Intermediate transfer belt and image forming apparatus

Abstract

To provide a configuration that can achieve high durability and can detect a developer image formed on an intermediate transfer belt with high accuracy by using an optical sensor.SOLUTION: An intermediate transfer belt has a first layer, and a second layer that is provided in contact with a first surface of the first layer located outside the intermediate transfer belt during use and can transmit light. The first surface of the first layer has first grooves extending in a first direction along a circumferential direction of the intermediate transfer belt. A second surface of the second layer located on the opposite side of the side where the first layer is present has second grooves extending in a second direction along the circumferential direction. The first grooves are provided in the first surface in the number equal to or more than 80 / mm in a width direction orthogonal to the circumferential direction.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an intermediate transfer belt and an image forming apparatus in which the intermediate transfer belt is used, and more particularly to an electrophotographic image forming apparatus and an intermediate transfer belt used in the electrophotographic image forming apparatus. [Background technology]

[0002] Conventionally, electrophotographic image forming apparatuses have included an intermediate transfer type image forming apparatus that uses an intermediate transfer member. In an intermediate transfer type image forming apparatus, a toner image formed on a photosensitive drum as an image carrier is primarily transferred to the intermediate transfer member, and then the toner image on the intermediate transfer member is secondarily transferred onto a recording material. An intermediate transfer belt formed of an endless belt is widely used as the intermediate transfer member.

[0003] In an intermediate transfer type image forming apparatus, toner (secondary transfer residual toner) remains on the intermediate transfer belt after the secondary transfer process, so a cleaning process is required to remove the secondary transfer residual toner from the intermediate transfer belt before transferring the next image to the intermediate transfer belt.

[0004] Meanwhile, a blade cleaning method is widely adopted for the cleaning process. In the blade cleaning method, a cleaning blade disposed downstream of the secondary transfer unit physically scrapes and collects residual toner from the moving intermediate transfer belt in the direction of movement of the surface of the intermediate transfer belt (hereinafter referred to as the "belt transport direction").

[0005] The cleaning blade is generally made of an elastic material such as urethane rubber. The cleaning blade is disposed so that its free end extends upstream in the direction of rotation of the intermediate transfer belt (the direction of movement of the surface), and the edge of the free end may be pressed against the intermediate transfer belt.

[0006] Furthermore, in order to improve durability, a configuration has been proposed in which the surface of the intermediate transfer belt is given a predetermined shape to reduce the frictional force between the intermediate transfer belt and the cleaning blade (Patent Document 1).

[0007] Specifically, in Patent Document 1, grooves are formed on the surface of the intermediate transfer belt at intervals of 2 to 10 μm, thereby reducing the coefficient of friction between the cleaning blade and the surface of the intermediate transfer belt.

[0008] In addition, a configuration has been proposed in which the position of a toner image drawn (primary transfer) on an intermediate transfer belt is detected (hereinafter referred to as "calibration") in order to align the toner images formed on multiple photosensitive elements arranged along the belt transport direction (Patent Document 2).

[0009] Specifically, in Patent Document 2, a pattern image for position detection (hereinafter referred to as a "calibration patch") is formed for each color on an intermediate transfer belt moving at a predetermined speed, and the position is detected by a detection means provided downstream of the image forming unit in the belt movement direction. Furthermore, positional deviation for each color is corrected based on the results detected by the detection means.

[0010] Optical sensors are generally used as the detection means for "calibration." In "calibration," the presence or absence of toner is detected by the "difference in the amount of reflected light" (output of the optical sensor) between the area covered with the toner image and the other areas on the intermediate transfer belt, and the "position" of the toner image is detected (determined).

[0011] The optical sensor can also detect the intensity of the "specularly reflected light" reflected at an equal reflection angle by irradiating light onto the intermediate transfer belt at a predetermined angle of incidence (for example, 20°) and the intensity of the "diffusely reflected light," which is diffused light.

[0012] In order to stably detect the "position" of the toner image, it is necessary to ensure sufficient contrast in the amount of reflected light between the toner and the intermediate transfer belt, and appropriate "reflectance" and "reflectance distribution characteristics" are required for the intermediate transfer belt. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Patent Publication No. 2019-191511 [Patent Document 2] Patent Publication No. 2010-97120 Summary of the Invention [Problem to be solved by the invention]

[0014] However, in the configuration of Patent Document 1, when forming (processing) a groove shape on the surface of the intermediate transfer belt, there may be areas where the "groove depth" of the groove formed by processing is shallower (hereinafter referred to as "groove processing defects") due to the presence of "scratches" on the mold that holds the belt or "depressions" on the belt surface.

[0015] In particular, when the incident light of an optical sensor such as that in Patent Document 2 is irradiated onto a "groove processing defect area," the effect of "diffuse reflection" in the "groove processing defect area" is less than in areas with normal groove depth, and the "amount of specular reflection light" may be higher.

[0016] As a result, when a patch image for calibration is formed on the "groove processing defect area," the "reflected light amount" that should be reduced by the toner (image) may not be maintained at a sufficiently low level due to the influence of the "specularly reflected light" from the underlying belt surface. This may result in the optical sensor being unable to correctly detect the position of the toner image, resulting in a decrease in position detection accuracy.

[0017] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an intermediate transfer belt and an image forming apparatus that can achieve high durability and can detect developer images formed on the intermediate transfer belt with high accuracy using an optical sensor. [Means for solving the problem]

[0018] The intermediate transfer belt of the present invention is An endless intermediate transfer belt, The first layer and a second layer that is in contact with a first surface of the first layer that is positioned outside the intermediate transfer belt when in use, and that is capable of transmitting light; and the first surface of the first layer has a first groove extending in a first direction along the circumferential direction of the intermediate transfer belt; a second surface of the second layer located on the opposite side to the side on which the first layer is present has a second groove extending in a second direction along the circumferential direction; The first grooves are provided on the first surface at a density of 80 grooves / mm or more in a width direction perpendicular to the circumferential direction.

[0019] The image forming apparatus of the present invention further comprises: The intermediate transfer belt; an image forming means for forming an image on the intermediate transfer belt; an optical sensor that detects an image formed on the intermediate transfer belt by the image forming means; The present invention is characterized by having the following: [Effects of the Invention]

[0020] According to the configuration of the present invention, high durability can be achieved, and the developer image formed on the intermediate transfer belt can be detected with high accuracy using an optical sensor. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view of an image forming apparatus according to an embodiment of the present invention; [Figure 2] 1 is a conceptual cross-sectional view of an optical sensor used in an image forming apparatus according to an embodiment of the present invention; [Figure 3] A conceptual diagram showing the reflection characteristics of an optical sensor according to an embodiment of the present invention. [Figure 4] FIG. 1 is a conceptual diagram illustrating the positional relationship between an optical sensor and a position detection pattern according to an embodiment of the present invention. [Figure 5]FIG. 1 is a conceptual diagram illustrating a method for calculating a positional deviation amount in an embodiment of the present invention. [Figure 6] FIG. 1 is a conceptual diagram showing the correspondence between a position detection pattern and an output waveform from an optical sensor according to an embodiment of the present invention. [Figure 7] 1A and 1B are enlarged cross-sectional schematic diagrams of an intermediate transfer belt according to an embodiment of the present invention. [Figure 8] (a) A cross-sectional conceptual diagram of an imprint processing apparatus according to an embodiment of the present invention; (b) A cross-sectional conceptual diagram of a mold used in imprint processing. [Figure 9] 1 is a cross-sectional view of a wrapping film processing device according to an embodiment of the present invention; [Figure 10] (a) is a conceptual diagram showing the positional relationship between a groove processing defect portion and a position detection pattern in each example and comparative example according to the embodiment of the present invention; (b) is a conceptual diagram showing the correspondence relationship between the position detection pattern and an output waveform from an optical sensor. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the image forming apparatus 100 of the present invention and the intermediate transfer belt 8 used in the image forming apparatus 100 will be described. Note that unless otherwise specified, the present invention is not limited to the following embodiment.

