Solid lubricant, image forming apparatus, and method for manufacturing image forming apparatus

Abstract

To provide a solid lubricant, an image forming apparatus, and a method for manufacturing an image forming apparatus in which cracking, chipping, and fissuring are unlikely to occur during manufacturing and in which the amount of wear during use in the image forming apparatus is small.SOLUTION: A solid lubricant according to the present invention, which is applied to a surface of an image carrier of an image forming apparatus employing an electrophotographic method to form a coating on the surface of the image carrier, comprises a higher fatty acid zinc (a) and a higher fatty acid metal salt (b) including a metal salt other than zinc. A metal species contained in the higher fatty acid metal salt (b) is one or more selected from metal species belonging to Group 1 elements, Group 2 elements, and Group 13 elements, and a value obtained by dividing a measured value of a spectral reflectance spectrum at a wavelength of 500 nm by a measured value of a spectral reflectance spectrum at a wavelength of 700 nm for the solid lubricant is 2.2-4.8.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a solid lubricant, an image forming apparatus, and a method for manufacturing an image forming apparatus. [Background technology]

[0002] Conventionally, in electrophotographic image forming apparatuses, residual toner and other deposits adhering to the surface of an image carrier (e.g., a photosensitive drum, an intermediate transfer body, etc.) on which a toner image is formed are removed (cleaned). Furthermore, in order to improve the cleaning performance of the image carrier, a solid lubricant (hereinafter sometimes simply referred to as "lubricant") is applied to the surface of the image carrier using a brush. Technologies related to lubricants have been proposed in Patent Documents 1 to 4, for example.

[0003] Patent Document 1 proposes a molded product of higher fatty acid zinc salts, which is obtained by cooling and solidifying a heated melt of a raw material containing higher fatty acid zinc salts and having a total amount of alkali metals of Group I of the periodic table and alkaline earth metals of Group II of the periodic table of 0.01% by mass or more and 0.12% by mass or less. Patent Document 2 proposes a molded product of higher fatty acid zinc salts, which is obtained by cooling and solidifying a heated melt of a raw material containing higher fatty acid zinc salts and in which the total amount of alkali metals of Group I of the periodic table and alkaline earth metals of Group II of the periodic table is more than 0 mass % and 0.12 mass % or less.

[0004] Patent Document 3 proposes a molded product of higher fatty acid zinc block, which is obtained by cooling and solidifying a heated melt of a composition containing: (A) 100 parts by mass of high-purity higher fatty acid zinc having a purity of 99.8% or more; and (B) 0.1 to 1.0 parts by mass, in terms of metal, of at least one compound selected from lower fatty acid salts, higher fatty acid salts, and inorganic carbonates containing an alkali metal of Group I of the periodic table or an alkaline earth metal of Group II of the periodic table. Patent Document 4 describes a higher fatty acid metal salt block characterized by containing 0.01 to 10 parts by weight of an additive higher fatty acid metal salt represented by a predetermined general formula (II) and containing a Group 1, Group 2, Group 12, or Group 13 element as the metal, per 100 parts by weight of a base higher fatty acid metal soap represented by a predetermined general formula (I) and containing a Group 2, Group 12, or Group 13 element as the metal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-70552 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-189557 [Patent Document 3] Japanese Patent Application Laid-Open No. 2007-77386 [Patent Document 4] Japanese Patent Application Laid-Open No. 2009-179761 Summary of the Invention [Problem to be solved by the invention]

[0006] Advances in image forming device technology have led to increasingly stringent demands for higher speeds, smaller sizes, higher durability, and higher reliability for image forming devices. As image forming devices become faster, the rotation speed of the application brush that applies lubricant to the image carrier increases, resulting in a faster consumption of the lubricant. To ensure a stable supply of lubricant to the image carrier over a long period of time, a lubricant that wears down less yet maintains the same size as conventional lubricants is required. Through investigations, the present inventors have found that there is room for improvement in the prior art, including Patent Documents 1 to 4, in terms of making cracks, chips, and fissures less likely to occur during manufacturing and reducing the amount of wear when used in an image forming device.

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a solid lubricant that is less likely to crack, chip, or break during manufacturing and that is less likely to be worn away when used in an image forming apparatus, an image forming apparatus, and a method for manufacturing an image forming apparatus. [Means for solving the problem]

[0008] That is, the above-mentioned problems of the present invention are solved by the following means. [1] A solid lubricant for application to the surface of an image carrier of an electrophotographic image forming apparatus to form a coating on the surface of the image carrier, the solid lubricant comprising (a) a higher fatty acid zinc salt and (b) a higher fatty acid metal salt containing a salt of a metal other than zinc, wherein the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements, and wherein the value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less.

[0009] [2] The solid lubricant according to [1], characterized in that the amount of the higher fatty acid metal salt (b) is 0.25 parts by mass or more and 10 parts by mass or less per 100 parts by mass of the higher fatty acid zinc salt (a).

[0010] [3] The solid lubricant according to [1], wherein the higher fatty acid in the higher fatty acid zinc salt (a) has at least one saturated fatty acid.

[0011] [4] The solid lubricant according to [1], wherein the higher fatty acid in the higher fatty acid metal salt (b) has at least one saturated fatty acid.

