Brush, method for manufacturing brush, and image forming apparatus

Abstract

To provide a brush that provides a sufficient pressing force and can be used in an image forming apparatus forming an image using an electrophotographic system to improve the quality of the image.SOLUTION: A brush includes brush bristles, and the brush bristles include a conductive polyester fiber having an endothermic main peak that is an endothermic peak having the maximum endothermic quantity in a DSC curve within a range of 20°C or more and 300°C or less, which is measured by a differential scanning calorimeter during the temperature rise at a rate of temperature rise of 10°C / min, and an endothermic sub peak having a peak top in a region of 155°C or more and 190°C or less in the DSC curve. The brush is used in an image forming apparatus that forms an image using an electrophotographic system.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In brushes used in image forming devices that form images using an electrophotographic method, conductive fibers are used as the material that makes up the brush bristles for the purpose of preventing charging due to contamination from developers including toner and / or for the purpose of applying electricity.

[0003] Patent Document 1 discloses that conductive fibers are used as the material for bristles of a rotating brush used in a lubricant supply device in an image forming apparatus. Furthermore, Patent Document 1 discloses that the conductive fibers are fibers made of resin (such as nylon, acrylic resin, or polyester resin) mixed with a conductivity-imparting agent such as carbon.

[0004] Patent Document 2 discloses that a rotating brush used in a lubricant application device in an image forming apparatus uses conductive threads made of a conductive material as the material for bristles. Patent Document 2 also discloses that examples of the conductive material include nylon resin, acrylic resin, or polyester resin with carbon black dispersed therein. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-310336 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-134555 Summary of the Invention [Problem to be solved by the invention]

[0006] After extensive research, the inventors discovered that the impact of environmental changes on brush bristles varies depending on the type of conductive fiber used to make the bristles. The inventors then discovered that conductive polyester fiber is a preferred material for making brush bristles, because changes in the electrical resistance of the fiber due to moisture absorption tend to be small, and the amount of shrinkage of the outer diameter of the fiber due to moisture absorption tends to be small. However, the inventors discovered that when a brush containing bristles containing conductive polyester fiber is used in an electrophotographic image forming apparatus, sufficient pressing force may not be obtained and / or it may be difficult to improve image quality.

[0007] Therefore, one object of the present invention is to provide a brush that can obtain sufficient pressing force and can realize high-quality images when used in an image forming apparatus that forms images by electrophotography. Another object of the present invention is to provide an image forming apparatus that forms images by electrophotography, equipped with such a brush. [Means for solving the problem]

[0008] The present inventors conducted extensive research to solve the above-mentioned problems. In the course of their research, they discovered that the above-mentioned problems can be solved when the conductive polyester fibers constituting the brush bristles have an endothermic peak that is different from the main peak in a specific temperature range and has a peak top in a range of 155°C or higher. As a result, the present inventors have completed the present invention.

[0009] According to one aspect of the present invention, Includes brush bristles, the brush bristles contain conductive polyester fibers having, in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C at a temperature increase rate of 10°C / min, a main endothermic peak which is an endothermic peak at which the amount of heat absorbed is maximum, and an endothermic subpeak having a peak top in the range of 155°C to 190°C in the DSC curve; A brush can be provided for use in an image forming apparatus that forms an image by an electrophotographic method. [Effects of the Invention]

[0010] According to one aspect of the present invention, it is possible to provide a brush that can obtain sufficient pressing force and that can realize high-quality images when used in an image forming apparatus that forms images by electrophotography. Also, according to another aspect of the present invention, it is possible to provide an image forming apparatus that forms images by electrophotography and that includes the brush. [Brief explanation of the drawings]

[0011] Advantages and features provided by one or more embodiments of the present invention will be more fully understood from the following detailed description and the accompanying drawings, which are for purposes of illustration only and are not intended to define the limits of the invention. [Figure 1] 1 is a schematic cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment. [Figure 2] 1 is a schematic cross-sectional view illustrating an example of a configuration of a main part of an image forming unit 31Y in an image forming apparatus according to an embodiment. [Figure 3] 10 is a schematic diagram illustrating a method for measuring a pressing force that a member that is in sliding contact with the brush receives from the brush when the brush rotates. FIG. [Figure 4] 1 is a graph showing an example of a DSC curve measured by a differential scanning calorimeter, for explaining a method for evaluating an endothermic peak. [Figure 5] 1 is a graph showing an example of a DSC curve measured by a differential scanning calorimeter, for explaining a method for evaluating an endothermic peak. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings as necessary. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, the dimensional proportions in the drawings are exaggerated for the sake of convenience and may differ from the actual proportions.

[0013] While the present invention will be described below with reference to exemplary embodiments, it should be understood that the present invention is not limited to the following exemplary embodiments and can be modified in various ways within the scope of the claims. The exemplary embodiments described in this specification can be combined in any manner to form other exemplary embodiments.

[0014] In this specification, the range "X to Y" means "X or more and Y or less." Unless otherwise specified, operations and measurements of physical properties are performed at room temperature (20 to 25°C) and a relative humidity of 40 to 50% RH.

[0015] <Brush and its manufacturing method> One aspect of the present invention is Includes brush bristles, the brush bristles contain conductive polyester fibers having, in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C at a temperature increase rate of 10°C / min, a main endothermic peak which is an endothermic peak at which the amount of heat absorbed is maximum, and an endothermic subpeak having a peak top in the range of 155°C to 190°C in the DSC curve; The present invention relates to a brush used in an image forming apparatus that forms an image by an electrophotographic method.

[0016] In this specification, the term "main endothermic peak" refers to the endothermic peak at which the amount of endotherm is greatest in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C during heating at a rate of 10°C / min. In this specification, the term "sub-endothermic peak" refers to an endothermic peak different from the main endothermic peak in a DSC curve measured with a differential scanning calorimeter during heating at a rate of 10°C / min.

[0017] In this specification, a conductive polyester fiber having, in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C during heating at a heating rate of 10°C / min, a main endothermic peak which is an endothermic peak with the maximum amount of endothermic heat, and an endothermic subpeak having a peak top in the range of 155°C to 190°C in the DSC curve, is also referred to as a conductive polyester fiber (I).

[0018] The conductive polyester fiber (I) has at least one endothermic subpeak.

[0019] In this specification, the main endothermic peak, which is the endothermic peak at which the amount of heat absorbed is the maximum in a DSC curve measured using a differential scanning calorimeter in the range of 20°C to 300°C when the temperature is increased at a rate of 10°C / min, is also simply referred to as the "main peak".

[0020] In this specification, an endothermic subpeak having a peak top in the region of 155°C or higher and 190°C or lower in a DSC curve measured with a differential scanning calorimeter in the range of 20°C or higher and 300°C or lower at a heating rate of 10°C / min is also simply referred to as a "subpeak having a peak top in the region of 155°C or higher and 190°C or lower."

[0021] Therefore, it can be said that the conductive polyester fiber (I) has a main peak and a sub-peak having a peak top in the region of 155°C or higher and 190°C or lower.

[0022] In this specification, an image forming apparatus that forms an image by electrophotography is also simply referred to as an "image forming apparatus."

[0023] The inventors attempted to increase the brush's pressing force by increasing the stiffness of the brush bristles. However, they found that increasing the diameter of each fiber with this method reduces the fiber density, which tends to result in uneven scraping and a decrease in image quality in the image forming apparatus. The inventors also attempted to increase the brush's pressing force by increasing the brush's pressing force. However, they found that this method leads to brush wear over the long term, which tends to result in insufficient pressing force and / or a decrease in image quality in the image forming apparatus. The inventors then attempted to increase the brush's pressing force by shortening the brush bristle height without changing the pressing force. However, they found that this method results in a large fluctuation in pressing force relative to the pressing force, which tends to result in a decrease in image quality in the image forming apparatus. After extensive research, the inventors surprisingly found that the brush according to the present embodiment can solve the above problems.

[0024] The inventors speculate that the mechanism by which the brush according to this embodiment solves the above-mentioned problems is as follows. Compared to nylon and acrylic, polyester has a higher glass transition temperature and tends to exhibit more variable crystallization. Large variations in the crystallization state of the individual fibers constituting the brush bristles affect the bristles' elastic modulus, reducing the brush's pressing force and making the bristles more susceptible to settling. Meanwhile, in the brush according to the above embodiment, the conductive polyester fibers contained in the bristles have a main peak and a subpeak with a peak top in the range of 155°C to 190°C. Polymers with a certain degree of molecular orientation have folded molecular chains within the structure and amorphous portions surrounding them formed by the folding of the molecular chains. While the details are unclear, the presence of crystalline and amorphous portions in polyester is related to the peak top position of the endothermic subpeak, which is an endothermic peak distinct from the endothermic main peak in polyester. When the conductive polyester fiber has a sub-peak with a peak top in the range of 155°C to 190°C, the individual conductive polyester fibers constituting the brush bristles undergo more advanced molecular orientation, resulting in a greater amount of oriented crystals. The individual conductive polyester fibers constituting the brush bristles exhibit reduced variation in their crystallization state. As a result, sufficient pressing force is obtained by the brush, improving the stability of the brush's rubbing force. Therefore, by using the brush according to this embodiment in an image forming apparatus, high-quality images can be achieved. Note that the above mechanism is based on speculation, and the technical scope of the present invention is not limited by this mechanism.

[0025] The brush according to this embodiment will be described in detail below.

[0026] (Brush structure) The brush according to this embodiment includes brush bristles. The brush bristles are composed of a plurality of fibers. The brush bristles of the brush according to this embodiment include conductive polyester fibers (conductive polyester fibers (I)) having a main peak and a sub-peak with a peak top in the range of 155°C or higher and 190°C or lower. In addition to the conductive polyester fibers (I), the brush bristles may further include at least one type of fiber selected from the group consisting of other polyester fibers and fibers other than polyester fibers. In one embodiment, the brush bristles are preferably composed only of conductive polyester fibers (I).

[0027] In one embodiment, the brush preferably further includes a base in addition to the bristles. The base is not particularly limited as long as it functions as a foundation for the brush, but is preferably, for example, a cylindrical or columnar member. Specific examples of the base include, but are not particularly limited to, a metal core. A known core may be used as the core. The metal core is not particularly limited to, but is, for example, a metal shaft such as a steel shaft, a stainless steel shaft, or an aluminum shaft. Among these, a stainless steel shaft is preferred. The outer diameter of the metal core is not particularly limited to, but is preferably, for example, 4.0 mm or more and 10.0 mm or less. The length of the metal core is not particularly limited to, but is preferably, for example, 300 mm or more and 500 mm or less, or 350 mm or more and 450 mm or less. In one embodiment, the brush may further include a base cloth in addition to the bristles, or may further include a base cloth and a base in addition to the bristles. In the brush, the base cloth may also serve as the base. A known base cloth may be used as the base cloth. The base fabric is not particularly limited, but examples thereof include nylon base fabric, acrylic base fabric, and polyester base fabric. The thickness of the base fabric is not particularly limited, but is preferably 0.1 mm to 10 mm, more preferably 0.1 mm to 5 mm, and even more preferably 0.1 mm to 1 mm. In one embodiment, the brush preferably has a base fabric in which a plurality of fibers including conductive polyester fibers (I) are woven and implanted, and a metal core. In this case, it is more preferable that the plurality of fibers are made only of a plurality of conductive polyester fibers (I). In one embodiment, the brush preferably has a base fabric in which a plurality of fiber bundles, each of which is a bundle of fibers including conductive polyester fibers (I), are woven and implanted, and a metal shaft. In this case, it is more preferable that the fiber bundle is made only of a bundle of fibers (I).

