Belt for electrophotography and electrophotographic image forming apparatus

Abstract

To provide a belt for electrophotography that is continuously excellent in toner cleaning performance and excellent in sensing characteristics.SOLUTION: A belt for electrophotography has an endless shape, and a plurality of grooves extending in a circumferential direction of the belt for electrophotography are provided in an outer surface of the belt for electrophotography. The outer surface comprises a first area in which the number of the grooves is n at least in a direction orthogonal to the circumferential direction of the belt for electrophotography, and a second area in which the number of the grooves is larger than n at least in the direction orthogonal to the circumferential direction of the belt for electrophotography. The grooves present in the second area include first grooves whose width is gradually reduced toward a first circumferential direction of the belt for electrophotography, and second grooves adjacent to the first groove and whose width is gradually reduced toward a second circumferential direction opposite to the first circumferential direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an electrophotographic belt such as a conveyance transfer belt or an intermediate transfer belt used in an electrophotographic image forming apparatus such as a copying machine or a printer, and an electrophotographic image forming apparatus.

Background Art

[0002] In an electrophotographic image forming apparatus, for example, an electrophotographic belt is used as an intermediate transfer belt that temporarily holds a toner image. Then, the residual transferred toner on the electrophotographic belt is cleaned using a cleaning blade made of an elastic member such as urethane rubber. In response to the increasing demand for higher image quality in recent electrophotographic image forming apparatuses, an electrophotographic belt showing stable cleaning characteristics has been demanded.

[0003] Patent Document 1 discloses a technique for suppressing wear between a belt and a cleaning blade and stably removing residual transferred toner over a long period by providing a plurality of fine grooves extending in the circumferential direction on the outer surface of an electrophotographic belt. The belt is composed of a first region in which the number of grooves in a direction orthogonal to the belt circumferential direction is n, and a second region in which the number of grooves is more than n.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] According to the inventors' investigations, the following has been confirmed regarding the electrophotographic belt described in Patent Document 1: Wear of the contact portion of the cleaning blade with the electrophotographic belt can be effectively suppressed, and as a result, residual toner is reliably removed from the outer surface, which is the toner image carrying surface, even after long-term use. However, in the course of this investigation, as shown in Figure 4, it was found that as the number of grooves in the direction perpendicular to the circumferential direction increases, the amount of specularly reflected light from the second region may decrease significantly.

[0006] In electrophotographic image forming apparatuses capable of forming color images, the following control may be performed to achieve high color reproducibility. Specifically, a color shift correction toner image (hereinafter also simply referred to as the "correction toner image") is formed on the intermediate transfer belt, and the correction toner image is detected by an optical sensor. Based on the detection result, control is performed to correct the color shift. The optical sensor detects the correction toner image using the difference (contrast) between the amount of reflected light from the area where the correction toner image is not formed and the amount of reflected light from the area where the correction toner image is formed. Therefore, in the electrophotographic belt according to the invention described in Patent Document 1, if the amount of specular reflected light from the second region decreases, the contrast in the second region decreases compared to the contrast in the first region. As a result, it may become impossible to accurately detect the correction toner image in the second region. One aspect of this disclosure is to provide an electrophotographic belt having two regions (a first region and a second region) with different numbers of grooves in the circumferential direction, and capable of ensuring a sufficient amount of specularly reflected light from the second region, which has a larger number of grooves. Another aspect of this disclosure is to provide an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images. [Means for solving the problem]

[0007] According to one aspect of this disclosure, An electrophotographic belt having an endless shape, Multiple grooves extending in the circumferential direction of the electrophotographic belt are provided on the outer surface of the electrophotographic belt. The outer surface shall be at least, A first region in which the number of grooves in a direction perpendicular to the circumferential direction of the electrophotographic belt is n, It consists of a second region in which the number of grooves in a direction perpendicular to the circumferential direction of the electrophotographic belt is greater than n, The groove in the second region is The electrophotographic belt has a first groove whose width gradually decreases in the first circumferential direction, An electrophotographic belt (where n is an integer of 1 or more) is provided, which includes a second groove adjacent to the first groove and whose width gradually decreases toward a second circumferential direction opposite to the first circumferential direction. According to another aspect of the present disclosure, an electrophotographic image forming apparatus is provided, comprising an endless intermediate transfer belt and a cleaning member in contact with the outer circumferential surface of the intermediate transfer belt, wherein the intermediate transfer belt is the electrophotographic belt described above. [Effects of the Invention]

[0008] According to one aspect of the present disclosure, an electrophotographic belt can be obtained having two regions (a first region and a second region) with different numbers of grooves in a direction perpendicular to the circumferential direction, wherein the amount of specularly reflected light from the second region, which has more grooves than the first region, can be secured. According to another aspect of the present disclosure, an electrophotographic image forming apparatus can be obtained that can stably form high-quality electrophotographic images. [Brief explanation of the drawing]

[0009] [Figure 1] (a) is a schematic diagram showing the surface configuration of an electrophotographic belt according to the present disclosure, and (b) is a partially enlarged view illustrating the state of grooves in the second region. [Figure 2] A schematic diagram showing a cross-section in a direction perpendicular to the circumferential direction in a first region of the electrophotographic belt based on this disclosure. [Figure 3]Schematic diagram showing a cross-section in a direction orthogonal to the circumferential direction in the second region of the electrophotographic belt according to the present disclosure. [Figure 4] Explanatory diagram of the specular reflection sensor output with respect to the number of grooves per unit length in the direction orthogonal to the circumferential direction. [Figure 5] Explanatory diagram of the reflection state of light from the belt surface having grooves. [Figure 6] Schematic diagram showing an example of the configuration of an intermediate transfer type electrophotographic image forming apparatus. [Figure 7] Schematic diagram showing an example of the configuration of the density detection sensor. [Figure 8] Schematic diagram showing an example of the density detection sensor differential output. [Figure 9] (a) is an explanatory diagram of stretch blow molding used in the manufacture of the electrophotographic belt, (b) is an explanatory diagram of an imprint processing apparatus used for forming grooves, and (c) is a cross-sectional view in a direction orthogonal to the circumferential direction of one aspect of the electrophotographic belt. [Figure 10] Schematic diagram showing an example of the convex cross-sectional shape of the cylindrical mold. [Figure 11] Explanatory diagram of the groove shape in the second region of Example 1. [Figure 12] Explanatory diagram of the sensing evaluation result of the belt of Example 1. [Figure 13] Explanatory diagram of the groove shape in the second region of Comparative Example 1. [[ID=3,1]] [Figure 14] Explanatory diagram of the sensing evaluation result of the belt of Comparative Example 1.

