Induction heating device and method for manufacturing electrophotographic photoreceptor

Abstract

To provide an induction heating device that can efficiently and uniformly heat a body to be heated, and can easily and quickly carry the body to be heated in and out of an induction heating coil.SOLUTION: An induction heating device inductively heats a cylindrical long workpiece 100, and includes a conveyance path on which the workpiece in which the longitudinal direction of the workpiece is held parallel to the vertical direction is conveyed. When one side of the conveyance path is a first side, and the opposite side of the first side across the conveyance path is a second side, n (n is an integer of 3 or more) heating conducting wires for generating induction current in a circumferential direction of the workpiece are arranged on each of the first side and second side in the longitudinal direction of the workpiece.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an induction heating device for induction heating a cylindrical heated object. The present disclosure also relates to a method for manufacturing an electrophotographic photoreceptor.

Background Art

[0002] An electrophotographic photoreceptor (hereinafter also referred to as a photosensitive drum) mounted in an electrophotographic apparatus generally has a photosensitive layer formed on a cylindrical metal base layer. Further, a method of forming a protective layer on the surface of the photosensitive layer and curing the protective layer by electron beam irradiation and heating to improve the durability of the photosensitive drum is known.

[0003] For heating the photosensitive drum, methods using hot air heating, light heating, and induction heating have been attempted. In particular, a method using induction heating is effective because it can heat in a short time. Induction heating is a heating method in which when a magnetic field changes across a conductive material, eddy currents are generated near the surface of the conductive material, and the heated object is heated by the Joule heat generated thereby. At this time, a magnetic field that hinders the change of the magnetic field is generated by the eddy currents flowing in the conductive material. In induction heating, only the conductive material is heated, and a material with a sufficiently low electrical conductivity is not heated even if it is within the magnetic field generation region.

[0004] Further, the amount of heat generated by the heated object varies depending on the relative permeability of the heated object. If the heated object is a material with a high relative permeability such as iron or nickel (ferromagnetic material), a large amount of eddy currents are generated even with a slight change in the magnetic field, and the amount of heat generated increases. Conversely, if the heated object is a material with a low relative permeability such as aluminum or copper (non-magnetic material), the amount of eddy currents generated is small, and the amount of heat generated is smaller than that of the ferromagnetic material.

[0005] Spiral coils are often used to heat cylindrical objects. This is because a spiral shape allows for the generation of a high-density magnetic field inside the coil, enabling highly efficient heating, and also generates circumferential eddy currents in the cylindrical object, allowing for uniform heating. However, when using spiral coils, there is a constraint that the object to be heated cannot be fed into the coil unless it is transported in the axial direction. Furthermore, in systems that grip and transport the object to be heated by only one end, it is necessary to configure a transport mechanism that allows the object to be fed into the coil from one end and returns it to the starting position after heating is complete. In the case of long objects to be heated, such as photosensitive drums, the length in the axial direction of the coil becomes long, which means that the stroke of the transport mechanism for loading and unloading the object into and out of the coil also becomes long, resulting in higher costs for constructing the transport mechanism or delays in transport.

[0006] Patent Document 1 discloses an induction heating coil that solves the constraint of transporting the object to be heated in the axial direction of the coil. The induction heating coil disclosed in Patent Document 1 is an induction heating coil in which the outer circumference of the upper and lower ends of the object to be heated is surrounded by a single-wire coil in a semicircular shape, and these upper and lower semicircular coils are connected parallel to the longitudinal direction of the object to be heated. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2005-216574 [Overview of the project] [Problems that the invention aims to solve]

[0008] In the induction heating coil described in Patent Document 1, the coils positioned at the upper and lower ends of the object to be heated are semicircular, allowing the object to be freely transported to the heating position from directions without coils. Furthermore, by positioning semicircular coils above the upper end and below the lower end of the object to be heated, and connecting these upper and lower semicircular coils with wires parallel to the longitudinal direction on the outside of the object to be heated, the object can pass through the induction heating coil. Therefore, the transport device can be constructed with a simple mechanism. However, in this heating coil, parts of the object to be heated other than the upper and lower ends are only induced and heated by the magnetic field generated by the current flowing through the wires parallel to the longitudinal direction of the object to be heated. Therefore, there is room for improvement in heating efficiency. In addition, eddy currents are generated in the longitudinal direction of the object to be heated, causing them to concentrate at the upper and lower ends and making it easier for the temperature to rise, which can prevent uniform heating of the object.