[0028] The bristle height of the brush bristles is not particularly limited, but is preferably 1.0 mm to 5.0 mm, more preferably 2.0 mm to 4.0 mm, and even more preferably 2.5 mm to 3.5 mm. The bristle height can be determined as follows: When the brush includes a base but not a backing fabric, the bristle height refers to the distance from the surface of the base to the outermost surface where fibers exist (the outermost surface of the brush) in a direction perpendicular to the surface (in the case where the base is cylindrical or cylindrical, the radial direction from the central axis of the base). When the brush includes a base and a backing fabric, the bristle height refers to the distance from the surface of the backing fabric to the outermost surface where fibers exist (the outermost surface of the brush) in a direction perpendicular to the surface (in the case where the base is cylindrical or cylindrical, the radial direction from the central axis of the base).

[0029] When the brush bristles include fiber bundles formed by bundling multiple fibers, the bundle fineness of the brush bristles is not particularly limited. In this specification, bundle fineness refers to the thickness of the fiber bundle formed by bundling multiple fibers. The bundle fineness of the brush bristles is preferably 1 decitex to 1,000 decitex, more preferably 10 decitex to 500 decitex, and even more preferably 100 decitex to 300 decitex. The bundle fineness of the brush bristles is further preferably 150 decitex to 250 decitex, and particularly preferably 200 decitex to 250 decitex. Tex is a unit of measurement for the thickness of a fiber or thread, expressed as the mass [g] of a fiber or thread 1,000 m long. One tex indicates that a fiber or thread has a mass of 1 g per 1,000 m long. 1 decitex represents 1 / 10 of 1 tex, so 10 decitex = 1 tex.

[0030] When the brush bristles include fiber bundles each made up of a plurality of fibers, the bundle density of the brush bristles is not particularly limited. In this specification, the bundle density refers to the density of the fiber bundles each made up of a plurality of fibers (the number of fiber bundles per unit area). The bundle density of the brush bristles is preferably 10 kF / inch. 2 More than 500kF / inch2 More preferably, it is 50 kF / inch or less. 2 More than 400kF / inch 2 More preferably, it is 100 kF / inch or less. 2 More than 300kF / inch 2 The bundle density of the brush bristles is more preferably 120 kF / inch or less. 2 More than 250kF / inch 2 It is particularly preferable that the value is 180 kF / inch or less. 2 More than 220kF / inch 2 The bundle density of the brush bristles is preferably 1 kb / cm 2 More than 78k books / cm 2 More preferably, 7k strands / cm or less. 2 More than 63k pieces / cm 2 More preferably, it is 15k strands / cm or less. 2 More than 47k pieces / cm 2 The bundle density of the brush bristles is more preferably 18k bristles / cm 2 More than 39k pieces / cm 2 and particularly preferably 27 k pieces / cm 2 More than 35k pieces / cm 2 Here, "k fibers / cm 2 " is "x10 3 book / cm 2 As will be described later, when the fiber bundle is provided in a loop shape, one loop is regarded as two fiber bundles.

[0031] The shape of the brush bristles is not particularly limited. In one embodiment, the brush may be a straight bristle brush or a loop brush, but is preferably a straight bristle brush. In a straight bristle brush, the fibers (or bundles of such fibers) constituting the brush bristles are provided in a straight bristle shape on the brush. In a straight bristle brush, only one end of the fibers is fixed. In a straight bristle brush, it is preferable that the tips of the fibers are present on the brush surface. In a loop brush, the fibers (or bundles of such fibers) constituting the brush bristles are provided in a loop shape on the brush. In a loop brush, the fibers are fixed to form a loop shape. In a loop brush, generally, multiple fibers are bundled together (in the form of a fiber bundle), and the fiber bundle is fixed to form a loop shape. In one embodiment, the conductive polyester fiber (I) may be provided in a straight bristle shape on the brush. In one embodiment, the fiber (multiple fibers) containing the conductive polyester fiber (I) may be provided in a straight bristle shape on the brush. A fiber bundle formed by bundling multiple fibers containing the conductive polyester fiber (I) may be provided in a straight bristle shape on the brush. A fiber bundle formed by bundling a plurality of conductive polyester fibers (I) may be provided in the brush in a straight bristle shape. A fiber bundle containing the conductive polyester fiber (I) and a fiber bundle not containing the conductive polyester fiber (I) may be provided in the brush in a straight bristle shape. In one embodiment, the conductive polyester fiber (I) may be provided in the brush in a loop shape. In one embodiment, a fiber (plurality of fibers) containing the conductive polyester fiber (I) may be provided in the brush in a loop shape. A fiber bundle formed by bundling a plurality of fibers containing the conductive polyester fiber (I) may be provided in the brush in a loop shape. A fiber bundle formed by bundling a plurality of conductive polyester fibers (I) may be provided in the brush in a loop shape. In a brush according to one embodiment, a fiber bundle formed by bundling a plurality of fibers containing the conductive polyester fiber (I) may be woven into a base fabric in a linear or loop shape and implanted. In a brush according to one embodiment, a fiber bundle formed by bundling a plurality of conductive polyester fibers (I) may be woven into a base fabric in a linear or loop shape and implanted.The fiber bundle may be a fiber bundle in which a plurality of fibers are bundled together without being twisted, or a fiber bundle in which a plurality of fibers are bundled together and twisted to form an integrated bundle.

[0032] The direction of the brush bristles is not particularly limited. The brush bristles may be upright or tilted. In this specification, the term "upright" refers to a state in which the fibers constituting the brush bristles are arranged so that the tips of the fibers (or fiber bundles) or the tips of the loops point in a direction that is approximately perpendicular to the surface of the base or the backing fabric (in the case of a cylindrical or columnar base, approximately a radial direction from the central axis of the base). The term "approximately perpendicular" refers to a direction that is completely perpendicular or approximately perpendicular. The term "approximately radial" refers to a direction that is completely radial or approximately radial. In the upright state, the fibers or fiber bundles are not limited to being linear. The term "tilted" refers to a state in which the fibers constituting the brush bristles are arranged so that the tips of the fibers (or fiber bundles) or the tips of the loops point in a direction that is perpendicular to the surface of the base or the backing fabric (in the case of a cylindrical or columnar base, approximately a radial direction from the central axis of the base). The slanted bristles are not particularly limited, and examples thereof include the slanted bristles of known brushes. In a slanted bristles state, the fibers or fiber bundles may be straight or not, and the fibers, fiber bundles, or loops may be curved, for example. The slanted bristles state is preferably achieved by a slanting treatment, which will be described later. In one embodiment, the brush is preferably a brush that has been subjected to a slanting treatment. In one embodiment, the brush bristles are preferably arranged in a slanted state.

[0033] In one embodiment, the brush may be a rotary brush (brush roller) or a rod-shaped brush (bar brush), but is preferably a rotary brush. In a rotary brush, the bristles of the brush slide against the object while the brush is rotating. The outer diameter of the rotary brush is not particularly limited, but is preferably 5 mm to 100 mm, more preferably 10 mm to 50 mm, and even more preferably 12 mm to 25 mm.

[0034] (fiber) In the brush according to this embodiment, the brush bristles contain conductive polyester fibers (I). In this specification, conductive polyester fibers are fibers having a surface resistance of 10 at a temperature of 23°C and a relative humidity of 50% RH. 12 The surface resistance of the conductive polyester fiber (I) at a temperature of 23°C and a relative humidity of 50% RH is not particularly limited as long as it is within the above range. The surface resistance of the conductive polyester fiber (I) at a temperature of 23°C and a relative humidity of 50% RH is preferably 10 3 Ω / cm or more 10 12 Ω / cm or less, and more preferably 10 4 Ω / cm or more 10 11 The surface resistance of the conductive polyester fiber (I) at a temperature of 23°C and a relative humidity of 50% RH is more preferably 10 5 Ω / cm or more 10 10 The surface resistance of the conductive polyester fiber (I) and the conductive polyester fiber material described below can be measured at 23°C, 50% RH, and an applied voltage of 100 V using a commercially available insulation resistance meter. Details of the measurement method will be described in the Examples.

[0035] The polyester contained in the conductive polyester fiber (I) is not particularly limited, and known polyesters may be used. Specific examples of polyesters include, but are not limited to, polyalkylene terephthalates such as polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT); copolymer polyesters obtained by copolymerizing at least one compound selected from the group consisting of ethylene glycol, propylene glycol (also known as 1,2-propanediol), trimethylene glycol (also known as 1,3-propanediol), 1,4-butanediol, polyethylene glycol, polypropylene glycol, and polybutylene glycol with terephthalic acid and / or a terephthalic acid derivative and a third component; and biodegradable polyesters such as polylactic acid (PLA), polybutylene succinate, and aliphatic polyesters (e.g., polyε-caprolactone). The polyesters may be used alone or in combination. The conductive polyester fiber (I) preferably contains only one type of polyester. The content of the polyester in the conductive polyester fiber (I) is not particularly limited. The content of the polyester in the conductive polyester fiber (I) is preferably 50% by mass or more and less than 100% by mass, more preferably 60% by mass or more and less than 100% by mass, and even more preferably 70% by mass or more and 95% by mass or less, based on the total mass of the conductive polyester fiber (I).

[0036] The derivative of terephthalic acid used as a raw material for the copolymer polyester is not particularly limited, but examples thereof include terephthalic anhydride, dialkyl terephthalate (e.g., dimethyl terephthalate, etc.), etc. The third component used as a raw material for the copolymer polyester is not particularly limited, but examples thereof include dicarboxylic acids such as adipic acid and isophthalic acid (excluding terephthalic acid), diols (excluding ethylene glycol, propylene glycol, trimethylene glycol, and 1,4-butanediol) and / or polyalkylene glycols (excluding polyethylene glycol, polypropylene glycol, and polybutylene glycol), oxycarboxylic acids, etc.

[0037] The weight-average molecular weight (Mw) of the polyester is not particularly limited, but may be, for example, within the range of 1,500 to 2,000,000. The weight-average molecular weight (Mw) of the polyester can be calculated as a polystyrene-equivalent value by, for example, gel permeation chromatography (GPC) using a calibration curve prepared using monodisperse polystyrene standard particles as the polystyrene for calibration curve measurement.

[0038] The conductive polyester fiber (I) may further contain a conductive material in addition to polyester. By adding a conductive material to the polyester fiber, the conductivity (e.g., surface resistance value) of the polyester fiber can be adjusted. The conductive material is not particularly limited, but examples thereof include carbon black, metal particles, and metal oxide particles. The conductive material may be a single material, or two or more materials may be used in combination. The content of the conductive material in the conductive polyester fiber (I) is not particularly limited, but is preferably 5% by mass or more and 30% by mass or less, based on the total mass of the conductive polyester fiber (I). When the conductive polyester fiber (I) contains two or more conductive materials, the content of the conductive materials refers to the total amount of these materials.

[0039] The conductive polyester fiber (I) may or may not further contain components (other components) other than the polyester and the conductive material. Examples of the components other than the polyester and the conductive material include conventionally known additives for polyester fibers.

[0040] The brush bristles may contain other fibers in addition to the conductive polyester fibers (I). The other fibers may be conductive polyester fibers or fibers other than conductive polyester fibers. The brush bristles may contain a single type of conductive polyester fiber, or may contain two or more types of conductive polyester fibers. When the brush bristles contain two or more types of conductive polyester fibers, at least one conductive polyester fiber selected from the group consisting of two or more types of conductive polyester fibers is conductive polyester fiber (I). The brush bristles preferably contain a single type of conductive polyester fiber (I). The brush bristles may or may not further contain fibers other than conductive polyester fibers. It is preferable that the brush bristles do not contain fibers other than conductive polyester fibers, and it is particularly preferable that the brush bristles are made only of conductive polyester fibers (I).

[0041] The conductive polyester fiber material (hereinafter also referred to simply as "conductive polyester fiber material") for producing the conductive polyester fiber (I) may be a manufactured product or a commercially available product. Examples of commercially available conductive polyester fiber materials include, but are not limited to, Beltron (registered trademark) polyester fibers (e.g., BR-1) manufactured by KR Seiren Co., Ltd., Clacarbo polyester fibers manufactured by Kuraray Trading Co., Ltd., SCIMA manufactured by Toray Industries, Inc., and Megana manufactured by Unitika Trading Co., Ltd. The conductive polyester fiber (I) may be produced by a manufacturing method that includes heat-treating the conductive polyester fiber material in the final step of one or more steps that include heat-treating the conductive polyester fiber material, as described below.

