Electrophotographic photosensitive member, process cartridge, and electrophotographic apparatus

Abstract

The present invention relates to an electrophotographic photosensitive member, a process cartridge, and an electrophotographic apparatus. Provided is an electrophotographic photosensitive member including, in this order, a support, a photosensitive layer, and a surface layer, wherein an outer surface of the electrophotographic photosensitive member exhibits a corrugated shape by having a concave-convex shape, the surface layer contains a binder resin and inorganic particles, and at least a part of the inorganic particles is exposed at a concave portion of the concave-convex shape.

Description

Technical Field

[0001] The present invention relates to an electrophotographic photosensitive element, as well as a processing box and an electrophotographic apparatus, each including the electrophotographic photosensitive element. Background Technology

[0002] Organic electrophotographic photosensitive elements (hereinafter referred to as "electrophotographic photosensitive elements" or "photosensitive elements") containing organic photoconductive materials (charge-generating materials) have been used as electrophotographic photosensitive elements installed in processing cartridges or electrophotographic devices. Recently, there has been a need for electrophotographic devices with longer lifespans. Therefore, it is desirable to provide electrophotographic photosensitive elements with improved image quality and improved wear resistance (mechanical durability).

[0003] In addition to the aforementioned measures aimed at extending lifespan, there has been a recent need for electrophotographic equipment to improve the efficiency of the transfer process, in order to improve image quality by suppressing toner scattering during transfer and to reduce the amount of waste toner.

[0004] As a measure to improve the wear resistance of electrophotographic photosensitive components, a technique is proposed to increase the mechanical strength of the surface layer of the photosensitive component by using a free radical polymerizable resin in the surface layer to prepare the surface layer as a cured layer.

[0005] Electrophotographic photosensitive components are typically used in the electrophotographic image formation process, which includes charging, exposure, development, transfer, and cleaning processes. Among these, the cleaning process, which removes residual toner from the electrophotographic photosensitive component after the transfer process, is crucial for obtaining a clear image. A common cleaning method involves pressing a rubber-like cleaning blade against the electrophotographic photosensitive component to scrape off the toner.

[0006] However, in the above-described cleaning method, due to the high friction between the cleaning blade and the electrophotographic photosensitive component, blade vibration occurs, and image defects caused by poor cleaning are prone to occur. This problem becomes more pronounced in the cleaning process as the mechanical strength of the surface layer of the electrophotographic photosensitive component increases—that is, the circumferential surface of the electrophotographic photosensitive component is less likely to be worn. In other words, this problem becomes more likely to occur when the surface layer of the electrophotographic photosensitive component is prepared as a cured layer to increase its mechanical strength, as described above.

[0007] Furthermore, the surface layer of organic electrophotographic photosensitive components is often formed by dip coating in many cases, and the surface of the surface layer formed by dip coating (i.e., the outer surface of the electrophotographic photosensitive component) becomes very smooth. As a result, the contact area between the cleaning blade and the circumferential surface of the electrophotographic photosensitive component increases, and the wear resistance between the cleaning blade and the circumferential surface of the electrophotographic photosensitive component improves, and the aforementioned problems become significant.

[0008] As a measure to overcome the above problems, the following method is proposed, wherein a concave-convex shape is provided on the outer surface of the electrophotographic photosensitive component to reduce the contact area between the outer surface of the photosensitive component and the cleaning squeegee, thereby reducing friction and improving cleaning performance.

[0009] Japanese Patent Application Publication No. 2018-128515 discloses a technique using a surface layer containing fine metal oxide particles. It is argued that when the surface layer contains fine metal oxide particles, some of these particles protrude from the outer surface of the electrophotographic photosensitive element to form an uneven shape, thereby reducing the friction between the cleaning blade and the photosensitive element.

[0010] Furthermore, Japanese Patent Application Publication No. 2010-250355 discloses a technique concerning a photosensitive member having a groove shape along the circumferential direction of the circumferential surface of the photosensitive member. In the technique described in Japanese Patent Application Publication No. 2010-250355, by providing a groove shape along the circumferential direction on the outer surface of the photosensitive member, the contact area between the cleaning blade and the photosensitive member is reduced, thereby reducing friction.

[0011] The technology described in Japanese Patent Application Publication No. 2018-128515 does not sufficiently reduce the friction between the cleaning blade and the photosensitive element, and the torque may increase when used in low temperature and low humidity environments.

[0012] Furthermore, in the technology described in Japanese Patent Application Publication No. 2010-250355, poor cleaning may occur in low-temperature and low-humidity environments, where the toner partially slides across the groove-shaped portion. Moreover, in the technology described in Japanese Patent Application Publication No. 2010-250355, there is room for improvement in transferability. Summary of the Invention

[0013] The present invention was made in view of the above-mentioned problems. That is, the object of the present invention is to provide an electrophotographic photosensitive component that can reduce friction with the cleaning blade, exhibit high cleaning performance and excellent transferability when used in low temperature and low humidity environments.

[0014] The above-mentioned objective is achieved by the present invention described below. Specifically, the electrophotographic photosensitive component according to the present invention comprises, in sequence, a support, a photosensitive layer, and a surface layer. The outer surface of the electrophotographic photosensitive component exhibits a wrinkled shape by having an uneven shape. When a square observation area with a side length of 200 μm is provided at any position on the outer surface, a line passing through the center point of the observation area and parallel to the circumferential direction of the electrophotographic photosensitive component is defined as a reference line L1. Furthermore, 1,799 reference lines obtained by rotating the reference line L1 around the center point at 0.1° intervals are defined as reference lines L2 to L1,800, respectively. Reference lines L1 to L1,800 intersect the ridge of the uneven shape at multiple positions, and the angle of intersection between each reference line L1 to L1,800 and the ridge has different values ​​at at least two of the selected positions. The surface layer comprises an adhesive resin and inorganic particles, and at least a portion of the inorganic particles are exposed in the recesses of the uneven shape.

[0015] Further features of the invention will become apparent from the following description of exemplary embodiments, with reference to the accompanying drawings. Attached Figure Description

[0016] Figure 1A A top view illustrating an example of the uneven shape of the outer surface of the electrophotographic photosensitive component according to the present invention.

[0017] Figure 1B This is an example of a diagram showing height information obtained by observing the outer surface of the electrophotographic photosensitive component according to the present invention.

[0018] Figure 2A A diagram showing the two-dimensional power spectrum F(r,θ) obtained by analyzing the frequency of wrinkles on the outer surface of the electrophotographic photosensitive element according to the invention.

[0019] Figure 2B To illustrate a graph of a one-dimensional radial distribution function obtained by integrating a two-dimensional power spectrum F(r,θ) along the θ direction, the two-dimensional power spectrum F(r,θ) is obtained by analyzing the frequency of wrinkles on the outer surface of the electrophotographic photosensitive element according to the invention.

[0020] Figure 2C For when Figure 2B The figure shows the variation of power values ​​over the entire θ range when the angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at the frequency rp where the one-dimensional radial distribution function p(r) has a maximum value.

[0021] Figure 3 This is a schematic diagram showing a cross-section of the outer surface of an electrophotographic photosensitive component.

[0022] Figure 4 This is a schematic diagram illustrating the exposure of inorganic particles when viewed from above on the outer surface of an electrophotographic photosensitive component.

[0023] Figure 5 This diagram illustrates a schematic configuration of an electrophotographic device, including a processing box in which an electrophotographic photosensitive element is disposed.

[0024] Figure 6 A diagram showing a polishing machine used for polishing the outer surface of an electrophotographic photosensitive component according to a comparative example. Detailed Implementation

[0025] Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings.

[0026] It is believed that the technology described in Japanese Patent Application Publication No. 2018-128515 cannot sufficiently reduce the contact area between the photosensitive component and the cleaning blade, resulting in the following situation: the friction is not sufficiently reduced when used in low temperature and low humidity environments.

[0027] Furthermore, toners and photosensitive components are prone to becoming charged in low-temperature and low-humidity environments, thus increasing the electrostatic adhesion between the toner and the photosensitive component. In the technology described in Japanese Patent Application Publication No. 2010-250355, the extension direction of the groove shape is parallel to the rotation direction of the photosensitive component. Therefore, as a result of research conducted by the inventors, it has been found that, particularly in low-humidity and low-temperature environments, residual toner on the outer surface of the photosensitive component slides across the contact portion between the photosensitive component and the cleaning blade via the groove shape, resulting in striped image defects. In particular, in recent years, to meet the requirements for high-resolution and high-quality images, spherical toners with small particle sizes have become mainstream. Spherical toners with small particle sizes have high adhesion to the outer surface of the photosensitive component, making it easy for the toner to be insufficiently removed using a cleaning blade. Consequently, when using spherical toners with small particle sizes, the technology described in Japanese Patent Application Publication No. 2010-250355 is considered to be more prone to causing striped image defects.