[0023] (Configuration of image forming device) FIG. 1 is a conceptual cross-sectional view of an image forming apparatus according to an embodiment of the present invention.

[0024] 1 shows a vertical cross section of the image forming apparatus 100 of this embodiment as seen from the front. In the following description, the letters YMCK added to the end of the reference numerals indicate the toner colors, and matters common to all four colors will be omitted.

[0025] The image forming apparatus used was a laser beam printer of an electrophotographic process type capable of forming images at a process speed of 210 mm / s and 600 dpi, and compatible with legal size paper.

[0026] The image forming apparatus shown in Figure 1 is equipped with detachable process cartridges P. These four process cartridges P have the same structure. The difference is that they form images using toner of the color contained in the process cartridge, namely, yellow (Y), magenta (M), cyan (C), and black (K).

[0027] The process cartridge P has a toner container 23. It also has a photosensitive drum 1, which is an image carrier, a charging roller 2, a developing roller 3, a drum cleaning blade 4, and a waste toner container 24.

[0028] A laser unit 7 is disposed below the process cartridge P and exposes the photosensitive drum 1 based on an image signal. The photosensitive drum 1 is charged to a predetermined negative potential by applying a predetermined negative voltage to the charging roller 2, and then an electrostatic latent image is formed on the photosensitive drum 1 by the laser unit 7. This electrostatic latent image is reverse-developed by applying a predetermined negative voltage to the developing roller 3, and a toner image is formed on the photosensitive drum 1.

[0029] The toner used in this embodiment is composed of toner particles with an average particle size of 5.4 μm and silica fine particles with an average particle size of 20 nm externally added, and is negatively charged. The average particle size is the average particle size determined from the particle volume, which can be measured, for example, by the Coulter method.

[0030] The intermediate transfer belt unit is composed of an intermediate transfer belt 8, a drive roller 9, a tension roller 10 as a tension roller, and an opposing roller .

[0031] The intermediate transfer belt 8 is an endless belt made of a resin material with a conductive agent added thereto, having a length of 250 mm in the depth direction (hereinafter referred to as the longitudinal direction) in FIG. 1 and a circumference of 712 mm. The intermediate transfer belt 8 is stretched around three axes: a drive roller 9 with a diameter of 24 mm and a longitudinal surface length of 240 mm, a tension roller 10 with a diameter of 24 mm and a longitudinal surface length of 250 mm, and an opposing roller 28 with a diameter of 16 mm and a longitudinal surface length of 240 mm. The tension roller 10 also stretches the intermediate transfer belt 8 with a total tension of 100 N. The configuration of the intermediate transfer belt 8 will be described in detail below.

[0032] A primary transfer roller 6 as a primary transfer member is disposed inside the intermediate transfer belt 8, facing the photosensitive drum 1, and a transfer voltage is applied to the primary transfer roller 6 by a voltage application means (not shown).

[0033] The optical sensors 27 are disposed at positions 100 mm apart on both sides of the center position in the width direction Z3 of the intermediate transfer belt. The optical sensors 27 are configured to detect a calibration patch, which is a test image, formed on the intermediate transfer belt 8, with the drive roller 9 as the opposing member. The configuration of the optical sensors will be described in detail later.

[0034] First, the toner image formed on the photosensitive drum 1 is rotated in the direction of the arrow by each photosensitive drum 1. Then, the intermediate transfer belt 8 is rotated in the direction of the arrow Z by an intermediate transfer belt driving means (not shown), and a positive voltage is applied to the primary transfer roller 6, thereby performing primary transfer onto the intermediate transfer belt 8. The toner images on the photosensitive drum 1Y are sequentially primary transferred onto the intermediate transfer belt 8, and the four color toner images are transported in a superimposed state to a secondary transfer portion (secondary transfer nip) formed by the secondary transfer roller 11 and the opposing roller 28, which are secondary transfer members.

[0035] The feeding and conveying device 12 has a paper feed roller 14 that feeds the recording material K from a paper feed cassette 13 that stores the recording material K, and a pair of conveying rollers 15 that convey the fed recording material K. The recording material K conveyed from the feeding and conveying device 12 is then conveyed to a secondary transfer unit by a pair of registration rollers 16.

[0036] A positive voltage is applied to the secondary transfer roller 11 in order to transfer the toner image from the intermediate transfer belt 8 to the recording material K. This allows the toner image on the intermediate transfer belt 8 to be secondarily transferred to the recording material K being conveyed. The recording material K with the transferred toner image is conveyed to a fixing device 17, where it is heated and pressed by a fixing film 18 and a pressure roller 19 to fix the toner image to the surface. The fixed recording material K is then discharged by a pair of discharge rollers 20.

[0037] After the toner image is transferred onto the recording material K, the primary transfer residual toner remaining on the surface of the photosensitive drum 1 is removed by the drum cleaning blade 4.

[0038] Furthermore, when the intermediate transfer belt 8 rotates (moves) in the direction of the arrow Z, the secondary transfer residual toner is scraped off by a cleaning blade 21 serving as a cleaning member and collected in a waste toner collection container 22.

[0039] The cleaning blade 21 is made of a zinc-plated steel plate with a longitudinal length of 240 mm and a thickness of 3 mm, to which a urethane rubber blade with a longitudinal length of 230 mm, a thickness of 2 mm, and an angle of 77 degrees according to JIS K 6253 has been attached. The free end of the cleaning blade 21 abuts against the outer circumferential surface of the intermediate transfer belt 8 so as to extend upstream in the movement direction (Z direction) of the intermediate transfer belt 8. The cleaning blade 21 is pressed against the tension roller 10 via the intermediate transfer belt 8 with a linear pressure of 0.49 N / cm, for a total pressure of approximately 11.3 N.

[0040] The control board 25 is a board on which electric circuits for controlling the image forming apparatus are mounted, and a CPU 26 serving as a control unit is mounted on the control board 25. The CPU 26 controls an intermediate transfer belt drive motor which is a drive source for the intermediate transfer belt 8 involved in conveying the recording material K, as well as drive sources (not shown) for the feed / convey device 12, the pair of registration rollers 16, and the fixing device 17. The CPU 26 also collectively controls the operations of the image forming apparatus, such as control of a drum motor (not shown) which is a drive source for the process cartridge P, control of various image signals related to image formation, density correction control based on the detection results of the optical sensor 27, and control related to failure detection.

