Image forming apparatus and process cartridge

Abstract

To provide an image forming apparatus that prevents a deterioration in transferability to a recording medium with large irregularities on a surface.SOLUTION: An image forming apparatus comprises: an electrophotographic photoreceptor; electrifying means that electrifies a surface of the electrophotographic photoreceptor; electrostatic charge image forming means that forms an electrostatic charge image on the electrified surface of the electrophotographic photoreceptor; developing means that stores an electrostatic charge image developer including toner for electrostatic charge image development, and develops the electrostatic charge image formed on the surface of the electrophotographic photoreceptor with the electrostatic charge image developer as a toner image; transfer means that transfers the toner image formed on the surface of the electrophotographic photoreceptor to a surface of a recording medium; and cleaning means that has a cleaning blade that is in contact with the surface of the electrophotographic photoreceptor to clean the surface of the electrophotographic photoreceptor, wherein the toner for electrostatic charge image development has a solid lubricant including a fatty acid metal salt and an antioxidant, and / or application means that applies a solid lubricant including a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor is provided.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an image forming apparatus and a process cartridge.

Background Art

[0002] Patent Document 1 discloses an image forming apparatus including an image carrier and a developing device that develops an electrostatic latent image formed on the image carrier, wherein fine particles of a lubricant are dispersed in a surface layer of the image carrier, and a lubricant is added to a developer used in the developing device.

[0003] Patent Document 2 discloses an electrophotographic image forming method in which an electrostatic latent image is formed on a photoreceptor, the electrostatic latent image is visualized using toner, and then the toner image is transferred and fixed onto a medium to obtain a visible image, the method having a cleaning step of removing residual transfer toner on the photoreceptor, wherein in the cleaning step, a blade cleaning method using a cleaning blade which is a plate-like elastic body for removing residual transfer toner on the photoreceptor, and a loss tangent tanδ of the cleaning blade at 10°C to 30°C is 0.2 or less, and a liquid lubricant is applied onto the photoreceptor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] The objective is to provide an image forming apparatus comprising an electrophotographic photoreceptor, a charging means, an electrostatic image forming means, a developing means for developing an electrostatic image using a contained electrostatic image developing toner, a transfer means, and a cleaning means having a cleaning blade, which suppresses deterioration of transferability to recording media with large surface irregularities compared to cases where the electrostatic image developing toner contains a solid lubricant containing only a fatty acid metal salt, or where a coating means is provided for applying a solid lubricant containing only a fatty acid metal salt onto the electrophotographic photoreceptor. [Means for solving the problem]

[0006] The following embodiments are included as specific means for solving the aforementioned problems.

[0007] <1> An electrophotographic photoreceptor having a photosensitive layer, A charging means for charging the surface of the electrophotographic photoreceptor, A means for forming an electrostatic image on the surface of the charged electrophotographic photoreceptor, A developing means containing an electrostatic image developer including an electrostatic image developing toner, and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the electrostatic image developer, A transfer means for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, An image forming apparatus comprising and satisfying at least one of the following conditions (1) and (2). Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor.

[0008] <2> The antioxidant comprises one or more selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. <1> The image forming apparatus described above. <3> The antioxidant comprises a phenolic antioxidant and one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants. <1> The image forming apparatus described above. <4> The antioxidant comprises the phenolic antioxidant and the sulfuric antioxidant. <3> The image forming apparatus described above. <5> The content of the antioxidant in the solid lubricant is 1% by mass or more and 50% by mass or less, relative to the total mass of the solid lubricant. <1> ~ <4> An image forming apparatus as described in any one of the following. <6> The aforementioned antioxidant includes a phenolic antioxidant, The content of the phenolic antioxidant is 5% by mass or more and 100% by mass or less, relative to the total mass of the antioxidant. <5> The image forming apparatus described above.

[0009] <7> A developing means that contains an electrostatic image developer containing an electrostatic image developing toner, and develops the electrostatic image formed on the surface of an electrophotographic photoreceptor as a toner image using the electrostatic image developer, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, A process cartridge that is equipped with and satisfies at least one of the following conditions (1) and (2), and is detachable from an image forming apparatus. Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor. [Effects of the Invention]

[0010] According to the invention according to <1> or <6>, there is provided an image forming apparatus including an electrophotographic photoreceptor, charging means, electrostatic charge image forming means, developing means for developing an electrostatic charge image using the contained toner for developing an electrostatic charge image, transfer means, and cleaning means having a cleaning blade, wherein the toner for developing an electrostatic charge image has a solid lubricant containing only a fatty acid metal salt, or compared with the case of including coating means for coating a solid lubricant containing only a fatty acid metal salt on the electrophotographic photoreceptor, deterioration of transferability to a recording medium having large surface irregularities is suppressed. According to the invention according to <2> or <3>, there is provided an image forming apparatus that suppresses deterioration of transferability to a recording medium having large surface irregularities as compared with the case where only a hindered amine-based antioxidant is used as an antioxidant in a solid lubricant. According to the invention according to <4>, there is provided an image forming apparatus that suppresses deterioration of transferability to a recording medium having large surface irregularities as compared with the case where a phenolic antioxidant and a phosphorus-based antioxidant or a hindered amine-based antioxidant are used in combination as antioxidants in a solid lubricant. According to the invention according to <5>, there is provided an image forming apparatus that suppresses deterioration of transferability to a recording medium having large surface irregularities as compared with the case where the content of the antioxidant is less than 5% by mass or more than 50% by mass with respect to the mass of the fatty acid metal salt. According to the invention according to <7>, there is provided a process cartridge including an electrophotographic photoreceptor, developing means for developing an electrostatic charge image using the contained toner for developing an electrostatic charge image, and cleaning means having a cleaning blade, wherein the toner for developing an electrostatic charge image has a solid lubricant containing only a fatty acid metal salt, or compared with the case of including coating means for coating a solid lubricant containing only a fatty acid metal salt on the electrophotographic photoreceptor, deterioration of transferability to a recording medium having large surface irregularities is suppressed.

Brief Description of the Drawings

[0011] [Figure 1] [[ID==16]]It is a schematic configuration diagram showing an image forming apparatus according to the present embodiment. [[ID=1Z]] [Figure 2] It is a schematic configuration diagram showing a process cartridge according to the present embodiment.

Mode for Carrying Out the Invention

[0012] Embodiments of the present disclosure will be described below. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments.

[0013] In the numerical ranges described step by step in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other step-by-step descriptions. Also, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0014] In the present disclosure, each component may contain a plurality of corresponding substances. When referring to the amount of each component in the composition, in the case where there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition.

[0015] <Image Forming Apparatus> The image forming apparatus according to the present embodiment includes an electrophotographic photoreceptor having a photosensitive layer, charging means for charging the surface of the electrophotographic photoreceptor, electrostatic charge image forming means for forming an electrostatic charge image on the charged surface of the electrophotographic photoreceptor, developing means for accommodating an electrostatic charge developer containing toner for developing the electrostatic charge image and developing the electrostatic charge image formed on the surface of the electrophotographic photoreceptor as a toner image, transfer means for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, and cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, and is an image forming apparatus that satisfies at least one of the following conditions (1) and condition (2). Condition (1): The toner for developing the electrostatic charge image has a solid lubricant containing a fatty acid metal salt and an antioxidant. Condition (2): Coating means for coating a solid lubricant containing a fatty acid metal salt and an antioxidant on the electrophotographic photoreceptor is provided.

[0016] In the image forming apparatus according to this embodiment, the electrophotographic photoreceptor is also simply referred to as the "photoreceptor," the electrostatic image developing toner is also simply referred to as the "toner," and the electrostatic image developing agent is also simply referred to as the "developer."

[0017] To ensure stable cleaning of the photoreceptor surface by a cleaning blade, a solid lubricant is sometimes supplied to the photoreceptor. Known methods for supplying a solid lubricant to the photoreceptor include, for example, using a fatty acid metal salt as toner, or coating the photoreceptor with a fatty acid metal salt. However, if the fatty acid portion of the fatty acid metal salt supplied to the photoreceptor is broken off by discharge or the like, the remaining fatty acid metal salt can reduce the transferability of images to recording media with large irregularities on the surface, such as embossed paper (hereinafter also referred to as transferability to embossed paper).

[0018] As mentioned above, the transferability to embossed paper is affected by the degradation of fatty acid metal salts. It is presumed that the degradation of fatty acid metal salts is caused by the generation of radicals due to discharge during transfer, which in turn cause the long-chain C / C bonds of the fatty acids to cleave and break due to oxygen in the atmosphere. In the image forming apparatus according to this embodiment, as described above, a solid lubricant containing an antioxidant together with a fatty acid metal salt is used. Since the antioxidant has functions such as deactivating radicals and suppressing the cleavage of CC bonds by oxygen, it is presumed that it can effectively suppress the deterioration of the fatty acid metal salt coexisting in the solid lubricant. Therefore, it is presumed that the image forming apparatus according to this embodiment can suppress the deterioration of transferability to recording media with large surface irregularities.

[0019] The configuration of the image forming apparatus according to this embodiment will be described in detail.

[0020] The image forming apparatus according to this embodiment comprises: an electrophotographic photoreceptor having a photosensitive layer; charging means for charging the surface of the electrophotographic photoreceptor; electrostatic image forming means for forming an electrostatic image on the charged surface of the electrophotographic photoreceptor; developing means containing an electrostatic image developer including an electrostatic image developing toner, and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the electrostatic image developer; transfer means for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium; and cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor. Furthermore, the electrostatic image developing toner has a solid lubricant containing a fatty acid metal salt and an antioxidant (condition (1)), and the device includes a coating means for applying the solid lubricant containing the fatty acid metal salt and antioxidant onto the electrophotographic photoreceptor (condition (2)).