[0012] [5] An image forming apparatus comprising: an electrophotographic image carrier; and a coating forming means for scraping a solid lubricant and applying it to the surface of the image carrier to form a coating of the solid lubricant, wherein the solid lubricant comprises (a) a higher fatty acid zinc salt and (b) a higher fatty acid metal salt containing a metal salt other than zinc, and the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements, and the value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less.

[0013] [6] A method for producing the image forming device according to [5], comprising: a step of selecting a solid lubricant containing higher fatty acid zinc (a) and higher fatty acid metal salt (b) containing a salt of a metal other than zinc, wherein the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements, and wherein a value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less; and a step of incorporating the selected solid lubricant into the coating forming means. [Effects of the Invention]

[0014] The solid lubricant, image forming apparatus, and method for manufacturing an image forming apparatus according to the present invention are less likely to crack, chip, or break during manufacturing, and can reduce the amount of abrasion when used in an image forming apparatus. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view illustrating an example of a configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view illustrating an example of a configuration of a main part of an image forming apparatus according to an embodiment of the present invention. [Figure 3]10 is a flowchart illustrating a method for manufacturing an image forming apparatus according to the present embodiment. [Figure 4] 1 is an optical microscope image of Example 1. [Figure 5] 1 is an optical microscope image of Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a solid lubricant, an image forming apparatus, and a method for manufacturing an image forming apparatus according to one embodiment of the present invention will be described with reference to the accompanying drawings. Note that common components in the following description and drawings will be designated by the same reference numerals, and duplicated descriptions may be omitted. Furthermore, the present invention is not limited to the following embodiments.

[0017] [Solid lubricant] The solid lubricant (lubricant) according to this embodiment is applied to the surface of an image carrier in an electrophotographic image forming apparatus to form a coating on the surface of the image carrier. That is, this lubricant is formed into a solid shape, such as a rectangular parallelepiped, and is mounted in the image forming apparatus (described later) in this solid form, and is finely scraped off and applied to the surface of the image carrier during the image forming process. The image carrier is also called a photoreceptor.

[0018] This lubricant is composed of higher fatty acid zinc (a) and higher fatty acid metal salt (b) containing a metal salt other than zinc. This lubricant may contain unavoidable impurities as long as they do not interfere with the effects of the present invention. "Inevitable impurities" refer to impurities inevitably contained in the raw materials or impurities inevitably contained during production. Preferably, this lubricant is composed only of higher fatty acid zinc (a) and higher fatty acid metal salt (b) containing a metal salt other than zinc. When higher fatty acid zinc (a) is added to higher fatty acid metal salt (b), they are melted and mixed uniformly during production, and upon cooling, numerous stable crystal nuclei are obtained within which the higher fatty acid metal salt (b) is uniformly dispersed. This results in the formation of uniform crystals in the lubricant (see Figure 4 below), which is thought to result in less cracking, chipping, and cracking.

[0019] The metal species contained in the higher fatty acid metal salt (b) is preferably at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements. Examples of metal species belonging to Group 1 elements include lithium, sodium, potassium, rubidium, cesium, and francium. Of these, lithium, sodium, and potassium are preferably used as metal species belonging to Group 1 elements. Examples of metal species belonging to Group 2 elements include beryllium, magnesium, calcium, strontium, barium, and radium. Of these, magnesium, calcium, and barium are preferably used as metal species belonging to Group 2 elements. Examples of metal species belonging to Group 13 elements include aluminum, gallium, indium, and thallium, and among these, aluminum and gallium are preferably used as metal species belonging to Group 13 elements.

[0020] In this embodiment, the value obtained by dividing the measured spectral reflectance spectrum at a wavelength of 500 nm by the measured spectral reflectance spectrum at a wavelength of 700 nm for the lubricant is set to be 2.2 or more and 4.8 or less. Addition of higher fatty acid metal salt (b) increases the measured spectral reflectance spectrum at a wavelength of 500 nm and hardens the lubricant. Without the addition of higher fatty acid metal salt (b), the spectral reflectance spectrum at a wavelength of 500 nm does not increase, and the lubricant does not harden. When the value obtained by dividing the measured spectral reflectance spectrum at a wavelength of 500 nm by the measured spectral reflectance spectrum at a wavelength of 700 nm is within the above range, the lubricant has a sufficiently high hardness, thereby reducing the amount of abrasion when used in an image forming apparatus. Furthermore, as described above, uniform crystals are formed in the lubricant during production, making it less susceptible to cracking, chipping, and fissures. The value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is preferably 3.0 or more and 4.8 or less, and more preferably 3.5 or more and 4.8 or less, which further reduces the amount of scraping when used in an image forming apparatus.

[0021] On the other hand, if the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is less than the above range, the hardness of the lubricant will be insufficient, and the amount of abrasion will increase when used in an image forming device. On the other hand, if the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm exceeds the above range, too many crystal nuclei will be formed during production, which will result in the crystal nuclei segregating and making the lubricant crystals non-uniform, making them more susceptible to cracking, chipping, and fissures during production.

[0022] In this embodiment, it is preferable that the amount of higher fatty acid metal salt (b) is 0.25 to 10 parts by mass per 100 parts by mass of higher fatty acid zinc salt (a). When the amount of higher fatty acid metal salt (b) relative to higher fatty acid zinc salt (a) is within this range, the amount of higher fatty acid metal salt (b) is appropriate, making the lubricant harder and reducing the amount of abrasion when used in an image forming device. Furthermore, the amount of higher fatty acid metal salt (b) is appropriate, making it less likely to crack, chip, or break during production.