[0042] The peak top temperature of the main peak in the conductive polyester fiber (I) is not particularly limited. The temperature range in which the peak top temperature of the main peak in the conductive polyester fiber (I) exists is preferably higher than 190°C, more preferably higher than 190°C to 290°C, and even more preferably 200°C to 270°C. The temperature range in which the peak top temperature of the main peak in the conductive polyester fiber (I) exists is particularly preferably 220°C to 250°C.

[0043] The endothermic value of the main peak in the conductive polyester fiber (I) is not particularly limited. The endothermic value of the main peak in the conductive polyester fiber (I) is preferably 30.0 mJ / mg or more and 60.0 mJ / mg or less, more preferably 35.0 mJ / mg or more and 55.0 mJ / mg or less. The endothermic value of the main peak in the conductive polyester fiber (I) is further preferably 38.0 mJ / mg or more and 50.0 mJ / mg or less, and particularly preferably 40.0 mJ / mg or more and 45.0 mJ / mg or less.

[0044] In the conductive polyester fiber (I), the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C is not particularly limited as long as it is within this range. In the conductive polyester fiber (I), the temperature range in which the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C exists is preferably 160°C to 190°C, more preferably 165°C to 190°C. In the conductive polyester fiber (I), the temperature range in which the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C exists is further preferably 170°C to 190°C, even more preferably 175°C to 190°C. In the conductive polyester fiber (I), the temperature range in which the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C exists is further preferably 175°C to 185°C, especially preferably 180°C to 185°C. Within these ranges, the pressing force of the brush is improved, and higher quality images tend to be obtained in the image forming apparatus.

[0045] In the conductive polyester fiber (I), the value obtained by subtracting the temperature at the peak start position from the temperature at the peak end position of a subpeak having a peak top in the range of 155°C to 190°C inclusive is not particularly limited. In this specification, the value obtained by subtracting the temperature at the peak start position from the temperature at the peak end position of an endothermic peak is also simply referred to as the "peak width." In the conductive polyester fiber (I), the peak width of a subpeak having a peak top in the range of 155°C to 190°C inclusive is preferably 70°C or less, more preferably 60°C or less, and even more preferably 40°C or less (lower limit: greater than 0°C). In the conductive polyester fiber (I), the peak width of a subpeak having a peak top in the range of 155°C to 190°C inclusive is more preferably 35°C or less, even more preferably 31°C or less, and particularly preferably less than 30°C (lower limit: greater than 0°C). Within these ranges, the pressing force of the brush is further improved, and higher quality images tend to be obtained in an image forming apparatus. Even when the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C is in a temperature range narrower than 155°C to 190°C, it is clear that the peak width of the subpeak is preferably within the ranges listed above. Such a temperature range is not particularly limited. Examples of such a temperature range include 160°C to 190°C, 165°C to 190°C, 165°C to 185°C, 170°C to 185°C, 175°C to 185°C, and 180°C to 185°C.

[0046] The endothermic amount of a sub-peak having a peak top in the range of 155°C to 190°C in the conductive polyester fiber (I) is not particularly limited as long as it is smaller than the endothermic amount of the main peak. In the conductive polyester fiber (I), the endothermic amount of a sub-peak having a peak top in the range of 155°C to 190°C in the conductive polyester fiber (I) is preferably 1.0 mJ / mg or more but less than 30.0 mJ / mg, more preferably 2.5 mJ / mg or more but less than 10.0 mJ / mg. In the conductive polyester fiber (I), the endothermic amount of a sub-peak having a peak top in the range of 155°C to 190°C in the conductive polyester fiber (I) is further preferably 2.5 mJ / mg or more but 5.0 mJ / mg or less, and even more preferably more than 2.6 mJ / mg but 4.0 mJ / mg or less. In the conductive polyester fiber (I), the endothermic amount of a sub-peak having a peak top in the range of 155°C to 190°C in the conductive polyester fiber (I) is particularly preferably more than 3.0 mJ / mg but 3.5 mJ / mg or less. Within these ranges, the brush pressing force is further improved, and higher-quality images tend to be obtained. Even when the peak top temperature of a subpeak having a peak top in the range of 155°C to 190°C is in a temperature range narrower than 155°C to 190°C, it is clear that the endothermic heat of the subpeak is preferably within the ranges listed above. Such temperature ranges are not particularly limited. Examples of such temperature ranges include 160°C to 190°C, 165°C to 190°C, 165°C to 185°C, 170°C to 185°C, 175°C to 185°C, and 180°C to 185°C.

[0047] The peak top temperature of each endothermic peak of the conductive polyester fiber (I) can be determined from a DSC curve measured in the range of 20°C to 300°C using a differential scanning calorimeter at a heating rate of 10°C / min. The peak start temperature, peak end temperature, peak width, and endothermic amount of each endothermic peak of the conductive polyester fiber (I) can be determined from a DSC curve measured in the range of 20°C to 300°C using a differential scanning calorimeter at a heating rate of 10°C / min. Details of the measurement method are described in the Examples. When the brush bristles contain multiple types of fibers, in this evaluation, a measurement sample is prepared for each type of fiber and measurements are performed, and the characteristics of each endothermic peak are determined for each type of fiber. For example, when the brush bristles contain multiple types of conductive polyester fibers, in this evaluation, a measurement sample is prepared for each type of conductive polyester fiber and measurements are performed, and the characteristics of each endothermic peak are determined for each type of conductive polyester fiber. For example, when the brush bristles contain multiple types of conductive polyester fibers (I), in this evaluation, a measurement sample is prepared for each type of conductive polyester fiber (I), and measurements are performed, and the characteristics of each endothermic peak are determined for each type of conductive polyester fiber (I).

[0048] 4 and 5 are graphs showing examples of DSC curves measured by a differential scanning calorimeter to illustrate a method for evaluating endothermic peaks. Two endothermic peaks are observed in the DSC curve of FIG. 4, and one endothermic peak is observed in the DSC curve of FIG. 5. Two minimum values ​​are observed in the endothermic peaks at the higher temperatures in FIG. 4 and in the DSC curve of FIG. 5. However, if these endothermic peaks are interpreted as overlapping endothermic peaks with the two minimum values ​​being the peak-top temperatures, it is difficult to accurately evaluate the endothermic amounts of each peak. Therefore, in this specification, even if two or more minimum values ​​exist in one endothermic peak in a DSC curve, this single endothermic peak is treated as a single endothermic peak. Furthermore, when two or more minimum values ​​exist in one endothermic peak, the values ​​on the DSC curve are calculated by subtracting the values ​​on the extension of the baseline at the temperatures showing the two or more minimum values ​​in the endothermic peak. The temperature that indicates the minimum value in the endothermic peak portion, which is the largest of the two or more calculated values, is treated as the peak-top temperature of the endothermic peak. Therefore, it is determined that the DSC curve in Figure 4 has two endothermic peaks: one corresponding to the endothermic peak portion on the low-temperature side and the other corresponding to the endothermic peak portion on the high-temperature side. Also, it is determined that the DSC curve in Figure 5 has one endothermic peak corresponding to one endothermic peak portion.

[0049] When only one endothermic peak is observed in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C when the temperature is increased at a rate of 10°C / min, the endothermic peak is treated as the main endothermic peak.

[0050] The single-yarn fineness of the conductive polyester fiber (I) is not particularly limited. The single-yarn fineness of the conductive polyester fiber (I) is preferably 1.0 decitex or more and 10.0 decitex or less, more preferably 2.0 decitex or more and 8.0 decitex or less, and even more preferably 3.0 decitex or more and 6.0 decitex or less. The single-yarn fineness of the fiber (I) is more preferably 3.0 decitex or more and 5.0 decitex or less, even more preferably 3.0 decitex or more and 4.5 decitex or less, and particularly preferably 3.2 decitex or more and 4.0 decitex or less. Note that tex is a unit of measurement for the thickness of a fiber or thread, and is a unit that expresses the thickness of a fiber or thread in terms of the mass [g] of a fiber or thread per 1,000 m in length. 1 tex indicates that the fiber or thread has a mass of 1 g per 1,000 m in length. 1 decitex represents 1 / 10 of 1 tex, so 10 decitex = 1 tex.

[0051] (Brush manufacturing method) The method for producing the brush according to this embodiment is not particularly limited. For example, the brush according to one embodiment can be produced by a production method including production conditions in which the brush bristles contain the conductive polyester fibers (I). Therefore, it can be said that another aspect of the present invention relates to a method for producing the brush according to the above embodiment.

[0052] The brush manufacturing method preferably includes one or more steps including heat-treating a conductive polyester fiber material. The final step of the one or more steps preferably includes heat-treating the conductive polyester fiber material at a temperature between 155°C and 190°C. In this specification, the final step of the one or more steps including heat-treating the conductive polyester fiber material is also simply referred to as the "final step including heat treatment." As mentioned above, in this specification, the conductive polyester fiber material for manufacturing the conductive polyester fiber (I) is also simply referred to as the "conductive polyester fiber material." Through the heat-treatment of the conductive polyester fiber material in the final step including heat treatment, the conductive polyester fiber material can become the conductive polyester fiber (I). This method makes it easier to realize the conductive polyester fiber (I) in the manufactured brush. The mechanism behind this is presumed to be as follows: In general polyesters, the amount of crystallinity varies depending on the heat treatment conditions. In polymers with a certain degree of molecular orientation, folded molecular chains exist within the structure, and amorphous portions formed around them due to the influence of the folded molecular chains exist. The amorphous portion of the polyester can be heat-treated at a sufficiently high temperature to improve the mobility of molecular chains. This heat treatment and subsequent cooling process can improve the molecular orientation of the polyester and / or promote crystallization. Therefore, by controlling the heat treatment temperature in the final step of the brush manufacturing process, including the heat treatment, it is possible to obtain conductive polyester fibers that further promote molecular orientation, increase the amount of oriented crystals, and reduce the variation in the crystallization state. The above mechanism is based on speculation, and the technical scope of the present invention is not limited by this mechanism. The final step including the heat treatment is not particularly limited, but is preferably the final step including the heat treatment in a manufacturing method (brush manufacturing method) using a woven fabric containing a conductive polyester fiber material.

[0053] The conditions for the heat treatment in the final step including heat treatment are not particularly limited as long as the heat treatment temperature is 155°C or higher and 190°C or lower. The heat treatment temperature in the final step including heat treatment is preferably 160°C or higher and 190°C or lower, more preferably 165°C or higher and 190°C or lower, even more preferably 170°C or higher and 190°C or lower, and even more preferably 175°C or higher and 190°C or lower. The heat treatment temperature in the final step including heat treatment is particularly preferably 175°C or higher and 185°C or lower. Within these ranges, the pressing force of the manufactured brush is further improved, and higher quality images tend to be obtained in the image forming apparatus. The heat treatment time in the final step including heat treatment is not particularly limited, but is preferably 1 minute or higher and 15 minutes or lower, more preferably 2 minutes or higher and 10 minutes or lower, even more preferably 3 minutes or higher and 7 minutes or lower, and particularly preferably 2 minutes or higher and 6 minutes or lower. Within these ranges, the pressing force of the manufactured brush is further improved, and higher quality images tend to be obtained.

[0054] The heat treatment may be any treatment including heating, and the method is not particularly limited. The heat treatment method is not particularly limited, and for example, a known method can be used. Examples of equipment used for the heat treatment include a drying oven. The heat treatment can be carried out, for example, by aging the brush in a drying oven before the heat treatment in the final step including the heat treatment.

