Image forming apparatus

Abstract

To provide an image forming apparatus which is excellent in wear resistance of a photoreceptor and wear resistance of a cleaning blade and hardly causes filming on the surface of the photoreceptor.SOLUTION: The image forming apparatus includes a photoreceptor, a charging device, an electrostatic latent image forming device, a developing device, a transfer device, and a photoreceptor cleaning device, wherein the photoreceptor has an inorganic surface layer containing a Group 13 element and an oxygen element, the cleaning blade has an impregnated cured layer of an isocyanate compound and a silicone-modified acrylic polymer in a contact portion contacting the surface of the photoreceptor, the cleaning blade has a 100% modulus of 13 MPa or more and 22 MPa or less, a tip angle of 60 degrees or more and 87 degrees or less, and an action angle of the cleaning blade with respect to the surface of the photoreceptor of 8 degrees or more and 30 degrees or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to an image forming apparatus. [Background technology]

[0002] Patent Document 1 discloses an electrophotographic image forming system that includes at least the steps of forming an electrostatic latent image on a photoreceptor, developing the image using toner for developing the electrostatic image, and removing the toner for developing the electrostatic image by pressing the ridgeline of a cleaning blade against the surface of the photoreceptor, wherein the surface layer of the photoreceptor contains a thermoplastic resin with electron-accepting properties, the toner particles that make up the toner for developing the electrostatic image contain a fatty acid metal salt as an external additive, and the ridgeline of a cleaning blade with an edge angle of 90° to 130° is pressed against the surface of the photoreceptor, and the effective contact angle of the cleaning blade is 7° to 20°.

[0003] Patent Document 2 discloses a cleaning blade that is made of a polyurethane rubber material, has an impregnated and cured layer of an isocyanate compound at the contact portion that comes into contact with the member to be cleaned, and has a Young's modulus at the contact portion of 14 MPa or more and 25 MPa or less and a tip angle of 55 degrees or more and 80 degrees or less.

[0004] Patent Document 3 discloses an image forming apparatus equipped with a cleaning blade having a 100% modulus at a temperature of 23° C. of 17 MPa or more and 23 MPa or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-106478 [Patent Document 2] Japanese Patent Publication No. 2024-017062 [Patent Document 3] Japanese Patent Publication No. 2024-027443 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide an image forming apparatus in which the abrasion resistance of the photoreceptor and the abrasion resistance of the cleaning blade are excellent and filming is unlikely to occur on the surface of the photoreceptor. [Means for solving the problem]

[0007] Specific means for solving the above problems include the following aspects. <1> A photoreceptor; a charging device that charges the surface of the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoreceptor; a developing device that contains a developer containing toner and develops the electrostatic latent image formed on the surface of the photoreceptor to form a toner image; a transfer device that transfers the toner image onto a surface of a recording medium; a cleaning device having a cleaning blade that comes into contact with the surface of the photoreceptor and cleans the surface of the photoreceptor; the photoreceptor has an inorganic surface layer containing a Group 13 element and an oxygen element, the cleaning blade has an impregnated and cured layer of an isocyanate compound and a silicone-modified acrylic polymer at a contact portion that comes into contact with the surface of the photoreceptor, the 100% modulus of the cleaning blade is 13 MPa or more and 22 MPa or less, The tip angle of the cleaning blade is 60 degrees or more and 87 degrees or less, the operating angle of the cleaning blade relative to the surface of the photoreceptor is 8 degrees or more and 30 degrees or less; Image forming device. <2> a coefficient of dynamic friction between the surface of the photoreceptor and the contact portion of the cleaning blade is 0.3 or more and 0.6 or less; <1> 2. The image forming apparatus according to claim 1 . <3> the 100% modulus of the cleaning blade is 13 MPa or more and 18 MPa or less; <1> or <2> 2. The image forming apparatus according to claim 1 . <4> The tip angle of the cleaning blade is 80 degrees or more and 85 degrees or less. <1> ~ <3> 10. The image forming apparatus according to claim 9, wherein: <5> the inorganic surface layer of the photoreceptor is a layer containing a Group 13 element oxide; <1> ~ <4> 10. The image forming apparatus according to claim 9, wherein: <6> the inorganic surface layer of the photoreceptor is a gallium oxide layer; <1> ~ <5> 10. The image forming apparatus according to claim 9, wherein: <7> The base material of the cleaning blade is polyurethane. <1> ~ <6> 10. The image forming apparatus according to claim 9, wherein: [Effects of the Invention]

[0008] <1> , <5> , <6> or <7> According to the present invention, an image forming apparatus is provided which is superior in abrasion resistance of the photoreceptor and abrasion resistance of the cleaning blade compared to an image forming apparatus equipped with a photoreceptor without an inorganic surface layer and / or a cleaning blade without an impregnated cured layer, and which is less likely to produce filming on the surface of the photoreceptor compared to an image forming apparatus in which the 100% modulus of the cleaning blade is less than 13 MPa or more than 22 MPa, or the tip angle of the cleaning blade is less than 60 degrees or more than 87 degrees, or the working angle of the cleaning blade relative to the surface of the photoreceptor is less than 8 degrees or more than 30 degrees. <2> According to the present invention, an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the coefficient of dynamic friction between the surface of the photoreceptor and the contact portion of the cleaning blade is less than 0.3, and an image forming apparatus is provided in which the wear resistance of the photoreceptor and the wear resistance of the cleaning blade are superior to those in an image forming apparatus in which the coefficient of dynamic friction between the surface of the photoreceptor and the contact portion of the cleaning blade is more than 0.6. <3> According to this, an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the 100% modulus of the cleaning blade is less than 13 MPa or more than 18 MPa. <4> According to the present invention, an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the tip angle of the cleaning blade is less than 80 degrees or more than 85 degrees. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 2 is a schematic diagram illustrating an example of a cleaning blade according to the present embodiment. [Figure 2] FIG. 2 is a schematic diagram illustrating an example of a cleaning blade according to the present embodiment. [Figure 3] 1 is a schematic configuration diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 4] FIG. 10 is a schematic configuration diagram illustrating another example of an image forming apparatus according to the present embodiment. [Figure 5] FIG. 2 is a partial cross-sectional view showing an example of a layer structure of a photoreceptor according to the present embodiment. [Figure 6] FIG. 4 is a partial cross-sectional view showing another example of the layer structure of the photoreceptor according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0023] The following describes embodiments of the present disclosure. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0011] In the present disclosure, a numerical range indicated using "to" indicates a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in this disclosure, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit value of that numerical range may be replaced with a value shown in the examples.

[0012] In the present disclosure, the term "step" includes not only an independent step but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.

[0013] When embodiments of the present disclosure are described with reference to the drawings, the configuration of the embodiment is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in each drawing are conceptual, and the relative size relationships between the components are not limited to these.

[0014] In the present disclosure, each component may contain multiple corresponding substances. When referring to the amount of each component in a composition in the present disclosure, if multiple substances corresponding to each component are present in the composition, the total amount of the multiple substances present in the composition is meant unless otherwise specified. In the present disclosure, the composition may contain multiple types of particles corresponding to each component. When multiple types of particles corresponding to each component are present in the composition, the particle size of each component means the value for a mixture of the multiple types of particles present in the composition, unless otherwise specified.

[0015] In the present disclosure, alkyl groups and alkylene groups include any of linear, branched and cyclic groups, unless otherwise specified. In the present disclosure, a hydrogen atom in an organic group, aromatic ring, linking group, alkyl group, alkylene group, aryl group, aralkyl group, alkoxy group, aryloxy group, or the like may be substituted with a halogen atom. In the present disclosure, when a compound is represented by a structural formula, the symbols (C and H) representing carbon atoms and hydrogen atoms in the hydrocarbon group and / or hydrocarbon chain may be omitted. In the present disclosure, "(meth)acrylic" is an expression that includes both acrylic and methacrylic, and "(meth)acrylate" is an expression that includes both acrylate and methacrylate. In the present disclosure, the term "structural unit" of a copolymer or resin has the same meaning as a monomer unit.

[0016] In this disclosure, the term "photoreceptor" refers to an "electrophotographic photoreceptor." In this disclosure, the "axial direction" of a photoreceptor means the direction in which the rotation axis of the photoreceptor extends, and the "circumferential direction" of a photoreceptor means the rotation direction of the photoreceptor.

[0017] <Image forming device> The image forming apparatus according to this embodiment includes: A photoreceptor; a charging device for charging the surface of the photoreceptor; an electrostatic latent image forming device that forms an electrostatic latent image on the surface of a charged photoreceptor; a developing device that contains a developer containing toner and develops the electrostatic latent image formed on the surface of the photosensitive member to form a toner image; a transfer device that transfers the toner image onto the surface of a recording medium; and a cleaning device having a cleaning blade that comes into contact with the surface of the photoreceptor and cleans the surface of the photoreceptor.

[0018] The image forming apparatus according to this embodiment includes: the photoreceptor has an inorganic surface layer containing a Group 13 element and an oxygen element; the cleaning blade has an impregnated and cured layer of an isocyanate compound and a silicone-modified acrylic polymer at a contact portion that comes into contact with the surface of the photoreceptor; The 100% modulus of the cleaning blade is 13 MPa or more and 22 MPa or less, The tip angle of the cleaning blade is between 60 degrees and 87 degrees, The operating angle of the cleaning blade relative to the surface of the photoreceptor is 8 degrees or more and 30 degrees or less.

[0019] In the present disclosure, the 100% modulus of the cleaning blade is a value measured by the following measurement method. Tensile tests are conducted in accordance with JIS K6251:2017, "Vulcanized and thermoplastic rubber - Determination of tensile properties." The test specimen is a No. 3 dumbbell. Prior to the tensile test, the specimen is placed in an environment with a temperature of 23°C and a relative humidity of 55% for at least one day. In an environment with a temperature of 23°C and a relative humidity of 55%, the test is conducted at a tensile speed of 500 mm / min using a fully automatic tensile testing machine, the Strograph AE Elastomer (Toyo Seiki Seisakusho Co., Ltd.), and the stress at 100% elongation is measured. The stress at 100% elongation divided by the initial cross-sectional area of ​​the specimen is the 100% modulus. The 100% modulus values ​​of multiple specimens are then arithmetically averaged. The method for collecting the test specimens is as follows. The length direction of the cleaning blade (parallel to the axial direction of the photoreceptor) is aligned with the length direction of the test piece (pulling direction), and the test piece is taken. The thickness of the test piece is the thickness of the cleaning blade. The number of test pieces is 2, 3, or 4, depending on the length of the cleaning blade.