[0028] Furthermore, in low humidity and low temperature environments, as mentioned above, the adhesion between the toner and the photosensitive component tends to increase, thus the amount of residual toner on the outer surface of the photosensitive component tends to increase. To improve transferability, it is necessary to reduce the adhesion between the toner and the electrophotographic photosensitive component, and reducing the contact area between the toner and the electrophotographic photosensitive component is effective. Therefore, it is considered to reduce the contact area between the toner and the electrophotographic photosensitive component by providing an uneven shape on the outer surface of the photosensitive component. However, it has been found that the uneven shape disclosed in Japanese Patent Application Publication No. 2010-250355 is insufficient to improve transferability.

[0029] As a result of in-depth research, the inventors discovered that the above-mentioned problem can be solved by setting a predetermined concave-convex shape as described below and further by exposing the inorganic particles in the concave portion of the concave-convex shape.

[0030] Specifically, the electrophotographic photosensitive component according to the present invention comprises a support, a photosensitive layer, and a surface layer in sequence. The outer surface of the electrophotographic photosensitive component exhibits a wrinkled shape by having an uneven shape. When a square observation area with a side length of 200 μm is set at any position on the outer surface, a line passing through the center point of the observation area and parallel to the circumferential direction of the electrophotographic photosensitive component is defined as a reference line L1. 1,799 reference lines obtained by rotating the reference line L1 around the center point at 0.1° intervals are defined as reference lines L2 to L1,800, respectively. Each of the reference lines L1 to L1,800 intersects the ridge of the uneven shape at multiple positions, and the angle of intersection between each of the reference lines L1 to L1,800 and the ridge has a different value at at least two of the multiple positions. The surface layer comprises an adhesive resin and inorganic particles, and at least a portion of the inorganic particles are exposed in the recesses of the uneven shape.

[0031] Regarding the mechanism by which the electrophotographic photosensitive element according to the present invention, having the above-described configuration, solves the problems in the prior art as described above, although not explained, the inventors speculate as follows.

[0032] First, by using an electrophotographic photosensitive element with a predetermined number or more protrusions on its outer surface within a certain area, the contact area when the cleaning blade contacts the electrophotographic photosensitive element is sufficiently reduced. Therefore, it is presumed that even in low humidity and low temperature environments, the friction between the cleaning blade and the electrophotographic photosensitive element is sufficiently reduced. Furthermore, the outer surface of the electrophotographic photosensitive element exhibits a corrugated shape due to its uneven shape, and the ridges of the protrusions extend in various directions; therefore, it is believed that the toner's slippage through the concave parts of the uneven shape is also suppressed when the electrophotographic photosensitive element rotates. It is believed that, as a result of the above, both reducing friction and suppressing toner slippage can be achieved at a high level simultaneously.

[0033] Next, the reason why the electrophotographic photosensitive element according to the present invention has excellent transferability will be explained. According to research conducted by the inventors, when the outer surface of the electrophotographic photosensitive element only has the aforementioned uneven portion and no inorganic particles are exposed in the uneven recesses, the effect of improving transferability is limited. This is believed to be because the toner is pressed into the uneven recesses, and the adhesion between the toner and the surface of the photosensitive element becomes stronger. Then, as a result of further research, the inventors discovered that when the surface layer of the photosensitive element contains inorganic particles and these inorganic particles are exposed in the uneven recesses, excellent transferability can be obtained. This is presumably because the inorganic particles exposed in the uneven recesses make point contact with the toner, creating a gap between the toner and the surface of the photosensitive element by separating them by a distance, thus reducing the adhesion between the toner and the surface of the photosensitive element.

[0034] The following describes in more detail the uneven shape of the outer surface of the electrophotographic photosensitive element according to the invention and the inorganic particles contained in the surface layer of the electrophotographic photosensitive element according to the invention.

[0035] The uneven shape on the outer surface of the electrophotographic photosensitive component according to the present invention has a certain degree of fineness and has a certain number of protrusions in a certain area. Specifically, firstly, on the outer surface of the electrophotographic photosensitive component, an observation area is provided, each having a square shape with a side length of 200 μm and including 76 intersection points of 19 line segments dividing the electrophotographic photosensitive component into 20 equal parts along its axial direction as their respective center points and 4 line segments dividing the photosensitive component into 4 equal parts along its circumferential direction, such that one side of the square observation area is parallel to the circumferential direction of the photosensitive component. Then, for each observation area, a line passing through the center point of the observation area and parallel to the circumferential direction of the electrophotographic photosensitive component is defined as a reference line L1. Furthermore, 1,799 reference lines obtained by rotating the reference line L1 around the center point at 0.1° per unit distance are defined as reference lines L2 to L1,800. In this case, the uneven shape in each observation area includes a sufficient number of protrusions to intersect with the reference lines L1 to L1,800 at multiple locations.

[0036] Furthermore, the uneven shape on the outer surface of the electrophotographic photosensitive member according to the invention has a complex shape, and the ridges of the protrusions extend in various directions. Specifically, for each of the reference lines L1 to L1,800, at least two locations selected from a plurality of locations where the reference line intersects with the protrusion of the uneven shape have different intersection angles. Therefore, the outer surface of the electrophotographic photosensitive member according to the invention exhibits a wrinkled shape.

[0037] Figure 1A and Figure 1B A figure illustrating an example of the uneven shape of the outer surface of the electrophotographic photosensitive component according to the present invention. Figure 1A This is a top view of the outer surface of an electrophotographic photosensitive component, and Figure 1B This is a diagram showing height information obtained by observing the outer surface of an electrophotographic photosensitive component.

[0038] like Figure 1A As shown, the uneven shape on the outer surface of the electrophotographic photosensitive element according to the present invention has a striped uneven shape that can be observed on the outer surface of the electrophotographic photosensitive element. The striped shape is not distributed along a single direction, but is composed of curved portions, straight portions, discontinuous portions and branched portions, and multiple striped shapes exist in a square observation area with a side length of 200 μm.

[0039] In addition, such as by Figure 1A As shown by reference numeral a in the attached figure, the ridge line of the convex part of the concave-convex shape refers to the straight line or curve obtained by connecting the highest points of the convex parts that separate adjacent concave parts in the striped concave-convex shape when the outer surface of the electrophotographic photosensitive component is viewed from above.

[0040] There are no particular limitations on the method of determining protrusions to obtain ridges by observing the outer surface of an electrophotographic photosensitive component. However, ridges can be determined, for example, by image analysis using height information obtained from measuring the outer surface of the electrophotographic photosensitive component using a confocal laser scanning microscope. An example of plotting the height information obtained by this method at the position on a straight line set on the outer surface of the electrophotographic photosensitive component is... Figure 1B As shown in the image. Figure 1A The edge of the curve shown by reference numeral a in the attached figure can be determined by... Figure 1B The vertices of the convex shape shown by reference numeral b in the attached figure are used to obtain the shape.

[0041] Furthermore, in this invention, the ridge of the convex portion of the concave-convex shape has multiple curvatures within the ridge. Curvature is a quantity representing the degree of curvature of the curve, and when any point on the curve is approximated by a circle, the curvature χ is obtained as the reciprocal of the radius R of the circle, as shown in equation (I).

[0042]

[0043] Where s represents the length of the arc portion corresponding to the curve, and r is the position vector of any point on the curve.

[0044] Preferably, the electrophotographic photosensitive component according to the present invention satisfies the following conditions. That is, when a two-dimensional power spectrum F(r,θ) with frequency component r and angle component θ is obtained by performing frequency analysis of the height information of the concave-convex shape in the observation area provided on the outer surface of the photosensitive component, the one-dimensional radial distribution function p(r) obtained by integrating the two-dimensional power spectrum F(r,θ) along the θ direction has at least one maximum value, and when the angle distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at the frequency rp where the one-dimensional radial distribution function p(r) has a maximum value, the power value varies by less than 15% over the entire θ range.

[0045] As a result of research conducted by the inventors, it was found that when... Figure 1A When the outer surface of the electrophotographic photosensitive component shown has a concave-convex shape and the concave-convex shape has a predetermined periodicity, the effects of the present invention can be obtained to a high degree.

[0046] While there are no particular limitations on the methods for obtaining the periodicity of concave and convex shapes, one method can be used: obtaining height information by observing the outer surface of the electrophotographic photosensitive component, and then analyzing the obtained results using a two-dimensional Fourier transform.

[0047] Specifically, when the height information of the concave-convex shape is obtained with the number of data points N1 × N2, the height at any point (n, m) within the surface is h. n,m When the two-dimensional power spectrum P(k,l) obtained by discrete Fourier transform is represented by the following equation (II).

