperature sensor 113, and the fixing roll 109 and the pressure roll 110 are in pressure contact to form a nip portion. Further, the recording medium 111 may have a nail (finger) for peeling the recording medium 111 from the fixing roller 109.

  As described above, the recording medium 111 on which the unfixed toner image M is formed is conveyed to the nip portion in the direction of the arrow N, and when the recording medium 111 passes through the nip portion, the surface thereof is changed by the built-in heating source 109C. Heated by the heated fixing roll 109, a fixed toner image T is formed on the recording medium 111.

Here, the application amount of the release agent is preferably 1.6 × 10 ^{−5 to} 8.0 × 10 ⁻⁴ mg / cmU. The coating amount of the release agent is preferably smaller from the viewpoint of the smoothness and gloss of the resulting image, and more than 8.0 × 10 ⁻⁴ mg / cmU (0.5 mg per A4 sheet). The image quality deteriorates due to the release agent remaining on the surface of the image after fixing, especially when transmitted light such as OHP is used, or the release agent adheres to the recording medium 111 and becomes solid. Problems such as sticking occur. Further, when the supply amount of the release agent is increased, the capacity of the tank for storing the release agent is increased, and there is a problem that the fixing device is enlarged.

  The supply amount of the release agent is measured as follows. That is, when a plain paper (typically, a copy paper manufactured by Fuji Xerox Co., Ltd., trade name J paper) used in a general copying machine is passed through a fixing roll 109 having a release agent supplied to the surface, the paper is placed on the plain paper. Mold release agent adheres. The release agent on the plain paper is extracted using a Soxhlet extractor. Hexane is used as the solvent. By quantifying the release agent contained in the hexane with an atomic absorption analyzer, the amount of the release agent adhering to the plain paper is quantified. This amount is defined as the supply amount of the release agent.

  The release agent to be used is not particularly limited, and examples thereof include liquid release agents such as heat-resistant oils such as dimethyl silicone oil, fluorine oil, fluorosilicone oil, and modified oils such as amino-modified silicone oil.

  As the release agent, high-performance but expensive fluorine oil, fluorosilicone oil, etc. can be used without any practical problems in terms of cost since the supply amount of the release agent is very small in the case of the above fixing device. sell.

  The method for supplying the release agent is not particularly limited, and examples thereof include a pad method impregnated with a liquid release agent, a web method, a roller method, and a non-contact shower method (spray method). Among these, the web method and the roller method are preferable from the viewpoint that the release agent can be supplied uniformly and the supply amount can be easily controlled. In order to supply the release agent uniformly to the entire fixing roll 109 by a shower method, it is necessary to use a separate blade or the like.

In the fixing device shown in FIG. 6, since the fixing roll of the present invention is used as the fixing roll 109 and the release oil is supplied from the release oil application device 112 to the surface of the fixing roll 109, the toner is very good for the toner. Releasability is shown.
In addition, when the fixing roll of the present invention provided with the above-described circumferential narrow grooves is used as the fixing roll 109, the oil supplied to the surface of the fixing roll 109 enters the narrow grooves and spreads along the narrow grooves. However, it will be held in the narrow groove for a long time. Due to the oil retaining action of the narrow groove, a constant amount of oil is always present on the surface of the fixing roll 109 even when the amount of oil applied from the release oil applying device 112 is small, and the fixing roll 109 has a stable release. Sex is secured. Accordingly, it is possible to provide a fixing device in which toner contamination on the fixing roll 109, winding of the recording medium 111, and occurrence of image offset are prevented, and a stable fixed image can be always obtained.

(toner)
In the image forming apparatus using the fixing roll of the present invention, it is preferable to use highly releasable toner from the viewpoint of further improving releasability. Specifically, the toner comprises at least a binder resin, a colorant, and a release agent, and the storage viscoelasticity G ′ at 180 ° C. is 5.0 × 10 ^{2 to} 1.0 × 10. is ^5, and adhesion to the aluminum substrate at 180 ° C. it is particularly preferable to use the toner is not more than 50 N / m.
Hereinafter, the toner will be described.