[0020] The tip angle and action angle of the cleaning blade in the present disclosure will be explained with reference to FIGS. 1 and 2 are schematic diagrams showing an example of a cleaning blade provided in a photosensitive member cleaning device of an image forming apparatus according to this embodiment. FIG. 1 shows the cleaning blade 30 in a state where it is not in contact with the outer peripheral surface of the photoreceptor 7. FIG. 2 shows a state in which the cleaning blade 30 shown in FIG. 1 is in contact with the outer peripheral surface of the photoreceptor 7 to perform cleaning. 1 and 2 are cross-sectional views parallel to the rotation direction of the photosensitive member 7 (that is, the direction of arrow A).

[0021] A support member 70 is joined to the cleaning blade 30. A pressure member (not shown) is joined to the support member 70. The pressure member presses the support member 70, thereby pressing the cleaning blade 30 against the photoreceptor 7.

[0022] The corner 31E of the cleaning blade 30 and its vicinity are contact portions that come into contact with the outer peripheral surface of the rotating photoreceptor 7 and clean the surface of the photoreceptor 7. The tip angle of the cleaning blade 30 is the angle θ of the corner 31E when the blade is not in contact with the outer peripheral surface of the photosensitive member .

[0023] When the cleaning blade 30 cleans the photoreceptor 7, the cleaning blade 30 is pressed against the photoreceptor 7, and therefore at least the tip thereof bends and forms an arc. The angle formed by the tangent to the cleaning blade 30 and the tangent to the photoreceptor 7, which pass through the contact point between the cleaning blade 30 and the photoreceptor 7 (the downstream edge of the contact point), is the action angle α.

[0024] The image forming apparatus according to this embodiment has excellent abrasion resistance of the photoreceptor and the cleaning blade, and is less susceptible to filming (the formation of a coating) on ​​the surface of the photoreceptor. The mechanism behind this is thought to be as follows.

[0025] Photoreceptors having an inorganic surface layer and cleaning blades having an impregnated hardened layer at the contact portion with the photoreceptor are both known. The photoreceptor has low dynamic friction on its outer circumferential surface. The cleaning blade also has low dynamic friction at the contact point with the photoreceptor. Therefore, when the photoreceptor and cleaning blade are combined, wear on both components is effectively suppressed, and a dramatic increase in their service life can be expected. However, the above combination has an extremely low frictional resistance between the photoreceptor and the cleaning blade, which causes the cleaning blade to slip on the photoreceptor and results in insufficient cleaning performance, which in turn causes the toner external additives to slip through the cleaning blade, resulting in filming on the surface of the photoreceptor due to the external additives. The image forming apparatus according to this embodiment solves the above problem by using the 100% modulus and tip angle of the cleaning blade and the action angle of the cleaning blade relative to the surface of the photoreceptor.

[0026] In this embodiment, the 100% modulus of the cleaning blade is 13 MPa or more and 22 MPa or less. If the 100% modulus of the cleaning blade is less than 13 MPa, the mechanical strength of the cleaning blade is insufficient, and the contact portion of the cleaning blade turns over, allowing the external additive to slip through and causing filming on the surface of the photoreceptor. From the viewpoint of suppressing this phenomenon, the 100% modulus of the cleaning blade is 13 MPa or more, preferably 14 MPa or more, and more preferably 15 MPa or more. If the 100% modulus of the cleaning blade exceeds 22 MPa, the mechanical strength of the cleaning blade is too strong, and the contact portion of the cleaning blade cannot be pressed sufficiently against the photoreceptor surface, causing external additives to slip through and filming to occur on the photoreceptor surface. From the viewpoint of suppressing this phenomenon, the 100% modulus of the cleaning blade is 22 MPa or less, preferably 20 MPa or less, and more preferably 18 MPa or less.

[0027] The 100% modulus of the cleaning blade can be controlled, for example, by using urethane rubber as the base material of the cleaning blade and by adjusting the content ratio of the hard segment and the soft segment contained in the urethane rubber.

[0028] In this embodiment, the tip angle of the cleaning blade is equal to or greater than 60 degrees and equal to or less than 87 degrees. If the tip angle of the cleaning blade is less than 60 degrees, the contact portion of the cleaning blade will turn over, allowing the external additive to slip through and causing filming on the surface of the photoreceptor. From the viewpoint of suppressing this phenomenon, the tip angle of the cleaning blade is 60 degrees or more, preferably 70 degrees or more, more preferably 75 degrees or more, and even more preferably 80 degrees or more. If the tip angle of the cleaning blade exceeds 87 degrees, the contact portion of the cleaning blade will slide on the photoreceptor, causing external additives to slip through and filming to occur on the surface of the photoreceptor. From the viewpoint of suppressing this phenomenon, the tip angle of the cleaning blade is 87 degrees or less, and preferably 85 degrees or less.

[0029] The tip angle of the cleaning blade can be controlled by processing the tip of the blade substrate, for example, by laser processing or grinding.

[0030] In this embodiment, the operating angle of the cleaning blade relative to the surface of the photoreceptor is 8 degrees or more and 30 degrees or less. If the working angle of the cleaning blade is less than 8 degrees, the contact portion of the cleaning blade will not be pressed sufficiently against the photoreceptor surface, causing external additives to slip through and filming to occur on the photoreceptor surface. From the viewpoint of suppressing this phenomenon, the working angle of the cleaning blade is 8 degrees or more, preferably 10 degrees or more, and more preferably 12 degrees or more. If the working angle of the cleaning blade exceeds 30 degrees, the contact portion of the cleaning blade will turn over, allowing the external additive to slip through and causing filming on the surface of the photoreceptor. From the viewpoint of suppressing this phenomenon, the working angle of the cleaning blade is 30 degrees or less, and preferably 28 degrees or less.

[0031] The action angle of the cleaning blade relative to the surface of the photoreceptor can be controlled by the angle at which the cleaning blade contacts the photoreceptor and the pressure with which it is pressed.

[0032] In the image forming apparatus according to the present embodiment, it is preferable that the coefficient of dynamic friction between the surface of the photosensitive member and the contact portion of the cleaning blade is 0.3 or more and 0.6 or less. When the dynamic friction coefficient is 0.3 or more, the contact portion of the cleaning blade exhibits a sufficient cleaning function, and the occurrence of filming on the surface of the photoreceptor is suppressed. From the viewpoint of suppressing the occurrence of filming on the surface of the photoreceptor, the dynamic friction coefficient is more preferably 0.4 or more, and even more preferably 0.5 or more. If the dynamic friction coefficient is 0.6 or less, the photosensitive member and cleaning blade are less susceptible to wear. From the viewpoint of excellent wear resistance of the photosensitive member and the cleaning blade, the dynamic friction coefficient is preferably 0.6 or less.

[0033] The dynamic friction coefficient between the contact portion of the cleaning blade and the surface of the photoreceptor can be controlled by the 100% modulus and tip angle of the cleaning blade, and the action angle of the cleaning blade relative to the surface of the photoreceptor.

[0034] In this embodiment, the dynamic friction coefficient between the surface of the photoreceptor and the contact portion of the cleaning blade is measured as follows. The cleaning blade is cut into 10 mm lengths at five approximately equal locations along its length (parallel to the axial direction of the photoreceptor) to obtain samples. The shape of the sample is roughly a rectangular parallelepiped (it is not a perfect rectangular parallelepiped, as the tip angle is between 60 and 87 degrees). Before testing, place the test piece in an environment with a temperature of 23°C and a relative humidity of 55% for at least one day. The following tests are carried out in an environment with a temperature of 23°C and a relative humidity of 55%. The photosensitive member is placed in a friction force measuring device, HEIDON Tribogear Type 14 (Shinto Scientific Co., Ltd.). A test piece is pressed against the photosensitive member. At this time, the contact point, operating angle, and pressing pressure of the test piece are set to the contact point, operating angle, and pressing pressure of an actual cleaning blade when it comes into contact with the surface of the photosensitive member. In other words, the state when the cleaning blade is in operation is reproduced. The photoconductor is rotated at a speed of 100 mm / sec. The rotation direction of the photoconductor is the same as that of an actual photoconductor. The dynamic friction force applied to the photoconductor during rotation is measured to determine the dynamic friction coefficient. The dynamic friction coefficients of the five test pieces are arithmetically averaged.

[0035] The pressure of the cleaning blade against the photoreceptor is preferably 1 gf / mm or more, more preferably 1.5 gf / mm or more, and even more preferably 2 gf / mm or more, from the viewpoint of suppressing filming on the surface of the photoreceptor. The pressure of the cleaning blade against the photosensitive member is preferably 5 gf / mm or less, more preferably 4 gf / mm or less, and even more preferably 3 gf / mm or less, from the viewpoint of stabilizing the behavior of the tip of the cleaning blade and ensuring cleaning performance.

[0036] The configuration of the image forming apparatus according to this embodiment will be described in detail below.

[0037] The image forming apparatus according to this embodiment includes a photosensitive member, a charging device, an electrostatic latent image forming device, a developing device, a transfer device, and a photosensitive member cleaning device. The image forming apparatus according to this embodiment may further include a fixing device that fixes the toner image transferred onto the surface of the recording medium, and a de-electrifying device that irradiates the surface of the photosensitive member with de-electrifying light to de-electrify the surface after the toner image is transferred and before it is charged. The image forming apparatus according to this embodiment may have a cartridge structure (process cartridge) in which the portion including the photosensitive member is detachably attached to the image forming apparatus.

[0038] The image forming apparatus according to the present embodiment may be a direct transfer type image forming apparatus in which a toner image formed on the surface of a photoreceptor is directly transferred to a recording medium, or an intermediate transfer type image forming apparatus in which a toner image formed on the surface of a photoreceptor is primarily transferred to the surface of an intermediate transfer body, and the toner image transferred to the surface of the intermediate transfer body is then secondarily transferred to the surface of a recording medium. The intermediate transfer type transfer device, for example, has an intermediate transfer body onto whose surface a toner image is transferred, a primary transfer device that primarily transfers the toner image formed on the surface of the photoreceptor onto the surface of the intermediate transfer body, and a secondary transfer device that secondarily transfers the toner image transferred to the surface of the intermediate transfer body onto the surface of a recording medium.

[0039] An example of an image forming apparatus according to the present embodiment will be described below, but the present invention is not limited to this. The main parts shown in the drawings will be described, and descriptions of other parts will be omitted.