[0041] (Optical sensor configuration) The optical sensor 27 used in the image forming apparatus of this embodiment will be described with reference to FIG.

[0042] FIG. 2 is a conceptual cross-sectional view of an optical sensor used in an image forming apparatus according to an embodiment of the present invention.

[0043] Specifically, FIG. 2 shows a cross section of the optical sensor 27 and the intermediate transfer belt in the width direction (Z3) of the intermediate transfer belt.

[0044] As shown in FIG. 2, the optical sensor 27 includes a light emitting element 272 such as an LED, a regular reflection light receiving element 273 such as a photodiode, and a holder 274.

[0045] The light emitting element 272 uses near-infrared LED light with a central wavelength λ=840 nm, and can irradiate the surface of the intermediate transfer belt 8 from an incident angle θi=-20° when the normal direction of the intermediate transfer belt 8 is 0°. At this time, the regular reflection light receiving element 273 can receive the reflected light at a reflection angle θm=20°.

[0046] The position of the calibration patch T is detected by irradiating the surface of the intermediate transfer belt 8 or the calibration patch T with light from the light emitting element 272 and measuring the light reflected therefrom with the specular reflection light receiving element 273.

[0047] Next, the output characteristics of the optical sensor 27 will be described with reference to FIG.

[0048] FIG. 3 is a conceptual diagram showing the reflection characteristics of an optical sensor according to an embodiment of the present invention.

[0049] Specifically, FIG. 3 shows the relationship between the amount of toner on the intermediate transfer belt 8 and the output of the optical sensor 27.

[0050] When the amount of toner on the intermediate transfer belt increases, the toner diffuses the irradiated light and simultaneously covers the surface (outer surface) of the intermediate transfer belt, which is the base, reducing the specularly reflected light from the surface of the intermediate transfer belt. The position of the calibration patch T on the intermediate transfer belt can be detected from the difference in the output of this reflected light.

[0051] (Calibration control) Next, the calibration control will be described with reference to FIG.

[0052] FIG. 4 is a conceptual diagram showing the positional relationship between the optical sensor and the position detection pattern in the embodiment of the present invention.

[0053] Specifically, FIG. 4 shows the positional relationship between the optical sensor 27 and the calibration patch T.

[0054] As mentioned above, the optical sensors 27 are positioned 100 mm away from the center position of the intermediate transfer belt in the width direction Z3 on both sides to detect the calibration patches T formed on the left and right sides (width direction) of the intermediate transfer belt 8.

[0055] The first region 275 represents a region detectable by the optical sensor 27. In this embodiment, the optical sensor 27 (light-emitting element 272) is configured to receive (detect) emitted and reflected light within an irradiation width range (width direction Z3) of 2 mm over the entire circumference of the belt (circumferential direction Z) as the belt rotates.

[0056] In this embodiment, the calibration patch T is composed of a position detection pattern F in the rotational (circumferential) direction Z of the intermediate transfer belt (hereinafter referred to as the "sub-scanning direction") and a position detection pattern S in the width direction Z3 of the intermediate transfer belt (hereinafter referred to as the "main scanning direction"). Images of both patterns are formed in the order of yellow, magenta, cyan, and black.

[0057] Next, a method for detecting the pattern position using a calibration patch will be described in detail with reference to FIG.

[0058] FIG. 5 is a conceptual diagram showing a method for calculating the amount of positional misalignment in an embodiment of the present invention.

[0059] Specifically, FIG. 5 shows the actual drawing position and the amount of deviation from the ideal position of the calibration patch.

[0060] Here, the "amount of deviation" refers to the amount of deviation between the actually detected position and the ideal position or detection timing.

[0061] The ideal position or detection timing is determined based on a specific reference, which may be a reference position marking provided on the intermediate transfer belt or the position or timing at which a reference color is detected.

[0062] Next, detection of pattern positional deviation in the sub-scanning direction (Z) will be described using "pattern F" shown in FIG.

[0063] "Pattern F" shown in Fig. 5 is a pattern for detecting the position in the sub-scanning direction that has actually been formed. On the other hand, "Pattern F'" shown in Fig. 5 is a pattern in an ideal position (i.e., when the deviation is 0).

[0064] Here, if the timing when pattern F is detected by the sensor is "t" and the timing when ideal pattern F' should be detected is "t'", the "deviation df" in the sub-scanning direction (Z) can be calculated using the following formula. df = (t-t') x ps (ps is the surface movement speed of the intermediate transfer belt)

[0065] Next, detection of positional deviation in the main scanning direction (Z3) will be described.

[0066] "Pattern S" shown in Fig. 5 is a pattern for detecting the position in the main scanning direction that has actually been formed. On the other hand, "Pattern S'" shown in Fig. 5 is a pattern in an ideal position (i.e., when the deviation is 0).

[0067] In this embodiment, "pattern S" is a dogleg pattern consisting of two lines that intersect at a 90-degree angle, and the angle of the line portion is 45 degrees with respect to the sub-scanning direction (Z). In this pattern, the line portion passes the optical sensor twice, so the timing of the first pass is t1 and the timing of the second pass is t2.

[0068] Similarly, if the timings at which the ideal pattern S' should be detected are "t1'" and "t2'", then the "registration deviation ds" in the main scanning direction (Z3) can be calculated by the following formula. ds=1 / 2×{(t2'-t1')-(t2-t1)}×ps (ps is the surface movement speed of the intermediate transfer belt)

[0069] A method for detecting the timing at which the calibration patch T passes over the optical sensor 27 will be described in detail with reference to FIG.

[0070] FIG. 6 is a conceptual diagram showing the correspondence between the position detection pattern and the output waveform from the optical sensor in the embodiment of the present invention.

[0071] Specifically, FIG. 6 shows the output (waveform W) when a pattern F for detecting the position in the sub-scanning direction (Z) passes through the optical sensor 27.

[0072] When the optical sensor 27 is detecting something other than the position detection pattern F (the intermediate transfer belt substrate), a large amount of reflected light is incident on the specular reflection light-receiving element 273, resulting in a large sensor output. When the position detection pattern F passes through the optical sensor 27 (the first area, which is the detection range of the optical sensor), the amount of reflected light incident on the specular reflection light-receiving element 273 is reduced due to the presence (blocking) of toner, resulting in a small sensor output.

[0073] On the other hand, the sensor output waveform W is output as a "digital signal V" through a "comparison circuit" (not shown) of the control board 25.

[0074] 6, dotted line X represents the threshold value used by the comparator circuit to determine ON / OFF, and the digital signal V output from the comparator circuit turns ON when it falls below the threshold value (dotted line X). CPU 26 also refers to digital signal V, measures the time from when the signal switches to "ON" to when it returns to "OFF," and detects half the time during which the signal is "ON" as the time "t" when the sensor detects position detection pattern F.

[0075] Then, the CPU 26 calculates the "deviation df" in the sub-scanning direction (Z) based on the difference between the detected timing "t" and the timing "t'" at which the ideal pattern F' should be detected.

[0076] In this embodiment, after the amount of misalignment is detected, the misalignment is corrected by correcting the image forming conditions in accordance with the detected amount of misalignment.