[0009] One aspect of this disclosure aims to provide an induction heating device that can efficiently and uniformly heat an object to be heated and that can easily and quickly load and unload the object to be heated into and out of an induction heating coil. Furthermore, other aspects of this disclosure relate to methods for manufacturing high-quality electrophotographic photoreceptors. [Means for solving the problem]

[0010] According to one aspect of this disclosure, An induction heating device for induction heating a cylindrical, elongated workpiece, comprising: a transport path through which the workpiece is transported, with its longitudinal direction parallel to the vertical; one side of the transport path designated as the first side, and the side opposite the first side designated as the second side; on each of the first and second sides, n heating wires (n being an integer of 3 or more) are arranged longitudinally along the workpiece to generate an induced current in the circumferential direction of the workpiece; n first connecting wires and n-1 second connecting wires connecting the ends of the heating wires on the first side and the heating wires on the second side; the kth heating wire (k being an integer of 1 or more and n-1 or less) from the vertically above the heating wires on the first side is designated as heating wire 1C(k); and the kth heating wire from the vertically above the heating wires on the second side is designated as heating wire 2 When C(k), heating wire 1C(k) and heating wire 2C(k) are connected by a first connecting wire 3C(k), heating wire 2C(k) and heating wire 1C(k+1) are connected by a second connecting wire 4C(k), the nth heating wire 1C(n) from vertically above the first heating wire and the nth heating wire 2C(n) from vertically above the second heating wire are connected by the nth connecting wire 3C(n) from vertically above the first connecting wire, and the first group of connecting wires consisting of n first connecting wires and the second group of connecting wires consisting of (n-1) second connecting wires are arranged vertically above the upper end of the workpiece or vertically below the lower end of the workpiece so as not to interfere with the workpiece being transported along the transport path.

[0011] Furthermore, according to a second aspect of this disclosure, a method for manufacturing an electrophotographic photoreceptor having a photosensitive layer on the circumferential surface of a cylindrical cylinder is provided, the method comprising the step of heating the cylinder using the induction heating device described above.

[0012] Furthermore, according to a third aspect of the present disclosure, an induction heating device is provided in which, among the n heating wires observed in one vertical cross-section of the induction heating device, the p-th heating wire from the vertically above (where p is an odd integer of 1 or more, or an even integer of 2 or more), or each of the p-th heating wire and the p+1-th heating wire, is fitted with a magnetic flux guiding member that surrounds the outer circumference opposite to the side facing the workpiece transport path and guides the leakage magnetic flux from the heating wire toward the workpiece being transported along the workpiece transport path.

[0013] Furthermore, according to a fourth aspect of the present disclosure, an induction heating device is provided in which the magnetic flux induction member is arranged with respect to the first heating wire group and the second heating wire group. [Effects of the Invention]

[0014] According to one aspect of this disclosure, an induction heating device can be obtained that can efficiently and uniformly heat the object to be heated, and that can easily and quickly load and unload the object to be heated into and out of the induction heating coil. According to a second aspect of this disclosure, a high-quality electrophotographic photoreceptor can be easily obtained. According to a third aspect of this disclosure, manufacturing costs due to an increase in the number of heating wires can be reduced, and the temperature distribution within a single workpiece can be reduced. Furthermore, according to a fourth aspect of this disclosure, the temperature distribution within a single workpiece can be minimized as much as possible. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view showing the induction heating coil in this embodiment. [Figure 2] This figure shows a front view of an induction heating coil using the induction heating coil of this embodiment, and an overview of the induction heating configuration. [Figure 3] This is a front view showing an induction heating coil and induction heating configuration according to Embodiment 1 of the present disclosure. [Figure 4] This is a front view showing an induction heating coil and induction heating configuration according to Embodiment 2 of the present disclosure. [Figure 5]A cross-sectional view showing an induction heating coil and an induction heating configuration according to Example 3 of the present disclosure. [Figure 6] An enlarged cross-sectional view showing an induction heating coil and an induction heating configuration according to Example 3 of the present disclosure. [Figure 7] A cross-sectional view showing an induction heating coil and an induction heating configuration according to Example 4 of the present disclosure. [Figure 8] An enlarged cross-sectional view showing an induction heating coil and an induction heating configuration according to Example 4 of the present disclosure.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments. FIG. 1 is a perspective view showing an induction heating apparatus in the present embodiment. As shown in FIG. 1, the induction heating apparatus of the present disclosure heats a cylindrical long workpiece 100 as a heating target. The induction heating apparatus includes a conveyance path 120 through which the workpiece 100 whose longitudinal direction is held parallel to the vertical direction is conveyed, n first heating conductors 111C(1) to (n) (corresponding to heating conductors 1C(1) to (n)), n second heating conductors 112C(1) to (n) (corresponding to heating conductors 2C(1) to (n)), n first connection conductors 113C(1) to (n) (corresponding to connection conductors 3C(1) to (n)), and (n - 1) second connection conductors 114C(1) to (n - 1) (corresponding to connection conductors 4C(1) to (n - 1)). n represents an integer of 3 or more. An electrophotographic photoreceptor can be manufactured using the induction heating apparatus. Specifically, an electrophotographic photoreceptor can be manufactured by heating a cylindrical cylinder having a photosensitive layer on its circumferential surface using the induction heating apparatus of the present disclosure.