The adhesion force of the toner to the aluminum substrate can be measured using a universal tensile tester (manufactured by Toyo Seiki Seisakusho). First, toner is adjusted to a transfer medium of 4.5 g / m ² with a width of 10 mm and a width of 35 mm on plain paper as a recording medium and uniformly transferred, and the toner is fixed at a temperature of 180 ° C. using a heat fixing roll. After that, the plain paper on which the toner has been fixed is placed on an aluminum substrate, brought to 180 ° C. in a constant temperature bath, and the adhesion between the fixed image and the aluminum substrate is obtained with a universal tensile tester. Here, the plain paper may be paper that is generally used in an image forming apparatus, and examples thereof include L paper, P paper, and S paper (all manufactured by Fuji Xerox Co., Ltd.). Further, the aluminum substrate having a mirror surface is used. The closer the adhesion is to 0 N / m, the more preferable, but practically it is preferably 50 N / m or less, more preferably 30 N / m or less, and particularly preferably 15 N / m or less. When the adhesive force is 50 N / m or less, good releasability from the fixing roll can be obtained, and a high-quality image can be obtained.

The storage viscoelasticity G ′ of the toner is preferably 5 × 10 ² to 1 × 10 ⁵ Pa, more preferably 5 × 10 ^{2 to} 5 × 10 ⁴ Pa at 180 ° C. It is preferably 1 × 10 ³ to 1 × 10 ⁴ Pa. By being 5 × 10 ² Pa or more, there is an effect in preventing offset, while when it is 1 × 10 ⁵ Pa or less, good fixability is obtained. For measuring the viscoelasticity G ′, an ARES measuring apparatus manufactured by Rheometric Scientific was used. After the toner was molded into a tablet, it was set on a 25 mm diameter parallel plate, and the storage viscoelasticity G ′ at 180 ° C. was determined under the condition of angular velocity ω = 10 rad / sec.

  Moreover, it is preferable that the content rate of the said mold release agent is 5-40 mass%, 10-30 mass% is more preferable, and 15-25 mass% is especially preferable. If the content rate of a mold release agent is 5 mass% or more, sufficient mold release property can be ensured and it is effective in prevention of hot offset. On the other hand, if it is 40% by mass or less, the release agent is not exposed to the toner surface, and fluidity and chargeability can be obtained.

The relationship between the release agent content W and the storage viscoelasticity G ′ in the toner is preferably G ′ ≧ 0.875 × 10 ⁴ (100−W) / W (× 10 ³ Pa). If the relationship between the release agent content W and the storage viscoelasticity G ′ satisfies the above formula, the releasability from the fixing roll becomes better and the occurrence of hot offset can be prevented.

In the toner, it is preferable to contain inorganic or organic fine particles in the toner in order to control the storage viscoelasticity of the toner if necessary. Examples of the inorganic fine particles include metals and oxides thereof, nitrides, carbonates, nitrates, sulfates, and the like. Specific examples include silica, alumina, titanium compounds, and calcium carbonate. Examples of the organic fine particles include vinyl resins, polyesters, and silicones.
1-30 mass% is preferable, as for the quantity to contain, 1-20 mass% is more preferable, and 1-10 mass% is especially preferable. If the content is 1% by mass or more, the storage viscoelasticity can be easily controlled, and if it is 30% by mass or less, fine particles are not exposed on the toner surface, and fluidity and chargeability can be obtained.
Further, among the fine particles, the case of containing 1 to 20% by mass of inorganic fine particles is more preferable, and 1 to 10% by mass is particularly preferable. If inorganic fine particles are used, the viscoelasticity can be controlled more easily than organic fine particles, and the dispersibility in toner particles is good. If the content is 1% by mass or more, the storage viscoelasticity can be easily controlled, and if it is 20% by mass or less, the toner particles can be easily produced and the dispersion can be controlled. .
The particle diameter of the fine particles is preferably 5 to 200 nm, more preferably 10 to 100 nm, and particularly preferably 10 to 20 nm. If it is 5 nm or more, it is easy to disperse in the toner and aggregation between the fine particles hardly occurs, and if it is 200 nm or less, it is easy to control the dispersion state in the toner and there is an advantage that the exposure to the surface is small. is there.