[0040] FIG. 3 is a schematic diagram showing an example of the configuration of an image forming apparatus according to this embodiment. As shown in FIG. 3 , the image forming apparatus 100 according to this embodiment includes a process cartridge 300 having a photosensitive member 7, an exposure device 9 (an example of an electrostatic latent image forming device), a transfer device 40 (a primary transfer device), and an intermediate transfer member 50. In the image forming apparatus 100, the exposure device 9 is disposed in a position where it can expose the photosensitive member 7 through the opening of the process cartridge 300, and the transfer device 40 is disposed in a position facing the photosensitive member 7 with the intermediate transfer member 50 interposed therebetween, with a portion of the intermediate transfer member 50 being in contact with the photosensitive member 7. Although not shown, the image forming apparatus 100 also includes a secondary transfer device that transfers the toner image transferred to the intermediate transfer member 50 onto a recording medium (e.g., paper). The intermediate transfer member 50, the transfer device 40 (a primary transfer device), and the secondary transfer device (not shown) correspond to examples of transfer devices.

[0041] 3 integrally supports within a housing a photosensitive member 7, a charging device 8 (an example of a charging device), a developing device 11 (an example of a developing device), and a cleaning device 13 (an example of a photosensitive member cleaning device). The cleaning device 13 has a cleaning blade 131 (an example of a cleaning member), and the cleaning blade 131 is disposed so as to come into contact with the surface of the photosensitive member 7.

[0042] FIG. 3 shows an example of an image forming apparatus equipped with a fibrous member 132 (roll-shaped) that supplies lubricant 14 to the surface of photoreceptor 7, and a fibrous member 133 (flat brush-shaped) that assists cleaning, which may be arranged as needed.

[0043] FIG. 4 is a schematic diagram showing another example of the configuration of the image forming apparatus according to the present embodiment. The image forming apparatus 120 shown in Figure 4 is a tandem-type multi-color image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, the four process cartridges 300 are arranged in parallel on the intermediate transfer member 50, and one photosensitive member is used per color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100, except that it is a tandem-type apparatus.

[0044] Hereinafter, each configuration of the image forming apparatus according to this embodiment will be described.

[0045] [Photoreceptor] The photoreceptor 7 has, for example, a conductive substrate, a photosensitive layer disposed on the conductive substrate, and an inorganic surface layer disposed on the photosensitive layer. The photosensitive layer may be a laminated type photosensitive layer consisting of a charge generating layer and a charge transport layer, or may be a single-layer type photosensitive layer. Details of the photoreceptor will be described later.

[0046] [Charging device] The charging device 8 may be a contact type charger using, for example, a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, etc. The charging device 8 may also be a known charger such as a non-contact type roller charger, or a scorotron charger or corotron charger that uses corona discharge.

[0047] [Exposure equipment] Examples of the exposure device 9 include optical equipment that exposes the surface of the photoconductor 7 with light such as semiconductor laser light, LED light, or liquid crystal shutter light in a predetermined image. The wavelength of the light source is within the spectral sensitivity range of the photoconductor. The wavelength of semiconductor lasers is mainly near-infrared, with an oscillation wavelength around 780 nm. However, this wavelength is not limited to this, and lasers with an oscillation wavelength in the 600 nm range or blue lasers with an oscillation wavelength of 400 nm to 450 nm may also be used. Furthermore, for color image formation, a surface-emitting laser light source capable of outputting multiple beams is also effective.

[0048] [Developing device] The developing device 11 may be, for example, a general developing device that develops by contact or non-contact application of a developer. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and may be selected according to the purpose. For example, it may be a known developing device that has a function of applying a one-component developer or a two-component developer to the photoreceptor 7 using a brush, roller, or the like. Among these, a developing roller that holds the developer on its surface is preferred.

[0049] The developer used in the developing device 11 may be a one-component developer containing only toner, or a two-component developer containing toner and a carrier. The developer may be magnetic or non-magnetic. Details of the toner and developer will be described later.

[0050] [Cleaning device] The cleaning device 13 is a cleaning blade type device equipped with a cleaning blade 131. Details of the cleaning blade will be described later.

[0051] [Transfer device] Examples of the transfer device 40 include a contact type transfer charger using a belt, roller, film, rubber blade, etc., and a known transfer charger such as a scorotron transfer charger or corotron transfer charger that utilizes corona discharge.

[0052] [Intermediate transfer body] A belt-like material (intermediate transfer belt) containing semiconductively-conductive polyimide, polyamideimide, polycarbonate, polyarylate, polyester, rubber, etc. is used as the intermediate transfer body 50. The intermediate transfer body may be in the form of a drum other than a belt.

[0053] The operation of forming an image by image forming apparatus 100 shown in FIG. 3 will be described. The photoreceptor 7 rotates at a predetermined speed. A charging device 8 charges the surface of the photoreceptor 7 . The charged surface of the photoreceptor 7 is irradiated with, for example, a laser beam from the exposure device 9, and an electrostatic latent image is formed on the surface of the photoreceptor 7. The electrostatic latent image formed on the photoreceptor 7 moves to a development position as the photoreceptor 7 rotates. At the development position, the electrostatic latent image on the photoreceptor 7 is developed into a toner image by a developing device 11 and made visible. The toner image formed on the photoreceptor 7 moves to the primary transfer position as the photoreceptor 7 rotates. At the primary transfer position, a transfer bias is applied to the transfer device 40, and an electrostatic force from the photoreceptor 7 toward the transfer device 40 acts on the toner image on the photoreceptor 7, transferring the toner image to the intermediate transfer body 50. The intermediate transfer member 50 travels at a predetermined speed, and the toner image is transferred to a recording medium at the secondary transfer position by a secondary transfer device. The toner remaining on the surface of the photoreceptor 7 is removed and collected by the cleaning device 13.

[0054] The photoconductor included in the image forming apparatus according to this embodiment will be described in detail below. The cleaning blade of the photoconductor cleaning device included in the image forming apparatus according to this embodiment will also be described in detail. The toner and developer used in the developing device included in the image forming apparatus according to this embodiment will also be described in detail.

[0055] [Photoreceptor] An embodiment of the photoreceptor will be described with reference to FIGS.

[0056] Fig. 5 is a partial cross-sectional view schematically illustrating an example of the layer structure of a photoreceptor. Photoreceptor 10A shown in Fig. 5 has a structure in which an undercoat layer 2, a charge generation layer 3, a charge transport layer 4, and an inorganic surface layer 6 are laminated in this order on a conductive substrate 1, and the charge generation layer 3 and the charge transport layer 4 constitute a photosensitive layer 5 (a so-called laminated photosensitive layer). In photoreceptor 10A, the inorganic surface layer 6 is disposed in contact with the charge transport layer 4. Photoreceptor 10A may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generation layer 3. The undercoat layer 2 may or may not be present.

[0057] Fig. 6 is a partial cross-sectional view schematically illustrating another example of the layer structure of a photoreceptor. Photoreceptor 10B shown in Fig. 6 has a structure in which an undercoat layer 2, a single-layer photosensitive layer 5, and an inorganic surface layer 6 are laminated in this order on a conductive substrate 1. In photoreceptor 10B, the inorganic surface layer 6 is disposed in contact with the single-layer photosensitive layer 5. Photoreceptor 10B may have an intermediate layer (not shown) between the undercoat layer 2 and the charge generating layer 3. The undercoat layer 2 may or may not be present.

[0058] [Inorganic surface layer] The inorganic surface layer is an inorganic material layer containing a Group 13 element and oxygen. The Group 13 element is preferably at least one selected from the group consisting of boron, aluminum, gallium, and indium. The Group 13 element contained in the inorganic surface layer may be one type or two or more types.

[0059] In the inorganic surface layer, the total amount of Group 13 elements and oxygen elements in all elements is preferably 95 atomic % or more, more preferably 98 atomic % or more, and ideally 100 atomic %. Elemental analysis of the inorganic surface layer is performed by Rutherford Backscattering Spectrometry.

[0060] From the viewpoints of low friction, wear resistance, and electrical properties, the inorganic surface layer is preferably a layer containing a Group 13 element oxide. The Group 13 element oxide is preferably at least one selected from the group consisting of boron oxide, aluminum oxide, gallium oxide, and indium oxide. The Group 13 element oxide contained in the inorganic surface layer may be one type or two or more types.

[0061] From the viewpoints of low friction, wear resistance, and electrical properties, the inorganic surface layer is more preferably a gallium oxide layer or an aluminum oxide layer, and particularly preferably a gallium oxide layer.

[0062] The volume resistivity of the inorganic surface layer is 1.0×10 10It is preferable that the resistance is Ω·cm or more, and 1.0×10 11 It is more preferable that the resistivity is Ω·cm or more.

[0063] In the present disclosure, the volume resistivity of the inorganic surface layer is measured by the following method. The inorganic surface layer is peeled off from the photoreceptor to prepare a sample. The sample is clamped in the sample holder of an impedance analyzer (Toyo Corporation), and the resistance is measured at an AC voltage of 1 V and a frequency of 100 Hz, and calculated based on the electrode area and sample thickness.

[0064] Examples of methods for forming the inorganic surface layer include known vapor phase film formation methods such as plasma CVD (Chemical Vapor Deposition), metalorganic vapor phase epitaxy, molecular beam epitaxy, vapor deposition, sputtering, etc. For example, the inorganic surface layer can be formed using the plasma CVD film formation apparatus and film formation conditions described in JP 2014-191179 A.

[0065] From the viewpoint of abrasion resistance and electrical properties, the thickness of the inorganic surface layer is preferably 0.2 μm to 10 μm, more preferably 0.4 μm to 8 μm, and even more preferably 0.6 μm to 6 μm.

[0066] [Conductive substrate] Examples of conductive substrates include metal plates, metal drums, and metal belts containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.). Other examples of conductive substrates include paper, resin films, belts, etc. coated, vapor-deposited, or laminated with conductive compounds (e.g., conductive polymers, indium oxide, etc.), metals (e.g., aluminum, palladium, gold, etc.), or alloys. Here, "conductive" refers to a material having a volume resistivity of 1×10 13 This means that the resistance is less than Ω·cm.

[0067] When the photoreceptor is used in a laser printer, the surface of the conductive substrate is preferably roughened to a center line average roughness Ra of 0.04 μm to 0.5 μm inclusive in order to suppress interference fringes that occur when irradiated with laser light. When incoherent light is used as the light source, roughening to prevent interference fringes is not particularly necessary, but it is suitable for extending the life of the conductive substrate by suppressing defects caused by surface irregularities.