[0023] The higher fatty acid in the higher fatty acid zinc salt (a) and the higher fatty acid in the higher fatty acid metal salt (b) preferably have 12 or more carbon atoms. By using a higher fatty acid with 12 or more carbon atoms, the hardness of the lubricant can be sufficiently increased, and the amount of abrasion when used in an image forming device can be reduced. It is preferable that the higher fatty acid has 21 or less carbon atoms. In this way, the hardness of the lubricant can be maintained high, and the amount of abrasion when used in an image forming device can be reduced.

[0024] The higher fatty acid in the higher fatty acid zinc salt (a) preferably contains one or more saturated fatty acids. Examples of such saturated fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and montanic acid. When the higher fatty acid in the higher fatty acid zinc salt (a) is selected from these, the lubricant has a sufficiently high hardness and can reduce abrasion when used in an image forming apparatus. Furthermore, the higher fatty acid is more suitable, so that uniform crystals are formed in the lubricant during production, making it less susceptible to cracking, chipping, and fissures. In this embodiment, the higher fatty acid in the higher fatty acid zinc salt (a) may be an unsaturated fatty acid. Examples of unsaturated fatty acids include palmitoleic acid, oleic acid, elaidic acid, ricinoleic acid, eicosenoic acid, erucic acid, linoleic acid, γ-linolenic acid, α-linolenic acid, punicic acid, and stearic acid.

[0025] The higher fatty acid in the higher fatty acid metal salt (b) preferably contains one or more saturated fatty acids. Examples of such saturated fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and montanic acid. When the higher fatty acid in the higher fatty acid metal salt (b) is selected from these, the lubricant has a sufficiently high hardness and can reduce abrasion when used in an image forming apparatus. Furthermore, the higher fatty acid is more suitable, and uniform crystals are formed in the lubricant during production, making it less susceptible to cracking, chipping, and fissures. Note that in this embodiment, the higher fatty acid in the higher fatty acid metal salt (b) may be an unsaturated fatty acid. Examples of unsaturated fatty acids include palmitoleic acid, oleic acid, elaidic acid, ricinoleic acid, eicosenoic acid, erucic acid, linoleic acid, γ-linolenic acid, α-linolenic acid, punicic acid, and stearic acid.

[0026] The higher fatty acid in the higher fatty acid zinc salt (a) and the higher fatty acid in the higher fatty acid metal salt (b) can be of the same type or different types. The above-mentioned higher fatty acids, whether of the same type or different types, can reduce the amount of abrasion when used in an image forming apparatus, and also reduce the occurrence of cracks, chips, and fissures because uniform crystals are formed in the lubricant during production.

[0027] [Lubricant manufacturing method] The lubricant can be produced by a melt molding method in which the higher fatty acid zinc salt (a) and the higher fatty acid metal salt (b) are thoroughly mixed and melted, poured into a mold having a predetermined shape, and cooled to solidify. The higher fatty acid zinc salt (a) and the higher fatty acid metal salt (b) can be melted by heating at, for example, 120°C to 200°C, preferably 140°C to 180°C, and in one example, 160°C. The melting time is not particularly limited, but can be, for example, 30 minutes to 5 hours. When pouring into a mold, it is preferable to preheat the mold and then cool the molten material after pouring. The mold heating temperature can be, for example, 120°C to 200°C, preferably 140°C to 180°C, and in one example, 160°C. As mentioned above, the lubricant becomes a large number of stable crystal nuclei in which the higher fatty acid metal salt (b) is uniformly dispersed during cooling during production, so it is preferable to appropriately control the cooling rate of the lubricant. A cooling rate that is too fast or too slow is undesirable. The cooling rate of the lubricant can be controlled by adjusting the cooling rate of the mold. The cooling rate of the mold can be, for example, 1°C / min to 10°C / min, preferably 3°C / min to 8°C / min, and as an example, 5°C / min. Then, when the overall temperature reaches 40°C or less, the lubricant is removed from the mold, thereby obtaining the lubricant having a predetermined shape. The mold that can be used has internal dimensions of, for example, a rectangular parallelepiped shape of 8 mm length x 160 mm width x 11 mm height, but is not limited thereto.

[0028] [Image forming equipment] Next, an image forming apparatus according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 is an explanatory cross-sectional view showing an example of the configuration of the image forming apparatus according to this embodiment. Figure 2 is an explanatory cross-sectional view showing an example of the configuration of the main parts of the image forming apparatus according to this embodiment.

[0029] 1, image forming apparatus 100 includes electrophotographic image carriers 111Y, 111M, 111C, and 111Bk. Image forming apparatus 100 also includes coating unit 116Y (FIG. 2) that scrapes lubricant and applies it to the surfaces of image carriers 111Y, 111M, 111C, and 111Bk to form a lubricant coating (not shown). As described above, the lubricant is composed of a higher fatty acid zinc salt (a) and a higher fatty acid metal salt (b) containing a metal salt other than zinc. As described above, the metal species contained in the higher fatty acid metal salt (b) is one or more of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements. As described above, the value obtained by dividing the measured value of the spectral reflectance spectrum of the lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less. Since these components of the lubricant have already been described, a detailed description is omitted here.