  As for the volume average particle diameter of the toner, the volume average particle diameter D50 measured with a Coulter counter is preferably 4.0 to 10.0 μm. More preferably, it is 5.0-8.0 micrometers, Most preferably, it is 5.0-7.0 micrometers. If the thickness is 4.0 μm or more, it is possible to prevent the occurrence of cloud due to toner behavior. On the other hand, if it is 10.0 μm or less, a good quality image can be obtained.

The particle size was measured using a Coulter Counter TA-II type (manufactured by Beckman Coulter, Inc.), and a measurement sample (toner) in 2 ml of a 5% aqueous solution of a surfactant, preferably sodium alkylbenzenesulfonate, as a dispersant. Of 0.5 to 50 mg. This is added to 100-150 ml of electrolyte.
The electrolyte solution in which the measurement sample is suspended is subjected to a dispersion treatment with an ultrasonic disperser for about 1 minute, and the particle size distribution of particles of 2.0 to 60 μm is obtained using the Coulter counter TA-II type with an aperture diameter of 100 μm. Measure volume average distribution and number average distribution. The number of particles to be measured is 50,000. From these volume average distribution and number average distribution, the volume average particle diameter is obtained. In the particle size distribution, a cumulative distribution is drawn from the smaller diameter side for each of the divided particle size ranges (channels), and the particle size at 50% accumulation is defined as the volume average particle size D50.

In addition, the particle size distribution of the toner is the ratio of the cumulative 84% diameter (D84v) to the cumulative 16% diameter (D16v) (D84v / D16v) ^1/2 (GSDv: volume average particle size) measured by a Coulter counter. The distribution index is preferably 1.30 or less and the number particle size (D84p / D16p) ^1/2 (GSDp: number average particle size distribution index) is preferably 1.40 or less. If GSDv is 1.30 or less and GSDp is 1.40 or less, a high-quality image can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, these examples do not limit the present invention. In the following, “part” and “%” represent “part by mass” and “% by mass”.

<Preparation of developer>
[Preparation of resin particle dispersion A]
Styrene (manufactured by Wako Pure Chemical Industries) 306 parts n-butyl acrylate (manufactured by Wako Pure Chemical Industries) 94 parts β-carboxyethyl acrylate (manufactured by Rhodia Nikka) 12 parts 1,10-decanediol diacrylate (manufactured by Shin-Nakamura Chemical) 3 parts Dodecanethiol (manufactured by Wako Pure Chemical Industries) 21.4 parts A solution of 4 parts of the anionic surfactant Dowfax (manufactured by Dow Chemical Co.) dissolved in 570 parts of ion-exchanged water is added to the solution obtained by mixing and dissolving the above components. The mixture was dispersed and emulsified in the flask, slowly stirred and mixed for 10 minutes, and then 50 parts of ion-exchanged water in which 6 parts of ammonium persulfate had been dissolved was added. While stirring the solution in the oil bath until it reaches 70 ° C., the emulsion polymerization is continued for 5 hours, and the anionic resin particle content To obtain a liquid A. The center particle diameter of the resin fine particles in the resin particle dispersion A was 235 nm, the solid content was 42.9%, and the weight average molecular weight Mw was 35500.

[Preparation of resin particle dispersion B]
Styrene (made by Wako Pure Chemical Industries) 280 parts n-butyl acrylate (made by Wako Pure Chemical Industries) 120 parts β-carboxyethyl acrylate (manufactured by Rhodia Nikka Co., Ltd.) 12 parts An ion exchange solution in which 1.5 parts of Dow Chemical Company is dissolved in 550 parts of ion-exchanged water is added, dispersed and emulsified in a flask, and slowly stirred and mixed for 10 minutes. 50 parts of water was added, and the flask was sufficiently purged with nitrogen. Then, the solution in the flask was heated with stirring in an oil bath to 70 ° C., and emulsion polymerization was continued for 5 hours. Resin particle dispersion B was obtained. The center particle diameter of the resin fine particles in the resin particle dispersion B was 180 nm, the solid content was 42.3%, the weight average molecular weight Mw was 797,000, the number average molecular weight was Mn266600, and the glass transition temperature was 53.5 ° C.