[0021] In other words, the image forming apparatus according to this embodiment can supply a solid lubricant containing a fatty acid metal salt and an antioxidant onto an electrophotographic photoreceptor by at least one of the following: the electrostatic image developing toner contains a solid lubricant containing a fatty acid metal salt and an antioxidant, and the apparatus includes a coating means for applying the solid lubricant containing the fatty acid metal salt and the antioxidant onto the electrophotographic photoreceptor. In other words, if the electrostatic image developer contained in the developing means includes an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant, then such developing means also serves as a means for supplying a solid lubricant containing the fatty acid metal salt and the antioxidant onto the electrophotographic photoreceptor. When the electrostatic image developing toner contains a solid lubricant containing a fatty acid metal salt and an antioxidant, the developing means applies the electrostatic image developing toner to the surface of the electrophotographic photoreceptor, thereby supplying a solid lubricant containing the fatty acid metal salt and the antioxidant onto the electrophotographic photoreceptor.

[0022] The image forming apparatus according to this embodiment is applicable to well-known image forming apparatuses such as: a direct transfer apparatus that directly transfers a toner image formed on the surface of a photoreceptor to a recording medium; an intermediate transfer apparatus that first transfers a toner image formed on the surface of a photoreceptor to the surface of an intermediate transfer body, and secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium; and an apparatus equipped with a static elimination device that irradiates the surface of the photoreceptor with static elimination light to eliminate static charge after the transfer of the toner image and before charging. In the case of an intermediate transfer method apparatus, the transfer apparatus may include, for example, an intermediate transfer body on which a toner image is transferred; a primary transfer apparatus (an example of a primary transfer means) that first transfers the toner image formed on the surface of an electrophotographic photoreceptor to the surface of the intermediate transfer body; and a secondary transfer apparatus (an example of a secondary transfer means) that secondarily transfers the toner image transferred to the surface of the intermediate transfer body to the surface of a recording medium.

[0023] In addition, in the image forming apparatus according to this embodiment, for example, the part including the electrophotographic photoreceptor, developing means, and cleaning means may be a cartridge structure (process cartridge) that can be attached to and detached from the image forming apparatus.

[0024] The following is an example of an image forming apparatus according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will be omitted from the description.

[0025] The image forming apparatus according to this embodiment that satisfies the previously described condition (2) will be described below with reference to Figure 1. Figure 1 is a schematic diagram showing the image forming apparatus according to this embodiment. The image forming apparatus shown in Figure 1 is equipped with first to fourth electrophotographic image forming units 10Y, 10M, 10C, and 10K (image forming means) that output images of yellow (Y), magenta (M), cyan (C), and black (K) based on color-separated image data. These image forming units (hereinafter sometimes simply referred to as "units") 10Y, 10M, 10C, and 10K are arranged side by side at predetermined distances from each other in the horizontal direction. These units 10Y, 10M, 10C, and 10K may also be process cartridges that can be attached to and detached from the image forming apparatus.

[0026] In the drawings of each unit 10Y, 10M, 10C, and 10K, an intermediate transfer belt 20 is extended through each unit as an intermediate transfer body. The intermediate transfer belt 20 is wound around drive rolls 22 and support rolls 24 that are spaced apart from each other from left to right in the drawing and are in contact with the inner surface of the intermediate transfer belt 20, and is designed to travel in the direction from the first unit 10Y to the fourth unit 10K. The support rolls 24 are subjected to a force that moves away from the drive rolls 22 by a spring or the like (not shown), and tension is applied to the intermediate transfer belt 20 wound around both. An intermediate transfer body cleaning device 30 is provided on the image forming surface side of the intermediate transfer belt 20, facing the drive rolls 22. Furthermore, each of the developing devices (examples of developing means) 4Y, 4M, 4C, and 4K for each unit 10Y, 10M, 10C, and 10K is supplied with toner containing four colors of toner: yellow, magenta, cyan, and black, contained in toner cartridges 8Y, 8M, 8C, and 8K.

[0027] Since the first to fourth units 10Y, 10M, 10C, and 10K have equivalent configurations, the first unit 10Y, which forms the yellow image and is located on the upstream side in the direction of travel of the intermediate transfer belt, will be described as a representative example. The descriptions of the second to fourth units 10M, 10C, and 10K will be omitted by assigning reference numerals to parts equivalent to the first unit 10Y, with magenta (M), cyan (C), and black (K) instead of yellow (Y).

[0028] The first unit 10Y has a photoreceptor 1Y that acts as an image holder. Around the photoreceptor 1Y are, in order, a charging roll (an example of a charging means) 2Y that charges the surface of the photoreceptor 1Y to a predetermined potential, an exposure device (an example of a charge image forming means) 3 that exposes the charged surface with a laser beam 3Y based on a color-separated image signal to form a charge image, a developing device (an example of a developing means) 4Y that supplies charged toner to the charge image to develop the charge image, a primary transfer roll 5Y (an example of a primary transfer means) that transfers the developed toner image onto an intermediate transfer belt 20, a lubricant application device (an example of a lubricant application means) 6Y that applies lubricant to the surface of the photoreceptor 1Y, and a photoreceptor cleaning device (an example of a cleaning means) 7Y that has a cleaning blade 7Y-1 to remove toner remaining on the surface of the photoreceptor 1Y after primary transfer.

[0029] Furthermore, the primary transfer roll 5Y is positioned inside the intermediate transfer belt 20 and opposite the photoreceptor 1Y. In addition, each of the primary transfer rolls 5Y, 5M, 5C, and 5K is connected to a bias power supply (not shown) that applies a primary transfer bias. Each bias power supply varies the transfer bias applied to each primary transfer roll through control by a control unit (not shown).

[0030] Here, the lubricant application device 6Y and the photoreceptor cleaning device 7Y will be described in detail. The lubricant application device 6Y is not particularly limited as long as it is configured to apply a solid lubricant to the surface of the photoreceptor 1Y. An example of the lubricant application means 6Y is that it comprises a solid lubricant and a rotating brush that comes into contact with the solid lubricant and the surface (circumferential surface) of the photoreceptor 1Y to apply the solid lubricant to the photoreceptor 1Y. As the photoreceptor 1Y rotates, the rotating brush rotates, and the solid lubricant is applied to the surface of the photoreceptor 1Y via the rotating brush.

[0031] The amount of solid lubricant supplied by the lubricant application device 6Y is preferably 5 mg to 20 mg per 1000 revolutions of the photoreceptor 1Y, and more preferably 8 mg to 15 mg.

[0032] The photoreceptor cleaning device 7Y is equipped with a cleaning blade 7Y-1 that is pressed against the surface (circumferential surface) of the photoreceptor 1Y and scrapes off (removes) residues, including residual toner after transfer, from the surface of the photoreceptor 1Y. The cleaning blade 7Y-1 is a plate-shaped (blade-shaped) component, and is made of, for example, an elastic material. Examples of such elastic materials include thermosetting polyurethane rubber, silicone rubber, fluororubber, and ethylene-propylene-diene rubber. The cleaning blade 7Y-1 is positioned such that, for example, the end on the proximal side of the photoreceptor 1Y is facing in the opposite direction to the rotation of the photoreceptor 1Y. The contact pressure of the cleaning blade 7Y-1 (the pressure applied radially to the photoreceptor 1Y) is set to, for example, 9.8 mN / mm or more and 49 mN / mm or less (1.0 gf / mm or more and 5.0 gf / mm or less).

[0033] The following describes the process of forming the yellow image in the first unit 10Y. First, prior to operation, the surface of the photoreceptor 1Y is charged to a potential of -600V to -800V by the charging roll 2Y. The photoreceptor 1Y is conductive (for example, volume resistivity at 20°C: 1 × 10⁻⁶). -6A photosensitive layer is formed on a substrate (less than Ωcm). This photosensitive layer normally has high resistance (resistance of a general resin), but when irradiated with a laser beam 3Y, the resistivity of the irradiated area changes. Therefore, a laser beam 3Y is output to the surface of a charged photoreceptor 1Y via an exposure device 3, according to image data for yellow sent from a control unit (not shown). The laser beam 3Y irradiates the photosensitive layer on the surface of the photoreceptor 1Y, thereby forming an electrostatic image of the yellow image pattern on the surface of the photoreceptor 1Y.

[0034] A static charge image is an image formed on the surface of a photoreceptor 1Y due to charging. It is a so-called negative latent image formed when the resistivity of the irradiated portion of the photoreceptor layer decreases due to the laser beam 3Y, causing the charged material on the surface of the photoreceptor 1Y to flow, while the charge remains in the portion not irradiated by the laser beam 3Y. The electrostatic charge image formed on the photoreceptor 1Y is rotated to a predetermined development position as the photoreceptor 1Y moves. At this development position, the electrostatic charge image on the photoreceptor 1Y is made visible as a toner image (developed image) by the developing device 4Y.

[0035] The developing device 4Y contains, for example, an electrostatic image developer including at least yellow toner and a carrier. The yellow toner is triboelectrically charged by being agitated inside the developing device 4Y and is held on the developer roll (an example of a developer holder) with a charge of the same polarity (negative polarity) as the static charge on the photoreceptor 1Y. As the surface of the photoreceptor 1Y passes through the developing device 4Y, the yellow toner electrostatically adheres to the discharged latent image on the surface of the photoreceptor 1Y, and the latent image is developed by the yellow toner. The photoreceptor 1Y, on which the yellow toner image has been formed, continues to move at a predetermined speed, and the toner image developed on the photoreceptor 1Y is transported to a predetermined primary transfer position.

[0036] When the yellow toner image on the photoreceptor 1Y is transported to the primary transfer position, a primary transfer bias is applied to the primary transfer roll 5Y, and an electrostatic force acts on the toner image from the photoreceptor 1Y toward the primary transfer roll 5Y, transferring the toner image on the photoreceptor 1Y onto the intermediate transfer belt 20. The transfer bias applied at this time has a polarity opposite to the toner's polarity (-) (+), and in the first unit 10Y, for example, it is controlled to +10 μA by the control unit (not shown).