[0048]

[0049] Here, f k,l It is represented by the following equation (III).

[0050]

[0051] Where k and l represent the frequency along the horizontal direction and the frequency along the vertical direction, respectively.

[0052] Furthermore, the spectrum obtained by transforming the two-dimensional power spectrum P(k,l) obtained from equation (II) from the rectangular coordinate system (k,l) to the polar coordinate system (r,θ) is represented by the two-dimensional power spectrum F(r,θ). Here, r and θ satisfy the following equations (IV) and (V), respectively.

[0053]

[0054]

[0055] In this invention, height information measured at regular intervals of less than 0.25 μm along each of two directions of a square in a square observation area with a side length of 200 μm is used for analysis.

[0056] Figures 2A to 2C A figure illustrating an example of the results obtained through numerical analysis of the electrophotographic photosensitive element according to the present invention. Figure 2A A graph is shown illustrating the two-dimensional power spectrum F(r,θ) obtained by analyzing frequencies based on the irregular shape of the outer surface of an electrophotographic photosensitive component. Furthermore, Figure 2B A plot of the one-dimensional radial distribution function obtained by integrating the obtained two-dimensional power spectrum F(r,θ) along the θ direction is shown. Furthermore, Figure 2C This is a graph showing the variation of power values ​​over the entire range of θ when the angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at the frequency rp where the one-dimensional radial distribution function p(r) has a maximum value.

[0057] like Figure 2B As shown, in the electrophotographic photosensitive component according to the present invention, the radial distribution function p(r), obtained by radially converting the two-dimensional power spectrum F(r,θ) into one dimension, has at least one maximum value. This means that the concave and convex portions on the outer surface of the electrophotographic photosensitive component are distributed at regular intervals.

[0058] In addition, such as Figure 2C As shown, when calculating the angular distribution q(θ) of F(rp,θ) at the frequency rp where the radial distribution function p(r) has a maximum value, the variation of the power value over the entire θ range is preferably less than 15%. Therefore, toner slippage is effectively suppressed. This means that when the variation of the power value is low, the ridges of the convex portion of the concave-convex shape extend in various directions and the concave-convex shape is uniform in each direction.

[0059] The frequency rp where the radial distribution function p(r) has a maximum value is preferably between 0.05 and 0.17 μm. -1 Within this range, toner slippage can be effectively suppressed and excellent transfer properties can be obtained. When the frequency rp is 0.05μm... -1 At the above times, the contact area between the outer surface of the photosensitive element and the cleaning blade is reduced, and the effect of reducing the friction between the outer surface of the photosensitive element and the cleaning blade can be obtained to a high degree. When the frequency rp is 0.17μm... -1 At this point, the inorganic particles exposed from the recess become more likely to make point contact with the toner.

[0060] The depth of the uneven shape is preferably 1.0 μm or less. Therefore, the inorganic particles can easily make point contact with the toner. More preferably, the depth of the uneven shape is 0.1 to 1.0 μm. When the depth of the uneven shape is 0.1 μm or more, a high level of reduction in friction between the outer surface of the photosensitive element and the cleaning blade can be achieved. A method for measuring the depth of the uneven shape will be described subsequently.

[0061] like Figure 3 As shown, the electrophotographic photosensitive member according to the invention includes inorganic particles in a surface layer, and a portion of all the inorganic particles in the surface layer corresponds to inorganic particles d partially exposed from recesses c of an uneven shape formed on the outer surface of the electrophotographic photosensitive member. The inorganic particles have low elasticity, which is advantageous because it allows for a smaller contact area between the surface of the toner and the surface of the particles when in contact with the toner.

[0062] Examples of inorganic particles included in the surface layer may include, for example, magnesium oxide, zinc oxide, lead oxide, tin oxide, tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, germanium oxide, tin oxide, titanium oxide, niobium oxide, molybdenum oxide, vanadium oxide, copper aluminum oxide, tin oxide doped with antimony ions, and hydrotalcite particles. These particles may be used alone or in combination of two or more. Silica particles are preferably used as inorganic particles.

[0063] As silica particles, known silica particles can be used, and particles of dry silica or wet silica can be used. Preferably, the silica particles are particles of wet silica obtained by the sol-gel method (hereinafter also referred to as "sol-gel silica").

[0064] Sol-gel silica can be hydrophilic particles or particles with a surface treated and hydrophobicated. Preferably, sol-gel silica is composed of surface-treated and hydrophobic particles. By hydrophobizing the surface of the silica particles, the silica particles become easier to disperse in the surface layer and easier to expose from the surface of the surface layer.

[0065] In the sol-gel process, examples of hydrophobic treatment methods may include methods that remove solvent from the sol-gel dispersion, dry the sol-gel dispersion, and then apply a treatment using a hydrophobic agent; and methods that directly add the hydrophobic agent to the sol-gel dispersion and apply the treatment while drying. From the viewpoint of controlling the half-width of the particle size distribution and controlling the amount of saturated water adsorbed, the method of directly adding the hydrophobic agent to the sol-gel dispersion is preferred.

[0066] Examples of hydrophobicating agents may include the following: chlorosilanes, such as methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tert-butyldimethylchlorosilane, and vinyltrichlorosilane; alkoxysilanes, such as tetramethoxysilane, methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, o-methylphenyltrimethoxysilane, p-methylphenyltrimethoxysilane, n-butyltrimethoxysilane, isobutyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, dodecyltrimethoxysilane, etc. oxysilanes, tetraethoxysilanes, methyltriethoxysilanes, dimethyldiethoxysilanes, phenyltriethoxysilanes, diphenyldiethoxysilanes, isobutyltriethoxysilanes, decyltriethoxysilanes, vinyltriethoxysilanes, γ-methacryloyloxypropyltrimethoxysilanes, γ-glycidyletheroxypropyltrimethoxysilanes, γ-glycidyletheroxypropylmethyldimethoxysilanes, γ-mercaptopropyltrimethoxysilanes, γ-chloropropyltrimethoxysilanes, γ-aminopropyltrimethoxysilanes, γ-aminopropyltriethoxysilanes, γ-(2-aminoethyl) Aminopropyltrimethoxysilane and γ-(2-aminoethyl)aminopropyldimethoxysilane; silazanes, such as hexamethyldisilazane, hexaethyldisilazane, hexapropyldisilazane, hexabutyldisilazane, hexapentyldisilazane, hexahexyldisilazane, hexacyclohexyldisilazane, hexaphenyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane; silicone oils, such as dimethyl silicone oil, methylhydrosilicone oil, methylphenyl silicone oil, alkyl-modified silicone oil, chloroalkyl-modified silicone oil, chlorophenyl-modified silicone oil, fatty acid-modified silicone oil, polyether-modified silicone oil, alkoxy... Modified silicone oils, methanol-modified silicone oils, amino-modified silicone oils, fluorinated silicone oils, and terminally reactive silicone oils; siloxanes, such as hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, hexamethyldisiloxane, and octamethyltrisiloxane; and their fatty acids and metal salts, such as long-chain fatty acids like undecanoic acid, lauric acid, tridecanoic acid, dodecanoic acid, myristic acid, palmitic acid, pentadecanoic acid, stearic acid, heptadecanoic acid, arachidic acid, lignic acid, oleic acid, linoleic acid, and arachidonic acid, as well as salts of said fatty acids with metals such as zinc, iron, magnesium, aluminum, calcium, sodium, and lithium.

[0067] Alkoxysilanes, silazanes, and silicone oils are preferred because they are easy to hydrophobize. The hydrophobizing agents can be used alone or in combination of two or more.

[0068] The volume average particle size of the inorganic particles is preferably 50 to 550 nm. When inorganic particles with the aforementioned volume average particle size are used, it is easy to expose the concave portions of the surface layer, which are uneven in shape. Furthermore, it is easy to reduce the contact area with the toner because the surface curvature of the inorganic particles is high.

[0069] When the outer surface of the electrophotographic photosensitive component according to the present invention is observed from above at a predetermined magnification using a scanning electron microscope, such as Figure 4 As shown, inorganic particles d can be observed protruding from the convex portion c of the concave-convex shape. In this case, when the total area of ​​the exposed portion of the inorganic particles in the concave portion is defined as S1 and the total area of ​​the concave portion excluding the exposed portion of the inorganic particles is defined as S2, S1 / (S1+S2) (hereinafter also referred to as "coverage") is preferably 0.20 to 0.80.

[0070] When the coverage ratio is 0.20 or higher, the contact area between the toner and the inorganic particles not exposed on the outer surface of the photosensitive element can be reduced, and the effect of reducing toner adhesion and improving the transferability of the photosensitive element can be obtained to a high degree. An excessively high proportion of inorganic particles exposed from the recesses results in a shorter distance between the toner and the inorganic particles in contact, leading to an increase in the contact area between the toner and the inorganic particles exposed on the outer surface of the photosensitive element. When the coverage ratio is 0.80 or lower, the distance between the toner and the inorganic particles in contact can be appropriately ensured, and the effect of improving the transferability of the photosensitive element can be obtained to a high degree. A coverage ratio of 0.25 to 0.60 is more preferable.