[Preparation of Colorant Particle Dispersion A]
Carbon black R660R (manufactured by Cabot) 30 parts Anionic surfactant Newlex R (manufactured by Nippon Oil & Fats) 2 parts ion-exchanged water 220 parts The above ingredients are mixed and pre-dispersed for 10 minutes with a homogenizer (Ultra Turrax: made by IKA) After that, dispersion processing was performed for 15 minutes at a pressure of 245 mPa using an optimizer (counter collision type wet pulverizer: manufactured by Sugino Machine) to obtain a colorant particle dispersion A having a center diameter of 333 nm.

[Preparation of release agent particle dispersion A]
45 parts of polyethylene wax PW725
(Melting point 104 ° C: Toyo Petrolite)
Cationic surfactant Neogen RK (Daiichi Kogyo Seiyaku Co., Ltd.) 5 parts Ion-exchanged water 200 parts The above ingredients were mixed, heated to 95 ° C., and pre-dispersed for 10 minutes with a homogenizer (Ultra Turrax: manufactured by IKA). Using a gorin homogenizer (pressure jet pulverizer: manufactured by Gorin), a dispersion treatment was performed to obtain a release agent particle dispersion A having a center diameter of 177 nm.

(Production of toner)
90 parts of the above resin particle dispersion A 150 parts of the above resin particle dispersion B 60 parts of the colorant particle dispersion A 60 parts of the release agent particle dispersion A 100 parts The above components are homogenizer (Ultra Turrax: IKA) in a round stainless steel flask. Then, 0.3 parts of polyaluminum chloride in this solution was added to produce core aggregated particles, which were further dispersed with an ultra turrax for 5 minutes. Then, while stirring the inside of the flask with a heated oil bath, the temperature was raised to 51 ° C., held at 51 ° C. for 1 hour to form core aggregated particles, and then 130 parts of resin particle dispersion A was added to form core / shell aggregated particles. Was made. Thereafter, 0.5N sodium hydroxide aqueous solution is added to adjust the pH of the solution to 6, then the temperature is raised to 95 ° C., pH is adjusted to 4 with 0.5N nitric acid, and the mixture is held at 96 ° C. for 5 hours. Then, it was cooled and neutralized with alkali, filtered, washed with water, separated into solid and liquid, and further vacuum dried to obtain a black toner.

  The toner obtained from the above was measured with a Coulter counter TA-II type (manufactured by Coulter, Inc.) by the above method, and the toner volume average particle size D50, volume average particle size distribution index GSDv, and number average particle size distribution index GSDp As a result, D50 was 7.0 μm, GSDv was 1.24, and GSDp was 1.26.

(Addition of external additives and preparation of developer)
To 50 parts of the toner, 3.5 parts of hydrophobic silica (TS720: manufactured by Cabot) was added as an external additive, and blended in a sample mill. Next, a toner obtained by adding an external additive to a ferrite carrier coated with 1% ferrite polymethyl methacrylate (PMMA) on the surface of ferrite particles having an average particle diameter of 50 μm is adjusted so that the toner concentration becomes 5%. A developer was prepared by mixing.

Adjust the toner loading amount to 4.5 g / m ² on a rectangular paper 10 mm long and 35 mm wide, and evenly place it, fix the toner at a temperature of 180 ° C., and then put it on a universal tensile tester on an aluminum substrate. The paper on which the toner was fixed was placed, and the temperature was set to 180 ° C. in a constant temperature bath, and the adhesion force between the fixed image and the aluminum substrate was determined by a universal tensile tester. The adhesion force was 19.0 N / m.
Further, the storage viscoelasticity G ′ measured by the above-described method was 11.5 × 10 ³ Pa.

<Manufacture of fixing roll>
Next, production of the fixing rolls of Examples 1 to 11 and Comparative Examples 1 to 4 will be described.
In addition, the surface roughness Rz described in the content described below is a roughness meter (manufactured by Tokyo Seimitsu Co., Ltd., trade name: Surfcom) on the roll surface under the conditions of a measurement length of 2.5 mm and a cutoff value of 0.25 mm. 1400A) is measured by scanning the measuring needle in the axial direction and verifying it.