[0037] After transferring the toner image to the surface of the intermediate transfer belt 20, the photoreceptor 1Y continues to rotate. As the photoreceptor 1Y rotates, the rotating brush of the lubricant application device 6Y rotates, and lubricant is applied (supplied) to the surface of the photoreceptor 1Y via the rotating brush.

[0038] The photoreceptor 1Y, coated with lubricant, continues to rotate, and as the rotating photoreceptor 1Y comes into contact with the cleaning blade 7Y-1 of the photoreceptor cleaning device 7Y, residues, including residual toner after transfer, are scraped off and removed from the surface of the photoreceptor 1Y. The toner removed from the photoreceptor 1Y is then collected by a toner recovery mechanism (not shown).

[0039] Furthermore, the primary transfer bias applied to the primary transfer rolls 5M, 5C, and 5K of the second unit from 10M onward is also controlled in accordance with the first unit. Thus, the intermediate transfer belt 20, on which the yellow toner image has been transferred in the first unit 10Y, is sequentially transported through the second to fourth units 10M, 10C, and 10K, and the toner images of each color are superimposed and transferred in multiple layers.

[0040] The intermediate transfer belt 20, on which four-color toner images have been multiple-transferred through the first to fourth units, proceeds to a secondary transfer section composed of the intermediate transfer belt 20, a support roll 24 in contact with the inner surface of the intermediate transfer belt, and a secondary transfer roll (an example of a secondary transfer means) 26 positioned on the image-holding surface side of the intermediate transfer belt 20. Meanwhile, recording paper (an example of a recording medium) P is fed via a supply mechanism into the gap between the secondary transfer roll 26 and the intermediate transfer belt 20 at a predetermined timing, and a secondary transfer bias is applied to the support roll 24. The transfer bias applied at this time has the same polarity (-) as the toner's polarity (-), and an electrostatic force from the intermediate transfer belt 20 toward the recording paper P acts on the toner image, transferring the toner image on the intermediate transfer belt 20 onto the recording paper P. The secondary transfer bias at this time is determined according to the resistance detected by a resistance detection means (not shown) that detects the resistance of the secondary transfer section, and is voltage-controlled.

[0041] After this, the recording paper P is fed to the contact area (nip area) of a pair of fixing rolls in a fixing device (an example of fixing means) 28, where the toner image is fixed onto the recording paper P, and a fixed image is formed.

[0042] Examples of recording paper P used to transfer toner images include plain paper used in electrophotographic copiers and printers, as well as embossed paper. Other recording media besides recording paper P include OHP sheets.

[0043] Once the color image has been fixed onto the recording paper P, it is discharged towards the output section, and the series of color image formation operations is completed.

[0044] In the image recording apparatus shown in Figure 1, in order to satisfy the previously described condition (2), a solid lubricant containing a fatty acid metal salt and an antioxidant should be applied to at least some of the lubricant application devices 6Y, 6M, 6C, and 6K. From the viewpoint of further suppressing deterioration of transferability to embossed paper, it is preferable to apply a solid lubricant containing a fatty acid metal salt and an antioxidant to all of the lubricant application devices 6Y, 6M, 6C, and 6K, and to apply the solid lubricant containing a fatty acid metal salt and an antioxidant to all surfaces of the photoreceptors 1Y, 1M, 1C, and 1K. Furthermore, each of the electrostatic image developers contained in the developing units 4Y, 4M, 4C, and 4K does not need to contain an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant, but it may contain such an electrostatic image developing toner. If some or all of the electrostatic image developers contained in the developing units 4Y, 4M, 4C, and 4K contain an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant, then condition (1) will be satisfied along with the previously described condition (2).

[0045] The image forming apparatus shown in Figure 1 has a configuration in which a lubricant application device and a cleaning device are provided separately, but the embodiment is not limited to this configuration. For example, the cleaning device may be configured to incorporate a lubricant application device inside the device. In this configuration, it is preferable that the lubricant application device be located upstream of the cleaning blade in the direction of rotation of the electrophotographic photoreceptor, in order to improve the dispersibility of the solid lubricant on the surface of the electrophotographic photoreceptor.

[0046] The image forming apparatus shown in Figure 1 is an image forming apparatus that satisfies the previously described condition (2), and therefore has a configuration that includes a lubricant application device (an example of a lubricant application means). However, in the case of an image forming apparatus that satisfies the previously described condition (1), it is not necessary to include a lubricant application device (an example of a lubricant application means). An example of an image forming apparatus that satisfies the previously described condition (1) is an image forming apparatus that has a similar configuration to the image forming apparatus shown in Figure 1, except that the lubricant application device (an example of a lubricant application means) is removed. In this case, some or all of the electrostatic image developer contained in the developing devices 4Y, 4M, 4C, and 4K includes an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant. In other words, some or all of the developing devices 4Y, 4M, 4C, and 4K that contain the electrostatic image developer including an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant also serve as means for supplying the solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor.

[0047] The image forming apparatus shown in Figure 1 is an image forming apparatus with removable toner cartridges 8Y, 8M, 8C, and 8K. The developing units 4Y, 4M, 4C, and 4K are connected to toner cartridges corresponding to each developing unit (color) by toner supply pipes (not shown). When the toner contained in a toner cartridge becomes low, the toner cartridge is replaced.

[0048] <Processor Cartridges / Toner Cartridges> Next, the process cartridge according to this embodiment will be described. The process cartridge according to this embodiment is a process cartridge that can be attached to and detached from an image forming apparatus, and contains an electrostatic image developer including an electrostatic image developing toner, and comprises a developing means for developing an electrostatic image formed on the surface of an electrophotographic photoreceptor as a toner image using the electrostatic image developer, and a cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, and satisfies at least one of the following conditions (1) and (2). Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor.

[0049] The process cartridge according to this embodiment is not limited to the above configuration, and may also include, as necessary, at least one selected from other means such as charging means, electrostatic image forming means, and transfer means.

[0050] The following shows an example of a process cartridge according to this embodiment, but it is not limited to this example. The main parts shown in the figure will be described, and other parts will not be explained.

[0051] The process cartridge according to this embodiment that satisfies the previously described condition (2) will be explained below with reference to Figure 2. Figure 2 is a schematic diagram showing the process cartridge according to this embodiment. The process cartridge 200 shown in Figure 2 is constructed by integrally holding a photoreceptor 107, a charging roll 108 (an example of a charging means), a developing device 111 (an example of a developing means), a photoreceptor cleaning device 113 (an example of a cleaning means), and a lubricant application device (an example of a lubricant application means) 114, all of which are provided around the photoreceptor 107, within a housing 117 equipped with a mounting rail 116 and an opening 118 for exposure, and thus forming a cartridge.

[0052] Here, the lubricant application device (an example of a lubricant application means) 113 is not particularly limited as long as it is configured to apply a solid lubricant containing a fatty acid metal salt and an antioxidant to the surface of the photoreceptor 107. As shown in Figure 2, the lubricant application device 113 comprises a solid lubricant 113S containing a fatty acid metal salt and an antioxidant, and a rotating brush 113B that contacts the solid lubricant 113S and the surface (circumferential surface) of the photoreceptor 107 to apply the lubricant to the photoreceptor 107. Furthermore, the photoreceptor cleaning device 114 is equipped with a cleaning blade 114-1 that contacts the surface (circumferential surface) of the photoreceptor 107 to rub off (scrape off) any residual toner.

[0053] Furthermore, the electrostatic image developer contained in the developing device 111 does not necessarily have to contain an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant, but it may contain such an electrostatic image developing toner. If the electrostatic image developer contained in the developing device 111 contains an electrostatic image developing toner having a solid lubricant containing a fatty acid metal salt and an antioxidant, then condition (1) will be satisfied along with the previously described condition (2).

[0054] In Figure 2, 109 is an exposure apparatus (an example of electrostatic image formation means), 112 is a transfer apparatus (an example of a transfer means), 115 is a fixing apparatus (an example of a fixing means), and 300 is recording paper (an example of a recording medium).

[0055] [Solid lubricant] The solid lubricant in this embodiment will now be described. In this embodiment, the solid lubricant comprises a fatty acid metal salt and an antioxidant.

[0056] (Fatty acid metal salts) The fatty acid in a fatty acid metal salt may be either a saturated or unsaturated fatty acid. Examples of fatty acids in a fatty acid metal salt include fatty acids with 10 to 25 carbon atoms (preferably 12 to 22 carbon atoms). The carbon atoms of the fatty acid include the carbon atoms of the carboxyl group. Divalent metals are preferred as the metals in fatty acid metal salts. Examples of metals in fatty acid metal salts include magnesium, calcium, aluminum, barium, and zinc, with zinc being the most preferred among these.

[0057] Examples of fatty acid metal salts include metal salts of stearic acid, palmitic acid, lauric acid, oleic acid, linoleic acid, and ricinoleic acid. Among these, it is preferable that the fatty acid metal salt includes at least one selected from metal salts of stearic acid and lauric acid, more preferably at least one selected from zinc stearate and zinc laurate, and even more preferably zinc stearate.

[0058] The fatty acid metal salts contained in the solid lubricant may be used individually or in combination of two or more types.

[0059] (Antioxidant) The antioxidant included in the solid lubricant is not particularly limited, as long as it has antioxidant properties and can constitute the solid lubricant together with the fatty acid metal salt. However, from the viewpoint of forming a solid lubricant, it is preferable that the antioxidant is in powder form (i.e., solid) at 25°C. From the viewpoint of preventing degradation of fatty acid metal salts, applicability to solid lubricants, and availability, the antioxidant preferably contains one or more selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants, and more preferably contains one or more selected from the group consisting of phenolic antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants.