[0071] The following describes the configuration of the electrophotographic photosensitive element according to the present invention.

[0072] [Electronic photographic sensor]

[0073] The electrophotographic photosensitive component according to the present invention comprises, in sequence, a support, a photosensitive layer, and a surface layer. The electrophotographic photosensitive component according to the present invention may further include a conductive layer and a base layer between the support and the photosensitive layer.

[0074] Examples of methods for producing electrophotographic photosensitive components may include preparing coating solutions for each layer, applying them to a support in a desired order, and drying the coating solutions. In this case, examples of coating methods may include dip coating, spray coating, inkjet coating, roller coating, die coating, blade coating, curtain coating, wire rod coating, and ring coating. Dip coating is preferred from the viewpoint of efficiency and productivity.

[0075] The support structure and each layer will be described below.

[0076] <Support Body>

[0077] In this invention, the electrophotographic photosensitive component includes a support. The support is preferably a conductive support (conductive support). Furthermore, examples of the support's shape can include, for example, a cylindrical shape, a strip shape, and a sheet shape. A cylindrical shape is preferred. Additionally, the surface of the support can be subjected to electrochemical treatments such as anodizing, sandblasting, or machining.

[0078] Metals, resins, and glass are preferred materials for supporting structures.

[0079] Examples of metals may include aluminum, iron, nickel, copper, gold, and stainless steel, or alloys thereof. Among these, aluminum supports obtained by using aluminum are preferred.

[0080] In addition, the resin or glass can be made conductive through treatments such as mixing with a conductive material or coating with a conductive material.

[0081] <Conductive Layer>

[0082] In this invention, a conductive layer can be provided on the support. By providing the conductive layer, scratches or unevenness on the surface of the support can be shielded, or the reflection of light on the surface of the support can be controlled.

[0083] The conductive layer preferably comprises conductive particles and resin.

[0084] Examples of materials that can produce conductive particles include metal oxides, metals, and carbon black.

[0085] Examples of metal oxides may include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of metals may include aluminum, nickel, iron, nickel-chromium alloys, copper, zinc, and silver.

[0086] Preferably, metal oxides are used for the conductive particles. In particular, titanium oxide, tin oxide, or zinc oxide are more preferably used for the conductive particles.

[0087] When metal oxides are used in conductive particles, the surface of the metal oxide can be treated with silane coupling agents, or the metal oxide can be doped with elements such as phosphorus or aluminum, or their oxides.

[0088] Furthermore, the conductive particles can have a layered structure comprising a core particle and a coating layer covering the core particle. Examples of materials for the core particle include titanium oxide, barium sulfate, and zinc oxide. Examples of materials for the coating layer include metal oxides such as tin oxide.

[0089] Furthermore, when metal oxides are used for conductive particles, the volume average particle size of the conductive particles is preferably 1 to 500 nm, and more preferably 3 to 400 nm.

[0090] Examples of resins may include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, and alkyd resins.

[0091] In addition, the conductive layer may further contain masking agents such as silicone oil, resin particles, or titanium dioxide.

[0092] The thickness of the conductive layer is preferably 1 to 50 µm, and particularly preferably 3 to 40 µm.

[0093] A conductive layer can be formed by preparing a coating solution containing the aforementioned materials and solvents, forming a coating film thereon, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Examples of methods for dispersing conductive particles in the coating solution for the conductive layer include methods using a paint mixer, a sand mill, a ball mill, and a liquid impact high-speed disperser.

[0094] <Undercoat>

[0095] In this invention, a primer layer can be formed on the support or conductive layer. By forming a primer layer, the interlayer adhesion can be improved, thereby providing a charge injection prevention function.

[0096] The primer layer preferably comprises a resin. Alternatively, the primer layer can be formed into a cured film by polymerization of a composition comprising monomers having polymerizable functional groups.

[0097] Examples of resins may include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinylphenolic resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamide-imide resins, and cellulose resins.

[0098] Examples of polymerizable functional groups included in monomers having polymerizable functional groups may include isocyanate groups, terminal isocyanate groups, hydroxymethyl groups, alkylated hydroxymethyl groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic anhydride groups, and carbon-carbon double bond groups.

[0099] Furthermore, the base coating may further include electron transport materials, metal oxides, metals, and conductive polymers to improve electrical properties. Preferably, electron transport materials or metal oxides are used.

[0100] Examples of electron transport materials may include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadiene compounds, fluorenone compounds, xanthonesone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, thiophene compounds, and boron-containing compounds. Electron transport materials having polymerizable functional groups can be used as electron transport materials and copolymerized with the aforementioned monomers having polymerizable functional groups to form a base coating as a cured film.

[0101] Examples of metal oxides may include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals may include gold, silver, and aluminum.

[0102] In addition, the base coat may contain additives.

[0103] The thickness of the base coating is preferably 0.1 to 50 µm, more preferably 0.2 to 40 µm, and particularly preferably 0.3 to 30 µm.

[0104] The base coat can be formed by preparing a coating liquid containing the above-described materials and solvents, forming the coating film thereon, and drying and / or curing the coating film. Examples of solvents used in the coating liquid include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0105] <Photosensitive layer>

[0106] The photosensitive layer of an electrophotographic photosensitive component is mainly divided into (1) a stacked photosensitive layer and (2) a single-layer photosensitive layer. (1) A stacked photosensitive layer includes a charge-generating layer containing a charge-generating substance and a charge-transporting layer containing a charge-transporting substance. (2) A single-layer photosensitive layer includes a photosensitive layer containing both a charge-generating substance and a charge-transporting substance. The electrophotographic photosensitive component according to the present invention preferably includes a stacked photosensitive layer.

[0107] (1) Layered photosensitive layer

[0108] A stacked photosensitive layer includes a charge generation layer and a charge transport layer.

[0109] (1-1) Charge generation layer

[0110] The charge-generating layer preferably comprises a charge-generating substance and a resin.

[0111] Examples of charge-generating substances may include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, azo pigments and phthalocyanine pigments are preferred. Of the phthalocyanine pigments, titanium dioxide phthalocyanine pigments, gallium chloride phthalocyanine pigments, and hydroxy gallium phthalocyanine pigments are preferred.

[0112] The content of charge-generating material in the charge-generating layer is preferably 40 to 85% by mass relative to the total mass of the charge-generating layer, and more preferably 60 to 80% by mass.

[0113] Examples of resins may include polyester resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins. Among these, polyvinyl butyral resins are more preferred.

[0114] Furthermore, the charge-generating layer may further contain additives such as antioxidants or ultraviolet absorbers. Specific examples may include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0115] The thickness of the charge generation layer is preferably 0.1 to 1 µm, and more preferably 0.15 to 0.4 µm.

[0116] The charge-generating layer can be formed by preparing a coating solution containing the above-described materials and solvents, forming a coating film thereon, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0117] (1-2) Charge transport layer

[0118] The charge transport layer preferably comprises a charge transport material and a resin.

[0119] Examples of charge-transporting substances may include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds or benzidine compounds are preferred, and compounds represented by the following formula (1) are suitably used.

[0120]

[0121] In equation (1), R 1 To R 10 Each can be used independently to represent a hydrogen atom or a methyl group.

[0122] Examples of structures represented by formula (1) are shown in formulas (1-1) to (1-10). Among them, compounds having structures represented by formulas (1-1) to (1-6) are more preferred.

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133] Thermoplastic resins are used as the resin, and examples of the resin may include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. As a polyester resin, polyarylate resins are particularly preferred.

[0134] The content of charge transport material in the charge transport layer is preferably 25 to 70% by mass relative to the total mass of the charge transport layer, and more preferably 30 to 55% by mass.

[0135] The ratio (mass ratio) of charge transport material to resin is preferably 4:10 to 20:10, and more preferably 5:10 to 12:10.

[0136] In addition, the charge transport layer may also contain additives such as antioxidants, ultraviolet absorbers, plasticizers, leveling agents, slip-improving agents, or abrasion resistance improvers. Specific examples may include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluoropolymer particles, polystyrene resin particles, polyethylene resin particles, alumina particles, and boron nitride particles.

[0137] The thickness of the charge transport layer is preferably 5 to 50 µm, more preferably 8 to 40 µm, and particularly preferably 10 to 30 µm.