[0030] 1 is a so-called tandem color image forming apparatus. This image forming apparatus 100 has four image forming units 110Y, 110M, 110C, and 110Bk, a paper feed conveying unit 150, and a fixing unit 170.

[0031] The image forming units 110Y, 110M, 110C, and 110Bk are arranged vertically. Each of the image forming units 110Y, 110M, 110C, and 110Bk has a rotating drum-shaped image carrier 111Y, 111M, 111C, and 111Bk. Each of the image forming units 110Y, 110M, 110C, and 110Bk has charging units 113Y, 113M, 113C, and 113Bk arranged sequentially along the rotation direction of the image carrier on the outer circumferential surface area. Each of the image forming units 110Y, 110M, 110C, and 110Bk has exposure units 115Y, 115M, 115C, and 115Bk. The image forming units 110Y, 110M, 110C, and 110Bk include developing units 117Y, 117M, 117C, and 117Bk. The image forming units 110Y, 110M, 110C, and 110Bk include primary transfer rollers 133Y, 133M, 133C, and 133Bk. The image forming units 110Y, 110M, 110C, and 110Bk include cleaning units 119Y, 119M, 119C, and 119Bk. Yellow (Y), magenta (M), cyan (C), and black (Bk) toner images are formed on the image carriers 111Y, 111M, 111C, and 111Bk, respectively. Image forming units 110Y, 110M, 110C, and 110Bk are configured similarly except for the colors of the toner images formed on image carriers 111Y, 111M, 111C, and 111Bk, and therefore will be described below using image forming unit 110Y as an example.

[0032] As shown in FIG. 2, in the image forming unit 110Y, the above-mentioned coating means 116Y is provided, for example, downstream of the primary transfer roller 133Y (FIG. 1) in the rotation direction of the image carrier 111Y and upstream of the cleaning means 119Y (FIG. 1).

[0033] (Film forming means) The coating film forming means 116Y scrapes off the lubricant and applies it to the surface of the image carrier 111Y to form a coating of the lubricant. The coating film forming means 116Y is composed of a lubricant application device having the above-mentioned lubricant and an application member such as a brush roller 21 that applies the lubricant to the surface of the image carrier 111Y. Specifically, as shown in FIG. 2, the coating film forming means 116Y is composed of a housing 20, a lubricant stock 22, the brush roller 21, a pressure spring 23, and a drive mechanism (not shown). The lubricant stock 22 is housed in the housing 20 and has a rectangular parallelepiped shape formed from a lubricant. The brush roller 21 has the tip of its brush in contact with the surface of the image carrier 111Y. The brush roller 21 is driven to rotate at a constant speed in the opposite direction to the rotation direction of the image carrier 111Y. The brush roller 21 rubs the surface of the lubricant stock 22 to scrape off powdery lubricant, which is then applied to the surface of the image carrier 111Y to form a lubricant coating. A pressure spring 23 presses the lubricant stock 22 against the brush roller 21. A drive mechanism drives the brush roller 21 to rotate.

[0034] The brush roller 21 may be, for example, a ribbon-shaped pile fabric made by weaving bundles of fibers into a base fabric as pile threads, which is then spirally wound around a metal shaft with the napped side facing outward and bonded. The brush roller 21 in this example is formed by forming a long woven fabric on the peripheral surface of a roller base, with brush bristles made of resin such as polypropylene planted at a high density. From the viewpoint of application ability, straight bristles raised perpendicularly to the metal shaft are preferred. The thread used for the bristles is preferably filament thread, and examples of materials include synthetic resins such as 6-nylon, 12-nylon, polyester, acrylic, and vinylon. The bristles may be kneaded with metals such as carbon and nickel to enhance conductivity. The thickness of the bristles may be, for example, 3 to 7 denier. The length of the bristles may be, for example, 2 to 5 mm. The electrical resistivity of the bristles may be, for example, 1 x 10 10 The Young's modulus of the brush bristles is preferably 4900 to 9800 N / mm 2The density of the brush bristles (number of brush bristles per unit area) is, for example, 50,000 to 200,000 bristles per square inch (50,000 to 200,000 bristles per square inch). 2 ) is preferable. The amount of penetration of the brush roller 21 into the image carrier 111Y is preferably, for example, 0.5 to 1.5 mm. The rotation speed of the brush roller 21 is preferably, for example, 0.3 to 1.5 in terms of a peripheral speed ratio to the image carrier 111Y. The rotation direction of the brush roller 21 may be the same as or opposite to the rotation direction of the image carrier 111Y.

[0035] The pressure spring 23 is used to press the lubricant stock 22 in a direction approaching the image carrier 111Y so that the pressing force of the brush roller 21 against the image carrier 111Y is, for example, 0.5 to 1.0 N.

[0036] In the coating forming means 116Y, the surface of the image carrier 111Y is coated with a film of 1 cm 2 For example, the amount of lubricant applied per unit is 0.5 x 10 -7 ~1.5×10 -7 g / cm 2 This can be controlled by adjusting, for example, the pressing force of the lubricant stock 22 against the brush roller 21 and the rotation speed of the brush roller 21.