[0017] One side of the transport path 120 is designated as the first side (the side indicated by arrow 111), and the opposite side is designated as the second side (the side indicated by arrow 112). In this case, the first heating wires 111C(1)~(n) are arranged on the first side, substantially parallel to the transport path 120 and substantially parallel to each other, and the second heating wires 112C(1)~(n) are arranged on the second side, substantially parallel to the transport path 120 and substantially parallel to each other.

[0018] The kth heating wire from the vertically above the first heating wire (where k is an integer between 1 and n-1) is designated as heating wire 111C(k), and the kth heating wire from the vertically above the second heating wire is designated as heating wire 112C(k). In this case, heating wire 111C(k) and heating wire 112C(k) are connected by the first connecting wire 113C(k). Furthermore, heating wire 112C(k) and heating wire 111C(k+1) are connected by the second connecting wire 114C(k). Furthermore, the nth heating wire 111C(n) from the vertically above the first heating wire and the nth heating wire 112C(n) from the vertically above the second heating wire are connected by the nth connecting wire 113C(n) from the vertically above the first connecting wire.

[0019] In other words, the heating wire 111C(k), connecting wire 113C(k), heating wire 112C(k), connecting wire 114C(k), heating wire 111C(k+1), connecting wire 113C(k+1), heating wire 112C(k+1), connecting wire 114C(k+1), heating wire 111C(n), connecting wire 113C(n), and heating wire 112C(n) are connected in a continuous sequence.

[0020] Furthermore, the input / output terminals 115 of the heating wire 111C(1) and the input / output terminals 116 of the heating wire 112C(n) are connected to the high-frequency power supply 122 via the matching circuit 121.

[0021] n first connecting wires 113C(1) to (n) are designated as the first connecting wire group, and (n-1) second connecting wires 114C(1) to (n-1) are designated as the second connecting wire group. In this case, the first and second connecting wire groups are positioned vertically above the upper end of the workpiece 100 or vertically below the lower end of the workpiece 100 so as not to interfere with the workpiece 100 when it is transported along the transport path 120.

[0022] In the example shown in Figure 1, the first group of connecting wires, consisting of connecting wires 113C(1) to 113C(n), is positioned vertically above the upper end of the workpiece 100. The second group of connecting wires, consisting of connecting wires 114C(1) to 114C(n-1), is also positioned vertically above the upper end of the workpiece 100. Therefore, in the example shown in Figure 1, the workpiece 100 can be loaded into the induction heating coil from either the side where the first group of connecting wires is located or the side where the second group of connecting wires is located, and unloaded from the other side. Even when this loading and unloading method is adopted, neither the first nor the second group of connecting wires interferes with the workpiece being transported along the transport path during loading and unloading. Furthermore, by adopting this loading and unloading method, it becomes possible to unload workpieces that have been induction heated and unload workpieces that will be induction heated next in parallel, thereby reducing the time required for loading and unloading.

[0023] The number n is determined comprehensively, taking into account the length of the workpiece 100, the required temperature distribution for the workpiece 100, heating efficiency, equipment size, and cost. When heating wires are arranged at high density in the longitudinal direction of the workpiece 100, the heating efficiency of the workpiece increases, and the difference between the workpiece temperature near the heating wires and the workpiece temperature near the unheated wires in the longitudinal direction of the workpiece decreases. However, as the number of heating wires increases, the number of connecting wires also increases, resulting in a larger coil size and higher manufacturing costs. Conversely, when heating wires are arranged at low density in the longitudinal direction of the workpiece, the coil size decreases and manufacturing costs decrease. However, the heating efficiency of the workpiece decreases, and the difference between the workpiece temperature near the heating wires and the workpiece temperature near the unheated wires in the longitudinal direction of the workpiece increases.

[0024] Furthermore, the distance between heating wires 111C and 112C, which are opposite each other across the transport path, is determined based on factors such as workpiece transport accuracy, the required temperature distribution for the workpiece, and heating efficiency. A shorter distance between heating wires 111C and 112C results in higher workpiece heating efficiency. However, this increases the temperature difference between the workpiece near the heating wires and the workpiece near the heating wires in the longitudinal direction of the workpiece, and also requires high workpiece handling accuracy. Conversely, a longer distance between heating wires 111C and 112C results in a smaller temperature difference between the workpiece near the heating wires and the workpiece near the heating wires in the longitudinal direction of the workpiece, thus reducing the required accuracy for workpiece handling. However, this reduces the heating efficiency of the workpiece.

[0025] Furthermore, to equalize the temperature distribution along the longitudinal direction of the workpiece, it is also effective to vary the spacing between adjacent heating wires 111C(k) and 111C(k+1), and between heating wires 112C(k) and 112C(k+1), along the longitudinal direction of the workpiece. By appropriately setting the longitudinal position of the workpiece relative to heating wires 111C and 112C, and the density of the spacing between the heating wires, the workpiece can be given a desired temperature distribution.