Modes for Carrying Out the Invention

[0010] The electrophotographic belt having an endless shape according to the present disclosure has a plurality of grooves extending in the circumferential direction of the electrophotographic belt provided on its outer surface. The outer surface has a first region where the number of the grooves in the direction orthogonal to the circumferential direction of the electrophotographic belt is n, and a second region where the number of the grooves in the direction orthogonal to the circumferential direction of the electrophotographic belt is more than n. In such a configuration, the amount of specularly reflected light from the second region with a relatively large number of grooves is smaller than the amount of specularly reflected light from the first region. FIG. 5 is an enlarged cross-sectional view in the direction orthogonal to the circumferential direction of the electrophotographic belt 500 having grooves extending in the circumferential direction on its outer surface. Of the light irradiated on the outer peripheral surface of the electrophotographic belt 500, the light (λ1) incident on the land portion 503 adjacent to the groove 501 is specularly reflected, but the light (λ2) incident on the bottom of the groove 501 is reflected, for example, by the side surface of the groove 501, resulting in a decrease in the amount of specularly reflected light. As a result, it is considered that the amount of specularly reflected light from the second region with a relatively large number of grooves is reduced compared to the amount of specularly reflected light from the first region.

[0011] Therefore, the inventor has studied to reduce the difference between the amount of specularly reflected light in the second region and the amount of specularly reflected light in the first region. As a result, the grooves in the second region are a first groove whose width gradually decreases toward a first circumferential direction of the belt, and a second groove adjacent to the first groove and having a width that gradually decreases toward a second circumferential direction opposite to the first circumferential direction It has been found that it is effective to adjust the widths of the grooves adjacent to each other in the second region so as to include them. In other words, the amount of specularly reflected light from each region depends on the width of each groove, and the specularly reflected light decreases as the groove width is relatively larger. Therefore, for the first groove in the second region, its width is shaped to gradually decrease toward one direction in the circumferential direction of the belt (hereinafter also referred to as "circumferential direction A2"). Furthermore, for at least one of the two grooves adjacent to the first groove, the width of the second groove is shaped to gradually decrease toward the direction opposite to circumferential direction A2 (hereinafter also referred to as "circumferential direction A1"). More preferably, the degree of decrease of the first groove toward circumferential direction A2 and the degree of decrease of the second groove toward circumferential direction A1 are complementary. This makes it possible to minimize the decrease in specularly reflected light in the second region due to the relatively larger number of grooves compared to the first region.

[0012] The following describes in detail an electrophotographic belt relating to one aspect of this disclosure. However, this disclosure is not limited to the following aspect. Figure 1(a) is a schematic diagram illustrating the outer surface of an electrophotographic belt (hereinafter sometimes simply referred to as "belt") 5 according to one aspect of the present disclosure, and Figure 1(b) is a partially enlarged view of area X in Figure 1(a).

[0013] <Electrophotographic belt> The belt 5 has an endless shape, and the outer surface of the belt 5 is provided with a plurality of grooves 200 extending in the circumferential direction of the electrophotographic belt. An example of an electrophotographic belt having an endless shape is an intermediate transfer belt. The outer surface of the belt 5 has a first region 300 in which the number of grooves in the direction perpendicular to the circumferential direction is n, and a second region 301 in which the number of grooves in the direction perpendicular to the circumferential direction is greater than n. Here, n is an integer of 1 or more, and the number is not particularly limited as long as the outer surface can be stably cleaned by a cleaning member. As an example, in the first region, it is preferable that the number of grooves per 1 mm of width in the direction perpendicular to the circumferential direction of the electrophotographic belt is 8 to 500. Specifically, for example, if the total width in the direction perpendicular to the circumferential direction of the electrophotographic belt is 244 mm, it is preferable that the number of grooves n in the first region is n = 1952 to 122000. Also, if the total width is 360 mm, it is preferable that n = 2880 to 180000. By setting the number of grooves in the first region to the range described above, the area of ​​the cleaning member (not shown) that comes into contact with the portion where grooves 200 are not provided is reduced, thereby reducing the frictional force generated between the cleaning member and the electrophotographic belt 5. In addition, it is possible to suppress the decrease in specular reflected light from the second region caused by having too many grooves in the second region.

[0014] The first region 300 includes a groove 200-1. The width of the groove 200-1 is preferably constant. However, "constant" here means that the unavoidable dimensional variations in forming the groove are constant. On the other hand, the second region 301 includes a first groove 200-2 whose width gradually decreases toward the first circumferential direction A1 of the belt, and a second groove 200-3 adjacent to the first groove 200-2, whose width gradually decreases toward the second circumferential direction A2 opposite to the circumferential direction A1. The first groove 200-2 and the second groove 200-3 are arranged alternately in a direction perpendicular to the circumferential direction of the belt. In the second region, which has more grooves than the first region 300, the widths of adjacent grooves are changed to be complementary toward one circumferential direction, for example, the first circumferential direction A1. In this way, the decrease in specular reflected light in the second region caused by the increase in the number of grooves can be suppressed more reliably. The degree of gradual reduction in the width of grooves 200-2 and 200-3 in the second region 301 is not particularly limited. However, in order to stably maintain good cleaning performance in the second region, it is preferable that the width of the second region decreases at a constant rate from one end to the other in the circumferential direction of the belt.

[0015] The number of grooves in the second region is preferably 2n-10 or more and 2n+10 or less. By setting the number of grooves in the second region to 2n-10 or more, it is possible to stably cause changes in the position of the contact portion of the cleaning member at the boundary between the first and second regions. Furthermore, by setting the number of grooves in the second region to 2n+10 or less, it is possible to more stably transfer the toner in the secondary stage even if the toner is first transferred onto the grooves.

[0016] Figure 2 shows a cross-sectional view of the belt 101 in the first region in a direction perpendicular to the circumferential direction. W1 represents the width of the groove, H1 represents the depth of the groove, and P1 represents the spacing between the grooves. Figure 3 shows a cross-sectional view of the belt 101 in the second region in a direction perpendicular to the circumferential direction. In the second region, first grooves 200-2, whose width gradually decreases toward the first circumferential direction A1 of the belt 101, and second grooves 200-3, adjacent to the first grooves 200-2 and whose width gradually decreases toward the second circumferential direction A2 opposite to the circumferential direction A1, are arranged alternately. Therefore, depending on the observation position, there are places where narrow grooves and wide grooves are present alternately. W2a and W2b represent the width of each groove, H2a and H2b represent the depth of each groove, and P2a and P2b represent the spacing between each groove. Also, d represents the distance between the centers of adjacent grooves.