[0037] (Image carrier) As the image carrier 111Y, various conventionally known organic image carriers, inorganic image carriers, etc. can be used. As the organic image carrier, for example, one having a layer structure in which an organic photosensitive layer and, if necessary, a protective layer are laminated in this order on a conductive support can be used. Specific examples of the organic image carrier include those having the layer structures (1) and (2) below. (1) A layer structure in which an intermediate layer, a charge generating layer and a charge transport layer as organic photosensitive layers, and a protective layer are laminated in this order on a conductive support. (2) A layer structure in which an intermediate layer, a layer containing a charge generating material and a charge transport material as an organic photosensitive layer, and a protective layer are laminated in this order on a conductive support.

[0038] In this embodiment, the organic image carrier refers to an electrophotographic organic image carrier in which the charge generation function or charge transport function, which is essential for the construction of the organic image carrier, is exerted by an organic compound. The organic image carrier may have an organic photosensitive layer composed of a known organic charge generation material or organic charge transport material. The organic image carrier may have an organic photosensitive layer in which the charge generation function and the charge transport function are exerted by a polymer complex. All such known organic image carriers can be used as the organic image carrier.

[0039] (Charging means) Continuing the explanation, returning to Figure 1, the charging means 113Y uniformly charges the surface of the image carrier 111Y to a negative polarity. As the charging means 113Y, for example, a corona discharge type charger is used.

[0040] (Exposure means) The exposure unit 115Y exposes the surface of the image carrier 111Y, which has been given a uniform potential by the charging unit 113Y, based on an image signal (yellow image signal), to form an electrostatic latent image corresponding to the yellow image. The exposure unit 115Y is composed of an LED in which light-emitting elements are arranged in an array in the axial direction of the image carrier 111Y, and an imaging element, or a laser optical system or the like is used.

[0041] (Developing means) The developing means 117Y supplies toner to the surface of the image carrier 111Y and develops the electrostatic latent image formed on the surface of the image carrier 111Y to form a toner image. Specifically, the developing means 117Y in this example is a developing unit composed of a housing, a developing sleeve, and a voltage application device. The housing contains developer. The developing sleeve is provided within the housing and has a built-in magnet to hold the developer and rotate. The voltage application device applies DC and / or AC bias voltage between the image carrier 111Y and the developing sleeve.

[0042] (Transfer means) The primary transfer roller 133Y, which constitutes the transfer means, transfers the toner image formed on the image carrier 111Y onto the endless belt-like intermediate transfer body 131. The primary transfer roller 133Y is disposed in contact with the intermediate transfer body 131.

[0043] This image forming apparatus 100 employs an intermediate transfer system. In this system, first, toner images formed on image carriers 111Y, 111M, 111C, and 111Bk are transferred to intermediate transfer member 131 by primary transfer rollers 133Y, 133M, 133C, and 133Bk. Thereafter, each toner image transferred onto intermediate transfer member 131 is transferred to transfer material 3 by secondary transfer roller 217. Note that image forming apparatus 100 can also employ a direct transfer system. In this system, toner images formed on the image carriers are transferred directly to the transfer material by transfer means.

[0044] (Cleaning means) The cleaning means 119Y removes toner remaining on the surface of the image carrier 111Y. In this example, the cleaning means 119Y is configured with a cleaning blade. The cleaning blade is disposed so that its tip faces in the opposite direction (counter direction) to the rotation direction of the image carrier 111Y at the contact portion with the surface of the image carrier 111Y.

[0045] The intermediate transfer member 131 is wound around a plurality of rollers 137, 137, 137, 137, and is rotatably supported. Cleaning means 135 is disposed on intermediate transfer body 131 to remove toner remaining on intermediate transfer body 131. Cleaning means 135 is configured with a cleaning blade, similar to cleaning means 119Y. This cleaning blade is disposed with its tip facing in the opposite direction (counter direction) to the rotation direction of intermediate transfer body 131 at the portion where it abuts against the surface of intermediate transfer body 131.

[0046] (Paper feeding and transport means) The paper feed conveying means 150 is provided so as to be able to convey the transfer material 3 in the paper feed cassette 211 to the secondary transfer roller 217 via a plurality of intermediate rollers 213A, 213B, 213C, 213D and a registration roller 215.

[0047] (Fixing means) The fixing means 170 fixes the color image transferred by the secondary transfer roller 217. The paper discharge rollers 219 are provided so as to be able to place the transfer material 3 on a paper discharge tray 221 while nipping the transfer material 3 that has been subjected to the fixing process.

[0048] (toner) The toner used in the image forming apparatus 100 is made up of, but not limited to, toner particles containing a binder resin and a colorant. The toner particles may contain other components such as a release agent, if desired. From the viewpoint of achieving high image quality, the toner particles constituting the toner preferably have a volume average particle size of 2 to 8 μm.

[0049] Examples of methods for producing the toner include, but are not limited to, a conventional pulverization method, a wet melt spheronization method in which the toner is produced in a dispersion medium, and known polymerization methods such as suspension polymerization, dispersion polymerization, and emulsion polymerization aggregation.

[0050] Furthermore, inorganic fine particles such as silica and titania having an average particle size of about 10 to 300 nm, and abrasives having an average particle size of about 0.2 to 3 μm may be added to the toner particles as external additives.