[0068] Examples of methods for roughening the surface include wet honing, which involves spraying an abrasive suspended in water onto the conductive substrate; centerless grinding, which involves pressing the conductive substrate against a rotating grinding wheel and continuously grinding the substrate; and anodizing.

[0069] As a method for roughening the surface, there may be mentioned a method in which, without roughening the surface of the conductive substrate, conductive or semiconductive powder is dispersed in a resin to form a layer on the surface of the conductive substrate, and the surface is roughened by the particles dispersed in the layer.

[0070] Anodizing is a surface roughening treatment that uses a metallic (e.g., aluminum) conductive substrate as the anode and anodizes it in an electrolyte solution to form an oxide film on the surface of the conductive substrate. Examples of electrolyte solutions include sulfuric acid solution and oxalic acid solution. However, the porous anodic oxide film formed by anodizing is chemically active in its original state, easily contaminated, and exhibits large resistance fluctuations depending on the environment. Therefore, it is preferable to perform a sealing treatment on the porous anodic oxide film, in which the micropores of the oxide film are sealed by volume expansion caused by hydration in pressurized steam or boiling water (with the addition of a metal salt such as nickel), converting the film into a more stable hydrated oxide.

[0071] The thickness of the anodic oxide film is preferably, for example, from 0.3 μm to 15 μm, inclusive, and within this range, the film tends to exhibit barrier properties against injection and also tends to suppress an increase in residual potential due to repeated use.

[0072] The conductive substrate may be subjected to a treatment with an acidic treatment solution or a boehmite treatment. Treatment with an acidic treatment solution is carried out, for example, as follows. First, an acidic treatment solution containing phosphoric acid, chromic acid, and hydrofluoric acid is prepared. The compounding ratios of phosphoric acid, chromic acid, and hydrofluoric acid in the acidic treatment solution are, for example, in the range of 10% by mass to 11% by mass for phosphoric acid, 3% by mass to 5% by mass for chromic acid, and 0.5% by mass to 2% by mass for hydrofluoric acid, with the total concentration of these acids preferably in the range of 13.5% by mass to 18% by mass. The treatment temperature is preferably, for example, 42°C to 48°C. The film thickness of the coating is preferably 0.3 μm to 15 μm.

[0073] The boehmite treatment is carried out, for example, by immersing the steel sheet in pure water at 90°C to 100°C for 5 to 60 minutes, or by contacting the steel sheet with heated steam at 90°C to 120°C for 5 to 60 minutes. The coating film preferably has a thickness of 0.1 μm to 5 μm. This may be further anodized using an electrolyte solution with low coating solubility, such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, or citrate.

[0074] [Sublayer] The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

[0075] For example, inorganic particles have a powder resistance (volume resistivity) of 1×10 2 Ω cm or more 1×10 11 Examples include inorganic particles with a particle size of Ω·cm or less. Among these, inorganic particles having the above resistance value are preferably metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zirconium oxide particles, with zinc oxide particles being particularly preferred.

[0076] The specific surface area of ​​inorganic particles measured by the BET method is, for example, 10 m 2 / g or more is preferable. The volume average particle size of the inorganic particles is, for example, 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

[0077] The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, more preferably 40% by mass or more and 80% by mass or less, relative to the binder resin.

[0078] The inorganic particles may be surface-treated, and two or more types of inorganic particles having different surface treatments or different particle sizes may be used in combination.

[0079] Examples of the surface treatment agent include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, a surfactant, etc. In particular, a silane coupling agent is preferred, and a silane coupling agent having an amino group is more preferred.

[0080] Examples of silane coupling agents having an amino group include, but are not limited to, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane.

[0081] Two or more silane coupling agents may be used in combination. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Examples of other silane coupling agents include, but are not limited to, vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0082] The surface treatment method using the surface treatment agent may be any known method, and may be either a dry method or a wet method.

[0083] The amount of the surface treatment agent to be used is preferably, for example, 0.5% by mass or more and 10% by mass or less relative to the inorganic particles.

[0084] Here, it is preferable that the undercoat layer contains an electron-accepting compound (acceptor compound) together with the inorganic particles, from the viewpoint of improving the long-term stability of the electrical properties and the carrier blocking property.

[0085] Examples of the electron-accepting compound include electron-transporting substances such as quinone compounds such as chloranil and bromoanil; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitro-9-fluorenone; oxadiazole compounds such as 2-(4-biphenyl)-5-(4-t-butylphenyl)-1,3,4-oxadiazole, 2,5-bis(4-naphthyl)-1,3,4-oxadiazole and 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole; xanthone compounds; thiophene compounds; diphenoquinone compounds such as 3,3',5,5'-tetra-t-butyldiphenoquinone; and benzophenone compounds. In particular, the electron-accepting compound is preferably a compound having an anthraquinone structure, such as a hydroxyanthraquinone compound, an aminoanthraquinone compound, or an aminohydroxyanthraquinone compound, and specifically, for example, anthraquinone, alizarin, quinizarin, anthrarphine, purpurin, or a derivative thereof.

[0086] The electron-accepting compound may be contained in the undercoat layer in a dispersed state together with the inorganic particles, or may be contained in a state of being attached to the surfaces of the inorganic particles.

[0087] The electron-accepting compound can be attached to the surface of the inorganic particles by, for example, a dry method or a wet method.

[0088] The dry method is a method in which, while stirring inorganic particles using a mixer or the like with high shear force, an electron-accepting compound is added dropwise, either directly or dissolved in an organic solvent, or sprayed together with dry air or nitrogen gas to adhere the electron-accepting compound to the surface of the inorganic particles. The electron-accepting compound is preferably added dropwise or sprayed at a temperature below the boiling point of the solvent. After the electron-accepting compound has been added dropwise or sprayed, baking may be performed at 100°C or higher. The baking temperature and time are not particularly limited as long as they achieve electrophotographic properties.

[0089] The wet method involves dispersing inorganic particles in a solvent using, for example, stirring, ultrasonic waves, a sand mill, an attritor, or a ball mill, while adding an electron-accepting compound. The mixture is stirred or dispersed, and then the solvent is removed to adhere the electron-accepting compound to the surfaces of the inorganic particles. The solvent can be removed, for example, by filtration or distillation. After solvent removal, baking may be performed at 100°C or higher. The baking temperature and time are not particularly limited as long as electrophotographic properties are obtained. In the wet method, moisture contained in the inorganic particles may be removed before adding the electron-accepting compound. Examples of such methods include a method of removing the moisture by stirring and heating in a solvent, and a method of removing the moisture by azeotropy with the solvent.

[0090] The attachment of the electron-accepting compound may be carried out before or after the inorganic particles are surface-treated with a surface-treating agent, or the attachment of the electron-accepting compound and the surface treatment with a surface-treating agent may be carried out simultaneously.

[0091] The content of the electron-accepting compound is, for example, 0.01% by mass or more and 20% by mass or less, and preferably 0.01% by mass or more and 10% by mass or less, based on the inorganic particles.

[0092] Examples of binder resins used in the undercoat layer include known polymer compounds such as acetal resins (e.g., polyvinyl butyral, etc.), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, unsaturated polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, alkyd resins, and epoxy resins; zirconium chelate compounds; titanium chelate compounds; aluminum chelate compounds; titanium alkoxide compounds; organic titanium compounds; and silane coupling agents. Examples of binder resins used in the undercoat layer include charge transporting resins having charge transporting groups, conductive resins (such as polyaniline), and the like.

[0093] Among these, the binder resin used in the undercoat layer is preferably a resin that is insoluble in the coating solvent of the upper layer, and in particular, a resin obtained by reacting at least one resin selected from the group consisting of thermosetting resins such as urea resins, phenolic resins, phenol-formaldehyde resins, melamine resins, urethane resins, unsaturated polyester resins, alkyd resins, and epoxy resins, and polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins with a curing agent is preferred. When two or more of these binder resins are used in combination, the mixing ratio is set as necessary.

[0094] The undercoat layer may contain various additives to improve electrical properties, environmental stability, and image quality. Examples of additives include known materials such as polycyclic condensation and azo electron transport pigments, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. Silane coupling agents are used for the surface treatment of inorganic particles as described above, and may also be added to the undercoat layer as an additive.

[0095] Examples of silane coupling agents as additives include vinyltrimethoxysilane, 3-methacryloxypropyl-tris(2-methoxyethoxy)silane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N,N-bis(2-hydroxyethyl)-3-aminopropyltriethoxysilane, and 3-chloropropyltrimethoxysilane.

[0096] Examples of zirconium chelate compounds include zirconium butoxide, zirconium ethyl acetoacetate, zirconium triethanolamine, acetylacetonate zirconium butoxide, ethyl acetoacetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, methacrylate zirconium butoxide, stearate zirconium butoxide, and isostearate zirconium butoxide.

[0097] Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-normal-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, titanium lactate ammonium salt, titanium lactate, titanium lactate ethyl ester, titanium triethanolamine, and polyhydroxytitanium stearate.

[0098] Examples of aluminum chelate compounds include aluminum isopropylate, monobutoxyaluminum diisopropylate, aluminum butyrate, diethylacetoacetate aluminum diisopropylate, and aluminum tris(ethylacetoacetate).

[0099] These additives may be used alone or as a mixture or polycondensate of a plurality of compounds.

[0100] The undercoat layer preferably has a Vickers hardness of 35 or more. The surface roughness (ten-point average roughness) of the undercoat layer is preferably adjusted to between 1 / (4n) (n is the refractive index of the upper layer) and 1 / 2 of the wavelength λ of the exposure laser used to suppress moiré images. Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. The surface of the undercoat layer may be polished to adjust the surface roughness. Examples of polishing methods include buffing, sandblasting, wet honing, and grinding.

[0101] The formation of the undercoat layer is not particularly limited, and a known formation method can be used. For example, the undercoat layer can be formed by forming a coating film of a coating liquid for forming the undercoat layer in which the above components are added to a solvent, drying the coating film, and heating it as necessary.

[0102] Examples of solvents for preparing the coating liquid for forming the undercoat layer include known organic solvents, such as alcohol-based solvents, aromatic hydrocarbon solvents, halogenated hydrocarbon solvents, ketone-based solvents, ketone alcohol-based solvents, ether-based solvents, and ester-based solvents. Specific examples of these solvents include ordinary organic solvents such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, and toluene.

[0103] Examples of a method for dispersing inorganic particles when preparing a coating liquid for forming an undercoat layer include known methods such as using a roll mill, a ball mill, a vibrating ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

[0104] Examples of a method for applying the coating liquid for forming the undercoat layer onto the conductive substrate include conventional methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0105] The thickness of the undercoat layer is set, for example, preferably at least 15 μm, more preferably in the range of from 20 μm to 50 μm.