[0017] Regarding the spacing between adjacent grooves (P1, P2a, P2b, d), there are no particular restrictions as long as it is within the range of the number of grooves mentioned above, but it is preferable that they be approximately uniform from the viewpoint of toner cleaning. For example, if the length of the belt in the direction perpendicular to the circumferential direction is 244 mm, it is preferable that P1 be between 2 μm and 122 μm. By setting P1 to 122 μm or less, 2000 grooves can be formed in the first region, enabling better cleaning. Also, by setting P1 to 2.0 μm or more, it is possible to suppress the excessive increase in the number of grooves formed in the second region.

[0018] The groove widths (W1, W2a, W2b) are preferably 0.10 μm to 3.00 μm, and more preferably 0.20 μm to 2.00 μm. A groove width of 0.10 μm or more can more reliably suppress the disappearance of the grooves due to wear on the outer surface associated with the use of electrophotographic belts. Furthermore, a groove width of 3.00 μm or less can effectively suppress the decrease in the secondary transferability of toner when toner is primarily transferred onto the grooves.

[0019] The groove depths (H1, H2a, H2b) are preferably 0.10 μm or more and less than 5.00 μm, and more preferably 0.20 μm or more and less than 2.00 μm. A groove depth of 0.10 μm or more can more reliably suppress the disappearance of the grooves due to wear on the outer surface associated with the use of electrophotographic belts. Furthermore, by setting the groove depth to 5.00 μm or less, vignetting of reflected light from the bottom of the grooves due to the groove walls can be reduced, contributing to further suppression of the decrease in specular reflected light caused by the grooves. In addition, for grooves 200-2 and 200-3 in the second region, it is preferable that the groove depth gradually decreases as the groove width gradually decreases. The shallower the groove depth, the less vignetting of reflected light from the bottom of the grooves due to the groove walls can be reduced, and the reduction in specular reflected light can be suppressed. Therefore, by making the depth of grooves 200-2 and 200-3 shallower as the groove width gradually decreases, the decrease in specular reflected light in the second region caused by the increase in the number of grooves can be better suppressed.

[0020] In the belt according to this disclosure, it is preferable that the direction of extension of the groove 200 is non-parallel to the circumferential direction of the belt. Specifically, it is preferable that the narrow angle θ (see Figure 1(c)) that the groove 200-1 in the first region makes with the straight line A1-A2 parallel to the circumferential direction is not 0° (θ≠0°) and is greater than -3° and less than +3°. θ being 0° means that the groove 200-1 extends parallel to the circumferential direction. By θ not being 0°, the contact position of the cleaning member with the outer surface of the electrophotographic belt is not fixed, and wear on only a specific part can be suppressed. Furthermore, assuming that θ is not 0°, setting θ to greater than -3° and less than +3° can suppress excessive friction between the cleaning member and the electrophotographic belt. In other words, the preferred range for θ is -3°<θ<0° and 0°<θ<+3°.

[0021] One embodiment of an electrophotographic belt is shown, for example, in Figure 9(c), which shows a cross-section in a direction perpendicular to the circumferential direction of the belt in the first region, The material may have an endless base layer 909 and a surface layer 907 provided on its outer circumferential surface, with a groove 200-1 formed on the surface of the surface layer opposite to the surface facing the base layer. Furthermore, a configuration can be provided between the base layer 909 and the surface layer 907, which is not shown. As a method for forming the base layer, known methods using known thermoplastic resins or thermosetting resins can be used. Specific examples of molding methods using thermoplastic resins include the following: A method for obtaining an endless belt-shaped electrophotographic belt by pelletizing a resin composition and molding it using known molding methods such as continuous melt extrusion molding, injection molding, stretch blow molding, or inflation molding.

[0022] The surface layer can be formed using known methods such as dip coating, spray coating, flow coating, shower coating, roll coating, spin coating, and ring coating. For forming grooves, known processing methods such as cutting, etching, and imprinting can be used. From the viewpoint of groove reproducibility and processing cost, imprinting is preferred.

[0023] Then, the groove 200 in the second region is as shown in Figure 1(b), A groove 200-2 whose width gradually decreases toward the first circumferential direction A1, A groove 200-3 whose width gradually decreases toward the second circumferential direction A2 and A method for manufacturing electrophotographic belts, including the following, will be explained using an example that employs an imprinting process. Furthermore, the electrophotographic belts relating to this disclosure are not limited to those manufactured by this method.

[0024] The imprinting method according to this disclosure includes the step of pressing a mold having a protrusion in a shape corresponding to the groove to be formed against the surface to be processed. Specifically, for example, as shown in Figure 9(b), a cured film of a curable resin composition is formed on the outer circumferential surface of a substrate having an endless shape. Then, the substrate 901 having the cured film is held on the outer circumferential surface of a cylindrical holding mold 900. On the other hand, a cylindrical mold is prepared in which protrusions corresponding to the width, depth, and pitch of the groove 200-1 to be formed in the first region are provided on the outer circumferential surface in a spiral shape over the entire circumference at a predetermined angle of inclination with respect to the circumferential direction so as to correspond to the narrow angle θ. Here, the shape of the protrusions is, for example, as shown in Figure 10, a trapezoidal shape in a cross section in a direction perpendicular to the direction in which the protrusions extend at a predetermined angle in the circumferential direction of the cylindrical mold.

[0025] Next, the cylindrical mold 905 is positioned relative to the holding mold 900 that holds the substrate 901 having the cured film, such that the rotation axes of the holding mold 900 and the cylindrical mold 905 are parallel, and the tip of the protrusion of the cylindrical mold 905 is in contact with the outer surface of the cured film. Then, while rotating both the holding mold and the cylindrical mold 905 at a predetermined speed, the cylindrical mold 905 is pressed against the holding mold, gradually increasing the pressure at a predetermined rate. Once the pressure reaches a predetermined value, that pressure is maintained, and once the initial contact position of the hardened film on the holding mold with the mold has completed one rotation, the pressing force of the mold against the holding mold is gradually decreased at a predetermined rate, and the cylindrical mold 905 is released. In this way, the convex shape of the surface of the cylindrical mold 905 is transferred to the hardened film. Because the protrusions of the cylindrical mold 905 are formed in a spiral shape in the circumferential direction, the start and end points of the transferred grooves do not coincide. Furthermore, since mold release begins when the holding mold has completed one rotation, the end point of the grooves in the circumferential direction of the cured film is located downstream in the rotational direction from the start point of the grooves. As a result, the surface of the cured film is formed with a first region where there are n grooves in a direction perpendicular to the circumferential direction, and a second region where there are more than n grooves in a direction perpendicular to the circumferential direction.

[0026] The thickness of the electrophotographic belt is preferably 10 μm to 500 μm, and particularly preferably 30 μm to 150 μm. In addition to being used as a belt, the electrophotographic belt of this disclosure may also be used by winding it around or covering drums or rolls used as electrophotographic components.