[0026] Figure 2 shows a front view of the induction heating coil and an overview of the induction heating configuration in this embodiment. The heating wires 111C(1)~(n) and 112C(1)~(n) are arranged approximately perpendicular to the longitudinal direction of the workpiece 100 so as to generate an induced current in the circumferential direction of the workpiece 100. Note that in Figure 2, the heating wires 112C(1)~(n) are hidden by the heating wires 111C(1)~(n) and are therefore not shown in Figure 2. The lengths of the heating wires 111C(1) to (n) are preferably designed so that the direction of the circumferential induced current of the workpiece 100 is not obstructed by the magnetic field generated by the currents flowing through the connecting wires 113C(1) to (n) and 114C(1) to (n-1). In other words, the lengths of the heating wires 111C(1) to (n) are preferably designed so that the workpiece 100 is sufficiently far from the connecting wires 113C(1) to (n) and 114C(1) to (n-1). The same applies to the lengths of the heating wires 112C(1) to (n).

[0027] If the direction of the circumferential induced current of the workpiece 100 is obstructed, it is effective to install metal components or ferrite to shield against the magnetic flux generated by the current flowing through the connecting wires 113C and 114C. Also, if temperature unevenness occurs in the circumferential direction, it is effective to rotate the workpiece 100. In this embodiment, only one workpiece is heated simultaneously by one induction heating coil, but as shown in Figure 3, the lengths of the heating wires 111C and 112C may be extended so that multiple workpieces can be heated simultaneously by one induction heating coil.

[0028] The workpiece 100 is placed on a workpiece holding member 101 made of a non-conductive material, and the workpiece holding member 101 is moved using a transport mechanism 102, thereby transporting the workpiece 100 into the induction heating coil 110. The input and output terminals 115 and 116 of the induction heating coil 110 are connected to a high-frequency power supply 122 via a matching unit 121. The high-frequency power supply 122 supplies a high-frequency current to the induction heating coil 110 according to an output command, thereby heating the workpiece 100 placed inside the induction heating coil 110.

[0029] Preferably, among the n heating wires observed in one vertical cross-section of the induction heating device, a magnetic flux induction member is placed on the p-th heating wire from the vertical top, or on each of the p-th heating wire and the (p+1)th heating wire. In other words, a magnetic flux induction member is placed on each of the first heating wire, the second heating wire, ..., the nth heating wire. Alternatively, it is preferable that a magnetic flux induction member is placed between each of the following: "the first heating wire and the second heating wire," "the third heating wire and the fourth heating wire," ..., "the (n-1)th heating wire and the nth heating wire." However, p represents an odd integer greater than or equal to 1, or an even integer greater than or equal to 2. The magnetic flux induction member surrounds the outer circumference of the heating wire on the side opposite to the workpiece transport path, and guides the leakage magnetic flux from the heating wire towards the workpiece being transported along the workpiece transport path. It is more preferable that the magnetic flux induction member is positioned relative to the first group of heating wires and the second group of heating wires. Examples of materials for the magnetic flux induction member include ferrite, permalloy, amorphous metals, and the like. [Examples]

[0030] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples. <Example 1> Under the induction heating configuration shown in Figure 2, a heating experiment was conducted using an induction heating coil 110a capable of heating four workpieces 100a to 100d arranged in a single line in the transport direction, as shown in Figure 3. The workpieces 100a to 100d were cylindrical, with an outer diameter of φ24 mm, an inner diameter of φ22.5 mm, and a length of 261 mm, and were made of aluminum alloy. The distance between adjacent workpieces was set to 60 mm in all cases. The induction heating coil 110a was constructed from a copper pipe with an outer diameter of φ8 mm and an inner diameter of φ6 mm. In the following description, the heating wire and connecting wire refer to the aforementioned copper pipe. In this embodiment, a single long copper pipe was bent and manufactured as a single unit.

[0031] As shown in Figure 3, on each side of the transport path through which the four workpieces 100a to 100d are transported, 10 horizontal heating wires 111C and 112C are arranged in the longitudinal direction of the workpieces, intersecting approximately perpendicular to the longitudinal direction of the workpieces. The lengths of the horizontal heating wires 111C(1) to (10) arranged in the longitudinal direction of the workpieces are approximately equal to the lengths of the horizontal heating wires 112C(1) to (10).

[0032] The ends of heating wire 111C and heating wire 112C are connected by connecting wire 113C or connecting wire 114C. The connecting wires 113C and 114C are positioned vertically above the workpiece being transported from one end of the transport path to the other, and are positioned approximately perpendicular to the transport direction of the workpiece (approximately perpendicular to the plane of the paper in Figure 3). The portions of heating wires 111C and 112C other than the horizontal portions (hereinafter also referred to as non-horizontal portions) have an angle θ with respect to the vertical direction so that the non-horizontal portions of adjacent heating wires do not come into contact with each other.