(Example 1 to Example 4)
The surface of the aluminum pipe (metal cylindrical body) with a diameter of 35mm and a thickness of 2.0mm is swung with the lathe processing conditions to form the circumferential spiral grooves shown in Table 1. The surface roughness Rz and the distance between the grooves are Four different types of mandrel were produced. Next, the surface of the metal core is subjected to electroless plating with an electroless nickel plating bath (trade name “Kaniflon A”, manufactured by Nihon Kanisen Co., Ltd.) in which PTFE particles are dispersed in advance to form nickel and PTFE particles. A plating film having a thickness of 10 μm was formed. Thereafter, the aluminum pipe was put into a badge furnace, and heat treatment was performed at 400 ° C. for 30 minutes, whereby the phosphoric acid component and the surfactant in the plating film were decomposed to form a hard plating film. After finishing the plating process, predetermined molding processing for fitting a drive gear or the like to both ends of the pipe was performed, and four types of fixing rolls having different surface roughness Rz were produced. Table 1 shows the characteristics of these transfer rolls.

The contact angle of water and silicon oil on the surface of each fixing roll was measured using a contact angle meter (trade name: CA-X roll type contact angle meter, manufactured by Kyowa Interface Science Co., Ltd.) as a measuring device. % Indoors.

(Comparative Example 1)
The surface of the aluminum pipe having a diameter of 35 mm and a thickness of 2.0 mm was subjected to a finishing process with a surface roughness Rz of 0.5 μm without performing a narrow groove process with a lathe.
Next, a plating film having a thickness of 10 μm formed of nickel and PTFE particles is formed on the surface of the metal core using a plating bath similar to that in Example 1, and then a predetermined gear for fitting a drive gear or the like to both ends of the pipe. A fixing roll having a smooth surface with a surface roughness of Rz 0.7 μm was produced by molding. The characteristics of the fixing roll of Comparative Example 1 are shown in Table 1 as in Example 1.

(Comparative Example 2)
On the surface of an aluminum pipe having a diameter of 35 mm and a thickness of 2.0 mm, a lathe having a Rz of 5 μm was performed to form a circumferential spiral groove. Next, a plating film having a thickness of 15 μm formed of nickel and PTFE particles is formed on the surface of the metal core using the same plating bath as in Example 1, and then a predetermined gear for fitting a drive gear or the like to both ends of the pipe. A fixing roll having a surface with a surface roughness Rz of 8.0 μm was formed by molding. The characteristics of the fixing roll of Comparative Example 2 are shown in Table 1 as in Example 1.

(Example 5)
The surface of the aluminum pipe having a diameter of 35 mm and a thickness of 2.0 mm was subjected to a finishing process with a surface roughness Rz of 0.5 μm without performing a narrow groove process with a lathe. Next, a plating film having a thickness of 10 μm formed of nickel and PTFE particles is formed on the surface of the metal core using the same plating bath as in Example 1, and then the surface roughness Rz is 3.0 μm by blasting. A surface was formed. Thereafter, a predetermined molding process for fitting a drive gear or the like to both ends of the pipe was performed, and a fixing roll having a blast surface with a surface roughness Rz of 3.0 μm was produced. The characteristics of the fixing roll of Example 5 are shown in Table 1 as in Example 1.

(Example 6 to Example 10)
The surface of an aluminum pipe with a diameter of 35 mm and a thickness of 2.0 mm is subjected to lathe machining conditions to form circumferential spiral grooves as shown in Table 1, with a surface roughness Rz of 2.0 μm and a narrow groove interval. Four different types of mandrel were produced. Next, a plating film having a thickness of 10 μm formed of nickel and PTFE particles is formed on the surface of the metal core using a plating bath similar to that in Example 1, and then a predetermined gear for fitting a drive gear or the like to both ends of the pipe. Molding processing was performed, and five types of fixing rolls having surfaces with a surface roughness Rz of 3.0 μm and different groove intervals were produced. The characteristics of the fixing rolls of Examples 6 to 10 are shown in Table 1 as in Example 1.