[0027] <Electrophotographic image forming apparatus> Figure 6 shows an example of an image forming apparatus configured as an electrophotographic apparatus, which incorporates an electrophotographic belt based on the present disclosure as an intermediate transfer body. This image forming apparatus performs color image formation on a recording medium S such as paper supplied from a paper feed cassette 20 using four toners represented by C, M, Y, and K, respectively, with image forming stations for each color arranged substantially horizontally. Each of these image forming stations is equipped with a photosensitive drum 1c, 1m, 1y, and 1k. Here, by adding the subscripts "c," "m," "y," or "k" to the reference numerals, it is indicated which color image forming station the component with the reference numeral belongs to: "cyan," "magenta," "yellow," or "black." This image forming apparatus is equipped with a laser scanner 3, which is a laser optical unit, from which laser beams 3c, 3m, 3y, and 3k corresponding to the image signals of each color are emitted toward the respective photosensitive drums 1c, 1m, 1y, and 1k.

[0028] Since all image forming stations have the same structure, the image forming station for K color (black) will be described here. Surrounding the photosensitive drum 1k are a conductive roller 2k, which is a contact charging device, a developer unit 4k, a conductive roller 8k, which is a primary transfer roller, and a toner recovery blade 14k, which is used to clean the photosensitive drum 1k. The developer unit 4k is equipped with a developer roller 41k, which is a developer carrier for developing the latent image on the photosensitive drum 1k, a developer container 42k that holds the toner supplied to the developer roller 41k, and a developer blade 43k that regulates the amount of toner on the developer roller 41 and applies an electric charge.

[0029] The electrophotographic belt 5 is configured as an endless belt and is provided in common to each color image forming station. It is stretched over the secondary transfer opposing roller 92, tension roller 6, and drive roller 7, and is rotated in the direction of the arrow shown by the drive roller 7. In the section between the tension roller 6 and the drive roller 7, the electrophotographic belt 5 sequentially contacts the surfaces of the photosensitive drums 1y, 1m, 1c, and 1k, and is pressurized towards the photosensitive drums 1y, 1m, 1c, and 1k by the primary transfer rollers 8y, 8m, 8c, and 8k, respectively. As a result, the toner images formed on the surfaces of the photosensitive drums 1y, 1m, 1c, and 1k are transferred to the surface of the electrophotographic belt 5, which is an intermediate transfer body.

[0030] A secondary transfer roller 9 is provided opposite the opposing roller 92, and the electrophotographic belt 5 is pressed toward the opposing roller 92 by the secondary transfer roller 9. A secondary transfer voltage is applied to the secondary transfer roller 9 from the power supply via the current detection circuit 10. The secondary transfer section is formed by the secondary transfer roller 9 and the opposing roller 92. The recording medium S passes through the feeding roller 12 and the transport roller 13, and at the position of the opposing roller 92, it passes through the nip between the electrophotographic belt 5 and the secondary transfer roller 9, thereby transferring the toner image held on the outer surface of the electrophotographic belt 5. As a result, an image is formed on the surface of the recording medium S. The recording medium S, on which the toner image has been transferred, passes through the fuser 15, which consists of a pair of rollers, a heating roller 151 and a pressure roller 152, thereby fixing the image, and is discharged into the output tray 21.

[0031] A cleaning blade 11 is provided at the position of the tension roller 6, which contacts the outer surface of the electrophotographic belt 5. Toner that remains on the outer surface of the electrophotographic belt 5 without being transferred to the recording medium S is scraped off and removed by the cleaning blade 11. The cleaning blade 11 is a component that extends in a direction substantially perpendicular to the direction of movement of the electrophotographic belt 5. There are no particular restrictions on the cleaning blade 11 as long as it is suitable for toner cleaning, but examples include urethane rubber, acrylic rubber, nitrile rubber, and EPDM rubber, and urethane rubber is preferred from the viewpoint of toner cleaning.

[0032] The color of printed materials changes depending on the operating environment and other conditions of the electrophotographic image forming apparatus. Therefore, it is necessary to measure the density as needed and provide feedback to the control mechanism inside the unit. The toner image for density correction is transferred to the surface of the electrophotographic belt 5 and then transported to the position of the drive roller 7 as the electrophotographic belt 5 rotates. The toner density is detected by a density detection sensor 160 located on the opposite side of the electrophotographic belt 5 from the drive roller 7.

[0033] Figure 7 is a schematic diagram of the density detection sensor 160. The density detection sensor 160 consists of a light-emitting element 161, a diffuse reflection light-receiving element 162, and a specular reflection light-receiving element 163. The light-emitting element 161 emits infrared light, and this light is reflected from the surface of the toner image T. The diffuse reflection light-receiving element 162 is positioned to receive reflected light from directions other than the specular reflection direction relative to the position of the toner image T, and detects the diffusely reflected light at the position of the toner image T. The specular reflection light-receiving element 163 is positioned to receive reflected light in the specular reflection direction relative to the toner image T, and detects the specular reflected light at the position of the toner image T. The detected voltage values ​​are called the diffuse reflection output and specular reflection output, respectively.

[0034] Figure 8(a) is a schematic diagram illustrating the specular reflection output fluctuation 401, diffuse reflection output fluctuation 402, and sensor output fluctuation 403 calculated from them, with respect to toner density. When the amount of toner (toner density) is small, the specular reflection output is large because a large amount of reflection is detected from the smooth mirror-like surface of the electrophotographic belt 5. As the amount of toner (toner density) increases, the specular reflection output decreases. When the number of toner layers is one or more, the specular reflection component from the surface of the electrophotographic belt 5 is almost eliminated, but since the specular reflection output includes both the output from the specular reflection component and the output from the diffuse reflection component, the specular reflection output does not decrease monotonically in the high density region. On the other hand, the diffuse reflection output increases monotonically with respect to the amount of toner, but the amount of change (increase) is small compared to the amount of change (decrease) in the specular reflection output. By removing the output from the diffuse reflection component obtained from the diffuse reflection output from the specular reflection output, a sensor output fluctuation 403 (hereinafter also referred to as sensor output) correlated with toner density can be obtained.