[0138] (2) Single-layer photosensitive layer

[0139] A single-layer photosensitive layer can be formed by preparing a coating solution containing a charge-generating substance, a charge-transporting substance, a resin, and a solvent, forming the coating film, and drying the coating film. Examples of charge-generating substances, charge-transporting substances, and resins are similar to those exemplified in the materials described in "(1) Layered Photosensitive Layers" above.

[0140] <Protective Layer>

[0141] The electrophotographic photosensitive component according to the present invention includes a protective layer as a surface layer. The protective layer comprises an adhesive resin and inorganic particles as described above. The protective layer is formed into a cured film by polymerizing the compound having polymerizable functional groups in a composition comprising a compound having polymerizable functional groups. In this case, the adhesive resin included in the protective layer comprises a polymerized product of the compound having polymerizable functional groups.

[0142] Examples of polymerizable functional groups included in monomers having polymerizable functional groups may include acryloyloxy and methacryloyloxy.

[0143] Materials with charge-transporting capabilities can be used as monomers with polymerizable functional groups. As a charge-transporting structure, a triarylamine structure is preferred in terms of charge transport. Examples of polymerizable functional groups included in charge-transporting materials may include acryloyloxy and methacryloxy.

[0144] The monomer containing polymerizable functional groups may contain one or more polymerizable functional groups. In order to facilitate the elimination of strain generated in the polymerization of multiple polymerizable functional groups, it is particularly preferred to form a cured film by polymerizing a composition containing both a compound having multiple polymerizable functional groups and a compound having one polymerizable functional group.

[0145] Examples of compounds having a polymerizable functional group are shown in formulas (2-1) to (2-6).

[0146]

[0147]

[0148]

[0149]

[0150]

[0151]

[0152] Examples of compounds having multiple polymerizable functional groups are shown in formulas (3-1) to (3-7).

[0153]

[0154]

[0155]

[0156]

[0157]

[0158]

[0159]

[0160] The protective layer preferably further comprises conductive particles and / or charge transport substances, and resin.

[0161] Examples of conductive particles may include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0162] Examples of charge-transporting substances may include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from these substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0163] Examples of resins may include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenolic resins, melamine resins, and epoxy resins. Among these, polycarbonate resins, polyester resins, and acrylic resins are preferred.

[0164] The protective layer may also contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, slip-improving agents, or abrasion resistance enhancers. Specific examples may include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluoropolymer particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0165] The thickness of the protective layer is preferably 0.2 to 5.0 µm, thereby forming a fine and uniform uneven shape. The thickness of the protective layer is more preferably 0.2 to 4.0 µm, and even more preferably 0.2 to 3.0 µm.

[0166] A protective layer can be formed by preparing a coating liquid containing various materials and solvents, forming the coating film thereon, and drying and / or curing the coating film. Examples of solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[0167] <Method for forming uneven shapes on the outer surface of an electrophotographic photosensitive component>

[0168] Examples of methods for forming irregular shapes on the outer surface of an electrophotographic photosensitive component include (1) a method of stacking and pressing films with different Young's moduli, and (2) a method of forming a structure by imprinting. Method (1) requires a structure in which a relatively hard and thin film is in close contact with the surface of a relatively soft material. In this structure, the surface layer is buckled (bend) due to compressive stress along the surface direction. Method (2) is a method of forming a pattern by pressing a mold, such as a metal, against the outer surface, and is well known as a technique for giving a surface shape to a photosensitive component. Other methods, such as laser ablation, may also be used.

[0169] The following describes the method for forming concave and convex shapes (1).

[0170] In the case of a laminated photosensitive layer, a protective layer is formed on a charge transport layer whose main component is a thermoplastic resin; or in the case of a monolayer photosensitive layer, a protective layer formed by polymerizing a crosslinking monomer is formed on a monolayer photosensitive layer whose main component is a thermoplastic resin. In this case, the composition (coating liquid for protective layer) containing a compound having polymerizable functional groups used to form the protective layer contains inorganic particles. An uneven shape is formed by applying a heat treatment after the protective layer is formed.

[0171] The mechanism by which the uneven shape is formed is considered to be as follows: During heat treatment, compressive stress is applied due to the difference in deformation between the protective layer and the charge transport layer or the monolayer photosensitive layer, causing the protective layer to bend and form an uneven shape on the outer surface of the photosensitive component. Since the protective layer tends to bend uniformly across the entire surface of the photosensitive component, such as... Figure 1A and Figure 1B As shown in the example, the ridges of the raised parts of the concave-convex shape are formed randomly and uniformly in each direction, causing the electrophotographic photosensitive component to exhibit wrinkles.

[0172] Preferably, the heating temperature used to form the uneven shape is set to a temperature exceeding the boiling point of the residual solvent contained in the photosensitive layer. Furthermore, while the heating temperature should be determined based on the boiling point of the solvent used, it is more preferable to set the heating temperature to 140 to 230°C. When the heating temperature is set to a temperature exceeding the boiling point of the residual solvent, the residual solvent in the photosensitive layer evaporates rapidly, and the points where the residual solvent evaporates tend to become the starting points of bending, and the uneven shape tends to be fine and uniformly formed.

[0173] A photosensitive layer is formed by applying a coating solution for a photosensitive layer to form a coating film, heating the film, and drying the film. Examples of solvents for the coating solution for a photosensitive layer may include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Specifically, examples of solvents may include toluene, xylene (including at least one selected from the group consisting of o-xylene, m-xylene, and p-xylene), methyl benzoate, cyclohexanone, diethylene glycol monoethyl ether acetate, tetrahydrofuran, and dimethoxymethane. Since a suitable amount of solvent tends to remain in the photosensitive layer, it is preferable to combine solvents with a boiling temperature of 140°C or higher with solvents with a boiling temperature below that temperature.

[0174] Known methods can be used to measure the amount of residual solvent, and gas chromatography can be used, for example.

[0175] The coating liquid for the protective layer contains compounds with chain-polymerizable functional groups.

[0176] The protective layer is formed into a cured film by coating a protective layer with a coating liquid and polymerizing a compound with chain-polymerizable functional groups.

[0177] Examples of reactions that polymerize a composition containing monomers having polymerizable functional groups can include methods using heat, light (e.g., ultraviolet light), or radiation (e.g., an electron beam). Radiation is preferred, and within radiation, an electron beam is more preferred. Furthermore, the temperature needs to be raised to a sufficient level to allow for sufficient polymerization within a short time to form a cured film. Heating is preferably carried out in a low-oxygen atmosphere to rapidly polymerize while preventing deactivation through free radical formation. The heating temperature is preferably not higher than the boiling point of the residual solvent in the photosensitive layer, and specifically, preferably 90 to 130°C.

[0178] [Processing box and electrophotographic equipment]

[0179] According to the present invention, the processing box integrally supports the above-mentioned electrophotographic photosensitive component and at least one unit selected from the group consisting of a charging unit, a developing unit and a cleaning unit, and is detachably mounted to the main body of the electrophotographic device.

[0180] Furthermore, the electrophotographic apparatus according to the present invention includes the aforementioned electrophotographic photosensitive component, charging unit, exposure unit, developing unit, and transfer unit.

[0181] An example of an illustrative configuration of an electrophotographic device having a processing box 11 including an electrophotographic photosensitive element 1 is shown in Figure 5 As shown in the image.

[0182] The cylindrical electrophotographic photosensitive element 1 is driven to rotate around axis 2 at a predetermined circumferential speed in the direction of the arrow. The surface of the electrophotographic photosensitive element 1 is charged to a predetermined positive or negative potential using a charging unit 3. Although in Figure 5 The diagram shows a roller charging system using a roller-type charging unit 3, but charging systems such as corona charging systems, proximity charging systems, or injection charging systems can also be used. The surface of the charged electrophotographic photosensitive member 1 is irradiated with exposure light 4 emitted from an exposure unit (not shown), forming an electrostatic latent image corresponding to target image information on the surface of the electrophotographic photosensitive member 1. The electrostatic latent image formed on the outer surface of the electrophotographic photosensitive member 1 is developed using toner stored in a developing unit 5, forming a toner image on the surface of the electrophotographic photosensitive member 1. The toner image formed on the surface of the electrophotographic photosensitive member 1 is transferred to a transfer material 7 by a transfer unit 6. The transfer material 7, on which the toner image is transferred, is conveyed to a fixing unit 8 for fixing the toner image. Thus, the transfer material 7 is printed to the exterior of the electrophotographic apparatus. The electrophotographic apparatus may also include a cleaning unit 9 for removing residues such as toner remaining on the surface of the electrophotographic photosensitive member 1 after transfer. The electrophotographic device may also include a static removal mechanism that performs static removal treatment on the surface of the electrophotographic photosensitive member 1 using pre-exposure light 10 from a pre-exposure unit (not shown). Furthermore, a guide unit 12, such as a guide rail, may be provided to detachably mount the processing box 11 to the main body of the electrophotographic device.