[0106] [Middle layer] An intermediate layer may be further provided between the undercoat layer and the photosensitive layer. The intermediate layer is, for example, a layer containing a resin. Examples of the resin used in the intermediate layer include polymer compounds such as acetal resins (such as polyvinyl butyral), polyvinyl alcohol resins, polyvinyl acetal resins, casein resins, polyamide resins, cellulose resins, gelatin, polyurethane resins, polyester resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate-maleic anhydride resins, silicone resins, silicone-alkyd resins, phenol-formaldehyde resins, and melamine resins. The intermediate layer may be a layer containing an organometallic compound. Examples of the organometallic compound used in the intermediate layer include organometallic compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon. The compounds used in the intermediate layer may be used alone or as a mixture or polycondensation product of a plurality of compounds.

[0107] Among these, the intermediate layer is preferably a layer containing an organometallic compound containing zirconium atoms or silicon atoms.

[0108] The formation of the intermediate layer is not particularly limited, and a known formation method can be used. For example, the intermediate layer can be formed by forming a coating film of a coating liquid for forming an intermediate layer in which the above components are added to a solvent, drying the coating film, and heating it if necessary. The intermediate layer can be formed by any of the usual coating methods, such as dip coating, push-up coating, wire bar coating, spray coating, blade coating, air knife coating, and curtain coating.

[0109] The thickness of the intermediate layer is preferably set in the range of, for example, 0.1 μm to 3 μm, and the intermediate layer may also be used as an undercoat layer.

[0110] [Charge generation layer] The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. Alternatively, the charge generation layer may be a vapor-deposited layer of the charge generation material. A vapor-deposited layer of the charge generation material is suitable for use with an incoherent light source such as an LED (Light Emitting Diode) or an organic EL (Electroluminescence) image array.

[0111] Examples of the charge generating material include azo pigments such as bisazo and trisazo; fused-ring aromatic pigments such as dibromoanthanthrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

[0112] Among these, in order to be compatible with laser exposure in the near-infrared region, it is preferable to use a metal phthalocyanine pigment or a metal-free phthalocyanine pigment as the charge generating material, specifically, for example, hydroxygallium phthalocyanine, chlorogallium phthalocyanine, dichlorotin phthalocyanine, titanyl phthalocyanine, etc.

[0113] On the other hand, in order to accommodate laser exposure in the near ultraviolet region, preferred charge generating materials include fused ring aromatic pigments such as dibromoanthanthrone, thioindigo pigments, porphyrazine compounds, zinc oxide, trigonal selenium, and bisazo pigments.

[0114] The above charge generating material may also be used when an incoherent light source such as an LED or organic EL image array having a central emission wavelength of 450 nm or more and 780 nm or less is used.

[0115] In contrast, when n-type semiconductors such as fused-ring aromatic pigments, perylene pigments, and azo pigments are used as charge-generating materials, dark current is less likely to occur, and image defects known as black spots can be suppressed even in thin films. The n-type is determined by the polarity of the photocurrent that flows using the commonly used time-of-flight method, and materials that more easily pass electrons as carriers than holes are considered n-type.

[0116] The binder resin used in the charge generating layer may be selected from a wide range of insulating resins, and may also be selected from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. Examples of binder resins include polyvinyl butyral resin, polyarylate resin (e.g., polycondensation product of bisphenols and aromatic dicarboxylic acids), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyamide resin, acrylic resin, polyacrylamide resin, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinylpyrrolidone resin, etc. Here, "insulating" means a material having a volume resistivity of 1×10 13 This means that the resistance is Ω·cm or more. These binder resins may be used alone or in combination of two or more.

[0117] The compounding ratio of the charge generating material to the binder resin is preferably within the range of 10:1 to 1:10 by mass.

[0118] The charge generating layer may contain other known additives.

[0119] The formation of the charge generation layer is not particularly limited, and a known formation method can be used. For example, the charge generation layer can be formed by forming a coating film of a coating liquid for forming the charge generation layer by adding the above components to a solvent, drying the coating film, and heating it as necessary. The charge generation layer can also be formed by vapor deposition of the charge generation material. Formation of the charge generation layer by vapor deposition is particularly suitable when a fused ring aromatic pigment or a perylene pigment is used as the charge generation material.

[0120] Examples of solvents for preparing the coating liquid for forming the charge generating layer include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n-butyl acetate, dioxane, tetrahydrofuran, methylene chloride, chloroform, chlorobenzene, toluene, etc. These solvents may be used alone or in combination of two or more.

[0121] Methods for dispersing particles (e.g., charge generating material) in the coating liquid for forming the charge generating layer include, for example, media dispersers such as ball mills, vibration ball mills, attritors, sand mills, and horizontal sand mills, and medialess dispersers such as stirrers, ultrasonic dispersers, roll mills, and high-pressure homogenizers. Examples of high-pressure homogenizers include a collision method in which the dispersion liquid is dispersed by liquid-liquid collision or liquid-wall collision under high pressure, and a penetration method in which the dispersion liquid is dispersed by passing through a fine flow path under high pressure. During this dispersion, it is effective to adjust the average particle size of the charge generating material in the coating liquid for forming the charge generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less.

[0122] Examples of methods for applying the coating liquid for forming the charge generating layer onto the undercoat layer (or onto the intermediate layer) include conventional methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0123] The thickness of the charge generating layer is set, for example, preferably in the range of 0.1 μm to 5.0 μm, more preferably 0.2 μm to 2.0 μm.

[0124] [Charge transport layer] The charge transport layer is, for example, a layer containing a charge transport material and a binder resin, or may be a layer containing a polymer charge transport material.

[0125] Examples of charge transport materials include electron transport compounds such as quinone compounds such as p-benzoquinone, chloranil, bromanil, and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds; cyanovinyl compounds; and ethylene compounds. Examples of charge transport materials also include hole transport compounds such as triarylamine compounds, benzidine compounds, arylalkane compounds, aryl-substituted ethylene compounds, stilbene compounds, anthracene compounds, and hydrazone compounds. These charge transport materials may be used alone or in combination, but are not limited to these.

[0126] As the charge transport material, triarylamine derivatives represented by the following structural formula (a-1) and benzidine derivatives represented by the following structural formula (a-2) are preferred from the viewpoint of charge mobility.

[0127] [ka]

[0128] In structural formula (a-1), Ar T1 , Ar T2 , and Ar T3 each independently represents a substituted or unsubstituted aryl group, -C6H4-C(R T4 )=C(R T5 )(R T6 ), or -C6H4-CH=CH-CH=C(R T7 )(R T8 ) indicates R T4 , R T5 , R T6 , R T7 , and R T8 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituents on each of the above groups include halogen atoms, alkyl groups having from 1 to 5 carbon atoms, and alkoxy groups having from 1 to 5 carbon atoms. Examples of the substituents on each of the above groups also include substituted amino groups substituted with alkyl groups having from 1 to 3 carbon atoms.

[0129] [ka]

[0130] In structural formula (a-2), R T91 and R T92 R each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group having 1 to 5 carbon atoms. T101 , R T102 , R T111 and R T112 each independently represents a halogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an amino group substituted with an alkyl group having 1 to 2 carbon atoms, a substituted or unsubstituted aryl group, -C(R T12 )=C(R T13 )(R T14 ), or -CH=CH-CH=C(R T15 )(R T16 ) and R T12 , R T13 , R T14 , R T15 and R T16 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, ​​Tn1, and Tn2 each independently represent an integer of 0 or more and 2 or less. Examples of the substituents on each of the above groups include halogen atoms, alkyl groups having from 1 to 5 carbon atoms, and alkoxy groups having from 1 to 5 carbon atoms. Examples of the substituents on each of the above groups also include substituted amino groups substituted with alkyl groups having from 1 to 3 carbon atoms.

[0131] Among the triarylamine derivatives represented by the structural formula (a-1) and the benzidine derivatives represented by the structural formula (a-2), in particular, "-C6H4-CH=CH-CH=C(R T7 )(RT8 )" and triarylamine derivatives having "-CH=CH-CH=C(R T15 )(R T16 ) is preferred from the viewpoint of charge mobility.

[0132] As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester polymer charge transport materials are particularly preferred. The polymer charge transport material may be used alone or in combination with a binder resin.

[0133] Examples of binder resins used in the charge transport layer include polycarbonate resins, polyester resins, polyarylate resins, methacrylic resins, acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl acetate resins, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, silicone resins, silicone alkyd resins, phenol-formaldehyde resins, styrene-alkyd resins, poly-N-vinylcarbazole, and polysilanes. Among these, polycarbonate resins or polyarylate resins are preferred as binder resins. These binder resins may be used alone or in combination of two or more. The compounding ratio of the charge transport material to the binder resin is preferably from 10:1 to 1:5 by mass.

[0134] The charge transport layer may contain other known additives.

[0135] The charge transport layer can be formed by a known method, for example, by forming a coating film of a coating solution for forming the charge transport layer by adding materials to a solvent, drying the coating film, and heating it as needed to form the charge transport layer.

[0136] Examples of solvents for preparing the coating solution for forming the charge transport layer include organic solvents such as aromatic hydrocarbons such as benzene, toluene, xylene, and chlorobenzene; ketones such as acetone and 2-butanone; halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, and ethylene chloride; and cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents can be used alone or in combination of two or more.

[0137] Examples of the coating method for applying the coating liquid for forming the charge transport layer onto the charge generating layer include blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating.

[0138] The thickness of the charge transport layer is set, for example, preferably in the range of 5 μm to 50 μm, more preferably 10 μm to 30 μm.

[0139] [Single-layer photosensitive layer] The single-layer photosensitive layer is a layer containing, for example, a charge generating material, a charge transporting material, and optionally a binder resin and other additives. These materials are the same as those described for the charge generating layer and the charge transporting layer.

[0140] The content of the charge generating material in the single-layer photosensitive layer is preferably 0.1% by mass to 10% by mass, and more preferably 0.8% by mass to 5% by mass, based on the total solid content. The content of the charge transport material in the single-layer photosensitive layer is preferably 5% by mass or more and 50% by mass or less based on the total solid content.

[0141] The method for forming the single-layer photosensitive layer is the same as the method for forming the charge generating layer or the charge transport layer.

[0142] The thickness of the single-layer photosensitive layer is, for example, 5 μm or more and 50 μm or less, and preferably 10 μm or more and 40 μm or less.