[0055] The brush according to one embodiment may be manufactured by a known manufacturing method, except that the manufacturing conditions include those that result in the brush bristles containing conductive polyester fibers (I). In one embodiment, the method for manufacturing the brush includes, for example, a method including manufacturing a brush before a final step including a heat treatment using a woven fabric containing a conductive polyester fiber material, and carrying out the final step including a heat treatment. In one embodiment, the method for manufacturing the brush includes, for example, a method including the following steps (a) to (c): (a) manufacturing a conductive polyester fiber material and / or manufacturing a woven fabric containing a conductive polyester fiber material; (b) manufacturing a brush before a final step including a heat treatment using the manufactured woven fabric; and (c) carrying out the final step including a heat treatment.

[0056] The raw material of the conductive polyester fiber material is not particularly limited. It is preferable that the raw material of the conductive polyester fiber material contains the polyester described above for the conductive polyester fiber (I). The polyester used as the raw material is preferably a polyester that has an endothermic subpeak with a peak top in the region below 155°C in a DSC curve measured with a differential scanning calorimeter in the range of 20°C to 300°C at a heating rate of 10°C / min. However, the polyester used as the raw material is not limited thereto. The raw material of the conductive polyester fiber material may further contain the conductive material described above for the conductive polyester fiber (I) and / or other components, as necessary. The manufacturing method of the conductive polyester fiber material, the manufacturing method of a woven fabric containing the conductive polyester fiber material, and the manufacturing method of a brush using the manufactured woven fabric are not particularly limited, and known methods may be used. The surface resistance value range of the conductive polyester fiber material is not particularly limited. Preferred examples of the surface resistance value range of the conductive polyester fiber material include the same range as the surface resistance value range of the conductive polyester fiber (I) described above. The range of the monofilament fineness of the conductive polyester fiber material is not particularly limited. Preferred examples of the range of the single filament fineness of the conductive polyester fiber material include the same range as the range of the single filament fineness of the conductive polyester fiber (I) described above. Commercially available conductive polyester fiber materials may also be used. As mentioned above, commercially available conductive polyester fiber materials are not particularly limited, but examples include Beltron (registered trademark) polyester fibers (e.g., BR-1, etc.) manufactured by KR Seiren Co., Ltd., Clacarbo polyester fibers manufactured by Kuraray Trading Co., Ltd., SCIMA manufactured by Toray Industries, Inc., and Megana manufactured by Unitika Trading Co., Ltd.

[0057] In the brush manufacturing method, when a brush provided with a conductive polyester fiber material is used, the bristle height of the brush before the final process including heat treatment is not particularly limited. Preferred examples of the range of bristle height of the brush before the final process including heat treatment include the same range as the bristle height range of the brush described above. The bundle fineness and bundle density of the bristles of the brush before the final process including heat treatment are not particularly limited. Preferred examples of the range of bundle fineness of the bristles of the brush before the final process including heat treatment include the same range as the bundle fineness range of the brush bristles described above. Preferred examples of the range of bundle density of the bristles of the brush before the final process including heat treatment include the same range as the bundle density range of the bristles of the brush described above.

[0058] A method for manufacturing a woven fabric containing a conductive polyester fiber material may include fixing the fiber material to a base or weaving the conductive polyester fiber material into a base fabric. The method for weaving the conductive polyester fiber material into a base fabric is not particularly limited, and various known techniques, such as pile weaving and electrostatic flocking, may be used. When weaving the conductive polyester fiber material into the base fabric, a fiber bundle in which multiple strands of the conductive polyester fiber material are bundled may be prepared in advance, and the fiber bundle may be woven into the base fabric. When weaving the conductive polyester fiber material into the base fabric, it is preferable to weave the fiber bundle in which multiple strands of the conductive polyester fiber material are bundled into the base fabric in a loop shape. The fiber bundle may be a fiber bundle in which multiple strands of the conductive polyester fiber material are bundled without twisting, or a fiber bundle in which multiple strands of the conductive polyester fiber material are bundled and then twisted to form an integrated bundle. A conductive polyester fiber material or a fiber bundle formed by bundling a plurality of conductive polyester fiber materials into a base fabric in a loop shape may be woven into the base fabric, and then the tip of the fiber bundle may be cut to form a woven fabric in which the conductive polyester fiber material is woven into the base fabric in the form of straight fibers.

[0059] The method for manufacturing a brush using the manufactured woven fabric is not particularly limited, but may include, for example, attaching the woven fabric to a base. The method for attaching the woven fabric to the base preferably includes wrapping the woven fabric around the base. The method for fixing the fibers and / or fabric to the base is not particularly limited, but examples include methods for fixing the fibers and / or fabric to the base using double-sided tape and / or adhesive. Examples of the base include those similar to the examples of the base in the description of the brush structure above. Examples of the base cloth include those similar to the examples of the base cloth in the description of the brush structure above.

[0060] A preferred embodiment of a method for manufacturing a brush includes wrapping a fabric having a conductive polyester fiber material woven into a base around a base, fixing the fabric to the base to obtain an article, and performing a final step on the fibers in the obtained article, including heat treatment.

[0061] Preferably, the method for manufacturing a brush further includes slanting the brush bristles. The slanting method is not particularly limited, and a known slanting method may be used. The slanting method is not particularly limited, but examples include methods including the following steps (i) or (ii). In the following steps (i) or (ii), the rotation direction of the brush and / or metal brush roller is preferably clockwise or counterclockwise.

[0062] (i) A brush in which the fibers constituting the brush bristles are arranged so that the tips of the fibers (or fiber bundles) or the tips of the loops are directed in a generally radial direction from the central axis of a cylindrical or columnar base is placed in a cylinder having an inner diameter slightly smaller than the outer diameter of the brush. The cylinder containing the brush is then rotated for a certain period of time. The rotation of the cylinder containing the brush may be carried out while the brush is heat-treated, if necessary.

[0063] (ii) A metal brush roller, with countless metal needles arranged on its outer surface, is inserted into a brush in which the fibers constituting the brush bristles are arranged so that the tips of the fibers (or fiber bundles) or the tips of the loops are directed in a generally radial direction from the central axis of the cylindrical or cylindrical base. The amount of insertion is not particularly limited; it should be an amount that achieves the desired bristles. Then, with the metal brush roller inserted into the brush, the brush and metal brush roller are rotated. The brush and metal brush roller may be rotated while the brush is heat-treated, if necessary.

[0064] As another example of a slanting method, the fibers constituting the brush bristles may be disposed at an angle relative to the base fabric and / or the base so that the brush bristles are in a slanted state.

[0065] The final step including heat treatment preferably includes slanting the brush bristles. The final step including heat treatment is the final step including heat treatment in the method for manufacturing a brush using a woven fabric containing a conductive polyester fiber material, and more preferably includes slanting the brush bristles.

[0066] In one embodiment, the brush manufacturing method preferably further includes quenching the conductive polyester fiber material after the heat treatment in the final step including the heat treatment. In this specification, quenching refers to cooling at a temperature drop rate faster than natural cooling. The cooling rate during quenching is not particularly limited. The cooling rate during quenching is preferably greater than 5°C / sec, more preferably 10°C / sec or greater, and even more preferably 20°C / sec or greater. The cooling rate during quenching is preferably 60°C / sec or less. Preferred examples of the range of the cooling rate during quenching include greater than 5°C / sec and 60°C / sec or less, 10°C / sec or greater and 60°C / sec or less, and 20°C / sec or greater and 60°C / sec or less.

[0067] The quenching time is not particularly limited. The quenching time is preferably 10 seconds or more, more preferably 30 seconds or more, and even more preferably 1 minute or more. The quenching time is preferably 10 minutes or less, more preferably 5 minutes or less, and even more preferably 2 minutes or less. Preferred examples of the quenching time range include 10 seconds to 10 minutes, 30 seconds to 5 minutes, and 1 minute to 2 minutes. The quenching time is preferably longer than the time until the temperature of the conductive polyester fiber no longer exceeds the glass transition temperature of the conductive polyester fiber after quenching.

[0068] The method for quenching the conductive polyester fiber material is not particularly limited. For example, the conductive polyester fiber material may be immersed directly in a liquid (e.g., water). For example, the conductive polyester fiber material may be quenched by spraying mist onto the conductive polyester fiber material using a spray nozzle so that the mist comes into contact with the conductive polyester fiber material. For example, the conductive polyester fiber material may be quenched by blowing cold air onto the conductive polyester fiber material, and, if necessary, further suctioning the cold air. The conductive polyester fiber material may be quenched by a combination of two or more of these methods. A preferred quenching method involves spraying mist onto the conductive polyester fiber material using a spray nozzle so that the mist comes into contact with the conductive polyester fiber material, and more preferably, by spraying a quenching agent onto the conductive polyester fiber material. Quenching is preferably performed, for example, by a method involving continuously spraying a quenching agent onto the conductive polyester fiber material for the quenching time described above. The quenching agent spray is not particularly limited. Commercially available quenching agent sprays are not particularly limited, but examples include quenching agents YON-A Q-RAY QRA-S481 and LP Q-RAY QRK-560 manufactured by Sanhayato Corporation, and quenching agents Z-281, Z-285, and Z-286 manufactured by Hozan Corporation.

[0069] When quenching is performed by spraying mist from a spray nozzle so that the mist comes into contact with the conductive polyester fiber material, the distance between the part of the conductive polyester fiber material closest to the nozzle and the nozzle tip is not particularly limited. The distance between the part of the conductive polyester fiber material closest to the nozzle and the nozzle tip is preferably 1 cm or more, more preferably 5 cm or more, and even more preferably 10 cm or more. The distance between the part of the conductive polyester fiber material closest to the nozzle and the nozzle tip is preferably 50 cm or less, more preferably 30 cm or less, and even more preferably 20 cm or less. Preferred examples of the range of the distance between the part of the conductive polyester fiber material closest to the nozzle and the nozzle tip include, for example, 1 cm or more and 50 cm or less, 5 cm or more and 30 cm or less, and 10 cm or more and 20 cm or less.

[0070] The conductive polyester fiber material may be quenched in the form of a single conductive polyester fiber material. The conductive polyester fiber material may also be quenched in the form of a woven fabric manufactured using the conductive polyester fiber material. The quenching may also be performed after the woven fabric manufactured using the conductive polyester fiber material is attached to a base. Among these methods, the quenching of the conductive polyester fiber material is preferably performed after the woven fabric manufactured using the conductive polyester fiber material is attached to a base. In this case, the distance between the nozzle tip and the part of the conductive polyester fiber material closest to the nozzle is the distance between the brush surface (the surface of the brush bristles) and the nozzle tip. Quenching is preferably performed until the brush surface temperature (the temperature of the woven fabric surface) no longer exceeds the glass transition temperature of the conductive polyester fiber material due to heat conduction from the base (e.g., the core metal) after quenching. The glass transition temperature of the conductive polyester fiber material can be determined from the DSC curve in the second heating process measured using a differential scanning calorimeter. First, a first heating process is measured, in which the temperature is increased from 20°C to 300°C at a heating rate of 10°C / min. Next, after the first heating process, measurements are taken during a cooling process in which the sample is cooled from 300°C to 0°C at a cooling rate of 10°C / min. Then, after the cooling process, measurements are taken during a second heating process in which the sample is heated from 0°C to 300°C at a heating rate of 10°C / min. Based on the obtained DSC curve, an extension of the baseline before the rise of the first endothermic peak (i.e., the peak that appears on the lowest temperature side during the second heating process) during the second heating process is drawn, along with a tangent line showing the maximum slope between the rise of the first endothermic peak and the peak top of the first endothermic peak. The intersection of these lines is the glass transition temperature. The glass transition temperature of the conductive polyester fiber material can be measured using a differential scanning calorimeter (DSC7000X, manufactured by Hitachi High-Tech Science Corporation) similar to that used in the measurement method for the endothermic peak of polyester fiber in the Examples described below. Measurements can be performed by sealing 1.0 mg of the measurement sample (conductive polyester fiber material) in an aluminum pan. An empty aluminum pan can be used as a reference.When multiple types of conductive polyester fiber materials are used, in this evaluation, measurement samples are prepared for each type of conductive polyester fiber material, measurements are performed, and the characteristics of the endothermic peaks are determined for each type of conductive polyester fiber material.