[0035] Figure 8(b) is an overview diagram illustrating the background output at multiple locations on the surface of the electrophotographic belt 5 and the patch output at those locations. Background output refers to the sensor output when there is no toner, and patch output refers to the sensor output when there is toner. As shown in Figure 8(b), the background output 404 fluctuates depending on the position of the electrophotographic belt 5. Specifically, the specular reflection output changes because the reflectivity and surface shape differ locally depending on the position on the surface of the electrophotographic belt 5, and as a result, the background output 404, which is the sensor output 403, fluctuates. The patch outputs 405 all detect toner images formed with the same halftone density, but like the background output 404, they fluctuate depending on the position on the surface of the electrophotographic belt 5. In other words, even if the toner density is the same, the patch output 405 fluctuates according to the changes in the state of the background (belt surface). Therefore, if image density control is performed based on the patch output 405 itself, which does not accurately reflect the toner density, the accuracy of image density control will decrease. To avoid such a decrease in accuracy as much as possible, it is preferable that the specular reflection output, which is the main output for the substrate, be as uniform as possible regardless of its position on the surface of the electrophotographic belt 5. [Examples]

[0036] The present disclosure will be specifically explained below with reference to examples and comparative examples, but the present disclosure is not limited to the configurations embodied in the examples. The characteristics and performance evaluation methods for the electrophotographic belts fabricated in the examples and comparative examples are as follows: [Evaluation 1] to [Evaluation 5].

[0037] [Evaluation 1] Evaluation of the number of grooves on the surface of the electrophotographic belt and the circumferential length of the second region. The surface grooves on the electrophotographic belt were observed at 10x magnification across the entire belt using a digital microscope (product name: VHX-500, manufactured by Keyence Corporation). The presence and number of first and second regions were confirmed, and the length of the second region was also determined. Next, the number of grooves in the direction perpendicular to the circumferential direction in the first and second regions was counted. For regions with a length of 100 mm or less, the groove count was taken at the center of the region. For regions with a length exceeding 100 mm, measurements were taken at one point every 100 mm, and the arithmetic mean was calculated.

[0038] [Evaluation 2] Evaluation of groove shape on the surface of electrophotographic belts The surface of the electrophotographic belt was observed at 50x magnification using a scanning white light interference microscope (product name: Vert Scan, manufactured by Ryoka Systems Co., Ltd.) to confirm the width and depth of the grooves. For measuring the groove shape, three points were selected in the first and second regions: the midpoint in the direction perpendicular to the circumferential direction of the belt (width direction), and 100 mm from that midpoint to both ends. In addition, five points were evaluated in the circumferential direction at intervals of 1 / 5 of the circumferential length in each of the first and second regions.

[0039] Because the observation field of view when using a 50x lens is narrow (94.1 μm × 70.6 μm), images were acquired from multiple fields of view using the image stitching function. From the cross-sectional shape profile, more than 10 groove shapes were measured per measurement point, and the arithmetic mean was used as the representative value for evaluation. In the first region, all grooves within the observation field of view were evaluated. In the second region, the odd-numbered grooves and even-numbered grooves counting from the left edge of the observation field of view were classified into groove A and groove B for evaluation.

[0040] [Evaluation 3] Sensing evaluation (calculation of the rate of change of specular reflection output) Using the electrophotographic image forming apparatus shown in Figure 6, an electrophotographic belt was mounted as an intermediate transfer body. The specular reflection output per rotation of the electrophotographic belt was measured in 1 mm increments, and the arithmetic mean Vave, maximum value Vmax, minimum value Vmin, and deflection rate were evaluated using the following formula (1). The density detection sensor was positioned at ±100 mm from the center in the width direction of the electrophotographic belt. Furthermore, since the specular reflection output changes depending on the conditions of the grooves applied to the surface of the electrophotographic belt, in this evaluation, the light intensity output was adjusted so that the specular reflection output in the first region was 3.0 V. Runout = (Vmax - Vmin) / Vave Equation (1)

[0041] [Evaluation 4] Evaluation of toner cleaning performance Using the electrophotographic image forming apparatus shown in Figure 6, an electrophotographic belt was attached as an intermediate transfer body, and blade cleaning was performed while printing an image to evaluate the toner cleaning performance. This evaluation was conducted under conditions of 15°C and 10% relative humidity, using OCE Corporation's Extra (basis weight 80g / m²) as the recording medium S. 2 Using JIS A4 size paper, the printer was subjected to intermittent printing of two sheets at a time, with a maximum of 200,000 sheets fed through until a toner cleaning failure occurred. The printer was then evaluated based on whether or not toner leaked through the cleaning blade.

[0042] Specifically, first, with the secondary transfer voltage turned off (0V), a red image (Y toner and M toner) was recorded across the entire A4 size by irradiating the photosensitive drum at 1y and 1m with laser beams at 3y and 3m. After that, the secondary transfer voltage was set to the appropriate value, and three blank sheets of paper were fed through continuously. Since no secondary transfer voltage is applied, the Y toner and M toner transferred from the photosensitive drums 1y and 1m to the entire surface of the electrophotographic belt 5 enter the cleaning blade 11 with almost no transfer to the recording medium S in the secondary transfer section. If these toners are removed from the electrophotographic belt, the next three sheets of paper passed through will be output as completely blank. However, if they are not removed, the remaining toner that has passed through the cleaning blade 11 will then be transferred to the recording medium S in the secondary transfer section. In other words, it will be transferred onto the blank paper and output as a toner cleaning defect image on the recording medium S.

[0043] The above evaluations were conducted at the points of 50,000 sheets, 100,000 sheets, 150,000 sheets, and 200,000 sheets being processed. Based on these evaluation results, the electrophotographic belts were ranked according to the following criteria. A toner cleaning failure was determined to have occurred when streaks parallel to the transport direction of the recording medium S were visually confirmed to be present on the white areas of the recording medium S. Rank A: No toner cleaning failures occurred during the 200,000-sheet paper feeding process. Rank B: A toner cleaning failure occurred during the 200,000-sheet paper feeding process. Rank C: A toner cleaning failure occurred during the 150,000-sheet paper feeding process. Rank D: A toner cleaning failure occurred during the 100,000-sheet paper feeding process. Rank E: A toner cleaning failure occurred during the 50,000-sheet paper feeding process.

[0044] [Evaluation 5] Evaluation of halftone image performance Using the electrophotographic image forming apparatus shown in Figure 6, an electrophotographic belt was mounted as an intermediate transfer medium to output a halftone red image (Y toner and M toner). Based on these evaluation results, the electrophotographic belts were ranked according to the following criteria. Rank A: No streaky unevenness in density is visible. Rank B: Slight streaky unevenness in density is visible. Rank C: Streaky unevenness in density is visible.