[0051] The toner can be used as a magnetic or non-magnetic one-component developer, but may also be mixed with a carrier and used as a two-component developer. When the toner is used as a two-component developer, the carrier may be magnetic particles made of conventionally known materials such as ferromagnetic metals such as iron, alloys of ferromagnetic metals with aluminum and lead, and compounds of ferromagnetic metals such as ferrite and magnetite.

[0052] (Image formation (transfer) by image forming device) In the image forming apparatus 100 configured as described above, toner images are formed by the image forming units 110Y, 110M, 110C, and 110Bk. Specifically, first, the charging units 113Y, 113M, 113C, and 113Bk discharge the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk to negatively charge them. Next, the exposure units 115Y, 115M, 115C, and 115Bk expose the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk based on an image signal to form electrostatic latent images. Thereafter, the developing units 117Y, 117M, 117C, and 117Bk apply toner to the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk to develop the toner images.

[0053] Next, primary transfer rollers 133Y, 133M, 133C, and 133Bk come into contact with the rotating intermediate transfer body 131. As a result, the toner images of each color formed on image carriers 111Y, 111M, 111C, and 111Bk are sequentially transferred onto the rotating intermediate transfer body 131, and a color image is transferred (primary transfer). During image formation processing, primary transfer roller 133Bk always comes into contact with image carrier 111Bk. Meanwhile, the other primary transfer rollers 133Y, 133M, and 133C come into contact with their corresponding image carriers 111Y, 111M, and 111C only during color image formation.

[0054] Next, the primary transfer rollers 133Y, 133M, 133C, and 133Bk are separated from the intermediate transfer body 131. Thereafter, a coating forming unit scrapes off lubricant and applies it to the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk to form a lubricant coating. Any toner remaining on the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk is then removed by cleaning units 119Y, 119M, 119C, and 119Bk. Thereafter, in preparation for the next image formation process, the surfaces of the image carriers 111Y, 111M, 111C, and 111Bk are neutralized as needed by a neutralization unit (not shown).

[0055] Meanwhile, paper feed conveying means 150 feeds transfer material 3 housed in paper feed cassette 211 and conveys it to secondary transfer roller 217 via multiple intermediate rollers 213A, 213B, 213C, and 213D and registration roller 215. Note that transfer material 3 is a support that carries a final image, such as plain paper or a transparent sheet. Then, secondary transfer roller 217 abuts against rotating intermediate transfer body 131 and transfers the color image onto transfer material 3 all at once (secondary transfer). Secondary transfer roller 217 abuts against intermediate transfer body 131 only when secondary transfer is performed onto transfer material 3. Thereafter, transfer material 3 onto which the color image has been transferred all at once is separated at a portion of intermediate transfer body 131 with a high curvature.

[0056] The transfer material 3 onto which the color image has been transferred in this manner is fixed by fixing means 170, and then sandwiched between discharge rollers 219 and placed on a discharge tray 221 outside the apparatus. After the transfer material 3 onto which the color image has been transferred in a lump is separated from the intermediate transfer body 131, the remaining toner on the intermediate transfer body 131 is removed by cleaning means 135.

[0057] The image forming apparatus 100 described above uses the above-mentioned lubricant, so the amount of abrasion when used in the image forming apparatus 100 can be reduced. In addition, since the image forming apparatus 100 uses the above-mentioned lubricant, it is possible to stably supply a small amount of lubricant while meeting the demands for high speed, compactness, high durability, and high reliability of the image forming apparatus 100. Furthermore, the amount of abrasion of the above-mentioned lubricant can be predicted by using the spectral reflectance spectrum. Therefore, it is possible to select a lubricant that will abrade less than conventional lubricants, and it is possible to maintain high reliability even when used over a long period of time. The above-mentioned lubricant does not break, chip, or crack during manufacturing, so it can provide stable images over a long period of time.

[0058] [Manufacturing method of image forming apparatus] Next, a method for manufacturing an image forming apparatus according to this embodiment (hereinafter, sometimes referred to as "this manufacturing method") will be described with reference to Fig. 3. Fig. 3 is a flowchart illustrating the contents of this manufacturing method. This manufacturing method is for manufacturing the above-described image forming apparatus 100. As shown in Fig. 3, this manufacturing method includes a selection step S1 and an assembly step S2.

[0059] In the selection step S1, the following lubricant is selected. The lubricant is composed of a higher fatty acid zinc (a) and a higher fatty acid metal salt (b) containing a metal salt other than zinc. The metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements. The value obtained by dividing the measured value of the spectral reflectance spectrum of the lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less. Since these components of the lubricant have already been described, a detailed explanation is omitted here. In the selection step S1, it is preferable to select only non-defective lubricants by visual inspection or image evaluation, excluding lubricants that have developed cracks, chips, or fissures during manufacturing. In the incorporation step S2, the lubricant selected in the selection step S1 is incorporated into a coating means (for example, the coating means 116Y). By carrying out these steps, this manufacturing method can manufacture the image forming device 100 provided with the above-described lubricant. [Example]

[0060] Next, specific examples of the present invention will be described, but the present invention is not limited to these.