(Example 11)
The surface of the aluminum pipe having a diameter of 35 mm and a thickness of 2.0 mm was subjected to a finishing process with a surface roughness Rz of 0.5 μm without performing a narrow groove process with a lathe. Next, a plating film having a thickness of 10 μm formed of nickel and PTFE particles is formed on the surface of the metal core using the same plating bath as in Example 1, and then the surface roughness Rz is set to 4.0 μm by lathe processing. Directional spiral grooves were formed. Thereafter, a predetermined molding process for fitting a drive gear or the like to both ends of the pipe was performed, and a fixing roll having a fine groove surface with a surface roughness Rz of 4.0 μm was produced. The characteristics of the fixing roll of Example 11 are shown in Table 1 as in Example 1.

(Comparative Example 3)
The surface of the aluminum pipe with a diameter of 35 mm and a thickness of 2.0 mm is subjected to surface treatment, primer application, and other pretreatment, followed by powder coating with PFA resin powder paint (trade name MP-10, manufactured by DuPont) and firing. The process and the circumferential polishing process were repeated to form a fluororesin layer having a surface roughness Rz of 2.0 μm and a thickness of 20 μm. Thereafter, a predetermined molding process for fitting a drive gear or the like to both ends of the pipe was performed, and a fixing roll having a surface roughness Rz of 2.0 μm and a thickness of 20 μm of a fluororesin surface was produced. The characteristics of the fixing roll of Comparative Example 3 are shown in Table 1 as in Example 1.

(Comparative Example 4)
A fixing roll having a fluororesin surface with a surface roughness Rz of 6.0 μm and a thickness of 20 μm was produced by changing the polishing conditions during formation of the fluororesin layer in the same materials and processes as in Comparative Example 3. The characteristics of the fixing roll of Comparative Example 4 are shown in Table 1 as in Example 1.

  Of the examples and comparative examples described above, Examples 1 to 11 and Comparative Examples 1 and 2 are electroless nickel plating baths in which PTFE particles are dispersed in advance (trade name “Kaniflon A”, manufactured by Nippon Kanisen). As shown in Table 1, the result was that the surface roughness Rz increased before and after the plating treatment, which is considered to be a characteristic of the plating bath used. However, the present invention is not limited.

(Incorporation into the fixing device)
The fixing rolls of Examples 1 to 11 and Comparative Examples 1 to 4 were attached to the two-roll fixing device shown in FIG. 6 and the NiP width was set to 7 mm and the process speed was set to 205 mm / sec. ) Was adjusted to 5/100 cc per A4 sheet.

(Experiment 1 Fixation latitude and Finger Mark survey)
Using the fixing device described above, S paper (Fuji Xerox, basis weight 56 g / m ² ) was used as the recording paper, and 10 unfixed solid images were continuously passed using the developer from the above to obtain a sample. The presence or absence of offset (Hot / Cold) was examined. This experiment was performed in the temperature range of 150 ° C. to 220 ° C. while changing the fixing temperature every 10 ° C. FIG. 7 shows the results obtained by collecting these experimental results for each fixing roll obtained from the above as fixing latitude (non-offset region).

  Next, in the sample of Experiment 1, the result of examining the presence or absence of a peeling mark (Finger Mark) is shown in FIG.

  As shown in FIGS. 7 and 8, the fixing rolls of Examples 1 to 11 having a roughened surface have a wider offset and finger mark non-occurrence area than that of Comparative Example 1 having a smooth surface, and are stable. It was confirmed that the fixing property was improved.

  Moreover, when Example 2 which shows surface roughness Rz comparable as the comparative example 3 coat | covered with the fluororesin surface and Example 4 which shows surface roughness Rz comparable as the comparative example 4 are each compared, offset and Finger It was confirmed that the non-marked area was uniformly low, and that the fixing roll of the present invention can be fixed at a low temperature and has high energy saving performance as compared with the prior art.

  In the sample of Experiment 1, with respect to the fixing roll (blast surface) of Example 5, all of the toner images fixed even in the region where no offset occurs have a satin-like surface roughness that does not cause a problem. From the viewpoint of quality, the superiority of the fixing rolls of Examples 1 to 4 and Examples 6 to 11 in which narrow grooves were formed was confirmed.