[0045] (Example 1) [Base layer manufacturing] First, a thermoplastic resin composition was prepared by hot-melt kneading the following base material in a ratio of PEN / PEEA / CB = 84 / 15 / 1 (mass ratio) using a twin-screw extruder (product name: TEX30α, manufactured by Japan Steel Works, Ltd.). The hot-melt kneading temperature was adjusted to be within the range of 260°C to 280°C, and the hot-melt kneading time was approximately 3 to 5 minutes. The obtained thermoplastic resin composition was pelletized and dried at a temperature of 140°C for 6 hours. Next, the dried pelletized thermoplastic resin composition was fed into an injection molding machine (product name: SE180D, manufactured by Sumitomo Heavy Industries, Ltd.). Then, with the cylinder temperature set to 295°C, a preform was produced by injection molding in a mold whose temperature was controlled to 30°C. The obtained preform had a test tube shape with an outer diameter of 50 mm, an inner diameter of 46 mm, and a length of 100 mm. ·Base material PEN: Polyethylene naphthalate (Product name: TN-8050SC, manufactured by Teijin Chemicals Ltd.) PEEA: Polyether ester amide (Product name: Perestat NC6321, manufactured by Sanyo Chemical Industries, Ltd.) CB: Carbon Black (Product Name: MA-100, manufactured by Mitsubishi Chemical Corporation)

[0046] Next, the preform described above is biaxially stretched using the biaxial stretching apparatus (stretch blow molding machine) shown in Figure 9(a). Before biaxial stretching, the preform 104 is placed in a heating device 107 equipped with non-contact heaters (not shown) for heating the outer and inner walls of the preform 104, and the heating device is used to heat the outer surface temperature of the preform to 150°C. Next, the heated preform 104 was placed in a blow mold 108, which was maintained at a mold temperature of 30°C, and stretched axially using a stretching rod 109. At the same time, air heated to 23°C was introduced into the preform from the blow air injection section 110 to stretch the preform 104 radially. In this way, a bottle-shaped molded product 112 was obtained. Next, the body of the obtained bottle-shaped molded product 112 was cut to obtain a seamless electrophotographic belt base layer. The thickness of this electrophotographic belt base layer was 70.2 μm, the circumference was 712.2 mm, and the width was 244.0 mm.

[0047] [Formulation of coating solution] The surface layer materials listed below were weighed in the ratio AN / PTFE / GF / SL / IRG = 66 / 20 / 1.0 / 12 / 1.0 (mass ratio on a solid content basis). The solution, which was roughly dispersed using all materials except SL, was subjected to the main dispersion treatment using a high-pressure emulsifier / disperser (product name NanoVeta, manufactured by Yoshida Machinery Industry Co., Ltd.) until the 50% average particle size of PTFE reached 200 nm. Furthermore, while stirring the SL, the solution after the main dispersion treatment of PTFE was added dropwise to obtain a coating solution for surface layer formation. The particle size of PTFE in the coating solution was measured using a concentrated particle size analyzer (product name FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.) based on dynamic light scattering (DLS) technology (ISO-DIS22412).

[0048] [Table 1]

[0049] [Formation of the surface layer] The base layer obtained by blow molding was fitted onto the outer circumference of a cylindrical mold (circumference 712 mm), the ends were sealed, and the mold was immersed in a container filled with the coating liquid (curable composition). Then, by pulling up the mold while maintaining a constant relative speed between the liquid level of the curable composition and the base layer, a coating film made of the coating liquid was formed on the surface of the base layer. The desired film thickness can be obtained by adjusting the pulling speed (relative speed between the liquid level of the curable composition and the base layer) and the solvent ratio of the curable composition. In this example, the pulling speed was set to 10-50 mm / second, and the film thickness of the surface layer was adjusted to 3 μm.

[0050] In this embodiment, the coating direction refers to the direction opposite to the direction in which the base layer is lifted. That is, the point where the base layer is first lifted from the coating solution is the upstream point. The base layer coated with the coating solution was removed from the cylindrical mold and dried for 1 minute in an environment of 23°C under exhaust. The drying temperature and drying time were adjusted as appropriate according to the solvent type, solvent ratio, and film thickness. After that, a UV irradiation machine (product name: UE06 / 81-3, manufactured by iGraphic Co., Ltd.) was used to obtain an integrated light dose of 600 mJ / cm². 2 The coating was cured by irradiating it with ultraviolet light until it reached a certain thickness. The thickness of the surface layer was measured by destructive testing, which involved cutting an electrophotographic belt prepared separately under the same conditions and observing the cross-section with an electron microscope (product name: XL30-SFEG, manufactured by FEI). The results of the destructive testing showed that the thickness of the surface layer was 3.0 μm.

[0051] [Formation of grooves] Using the imprint processing apparatus shown in Figure 9(b), grooves were formed in the cured film of the base layer 60, which held the cured coating film. The imprinting apparatus consists of a cylindrical mold 905 for creating grooves and a cylindrical belt holder 900. The cylindrical mold 905 can be pressed against the cylindrical belt holder 900 while keeping its axis parallel to the holder. At this time, the cylindrical mold 905 and the cylindrical belt holder 900 rotate synchronously without slipping.

[0052] The cylindrical mold 905 is made of carbon steel with electroless nickel plating, and has a diameter of 50 mm and a length of 250 mm. The surface of the cylindrical mold 905 has protrusions corresponding to the shape of the grooves, and these protrusions are formed in a spiral shape with an angle of 0.1° to the circumferential direction of the cylindrical mold 905. The cross-sectional shape of the protrusions corresponding to the grooves in the cylindrical mold 905 used in this embodiment, in the direction perpendicular to the circumferential direction, is a trapezoidal shape as shown in Figure 10, with dimensions of H=3.5 μm, Wb=2.0 μm, Wt=0.2 μm, and P=20 μm. A cartridge heater is embedded inside the cylindrical mold 905, allowing it to be heated.

[0053] A base layer with a coating was pre-fitted to the outer circumference of the cylindrical belt-holding mold 900 (circumference 712 mm). This was rotated together with the cylindrical mold 905 at a peripheral speed of 1 mm / sec (in opposite directions of rotation), and while maintaining the parallel axis lines of their respective bodies, the cylindrical mold 905, heated to 130°C, was brought into contact with the belt-holding mold, and the pressing force was increased at a rate of 1.0 kN / s up to 8.0 kN. The cylindrical belt-holding mold 900 and the cylindrical mold 905 continued to rotate while the pressing force of the cylindrical mold 905 was being increased. After that, the cylindrical belt-holding mold 900 and the cylindrical mold 905 were rotated while maintaining the pressing force at 8.0 kN.