[0033] In this embodiment 1, as shown in Figure 3, when four workpieces 100a to 100d are arranged in a single line in the transport direction, the distance from the left end of the horizontal section of the heating wire 111C to the axial center of workpiece 100a is 152 mm. The length Ls of the horizontal portion of the heating wire 111C was set to 500 mm so that the distance from the right end of the horizontal portion of the heating wire 111C to the axis center of the workpiece 100d was 168 mm. Similarly, the length L of the horizontal portion of the heating wire 112C, which is not shown in Figure 3, is also relevant. s The length was set to 500mm. Each of the heating wires 111C(1) to (10) has a horizontal section, a first non-horizontal section (the part to the right of the right end of the horizontal section in Figure 3), and a second non-horizontal section (the part to the left of the left end of the horizontal section in Figure 3). The first and second non-horizontal sections of the heating wires 111C(1) to (10) are both set to an angle θ of 29° with respect to the vertical. The input / output terminal 115 of the heating wire 111C(1) and the input / output terminal 116 of the heating wire 112C(10) are each connected to the high-frequency power supply 122 via a matching transformer 121.

[0034] The vertical distance L from heating wire 111C(1) to heating wire 111C(10) H and the vertical distance L from heating wire 112C(1) to heating wire 112C(10) H The length was set to 253mm. The upper ends of the workpieces 100a to 100d were positioned 7 mm vertically higher than the axis center of the horizontal section of the heating wires 111C(1) and 112C(1), and the lower ends of the workpieces 100a to 100d were positioned 1 mm vertically lower than the axis center of the horizontal section of the heating wires 111C(10) and 112C(10). Furthermore, the pitches P1 to P9 between the 10 heating wires in the longitudinal direction of heating wires 111C and 112C were configured as shown in Figure 3. Specifically, the pitches P1 to P3 were configured to gradually increase in length, P3 to P6 to remain constant, P6 to P8 to gradually decrease in length, and P8 to P9 to remain constant.

[0035] Also, across the transport path, The inner dimensions of heating wire 111C(1) and heating wire 112C(1), The inner dimensions between heating wire 111C(m) and heating wire 112C(m) (m is an integer between 2 and 9), The inner dimensions of heating wire 111C(10) and heating wire 112C(10), All of them were configured to be 50mm in length.

[0036] The input and output terminals 115 and 116 of the induction heating coil 110a are connected to the high-frequency power supply 122 via a matching unit 121. By supplying a high-frequency current to the induction heating coil 110a using the high-frequency power supply 122, the workpieces 100a to 100d placed inside the induction heating coil 110a can be heated. In this embodiment 1, after placing the workpieces 100a to 100d inside the induction heating coil at the positions shown in Figure 3, the high-frequency current was set under the condition that the workpieces were heated from room temperature of 23°C to 120°C in 10 seconds.

[0037] The workpieces 100a to 100d are placed on workpiece holding members 101a to 101d made of PEEK (polyetheretherketone), a non-conductive and highly heat-insulating material. When the workpieces are heated, heat is transferred from the workpieces to the workpiece holding members by heat transfer. In this embodiment 1, the arrangement of the induction heating coil 110a and the workpieces 100a to 100d is set to take this heat transfer into account and ensure that the temperature of the workpieces in the longitudinal direction is uniform during heating. The workpieces 100a to 100d are transported into the induction heating coil 110a by moving the workpiece holding members 101a to 101d using the transport mechanism 102. The transport mechanism 102 is composed of a horizontally moving single-axis robot, and the workpiece holding members 101a to 101d are fixed to the moving stage of the horizontally moving single-axis robot with a resin member (not shown).

[0038] Furthermore, in this embodiment 1, as shown in Figure 3, aluminum members 103a to 103d with an outer diameter of φ30 are installed above each of the workpieces 100a to 100d, and the distance from the upper end of each workpiece to the lower end of each aluminum member is set to 12 mm. If the aluminum members 103a to 103d are not installed, with the arrangement of the induction heating coil 110a and workpieces 100a to 100d in this embodiment 1, a magnetic field will enter the upper end surface and upper inner surface of the workpiece, causing the temperature of the upper end of the workpiece to be higher than the temperature of the middle part of the workpiece. By installing the aluminum members 103a to 103d as shown in Figure 3, the magnetic flux can be shielded, and the rise in temperature of the upper end of the workpiece can be suppressed. Note that this aluminum member 103 is also effective when heating multiple workpieces of different diameters and lengths with the same induction heating coil. When the diameter or length of the workpiece changes, the magnetic field distribution near the top of the workpiece fluctuates, and the temperature at the top of the workpiece also fluctuates significantly. However, by changing the distance between the top of the workpiece and the bottom of the aluminum member 103, it is possible to adjust the magnetic field distribution and maintain a constant temperature at the top of the workpiece. In this embodiment 1, the outer diameter of the aluminum member was set to φ30 mm, but it is preferable to select the outer diameter according to the shape of the induction heating coil and the diameter of the workpiece to be heated.