[0183] The electrophotographic photosensitive element according to the present invention can be used, for example, in laser beam printers, LED printers, copiers, fax machines, and multifunction printers.

[0184] [Evaluation methods for uneven shapes and inorganic particles]

[0185] The following describes a method for evaluating the unevenness of the outer surface of an electrophotographic photosensitive component and the inorganic particles contained in the surface layer.

[0186] <Evaluation methods for the unevenness and depth of the unevenness on the outer surface of photosensitive components>

[0187] The outer surface of the electrophotographic photosensitive component was magnified and observed using a laser microscope (VK-X200, manufactured by Keyence Corporation) to obtain height information regarding its uneven shape. The observation area consisted of a square shape with sides of 200 μm, comprising 19 line segments dividing the electrophotographic photosensitive component into 20 equal parts along its axial direction, and 4 line segments dividing the photosensitive component into 4 equal parts along its circumference, with each segment serving as its center point. The orientation of each observation area was set such that one side of the square was parallel to the circumference of the electrophotographic photosensitive component. Height information was obtained by applying tilt correction to correct the cylindrical shape of the photosensitive component to a planar shape.

[0188] Next, in the image obtained through observation, including the concave and convex shapes, a reference line L1 is set that passes through the center point of the observation area and is parallel to the circumferential direction of the electrophotographic photosensitive element. Furthermore, reference lines L2 to L1,800 are set by rotating the reference line L1 around the center point at 0.1° intervals.

[0189] Subsequently, for each of the reference lines L1 to L1,800, the following is confirmed: Each of the reference lines L1 to L1,800 intersects the edge of the convex portion of the concave-convex shape at multiple locations, and the angle of intersection between each of the reference lines L1 to L1,800 and the edge has different values ​​at at least two locations selected from the multiple locations.

[0190] For the measurement of the depth of the concave-convex shape, the maximum valley depth Rv is determined by analyzing the line roughness (JIS B 0601-2001) of the baseline L1 set in the observation area using height information analysis. The arithmetic mean of the Rv values ​​determined for each of the 76 observation areas is defined as the depth of the concave-convex shape.

[0191] <Methods for measuring the frequency (rp) and power value changes of the unevenness / concavity on the outer surface of a photosensitive component>

[0192] The two-dimensional power spectrum F(r,θ) is obtained by performing frequency analysis on the height information of the concave-convex shape obtained above. Then, the one-dimensional radial distribution function p(r) is calculated and the frequency rp where p(r) has a maximum value is found.

[0193] Furthermore, for the frequency rp where p(r) has a maximum value, the angular distribution q(θ) of the two-dimensional power spectrum F(r,θ) is obtained to determine the variation of the power value over the entire θ range.

[0194] <Methods for measuring the volume average particle size of inorganic particles>

[0195] Volume average particle size was measured using a Zetasizer Nano-ZS (manufactured by Malvern). This device measures particle size using dynamic light scattering. First, the inorganic particles to be measured were diluted and adjusted to a solid-liquid ratio of 0.10 wt% (±0.02 wt%). The diluted solution was collected in a quartz cell and placed in the measuring unit. Water or a mixture of methyl ethyl ketone / methanol was used as the dispersion medium. The refractive index of the inorganic particles, the refractive index of the dispersion solvent, viscosity, and temperature were input and measured using Zetasizer software 6.30. Dv was used as the volume average particle size.

[0196] For the refractive index of inorganic particles, refer to "Refractive Index of Solids" in Handbook of Chemistry, Basic Edition, Revised 5th Edition (edited by the Chemical Society of Japan, Maruzen Co., Ltd.), Volume II, page 642. The refractive index, viscosity, and temperature of the dispersion solvent are selected from values ​​included in the control software. In the case of mixed solvents, the weight average of the dispersion solvents to be mixed is used.

[0197] <Methods for confirming the exposure status of inorganic particles in concave and convex shapes and methods for measuring coverage>

[0198] Based on the height information of the observation area with a square side length of 200 μm obtained above, the total height H corresponding to the height from the highest point to the lowest point of the concave-convex shape is determined. For example... Figure 3 As shown, the portion with a height less than half of the total height H is defined as the concave portion c of the convex-concave shape. For each observation area, the concave portion c of the convex-concave shape is determined.

[0199] When viewed from above the outer surface of the electrophotographic photosensitive component, it is determined whether inorganic particles are exposed from the recesses of the uneven shape. The coverage is calculated by S1 / (S1+S2), where S1 is defined as the total area of ​​the exposed portion of the inorganic particles in the recess, and S2 is defined as the total area of ​​the recess excluding the exposed portion of the inorganic particles.

[0200] For the observation points used to confirm the exposure status of inorganic particles and to measure the print rate, each of the other 19 points (a total of 10 positions) from one end of the 76 center points of the observation area along the same axis was used. The areas, each having a square with a side length of 15 μm and including the 10 positions used as their respective center points, were observed using a scanning electron microscope (SEM) ("S-4800", manufactured by JEOL Ltd.), wherein one side of the square area was parallel to the circumferential direction of the photosensitive element.

[0201] Next, a scanner acquires a photographic image of the photosensitive component using a scanning electron microscope. Image processing software (Image J) is used for image analysis and binarization of the particles in the photographic image. The concave-convex shape of the recesses is identified beforehand using a laser microscope. The total area of ​​the exposed portion of the inorganic particles in the recesses is defined as S1, and the total area of ​​the recesses excluding the exposed portion of the inorganic particles is defined as S2. The coverage rate S1 / (S1+S2) is then calculated. For a total of 10 locations, the coverage rate is calculated as described above, and the arithmetic mean of the obtained coverage rates is defined as the coverage rate of the concave-convex shape of the inorganic particles on the outer surface of the photosensitive component.

[0202] According to the present invention, an electrophotographic photosensitive component can be provided that can reduce friction with the cleaning scraper, exhibit high cleaning performance and excellent transferability when used in low temperature and low humidity environments.

[0203] Example

[0204] The present invention is described in more detail below by way of examples and comparative examples. The present invention is by no means limited to the following examples, and various modifications can be made without departing from the spirit of the invention. In the following description of the examples, unless otherwise stated, "parts" are by mass. The film thickness of each layer of the electrophotographic photosensitive component according to the examples and comparative examples was determined using an eddy current thickness gauge (Fischerscope, manufactured by Fischer Instruments KK) or by converting the mass of the layer per unit area to its thickness using its specific gravity.

[0205] (Particles)

[0206] The particles 1 to 7 used to form the protective layer (surface layer) in the examples and comparative examples are shown in Table 1. Particles 1 to 6 are silica particles (inorganic particles) and particle 7 is a silicone resin particle. In addition, particles 4 to 6 are particles with a hydrophobic surface treatment.

[0207] [Table 1]

[0208]

[0209] (Preparation of surface-treated particles 1)

[0210] Please provide the following materials.

[0211] 10 parts methanol

[0212] Five portions of particle 1 (shown in Table 1)

[0213] These substances were mixed and dispersed at room temperature for 30 minutes using an ultrasonic homogenizer. Next, 0.25 parts by weight of n-propyltrimethoxysilane ("KBM-3033" manufactured by Shin-Etsu Chemical Co., Ltd.) and 10 parts by weight of toluene were added as a reactive surface treatment agent, and mixed at room temperature for 60 minutes. After removing the solvent using an evaporator, the product was heated at 140°C for 60 minutes to prepare surface-treated particles 1 treated with the reactive surface treatment agent.

[0214] (Preparation of surface-treated particles 2)

[0215] Except that particle 2 is used instead of particle 1, surface-treated particles 2 are prepared in the same manner as in the preparation of surface-treated particles 1.

[0216] (Preparation of surface-treated particles 3)

[0217] Except that particle 3 is used instead of particle 1, surface-treated particles 3 are prepared in the same manner as in the preparation of surface-treated particles 1.

[0218] <Production of Electrophotographic Photosensitive Components>

[0219] [Example 1]

[0220] An aluminum cylinder (JIS-A3003, aluminum alloy) with a diameter of 24 mm and a length of 257.5 mm is used as the support (conductive support).

[0221] Next, the following materials are provided.

[0222] 214 portions of titanium oxide (TiO2) particles coated with oxygen-deficient tin oxide (SnO2) as metal oxide particles (average primary particle size 230 nm).