[0061] (Method of producing lubricant according to Example 1) 100 parts by mass of zinc stearate (higher fatty acid zinc (a)) prepared by reacting stearic acid with zinc hydroxide and 10 parts by mass of calcium stearate (higher fatty acid metal salt (b)) were thoroughly mixed and melted by heating to 160°C. This melt was poured into a mold (internal dimensions: rectangular parallelepiped shape, length 8 mm x width 160 mm x height 11 mm) that had been preheated to 160°C, and then cooled at a rate of 5°C / min. This produced 100 lubricants in the shape of a rectangular parallelepiped, length 8 mm x width 160 mm x height 11 mm.

[0062] (Method of producing lubricant according to Example 2) In the method for preparing the lubricant according to Example 1, the amount of zinc stearate (higher fatty acid zinc salt (a)) was set to 100 parts by mass, and the amount of barium behenate (higher fatty acid metal salt (b)) was set to 0.25 parts by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0063] (Method of producing lubricant according to Example 3) In the method for preparing the lubricant according to Example 1, the amount of zinc stearate, which is the higher fatty acid zinc salt (a), was set to 100 parts by mass, and the amount of lithium stearate, which is the higher fatty acid metal salt (b), was set to 1.0 part by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0064] (Method of producing lubricant according to Example 4) In the method for preparing the lubricant according to Example 1, the amount of zinc behenate (higher fatty acid zinc salt (a)) was set to 100 parts by mass, and the amount of aluminum stearate (higher fatty acid metal salt (b)) was set to 1.0 part by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1. The zinc behenate was prepared in the same manner as in Example 1.

[0065] (Method for producing lubricant according to Example 5) In the method for preparing the lubricant according to Example 1, the amount of zinc stearate, which is the higher fatty acid zinc salt (a), was set to 100 parts by mass, and the amount of calcium stearate, which is the higher fatty acid metal salt (b), was set to 0.24 parts by mass, according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0066] (Method for producing lubricant according to Example 6) In the method for preparing the lubricant according to Example 1, the amount of zinc oleate, which is the higher fatty acid zinc salt (a), was set to 100 parts by mass, and the amount of calcium stearate, which is the higher fatty acid metal salt (b), was set to 1.0 part by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1. The zinc oleate was prepared in the same manner as in Example 1.

[0067] (Method for producing lubricant according to Example 7) In the method for preparing the lubricant according to Example 1, the amount of zinc stearate, which is the higher fatty acid zinc salt (a), was set to 100 parts by mass, and the amount of calcium oleate, which is the higher fatty acid metal salt (b), was set to 1.0 part by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0068] (Method of producing lubricant according to Comparative Example 1) In the method for preparing the lubricant according to Example 1, the amount of zinc stearate (higher fatty acid zinc salt (a)) was set to 100 parts by mass, and no higher fatty acid metal salt (b) was added, according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0069] (Method of producing lubricant according to Comparative Example 2) In the method for preparing the lubricant according to Example 1, the amount of aluminum stearate corresponding to the higher fatty acid metal salt (b) was changed to 100 parts by mass instead of the higher fatty acid zinc salt (a) and the amount of calcium stearate, which is the higher fatty acid metal salt (b), was changed to 1.0 part by mass according to Table 1. Except for these, 100 bottles of each lubricant were prepared in the same manner as in Example 1.

[0070] (Method of producing lubricant according to Comparative Example 3) 100 parts by mass of zinc stearate and 12 parts by mass of calcium stearate were thoroughly mixed and compressed into a mold (a rectangular parallelepiped shape with internal dimensions of 8 mm length x 160 mm width x 11 mm height) to produce 100 lubricants. In other words, Comparative Example 3 was produced by compression molding.

[0071] Evaluation Method (1) Spectral reflectance spectrum The spectral reflectance spectrum of the finished lubricant was measured at wavelengths of 500 nm and 700 nm using an FD-7 manufactured by Konica Minolta, Inc. The measured value of the spectral reflectance spectrum at a wavelength of 500 nm was then divided by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm to determine the value. The measurement conditions for the spectral reflectance spectrum were as follows: (Measurement conditions) Measurement method: Reflection measurement Lighting conditions: M0(A) Density white standard: Absolute value Observation field of view: 2° Observation light source: D65 Polarizing filter: Not installed

[0072] (2) Amount of scraping The lubricant was placed in a full-color printing machine (Accurio PRESS C14000, manufactured by Konica Minolta, Inc.), and 200,000 sheets were continuously printed at 10% coverage in an A4 size at 23°C and 50% RH. The difference in the weight of the lubricant before and after printing was taken as the amount of scraping. Abrasion amounts of 1.0g to 2.0g were rated as excellent, 2.1g to 4.0g as good, and 4.1g or more as poor. The pass / fail judgment of the amount of abrasion was as follows: excellent and good were rated as pass, and poor was rated as fail.

[0073] (3) Moldability Of the 100 lubricants produced, the number of non-defective lubricants excluding those with cracks, chips or fissures was determined as moldability. A sample with 90 to 100 good products out of 100 was rated as excellent, a sample with 71 to 89 good products was rated as good, and a sample with 70 or less was rated as poor. The moldability was judged to be pass if the sample was excellent or good, and fail if it was poor.

[0074] Table 1 shows the blending amounts (parts by mass) of each raw material in Examples 1 to 7 and Comparative Examples 1 to 3, the values ​​obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm, and the evaluation results (amount of scraping and moldability). In Table 1, the values ​​obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm are expressed as "spectral reflectance 500 / 700." In Table 1, "-" indicates that the component is not contained.