[0039] Based on the configuration of this embodiment 1, workpieces 100a to 100d were heated, and the average temperature and temperature distribution within each workpiece after heating were measured using a thermal viewer. The results showed that the individual difference in the average temperature of the four workpieces was Δ1°C or less, and the temperature distribution within each workpiece was Δ5°C or less. "Individual differences in the average temperature of the four workpieces" refers to the difference between the average temperature of the workpiece with the highest average temperature among the four workpieces and the average temperature of the workpiece with the lowest average temperature among the four workpieces. "Temperature distribution within a single workpiece" refers to the difference between the highest and lowest temperatures of the workpiece with the largest difference between its highest and lowest temperatures among the four workpieces. Length L of the heating wires 111C and 112C of the induction heating coil 110a sBy fine-tuning the pitch P1 to P9 between heating wires, it is possible to further reduce the individual differences in the average temperature of the four workpieces and the temperature differences within a single workpiece. In this embodiment 1, the minimum configuration was adopted based on the required temperature accuracy.

[0040] <Example 2> A heating experiment was conducted using an induction heating coil 110b capable of heating two workpieces 100a and 100b, as shown in Figure 4. The distance between the two workpieces was 60 mm. In the following, the same parts of the implementation conditions and configuration as in Example 1 will be omitted from the explanation.

[0041] The induction heating coil 110b has 10 horizontal heating wires 111C and 112C arranged on each side of the transport path through which the two workpieces 100a and 100b are transported, with the horizontal sections of each heating wire intersecting the longitudinal direction of the workpiece at approximately right angles to the longitudinal direction of the workpiece. The lengths of the horizontal sections of the 10 heating wires 111C(1) to (10) arranged on each side in the longitudinal direction of the workpiece are approximately equal to the lengths of the horizontal sections of the heating wires 112C(1) to (10).

[0042] The end of heating wire 111C and the end of heating wire 112C are connected by connecting wire 113C or connecting wire 114C. The connecting wires 113C and 114C are positioned vertically above the workpiece being transported from one end of the transport path to the other, and are arranged in a direction approximately perpendicular to the transport direction of the workpiece (approximately perpendicular to the plane of the paper in Figure 4). It is preferable that the non-horizontal portions of the heating wires 111C and 112C are connected at an angle to the vertical so that the non-horizontal portions of adjacent heating wires do not come into contact with each other.

[0043] In this embodiment 2, as shown in Figure 4, when two workpieces 100a and 100b are arranged in a single line in the transport direction, the distance from the left end of the horizontal part of the heating wire 111C to the axial center of workpiece 100a is 36 mm. The length L of the horizontal portion of the heating wire 111C is set such that the distance from the right end of the horizontal portion of the heating wire 111C to the axis center of the workpiece 100b is 44 mm. sThe length was set to 140mm. The heating wire 112C, which is not shown in Figure 4, also has a horizontal section length L. s The length was set to 140mm. Each of the heating wires 111C(1) to (10) has a horizontal section, a first non-horizontal section (the part to the right of the right end of the horizontal section in Figure 4), and a second non-horizontal section (the part to the left of the left end of the horizontal section in Figure 4). The first and second non-horizontal sections of the heating wires 111C(1) to (10) are both set to an angle θ of 29° with respect to the vertical. The input / output terminal 115 of the heating wire 111C(1) and the input / output terminal 116 of the heating wire 112C(10) are each connected to the high-frequency power supply 122 via a matching transformer 121.

[0044] The vertical distance L from heating wire 111C(1) to heating wire 111C(10) H and the vertical distance L from heating wire 112C(1) to heating wire 112C(10) H The length was set to 245 mm. Workpieces 100a and 100b were set to have an outer diameter of φ24 mm, an inner diameter of φ22.5 mm, and a length of 261 mm, similar to Example 1. The upper ends of workpieces 100a and 100b were positioned 11 mm vertically higher than the axis center of the horizontal section of the heating wires 111C(1) and 112C(1), and the lower ends of workpieces 100a and 100b were positioned 5 mm vertically lower than the axis center of the horizontal section of the heating wires 111C(10) and 112C(10). Furthermore, as shown in Figure 4, the pitches P1 to P9 between the 10 heating wires in the longitudinal direction of heating wires 111C and 112C were configured such that pitches P1 to P5 were constant, pitches P5 to P8 gradually decreased, and pitches P8 to P9 remained constant.