[0071] (Brush use) The brush according to one embodiment is preferably used in an image forming apparatus that forms an image by electrophotography. The brush according to one embodiment is preferably used in an image forming apparatus that forms an image by electrophotography, such that the brush bristles are in sliding contact with a component provided in the image forming apparatus. The brush according to one embodiment is preferably used in an image forming apparatus that forms an image by electrophotography, such that the brush bristles are in sliding contact with a component provided in the image forming apparatus while the apparatus is rotating. In this embodiment, the component provided in the image forming apparatus that comes in sliding contact with the brush bristles preferably includes at least one component selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. In this embodiment, the component provided in the image forming apparatus that comes in sliding contact with the brush bristles is more preferably at least one component selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt, and is particularly preferably an image carrier. The image forming apparatus that can be equipped with the brush according to one embodiment is not particularly limited and may be a known image forming apparatus. The image forming apparatus is preferably, for example, a device described in the description of the image forming apparatus below.

[0072] The brush according to one embodiment is preferably a cleaning brush or a lubricant-coated brush, and more preferably a lubricant-coated brush. The lubricant is not particularly limited, and examples thereof include the lubricants described below. The lubricant is preferably a solid lubricant. The brush according to one embodiment is more preferably used in an image forming apparatus that forms images by electrophotography, such that the brush bristles and the solid lubricant are in sliding contact with each other while rotating. The brush according to one embodiment is more preferably used in an image forming apparatus that forms images by electrophotography, such that the brush bristles and a member provided in the image forming apparatus are in sliding contact with each other while rotating. In this embodiment, the member in sliding contact with the brush bristles (the member provided in the image forming apparatus) preferably includes at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. In this embodiment, the member in sliding contact with the brush bristles is more preferably at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt, and particularly preferably an image carrier. The brush according to one embodiment is particularly preferably used in an image forming apparatus that forms images by electrophotography, in a rotating state, so that the brush bristles, the image carrier, and the solid lubricant are in sliding contact with each other. In these embodiments in which the brush bristles and the solid lubricant are in sliding contact with each other, the image forming apparatus includes the solid lubricant.

[0073] By using the brush according to this embodiment for the above-mentioned purposes, an image forming apparatus equipped with the brush tends to be able to form images of higher quality.

[0074] <Image forming apparatus and manufacturing method thereof> Another aspect of the present invention can be said to relate to an image forming apparatus that forms an image by electrophotography, including the brush according to the above aspect. The image forming apparatus in which the brush according to the above aspect is installed is not particularly limited, and any known image forming apparatus may be used. An example of an image forming apparatus in which the brush according to the above aspect is installed is the following image forming apparatus (A) (also simply referred to as "apparatus (A)" in this specification). The apparatus (A) is an image forming apparatus that forms an image by electrophotography, including an image carrier, an intermediate transfer belt, and at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt. In the apparatus (A), a toner image is formed on the image carrier by electrophotography, and the intermediate transfer belt contacts the image carrier, transferring the toner image. In the apparatus (A), at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt is disposed downstream of the intermediate transfer belt and transfers the toner image to a recording medium (e.g., paper). An example of an image forming apparatus in which the brush according to the above embodiment is installed is the "AccurioPress C12000" (manufactured by Konica Minolta, Inc.).

[0075] In the image forming apparatus according to one embodiment, the brush according to the above aspect is preferably a lubricant-applied brush or a cleaning brush, and more preferably a lubricant-applied brush. In the image forming apparatus according to one embodiment, the brush according to the above aspect is preferably arranged such that, when rotating, the brush bristles are in sliding contact with at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. In the image forming apparatus according to one embodiment, the brush according to the above aspect is preferably arranged such that, when rotating, the brush bristles are in sliding contact with a solid lubricant. In the image forming apparatus according to one embodiment, the brush according to the above aspect is more preferably arranged such that, when rotating, the brush bristles are in sliding contact with a member provided in the image forming apparatus and a solid lubricant. In this embodiment, the member in sliding contact with the brush bristles (a member provided in the image forming apparatus) preferably includes at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. In the embodiment, the member in sliding contact with the brush bristles is more preferably at least one selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt, and is particularly preferably an image carrier.In the image forming apparatus according to one embodiment, it is particularly preferable that the brush according to the above aspect is arranged in a rotating state so that the brush bristles, the image carrier, and the solid lubricant are in sliding contact with each other.

[0076] Examples of image forming apparatuses according to a preferred embodiment include the following apparatuses (A1) to (A4). Of these, apparatus (A3) or apparatus (A4) is more preferred. In apparatus (A3), the components provided in the image forming apparatus preferably include at least one selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. In apparatus (A3), the components provided in the image forming apparatus are more preferably at least one selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt, and are particularly preferably an image carrier. Of these, apparatus (A4) is particularly preferred. Device (A1): In the device (A) described above, the brush according to the above embodiment is arranged in a rotating state with the brush bristles in sliding contact with at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. Device (A2): The device (A) described above further containing a solid lubricant, in which the brush according to the above embodiment is arranged in a rotating state with the brush bristles in sliding contact with the solid lubricant. Device (A3): In the device (A) described above, which further includes a solid lubricant, the brush according to the above aspect is arranged in a rotating state so that the brush bristles, a member provided in the image forming device, and the solid lubricant are in sliding contact with each other. Device (A4): In the device (A) described above, which further includes a solid lubricant, the brush according to the above embodiment is arranged in a rotating state with the brush bristles, the image carrier, and the solid lubricant in sliding contact with each other.

[0077] An image forming apparatus according to one embodiment will be described below with reference to the accompanying drawings. However, the image forming apparatus using the brush according to the above aspect and the image forming apparatus according to this aspect are not limited to the following embodiment and illustrated examples.

[0078] 1 is a schematic cross-sectional view showing the general configuration of an image forming apparatus according to an embodiment. As shown in FIG. 1, the image forming apparatus 1 includes a control unit 10, an operation panel 20, an image forming unit 30, and a paper feed / transport unit 40.

[0079] The control unit 10 includes a CPU (Central Processing Unit) and a memory, and performs various controls of the entire image forming apparatus 1 by the CPU executing a control program stored in the memory.

[0080] The operation panel 20 is equipped with a touch panel, a numeric keypad, a start button, a stop button, etc., and is used to input various settings related to the device, display the device status, and input various instructions.

[0081] The image forming unit 30 has image creating units 31Y, 31M, 31C, and 31K, an intermediate transfer belt 32, a cleaning device 33 for the intermediate transfer belt 32, a secondary transfer unit 34 (the secondary transfer belt in FIG. 1), a cleaning device 35 for the secondary transfer unit 34, and a fixing device 36.

[0082] The imaging units have components corresponding to each of the basic colors: yellow (Y), magenta (M), cyan (C), and black (K). Imaging unit 31Y has a component corresponding to yellow (Y). Imaging unit 31M has a component corresponding to magenta (M). Imaging unit 31C has a component corresponding to cyan (C). Imaging unit 31K has a component corresponding to black (K). Intermediate transfer belt 32 moves in a clockwise direction in the illustration (see arrow). The imaging units 31Y, 31M, 31C, and 31K are arranged in the order of most upstream, with imaging unit 31Y being the most upstream, followed by imaging unit 31M, imaging unit 31C, and imaging unit 31K, respectively.

[0083] Each of the image forming units 31Y, 31M, 31C, and 31K includes a photosensitive member (image carrier), a charging unit, an exposure unit, a developing unit, a cleaning unit, a lubricant supply unit, and a primary transfer unit (e.g., a primary transfer roller). The developing unit 314Y contains a yellow developer, the developing unit 314M contains a magenta developer, the developing unit 314C contains a cyan developer, and the developing unit 314K contains a black developer. The image forming units 31Y, 31M, 31C, and 31K are configured similarly, except for the colors of the toner images formed on the photosensitive members 311Y, 311M, 311C, and 311K. Therefore, the image forming unit 31Y will be described in detail, and descriptions of the image forming units 31M, 31C, and 31K will be omitted. The developer is not particularly limited, and known developers may be used. It is preferable to use a two-component developer as the developer. The two-component developer consists of a carrier and a toner. The carrier is not particularly limited, but may have a particle size of 15 μm or more and 100 μm or less, and a saturation magnetization of 10 emu / g or more and 80 emu / g or less. The toner is not particularly limited, but may have a particle size of 3 μm or more and 15 μm or less. The toner has a negative charging characteristic, and the average charge amount is not particularly limited, but may be, for example, -60 μC / g or more and -20 μC / g or less. The two-component developer may be, for example, a mixture of the carrier and toner so that the toner concentration is 4% by mass or more and 10% by mass or less, but the two-component developer is not limited thereto.

[0084] The intermediate transfer belt 32, which also functions as a toner carrier, is rotatably stretched by multiple rollers. The intermediate transfer belt 32 is not particularly limited, but may be, for example, a semiconductor belt made of polyimide with a thickness of 80 μm and a volume resistivity set to 8 LOG Ω·cm or more and 11 LOG Ω·cm or less. The multiple rollers stretching the intermediate transfer belt 32 include an opposing roller that forms a transfer nip with the secondary transfer unit described below. This opposing roller is not particularly limited, but may be made of, for example, nitrile rubber (NBR). In this case, the rubber hardness is not particularly limited, but may be, for example, 40° (Asker-C), and the volume resistivity is not particularly limited, but may be, for example, 8 LOG Ω.

[0085] The toner images formed by each image forming unit 31Y are sequentially transferred onto the surface of intermediate transfer belt 32 by the respective primary transfer units, and after being superimposed, are transferred onto paper 50 transported to the transfer position. Secondary transfer unit 34 contacts the back side of the paper at the transfer position and transfers the toner onto the front side of the paper. Paper 50 with the transferred full-color toner image is transported to downstream fixing device 36, where it is heated and pressurized, thereby forming a full-color image on paper 50.

[0086] Residual toner remaining on the intermediate transfer belt 32 without being transferred to the paper 50 is transported downstream and collected by a cleaning device 33 for the intermediate transfer belt 32. The cleaning device 33 includes, for example, a brush roller, a lubricant supply unit, one or more cleaning blades, and a housing that houses these. The residual toner on the intermediate transfer belt 32 is cleaned by the cleaning blade. Furthermore, a lubricant (lubricant) is applied to the surface of the intermediate transfer belt 32 by a lubricant supply unit. The lubricant supply unit in the cleaning device 33 may further include a brush roller. In one embodiment, the brush according to the above embodiment may be used as the brush roller in the cleaning device 33 and / or the brush roller in the lubricant supply unit in the cleaning device 33.

[0087] The paper feed conveyance unit 40 includes multiple paper feed trays 41 and paper feed paths 42 and 43. Multiple sheets of paper 50 are stacked in the paper feed tray 41, and the topmost sheet 50 is fed one by one. The paper feed conveyance unit 40 includes multiple pairs of transport rollers arranged along the paper feed paths 42 and 43 and a drive motor (not shown) for driving the transport rollers. The paper feed conveyance unit 40 conveys the paper 50 fed from the paper feed tray 41 to the transfer position of the secondary transfer unit 34 or to the fixing device 36 downstream thereof. The cleaning device 35 for the secondary transfer unit 34 includes, for example, one or more cleaning blades, a lubricant supply unit, a transport screw, and a storage case. The cleaning device 35 may further include a brush roller. The lubricant supply unit in the cleaning device 35 includes, for example, a brush roller, a lubricant (lubricant), and a support unit. In one embodiment, the brush according to the above embodiment may be used as the brush roller in the cleaning device 35 and / or the brush roller in the lubricant supply unit in the cleaning device 35.

[0088] When double-sided printing is performed, the paper 50 with an image formed on one side is transported to the double-sided paper transport path 43 located below. The paper 50 transported to this paper transport path 43 is turned over on a switchback path, and then rejoins the single-sided paper transport path 42, where an image is again formed on the other side of the paper 50 by the image forming unit 30.