[0060] Examples of phenolic antioxidants include 2,6-di-t-butyl-p-cresol (BHT), 2,6-di-t-butylphenol, 2,4-di-methyl-6-t-butylphenol, butylhydroxyphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(3-methyl-6-t-butylphenol), bisphenol A, DL-α-tocopherol, styrenated phenol, styrenated cresol, 3,5-di-t-butylhydroxybenzaldehyde, and 2,6-di-t-butyl-4 -Hydroxymethylphenol, 2,6-di-s-butylphenol, 2,4-di-t-butylphenol, 3,5-di-t-butylphenol, on-butoxyphenol, ot-butylphenol, mt-butylphenol, pt-butylphenol, o-isobutoxyphenol, on-propoxyphenol, o-cresol, 4,6-di-t-butyl-3-methylphenol, 2,6-dimethylphenol, 2,3,5,6-tetramethylphenol, 3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionyl Stearyl ester, 2,4,6-tri-t-butylphenol, 2,4,6-trimethylphenol, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)mesitylene, 1,6-hexanediol-bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thiobis(4-methyl-6-t-butylphenol), 3,5-di-t-butyl-4-hydroxyphenyl Cy-benzyl phosphate, on-propoxyphenol, o-cresol, 4,6-di-t-butyl-3-methylphenol, 2,6-dimethylphenol, 2,3,5,6-tetramethylphenol, 3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionic acid stearyl ester, 2,4,6-tri-t-butylphenol, 2,4,6-trimethylphenol, 2,4,6-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)mesitylene, 1,6-hexanediol-bis[3-(3,[5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], 2,2-thiobis(4-methyl-6-t-butylphenol), 3,5-di-t-butyl-4-hydroxybenzylphosphate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxylbenzylbenzene), n-octadecyl-3-(3',5 Examples include (-di-t-butyl-4-hydroxyphenyl)propionate, 2-t-butyl-6(3'-t-butyl-5'-methyl-2-hydroxybenzyl)-4-methylphenyl acrylate, 4,4'-butylidene-bis(3-methyl-6-t-butylphenol), pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], hydroquinone, 2,5-di-t-butylhydroquinone, tetramethylhydroquinone, etc. In particular, as phenolic antioxidants, 2,6-di-t-butyl-p-cresol (BHT) and pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] are preferred from the viewpoint of suppressing deterioration of transferability to embossed paper.

[0061] Examples of phosphorus-based antioxidants include trimethyl phosphite, tolethyl phosphite, tri-n-butyl phosphite, trioctyl phosphite, tridecyl phosphite, tristearyl phosphite, trioleyl phosphite, tristridecyl phosphite, tricetyl phosphite, dilauryl hydrodiene phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, tetraphenyldipropylene glycol diphosphite, and 4,4'-butylidene-bis[3-methyl- Examples of phosphite ester compounds include 6-t-(butyl)phenyl-di-tridecyl]phosphite, distearyl pentaerythritol diphosphite, ditridecyl pentaerythritol diphosphite, bisnonylphenyl pentaerythritol diphosphite, diphenyloctyl phosphite, tetra(tridecyl)-4,4'-isopropylidene diphenyl diphosphite, tris(2,4-di-t-butylphenyl)phosphite, and di(2,4-di-t-butylphenyl)pentaerythritol diphosphite. Among phosphorus-based antioxidants, tris(2,4-di-t-butylphenyl) phosphite is preferred from the viewpoint of suppressing deterioration of transferability to embossed paper.

[0062] Examples of sulfur-based antioxidants include 3,3'-thiodipropionate-di-n-dodecyl, 3,3'-thiodipropionate-dimyristyl, 3,3'-thiodipropionate-di-n-octadecyl, 2-mercaptobenzimidazole, pentaelsultol-tetrakis-(β-lauryl,urylthiopropionate), ditridecyl-3,3'-thiodipropionate, dimethyl 3,3'-thiodipropionate, and thioglycolic acid. Examples include octadecyl, phenothiazine, β,β'-thiodipropionic acid, n-butyl thioglycolate, ethyl thioglycolate, 2-ethylhexyl thioglycolate, isooctyl thioglycolate, n-octyl thioglycolate, di-t-dodecyl disulfide, n-butyl sulfide, di-n-amyl disulfide, n-dodecyl sulfide, n-octadecyl sulfide, and p-thiocresol. Among them, sulfur As an antioxidant, 3,3'-thiodipropionic acid-di-n-dodecyl is preferred from the viewpoint of suppressing deterioration of transferability to embossed paper.

[0063] Examples of hindered amine antioxidants include bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, 1-{2-[3-(3,5-di-t-butyl-4-hydrophenyl)propionyloxy]ethyl}-4-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy-2,2,6,6-tetramethylpyridine, 8-ben Examples of compounds having a hindered amine structure include zyl-7,7,9,9-tetramethyl-3-octyl-1,3,8-triazaspiro[4,5]undecane-2,4-dione, benzoyloxy-2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-piperidinol, and tetrakis(2,2,6,6-teto-tetramethyl-4-piperidyl / decyl)-1,2,3,4-butanetetracarboxylate. Furthermore, commercially available hindered amine antioxidants may be used. An example of a commercially available hindered amine antioxidant is the ADEKA LA series manufactured by ADEKA Corporation. The hindered amine antioxidant may be a high molecular weight compound with a molecular weight of 1500 or more. Specifically, examples include ADEKA LA-63P and ADEKA LA-68 from the ADEKA LA series manufactured by ADEKA Corporation. Among these, as hindered amine antioxidants, AdekaStab LA-63P, AdekaStab LA-68, etc. are preferred from the viewpoint of suppressing deterioration of transferability to embossed paper.

[0064] From the viewpoint of further suppressing deterioration of transferability to embossed paper, the antioxidant contained in the solid lubricant preferably includes a phenolic antioxidant and one or more antioxidants selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants. In particular, from the viewpoint of further suppressing deterioration of transferability to embossed paper, it is preferable that the antioxidant contained in the solid lubricant includes a phenolic antioxidant and a sulfuric antioxidant. In other words, the solid lubricant preferably contains, as an antioxidant, a phenolic antioxidant and one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants, and more preferably contains a phenolic antioxidant and a sulfur-based antioxidant. By combining multiple types of antioxidants, the degradation of fatty acid metal salts can be more effectively suppressed. In this embodiment, as described above, a phenolic antioxidant is used as the first type of antioxidant, and by using one or more antioxidants selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants in combination with it, the functions of deactivating radicals and suppressing the cleavage of CC bonds by oxygen are effectively expressed, and it is presumed that the degradation of fatty acid metal salts coexisting in the solid lubricant can be effectively suppressed.

[0065] Antioxidants contained in solid lubricants of From the viewpoint of suppressing deterioration of transferability to embossed paper, the content is preferably 1% by mass or more and 50% by mass or less, preferably 5% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 40% by mass or less, based on the total mass of the solid lubricant.

[0066] Furthermore, if the antioxidant includes a phenolic antioxidant, the content of the phenolic antioxidant is preferably 1% to 100% by mass, more preferably 10% to 100% by mass, and even more preferably 30% to 100% by mass, relative to the total mass of the antioxidant, from the viewpoint of further suppressing deterioration of transferability to embossed paper. In other words, when the antioxidant includes a phenolic antioxidant, it is preferable that the phenolic antioxidant be present in an amount of 1% by mass or more, more preferably 10% by mass or more, and even more preferably 30% by mass or more, relative to the total mass of the antioxidant. The entire antioxidant may also be a phenolic antioxidant.

[0067] Furthermore, if the antioxidant includes a phenolic antioxidant and one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants, the content of the phenolic antioxidant is preferably 1% by mass or more, more preferably 10% by mass or more, and even more preferably 30% by mass or more, based on the total mass of the antioxidant. In this case, the content of the phenolic antioxidant is preferably 90% by mass or less, and more preferably 70% by mass or less, relative to the total mass of the antioxidant.

[0068] The shape, size, etc., of the solid lubricant should be appropriately determined depending on whether it is applied to toner or to a lubricant application means (for example, a lubricant application device 64). For example, when applying a solid lubricant to toner, it is preferable that the solid lubricant be an external additive. As an external additive, the solid lubricant can be prepared by mixing fatty acid metal salt particles and antioxidant particles with toner particles using a known mixer such as a V-type blender, Henschel mixer, or Reidige mixer. Thus, a solid lubricant as an external additive refers to a mixture of fatty acid metal salt particles and antioxidant particles. Furthermore, when applying a solid lubricant to a lubricant application means (for example, a lubricant application device 64), a molded body of the solid lubricant (for example, a rod-shaped molded body) can be produced by compression molding a solid lubricant containing fatty acid metal salt particles and antioxidant particles, followed by heat treatment. The molded body of the solid lubricant is then fixed to a holding member and installed in the lubricant application means.

[0069] -Fatty acid metal salt particles- The fatty acid metal salt particles are preferably 0.3 μm to 8 μm in size, and more preferably 0.5 μm to 5.0 μm.

[0070] The volume-average particle diameter of fatty acid metal salt particles is measured by the following method. First, the toner to be measured is observed using a scanning electron microscope (SEM). Then, the equivalent circle diameter of each of the 100 lubricant particles to be measured is determined by image analysis, and the volume-average particle diameter is defined as the equivalent circle diameter of the 50th particle (50th particle) from the smallest diameter side in the volume-based distribution. The image analysis to determine the equivalent circle diameter of the 100 lubricant particles to be measured is performed using an analysis device (ERA-8900: manufactured by Elionix Co., Ltd.) to capture a two-dimensional image at a magnification of 10,000x, and the projected area is determined using the image analysis software WinROOF (Mitani Corporation) under the condition of 0.010000 μm / pixel, and the equivalent circle diameter is calculated using the formula: equivalent circle diameter = 2√(projected area / π).

[0071] The content of fatty acid metal salt particles (external addition amount) is preferably 0.02 parts by mass or more and 5 parts by mass or less, more preferably 0.05 parts by mass or more and 3.0 parts by mass or less, and even more preferably 0.08 parts by mass or more and 1.0 part by mass or less, per 100 parts by mass of toner particles.