[0143] [Cleaning blade] The cleaning blade may have a single layer structure or a laminated structure in which multiple layers are laminated together. The cleaning blade preferably has an elastic body as its base material.

[0144] The cleaning blade preferably has a base material made of polyurethane, and more preferably has a base material made of urethane rubber.

[0145] Polyurethanes are generally polymers of polyisocyanates and polyols. The polyurethane is preferably a urethane rubber, and the 100% modulus of the urethane rubber can be controlled by adjusting the content ratio of the hard segment to the soft segment contained in the urethane rubber.

[0146] Examples of polyisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-tolylene diisocyanate (2,6-TDI), 1,6-hexane diisocyanate (HDI), 1,5-naphthalene diisocyanate (NDI), and 3,3'-dimethylbiphenyl-4,4'-diisocyanate (TODI). Preferred polyisocyanates are MDI, NDI, and HDI.

[0147] Examples of the polyol include polyols contained in the soft segment material and hard segment material below.

[0148] As the soft segment material, polyether polyols are preferably used, such as polyethylene glycol, polyoxytetramethylene glycol, polyoxypropylene glycol, and polycaprolactone polyol. As the soft segment material, polyols other than polyether polyols may be used, such as polyester polyols obtained by dehydration condensation of diols and dibasic acids, and polycarbonate polyols obtained by reaction of diols and alkyl carbonates. The soft segment material may be used alone or in combination of two or more kinds.

[0149] A chain extender is preferably used as the hard segment material, and examples of the chain extender include polyols having a molecular weight of 300 or less, such as 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylene glycol, triethylene glycol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, and 1,2,6-hexanetriol. The hard segment material may be used alone or in combination of two or more.

[0150] The hard segment material may be a resin having a functional group capable of reacting with an isocyanate group. The resin is preferably a flexible resin, and from the viewpoint of flexibility, a linear aliphatic resin is preferable. Examples of the resin include an acrylic resin containing two or more hydroxyl groups, a polybutadiene resin containing two or more hydroxyl groups, and an epoxy resin containing two or more epoxy groups.

[0151] Urethane rubber can be produced by molding a composition obtained by mixing polyisocyanate, polyol (e.g., hard segment material and soft segment material), crosslinking agent, and catalyst. Examples of crosslinking agents include diols, triols, tetraols, etc. Examples of catalysts include tertiary amines, quaternary ammonium salts, and organotin compounds.

[0152] The cleaning blade has an impregnated and cured layer of an isocyanate compound and a silicone-modified acrylic polymer at least at the contact portion that comes into contact with the surface of the photoreceptor.

[0153] The impregnated and cured layer is a layer obtained by impregnating a cleaning blade substrate with an impregnation treatment liquid containing an isocyanate compound and a silicone-modified acrylic polymer and curing the liquid. In other words, the cleaning blade substrate is modified with the isocyanate compound and the silicone-modified acrylic polymer at least at the contact portion that contacts the surface of the photoreceptor.

[0154] Examples of the isocyanate compound include 4,4'-diphenylmethane diisocyanate (MDI), 2,6-tolylene diisocyanate (2,6-TDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), 3,3'-dimethylbiphenyl-4,4'-diisocyanate (TODI), and polymers and modified products thereof.

[0155] Silicone-modified acrylic polymers are resins in which silicone side chains are bonded to the main chain of a (meth)acrylic polymer. Examples of silicone-modified acrylic polymers include the Acrit 8BS series from Taisei Fine Chemical Co., Ltd.

[0156] The weight average molecular weight of the silicone-modified acrylic polymer is preferably from 10,000 to 100,000, more preferably from 20,000 to 80,000, and even more preferably from 40,000 to 60,000.

[0157] The impregnation treatment liquid contains an isocyanate compound, a silicone-modified acrylic polymer, and an organic solvent capable of dissolving or dispersing the isocyanate compound and the silicone-modified acrylic polymer. The organic solvent is preferably an organic solvent with excellent volatility, such as ethyl acetate.

[0158] The mass ratio of the isocyanate compound to the silicone-modified acrylic polymer contained in the impregnation treatment liquid is, for example, preferably isocyanate compound:silicone-modified acrylic polymer=100:40 to 100:10, more preferably 100:35 to 100:15, and even more preferably 100:30 to 100:20.

[0159] The impregnation hardened layer is formed by thoroughly drying the surface and the inside of the cleaning blade substrate after immersion in the impregnation treatment solution and then pulling it out.

[0160] [toner] The toner contains toner particles and an external additive externally added to the toner particles, and is obtained by adding the external additive to the toner particles.

[0161] [Toner particles] The toner particles are composed of, for example, a binder resin, a colorant, a release agent, and other additives.

[0162] -Binder resin- Examples of binder resins include homopolymers 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 (e.g., vinyl methyl ketone, vinyl ethyl ketone, vinyl isopropenyl ketone, etc.), and olefins (e.g., ethylene, propylene, butadiene, etc.), and vinyl resins made of copolymers of two or more of these monomers. Examples of the binder resin 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 vinyl resins, and graft polymers obtained by polymerizing vinyl monomers in the presence of these. These binder resins may be used alone or in combination of two or more.

[0163] As the binder resin, a polyester resin is preferable. Examples of polyester resins include known polyester resins.

[0164] The polyester resin may be, for example, a condensation polymer of a polycarboxylic acid and a polyhydric alcohol. As the polyester resin, a commercially available product or a synthesized product may be used.

[0165] Examples of polycarboxylic acids include aliphatic dicarboxylic acids (such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, alkenylsuccinic acid, adipic acid, and sebacic acid), alicyclic dicarboxylic acids (such as cyclohexanedicarboxylic acid), aromatic dicarboxylic acids (such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid), anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). Among these, aromatic dicarboxylic acids are preferred as polycarboxylic acids. As the polycarboxylic acid, a trivalent or higher carboxylic acid having a crosslinked or branched structure may be used in combination with a dicarboxylic acid. Examples of the trivalent or higher carboxylic acid include trimellitic acid, pyromellitic acid, anhydrides thereof, and lower alkyl esters thereof (e.g., having 1 to 5 carbon atoms). The polycarboxylic acids may be used alone or in combination of two or more.

[0166] 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, preferred polyhydric alcohols are aromatic diols and alicyclic diols, and more preferred are aromatic diols. As the polyhydric alcohol, a trihydric or higher polyhydric alcohol having a crosslinked or branched structure may be used in combination with the diol. Examples of trihydric or higher polyhydric alcohols include glycerin, trimethylolpropane, and pentaerythritol. The polyhydric alcohols may be used alone or in combination of two or more.

[0167] The glass transition temperature (Tg) of the polyester resin is preferably 50°C or higher and 80°C or lower, and more preferably 50°C or higher and 65°C or lower. The glass transition temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC), and more specifically, is determined from the "extrapolated glass transition onset temperature" described in the method for determining glass transition temperature in JIS K7121-1987 "Method for measuring transition temperature of plastics."

[0168] The weight average molecular weight (Mw) of the polyester resin is preferably 5,000 or more and 1,000,000 or less, and more preferably 7,000 or more and 500,000 or less. The number average molecular weight (Mn) of the polyester resin is preferably 2,000 or more and 100,000 or less. The molecular weight distribution Mw / Mn of the polyester resin is preferably 1.5 or more and 100 or less, and more preferably 2 or more and 60 or less. The weight average molecular weight and number average molecular weight are measured by gel permeation chromatography (GPC). Molecular weight measurements by GPC are performed using a Tosoh GPC HLC-8120GPC measuring device, a Tosoh TSKgel SuperHM-M (15 cm) column, and THF solvent. The weight average molecular weight and number average molecular weight are calculated from the measurement results using a molecular weight calibration curve prepared with monodisperse polystyrene standard samples.

[0169] The polyester resin can be obtained by a known production method, for example, by carrying out the reaction at a polymerization temperature of 180°C or higher and 230°C or lower, reducing the pressure in the reaction system as necessary, and removing water and alcohol generated during the condensation. If the raw material monomer is not soluble or compatible at the reaction temperature, a high-boiling solvent may be added as a solubilizer to dissolve it. In this case, the polycondensation reaction is carried out while distilling off the solubilizer. If a monomer with poor compatibility is present, it is advisable to first condense the poorly compatible monomer with the acid or alcohol to be polycondensed, and then polycondense it with the main component.

[0170] The content of the binder resin is preferably 40% by mass to 95% by mass, more preferably 50% by mass to 90% by mass, and even more preferably 60% by mass to 85% by mass, based on the total mass of the toner particles.

[0171] -Coloring agent- Examples of colorants include carbon black, chrome yellow, Hansa Yellow, benzidine yellow, threne 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, lithol red, rhodamine B lake, lake red C, pigment red, rose bengal, aniline blue, and ultramarine blue. pigments such as phthalocyanine blue, chalco oil blue, methylene blue chloride, phthalocyanine blue, pigment blue, phthalocyanine green, and malachite green oxalate; dyes such as acridine-based, xanthene-based, azo-based, benzoquinone-based, azine-based, anthraquinone-based, thioindigo-based, dioxazine-based, thiazine-based, azomethine-based, indigo-based, phthalocyanine-based, aniline black-based, polymethine-based, triphenylmethane-based, diphenylmethane-based, and thiazole-based; and inorganic pigments such as titanium compounds and silica.

[0172] The colorant is not limited to a substance that absorbs light in the visible light region, but may be, for example, a substance that absorbs light in the near-infrared region, or may be a fluorescent colorant. Examples of colorants that have absorption in the near-infrared region include aminium salt compounds, naphthalocyanine compounds, squarylium compounds, and croconium compounds. Examples of fluorescent colorants include the fluorescent colorants described in paragraph 0027 of JP 2021-127431 A.

[0173] The colorant may be a colorant having luster. Examples of the luster colorant include metal powders such as aluminum, brass, bronze, nickel, stainless steel, and zinc; mica coated with titanium oxide or yellow iron oxide; coated flaky inorganic crystal substrates such as barium sulfate, layered silicates, and layered aluminum silicates; single-crystal plate-like titanium oxide, basic carbonates, bismuth oxychloride, natural guanine, flaky glass powder, and metal-deposited flaky glass powder.

[0174] The colorant may be used alone or in combination of two or more kinds. The colorant may be surface-treated as needed, and may be used in combination with a dispersant.

[0175] The toner particles may contain a colorant or may not contain a colorant. The toner may be a toner that does not contain a colorant in the toner particles, that is, a so-called transparent toner.