[0054] Then, when the cylindrical belt holder 900 had completed one full rotation at the point where it first contacted the cylindrical mold 905, the pressure applied to the cylindrical mold 905 was reduced at a rate of 1.0 kN / s, and the cylindrical mold 905 was released. This transferred the pattern of the convex portion of the cylindrical mold 905 to the surface of the electrophotographic belt, forming grooves. Because the convex pattern of the cylindrical mold 905 was spiral in shape, the start and end points of the grooves did not connect after one full rotation, and a second region with more grooves than the first region was formed. The groove pattern of the electrophotographic belt obtained from the above process consisted of one first region and one second region, with 12,200 grooves in the first region, 24,401 grooves in the second region, and a circumferential length of 7.8 mm in the second region. The width and depth of the groove in the first region were as follows: W1 = 0.6 μm H1 = 0.6 μm P1 = 20 μm

[0055] In this example, observation of three fields of view was performed at each measurement point, and 14 grooves were evaluated. Figures 11(a) and 11(b) show the average groove widths (W2a, W2b) and average groove depths (H2a, H2b) of grooves A (corresponding to groove 200-3 in Figure 1) and B (corresponding to groove 200-2 in Figure 1) with respect to the belt circumferential direction in the second region. In Figures 11(a) and 11(b), the origin (0 mm) of the circumferential distance on the horizontal axis is the position furthest towards the A2 direction in the second region shown in Figure 1. The groove spacing was as follows. P2a = 20 μm P2b = 20 μm d = 10 μm

[0056] As shown in Figure 11(a), the groove width of groove B (corresponding to groove 200-2 in Figure 1) gradually decreased toward the belt circumferential direction A1. Also, as shown in Figure 11(b), the groove depth of groove B gradually decreased toward the belt circumferential direction A1. The above-mentioned changes in groove width and groove depth of groove B are due to the following two points. The cross-sectional shape of the cylindrical mold 905 in the direction perpendicular to the circumferential direction of the convex portion is substantially trapezoidal, as shown in Figure 10, and, Groove B is a groove formed during the process of increasing the pressure by a predetermined rate when transferring the pattern of the convex portion of the cylindrical mold 905 to the cured film by rotating the cylindrical mold 905 in the direction of A2. On the other hand, as shown in Figure 11(a), groove A (corresponding to groove 200-3 in Figure 1) had a gradually decreasing groove width towards the belt circumferential direction A2. Also, as shown in Figure 11(b), groove A had a gradually decreasing groove depth towards the belt circumferential direction A2. The above-mentioned changes in the width and depth of groove A are due to the following two points. The cross-sectional shape of the cylindrical mold 905 in the direction perpendicular to the circumferential direction of the convex portion is substantially trapezoidal, as shown in Figure 10. Groove A is a groove formed by reducing the pressure by a predetermined percentage during the process of transferring the pattern of the convex portion of the cylindrical mold 905 to the cured film by rotating the cylindrical mold 905 in the direction of A2 to form the second region.

[0057] When the electrophotographic belt was mounted on the electrophotographic image forming apparatus shown in Figure 6 and the specular reflection output was evaluated, the waveform shown in Figure 12 was obtained. Figure 12(a) is a chart showing the specular reflection output in the entire circumferential direction of the electrophotographic belt. Figure 12(b) is an enlarged chart extracted from the chart shown in Figure 12(a), focusing on the vicinity of the second region. As is clear from Figures 12(a) and (b), the electrophotographic belt according to this embodiment has equivalent specular reflection output in the first and second regions, and the deflection rate calculated using equation (1) was 3%.

[0058] Furthermore, the toner cleaning performance was evaluated. No toner cleaning defects occurred during the 200,000-sheet paper feeding process, and it was determined to be a rank A electrophotographic belt. The electrophotographic belt was mounted in the electrophotographic image forming apparatus shown in Figure 6, and its halftone image performance was evaluated. No streaky density variations caused by the groove pattern on the surface of the electrophotographic belt were observed, and it was determined to be an electrophotographic belt of rank A.

[0059] (Comparative Example 1) When forming grooves using an imprint processing device, With the cylindrical mold 905 and the cylindrical belt holding mold 900 stationary, pressurize the cylindrical mold 905 against the cylindrical belt holding mold 900 to 8.0 kN. While maintaining the pressurizing force at 8.0 kN, the cylindrical belt holding mold 900 and the cylindrical mold 905 are rotated. When the portion of the cylindrical belt holder 900 that began contacting the cylindrical mold 905 exceeded one full rotation of the cylindrical belt holder 900, the cylindrical belt holder 900 and the cylindrical mold 905 were stopped. Then, with the cylindrical mold 905 and the cylindrical belt holder 900 stationary, the pressure on the cylindrical mold 905 was reduced to 0 kN relative to the cylindrical belt holder 900. An electrophotographic belt was fabricated in the same manner as in Example 1, except for the differences described above.

[0060] Figures 13(a) and (b) show the average groove widths (W2a, W2b) and average groove depths (H2a, H2b) of grooves A and B, respectively, in the circumferential direction of the fabricated electrophotographic belt in the second region. As shown in Figures 13(a) and (b), the circumferential groove width and groove depth of adjacent grooves in the second region that are perpendicular to the circumferential direction (corresponding to grooves 200-2 and 200-3 in this disclosure) were constant.

[0061] The fabricated electrophotographic belt was mounted on the electrophotographic image forming apparatus shown in Figure 6, and the specular reflection output in the circumferential direction was observed. The results are shown in Figure 14(a). Figure 14(b) is an enlarged chart extracted from the chart shown in Figure 14(a), showing the vicinity of the second region. As shown in Figures 14(a) and (b), the specular reflection output from the second region was significantly reduced compared to the specular reflection output from the first region, and the deflection rate calculated using the above formula (1) was 52%. Furthermore, the toner cleaning performance was evaluated in the same manner as in Example 1. No toner cleaning defects occurred during the 200,000-sheet paper feeding process, and it was determined to be a rank A electrophotographic belt. In addition, the halftone image performance was evaluated in the same manner as in Example 1. No streaky density unevenness caused by the groove pattern on the surface of the electrophotographic belt was observed, and it was determined to be a rank A electrophotographic belt.

[0062] (Examples 2-3) An electrophotographic belt was fabricated in the same manner as in Example 1, except that the spacing (P) of the convex patterns on the cylindrical mold 905 for groove formation was set to 100 μm and 3.0 μm, respectively, and then subjected to evaluation.

[0063] (Examples 4-6) An electrophotographic belt was manufactured in the same manner as in Example 1, except that the angles of the convex patterns of the cylindrical mold 905 for groove formation with respect to the circumferential direction were set to 0.01°, 0.9°, and 3.0°, respectively, during the process of continuously forming the convex patterns of the cylindrical mold for groove formation. The electrophotographic belt manufactured in this manner was then subjected to evaluation.

[0064] (Example 7) After pressing the cylindrical mold 905 for grooving against the cylindrical belt holding mold 900 for half a turn, the cylindrical mold 905 for grooving was released and slid vertically by 10 μm, and then the cylindrical belt holding mold 900 was rotated in the opposite direction by a circumference of 8 mm. In this state, the cylindrical mold 905 for grooving was pressed against the cylindrical belt holding mold 900 for half a turn again, and then the cylindrical mold 905 for grooving was released. An electrophotographic belt was manufactured in the same manner as in Example 1, except for the operations described above. As a result, two second regions were provided in the circumferential direction of the electrophotographic belt. The electrophotographic belt manufactured in this manner was subjected to evaluation.