[0072] [Electrostatic Image Developer] The electrostatic image developer according to this embodiment includes at least toner. The electrostatic image developer according to this embodiment may be a one-component developer containing only toner, or a two-component developer containing toner and a carrier.

[0073] 〔toner〕 The toner according to this embodiment includes toner particles. In addition to the toner particles, the toner according to this embodiment further comprises, as necessary, fatty acid metal salt particles, antioxidant particles, other external additives (hereinafter also referred to as other external additives), etc.

[0074] <Toner particles> Toner particles are composed of, for example, a binder resin, and optionally, a colorant, a release agent, and other additives.

[0075] -Binding resin- Examples of binder resins include vinyl resins consisting of monomers such as styrenes (e.g., styrene, parachlorostyrene, α-methylstyrene, etc.), (meth)acrylic acid esters (e.g., methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, etc.), ethylenically unsaturated nitriles (e.g., acrylonitrile, methacrylonitrile, etc.), vinyl ethers (e.g., vinyl methyl ether, vinyl isobutyl ether, etc.), vinyl ketones (vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), or copolymers of two or more of these monomers. Examples of binder resins include non-vinyl resins such as epoxy resins, polyester resins, polyurethane resins, polyamide resins, cellulose resins, polyether resins, and modified rosin; mixtures of these with the aforementioned vinyl resins; and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binding resins may be used individually or in combination of two or more types.

[0076] (1) Styrene acrylic resin Styrene-acrylic resin is preferred as the binder resin. Styrene-acrylic resin is a copolymer obtained by copolymerizing at least a styrene monomer (a monomer having a styrene skeleton) and a (meth)acrylic monomer (a monomer having a (meth)acryloyl group, preferably a monomer having a (meth)acryloyloxy group). Styrene-acrylic resin includes, for example, a copolymer of styrene monomers and the aforementioned (meth)acrylic acid ester monomers. The acrylic resin portion in styrene-acrylic resin is either an acrylic monomer or a methacrylic monomer, or a substructure obtained by polymerizing them. Furthermore, "(meth)acrylic" is an expression that includes both "acrylic" and "methacrylic".

[0077] Examples of styrene monomers include styrene, alkyl-substituted styrenes (e.g., α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, etc.), halogen-substituted styrenes (e.g., 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, etc.), vinylnaphthalene, etc. Styrene monomers may be used individually or in combination of two or more. Among these, styrene is preferred as the styrene monomer due to its reactivity, ease of reaction control, and availability.

[0078] Examples of (meth)acrylic monomers include, specifically, (meth)acrylic acid and (meth)acrylic acid esters. Examples of (meth)acrylic acid esters include alkyl (meth)acrylates (e.g., methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, n-lauryl (meth)acrylate, n-tetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, n-octadecyl (meth)acrylate, isopropyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isopentyl (meth)acrylate, amyl (meth)acrylate, (meth) Examples include neopentyl acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, etc., aryl (meth)acrylates (e.g., phenyl (meth)acrylate, biphenyl (meth)acrylate, diphenylethyl (meth)acrylate, t-butylphenyl (meth)acrylate, terphenyl (meth)acrylate, etc.), dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, β-carboxyethyl (meth)acrylate, and (meth)acrylamide. The (meth)acrylic acid monomers may be used individually or in combination of two or more. Of the (meth)acrylic monomers, among these (meth)acrylic esters, (meth)acrylic acid esters having an alkyl group with 2 to 14 carbon atoms (preferably 2 to 10 carbon atoms, more preferably 3 to 8 carbon atoms) are preferred from the viewpoint of improving toner fixation. Among these, n-butyl (meth)acrylate is preferred, and n-butyl acrylate is particularly preferred.

[0079] The copolymerization ratio (by mass, styrene monomer / (meth)acrylic monomer) of the styrene monomer and the (meth)acrylic monomer is not particularly limited, but is preferably 90 / 10 to 60 / 40.

[0080] Styrene-acrylic resins preferably have a crosslinked structure. Styrene-acrylic resins having a crosslinked structure are preferably obtained by copolymerizing at least a styrene monomer, a (meth)acrylic acid monomer, and a crosslinkable monomer.

[0081] Examples of crosslinkable monomers include crosslinking agents with two or more functionalities. Examples of bifunctional crosslinking agents include divinylbenzene, divinylnaphthalene, di(meth)acrylate compounds (e.g., diethylene glycol di(meth)acrylate, methylenebis(meth)acrylamide, decanediol diacrylate, glycidyl(meth)acrylate, etc.), polyester-type di(meth)acrylate, and 2-([1'-methylpropyleneamino]carboxyamino)ethyl methacrylate. Examples of crosslinking agents with three or more functions include tri(meth)acrylate compounds (e.g., pentaerythritol tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, etc.), tetra(meth)acrylate compounds (e.g., pentaerythritol tetra(meth)acrylate, oligoester(meth)acrylate, etc.), 2,2-bis(4-methacryloxy, polyethoxyphenyl)propane, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl chloridedate, etc. In particular, as crosslinkable monomers, from the viewpoint of improving the fixation of toner, (meth)acrylate compounds with two or more functions are preferred, bifunctional (meth)acrylate compounds are more preferred, bifunctional (meth)acrylate compounds having alkylene groups with 6 to 20 carbon atoms are even more preferred, and bifunctional (meth)acrylate compounds having linear alkylene groups with 6 to 20 carbon atoms are especially preferred.

[0082] The copolymerization ratio of the crosslinkable monomer to the total monomer (by mass, crosslinkable monomer / total monomer) is not particularly limited, but is preferably 2 / 1,000 to 20 / 1,000.

[0083] The glass transition temperature (Tg) of styrene-acrylic resin is preferably 40°C to 75°C, and more preferably 50°C to 65°C, from the viewpoint of improving toner fixation. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0084] From the viewpoint of toner storage stability, the weight-average molecular weight of the styrene-acrylic resin is preferably 5,000 to 200,000, more preferably 10,000 to 100,000, and particularly preferably 20,000 to 80,000.

[0085] There are no particular restrictions on the method for producing styrene-acrylic resin, and various polymerization methods (e.g., solution polymerization, precipitation polymerization, suspension polymerization, bulk polymerization, emulsion polymerization, etc.) can be applied. Furthermore, known polymerization reactions (e.g., batch, semi-continuous, continuous, etc.) can be used.

[0086] (2) Polyester resin Polyester resin is preferred as the binder resin. Examples of polyester resins include known amorphous polyester resins. In addition to amorphous polyester resins, crystalline polyester resins may also be used in combination. However, the crystalline polyester resin should be used in an amount of 2% to 40% by mass (preferably 2% to 20% by mass) relative to the total binding resin.

[0087] Furthermore, the "crystalline nature" of a resin refers to the presence of a clear endothermic peak rather than a stepwise change in endothermic quantity in differential scanning calorimetry (DSC). Specifically, it means that the full width at half maximum of the endothermic peak measured at a heating rate of 10°C / min is within 10°C. On the other hand, "amorphous" resins refer to those with a full width at half maximum exceeding 10°C, exhibiting a stepwise change in endothermic capacity, or lacking a clear endothermic peak.

[0088] Amorphous polyester resin Examples of amorphous polyester resins include condensation polymers of polycarboxylic acids and polyhydric alcohols. The amorphous polyester resin may be a commercially available product or a synthesized one.

[0089] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacic acid, etc.), alicyclic dicarboxylic acids (e.g., cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., with 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a cross-linked or branched structure. Examples of trivalent or higher carboxylic acids include trimellitic acid, pyromellitic acid, their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used individually or in combination of two or more.

[0090] Examples of polyhydric alcohols include aliphatic diols (e.g., ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, neopentyl glycol, etc.), alicyclic diols (e.g., cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, etc.), and aromatic diols (e.g., ethylene oxide adducts of bisphenol A, propylene oxide adducts of bisphenol A, etc.). Among these, aromatic diols and alicyclic diols are preferred as polyhydric alcohols, and aromatic diols are more preferred. As for the polyhydric alcohol, a trihydric or higher polyhydric alcohol with a cross-linked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0091] The glass transition temperature (Tg) of amorphous polyester resin is preferably 50°C to 80°C, and more preferably 50°C to 65°C. The glass transition temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, it is determined by the "extracorporeal glass transition onset temperature" described in the method for determining the glass transition temperature in JIS K 7121-1987 "Method for Measuring the Transition Temperature of Plastics".

[0092] The weight-average molecular weight (Mw) of the amorphous polyester resin is preferably 5,000 to 1,000,000, and more preferably 7,000 to 500,000. The number-average molecular weight (Mn) of the amorphous polyester resin is preferably between 2,000 and 100,000. The molecular weight distribution (Mw / Mn) of the amorphous polyester resin is preferably 1.5 to 100, and more preferably 2 to 60. The weight-average molecular weight and number-average molecular weight are measured by gel permeation chromatography (GPC). GPC molecular weight measurement is performed using a Tosoh GPC-HLC-8120GPC analyzer, a Tosoh TSKgel SuperHM-M (15cm) column, and THF solvent. The weight-average molecular weight and number-average molecular weight are calculated from these measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0093] Amorphous polyester resins can be obtained by well-known manufacturing methods. Specifically, for example, they can be obtained by a method in which the polymerization temperature is set to 180°C or higher and 230°C or lower, and the reaction system is subjected to reduced pressure as needed, while removing water and alcohol generated during condensation. If the monomers of the raw materials do not dissolve or become miscible at the reaction temperature, a high-boiling point solvent may be added as a solubilizer to dissolve them. In this case, the polycondensation reaction should be carried out while distilling off the solubilizer. If there are monomers with poor miscibility, it is advisable to condense the poorly miscible monomers with the acid or alcohol to be polycondensed with them beforehand, and then polycondense them together with the main component.