[0089] 2 is a cross-sectional schematic diagram illustrating an example of the configuration of the main parts of the image forming unit 31Y. The image forming unit 31Y forms a yellow (Y) toner image on a photoconductor 311Y, which is an image carrier. For example, the image forming unit 31Y includes at least a photoconductor 311Y, a charging unit 312Y, an exposure unit 313Y (FIG. 1), a developing unit 314Y (FIG. 1), a primary transfer unit 315Y, a cleaning unit 316Y, and a lubricant supply unit 317Y. In the image forming unit 31Y, for example, the lubricant supply unit 317Y is disposed between the primary transfer unit 315Y and the cleaning unit 316Y around the photoconductor 311Y.

[0090] The specific configuration of the photoreceptor 311Y is not particularly limited. The photoreceptor refers to an electrophotographic photoreceptor configured by imparting at least one of the charge generation function and the charge transport function, which are essential for the configuration of an electrophotographic photoreceptor, to an organic compound. In this specification, the photoreceptor includes all known organic photoreceptors, such as photoreceptors configured from known organic charge generation materials or organic charge transport materials, and photoreceptors configured with a polymer complex that has the charge generation function and the charge transport function.

[0091] The charging unit 312Y serves to apply a uniform potential to the photoconductor 311Y. The charging unit 312Y is configured, for example, by a non-contact charging device. Examples of non-contact charging devices include a corona discharge type charger such as a scorotron.

[0092] The exposure unit 313Y (FIG. 1) exposes the photoconductor 311Y, which has been given a uniform potential by the charging unit 312Y, based on an image signal (yellow). As a result, an electrostatic latent image corresponding to the yellow image is formed in the exposure unit 313Y. The exposure unit 313Y may have, for example, light-emitting elements and imaging elements arranged in an array in the axial direction of the photoconductor 311Y. The light-emitting elements may include, for example, LEDs (Light Emitting Diodes). The exposure unit 313Y may have, for example, a laser optical system.

[0093] The developing unit 314Y (FIG. 1) includes, for example, a developing sleeve and a voltage application device. The developing sleeve has a built-in magnet. A yellow developer is stored inside the developing unit 314Y. The developing sleeve rotates while holding the developer. The voltage application device applies a DC and / or AC bias voltage between the developing sleeve and the photoconductor 311Y.

[0094] The primary transfer unit 315Y transfers the toner image formed on the photosensitive member 311Y onto the intermediate transfer belt 32 (FIG. 1), which is an endless belt. The primary transfer unit 315Y is disposed in contact with the intermediate transfer belt 32.

[0095] The lubricant supplying unit 317Y supplies (applies) a lubricant (lubricant 319Y described below) to the surface of the photoreceptor 311Y. The lubricant supplying unit 317Y is provided, for example, downstream of the primary transfer unit 315Y and upstream of the cleaning unit 316Y. The lubricant supplying unit 317Y may be located in another position, for example, downstream of the cleaning unit 316Y. The lubricant supplying unit 317Y has a brush roller 318Y, a solid lubricant 319Y, and a pressure spring 320Y. In one embodiment, the brush according to the above aspect is preferably used as the brush roller 318Y.

[0096] The brush roller 318Y applies a lubricant 319Y to the surface of the photoconductor 311Y. The type of lubricant 319Y is not particularly limited. The amount of penetration of the brush roller 318Y into the photoconductor 311Y is not particularly limited, but may be, for example, 0.5 mm or more and 1.5 mm or less. The rotational speed of the brush roller 318Y is not particularly limited, but may be, for example, a peripheral speed ratio of 0.3 to 1.5 with respect to the photoconductor 311Y. The rotational direction of the brush roller 318Y is not particularly limited, and may be the same as or opposite to the rotational direction of the photoconductor 311Y.

[0097] Pressure spring 320Y presses brush roller 318Y against photoconductor 311Y via lubricant 319Y. The pressing force of brush roller 318Y against photoconductor 311Y is not particularly limited, but pressure spring 320Y may press lubricant 319Y so as to be, for example, 0.5 N or more and 1.0 N or less.

[0098] In lubricant supply unit 317Y, the pressing force of lubricant 319Y against brush roller 318Y and the rotation speed of brush roller 318Y are adjusted, for example, to adjust the consumption amount of lubricant 319Y within a desired range. The consumption amount of lubricant 319Y per 1 km of cumulative length of the surface of photoreceptor 311Y is not particularly limited, but is preferably, for example, 0.04 g / km or more and 0.27 g / km or less, and more preferably 0.04 g / km or more and 0.15 g / km or less.

[0099] The cleaning unit 316Y includes a blade 321Y and a screw 322Y. The blade 321Y is a flat-plate-shaped member that contacts the surface of the photoreceptor 311Y to clean the surface of the photoreceptor 311Y. The blade 321Y has a flat-plate shape extending in the direction of the rotation axis of the photoreceptor 311Y. The blade 321Y contacts the surface of the photoreceptor 311Y in a counter-direction relative to the rotation direction of the photoreceptor 311Y. The blade 321Y presses against the surface of the photoreceptor 311Y to scrape off toner (residual toner) remaining on the surface of the photoreceptor 311Y after transfer. The residual toner scraped off from the surface of the photoreceptor 311Y is discharged to the outside of the image forming apparatus 1 by, for example, a screw 322Y. The cleaning unit 316Y may further include a rotating brush (brush roller), and the brush roller may scrape off the residual toner from the surface of the photoreceptor 311Y together with the blade 321Y. The brush according to the above embodiment may be used as the brush roller in the cleaning unit 316Y. Together with the blade 321Y, the brush roller 318Y in the lubricant supply unit 317Y may scrape off the remaining toner on the surface of the photoreceptor 311Y.

[0100] The above description has been given in detail of a case where the brush according to the above embodiment is used as the brush roller 318Y, and the brush bristles of the brush come into sliding contact with the image carrier while the brush according to the above embodiment is rotating. The above description has also been given in detail of a case where the brush roller 318Y is a lubricant application brush. However, in one embodiment, it is preferable to use the brush according to the above embodiment as a cleaning brush and / or a lubricant application brush in, for example, an imaging unit, a cleaning device for an intermediate transfer belt, and / or a cleaning device for a secondary transfer unit.

[0101] (lubricant) The image forming apparatus preferably contains a lubricant. The lubricant used in the image forming apparatus, such as the lubricant used in the lubricant supply unit of the imaging unit (e.g., lubricant 319Y), the lubricant used in the lubricant supply unit of the cleaning device 33, and / or the lubricant used in the lubricant supply unit of the cleaning device 35, is not particularly limited. Any known lubricant may be appropriately selected and used. The lubricant is preferably a solid lubricant (solid lubricant). In this specification, a solid lubricant refers to a lubricant that is solid at 80°C or below. The lubricant is not particularly limited, but examples thereof include fatty acid metal salts and fluorine-based resins. Specific examples of fatty acid metal salts include, but are not limited to, zinc laurate, barium stearate, lead stearate, iron stearate, nickel stearate, cobalt stearate, copper stearate, strontium stearate, calcium stearate, cadmium stearate, magnesium stearate, zinc stearate, aluminum stearate, indium stearate, potassium stearate, lithium stearate, sodium stearate, zinc oleate, magnesium oleate, iron oleate, cobalt oleate, copper oleate, lead oleate, manganese oleate, aluminum oleate, zinc palmitate, cobalt palmitate, lead palmitate, magnesium palmitate, aluminum palmitate, calcium palmitate, lead caprate, zinc linoleate, cobalt linoleate, calcium linoleate, zinc ricinoleate, and cadmium ricinoleate. The lubricant is preferably a metal salt of a fatty acid, more preferably a metal salt of a saturated or unsaturated fatty acid having 10 or more carbon atoms, and even more preferably zinc stearate. The lubricant may be used alone or in combination of two or more types.

[0102] (Image carrier) The image carriers used in the image forming apparatus according to one embodiment, such as photoreceptors 311Y, 311M, 311C, and 311K, are not particularly limited. Known photoreceptors may be appropriately selected and used as the image carriers. Examples of the photoreceptor include organic photoreceptors having a structure in which a charge generation layer and a charge transport layer are sequentially stacked on a conductive support. Preferred photoreceptors include, for example, organic photoreceptors having a structure in which a charge generation layer, a charge transport layer, and a protective layer are sequentially stacked on a conductive support. The photoreceptor preferably further includes an intermediate layer having barrier and adhesive properties between the conductive support and the charge generation layer. The conductive support, intermediate layer, charge generation layer, charge transport layer, and protective layer are not particularly limited, and known materials may be appropriately selected and used. Examples of conductive supports include supports formed by molding metal into a drum or sheet shape; supports formed by laminating metal foil onto a plastic film; supports formed by vapor-depositing metal or metal oxide onto a plastic film; and metal, plastic film, or paper provided with a conductive layer containing a conductive material. The intermediate layer may contain, for example, a binder resin, and may further contain various conductive particles or metal oxide particles in addition to the binder resin for the purpose of adjusting resistance. The charge generation layer preferably contains, for example, a charge generation material and a binder resin. The charge transport layer preferably contains, for example, a charge transport material and a binder resin. The protective layer preferably contains at least a resin component obtained by curing a polymerizable compound. The polymerizable compound is not particularly limited, but examples include monomers that polymerize (cure) upon exposure to actinic rays such as ultraviolet rays or electron beams to form resins commonly used as binder resins for photoreceptors. The protective layer preferably contains, in addition to the resin component, metal oxide particles and / or an electron transport compound that transports charge carriers. The conductive support, intermediate layer, charge generating layer, charge transport layer and protective layer may each further contain components other than those listed above.

[0103] (Toner and Developer) The developer contained in the developing units used in the image forming apparatus according to an embodiment, such as developing units 314Y, 314M, 314C, and 314K, is not particularly limited. The developer may be appropriately selected from known developers. In the image forming apparatus according to an embodiment, the toner (toner for developing electrostatic latent images) may be used as a magnetic or non-magnetic one-component developer, or may be mixed with a carrier and used as a two-component developer.

[0104] The toner is not particularly limited. The toner contains toner base particles. Preferably, the toner further contains an external additive. Known toner base particles may be appropriately selected and used as the toner base particles. The toner base particles contain at least a binder resin. The toner base particles may further contain other components such as a colorant, a release agent, and / or a charge control agent, as necessary. The binder resin, colorant, release agent, charge control agent, and other components are not particularly limited, and known components may be appropriately selected and used. Examples of binder resins include thermoplastic resins. Specific examples of binder resins include styrene-based resins; acrylic resins such as alkyl acrylates and alkyl methacrylates; styrene-acrylic copolymer resins; polyester resins; silicone resins; olefin-based resins; amide resins; and epoxy resins. Examples of colorants include known inorganic colorants and known organic colorants. Specific examples of colorants include carbon black. Examples of release agents include hydrocarbon waxes such as polyethylene wax, oxidized polyethylene wax, polypropylene wax, and oxidized polypropylene wax; carnauba wax; fatty acid ester wax; sazol wax; rice wax; candelilla wax; jojoba oil wax; and beeswax. Examples of charge control agents include zinc or aluminum metal complexes of salicylic acid derivatives (salicylic acid metal complexes); calixarene compounds; organic boron compounds; and fluorine-containing quaternary ammonium salt compounds. Examples of external additives include, but are not limited to, fatty acid metal salt particles, inorganic fine particles, and organic fine particles. The fatty acid metal salt particles, inorganic fine particles, and organic fine particles are not particularly limited, and known particles may be used. Examples of fatty acid metal salt particles include, but are not limited to, zinc stearate particles, lithium stearate particles, and magnesium stearate particles. Examples of inorganic fine particles include, but are not limited to, silica particles, titania particles, and alumina particles. The inorganic particles may be surface-treated with, for example, a silane coupling agent, a titanium coupling agent, a higher fatty acid, or a silicone oil.The organic fine particles are not particularly limited, but examples thereof include polystyrene particles, polymethyl methacrylate particles, and styrene-methyl methacrylate copolymer particles.