[0077] Specifically, the image formation position for each color can be made closer to the ideal position by adjusting the timing for sending each image signal for Y, M, C, and K. Also, although the detection and correction of the amount of misalignment in the sub-scanning direction has been described in this embodiment, misalignment in the main scanning direction and misalignment in the tilt of the main scanning direction can also be corrected in the same way based on the misalignment in the pattern detection timing.

[0078] (Intermediate transfer belt configuration) Next, the configuration of the intermediate transfer belt 8 of this embodiment will be described with reference to FIGS. 7(a) and 7(b).

[0079] 7(a) and (b) are enlarged conceptual diagrams of a cross section of an intermediate transfer belt according to an embodiment of the present invention.

[0080] Specifically, Figures 7(a) and (b) show a schematic enlargement of an area of ​​approximately 30 μm of the intermediate transfer belt 8 in a direction (width direction Z3) approximately perpendicular to the belt circumferential direction (Z).

[0081] As shown in FIGS. 7(a) and 7(b), in this embodiment, the intermediate transfer belt 8 is an endless belt member made up of two layers: a base layer 81 as a first layer and a surface layer 82 as a second layer.

[0082] A first surface 811, which is the surface on one side in the thickness direction of the base layer 81, has a plurality of fine vertical grooves 81m formed thereon so as to extend in a first direction (Z1) along the circumferential direction Z.

[0083] In addition, a second surface 821, which is the surface of the surface layer 82 opposite the base layer 81 in the thickness direction, has a plurality of fine vertical grooves 82m formed to extend in a second direction (Z2) along the circumferential direction Z.

[0084] In this embodiment, the first direction Z1 and the second direction Z2 are both the same direction as the circumferential direction Z, but they do not have to be the same direction as long as they are along the circumferential direction Z. For example, the first direction Z1 and the second direction Z2 may have an intersecting angle of 15° or less with respect to the circumferential direction Z.

[0085] In this embodiment, the intermediate transfer belt may further include a third layer on the opposite side of the first layer from the second layer.

[0086] In this embodiment, a wrapping film is used as a method for forming the fine groove shape on the surface of the base layer 81. Also, in this embodiment, an imprint process is used as a method for forming the fine groove shape on the surface of the surface layer 82. The shape of the fine groove will be described later.

[0087] The layer structure of the intermediate transfer belt of this embodiment will be described in detail below.

[0088] The base layer 81, which serves as the first layer, is obtained by adding an ionic conductive agent to polyethylene naphthalate resin (PEN) and polyether ester amide (PEEA) and then extruding the resulting material. The first layer is a seamless, belt-shaped layer with a thickness of 60 μm and a volume resistivity of 1×10^10 Ω·cm. Although PEN and PEEA resins are used as the material for the base layer 81, other thermoplastic resins may also be used. For example, materials such as polyester, polycarbonate, polyarylate, polyether ether ketone, acrylonitrile-butadiene-styrene copolymer (ABS), polyphenylene sulfide (PPS), and polyvinylidene fluoride (PVdF) may also be used. Mixed resins of these materials may also be used.

[0089] The ion conductive material used as the conductive agent for the base layer 81 was an alkali metal salt.

[0090] The thickness of the base layer 81 is preferably 30 μm or more in order to prevent deformation and wrinkles due to the imprinting process.

[0091] The second surface layer 82 is a transparent acrylic resin layer having a thickness of 2 μm, obtained by dip-coating the base layer 81 with a curable composition obtained by dissolving and dispersing a polyfunctional acrylic monomer, a photopolymerization initiator, and conductive metal oxide particles in a solvent, followed by ultraviolet irradiation. Other methods may be used to apply the surface layer 82, such as spray coating, flow coating, shower coating, roll coating, and spin coating, as long as they can form a uniform film. Furthermore, if the thickness of the surface layer 82 is to be greater than 3 μm, it is preferable that the thickness be 3 μm or less in order to prevent cracks in the surface layer due to the curvature of the belt when it is stretched.

[0092] The formation of fine grooves on the belt surface by imprinting will be described in detail with reference to FIGS. 7(a) and 7(b).

[0093] Generally, when urethane rubber and acrylic resin are rubbed against each other, frictional resistance is high, which can easily cause the cleaning blade to squeal or turn up. Therefore, in this embodiment, longitudinal grooves as second grooves are formed on the surface of surface layer 82 along the circumferential direction of the belt at a predetermined groove spacing (number of grooves). Note that in this embodiment, the groove spacing is measured as the distance between the starting points of adjacent protrusions, as indicated by p in FIG. 7, and the number of grooves is calculated as the number per mm based on the average groove spacing p.

[0094] Next, the imprint process will be described in detail with reference to FIGS.

[0095] Fig. 8(a) is a cross-sectional view of an imprint processing apparatus according to an embodiment of the present invention, and Fig. 8(b) is a cross-sectional view of a mold used in the imprint processing.

[0096] Specifically, Fig. 8(a) shows the imprint processing device as viewed from the cylindrical axial direction of the intermediate transfer belt 8. Also, Fig. 8(b) shows a cross section along the cylindrical axis of a mold used in the imprint processing.

[0097] In the imprinting process, first, the intermediate transfer belt 8 having the surface layer 82 formed on the base layer 81 is pressed into a core 91 (diameter 227 mm, made of carbon tool steel).

[0098] A cylindrical mold 92 with a diameter of 50 mm and a length of 250 mm was pressed against the surface of the inserted intermediate transfer belt with a predetermined pressing force of about 1000 to 2500 N. As shown in Fig. 8(b), the surface of the mold 92 was provided by cutting with wedge-shaped protrusions, each with a base length of about 2 µm and a height of about 2 µm, parallel to the circumferential direction of the cylinder and at predetermined intervals.

[0099] By changing the spacing between the protrusions, it is possible to change the groove spacing on the belt (the number of grooves on the surface layer). When the mold of this embodiment is used, it is possible to obtain a maximum groove spacing of 250 mm (minimum number of grooves: 0.004 grooves / mm) and a minimum groove spacing of 2 μm (maximum number of grooves: 500 grooves / mm) on the surface layer.

[0100] The minimum groove spacing can be further reduced by making the length of the bottom of the convexities 2 μm or less, but this would result in insufficient strength of the convexities and the risk of deformation during imprinting. Therefore, it is preferable to limit the minimum groove spacing to 2 μm and the maximum number of grooves per unit length to 500 / mm.

[0101] The mold 92 was heated to a temperature of approximately 130° C. by a heater (not shown). Furthermore, while in contact with the mold 92, the core 91 was rotated once at a peripheral speed of 264 mm / s to follow the mold 92, and then the mold 92 was separated, thereby obtaining an intermediate transfer belt 8 having a fine groove pattern processed on the surface of the surface layer 82.

[0102] (Impact on intermediate transfer belt structure due to adhesion of foreign matter during processing) In the process of creating a groove shape by imprinting, if the imprinting is performed while foreign matter such as dust and fluff in the air is present between the intermediate transfer belt 8 and the core 91, a depression may occur on the surface of the core 91.

[0103] Furthermore, the surface of the core 91 may be damaged due to carelessness when the intermediate transfer belt 8 is pressed into or removed from the core 91.