[0094] • Crystalline polyester resin Crystalline polyester resins include, for example, polycondensates of polycarboxylic acids and polyhydric alcohols. Commercially available crystalline polyester resins may be used, or synthesized resins may be used. Here, in order to easily form a crystalline structure, polycondensates using polymerizable monomers having linear aliphatic structures are preferred over polymerizable monomers having aromatic structures.

[0095] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (e.g., oxalic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonanedicarboxylic acid, 1,10-decanedicarboxylic acid, 1,12-dodecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, etc.), aromatic dicarboxylic acids (e.g., phthalic acid, isophthalic acid, terephthalic acid, dibasic acids such as naphthalene-2,6-dicarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). Polycarboxylic acids may be used in combination with dicarboxylic acids, or with trivalent or higher carboxylic acids that have a crosslinked or branched structure. Examples of trivalent carboxylic acids include aromatic carboxylic acids (e.g., 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-naphthalentricarboxylic acid, etc.), their anhydrides, or their lower alkyl esters (e.g., having 1 to 5 carbon atoms). In addition to these dicarboxylic acids, polycarboxylic acids with sulfonic acid groups and dicarboxylic acids with ethylenic double bonds may also be used in combination. Polycarboxylic acids may be used individually or in combination of two or more.

[0096] Examples of polyhydric alcohols include aliphatic diols (for example, linear aliphatic diols with 7 to 20 carbon atoms in the main chain). Examples of aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, and 1,14-eicosandecanediol. Among these, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol are preferred as aliphatic diols. Polyhydric alcohols may be used in combination with diols, including trihydric or higher alcohols that have a cross-linked or branched structure. Examples of trihydric or higher alcohols include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Polyhydric alcohols may be used individually or in combination of two or more types.

[0097] Here, the polyhydric alcohol is preferably composed of 80 mol% or more of aliphatic diols, and more preferably 90 mol% or more.

[0098] The melting temperature of the crystalline polyester resin is preferably 50°C to 100°C, more preferably 55°C to 90°C, and even more preferably 60°C to 85°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K7121-1987 "Method for determining the transition temperature of plastics".

[0099] The weight-average molecular weight (Mw) of the crystalline polyester resin is preferably between 6,000 and 35,000.

[0100] Crystalline polyester resins can be obtained, for example, by well-known manufacturing methods, similar to amorphous polyesters.

[0101] The binder resin content is preferably 40% to 95% by mass, more preferably 50% to 90% by mass, and even more preferably 60% to 85% by mass, relative to the total toner particles.

[0102] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa yellow, benzidine yellow, surene yellow, quinoline yellow, pigment yellow, permanent orange GTR, pyrazolone orange, balkan orange, Watch Young red, permanent red, brilliant carmine 3B, brilliant carmine 6B, DuPont oil red, pyrazolone red, risole red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine. Examples include various pigments such as phosphorus blue, chalcioyl blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate, as well as various dyes such as acridine, xanthene, azo, benzoquinone, azine, anthraquinone, thioindico, dioxazine, thiazine, azomethine, indico, phthalocyanine, aniline black, polymethine, triphenylmethane, diphenylmethane, and thiazole. Colorants may be used individually or in combination of two or more types.

[0103] The coloring agent may be a surface-treated coloring agent as needed, and may be used in combination with a dispersant. Furthermore, multiple types of coloring agents may be used in combination.

[0104] The colorant content is preferably 1% to 30% by mass, and more preferably 3% to 15% by mass, relative to the total toner particles.

[0105] -Release agent- Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these.

[0106] -Release agent- Examples of release agents include hydrocarbon waxes; natural waxes such as carnauba wax, rice wax, and candelilla wax; synthetic or mineral / petroleum-based waxes such as montan wax; and ester waxes such as fatty acid esters and montanic acid esters. However, the release agents are not limited to these.

[0107] The melting temperature of the release agent is preferably 50°C to 110°C, and more preferably 60°C to 100°C. The melting temperature is determined from the DSC curve obtained by differential scanning calorimetry (DSC) using the "melting peak temperature" described in JIS K 7121-1987 "Method for determining the transition temperature of plastics".

[0108] The release agent content is preferably 1% to 20% by mass, and more preferably 5% to 15% by mass, relative to the total toner particles.

[0109] -Other additives- Other additives include well-known additives such as magnetic materials, charge control agents, and inorganic powders. These additives are included in the toner particles as internal additives.

[0110] -Characteristics of toner particles, etc.- The toner particles may be single-layer toner particles, or they may be toner particles with a so-called core-shell structure, consisting of a core (core particle) and a coating layer (shell layer) that covers the core. Here, the core-shell structure of the toner particles may consist of, for example, a core portion comprising a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer comprising a binder resin.

[0111] The volume-average particle size (D50v) of the toner particles is preferably 2 μm to 10 μm, and more preferably 4 μm to 8 μm.

[0112] The average particle size and particle size distribution indices of the toner particles are measured using the Coulter Multisizer II (manufactured by Beckman Coulter), and the electrolyte is measured using the ISOTON-II (manufactured by Beckman Coulter). For measurement, add 0.5 mg to 50 mg of the sample to be measured in 2 ml of a 5% aqueous solution of a surfactant (preferably sodium alkylbenzenesulfonate) as a dispersant. Add this to 100 ml to 150 ml of electrolyte. The electrolyte containing the suspended sample is dispersed in an ultrasonic disperser for 1 minute. The particle size distribution of particles with diameters between 2 μm and 60 μm is then measured using a Coulter Multisizer II with a 100 μm aperture. The number of particles sampled is 50,000. Based on the measured particle size distribution, a cumulative distribution of volume and number is drawn for each divided particle size range (channel) from the smallest diameter side. The particle size at which the cumulative total reaches 16% is defined as the volume particle size D16v and the number particle size D16p, the particle size at which the cumulative total reaches 50% is defined as the volume average particle size D50v and the cumulative number average particle size D50p, and the particle size at which the cumulative total reaches 84% ​​is defined as the volume particle size D84v and the number particle size D84p. Using these, the volume particle size distribution index (GSDv) is (D84v / D16v) 1 / 2 The GSDp index is (D84p / D16p) 1 / 2 It is calculated as follows.

[0113] The average circularity of the toner particles is preferably 0.94 to 1.00, and more preferably 0.95 to 0.98.

[0114] The average circularity of toner particles is determined by (circular equivalent perimeter) / (perimeter) [(perimeter of a circle with the same projected area as the particle image) / (perimeter of the particle projection image)]. Specifically, it is a value measured by the following method. First, the toner particles to be measured are collected by suction, a flattened flow is formed, and a still image of the particles is captured by instantaneous strobe flashing. This particle image is then analyzed using a flow-type particle image analyzer (FPIA-3000 manufactured by Sysmex Corporation). The number of samples used to determine the average circularity is 3500. If the toner contains external additives, the toner (developer) to be measured is dispersed in water containing a surfactant, and then ultrasonic treatment is performed to obtain toner particles from which the external additives have been removed.

[0115] <External additives> The toner according to this embodiment preferably contains other external additives, as described above. Other external additives include, for example, inorganic oxide particles. Examples of inorganic oxide particles include particles of SiO2, TiO2, Al2O3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, K2O·(TiO2)n, Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, and MgSO4. Among the above, TiO2 particles (titania particles) or SiO2 particles (silica particles) are preferred as inorganic oxide particles.

[0116] From the viewpoint of improving toner fluidity, the number-average particle size of inorganic oxide particles is preferably 5 nm to 50 nm, and more preferably 10 nm to 40 nm.

[0117] The number-average particle size of inorganic oxide particles is determined as follows. (1) The toner is dispersed in methanol, stirred at room temperature (23°C), and then treated in an ultrasonic bath to separate the external additive from the toner. Subsequently, the toner particles are settled by centrifugation, and the dispersion containing the external additive is collected. After that, the methanol is removed by distillation, and the external additive is extracted. (2) The external additive is dispersed in resin particles (polyester, weight-average molecular weight Mw=50000) with a volume-average particle diameter of 100 μm. (3) The resin particles in which the external additive is dispersed are subjected to an energy-dispersive X-ray analyzer (EDX analyzer) (Horiba, Ltd., EMAX Evolution X-Max 80mm) 2 Observation is performed using a scanning electron microscope (SEM) (Hitachi High-Technologies, S-4800) equipped with a 3D filter, and images are captured at a magnification of 40,000x. At this time, EDX analysis is performed to identify more than 300 primary inorganic oxide particles within a single field of view, based on the presence of atoms (Si, Ti, etc.) contained in each inorganic oxide particle. The SEM is observed with an acceleration voltage of 15kV, emission current of 20μA, and a WD of 15mm, and the EDX analysis is performed under the same conditions with a detection time of 60 minutes. (4) The obtained images are imported into an image analysis device (LUZEXIII, manufactured by Nireco Corporation), and the area of ​​each particle is determined by image analysis. (5) From these measured area values, the particle diameter of each inorganic oxide particle is determined as the equivalent diameter of a circle. (6) Select 100 particles with an equivalent circle diameter of less than 80 nm. For the selected particles, plot the cumulative distribution of the equivalent circle diameter from the smallest diameter side, and define the particle diameter at which the cumulative distribution reaches 50% as the number-average particle diameter of the inorganic oxide particles.

[0118] The surface of the inorganic oxide particles used as an external additive should preferably be subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic oxide particles in a hydrophobic treatment agent. The hydrophobic treatment agent is not particularly limited, but examples include silane-based coupling agents, silicone oil, titanate-based coupling agents, and aluminum-based coupling agents. These may be used individually or in combination of two or more. The amount of hydrophobic treatment agent is typically, for example, 1 to 10 parts by mass per 100 parts by mass of inorganic oxide particles.

[0119] Examples of external additives include inorganic oxide particles, resin particles (such as polystyrene, polymethyl methacrylate (PMMA), and melamine resin), and cleaning activators (for example, fluorine-based high molecular weight particles).