[0045] Opposing each other across the transport path The inner dimensions of heating wire 111C(1) and heating wire 112C(1), The inner dimensions between heating wire 111C(m) and heating wire 112C(m) (m is an integer between 2 and 9), The inner dimensions of heating wire 111C(10) and heating wire 112C(10), All of them were configured to be 40mm in length.

[0046] In this second embodiment, after placing the workpieces 100a and 100b inside the induction heating coil 110b at the positions shown in Figure 4, the high-frequency current was set under the condition that the workpieces were heated from room temperature of 23°C to 120°C in 10 seconds.

[0047] In this embodiment 2, plate-shaped upper ferrites 104a and 104b were placed on the outside of the upper ends of the workpieces 100a and 100b, respectively, and plate-shaped lower ferrite 105 was placed on the inside of the lower ends. The dimensions and installation positions of the upper ferrite parts 104a and 104b are as follows. "size" Figure 4, viewed from the front Height: 35mm Width: 10mm Depth (perpendicular to the paper surface): 30mm 《Installation position》 Distance from the axis center of workpiece 100a to the right end of ferrite 104a: 20 mm Distance from the axis center of workpiece 100b to the left end of ferrite 104b: 20 mm Distance from the top edge of workpieces 100a and 100b to the top edge of ferrite 104a and 104b: 29 mm

[0048] The dimensions and installation locations of each part of the lower ferrite 105 are as follows: "size" Figure 4, viewed from the front Height: 10mm Width: 30mm Depth (perpendicular to the paper surface): 56mm 《Installation position》 Distance from the axis center of workpiece 100a to the left end of ferrite 105: 15 mm Distance from the axis center of workpiece 100b to the right end of ferrite 105: 15 mm Distance from the lower end of workpieces 100a and 100b to the upper end of ferrite 105: 2 mm

[0049] In this embodiment 2, the arrangement of the induction heating coil 110b and the workpieces 100a and 100b is such that the distance from workpiece 100b to connecting wire 113C and the distance from workpiece 100a to connecting wire 114C are short. The upper ferrites 104a and 104b are there to shield the magnetic field so that the direction of the induced current in the circumferential direction of the workpiece is not obstructed by the magnetic field generated by the current flowing through the connecting wires 113C and 114C.

[0050] Based on the configuration of this embodiment 2, workpieces 100a and 100b were heated, and the average temperature and temperature distribution within each workpiece after heating were measured using a thermal viewer. The results showed that the individual difference in the average temperature of the two workpieces was Δ1°C or less, and the temperature distribution within each workpiece was Δ10°C or less. This configuration is effective when handling two workpieces and when it is desirable to keep the induction heating coil as short as possible.

[0051] <Example 3> Heating experiments were conducted using four workpieces 100a to 100d with the induction heating coil 110a shown in Figure 3 and the magnetic flux induction member 131C shown in Figure 5. In the following, the same parts of the implementation conditions and configuration as in Example 1 will be omitted from the explanation.

[0052] Each of the 10 heating wires 111C(1) to (10) has a magnetic flux induction member 131C(1) to (10) placed around the outer circumference opposite to the side facing the workpiece transport path.

[0053] As shown in Figure 6, the magnetic flux induction member 131C has a groove-shaped cross-section with a flange width LF of 20 mm, a web height LW of 20 mm, and a thickness T of 2 mm, and a length of 220 mm. In this embodiment, one magnetic flux induction member is placed per heating wire, but the length of the magnetic flux induction member may be shortened and multiple magnetic flux induction members may be placed per heating wire. For example, instead of placing one magnetic flux induction member with a length of 220 mm, two magnetic flux induction members with a length of 110 mm may be placed. Ferrite was used as the material for the magnetic flux induction member.

[0054] The magnetic flux induction member is positioned on the side of the web opposite to the workpiece transport path, and its flanges are positioned so that their distance from the heating wires is approximately equal. In other words, the flanges of the magnetic flux induction member are positioned near the portion of the workpiece in the longitudinal direction where there are no heating wires. The magnetic flux induction member is supported by a resin member (not shown), and the distance LD between the center of the web thickness and the center of the workpiece can be set to any value.

[0055] A portion of the magnetic flux generated by the heating wire is generated on the opposite side from the workpiece transport path and therefore becomes leakage flux that does not contribute to heating the workpiece. By using a magnetic flux induction member to guide the leakage flux to the vicinity of the area without the heating wire in the longitudinal direction of the workpiece, the temperature difference between the area with the heating wire and the area without the heating wire in the longitudinal direction of the workpiece is reduced.

[0056] In this embodiment, after placing workpieces 100a to 100d in the positions shown in Figure 3, the high-frequency current was set under the condition that the workpieces were heated from room temperature of 23°C to 120°C in 10 seconds. Heating was performed while rotating each of the workpieces 100a to 100d.