[0104] In the area where the "dent" has occurred in the core 91, the desired pressing force cannot be applied when the die 92 is pressed against it, and the groove shape may be machined shallower than in the normal area (i.e., a "groove processing defect" may occur).

[0105] In such "grooved defect areas," the diffused reflection effect of the microgrooves is reduced compared to areas with normal microgrooves, and the amount of specularly reflected light can be increased. As a result, when a calibration patch is formed on a grooved defect area, the amount of reflected light that should be reduced by the toner is not sufficiently reduced due to the strong specular reflection light from the underlying belt surface. This can cause the position of the toner image to be unable to be detected correctly, which can reduce the accuracy of position detection.

[0106] This embodiment is characterized in that a plurality of fine vertical grooves are also formed as first grooves on the surface of the base layer 81 in order to suppress an increase in the amount of reflected light at groove-processed defects.

[0107] Next, the details of the microgroove processing on the base layer surface will be described with reference to FIG.

[0108] FIG. 9 is a cross-sectional conceptual diagram of a wrapping film processing device according to an embodiment of the present invention.

[0109] Specifically, FIG. 9 shows the state in which the fine groove processing device using the wrapping film is viewed from the cylindrical axial direction of the intermediate transfer belt 8.

[0110] When processing the microgrooves in the base layer 81, the base layer 81 in a seamless belt shape obtained by extrusion processing is pressed into a core 93 (diameter 227 mm, made of carbon tool steel). With a wrapping film 94 pressed against the inserted base layer 81 by a backup roller 95 (diameter 50 mm, made of rubber) at 0.2 N / mm2, the core 91 is rotated a little more than one revolution at a peripheral speed of 264 mm / s while the wrapping film 94 is fed at 4 mm / s, and then the backup roller 94 is separated, thereby obtaining a base layer 81 with a microgroove pattern processed on its surface.

[0111] The surface layer 82 was formed on the obtained base layer 81, and imprint processing was performed to obtain the intermediate transfer belt 8 of this embodiment.

[0112] (Evaluation method) [Number of grooves (average pitch)] The micro-groove shapes obtained by imprint processing and wrapping film processing were measured using a laser microscope VK-X250 (Keyence Corporation).

[0113] The number of grooves in the base layer 81 was determined by observing the reflected image from the surface of the base layer using a belt before the surface layer 82 was formed.

[0114] The number of grooves in the surface layer 82 was obtained by observing a reflected image from the surface of the surface layer 82 after imprint processing.

[0115] The measurement area was the "first area 275" of the intermediate transfer belt, a range of approximately 2 mm in width at positions 100 mm away on both sides from the center position in the width direction Z3. Measurements were taken at a total of eight locations, two in the width direction (Z3) and four in the circumferential direction (Z).

[0116] The measurement was performed using a 150x objective lens over an area of ​​approximately 70 x 90 μm. The number of grooves within a 90 μm width was counted, and the quotient for the 90 μm width was calculated to obtain the average pitch between grooves and the number of grooves that could exist within a 1 mm width.

[0117] The number of grooves in the base layer 81 can be determined even after the surface layer 82 has been formed by cutting the belt in the thickness direction with a razor or the like and observing the cross section with an electron microscope.

[0118] Groove depth (average groove depth) The measurement of the average groove depth (hereinafter sometimes simply referred to as "groove depth") will be described below.

[0119] Specifically, after measuring the same area as in the groove number measurement, a measurement line was drawn perpendicular to the groove direction using the obtained two-dimensional height information in line profile measurement mode, and the groove depth for each groove was obtained by measuring the apex where the height between adjacent vertical grooves is greatest and the height to the groove bottom.

[0120] As shown in Fig. 7(a), grooves formed by imprint processing on the surface layer 82 may have raised groove ends, so when a raised shape was formed, the higher of both ends was taken as the apex to obtain the groove depth (d2). Also, as shown in Fig. 7(b), when a raised shape was not formed at the groove ends, the higher of the flat ends on both sides was taken as the apex, and the height to the groove bottom was measured to obtain the groove depth (d2) for each groove.

[0121] Regarding the groove depth obtained by wrapping film processing of the base layer 81, there was no tendency for both ends to bulge, so as with the grooves in the surface layer 82 in Figure 7(b), the higher of the flat ends on both sides was used as the apex, and the height to the bottom of the groove was measured to obtain the groove depth (d1) for each groove.

[0122] The groove depth was measured for all grooves within a visual field of approximately 70 × 90 μm, and the average depth of all grooves measured at eight locations was calculated to obtain the "average groove depths d1 and d2."

[0123] Regarding the groove depth (d1) of the base layer 81, even after the surface layer 82 is formed, the average groove depth d1 can be obtained by cutting the belt in the thickness direction with a razor or the like and observing the cross section with an electron microscope.

[0124] [20 degree gloss value] The reflection characteristics of the intermediate transfer belt 8 were evaluated using the 20-degree gloss value based on JIS Z 8741. The 20-degree gloss value was measured using a surface reflection analyzer RA532H (manufactured by Canon Inc.).

[0125] [Amount of false positives in position detection] Next, the influence of the groove processing defect portion 102 on the position detection of the calibration patch T was evaluated by the method shown in FIG.

[0126] 10(a) is a conceptual diagram showing the positional relationship between the groove processing defect and the position detection pattern in each example and comparative example according to the embodiment of the present invention, and FIG. 10(b) is a conceptual diagram showing the correspondence relationship between the position detection pattern and the output waveform from the optical sensor.

[0127] Specifically, Fig. 10(a) shows the positional relationship between the optical sensor 27, the calibration patch T, and the groove processing defect portion 102. Fig. 10(b) shows the output of the optical sensor 27 obtained when reading the belt and the calibration patch shown in Fig. 10(a).

[0128] In FIG. 10(a), the optical sensors 27 are arranged at positions 100 mm apart on both sides of the center position in the width direction of the intermediate transfer belt, but for simplicity, only one side is shown.

[0129] Three patterns, F-1, F-2, and F-3, which are position detection patterns in the sub-scanning direction, were formed as calibration patches T. F-1 to F-3 were yellow toner images, 10 mm in size in the main scanning direction and 2 mm in the sub-scanning direction, formed on the belt at intervals of 6 mm in the sub-scanning direction.

[0130] In this embodiment, the "groove processing defect portion 102" was evaluated in an experiment assuming a size of about 2 mm. Specifically, in order to form the groove processing defect portion 102, first, a "dent (defect shape)" with a size of about 2 mm was formed at a position on the core 91 corresponding to the reading portion of the optical sensor 27. Then, by performing imprint processing on the surface of the belt, a second region (groove processing defect portion 102) in which the average groove depth d2' is shallower than the average groove depth d2 of the normal portion was formed.

[0131] Thus, an intermediate transfer belt having a "groove processing defect portion 102", which is a second region with a shallower groove depth (d2' < d2) than other portions (d2), can be intentionally formed inside the first region 275.

[0132] Next, for the groove processing defect portion 102, image formation was performed so that the position detection pattern F-2 exactly covered half of the "groove processing defect portion".

[0133] As shown in FIG. 10(b), the waveform W is an output waveform obtained when the belt and the position detection patterns F-1 to F-3 are read by the optical sensor 27.