[0120] As for the amount of other external additives such as inorganic oxide particles, for example, 0.01% by mass or more and 5% by mass or less relative to the toner particles is preferred, and 0.01% by mass or more and 2.0% by mass or less is more preferred.

[0121] <Toner manufacturing method> Next, a description of the toner manufacturing method according to this embodiment will be given. The toner according to this embodiment is obtained by manufacturing toner particles and then adding external additives (specifically, fatty acid metal salt particles, antioxidant particles, inorganic oxide particles, etc.) to the toner particles.

[0122] Toner particles may be manufactured by either a dry process (e.g., kneading and grinding method) or a wet process (e.g., agglomeration, suspension polymerization, dissolution and suspension method). There are no particular limitations on the manufacturing method of toner particles, and any well-known method may be used.

[0123] In this embodiment, the toner is produced, for example, by adding an external additive to the obtained dried toner particles and mixing them. Mixing can be performed using, for example, a V-blender, a Henschel mixer, a Redigge mixer, etc. Furthermore, if necessary, coarse particles of the toner may be removed using a vibrating screen separator, a wind screen separator, etc.

[0124] [Career] The carrier is not particularly limited and can be any known carrier. Examples of carriers include coated carriers in which a coating resin is applied to the surface of a core material made of magnetic powder; magnetic powder dispersed carriers in which magnetic powder is dispersed and blended in a matrix resin; and resin-impregnated carriers in which resin is impregnated into porous magnetic powder. Furthermore, magnetic powder dispersed carriers and resin-impregnated carriers may be carriers in which the constituent particles of the carrier are used as a core material and coated with a coating resin.

[0125] Examples of magnetic powders include magnetic metals such as iron, nickel, and cobalt, and magnetic oxides such as ferrite and magnetite.

[0126] Examples of coating resins and matrix resins include polyethylene, polypropylene, polystyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl ether, polyvinyl ketone, vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid ester copolymer, straight silicone resin or modified thereof containing organosiloxane bonds, fluororesin, polyester, polycarbonate, phenolic resin, epoxy resin, etc. The coating resin and matrix resin may also contain conductive particles or other additives. Examples of conductive particles include metals such as gold, silver, and copper, as well as carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0127] To coat the surface of the core material with a coating resin, methods include coating with a coating layer-forming solution prepared by dissolving the coating resin and, if necessary, various additives in a suitable solvent. The solvent is not particularly limited and should be selected considering the coating resin used, its suitability for application, etc. Specific resin coating methods include the immersion method, in which the core material is immersed in the coating layer-forming solution; the spray method, in which the coating layer-forming solution is sprayed onto the surface of the core material; the fluidized bed method, in which the coating layer-forming solution is sprayed while the core material is suspended by fluidized air; and the kneader coater method, in which the carrier core material and the coating layer-forming solution are mixed in a kneader coater and the solvent is removed.

[0128] In a two-component developer, the mixing ratio (mass ratio) of toner and carrier is preferably toner:carrier = 1:100 to 30:100, and more preferably 3:100 to 20:100. [Examples]

[0129] The following describes embodiments of this disclosure, but this disclosure is not limited to these embodiments. In the following description, unless otherwise specified, "parts" and "%" all refer to mass.

[0130] (Preparation of antioxidant particles) Various particles of the following phenolic antioxidants A1, A2, phosphorus-based antioxidant B, sulfur-based antioxidant C, and hindered amine-based antioxidant D were prepared.

[0131] [ka]

[0132] (Preparation of solid lubricant (a)) A mixture of 9 parts by mass of zinc stearate particles, 0.5 parts by mass of antioxidant A1 particles, and 0.5 parts by mass of antioxidant C particles was placed in a mold of a compression molding apparatus (manufactured by SHIMADZU Co., Ltd., product name: manual hydraulic pump), and compression molded under conditions of 23°C and 55% RH to obtain a solid lubricant (a) as a compression molded body. The obtained solid lubricant (a) had dimensions of 10 mm × 10 mm × 340 mm.

[0133] <Toner production> -Preparation of polyester resin particle dispersion- (Preparation of amorphous polyester resin particle dispersion (A)) Terephthalic acid: 70 parts Fumaric acid: 30 parts • Ethylene glycol: 45 parts • 1,5-Pentanediol: 46 parts The above materials were charged into a flask equipped with a stirrer, nitrogen inlet tube, temperature sensor, and rectification column. The temperature was raised to 220°C over 1 hour under a nitrogen gas stream, and 1 part titanium tetraethoxide was added to 100 parts of the total materials. The temperature was raised to 240°C over 0.5 hours while distilling off the generated water, and the dehydration condensation reaction was continued at this temperature for 1 hour, after which the reactants were cooled. In this way, a polyester resin with a weight-average molecular weight of 9500 and a glass transition temperature of 62°C was synthesized.

[0134] In a container equipped with temperature control and nitrogen purging means, 40 parts of ethyl acetate and 25 parts of 2-butanol were added to form a mixed solvent. Then, 100 parts of polyester resin were gradually added and dissolved. A 10% aqueous ammonia solution (equivalent to 3 times the molar ratio of the acid value of the resin) was added and stirred for 30 minutes. Next, the container was purged with dry nitrogen, and the temperature was maintained at 40°C. While stirring the mixture, 400 parts of deionized water were added dropwise at a rate of 2 parts / minute to emulsify it. After the dropwise addition was complete, the emulsion was returned to 25°C to obtain a resin particle dispersion in which resin particles with a volume average particle size of 200 nm were dispersed. Deionized water was added to the resin particle dispersion to adjust the solid content to 20% to obtain amorphous polyester resin particle dispersion (A).

[0135] (Preparation of crystalline polyester resin particle dispersion (C)) • 1,10-Decanedicarboxylic acid: 98 parts Sodium dimethyl-5-sulfonate isophthalate: 24 parts • 1,9-nonanediol: 100 parts • Dibutyltin oxide (catalyst): 0.3 parts After placing the above components into a heated and dried three-necked flask, the air inside the container was removed by reducing the pressure to create an inert atmosphere with nitrogen gas, and the mixture was stirred and refluxed at 180°C for 5 hours by mechanical stirring. Subsequently, the temperature was gradually increased to 230°C under reduced pressure and stirred for 2 hours until a viscous state was reached, at which point it was air-cooled to stop the reaction and obtain a crystalline polyester resin. Molecular weight measurement (in polystyrene equivalent) showed that the weight-average molecular weight (Mw) of the crystalline polyester resin was 9700, and the melting temperature was 78°C.

[0136] 90 parts of the obtained crystalline polyester resin, 1.8 parts of the anionic surfactant Neogen RK (Daiichi Kogyo Seiyaku), and 210 parts of ion-exchanged water were heated to 100°C and dispersed using an IKA Ultra-Turrax T50. The dispersion treatment was then carried out for 1 hour using a pressure-discharge type Gorin homogenizer to obtain a crystalline polyester resin particle dispersion (C) with a volume-average particle size of 200 nm and a solid content of 20%.

[0137] (Preparation of mold release agent particle dispersion) • Paraffin wax (HNP-9, manufactured by Nippon Seiro Co., Ltd.): 100 units • Anionic surfactant (Neogen RK, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 1 part • Ion-exchanged water: 350 units The above materials were mixed and heated to 100°C, dispersed using a homogenizer (IKA Ultra-Turrax T50), and then dispersed again using a Manton-Gorin high-pressure homogenizer (Gorin), to obtain a release agent particle dispersion (solid content 20%) in which release agent particles with a volume average particle size of 200 nm were dispersed.

[0138] (Preparation of a dispersion of coloring agent particles) • Magenta pigment (Pigment Red 122, manufactured by DIC Corporation): 50 copies • Anionic surfactant Neogen RK (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.): 5 parts • Ion-exchanged water: 192.9 parts The above components were mixed and treated with an ultimateizer (manufactured by Sugino Machine Co., Ltd.) at 240 MPa for 10 minutes to prepare a dispersion of colorant particles (solid content: 20%).

[0139] (Preparation of toner particles (T1)) • Ion-exchanged water: 200 bottles • Amorphous polyester resin particle dispersion (A): 150 parts • Crystalline polyester resin particle dispersion (C): 10 parts • Coloring agent particle dispersion: 15 parts • Release agent particle dispersion: 10 parts • Anionic surfactant (TaycaPower): 2.8 parts The above materials were placed in a round stainless steel flask, and 0.1N nitric acid was added to adjust the pH to 3.5. Then, an aqueous solution of polyaluminum chloride (PAC, manufactured by Oji Paper Co., Ltd.: 30% powder) was added, which consisted of 2.0 parts of PAC dissolved in 30 parts of deionized water. The mixture was dispersed at 30°C using a homogenizer (IKA Ultra-Turrax T50), and then heated in a heating oil bath to 45°C until the volume-average particle size reached 4.8 μm. Subsequently, 60 parts of amorphous polyester resin particle dispersion (A) were added and held for 30 minutes. After the volume-average particle size reached 5.2 μm, another 60 parts of amorphous polyester resin particle dispersion (A) were added and held for 30 minutes. Next, 20 parts of 10% NTA (nitrilotriacetic acid) metal salt aqueous solution (Kirest 70: manufactured by Kirest Co., Ltd.) were added, and then the pH was adjusted to 9.0 using a 1N sodium hydroxide aqueous solution. Subsequently, 1.0 part of anionic surfactant (TaycaPower) was added, and the mixture was heated to 85°C while continuing to stir, and held for 5 hours. After that, it was cooled to 20°C at a rate of 20°C / min, filtered, thoroughly washed with deionized water, and dried to obtain toner particles (T1) with a volume average particle size of 6.0 μm.

[0140] (Preparation of toner (T1)) 100 parts of toner particles (T1), 0.2 parts of zinc stearate particles (ZnSt), and 0.022 parts of antioxidant A1 particles were mixed and mixed for 30 seconds at a rotation speed of 13,000 rpm using a sample mill. The mixture was sieved using a vibrating sieve with a mesh size of 45 μm to obtain toner (T1).