[0223] 132 parts of phenolic resin (monomer / oligomer of phenolic resin) as a binder material (trade name: Plyophen J-325, resin solid content: 60% by mass, manufactured by DIC Corporation)

[0224] 98 parts of 1-methoxy-2-propanol as solvent

[0225] The materials were placed in a sand mill containing 450 parts of glass beads with a diameter of 0.8 mm and dispersed at a rotation speed of 2,000 rpm, a dispersion time of 4.5 hours, and a cooling water temperature of 18°C ​​to obtain a dispersion. The glass beads were removed from the dispersion using a sieve (aperture: 150 µm). Silicone resin particles (trade name: TOSPEARL 120, average particle size 2 μm, manufactured by Momentive Performance Materials, Inc.) as a surface roughening agent were added to the obtained dispersion. The amount of silicone resin particles added was set to 10% by mass relative to the total mass of metal oxide particles and binder material in the dispersion after the glass beads were removed. In addition, silicone oil (trade name: SH28PA, manufactured by Dow Corning Toray Co., Ltd.) as a leveling agent was added to the dispersion such that the content of silicone oil was 0.01% by mass relative to the total mass of metal oxide particles and binder material in the dispersion. Next, a solvent consisting of a mixture of methanol and 1-methoxy-2-propanol (mass ratio: 1:1) was added to the dispersion so that the total mass of the metal oxide particles, binder material, and surface roughening agent in the dispersion (i.e., the mass of the solid component) was 67% by mass relative to the mass of the dispersion. Subsequently, a coating solution for the conductive layer was prepared by stirring the mixture. The coating solution for the conductive layer was then applied to the support by dip coating and heated at 140°C for 1 hour, thereby forming a conductive layer with a film thickness of 30 µm.

[0226] Next, the following materials are provided.

[0227] 4 portions of electron transport material represented by the following formula E-1

[0228]

[0229] 5.5 parts of capped isocyanate (trade name: Duranate SBN-70D, manufactured by Asahi Kasei Corporation)

[0230] 0.3 parts polyvinyl butyral resin (trade name: S-LEC KS-5Z, manufactured by SEKISUI CHEMICAL CO.,LTD.)

[0231] 0.05 parts of zinc hexanoate(II) as a catalyst (manufactured by Mitsuwa Chemical Co., Ltd.)

[0232] These materials were dissolved in a solvent containing 50 parts tetrahydrofuran and 50 parts 1-methoxy-2-propanol to prepare a primer coating solution. The primer coating solution was applied to the conductive layer by dip coating, and the layer was heated at 170°C for 30 minutes to form a primer coating with a film thickness of 0.7 μm.

[0233] Next, the following materials are provided.

[0234] Ten samples of crystalline hydroxygallium phthalocyanine with peaks at 7.5° and 28.4° in the CuKα characteristic X-ray diffraction pattern.

[0235] 5 parts polyvinyl butyral resin (trade name: S-LEC BX-1, manufactured by SEKISUI CHEMICAL CO., LTD.)

[0236] These materials were added to 200 parts of cyclohexanone and dispersed for 6 hours using a sand mill with glass beads of 0.9 mm diameter. 150 parts of cyclohexanone and 350 parts of ethyl acetate were further added to dilute the mixture, thereby obtaining a coating solution for the charge-generating layer. The obtained coating solution was applied to the primer layer by dip coating and dried at 95°C for 10 minutes to form a charge-generating layer with a film thickness of 0.20 µm.

[0237] X-ray diffraction measurements were performed under the following conditions.

[0238] [Powder X-ray Diffraction Measurement]

[0239] Measuring instrument used: RINT-TTRII X-ray diffractometer, manufactured by Rigaku Corporation.

[0240] X-ray tube: Cu

[0241] Tube voltage: 50KV

[0242] Tube current: 300mA

[0243] Scanning method: 2θ / θ scan

[0244] Scanning speed: 4.0° / min

[0245] Sampling interval: 0.02°

[0246] Starting angle (2θ): 5.0°

[0247] Termination angle (2θ): 40.0°

[0248] Attachment: Standard Sample Rack

[0249] Filter: Not used

[0250] Incident monochromator: using

[0251] Counter monochromator: Not used

[0252] Diverging slit: Open

[0253] Longitudinal diverging slit: 10.00mm

[0254] Scattering slit: Open

[0255] Light receiving slit: Open

[0256] Flat monochromator: using

[0257] Counter: Blink Counter

[0258] Next, the following materials are provided.

[0259] Five portions of charge-transporting material (hole-transporting material) represented by equation (1-2)

[0260] Five portions of charge-transporting substances (hole-transporting substances) represented by equation (1-3)

[0261] 10 parts polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Engineering-Plastics Corporation)

[0262] 0.02 parts of polycarbonate resin having copolymer units of the following formula (C-4) and the following formula (C-5) (x / y = 0.95 / 0.05: viscosity-average molecular weight = 20,000)

[0263]

[0264]

[0265] These materials were dissolved in a solvent consisting of 60 parts toluene, 20 parts methyl benzoate, and 20 parts dimethoxymethane to prepare a coating solution for the charge transport layer. The coating solution was then applied to the charge generation layer by dip coating to form a coating film for the charge transport layer, and the film was dried at 120°C for 30 minutes to form a charge transport layer with a thickness of 16 µm.

[0266] Next, the following materials are provided.

[0267] 36 portions of granules 4

[0268] 14 compounds represented by formula (2-2)

[0269] 10 portions of the compound represented by formula (3-1)

[0270] 0.1 parts of a siloxane-modified acrylic compound (SYMAC US-270, manufactured by Toagosei Co., Ltd.)

[0271] These materials were mixed with 58 parts cyclohexane and 25 parts 1-propanol, and the resulting mixture was stirred. The coating solution for the protective layer was prepared as described above.

[0272] A protective coating film is formed by applying a coating liquid to the charge transport layer via dip coating, and the resulting coating film is dried at 40°C for 5 minutes. Subsequently, the coating film is irradiated with an electron beam for 1.6 seconds in a nitrogen atmosphere at an accelerating voltage of 70 kV and a beam current of 5.0 mA, while the support (the irradiated object) is rotated at 300 rpm. The dose at the outermost surface layer is 15 kGy. Then, a first heating is performed by increasing the temperature from 25°C to 100°C over 20 seconds in a nitrogen atmosphere, thereby forming a cured film with a thickness of 1.5 μm. The oxygen concentration from electron beam irradiation to the subsequent heat treatment is below 10 ppm. Next, the coating film is allowed to cool naturally in the atmosphere until the temperature of the coating film reaches 25°C, and then the coating film is subjected to a second heat treatment at 160°C for 15 minutes to form a protective layer with an uneven surface, thereby exhibiting a wrinkled shape. As described above, an electrophotographic photosensitive component according to Example 1 is produced.

[0273] The aforementioned methods were used to evaluate the surface irregularity, depth, frequency (rp), power variation, presence of exposed inorganic particles in the recesses of the irregularity, and coverage of inorganic particles on the outer surface of the electrophotographic photosensitive component. The results are shown in Table 3.

[0274] Regarding concave and convex shapes, cases that satisfy the following conditions are classified as A, and cases that do not satisfy the following conditions are classified as B.

[0275] Conditions: Each of the baselines L1 to L1,800 intersects the edge of the convex part of the concave-convex shape at multiple locations, and the angle of intersection between each of the baselines L1 to L1,800 and the edge has a different value at at least two of the multiple locations.

[0276] Furthermore, for the frequency rp where p(r) has a maximum value, the angular distribution q(θ) of F(rp,θ) is calculated. Then, cases where the power value changes by less than 15% over the entire θ range are classified as A, and cases where the change is greater than 15% are classified as B.

[0277] Furthermore, the case where there are exposed inorganic particles in the concave part of the concave-convex shape is classified as A, and the case where there are no exposed inorganic particles in the concave-convex shape is classified as B.

[0278] [Examples 2 to 16]

[0279] In Example 1, when forming the protective layer, the types and amounts of each compound used, the types and amounts of particles, the film thickness, and the second heating processing conditions were varied as shown in Table 2. Except as described above, the electrophotographic photosensitive components according to Examples 2 to 16 were produced in the same manner as in Example 1. The obtained electrophotographic photosensitive components were measured and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0280] [Table 2]

[0281]

[0282] [Comparative Example 1]

[0283] In Example 1, when forming the protective layer, the film thickness and the second heating processing conditions were changed as shown in Table 2. Except as described above, the electrophotographic photosensitive component according to Comparative Example 1, which does not have an uneven surface, was produced in the same manner as in Example 1. The obtained electrophotographic photosensitive components were measured and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0284] [Comparative Example 2]

[0285] The electrophotographic photosensitive component according to Comparative Example 2, which has no unevenness on its outer surface, was produced in the same manner as in Comparative Example 1. Using... Figure 6 The grinding machine shown grinds the outer surface of the electrophotographic photosensitive component under the following conditions. Thus, an electrophotographic photosensitive component according to Comparative Example 2 is produced, having a plurality of grooves on the outer surface of the electrophotographic photosensitive component that are parallel to each other and extend in the circumferential direction.