[0075] [Table 1]

[0076] As shown in Table 1, Examples 1 to 7 satisfied the requirements of the present invention, and therefore had excellent or good abrasion amounts and moldability. In particular, Examples 1 and 2 had appropriate blending amounts of higher fatty acid zinc (a) and higher fatty acid metal salt (b), and the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm. Therefore, Examples 1 and 2 had excellent abrasion amounts and moldability. These were confirmed to be preferable examples among the Examples. It was confirmed that Examples 1 to 7 were less likely to break, chip, or crack during production, and could reduce abrasion amounts when used in an image forming apparatus.

[0077] In contrast, Comparative Example 1 did not contain the higher fatty acid metal salt (b). Therefore, in Comparative Example 1, the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm did not satisfy the requirements of the present invention. As a result, the scraping amount of Comparative Example 1 was poor.

[0078] Comparative Example 2 did not contain higher fatty acid zinc salt (a), but contained aluminum stearate and calcium stearate corresponding to higher fatty acid metal salt (b). Therefore, the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm for Comparative Example 2 did not satisfy the requirements of the present invention. As a result, the scraping amount for Comparative Example 2 was poor.

[0079] In Comparative Example 3, the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm did not satisfy the requirements of the present invention. As a result, Comparative Example 3 had poor moldability.

[0080] (4) Optical microscope Example 1 and Comparative Example 1 were observed using an optical microscope. The optical microscope used was a DSX1000 manufactured by Olympus Corporation. Images were taken with the optical microscope at a magnification of 140x. Figure 4 is an optical microscope image of Example 1. Figure 5 is an optical microscope image of Comparative Example 1. The scale bars in both Figures 4 and 5 indicate 400 µm.

[0081] Since Example 1 satisfied the requirements of the present invention, it was confirmed that the crystals were uniformly formed, as shown in FIG. On the other hand, Comparative Example 1 did not satisfy the requirements of the present invention. Specifically, Comparative Example 1 did not contain higher fatty acid metal salt (b), and the value obtained by dividing the measured value of the spectral reflectance spectrum at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm was below the predetermined range. Therefore, as shown in Figure 5, it was confirmed that no crystals were formed in Comparative Example 1.

[0082] The solid lubricant, image forming apparatus, and method for manufacturing an image forming apparatus according to the present invention have been described above using embodiments and examples. However, these have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to having all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0083] 100 Image forming device 20 Case 21 Brush roller 22 Lubricant Stock 23 Pressure spring 110Y, 110M, 110C, 110Bk Image forming unit 111Y, 111M, 111C, 111Bk Image carrier 113Y, 113M, 113C, 113Bk Charging means 115Y, 115M, 115C, 115Bk Exposure means 116Y Film forming means 117Y, 117M, 117C, 117Bk developing means 119Y, 119M, 119C, 119Bk Cleaning means 131 Intermediate transfer body 133Y, 133M, 133C, 133Bk Primary transfer roller 135 Cleaning means 137 Laura 150 Paper feed and transport means 170 Fixing means 211 Paper cassette 213A, 213B, 213C, 213D Intermediate rollers 215 Registration roller 217 Secondary transfer roller 219 Paper ejection roller 221 Paper output tray 3 Transfer material

Claims

1. A solid lubricant that is applied to the surface of an image carrier of an electrophotographic image forming apparatus to form a coating on the surface of the image carrier, the solid lubricant comprises (a) a higher fatty acid zinc salt and (b) a higher fatty acid metal salt containing a metal salt other than zinc; the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements; a value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less; A solid lubricant characterized by:

2. Relative to 100 parts by mass of the higher fatty acid zinc salt (a), the higher fatty acid metal salt (b) is 0.25 parts by mass or more and 10 parts by mass or less 2. The solid lubricant according to claim 1, wherein

3. 2. The solid lubricant according to claim 1, wherein the higher fatty acid in the higher fatty acid zinc salt (a) comprises at least one saturated fatty acid.

4. 2. The solid lubricant according to claim 1, wherein the higher fatty acid in the higher fatty acid metal salt (b) comprises at least one saturated fatty acid.

5. an image carrier in an electrophotographic system; a coating forming means for scraping off a solid lubricant and applying it to the surface of the image bearing member to form a coating of the solid lubricant; Equipped with the solid lubricant comprises (a) a higher fatty acid zinc salt and (b) a higher fatty acid metal salt containing a metal salt other than zinc; the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements; a value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum at a wavelength of 700 nm is 2.2 or more and 4.8 or less; An image forming apparatus characterized by:

6. A method for manufacturing the image forming apparatus according to claim 5, a step of selecting a solid lubricant comprising (a) a higher fatty acid zinc salt and (b) a higher fatty acid metal salt containing a salt of a metal other than zinc, wherein the metal species contained in the higher fatty acid metal salt (b) is at least one of metal species belonging to Group 1 elements, metal species belonging to Group 2 elements, and metal species belonging to Group 13 elements, and wherein a value obtained by dividing the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 500 nm by the measured value of the spectral reflectance spectrum of the solid lubricant at a wavelength of 700 nm is 2.2 or more and 4.8 or less; incorporating the selected solid lubricant into the coating means; 10. A method for manufacturing an image forming apparatus, comprising:

Images