[0134] In the position detection pattern F-2, it was found that the time during which the output decreases tends to be short, and the output immediately after the position detection pattern tends to be extremely high.

[0135] This phenomenon is because in the groove processing defect portion, the specular reflection effect due to the fine grooves decreases and the amount of specularly reflected light increases, so the amount of light received by the specular reflection light receiving element 273 increases.

[0136] In the region overlapping with the groove processing defect portion of the position detection pattern, the amount of reflected light from the belt base is very high. Therefore, the relationship between the sensor output and the toner loading amount shown in FIG. 3 changes, and the sensor output becomes high even at the same loading amount.

[0137] As a result, in F-2, it is considered that the time during which the output W decreases in the position detection pattern portion becomes short.

[0138] On the other hand, as shown in FIG. 10(b), the signal V is a digital signal obtained by discriminating the ON / OFF state of the waveform W using a comparison circuit with a threshold value X.

[0139] As mentioned above, the timings t1 to t3 at which the position detection patterns F-1 to F-3 are detected by the sensor are half the time that the digital signal V is ON. Then, based on the difference from the ideal timings t1' to t3', the deviations df1 to df3 for each pattern were calculated.

[0140] To evaluate the effect of the groove processing defect 102 on the position detection of the calibration patch T, the amount of false detection in position detection due to the influence of the groove processing defect was calculated by taking the difference between df2 and (df1+df3) / 2, which is the average deviation between F-1 and F-3, which have no defect.

[0141] In this embodiment, when the amount of erroneous detection in position detection due to groove processing defects becomes 80 μm or more, the deviation between colors becomes an unacceptable level, so the acceptability was determined using 80 μm (or less) as the "threshold value."

[0142] <Example> The effects of the present embodiment will be described below using Examples 1 to 7 and Comparative Examples 1 to 4. Table 1 shows the groove processing conditions, number of grooves, and average groove depth d1 for the base layer. Table 1 also shows the number of grooves, average groove depth d2, and 20-degree gloss for the surface layer. Table 1 also shows the groove depth d2' for groove-processed defects in the surface layer, the "false detection amount" of position detection, the judgment results for deviation (tolerance), and the judgment results for frictional resistance of the surface layer (surface).

[0143] [Table 1]

[0144] (Examples 1 to 3) In Examples 1 to 3, the surface layer was subjected to the same imprint processing conditions, while the abrasive grain size of the lapping film used to process the base layer was changed to 2, 9, or 1 μm. In Examples 1 to 3, the "false detection amount" caused by groove processing defects was all less than 80 μm, which is acceptable.

[0145] In this embodiment, the influence of the "grooving defect portion" on the output waveform W of the optical sensor can be suppressed by reducing the specularly reflected light from the base layer surface 811 at the groove processing defect portion.

[0146] Specifically, since the surface layer 82 in the configuration of this embodiment is a transparent acrylic resin layer, incident light irradiated onto the surface of the intermediate transfer belt is reflected from the surface of the surface layer 811, and after passing through the surface layer, is reflected from the surface of the base layer 821, passes through the surface of the surface layer again, and is reflected in the direction of regular reflection. In Examples 1 to 3 of this embodiment, it is believed that as a result of forming fine grooves on the surface of the base layer 811 under appropriate conditions, the transmitted light was diffused by the fine grooves (first grooves 81m), and the regular reflected light was significantly reduced.

[0147] As a result, in the configurations of Examples 1 to 3, it was possible to effectively suppress a decrease in the accuracy of detecting the position of the calibration patch T due to the influence of the groove processing defects.

[0148] In addition, in Examples 1 to 3, since the conditions such as pressure and speed during lapping film processing were kept constant, it was found that the number of grooves decreased and the groove depth tended to increase as the abrasive grain size increased.

[0149] The results of Examples 1 to 3 confirmed that when the number of fine grooves (first grooves 81m) on the base layer surface 811 is in the range of 80 grooves / mm or more, the decrease in the position detection accuracy of the calibration patch T due to the influence of groove processing defects can be suppressed.

[0150] Although it is possible to increase the number of microgrooves on the base layer surface to more than 500 grooves / mm by using a lapping film with an abrasive grain size of less than 1 μm, the small abrasive grain size may result in a shallow groove depth of 0.1 μm or less. Therefore, in the lapping film processing method, in order to create a stable groove shape extending in the circumferential direction Z, it is desirable to limit the number of microgrooves 81 m on the base layer surface 811 to 500 grooves / mm. Furthermore, when the number of first grooves 81 m is 80 to 500 grooves / mm, the average groove depth of the first grooves 81 m can be set to a range of 0.2 to 0.5 μm.

[0151] (Comparative Examples 1 and 2) In Comparative Examples 1 and 2, the surface layer 82 was subjected to the same imprint processing conditions as in Examples 1 to 3, but lapping film processing was not performed on the base layer 81 in Comparative Example 1. In Comparative Example 2, the abrasive grain size of the lapping film was changed to 20 μm.

[0152] In Comparative Examples 1 and 2, the "amount of false detection" caused by groove processing defects was 80 μm or more, which is unacceptable.

[0153] In the configuration of Comparative Example 1, since no fine groove processing was performed on the base layer 81, it is believed that the incident light that passed through the surface layer 82 was strongly specularly reflected from the base layer surface 821 and emitted as specularly reflected light together with the light reflected from the surface layer 811.

[0154] As a result, in Comparative Example 1, the amount of light received by the specular reflection light receiving element 273 increases in the weight area that overlaps with the groove processing defect in the thickness direction, and the time during which the "output W" of the position detection pattern F-2 (see FIG. 10(b)) decreases is thought to be shorter (compared to F-1 and F-3). Therefore, the deviation of t2 from t2' increases, and it is thought that the position of the position detection pattern F-2 was erroneously detected.

[0155] Furthermore, in the configuration of Comparative Example 2, as in Examples 1 to 3, the conditions such as pressure and speed during lapping film processing were kept constant, and as a result of increasing the abrasive grain size to 20 μm, the number of grooves on the base layer surface 811 decreased and the groove depth tended to increase.

[0156] As a result, in Comparative Example 2, the number of base layer grooves 81m was reduced to 42 grooves / mm, compared to 80 to 500 grooves / mm in Examples 1 to 3. As a result of the reduction in the number of grooves 81m, it is thought that the diffused reflection effect of the grooves in Comparative Example 2 was reduced (regular reflection was not suppressed), and the effects of Examples 1 to 3 were not obtained.

[0157] The results of Comparative Examples 1 and 2 show that when the number of grooves 81m in the microgroove processing on the base layer surface 811 is less than 80 / mm, it is difficult to suppress a decrease in the position detection accuracy of the calibration patch T due to the influence of groove processing defects. In other words, in order to maintain the position detection accuracy, it is necessary to form grooves 81m at least 80 / mm or more on the base layer surface 811.

[0158] Examples 4 to 7 In Examples 4 and 5, the base layer 81 was processed under the same wrapping film processing conditions as in Example 1, but the convex spacing of the mold 92 for the imprint processing of the surface layer 82 was changed. In addition, in the configurations of Examples 4 and 5, the "false detection amount" caused by groove processing defects was 80 μm or less, which is acceptable.