[0105] When a toner for developing electrostatic latent images is used as a two-component developer, the carrier is not particularly limited, and magnetic particles made of known materials can be used. Examples of such known materials include, but are not limited to, metals such as iron, ferrite, and magnetite; alloys of these metals with metals such as aluminum and / or lead; and the like. Examples of carriers include, but are not limited to, resin-coated carriers (coated carriers) in which the surfaces of magnetic particles are coated with a coating agent such as a resin, and binder-type carriers in which magnetic fine powder is dispersed in a binder resin. Examples of coating resins that constitute resin-coated carriers include, but are not limited to, olefin-based resins, styrene-based resins, styrene-acrylic resins, acrylic resins, silicone-based resins, ester resins, and fluororesins. Examples of binder resins that constitute binder-type carriers include, but are not limited to, styrene-acrylic resins, polyester resins, fluororesins, and phenolic resins.

[0106] Another aspect of the present invention relates to a method for manufacturing an image forming apparatus for forming an image by electrophotography, including manufacturing a brush and incorporating the brush into the image forming apparatus. The method for manufacturing the brush includes one or more steps including heat-treating a conductive polyester fiber material, and the final step of the one or more steps preferably includes heat-treating the conductive polyester fiber material at a temperature of 155°C to 190°C. By heat-treating the conductive polyester fiber material in the final step including heat treatment, the conductive polyester fiber material can become conductive polyester fiber (I). Details of the brush and its manufacturing method, as well as the image forming apparatus, in the method for manufacturing an image forming apparatus according to one embodiment are as described above.

[0107] Although the embodiments of the present invention have been described in detail, it is clear that this is for illustrative and exemplary purposes only and not for limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0108] The present invention encompasses the following aspects and configurations: [1] Includes brush bristles. the brush bristles comprise conductive polyester fibers having, in a DSC curve measured with a differential scanning calorimeter in a temperature range of 20°C to 300°C at a temperature increase rate of 10°C / min, a main endothermic peak which is an endothermic peak at which the amount of heat absorbed is maximum, and an endothermic subpeak having a peak top in a range of 155°C to 190°C in the DSC curve; A brush used in an image forming apparatus that forms an image by electrophotography. [2] The brush according to [1], wherein the temperature at the endothermic subpeak minus the temperature at the peak start point is 40°C or less. [3] The brush according to [1] or [2], wherein the endothermic subpeak has a peak top in the region of 160°C or higher and 190°C or lower. [4] The brush according to any one of [1] to [3], wherein the value obtained by subtracting the temperature at the peak start position from the temperature at the peak end position of the endothermic subpeak is 35°C or less. [5] The brush according to any one of [1] to [4], which is a straight-bristle brush. [6] The brush according to any one of [1] to [5], which is a brush with slanted bristles. [7] In the image forming apparatus, the brush bristles are used so as to be in sliding contact with a member provided in the image forming apparatus while the apparatus is rotating, The brush according to any one of [1] to [6], wherein the member includes at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt. [8] The brush according to any one of [1] to [7], which is used in the image forming apparatus such that the brush bristles and a solid lubricant are in sliding contact with each other in a rotating state. [9] comprising one or more steps including heat treating the conductive polyester fiber material; The final step of the one or more steps includes heat treating the conductive polyester fiber material at a temperature of 155°C or higher and 190°C or lower. A method for manufacturing a brush according to any one of [1] to [8] above.

[10] An image forming apparatus for forming an image by an electrophotographic method, comprising the brush according to any one of [1] to [8] above.

[11] The image forming apparatus is an image carrier on which a toner image is formed by an electrophotographic method; an intermediate transfer belt that contacts the image carrier and onto which the toner image is transferred; at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt, which is disposed downstream of the intermediate transfer belt and transfers the toner image onto a recording medium; further comprising the brush is arranged in a rotating state so that the brush bristles are in sliding contact with at least one member selected from the group consisting of the image carrier, the intermediate transfer belt, the secondary transfer roller, and the secondary transfer belt; The image forming apparatus according to

[10] above.

[12] The image forming apparatus is an image carrier on which a toner image is formed by an electrophotographic method; an intermediate transfer belt that contacts the image carrier and onto which the toner image is transferred; at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt, which is disposed downstream of the intermediate transfer belt and transfers the toner image onto a recording medium; A solid lubricant; further comprising The brush is arranged in a rotating state so that the brush bristles and the solid lubricant are in sliding contact with each other. The image forming apparatus according to

[10] or

[11] above. [Example]

[0109] The effects of the present invention will be explained using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Furthermore, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively.

[0110] <Brush manufacturing> Example 1 A strip of fabric 1, consisting of a 0.5 mm thick base fabric with polyester fiber bundles woven with a pile length of 3.0 mm, was spirally wound around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm and fixed with an adhesive to obtain a brush before heat treatment. The obtained brush was then heat-treated for 1 minute at 160°C in a drying oven, and then removed from the oven and allowed to cool naturally to produce brush 1 with an outer diameter of 15 mm.

[0111] [Textile 1] Fiber: Polyester fiber (product name: Belltron (registered trademark) BR-1, manufactured by KR Seiren Co., Ltd., single fiber fineness 4.4 decitex, surface resistance 10 10 Ω / cm) Fiber shape: Straight Bundle size: 210 decitex Flux density: 150kF / inch 2 Pile length: 3.0mm.

[0112] Example 2 A brush 2 having an outer diameter of 15 mm was manufactured in the same manner as in Example 1, except that the heat treatment time was set to 7 minutes.

[0113] Example 3 A strip of fabric 2, consisting of a 0.5 mm thick base fabric and 3.0 mm woven polyester fiber bundles, was spirally wound around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm and fixed with an adhesive to obtain a brush before heat treatment. The resulting brush was then heat-treated for 5 minutes at 170°C in a drying oven, after which it was removed from the oven and allowed to cool naturally to produce a brush 3 with an outer diameter of 15 mm.

[0114] [Textile 2] Fiber: Polyester fiber (product name: Belltron (registered trademark) BR-1, manufactured by KR Seiren Co., Ltd., single fiber fineness 4.4 decitex, surface resistance 10 10 Ω / cm) Fiber shape: Loop Bundle size: 210 decitex Flux density: 150kF / inch 2 Bristle height: 3.0mm.

[0115] Example 4 The above-mentioned strip-shaped woven fabric 1, which was made of a 0.5 mm thick base fabric woven with polyester fiber bundles at a pile length of 3.0 mm, was spirally wound around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm and fixed with an adhesive to obtain a brush before heat treatment. The obtained brush was then heat-treated for 5 minutes at a temperature of 180°C in a drying oven, and then removed from the oven and rapidly cooled to produce brush 4 with an outer diameter of 15 mm.

[0116] The brush was removed from the drying oven and quenched by spraying a commercially available quenching agent spray (Quenching Agent Z-286, manufactured by Hozan Corporation) onto the brush for 1 minute at a cooling rate of approximately 40°C / sec, with the nozzle tip held 15 cm away from the brush surface.

[0117] Example 5 A strip of fabric 3, consisting of a 0.5 mm thick base fabric and polyester fiber bundles woven with a pile length of 4.0 mm, was spirally wound around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm and fixed with adhesive to obtain a brush before heat treatment. The resulting brush was then inserted into a metal cylinder with an inner diameter of 15 mm to tilt the polyester fibers. The brush was then heat-treated for 5 minutes at 180°C while the metal cylinder with the brush inserted was rotated. After heat treatment, the brush was removed from the metal cylinder and rapidly cooled to produce a brush 5 with an outer diameter of 15 mm.

[0118] The quenching was carried out by spraying a commercially available quenching agent spray (Quenching Agent Z-286 manufactured by Hozan Corporation) onto the brush removed from the metal cylinder for 1 minute at a cooling rate of approximately 40°C / sec, with the nozzle tip held 15 cm away from the brush surface.

[0119] The bristle height of the brush 5 was 3.0 mm.

[0120] [Textile 3] Fiber: Polyester fiber (product name: Kuracarbo, manufactured by Kuraray Trading Co., Ltd., single fiber fineness 3.3 decitex, surface resistance 10 8 Ω / cm) Fiber shape: Straight Bundle size: 230 decitex Flux density: 210kF / inch 2 Pile length: 4.0mm.

[0121] Example 6 A strip of fabric 4, consisting of a 0.5 mm thick base fabric with polyester fiber bundles woven with a pile length of 3.0 mm, was spirally wound around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm and fixed with an adhesive to obtain a brush before heat treatment. The obtained brush was then heat-treated for 5 minutes at 190°C in a drying oven, after which it was removed from the oven and allowed to cool naturally to produce a brush 6 with an outer diameter of 15 mm.

[0122] [Textile 4] Fiber: Polyester fiber (product name: SCIMA, manufactured by Toray Industries, Inc., single fiber fineness 3.1 decitex, surface resistance 10 8 Ω / cm) Fiber shape: Straight Bundle size: 220 decitex Flux density: 225kF / inch 2 Pile length: 3.0mm.

[0123] (Comparative Example 1) A brush 7 having an outer diameter of 15 mm was manufactured in the same manner as in Example 1, except that the temperature and time of the heat treatment were 140° C. and 5 minutes.

[0124] (Comparative Example 2) A brush 8 having an outer diameter of 15 mm was manufactured in the same manner as in Example 1, except that the temperature and time of the heat treatment were set to 200° C. and 7 minutes.

[0125] (Comparative Example 3) A brush 9 with an outer diameter of 15 mm was manufactured by spirally wrapping a strip of fabric 1, which was made of a 0.5 mm thick base fabric woven with polyester fiber bundles at a pile length of 3.0 mm, around a stainless steel (SUS) shaft with an outer diameter of 8 mm and a length of 422 mm, and fixing it with adhesive.

[0126] Table 1 shows the characteristics of the fabrics used to manufacture each brush and the heat treatment conditions.

[0127] In fabrics 1, 3, and 4, the polyester fibers (fiber bundles) were arranged upright relative to the base fabric, and in fabric 2, the loops were arranged upright relative to the base fabric. The bristles of manufactured brushes 1 to 4 and 6 to 9 were upright, and the bristles of manufactured brush 5 were inclined.

[0128] The fibers in the manufactured brushes 1, 2, and 4 to 9 were straight. The fibers in the manufactured brush 3 were looped. The bristle heights and outer diameters of the manufactured brushes 1 to 9 are shown in Table 2.

[0129] <Conductivity of polyester fiber materials> Polyester fibers were removed from the above woven fabrics 1 to 4 and left overnight or longer in an environment at a temperature of 23°C and a relative humidity of 50%RH. Thereafter, the surface resistance value [Ω / cm] of the polyester fibers was measured in an environment at a temperature of 23°C and a relative humidity of 50%RH. The surface resistance value was measured using a probe consisting of two rod terminals (diameter φ2 mm, distance between the rod terminals 20 mm) connected to an insulation resistance meter SM-8220 manufactured by Hioki E.E. Corporation, under the condition of an applied voltage of 100V.

[0130] In this evaluation, the surface resistance of polyester fiber was measured at 10°C under a temperature of 23°C and a relative humidity of 50%. 12 When the resistivity was Ω / cm or less, the polyester fiber was determined to be a conductive polyester fiber.

[0131] Furthermore, the surface resistance values ​​of the polyester fibers used in the manufacture of brushes 1 to 8 after heat treatment under the heat treatment conditions used in the manufacture of these brushes were similar to the above values ​​shown as the surface resistance values ​​of the polyester fibers used in the manufacture of these brushes.

[0132] <Evaluation of Brushes and Image Forming Devices> (Endothermic peak of polyester fiber) The endothermic peaks of the polyester fibers of brushes 1 to 9 produced above were confirmed from DSC curves measured using a differential scanning calorimeter "DSC7000X" (manufactured by Hitachi High-Tech Science Corporation). Specifically, polyester fibers were removed from the brushes produced above, and the polyester fibers were used as measurement samples. 1.0 mg of the measurement sample (polyester fibers) was sealed in an aluminum pan and set in the sample holder of the differential scanning calorimeter "DSC7000X." An empty aluminum pan was used as a reference. Then, a DSC curve was obtained by increasing the temperature from 20°C to 300°C at a heating rate of 10°C / min in temperature modulation mode.