[0286] Feed speed of grinding disc: 400 mm / min

[0287] Rotational speed of the electrophotographic photosensitive element: 240 rpm

[0288] Abrasive particles: silicon carbide

[0289] Average particle size of abrasive grains: 3μm

[0290] Grinding time: 20 seconds

[0291] Roughening was performed by pressing the abrasive pad 1-1 against the outer surface of the electrophotographic photosensitive component 1-7 for 20 seconds while feeding the abrasive pad 1-1 in the direction of the arrow and rotating the electrophotographic photosensitive component 1-7 in the direction of the arrow. The abrasive pad 1-1 was formed by forming a layer on a sheet substrate, obtained by dispersing abrasive grains in a binder resin. Here, 1-2 to 1-5 represent guide rollers, 1-6 represents support rollers, 1-8 represents feed rollers, and 1-9 represents take-up rollers. The obtained electrophotographic photosensitive components were measured and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0292] [Comparative Examples 3 to 5]

[0293] In Example 1, when forming the protective layer, the types and amounts of each compound used, the types and amounts of particles, the film thickness, and the second heating processing conditions were varied as shown in Table 2. Except as described above, the electrophotographic photosensitive components according to Comparative Examples 3 to 5 were produced in the same manner as in Example 1. The obtained electrophotographic photosensitive components were measured and evaluated in the same manner as in Example 1. The results are shown in Table 3.

[0294] [Table 3]

[0295]

[0296] <Evaluation>

[0297] The following evaluation was performed on the electrophotographic photosensitive components produced in Examples 1 to 16 and Comparative Examples 1 to 5.

[0298] [Torque Evaluation]

[0299] As an electrophotographic device, a modification of a laser beam printer (trade name: HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard Company) was performed. The modifications included: modifying the electrophotographic device to allow measurement of the drive current of the rotary motor of the electrophotographic photosensitive element; and modifying the electrophotographic device to allow adjustment and measurement of the voltage applied to the charging roller and the intensity of the image exposure light.

[0300] The photosensitive components according to the various embodiments and comparative examples are installed in the cyan box of the image forming apparatus.

[0301] Subsequently, the test image, printed at a 5% print rate, was printed onto 100 sheets of A4-sized plain paper under low temperature and low humidity conditions of 15℃ and 10%RH. Charging conditions were adjusted to achieve a dark area potential of -500V, and exposure conditions were adjusted to achieve an image exposure of 0.25μJ / cm². 2Read the drive current value (current value A) when 100 images are output. The higher the obtained current value, the greater the friction between the electrophotographic photosensitive component and the cleaning blade.

[0302] Furthermore, the electrophotographic photosensitive component is produced as follows. Except that the particle 4 is not used and the treatment in the second heating step is performed at 100°C for 10 minutes to prevent the formation of uneven shapes, the electrophotographic photosensitive component is produced in the same manner as in Example 1. Thus, a control electrophotographic photosensitive component without uneven shapes on its outer surface and without inorganic particles in its surface layer is produced. Using the produced control electrophotographic photosensitive component, the drive current value (current value B) of the rotary motor of the electrophotographic photosensitive component is obtained in the same manner as in Example 1.

[0303] Calculate the ratio of the drive current value (current value A) of the rotary motor of the electrophotographic photosensitive component obtained as described above to the drive current value (current value B) of the rotary motor of the electrophotographic photosensitive component obtained as described above. The obtained value of (current value A) / (current value B) is used as a relative torque value for comparison. The smaller the relative torque value, the smaller the friction between the electrophotographic photosensitive component and the cleaning blade.

[0304] [Evaluation of cleanliness]

[0305] While placing the modified equipment under low temperature and low humidity conditions of 15℃ and 10%RH, print images at a 5% print rate onto 500 sheets of A4-sized plain paper. Adjust the charging conditions to achieve a dark area potential of -500V, and adjust the exposure conditions to achieve an image exposure of 0.25μJ / cm². 2 Subsequently, halftone images obtained immediately after printing 10 solid white images followed by 10 solid black images were evaluated. Specifically, stripes in the halftone images caused by toner slippage due to poor cleaning were visually counted and evaluated according to the following criteria.

[0306] A: No stripes were observed in the image, and the image quality is good.

[0307] B: Causes very slight streaks.

[0308] C: Causes slight streaks.

[0309] D: Causes stripes on a portion of the image.

[0310] E: Causes stripes across the entire image.

[0311] The results are shown in Table 4.

[0312] [Evaluation of transferability]

[0313] While placing the modified equipment under low temperature and low humidity conditions of 15℃ and 10%RH, print images at a 5% print rate onto 500 sheets of A4-sized plain paper. Adjust the charging conditions to achieve a dark area potential of -500V, and adjust the exposure conditions to achieve an image exposure of 0.25μJ / cm². 2 In the evaluation, after printing 500 sheets, a solid black image was printed, and then the residual toner transferred from the photosensitive element during the formation of the solid black image was peeled off using transparent polyester adhesive tape.

[0314] The concentration difference was calculated by subtracting the concentration of the sample with adhesive tape only from the concentration of the sample with the peeled adhesive tape adhered to the paper. Concentration was measured at five locations, and the arithmetic mean of the results was calculated. Transferability was then evaluated based on the concentration difference (defined as residual transfer concentration) according to the following criteria. Concentration was measured using an X-RITE color reflectance aluminometer (X-Rite 500 series, manufactured by X-Rite Inc.).

[0315] (Evaluation Criteria)

[0316] A: The residual concentration of the transfer is less than 0.2.

[0317] B: The residual concentration of the transfer is above 0.2 and less than 0.5.

[0318] C: The residual concentration of the transfer is above 0.5 and less than 1.0.

[0319] D: The residual concentration of the transfer is above 1.0.

[0320] The results are shown in Table 4.

[0321] [Table 4]

[0322]

[0323] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims should be accorded the broadest interpretation, thereby covering all such modifications and equivalent structures and functions.

Claims

1. An electrophotographic photosensitive component, comprising, in sequence: Support body Photosensitive layer, and Surface layer, characterized in that The outer surface of the electrophotographic photosensitive component exhibits a wrinkled shape due to its uneven texture. When an observation area with a square side length of 200 μm is set at any position on the outer surface, a line passing through the center point of the observation area and parallel to the circumferential direction of the electrophotographic photosensitive element is defined as reference line L1, and 1,799 reference lines obtained by rotating reference line L1 around the center point at 0.1° are defined as reference lines L2 to L1,800 respectively. The baselines L1 to L1,800 intersect with the ridge line of the protrusion of the concave-convex shape at multiple locations, and The intersection angles between each of the baselines L1 to L1,800 and the edge have different values ​​at at least two locations selected from the plurality of locations. The surface layer comprises adhesive resin and inorganic particles, and At least a portion of the inorganic particles are exposed in the recesses of the uneven shape, wherein When a two-dimensional power spectrum F(r,θ) with frequency component r and angle component θ is obtained by frequency analysis of the height information of the concave-convex shape in the observation area, the one-dimensional radial distribution function p(r) obtained by integrating the two-dimensional power spectrum F(r,θ) along the θ direction has at least one maximum value, and When the angular distribution q(θ) is calculated from the two-dimensional power spectrum F(r,θ) at the frequency rp where the one-dimensional radial distribution function p(r) has the maximum value, the power value varies by less than 15% over the entire θ range.

2. The electrophotographic photosensitive component according to claim 1, wherein... The frequency rp is 0.05 to 0.17 μm. -1 .

3. The electrophotographic photosensitive component according to claim 1 or 2, wherein... The depth of the uneven shape is less than 1.0 μm.

4. The electrophotographic photosensitive component according to claim 1 or 2, wherein... The volume average particle size of the inorganic particles is 50 to 550 nm.

5. The electrophotographic photosensitive component according to claim 1 or 2, wherein... When the outer surface is viewed from above, the total area of ​​the exposed portion of the inorganic particles in the recess is defined as S1, and the total area of ​​the recess excluding the exposed portion of the inorganic particles is defined as S2, with S1 / (S1+S2) ranging from 0.20 to 0.

80.

6. The electrophotographic photosensitive component according to claim 1 or 2, wherein... The inorganic particles have a hydrophobic surface.

7. A processing box, characterized in that, It includes: Electrophotographic photosensitive component according to any one of claims 1 to 6; and Select at least one unit from the group consisting of a charging unit, a developing unit, and a cleaning unit. The processing box integrally supports the electrophotographic photosensitive component and the at least one unit, and is detachably mounted to the main body of the electrophotographic device.

8. An electrophotographic device, characterized in that, It includes: Electrophotographic photosensitive component according to any one of claims 1 to 6, Charging unit, Exposure unit, Developing unit, and Transfer unit.

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