[0057] Based on the configuration of this embodiment 3, workpieces 100a to 100d were heated, and the average temperature and temperature distribution within each workpiece after heating were measured using a thermal viewer. The results showed that the individual difference between the four workpieces was Δ1°C or less, and the temperature distribution within each workpiece was Δ4°C or less. This configuration is effective when it is desired to reduce manufacturing costs due to an increase in the number of heating wires and to minimize the temperature distribution within each workpiece.

[0058] <Example 4> Four workpieces 100a to 100d were heated using the induction heating coil 110a shown in Figure 3 and the magnetic flux induction members 131C and 132C shown in Figure 7. The following explanation of the implementation conditions and configuration is the same as in Example 3 and will be omitted.

[0059] Each of the 10 heating wires 111C(1) to (10) has a magnetic flux induction member 131C(1) to (10) placed around the outer circumference opposite to the side facing the workpiece transport path. In addition, each of the 10 heating wires 112C(1) to (10) has a magnetic flux induction member 132C(1) to (10) placed around the outer circumference opposite to the side facing the workpiece transport path.

[0060] As shown in Figure 8, the magnetic flux induction members 131C and 132C have a groove-shaped cross-section with a flange width LF of 20 mm, a web height LW of 20 mm, and a thickness T of 2 mm, and a length of 220 mm. In this embodiment, one magnetic flux induction member is placed per heating wire, but the length of the magnetic flux induction members may be shortened and multiple magnetic flux induction members may be placed per heating wire. Ferrite was used as the material for the magnetic flux induction members.

[0061] In this embodiment, after placing workpieces 100a to 100d in the positions shown in Figure 3, the high-frequency current was set under the condition that the workpieces were heated from room temperature of 23°C to 120°C in 10 seconds.

[0062] Based on the configuration of this embodiment 4, workpieces 100a to 100d were heated, and the average temperature and temperature distribution within each workpiece after heating were measured using a thermal viewer. The results showed that the individual difference between the four workpieces was Δ1°C or less, and the temperature distribution within each workpiece was Δ3°C or less. This configuration is effective when it is desirable to minimize the temperature distribution within each workpiece. [Explanation of Symbols]

[0063] 100 Work 101 Coil holding member 102 Conveying mechanism 103 Aluminum component 104 Upper ferrite 105 Lower ferrite 110 Induction heating coil 111C, 112C heating conductor 113C, 114C connecting wires 115, 116 input / output terminals 121 Matching box 122 Power supply 131C, 132C Magnetic flux induction member

Claims

1. An induction heating device for induction heating a long cylindrical workpiece, a conveying path along which the workpiece is conveyed, the workpiece being held with its longitudinal direction parallel to the vertical direction; When one side of the transport path is defined as a first side and the opposite side of the transport path to the first side is defined as a second side, n heating conductors (n is an integer of 3 or more) that generate an induced current in the circumferential direction of the workpiece are arranged in the longitudinal direction of the workpiece on each of the first side and the second side, a number n of first connecting wires and a number n-1 of second connecting wires connecting the ends of the first-side heating wire and the second-side heating wire; When the kth heating conductor (k is an integer of 1 or more and n-1 or less) from the vertically upper side of the first side heating conductor is defined as heating conductor 1C(k) and the kth heating conductor from the vertically upper side of the second side heating conductor is defined as heating conductor 2C(k), The heating conductor 1C(k) and the heating conductor 2C(k) are connected by a first connecting conductor 3C(k), The heating conductor 2C(k) and the heating conductor 1C(k+1) are connected by a second connecting conductor 4C(k), The n-th heating conductor 1C(n) from the vertically upper side of the first heating conductor and the n-th heating conductor 2C(n) from the vertically upper side of the second heating conductor are connected by the n-th connecting conductor 3C(n) from the vertically upper side of the first connecting conductor, An induction heating device characterized in that a first connection wire group consisting of n first connection wires and a second connection wire group consisting of (n-1) second connection wires are arranged vertically above the upper end of the workpiece or vertically below the lower end of the workpiece so as not to interfere with the workpiece being transported along the transport path.

2. A method for producing an electrophotographic photoreceptor having a photosensitive layer on a peripheral surface of a cylindrical cylinder, comprising the steps of: A method for producing an electrophotographic photoreceptor, comprising the step of heating the cylinder with the induction heating device according to claim 1.

3. The induction heating device described in claim 1, wherein, of n heating conductors observed in a vertical cross section of the induction heating device, the pth heating conductor (wherein p is an odd integer of 1 or greater, or an even integer of 2 or greater) from the top vertically, or the pth heating conductor and the p+1th heating conductor, are each provided with a magnetic flux induction member that surrounds the outer periphery on the side opposite to the side facing the conveying path and induces leakage magnetic flux from the heating conductor toward the workpiece being conveyed along the conveying path.

4. 4. The induction heating device of claim 3, wherein the magnetic flux guider is disposed relative to the first side heating conductor group and the second side heating conductor group.

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