[0176] When the toner particles contain a colorant, the content of the colorant is preferably from 1% by mass to 30% by mass, and more preferably from 3% by mass to 15% by mass, based on the total mass of the toner particles.

[0177] -Mold release agent- Examples of release agents include hydrocarbon waxes, natural waxes such as carnauba wax, rice wax, and candelilla wax, synthetic or mineral / petroleum waxes such as montan wax, and ester waxes such as fatty acid esters and montanic acid esters, but are not limited thereto.

[0178] The melting temperature of the release agent is preferably 50°C or higher and 110°C or lower, and more preferably 60°C or higher and 100°C or lower. The melting temperature is determined from a DSC curve obtained by differential scanning calorimetry (DSC) by using the "melting peak temperature" described in the method for determining the melting temperature in JIS K7121-1987 "Method for measuring transition temperatures of plastics."

[0179] The content of the release agent is preferably from 1% by mass to 20% by mass, and more preferably from 5% by mass to 15% by mass, based on the total mass of the toner particles.

[0180] -Other additives- Examples of other additives include known additives such as magnetic materials, charge control agents, inorganic powders, etc. These additives are contained in the toner particles as internal additives.

[0181] -Characteristics of toner particles, etc.- The toner particles may be toner particles having a single layer structure, or may be toner particles having a so-called core-shell structure composed of a core (core particle) and a coating layer (shell layer) that coats the core. The toner particles having a core-shell structure may be composed of, for example, a core composed of a binder resin and, if necessary, other additives such as a colorant and a release agent, and a coating layer composed of a binder resin.

[0182] The volume average particle size (D50v) of the toner particles is preferably 2 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less. The average particle size of toner particles is measured using a Coulter Multisizer II (Beckman Coulter) and an ISOTON-II (Beckman Coulter) electrolyte. 0.5 mg to 50 mg of the sample to be measured is added to 2 ml of a 5% by weight aqueous solution of a surfactant (preferably sodium alkylbenzene sulfonate), and this is added to 100 ml to 150 ml of electrolyte. The electrolyte containing the sample is dispersed in an ultrasonic disperser for 1 minute, and the particle size is measured using a Coulter Multisizer II with a 100 μm aperture in the range of 2 μm to 60 μm. A total of 50,000 particles are sampled. Based on the measured particle size distribution, a volume or number distribution is plotted from the smallest diameter side, and the particle size at 50% of the cumulative size is taken as the volume average particle size D50v or number average particle size D50p.

[0183] [External additives] Inorganic particles can be used as external additives. Examples of inorganic particles include SiO2, TiO2, Al2O3, SrTiO3, CuO, ZnO, SnO2, CeO2, Fe2O3, MgO, BaO, CaO, K2O, Na2O, ZrO2, CaO·SiO2, and K2O·(TiO2). n , Al2O3·2SiO2, CaCO3, MgCO3, BaSO4, MgSO4, etc.

[0184] The surfaces of the inorganic particles are preferably subjected to a hydrophobic treatment. The hydrophobic treatment is carried out, for example, by immersing the inorganic particles in a hydrophobic treatment agent. Examples of the hydrophobic treatment agent include silane coupling agents, silicone oils, titanate coupling agents, and aluminum coupling agents. These may be used alone or in combination of two or more. The amount of the hydrophobic treatment agent is, for example, 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the inorganic particles.

[0185] Examples of external additives include resin particles such as polystyrene, polymethyl methacrylate, and melamine resin; cleaning agents such as higher fatty acid metal salt particles typified by zinc stearate, and fluorine-based polymer particles.

[0186] The amount of the external additive added is, for example, preferably 0.01% by mass to 10% by mass, more preferably 0.01% by mass to 6.0% by mass, based on the mass of the toner particles.

[0187] [Developer] The developer may be a one-component developer containing only toner, or a two-component developer containing a mixture of toner and carrier.

[0188] The carrier is not particularly limited, and known carriers can be used. Examples of the carrier include a coated carrier in which the surface of a core material made of magnetic powder is coated with a resin; a magnetic powder dispersion type carrier in which magnetic powder is dispersed and mixed in a matrix resin; and a resin impregnated type carrier in which porous magnetic powder is impregnated with a resin. A carrier in which a magnetic powder dispersion type carrier or a resin impregnated type carrier is used as a core material and the surface of this is coated with a resin may also be used.

[0189] Examples of magnetic powder include magnetic metals such as iron, nickel, and cobalt; and magnetic oxides such as ferrite and magnetite.

[0190] 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 resins containing organosiloxane bonds or modified products thereof, fluororesin, polyester, polycarbonate, phenolic resin, and epoxy resin. The coating resin and matrix resin may contain other additives such as conductive particles. Examples of conductive particles include particles of metals such as gold, silver, and copper, carbon black, titanium oxide, zinc oxide, tin oxide, barium sulfate, aluminum borate, and potassium titanate.

[0191] Examples of methods for coating the surface of the core material with a resin include a method using a coating layer-forming solution in which the coating resin and various additives (used as needed) are dissolved in an appropriate solvent. The solvent is not particularly limited and may be selected taking into consideration the type of resin used, its suitability for application, etc. Specific resin coating methods include an immersion method in which the core material is immersed in a solution for forming a coating layer; a spray method in which the solution for forming a coating layer is sprayed onto the surface of the core material; a fluidized bed method in which the solution for forming a coating layer is sprayed onto the core material while it is suspended in flowing air; and a kneader coater method in which the core material of the carrier and the solution for forming a coating layer are mixed in a kneader coater and then the solvent is removed.

[0192] The mixing ratio (mass ratio) of the toner and the carrier in the two-component developer is preferably toner:carrier=1:100 to 30:100, and more preferably 3:100 to 20:100. [Example]

[0193] The present embodiment will be described in detail below with reference to examples, but the present embodiment is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass. In the following description, synthesis, processing, manufacturing, testing, etc. were carried out at room temperature (25°C ± 3°C) unless otherwise specified.

[0194] <Photoreceptor manufacturing> [Photoconductor (1)] - Formation of undercoat layer - 100 parts of zinc oxide (average primary particle diameter 70 nm, Teika Corporation) was mixed with 500 parts of toluene and stirred, and 1.5 parts of a silane coupling agent (trade name: KBM603, Shin-Etsu Chemical Co., Ltd.) was added and stirred for 2 hours. Next, the toluene was distilled off under reduced pressure, and the mixture was baked at 150°C for 2 hours.

[0195] A liquid to be treated was obtained by mixing 25 parts of methyl ethyl ketone with 38 parts of a liquid composition prepared by dispersing and dissolving 60 parts of surface-treated zinc oxide, 15 parts of a curing agent (blocked isocyanate, product name: Sumidur BL3175, Sumitomo Bayer Urethane Co., Ltd.), and 15 parts of a butyral resin (product name: BM-1, Sekisui Chemical Co., Ltd.) in 85 parts of methyl ethyl ketone.

[0196] Glass beads (Hi-Bee D20, Ohara Corporation) with a diameter of 1 mm were added to the cylinder of a horizontal media mill disperser (KDL-PILOT type, Dyno Mill, Shinmaru Enterprises Co., Ltd.) at a bulk filling rate of 80% by volume. Dispersion was performed using a circulation system with the peripheral speed of the disperser's stirring mill set to 8 m / min and the flow rate of the treated liquid set to 1000 mL / min. A magnetic gear pump was used to transport the treated liquid to the disperser.

[0197] To the dispersion obtained by the above treatment, 0.005 parts of dioctyltin dilaurate as a catalyst and 0.01 parts of silicone oil (product name: SH29PA, Toray Dow Corning Silicones Co., Ltd.) were added to prepare a coating solution for an undercoat layer. The coating solution for the undercoat layer was applied to an aluminum substrate with a diameter of 84 mm, length of 340 mm, and thickness of 1 mm by dip coating, and then dried and cured at 160°C for 100 minutes to form an undercoat layer with a thickness of 20 μm.

[0198] - Formation of charge generation layer - A mixture of 15 parts of chlorogallium phthalocyanine (having diffraction peaks at Bragg angles (2θ±0.2°) of at least 7.4°, 16.6°, 25.5°, and 28.3° in an X-ray diffraction spectrum using CuKα radiation), 10 parts of vinyl chloride-vinyl acetate copolymer resin (trade name: VMCH, Nippon Unicar Co., Ltd.), and 300 parts of n-butyl alcohol was dispersed in a sand mill using 1 mm diameter glass beads for 4 hours to obtain a charge generation layer coating solution. The charge generation layer coating solution was dip-coated onto the undercoat layer and dried to form a charge generation layer with a thickness of 0.2 μm.

[0199] - Formation of charge transport layer - A coating solution for a charge transport layer was prepared by dissolving 4 parts of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-[1,1']biphenyl-4,4'-diamine and 6 parts of bisphenol Z polycarbonate resin (viscosity average molecular weight: 40,000) in 80 parts of chlorobenzene. The coating solution for a charge transport layer was applied onto the charge generation layer and dried at 130°C for 40 minutes to form a charge transport layer with a thickness of 25 μm.

[0200] - Formation of inorganic surface layer (gallium oxide layer) - The photoconductor with the charge transport layer formed was introduced into the plasma CVD device, and the pressure in the vacuum chamber was reduced to 1×10 -2 The chamber was evacuated to a vacuum of 10 Pa. Hydrogen gas, He-diluted oxygen (oxygen concentration: 4%), and hydrogen-diluted trimethylgallium (trimethylgallium concentration: approximately 10%) were supplied to the vacuum chamber from the gas supply pipe via a mass flow controller. The flow rates were hydrogen gas: 200 sccm, He-diluted oxygen: 5 sccm, and hydrogen-diluted trimethylgallium: 5 sccm. The pressure inside the vacuum chamber was set to 10 Pa by adjusting the conductance valve while supplying the gases, and discharge was performed from the discharge electrode. A gallium oxide layer was formed on the charge transport layer while the photoreceptor was rotated at a speed of 20 rpm.

[0201] [Photoreceptor (2)] An aluminum oxide layer was formed on the charge transport layer in the same manner as in the production of photoreceptor (1), except that trimethylaluminum was used instead of trimethylgallium in the formation of the inorganic surface layer.

[0202] [Photoconductor (3)] The photoreceptor (1) before the formation of the inorganic surface layer was designated as the photoreceptor (3). That is, the surface layer of the photoreceptor (3) is a charge transport layer.