[0141] (Preparation of toners (T2) to (T13), (TC1)) Each toner was obtained in the same manner as toner (T1), except that the type and amount of antioxidant particles were changed as shown in Table 1. Note that the "Content" in Table 1 * This indicates the percentage (by mass) of phenolic antioxidants relative to the total mass of antioxidants.

[0142] (Preparation of developers (T1) to (T13) and (TC1)) Ten parts of each toner and 100 parts of the resin-coated carrier described below were placed in a V-type blender and stirred for 20 minutes. Then, the mixture was sieved using a vibrating sieve with a mesh size of 212 μm to obtain the developer. Mn-Mg-Sr ferrite particles (average particle size 40 μm): 100 parts • Toluene: 14 parts • Polymethyl methacrylate: 2 parts • Carbon Black (VXC72: Cabot): 0.12 parts The above materials, excluding the ferrite particles, were mixed with glass beads (1 mm in diameter, in the same amount as toluene), and the mixture was stirred for 30 minutes at a rotation speed of 1200 rpm using a sand mill manufactured by Kansai Paint Co., Ltd. to obtain a dispersion. This dispersion and the ferrite particles were placed in a vacuum-degassed kneader, and dried under reduced pressure while stirring to obtain a resin-coated carrier.

[0143] [Examples 1-14 and Comparative Example 1] According to Table 1, the following image forming apparatus was prepared.

[0144] [evaluation] The developers obtained in each example were loaded (stored) into the developer unit of a modified Versant 2100Press manufactured by Fujifilm Business Innovation Co., Ltd. (modified to allow for the attachment and detachment of the lubricant application device), which is an image forming apparatus with the configuration shown in Figure 1, and evaluated as follows. The results are shown in Table 1. In Examples 1-13, the developer (T1)-(T13) contained toner with a solid lubricant consisting of zinc stearate particles and antioxidant particles as an external additive, and was filled into the developer unit. In the case of Example 14 (where a lubricant application device is provided), a developer (TC1) containing toner that does not contain antioxidant particles as an external additive was filled into the developer, and a solid lubricant (a), which is the molded body described above, was installed in the lubricant application device as a solid lubricant.

[0145] (Transferability to embossed paper) In the image forming apparatus described above, 10,000 magenta 50% halftone images were printed on A4-sized embossed paper (Lezac 66, manufactured by Tokushu Tokai Paper Co., Ltd.) under high temperature and high humidity conditions of 30°C and 80% RH. Then, magenta images were printed with five different image densities: 20%, 30%, 50%, 70%, and 90%. Of the five resulting images, the one with the most visible gaps was selected, and the number of gaps in that image was checked. Based on the gaps in the image, the transferability to embossed paper was evaluated according to the following criteria. -Evaluation Criteria- G1: No missing images. G2: There are missing elements in the image, either one or two. G3: There are missing elements in the image, with 3 to 5 missing elements. G4: There are missing elements in the image, with 6 to 9 missing elements. G5: There are missing elements in the image, and the number of missing elements is 10 or more.

[0146] [Table 1]

[0147] As shown in Table 1, the image forming apparatus of the example was found to have superior transferability to embossed paper compared to the image forming apparatus of the comparative example. [Explanation of symbols]

[0148] 1Y, 1M, 1C, 1K photoreceptors (examples of image retainers) 2Y, 2M, 2C, 2K Charging Rolls (Example of Charging Method) 3. Exposure apparatus (an example of electrostatic image formation means) 3Y, 3M, 3C, 3K laser beam 4Y, 4M, 4C, 4K developing apparatus (an example of a developing method) 5Y, 5M, 5C, 5K Primary Transfer Rolls (Example of Primary Transfer Method) 6Y, 6M, 6C, 6K Lubricant application device (an example of a lubricant application means) 7Y, 7M, 7C, 7K Photoreceptor Cleaning Device (Example of Cleaning Method) 8Y, 8M, 8C, 8K Toner Cartridges 10Y, 10M, 10C, 10K Image Forming Units 20. Intermediate transfer belt (an example of an intermediate transfer material) 22 Drive Roll 24 Support Rolls 26. Secondary transfer roll (an example of a secondary transfer means) 30 Intermediate Transfer Body Cleaning Apparatus 107 Photoreceptor (an example of an image-retaining element) 108 Charging Roll (Example of Charging Method) 109 Exposure apparatus (an example of a means for forming electrostatic images) 111 Developing apparatus (an example of a developing means) 112 Transfer device (an example of a transfer means) 113 Lubricant application device (an example of a lubricant application means) 114 Photoreceptor cleaning device (an example of a cleaning method) 115 Fixing device (an example of a fixing means) 116 Mounting Rail 117 cabinets 118 Aperture for exposure 200 Process Cartridges 300 Recording paper (an example of a recording medium) P Recording paper (an example of a recording medium)

Claims

1. An electrophotographic photoreceptor having a photosensitive layer, A charging means for charging the surface of the electrophotographic photoreceptor, A means for forming an electrostatic image on the surface of the charged electrophotographic photoreceptor, A developing means containing an electrostatic image developer including an electrostatic image developing toner, and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the electrostatic image developer, A transfer means for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, An image forming apparatus comprising and satisfying at least one of the following conditions (1) and (2). Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor. The aforementioned antioxidant includes a phenolic antioxidant and a sulfuric antioxidant. The phenolic antioxidant is at least one of the phenolic antioxidant represented by the following structural formula A1 and the phenolic antioxidant represented by the following structural formula A2. The aforementioned sulfur-based antioxidant is a sulfur-based antioxidant represented by the following structural formula C. 【Chemistry 1】

2. The image forming apparatus according to Claim 1, wherein the phenolic antioxidant is a phenolic antioxidant represented by the following structural formula A1, and the sulfuric antioxidant is a sulfuric antioxidant represented by the following structural formula C. 【Chemistry 2】

3. The image forming apparatus according to claim 1 or claim 2, wherein the content of the antioxidant in the solid lubricant is 5% by mass or more with respect to the total mass of the solid lubricant.

4. The image forming apparatus according to claim 1 or claim 2, wherein the content of the antioxidant in the solid lubricant is 10% by mass or more with respect to the total mass of the solid lubricant.

5. The image forming apparatus according to claim 1 or claim 2, wherein the content of the phenolic antioxidant is 30% by mass or more and 90% by mass or less based on the total mass of the antioxidant.

6. The image forming apparatus according to claim 1 or claim 2, wherein the content of the phenolic antioxidant is 50% by mass or more and 90% by mass or less based on the total mass of the antioxidant.

7. The image forming apparatus according to claim 1 or claim 2, wherein the content of the antioxidant in the solid lubricant is 1% by mass or more and 50% by mass or less with respect to the total mass of the solid lubricant.

8. The image forming apparatus according to claim 7, wherein the content of the phenolic antioxidant is 5% by mass or more and 90% by mass or less based on the total mass of the antioxidant.

9. An electrophotographic photoreceptor having a photosensitive layer, A charging means for charging the surface of the electrophotographic photoreceptor, A means for forming an electrostatic image on the surface of the charged electrophotographic photoreceptor, A developing means containing an electrostatic image developer including an electrostatic image developing toner, and developing the electrostatic image formed on the surface of the electrophotographic photoreceptor as a toner image using the electrostatic image developer, A transfer means for transferring the toner image formed on the surface of the electrophotographic photoreceptor to the surface of a recording medium, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, An image forming apparatus comprising and satisfying at least one of the following conditions (1) and (2). Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor. The content of the antioxidant in the solid lubricant is 5% by mass or more, relative to the total mass of the solid lubricant. The antioxidant comprises a phenolic antioxidant and one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants. The phenolic antioxidant is at least one of the phenolic antioxidant represented by the following structural formula A1 and the phenolic antioxidant represented by the following structural formula A2. The content of the phenolic antioxidant is 30% by mass or more and 90% by mass or less, relative to the total mass of the antioxidant. 【Transformation 3】

10. A developing means that contains an electrostatic image developer containing an electrostatic image developing toner, and develops the electrostatic image formed on the surface of an electrophotographic photoreceptor as a toner image using the electrostatic image developer, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, A process cartridge that is equipped with and satisfies at least one of the following conditions (1) and (2), and is detachable from an image forming apparatus. Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor. The aforementioned antioxidant includes a phenolic antioxidant and a sulfuric antioxidant. The phenolic antioxidant is at least one of the phenolic antioxidant represented by the following structural formula A1 and the phenolic antioxidant represented by the following structural formula A2. The aforementioned sulfur-based antioxidant is a sulfur-based antioxidant represented by the following structural formula C. 【Chemistry 4】

11. A developing means that contains an electrostatic image developer containing an electrostatic image developing toner, and develops the electrostatic image formed on the surface of an electrophotographic photoreceptor as a toner image using the electrostatic image developer, A cleaning means having a cleaning blade that contacts the surface of the electrophotographic photoreceptor and cleans the surface of the electrophotographic photoreceptor, A process cartridge that is equipped with and satisfies at least one of the following conditions (1) and (2), and is detachable from an image forming apparatus. Condition (1): The electrostatic image developing toner contains a solid lubricant comprising a fatty acid metal salt and an antioxidant. Condition (2): The device comprises a coating means for applying a solid lubricant containing a fatty acid metal salt and an antioxidant onto the electrophotographic photoreceptor. The content of the antioxidant in the solid lubricant is 5% by mass or more, relative to the total mass of the solid lubricant. The antioxidant comprises a phenolic antioxidant and one or more selected from the group consisting of phosphorus-based antioxidants, sulfur-based antioxidants, and hindered amine-based antioxidants. The phenolic antioxidant is at least one of the phenolic antioxidant represented by the following structural formula A1 and the phenolic antioxidant represented by the following structural formula A2. The content of the phenolic antioxidant is 30% by mass or more and 90% by mass or less, relative to the total mass of the antioxidant. 【Transformation 5】

Images