(Experiment 2 Maintainability of releasability)
Next, for each of the fixing rolls of Examples 1 to 11 and Comparative Examples 1 to 4, using the above-described fixing device, the roll surface control temperature was set to 190 ° C., and then P paper (Fuji Xerox) was used as the recording paper. Table Ltd., using the basis weight of 64 g / m ^2), using a developer obtained from the passed through 10000 unfixed solid image, the result of confirming the winding of the toner adhering amount and the recording sheet of the fixing roll surface It is shown in 1.

  As a result, in the fixing rolls of Examples 1 to 11 in which the surface roughness Rz is 1 μm or more and 6 μm or less, the toner adheres more than the fixing rolls of Comparative Examples 1 and 2 in which the surface roughness Rz is outside the above range. It was confirmed that the winding of the recording paper could be suppressed.

(Experiment 3 Investigation of wear resistance of surface layer)
Next, after setting the roll surface control temperature to 190 ° C. for each of the fixing rolls of Example 2 and Comparative Example 3 having a wide fixing latitude in the above-described Examples and Comparative Examples, using the fixing device described above. Then, P paper (Fuji Xerox, basis weight 64 g / m ² ) was used as the recording paper, and after passing 500,000 blank papers, the wear on the surface of the fixing roll due to the paper edge was measured. As a result, in the fixing roll of Comparative Example 3, a level difference of about 1.5 μm was observed, but in the fixing roll of Example 2, the level difference of 0.5 μm or less was accommodated, and the durability of the composite nickel plating layer was confirmed. It was.

2 is a perspective view of an embodiment of a fixing roll of the present invention. FIG. FIG. 2 is an enlarged cross-sectional view of a surface layer in the fixing roll illustrated in FIG. 1. It is explanatory drawing which shows the method of forming an electroless nickel plating layer on the cylindrical core metal surface which concerns on this invention. It is an enlarged view of the cylindrical cored bar vicinity of FIG. 1 is a schematic configuration diagram of an image forming apparatus using a fixing roll of the present invention. 1 is a schematic configuration diagram of a fixing device using a fixing roll of the present invention. It is a graph which shows the test result of the fixing latitude (image offset non-occurrence | production area | region) in an Example. It is a graph which shows the test result of the Finger Mark non-occurrence | production area | region in an Example.

Explanation of symbols

1 Surface layer (electroless nickel plating layer)
2 Fluororesin particles 3 Cylindrical core 4 Narrow groove 5 Nickel (Nickel-phosphate alloy)
DESCRIPTION OF SYMBOLS 6 Plating tank 7 Plating solution 8 Film | membrane 100 Image forming apparatus 101 Image carrier 102 Charger 103 Writing apparatus 104A, 104B, 104C, 104D Developer 105 Discharge lamp 106 Cleaning apparatus 107 Intermediate transfer body 108 Transfer roll 109 Fixing roll 109A Fixing roll Core 109B Fixing roll surface layer 109C Heat source (halogen lamp)
DESCRIPTION OF SYMBOLS 110 Pressure roll 110A Pressure roll mandrel 110B Pressure roll elastic layer 111 Recording paper 112 Release oil coating apparatus (web system)
113 Temperature sensor M Unfixed toner image T Fixed toner image

Claims (3)

  A fixing roll provided with an electroless nickel plating layer in which fluororesin particles are dispersed as a surface layer on a cylindrical metal core, wherein a roughness Rz of the surface of the electroless nickel plating layer is 1 μm or more and 6 μm or less. A fixing roll.   A fixing device comprising: a fixing roll; and a pressure member disposed to face the fixing roll, wherein the fixing roll according to claim 1 is used as the fixing roll. apparatus. Aluminum containing at least a binder resin, a colorant, and a release agent, having a storage viscoelasticity G ′ at 180 ° C. of 5.0 × 10 ^{2 to} 1.0 × 10 ⁵ Pa, and 180 ° C. An image forming apparatus comprising: a toner having an adhesion force to a substrate of 50 N / m or less, and further comprising the fixing device according to claim 2.

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