[0133] Based on the obtained DSC curve, an extension of the baseline before the onset of each endothermic peak was drawn. The area connecting the extension of the baseline and the next common point with the DSC curve (the next common point between the extension of the baseline and the DSC curve in the direction from the low temperature side to the high temperature side or from the high temperature side to the low temperature side) was defined as the endothermic amount [mJ / mg]. The baseline extension was drawn for each endothermic peak by extending the baseline from a position 5°C lower than the onset position of the DSC curve peak.

[0134] The peak top temperature was then confirmed for each endothermic peak. For each endothermic peak, the temperature at the rising point of the peak was taken as the peak start temperature. For each endothermic peak, the temperature at the next common point between the extension of the baseline and the DSC curve (the next common point between the extension of the baseline and the DSC curve in the direction from the low temperature side to the high temperature side or from the high temperature side to the low temperature side) was taken as the peak end temperature.

[0135] In the obtained DSC curve, the endothermic peak with the largest endothermic amount was designated the main endothermic peak, and the endothermic peak different from the main endothermic peak was designated the sub-endothermic peak. The endothermic amount of the main endothermic peak and the peak-top temperature of the main endothermic peak are shown in Table 2. Table 2 also shows the endothermic amount of the endothermic sub-peak, the peak-top temperature of the endothermic sub-peak, the temperature at the peak start position of the endothermic sub-peak, the peak completion position of the endothermic sub-peak, and the peak width of the endothermic sub-peak (the temperature at the peak completion position minus the temperature at the peak start position).

[0136] (Brush pressure) The pressing force of brushes 1 to 9 was evaluated using a commercially available load cell "ULA100GR" (manufactured by MinebeaMitsumi Inc.). More specifically, the brush was rotated clockwise at 60 rpm (1 s) while the measuring terminal 101 shown in FIG. 3 was pressed against the surface of the brush manufactured above. -1) The brush was rotated at a speed of 1000 kJ / s. The load cell's measuring terminal was pressed in 0.8 mm from the outer diameter of the brush. The force (load) received by the brush on the measuring terminal surface while the brush was rotating was measured three times, and the average value was taken as the brush pressing force [mN / cm].

[0137] In this evaluation, the brush 5, which is a brush with slanted bristles, was measured by setting the bristles in a direction in which the tips of the bristles were inclined in the opposite direction from the roots to the upstream side in the direction of travel.

[0138] The brush pressure was evaluated according to the following criteria. In this evaluation, a pressure of 40 mN / cm or more was judged to be practically preferable. The brush pressure is shown in Table 3.

[0139] <Evaluation Criteria> A: The pressure is 45 mN / cm or more; B: The pressing force is 40 mN / cm or more and less than 45 mN / cm; C: The pressing force is less than 40 mN / cm.

[0140] 3 is a schematic diagram illustrating a method for measuring the pressing force that a member that is in sliding contact with the brush receives from the brush when the brush rotates. In this measurement, the measurement terminal 101 of the load cell 100 was pressed against the bristles of the rotating brush 102. Then, with the bristles of the rotating brush 102 pressed against the surface of the measurement terminal 101 of the load cell 100, the rotating brush 102 was rotated to measure the force with which the bristles of the rotating brush 102 push back against the measurement terminal 101.

[0141] (Image density unevenness) Image forming apparatuses were prepared in which the brush rollers (rotating brushes) provided in the lubricant supply sections of all drum units of a commercially available image forming apparatus "AccurioPress C12000" (manufactured by Konica Minolta, Inc.) were replaced with the brushes 1 to 9 manufactured above. Images were evaluated using these image forming apparatuses.

[0142] The lubricant supply section of all drum units of the commercially available image forming apparatus "AccurioPress C12000" (manufactured by Konica Minolta, Inc.) is equipped with a solid lubricant (solid lubricant), and the same solid lubricant was used in the image forming apparatus used for image evaluation.

[0143] The evaluation was carried out in an environment of 10°C and 20% relative humidity (LL environment), by continuously printing 10,000 sheets of a pattern image (the width of the solid image area and each non-image area was 1 / 3 of the paper width) on both sides of an A3 size sheet of paper, with a 100% cyan solid image area in the center of the paper in the conveyance direction and non-image areas (blank areas) on either side of it. Immediately after forming the pattern image, the image was printed on POD gloss coated paper (basis weight 128 g / m 2 A 40% green halftone image (image density: yellow 40%, cyan 40%) was printed on a paper feeder (manufactured by Oji Paper Co., Ltd.) and used as the evaluation image. Before outputting the evaluation image, the yellow drum unit was replaced, and a genuine new drum unit from the commercially available image forming device was used as the yellow drum unit used when outputting the evaluation image.

[0144] The obtained evaluation images were checked for the presence and extent of image density unevenness in the areas corresponding to the boundaries between the solid image areas and the blank areas in the pattern image, and were judged according to the following criteria. The judgment of image density unevenness was made for each of the areas corresponding to the two boundaries in the pattern image, and the evaluation was based on the average score. For example, if the area corresponding to one boundary in the pattern image was rated 4 points and the area corresponding to the other boundary was rated 3 points, the evaluation result was 3.5 points. In this evaluation, a score of 3 points or more was considered to be practically preferable. The evaluation results of image density unevenness are shown in Table 3.

[0145] <Evaluation criteria for each of the two boundary areas in the pattern image> 4 points: No difference in image density is observed at the boundary between the solid image area and the blank area; 3 points: Slight streaks are visible in the area corresponding to the boundary between the solid image area and the white paper area, and a slight difference in image density is visible in part of the area corresponding to the boundary between the solid image area and the white paper area; 2 points: Stripes are visible throughout the area corresponding to the boundary between the solid image area and the white paper area, and a difference in image density is observed in the area corresponding to the boundary between the solid image area and the white paper area; 1 point: Streaks are visible throughout the area corresponding to the boundary between the solid image area and the blank area, and there is an image density difference throughout the area corresponding to the boundary between the solid image area and the blank area that is easily detectable even when measuring the reflection density with a Macbeth densitometer.

[0146] <Evaluation criteria for image density unevenness> A: The average score of the evaluation results for the two boundaries in the pattern image is 3 points or more; B: The average score of the evaluation results for the areas corresponding to the two boundaries in the pattern image is less than 3 points.

[0147] [Table 1]

[0148] [Table 2]

[0149] [Table 3]

[0150] The results in Tables 1 to 3 confirm that the brushes according to the examples of the present invention are excellent in both brush pressing force and image density unevenness. On the other hand, the brushes according to the comparative examples, which are outside the scope of the present invention, are inferior in at least one evaluation result selected from the group consisting of brush pressing force and image density unevenness. These results confirm that the brushes according to the present invention can obtain sufficient pressing force. Furthermore, it was confirmed that the brushes according to the examples of the present invention, when used in an image forming apparatus, can reduce image density unevenness and achieve high image quality. On the other hand, the brushes according to the comparative examples, which are outside the scope of the present invention, are inferior in at least one evaluation result selected from the group consisting of brush pressing force and image density unevenness.

[0151] It is known that uneven lubricant application can cause variations in the amount of charge on the image carrier surface, depending on the thickness of the lubricant layer caused by the uneven application. This can lead to potential variations on the image carrier, resulting in uneven image density in the printed image. This unevenness is particularly pronounced when forming halftone images in the intermediate density range. Therefore, if changing the type of brush in the lubricant supply unit of the image forming apparatus changes the presence and degree of uneven image density in the evaluation image, as in the above evaluation, it is assumed that the unevenness of the lubricant application has changed depending on the type of brush. Furthermore, when the evaluation of image density unevenness is better in the above evaluation, it is assumed that the unevenness of the lubricant application is smaller, and therefore that the stability of the brush's abrasive force is higher.

[0152] While embodiments of the present invention have been described and illustrated in detail, the disclosed embodiments are made for purposes of illustration and example only and are not intended to be limiting, and the scope of the present invention should be construed by the language of the appended claims. [Explanation of symbols]

[0153] 1. Image forming device 10 Control Unit 20 Operation Panel 30 Image forming unit 31Y, 31M, 31C, 31K Imaging section 311Y, 311M, 311C, 311K photoreceptor 312Y, 312M, 312C, 312K charging unit 313Y, 313M, 313C, 313K exposure section 314Y, 314M, 314C, 314K developing section 315Y, 315M, 315C, 315K Primary Transfer Unit 316Y, 316M, 316C, 316K cleaning unit 317Y, 317M, 317C, 317K Lubricant supply section 318Y Rotating Brush (Brush Roller) 319Y Solid lubricant (solid lubricant) 320Y pressure spring 321Y Blade 322Y screw 32 Intermediate transfer belt 33 Cleaning device (for intermediate transfer belt) 34 Secondary transfer unit 35 Cleaning device (for secondary transfer section) 36 Fixing device 40 Paper feed transport section 41 Paper tray 42, 43 Paper transport path 50 sheets 100 load cells 101 Measurement terminal 102 Rotating brush.

Claims

1. Includes brush bristles, the brush bristles contain conductive polyester fibers having, in a DSC curve measured with a differential scanning calorimeter in a range of 20°C to 300°C at a temperature increase rate of 10°C / min, a main endothermic peak which is an endothermic peak at which the amount of heat absorbed is maximum, and an endothermic subpeak having a peak top in a range of 155°C to 190°C in the DSC curve; A brush used in an image forming apparatus that forms an image by electrophotography.

2. 2. The brush of claim 1, wherein the temperature at the endothermic sub-peak minus the temperature at the peak start is 40°C or less.

3. The brush according to claim 1 , wherein the endothermic subpeak has a peak top in a region of 160° C. or higher and 190° C. or lower.

4. 2. The brush of claim 1, wherein the temperature at the endothermic sub-peak minus the temperature at the peak start is 35[deg.] C. or less.

5. 10. The brush of claim 1, which is a straight-bristle brush.

6. 2. The brush according to claim 1, wherein the brush is a slanted brush.

7. In the image forming apparatus, the brush bristles are used so as to come into sliding contact with members provided in the image forming apparatus while the apparatus is rotating, The brush according to claim 1 , wherein the member comprises at least one member selected from the group consisting of an image carrier, an intermediate transfer belt, a secondary transfer roller, and a secondary transfer belt.

8. 2. The brush according to claim 1, wherein the brush is used in the image forming apparatus such that the brush bristles and the solid lubricant are in sliding contact with each other in a rotating state.

9. one or more steps including heat treating the conductive polyester fiber material; The final step of the one or more steps includes heat treating the conductive polyester fiber material at a temperature of 155°C or higher and 190°C or lower. A method for manufacturing the brush according to any one of claims 1 to 8.

10. An image forming apparatus for forming an image by an electrophotographic method, comprising the brush according to any one of claims 1 to 8.

11. the image forming apparatus, an image carrier on which a toner image is formed by an electrophotographic method; an intermediate transfer belt that contacts the image carrier and onto which the toner image is transferred; at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt, which is disposed downstream of the intermediate transfer belt and transfers the toner image onto a recording medium; further comprising the brush is arranged in a rotating state so that the brush bristles are in sliding contact with at least one member selected from the group consisting of the image carrier, the intermediate transfer belt, the secondary transfer roller, and the secondary transfer belt; The image forming apparatus according to claim 10.

12. the image forming apparatus, an image carrier on which a toner image is formed by an electrophotographic method; an intermediate transfer belt that contacts the image carrier and onto which the toner image is transferred; at least one member selected from the group consisting of a secondary transfer roller and a secondary transfer belt, which is disposed downstream of the intermediate transfer belt and transfers the toner image onto a recording medium; A solid lubricant; further comprising The brush is arranged in a rotating state so that the brush bristles and the solid lubricant are in sliding contact with each other. The image forming apparatus according to claim 10.

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