[0065] (Example 8) Two regions with different patterns were provided on the surface of a cylindrical mold 905, which has a diameter of 232.4 mm (circumference of 730 mm) and a length of 250 mm. In the first region of the cylindrical mold 905, which occupies a circumferential area of ​​704 mm, a convex shape is formed such that the angle with respect to the circumferential direction is 0.1°, and H=3.5 μm, Wb=2.0 μm, Wt=0.2 μm, and P=20 μm. In the second region, separate from the first region, a convex shape is formed such that the angle with respect to the circumferential direction is 0.1°, and H=3.5μm, Wb=2.0μm, Wt=0.3μm, and P=15μm. In this embodiment, an electrophotographic belt was processed using the cylindrical mold 905 described above.

[0066] In this embodiment, the second region of the cylindrical mold 905 is brought into contact with the cylindrical belt holding mold 900, and pressure is applied at a rate of 1.0 kN / s up to 8.0 kN. The phase of the cylindrical mold 905 is adjusted so that, at the same time as the force reaches 8.0 kN, the first region of the cylindrical mold 905 comes into contact with the cylindrical belt holding mold 900. Then, while maintaining the pressurizing force at 8.0 kN, the cylindrical belt holding mold 900 and the grooved cylindrical mold 905 are rotated. At the moment when the portion of the cylindrical belt holder 900 that begins to contact the cylindrical mold 905 for groove formation has passed one full rotation of the cylindrical belt holder 900, the second region of the cylindrical mold 905 comes into contact with the cylindrical belt holder 900. Subsequently, the load on the cylindrical mold 905 was reduced at a rate of 1.0 kN / s to release the cylindrical mold 905 for groove formation. The electrophotographic belts fabricated in this manner were then subjected to evaluation.

[0067] (Comparative Examples 2-8) An electrophotographic belt was manufactured in the same manner as in Examples 2 to 8, except that when forming grooves using an imprint processing apparatus, the cylindrical mold 905 and the cylindrical belt holding mold 900 were kept stationary, and the cylindrical mold 905 was pressurized and depressurized, similar to Comparative Example 1. The manufactured electrophotographic belt was then subjected to evaluation. Table 2 shows the evaluation results for the electrophotographic belts of Examples 1 to 8. Table 3 shows the evaluation results for the electrophotographic belts of Comparative Examples 1 to 8.

[0068] [Table 2]

[0069] [Table 3]

[0070] As shown in Table 2, in Examples 1 to 8, the groove 200 in the second region is composed of a groove 200-2 whose width gradually decreases toward the first circumferential direction A1 and a groove 200-3 whose width gradually decreases toward the second circumferential direction A2, as shown in Figure 1(b). Therefore, the change in specular reflected light output between the first and second regions was small. As a result, the deflection rate calculated using the above formula (1) was small, and the sensing characteristics were excellent. On the other hand, as shown in Table 3, in Comparative Examples 1 to 8, since the width of the grooves constituting the second region is constant, the specular reflected light output changes significantly between the first and second regions, and the deflection rate calculated using equation (1) becomes large. As a result, the sensing characteristics were inferior. [Explanation of Symbols]

[0071] 1 Photosensitive drum 2 Conductive rollers 3. Laser Scanner 4. Developer 5. Electrophotographic belt 6 Tension Roller 7 Drive rollers 8 Primary transfer roller 9. Secondary transfer roller 10 Current sensing circuit 11 Cleaning Blades 12 Feeding rollers 13 Conveyor rollers 14 Toner collection blade 15. Fuser 20 Paper feed cassettes 21 Paper output tray 41 Developing Roller 42 Developing container 43 Developing Blade 60 base layer 92 Secondary transfer opposing roller 104 Preform 107 Heating device 108 Blow type 109 Stretching rod 110 Blow air injection point 112 Blow Bottle 151 Heating roller 152 Pressure roller 160 Concentration detection sensor 161 Light-emitting element 162 Specular reflection photodetector 163 Irregular reflection light-receiving element 200 grooves 201 First Groove 202 Second Groove 300 1st area 301 Second area 302 Belt circumferential direction 900 Cylindrical Belt Holding Type 901 Base 905 Cylindrical mold S recording medium T Toner Image

Claims

1. An electrophotographic belt having an endless shape, a plurality of grooves extending in a circumferential direction of the electrophotographic belt are provided on an outer surface of the electrophotographic belt; The outer surface comprises at least a first region having n grooves in a direction perpendicular to a circumferential direction of the electrophotographic belt; a second region in which the number of the grooves in a direction perpendicular to the circumferential direction of the electrophotographic belt is greater than n, The grooves present in the second region are a first groove whose width gradually decreases in a first circumferential direction of the electrophotographic belt; and a second groove adjacent to the first groove, the width of which gradually decreases in a second circumferential direction opposite to the first circumferential direction (n is an integer of 1 or more).

2. 2. The electrophotographic belt according to claim 1, wherein the number of grooves per 1 mm width in the direction perpendicular to the circumferential direction of the electrophotographic belt in the first region is 8 to 500.

3. 3. The electrophotographic belt according to claim 1, wherein the number of said grooves in said second region is 2n-10 or more and 2n+10 or less.

4. As the width of the first groove decreases, the depth of the first groove decreases, 4. The electrophotographic belt according to claim 1, wherein the depth of said second groove gradually decreases as the width of said second groove gradually decreases.

5. 5. The electrophotographic belt according to claim 1, wherein when an angle θ is an angle that the groove in the first region makes with a straight line parallel to the circumferential direction, θ≠0°.

6. The electrophotographic belt according to claim 5, wherein the angle θ is greater than −3° and less than +3°.

7. 7. The electrophotographic belt according to claim 1, wherein the width of the grooves in the first region and the second region is within a range of 0.10 μm to 3.00 μm.

8. 8. The electrophotographic belt according to claim 1, wherein the width of said groove in said first region is constant.

9. The electrophotographic belt according to any one of claims 1 to 8, wherein the electrophotographic belt has a base layer having an endless shape and a surface layer on an outer circumferential surface of the base layer, and the groove is provided on an outer periphery of the surface layer.

10. An electrophotographic image forming apparatus comprising an endless intermediate transfer belt and a cleaning member in contact with an outer peripheral surface of the intermediate transfer belt, 10. An electrophotographic image forming apparatus, wherein the intermediate transfer belt is the electrophotographic belt according to claim 1.

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