[0203] <Cleaning blade manufacturing> [Cleaning blade (1)] -Preparation of substrate- 100 parts of polycaprolactone polyol (molecular weight 2000) and 57 parts of 4,4'-diphenylmethane diisocyanate (MDI, DIC Corporation) were reacted at 115°C for 20 minutes. Next, 6 parts of 1,4-butanediol and 2.5 parts of trimethylolpropane were mixed. The mixture was placed in a mold maintained at 140°C and heat-cured for 40 minutes to obtain a urethane rubber. The urethane rubber was cut into a length of 330 mm, a width of 13.5 mm, and a thickness of 1.9 mm to obtain a urethane rubber sheet. Two urethane rubber sheets were bonded together with adhesive to obtain the base material for the cleaning blade. One end of the base material was laser processed so that the tip angle of the contact point that comes into contact with the surface of the photoreceptor is 80 degrees.

[0204] -Preparation of impregnation solution- 25 parts of 4,4'-diphenylmethane diisocyanate (MDI, Tosoh Corporation "Millionate MT"), 5 parts of silicone-modified acrylic polymer (8BS-9000, Taisei Fine Chemical Co., Ltd.), and 80 parts of ethyl acetate were mixed in a ball mill for 5 hours to obtain an impregnation treatment solution.

[0205] - Formation of impregnated hardened layer - The temperature of the impregnation treatment liquid was adjusted to 23°C, and the substrate was immersed in the impregnation treatment liquid for 60 seconds while maintaining the temperature at 23°C. It was then dried at room temperature for 1 minute, and the blade surface was wiped with a sponge containing a small amount of toluene. It was then dried at room temperature for 1 minute and placed in a thermostatic bath at 25°C for 50 minutes to form a cured impregnation layer.

[0206] [Cleaning blades (2) to (6)] Cleaning blades (2) to (6) were produced in the same manner as cleaning blade (1), except that the amount of MDI used in producing the substrate was changed as shown in Table 1.

[0207] [Cleaning blade (7)] The base material of the cleaning blade (1) was replaced with the cleaning blade (7), which is a cleaning blade that does not have an impregnated hardened layer.

[0208] [Cleaning blades (8) to (13)] Cleaning blades (8) to (13) were manufactured in the same manner as cleaning blade (1), except that the tip angle was changed as shown in Table 1.

[0209] <Manufacturing of image forming devices> [Examples 1 to 12, Comparative Examples 1 to 8] One of the photoreceptors (1) to (3) and one of the cleaning blades (1) to (13) were mounted in an image forming apparatus Apeos C8180 (Fujifilm Business Innovation Co., Ltd.) in the combination shown in Table 1. The operating angle of the cleaning blade relative to the surface of the photoreceptor was adjusted to the angle shown in Table 1. The developing units for each color were filled with developers containing toners with silica particles externally added to the respective colors.

[0210] <Performance evaluation> Using the above image forming apparatus, 50,000 images with an image density of 7% were printed on A4 plain paper in a low-temperature, low-humidity environment of 10°C and 15% relative humidity. After printing, the photoreceptor and cleaning blade were evaluated using the following evaluation methods. The evaluation results are shown in Table 1. In a low-temperature, low-humidity environment, urethane rubber becomes relatively hard, and external additive dams are less likely to form at the contact point with the cleaning blade, making it easier for external additives to slip through the cleaning blade.

[0211] [Photoreceptor wear] The layer thickness of the photoreceptor was measured before and after image formation using an eddy current film thickness meter. The difference between the thicknesses before and after image formation, i.e., the amount of wear, was calculated and classified as follows: A: 0.6μm or less B: More than 0.6μm, less than 0.8μm C: More than 0.8μm, less than 1.2μm D: More than 1.2μm, less than 1.6μm E: More than 1.6μm

[0212] [Cleaning blade wear] The shape of the cleaning blade tip was observed with a laser microscope (Keyence Corporation, VK-9500). The difference, i.e., the amount of wear, was calculated by comparing with the designed shape, and the amount of wear was classified as follows: A: 1.7 μm 2 below B: 1.7 μm 2 Ultra, 2.0μm 2 below C: 2.0 μm 2 Ultra, 2.3μm 2 below D: 2.3 μm 2 Ultra, 3.0μm 2 below E: 3.0 μm 2 super

[0213] [Photoreceptor filming] The surface of the photoreceptor was observed with a laser microscope (Keyence Corporation, VK-9500). The filming coverage was classified as follows: A: No filming occurred. B: Slight filming occurs, at a level that is fully acceptable for practical use. C: Filming occurs, but is at an acceptable level for practical use. D: Filming occurred. Unacceptable level for practical use. E: Filming occurs frequently. Unacceptable level for practical use.

[0214] [Table 1]

[0215] The image forming apparatus of the present disclosure includes the following aspects.

[0216] (Addendum) (((1))) A photoreceptor; a charging device that charges the surface of the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoreceptor; a developing device that contains a developer containing toner and develops the electrostatic latent image formed on the surface of the photoreceptor to form a toner image; a transfer device that transfers the toner image onto a surface of a recording medium; a cleaning device having a cleaning blade that comes into contact with the surface of the photoreceptor and cleans the surface of the photoreceptor; the photoreceptor has an inorganic surface layer containing a Group 13 element and an oxygen element, the cleaning blade has an impregnated and cured layer of an isocyanate compound and a silicone-modified acrylic polymer at a contact portion that comes into contact with the surface of the photoreceptor, the 100% modulus of the cleaning blade is 13 MPa or more and 22 MPa or less, The tip angle of the cleaning blade is 60 degrees or more and 87 degrees or less, the operating angle of the cleaning blade relative to the surface of the photoreceptor is 8 degrees or more and 30 degrees or less; Image forming device. (((2))) The image forming apparatus according to (((1))), wherein the coefficient of dynamic friction between the surface of the photosensitive member and the contact portion of the cleaning blade is 0.3 or more and 0.6 or less. (((3))) The image forming apparatus according to (((1))) or (((2))), wherein the 100% modulus of the cleaning blade is 13 MPa or more and 18 MPa or less. (((4))) The image forming apparatus according to any one of (((1))) to (((3))), wherein the tip angle of the cleaning blade is 80 degrees or more and 85 degrees or less. (((5))) The image forming apparatus according to any one of (((1))) to (((4))), wherein the inorganic surface layer of the photoreceptor is a layer containing an oxide of a Group 13 element. (((6))) The image forming apparatus according to any one of (((1))) to (((5))), wherein the inorganic surface layer of the photoreceptor is a gallium oxide layer. (((7))) The image forming apparatus according to any one of (((1))) to (((6))), wherein the base material of the cleaning blade is polyurethane.

[0217] According to (((1))), (((5))), (((6))) or (((7))), an image forming apparatus is provided which is superior in abrasion resistance of the photoreceptor and abrasion resistance of the cleaning blade compared to an image forming apparatus equipped with a photoreceptor which does not have an inorganic surface layer and / or a cleaning blade which does not have an impregnated cured layer, and an image forming apparatus is provided which is less likely to produce filming on the surface of the photoreceptor compared to an image forming apparatus in which the 100% modulus of the cleaning blade is less than 13 MPa or more than 22 MPa, or the tip angle of the cleaning blade is less than 60 degrees or more than 87 degrees, or the working angle of the cleaning blade with respect to the surface of the photoreceptor is less than 8 degrees or more than 30 degrees. According to (((2))), an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the coefficient of dynamic friction between the surface of the photoreceptor and the contact portion of the cleaning blade is less than 0.3, and an image forming apparatus is provided in which the wear resistance of the photoreceptor and the wear resistance of the cleaning blade are superior to those in an image forming apparatus in which the coefficient of dynamic friction between the surface of the photoreceptor and the contact portion of the cleaning blade is greater than 0.6. According to (((3))), an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the 100% modulus of the cleaning blade is less than 13 MPa or more than 18 MPa. According to (((4))), an image forming apparatus is provided in which filming is less likely to occur on the surface of the photoreceptor than in an image forming apparatus in which the tip angle of the cleaning blade is less than 80 degrees or more than 85 degrees. [Explanation of symbols]

[0218] 30 cleaning blade, 31E corner portion, 70 support member, 7 photosensitive member

[0219] 7 photosensitive member, 8 charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 40 transfer device, 50 intermediate transfer body, 100 image forming apparatus, 120 image forming apparatus, 131 cleaning blade, 132 fibrous member (roll-shaped), 133 fibrous member (flat brush-shaped), 300 process cartridge

[0220] 1 Conductive substrate, 2 Undercoat layer, 3 Charge generation layer, 4 Charge transport layer, 5 Photosensitive layer, 6 Inorganic surface layer, 10A photoreceptor, 10B photoreceptor

Claims

1. A photoreceptor; a charging device that charges the surface of the photoreceptor; an electrostatic latent image forming device for forming an electrostatic latent image on the charged surface of the photoreceptor; a developing device that contains a developer containing toner and develops the electrostatic latent image formed on the surface of the photoreceptor to form a toner image; a transfer device that transfers the toner image onto a surface of a recording medium; a cleaning device having a cleaning blade that comes into contact with the surface of the photoreceptor and cleans the surface of the photoreceptor; the photoreceptor has an inorganic surface layer containing a Group 13 element and an oxygen element, the cleaning blade has an impregnated and cured layer of an isocyanate compound and a silicone-modified acrylic polymer at a contact portion that comes into contact with the surface of the photoreceptor, the 100% modulus of the cleaning blade is 13 MPa or more and 22 MPa or less; the tip angle of the cleaning blade is 60 degrees or more and 87 degrees or less; the operating angle of the cleaning blade relative to the surface of the photoreceptor is 8 degrees or more and 30 degrees or less; Image forming device.

2. 2. The image forming apparatus according to claim 1, wherein a coefficient of dynamic friction between the surface of the photosensitive member and the contact portion of the cleaning blade is 0.3 or more and 0.6 or less.

3. 2. The image forming apparatus according to claim 1, wherein the 100% modulus of the cleaning blade is 13 MPa or more and 18 MPa or less.

4. 2. The image forming apparatus according to claim 1, wherein the tip angle of the cleaning blade is between 80 degrees and 85 degrees.

5. 2. The image forming apparatus according to claim 1, wherein the inorganic surface layer of the photoreceptor is a layer containing an oxide of a Group 13 element.

6. 2. The image forming apparatus according to claim 1, wherein the inorganic surface layer of the photoreceptor is a gallium oxide layer.

7. 2. The image forming apparatus according to claim 1, wherein the base material of the cleaning blade is polyurethane.

Images