[0159] Furthermore, in Examples 6 and 7, the wrapping film processing conditions for the base layer 81 were the same as in Example 1, but the pressure applied in the imprint processing of the surface layer 82 was adjusted. Even in the configurations of Examples 6 and 7 in which the depth of the groove 82m in the surface layer 82 was changed by the pressure applied in the imprint processing, the "false detection amount" caused by groove processing defects was less than 80 μm in both cases, which is acceptable.

[0160] In addition, when comparing the "amount of false detection" in Examples 1, 4, and 5, it was found that the fewer the number of grooves 82m in the surface layer 82 (for example, Example 5), the smaller the "amount of false detection" becomes. Also, the fewer the number of grooves 82m in the surface layer 82 (for example, Example 5), the higher the 20-degree gloss value of the surface layer tends to be.

[0161] This indicates that the fewer the number of grooves 82m in the surface layer 82, the less diffused reflection there is from the surface grooves and the stronger the specular reflection from the surface layer. As a result, it is thought that the difference in the amount of specular reflection light between the "grooved defect area" and the "normal area" is small, and therefore the "amount of false detection" in position detection is relatively small.

[0162] Similarly, when comparing the "amount of false detection" in Examples 1, 6, and 7, it was found that the shallower the groove depth d2 of the surface layer 82 (for example, Example 7), the smaller the amount of false detection. Also, the shallower the groove depth d2 of the surface layer 82 (for example, Example 7), the higher the 20-degree gloss value of the surface layer 82 tends to be.

[0163] This indicates that the shallower the depth of the grooves 82m in the surface layer 82, the less diffused reflection there is from the surface grooves and the stronger the specular reflection from the surface layer. As a result, it is thought that the difference in the amount of specular reflection light between the "grooved defect area" and the "normal area" is small, and therefore the "amount of false detection" in position detection is relatively small.

[0164] Furthermore, in the configuration of Example 4, in which the number of grooves 82m in the surface layer 82 is large, and the configuration of Example 6, in which the depth d2 of the grooves 82m in the surface layer 82 is large, there is a tendency for diffused reflection due to the surface layer grooves to be large, and for specular reflection from the surface layer to be weak. As a result, it is thought that the "amount of false detection" became significant due to the large "difference" in the amount of specular reflection light between the "grooved defect area" and the "normal area." However, in the configurations of Example 4 and Example 6, it was possible to effectively suppress the decrease in the position detection accuracy of the calibration patch T due to the influence of the "grooved defect area," compared to Comparative Example 1, in which no grooves were formed in the base layer 81.

[0165] The results of Examples 1, 4, and 5 confirmed that when the number of fine grooves (second grooves 82m) on the surface 821 is in the range of 160 to 500 grooves / mm, the decrease in the position detection accuracy of the calibration patch T due to the influence of "groove processing defects" can be more effectively suppressed.

[0166] Note that even if the number of microgrooves 82m on the outer surface 821 is increased to more than 500 / mm, the effect of suppressing the deterioration of detection accuracy can be obtained, but as mentioned above, the strength of the protrusions on the mold may be insufficient, and deformation may occur during the imprinting process. For this reason, in this embodiment, it is preferable to limit the number of grooves 82m per unit length to 500 / mm.

[0167] Furthermore, the results of Examples 1, 6, and 7 confirmed that when the depth of the microgrooves 82m on the surface 821 of the outer layer is in the range of 0.2 to 1.0 μm, the decrease in the position detection accuracy of the calibration patch T due to the influence of groove processing defects can be more effectively suppressed.

[0168] Although the effect of suppressing the deterioration of detection accuracy can be obtained even if the depth of the microgrooves 82m on the surface layer 821 is made deeper than 1.0 μm, it is considered that if the grooves are too deep, surface cracks (breaks) are more likely to occur from the bottom of the grooves. For this reason, in this embodiment, it is preferable to limit the depth of the grooves 82m to 1 μm.

[0169] Furthermore, the results of Examples 5 and 7 showed that when the number of microgrooves 82m on the surface 821 of the surface layer is small and the depth is shallow, the degree of decrease in the position detection accuracy of the calibration patch T due to the influence of groove processing defects is small.

[0170] (Comparative Examples 3 and 4) In Comparative Example 3, similar to Comparative Example 1, the base layer 81 is not subjected to wrapping film processing, and the protruding interval of the mold 92 for imprint processing of the surface layer 82 is increased. In the configuration of Comparative Example 3, the amount of erroneous detection caused by groove processing defects is less than 80 μm, which is acceptable.

[0171] Furthermore, Comparative Example 4 is configured under the same wrapping film processing conditions for the base layer 81 as in Example 1, and does not perform imprint processing on the surface layer 82. In Comparative Example 4 as well, the amount of erroneous detection caused by groove processing defects is less than 80 μm, which is acceptable.

[0172] When the "20 degree gloss value" of the surface layer 82 was compared between Examples 1, 4, and 5 and Comparative Example 3, it was found that Comparative Example 3 had the highest 20 degree gloss value.

[0173] This is because, as in Examples 1, 4, and 5, Comparative Example 3 has a small number of grooves 82m in the surface layer 82, and thus there is little diffuse reflection due to the surface layer grooves. As a result, there is a tendency for specular reflection from the surface layer 82 to be stronger in Comparative Example 3. As a result, there is little "difference" in the amount of specular reflection light between the groove-processed defective portion and the normal portion, and therefore it is thought that in Comparative Example 3, there is little deterioration in position detection accuracy even without performing fine groove processing on the base layer 81.

[0174] The "20-degree gloss value" of Comparative Example 4 shows the highest value of "58" because no imprint processing was performed on the surface layer 82. In other words, it was found that in the "groove processing missing portion," if the groove depth were to be "0," the maximum value of the 20-degree gloss value of the surface layer 82 would be "58."

[0175] In this embodiment, the size of the groove-processed defect is 2 mm, making it difficult to directly measure the gloss value. Therefore, in Examples 1 to 7 of this embodiment and Comparative Examples 1 to 3, the total pressure during imprinting was reduced to obtain a belt with a groove depth equivalent to the groove-processed defect, and then the 20-degree gloss value was measured. As a result, the gloss value of the belt surface corresponding to the groove-processed defect was approximately 46 to 54.

[0176] Therefore, in the configuration of Comparative Example 3, in which the 20-degree gloss value of the imprinted surface layer 82 is 46, the difference in the amount of specularly reflected light between the groove-defective area and the normal area is small. For this reason, even if the groove-defective area and the position detection pattern overlap in the thickness direction, the change in the output waveform W of the optical sensor is small in the overlapping area, and it is thought that erroneous detection of the position detection pattern is unlikely to occur.

[0177] Furthermore, the results of Comparative Examples 3 and 4 showed that when the fine groove processing on the surface 821 includes a configuration without groove processing (number of grooves: 0 / mm) and the number of grooves 82m is less than 160 / mm, there is little decrease in the position detection accuracy of the calibration patch T due to the influence of the "groove processing missing parts."

[0178] Furthermore, the results of Example 7 and Comparative Examples 3 and 4 show that when the 20-degree gloss value of the outer layer surface 821 exceeds 40, the deterioration in position detection accuracy is small.

[0179] However, as can be seen from the friction resistance evaluation results of Comparative Examples 3 and 4, when the number of grooves 82m in the surface layer 82 is less than 160 / mm, the coefficient of friction with the cleaning blade becomes high, and there is a high possibility of defects such as blade squeal occurring.

[0180] As described above, in this embodiment, the number of grooves 82m formed by microgrooving on the surface of the upper layer 821 is preferably 80 to 500 grooves / mm in the width direction Z3. On the other hand, the number of grooves 81m formed by microgrooving on the surface of the base layer 811 must be 80 grooves / mm or more in the width direction Z3.

[0181] Furthermore, in a configuration in which the 20-degree gloss value in the imprinted area exceeds "40," the coefficient of friction for cleaning is similarly high, increasing the likelihood of blade squeal. Therefore, it is desirable that the 20-degree gloss value in the imprinted area be 40 or less. Furthermore, when the gloss value in the groove-defective area is greater than 40, the "difference" in the amount of specular reflection light between the groove-defective area and the normal area in the imprinted area is large, and it is thought that this will likely lead to a decrease in the accuracy of detecting the position of the calibration patch.

[0182] According to the present invention, it is possible to effectively suppress a decrease in the accuracy of detecting the position of a calibration patch due to groove defects in an intermediate transfer belt having micro-machined grooves on its surface. In other words, it is possible to maintain low surface friction resistance of the intermediate transfer belt and realize a configuration with high detection accuracy by an optical sensor.

[0183] The present invention can be summarized as follows.

[0184] (1) The intermediate transfer belt (8) of the present invention is An endless intermediate transfer belt having a first layer (81) and a light-transmitting second layer (82) provided in contact with a first surface (811) of the first layer that is located on the outer side of the intermediate transfer belt in use, The first surface of the first layer has a first groove (81m) extending in a first direction (Z1) along the circumferential direction (Z) of the intermediate transfer belt, a second surface (821) of the second layer located on the opposite side to the side on which the first layer is present, has a second groove (82m) extending in a second direction (Z2) along the circumferential direction; The first grooves are provided on the first surface at a density of 80 grooves / mm or more in the width direction (Z3) perpendicular to the circumferential direction.

[0185] (2) In the intermediate transfer belt of the present invention, The average groove depth (d1) of the first grooves (81m) can be set in the range of 0.2 to 0.5 μm.

[0186] (3) In the intermediate transfer belt of the present invention, The second grooves (82m) may be provided on the second surface (821) in the width direction (Z3) at a density of 160 to 500 grooves / mm.

[0187] (4) In the intermediate transfer belt of the present invention, The average groove depth (d2) of the second grooves (82m) can be set in the range of 0.2 to 1 μm.

[0188] (5) In the intermediate transfer belt of the present invention, The intermediate transfer belt (8) may be configured so that the gloss value at 20 degrees based on JIS Z8741 is 40 or less.

[0189] (6) In the intermediate transfer belt of the present invention, The second groove (82m) can be formed by an imprint process.

[0190] (7) In the intermediate transfer belt of the present invention, The first groove (81m) can be formed by wrapping film processing.

[0191] (8) In the intermediate transfer belt of the present invention, The average groove depth (d1) of the first grooves (81m) can be smaller than the average groove depth (d2) of the second grooves (82m).

[0192] (9) In the intermediate transfer belt of the present invention, The first direction (Z1) and the second direction (Z2) can be the same direction.

[0193] (10) The image forming apparatus (100) of the present invention is The intermediate transfer belt (8), an image forming means (P) for forming an image on an intermediate transfer belt; an optical sensor (27) for detecting an image formed on the intermediate transfer belt by the image forming means; It has.

[0194] (11) In the image forming apparatus of the present invention, The optical sensor (27) may be configured to detect a first region (275) having a predetermined width in the width direction (Z3) of the intermediate transfer belt (8) along the circumferential direction (Z) of the intermediate transfer belt, A first groove (81m) and a second groove (82m) may be formed in an area corresponding to the first area (275).

[0195] (12) In the image forming apparatus of the present invention, The second surface (821) of the second layer (82) may have, inside a region corresponding to the first region (275), a second region (102) in which the average groove depth (d2') of the second grooves (82m) is less than 0.2 μm; A first groove (81m) can be formed in the first surface (811) of the first layer (81) in an area corresponding to the second area (102).

[0196] (13) In the image forming apparatus of the present invention, In the second region (102), the intermediate transfer belt (8) may be configured so that the 20-degree gloss value based on JIS Z8741 is greater than 40. [Explanation of symbols]

[0197] 8 Intermediate transfer belt 81 Base layer (1st layer) 81m First Groove 811 First Surface 82 Surface layer (2nd layer) 82m Second groove 821 Second Surface Z rotation direction (circumferential direction) Z1 1st direction (circumferential direction) Z2 2nd direction (circumferential direction) Z3 Width direction

Claims

1. An endless intermediate transfer belt, The first layer, a second layer that is in contact with a first surface of the first layer that is positioned outside the intermediate transfer belt in use and that is capable of transmitting light; and the first surface of the first layer has a first groove extending in a first direction along the circumferential direction of the intermediate transfer belt; a second surface of the second layer located on the opposite side to the side on which the first layer is present has a second groove extending in a second direction along the circumferential direction; The intermediate transfer belt according to claim 1, wherein the first grooves are provided on the first surface at a density of 80 grooves / mm or more in a width direction perpendicular to the circumferential direction.

2. 2. The intermediate transfer belt according to claim 1, wherein the first grooves have an average depth in the range of 0.2 to 0.5 μm.

3. 3. The intermediate transfer belt according to claim 1, wherein the second grooves are provided on the second surface at a density of 160 to 500 grooves per mm in the width direction.

4. 4. The intermediate transfer belt according to claim 1, wherein the second grooves have an average depth in the range of 0.2 to 1 μm.

5. 5. The intermediate transfer belt according to claim 1, wherein the surface layer of the intermediate transfer belt has a gloss value of 40 or less at 20 degrees based on JIS Z8741.

6. 6. The intermediate transfer belt according to claim 1, wherein the average groove depth of the first grooves is smaller than the average groove depth of the second grooves.

7. 7. The intermediate transfer belt according to claim 1, wherein the first direction and the second direction are the same direction.

8. The intermediate transfer belt according to any one of claims 1 to 7, an image forming means for forming an image on the intermediate transfer belt; an optical sensor that detects an image formed on the intermediate transfer belt by the image forming means; An image forming apparatus comprising:

9. the optical sensor detects a first region of the intermediate transfer belt having a predetermined width in the width direction thereof along the circumferential direction of the intermediate transfer belt; 9. The image forming apparatus according to claim 8, wherein the first groove and the second groove are formed in an area corresponding to the first area.

10. the second surface of the second layer has a second region inside a region corresponding to the first region, in which the average groove depth of the second grooves is less than 0.2 μm; 10. The image forming apparatus according to claim 9, wherein the first groove is formed in the first surface of the first layer in an area corresponding to the second area.

11. 11. The image forming apparatus according to claim 10, wherein in the second region, the surface layer of the intermediate transfer belt has a 20-degree gloss value based on JIS Z8741 of greater than 40.

Images