JP2005216574A - High-frequency induction heating method, heating method of support body for electronic photograph photoreceptor, and heating method of electronic photograph photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent local concentration of an eddy current with a simple tooling change and to suppress the width of temperature irregularity to around 10°C in heating a plurality of kinds of metallic cylinder drums different in length by using high-frequency induction heating. <P>SOLUTION: This application is related to a method for heating a metallic cylinder drum by using high-frequency induction heating, and, for more detail, related to a method for heating a tubular support body for an electronic photograph photoreceptor and a tubular electronic photograph photoreceptor, and, for still more detail, a setup method in response to a cylinder length difference in high-frequency induction heating. In the application, a tool formed of the same material as that of the support body and having the same outside diameter as that thereof is attached to a photosensitive drum support body; and the total of the axial length of the tool and the length of the photosensitive drum support body is set equal to the length of a high-frequency current generation effective range of a high-frequency induction coil to prevent temperature irregularity due to local concentration of an eddy current. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of heating a metallic cylinder drum using high-frequency induction heating, and more particularly to a support for a cylindrical electrophotographic photosensitive member and a method for heating a cylindrical electrophotographic photosensitive member. More specifically, the present invention relates to a setup method for dealing with different cylinder lengths in high frequency induction heating.

  The metal cylinder drum referred to in the present invention relates to a support for an electrophotographic photosensitive member. The electrophotographic photosensitive member referred to in the present invention relates to a photographic system by a conventionally known organic photoconductor electrophotographic process.

  As a method for producing an electrophotographic photoreceptor, for example, when a cylindrical metal cylinder such as aluminum is used as a support, an electrophotographic photoreceptor coating medium using an organic solvent or the like is immersed on the surface of the cylinder, spray, roller, etc. In general, a method of obtaining an electrophotographic photosensitive member having a coating film of a photosensitive layer by coating with a coating means and drying and / or curing the coating film by heating.

Among the above production methods, as a heating method for drying and / or curing a coating film, a hot air heating drying method and a heating method using the principle of electromagnetic induction heating are known (Patent Documents 1, 2 and the like). However, the method of jetting hot air from the inner surface of the cylinder disclosed in Patent Document 1 performs internal heating with a rod-shaped hot air blowing device having a stroke longer than the length of the cylinder and accurately at a fixed position of the conveyor. It had to be moved up and down, and the automatic machine became complicated, resulting in an increase in the cost of the apparatus and a decrease in reliability. In addition, the induction heating method using an electromagnetic induction coil spirally wound around the outside of a cylinder disclosed in Patent Document 2 has a stroke longer than the length of the cylinder and the conveyor is fixed. The position had to be moved up and down with high precision, and the automatic machine was complicated, resulting in an increase in the cost of the apparatus and a decrease in reliability.
Japanese Patent Laid-Open No. 10-239868 JP-A-9-114111

  Therefore, the present inventors paid attention to a method using the principle of high-frequency induction heating as a method for heating the electrophotographic photosensitive member and its substrate. Specifically, as shown in FIG. 1, this method arranges a high-frequency induction heating coil having a bowl shape surrounded by a loop-shaped ring so as to surround a half circumference of the electrophotographic photosensitive drum support. The photosensitive layer coating film is dried and cured by applying a high-frequency current to the saddle-shaped coil and performing high-frequency induction heating while rotating the support. According to this method, compared with a general hot air drying method, since the coating film is heated from the support side, the evaporated solvent is easy to escape from the surface, and there is no adverse effect such as drying unevenness due to the deflected flow of hot air. In addition, the high-frequency induction heating method has many parts that are superior to the hot-air drying method, such as the speed to reach the set temperature and the low temperature unevenness. As described above, the heating method of the electrophotographic photosensitive member by high frequency induction heating using the loop-shaped saddle coil can realize a drying / curing apparatus that is inexpensive, simple, and excellent in quality. However, as a matter to be devised, it is necessary to precisely align the axial length of the photosensitive drum support and the effective range of high-frequency current generation in the height direction of the high-frequency induction coil for each product. The reason will be described below.

  FIG. 1 shows an example of a method for heating a cylindrical metallic support by high-frequency induction heating using a loop-shaped saddle coil. As shown in FIG. 1, a loop-shaped saddle-shaped coil for high-frequency induction heating is arranged so as to surround the half circumference of the electrophotographic photoreceptor support immediately after coating, and a high-frequency current is passed through the coil to support the support. The photosensitive layer coating film can be dried and cured by high frequency induction heating while rotating. Here, the axial length of the support must be the same as the high-frequency current generation effective range in the height direction of the high-frequency induction coil. The reason is that, as shown in FIG. 6, the end of the cylindrical metallic support is inside the current generation range of the high-frequency induction coil, so that eddy currents concentrate on the end of the cylindrical metal. The concentration effect of this eddy current is that when the support made of a metal base that is long in the axial direction is heated compared to the effective length of the loop-shaped saddle type high frequency induction coil, the temperature of the center of the support and the end of the support This results in markedly different temperature variations. On the other hand, if the support is too longer than the induction coil, eddy currents do not act on the protruding support and the temperature does not rise.

  On the other hand, the drying / curing temperature condition of the photosensitive layer coating to obtain a good quality electrophotographic photoreceptor is required to suppress the temperature unevenness range as much as possible, and the heating temperature unevenness of the support is large. Significantly deviates from the required drying / curing temperature conditions for the photosensitive layer coating film.

  However, the length of electrophotographic photosensitive drums varies depending on the image forming apparatus. As a general countermeasure for this problem, there is a method in which a high-frequency induction coil dedicated to each drum of different lengths is prepared and used by replacing it.

But,
The axial length of the photosensitive drum support and the effective range length of the high-frequency current generation in the height direction of the high-frequency induction coil are aligned each time depending on the product. It took time to adjust the position of the coil and the photosensitive drum support, and there was a difficulty in setting up the products with different lengths.

  In the present invention, a jig having the same material and the same outer diameter as the support is attached to the photosensitive drum support, and the total length of the jig in the axial direction and the length of the photosensitive drum support is the length of the high frequency current generation effective range of the high frequency induction coil. To be the same.

  As described above, according to the present invention, local concentration of eddy currents can be prevented by easy changeover, and the width of unevenness can be suppressed to about 10 ° C.

  In order to achieve the above object, in the present invention, among the methods for producing an electrophotographic photoreceptor using an aluminum cylindrical cylinder as a support, a method for heating and drying the coated photosensitive layer and the surface protective layer. In the method, a method characterized in that the coating film was heated and dried and cured from the heat generated by the heated support itself by using an electromagnetic induction coil without using hot air.

  In other words, the magnetic field generated by the electromagnetic induction coil is applied to the aluminum cylinder, which is the support for the photosensitive layer, and the support is directly heated by the action of the eddy current generated as a result. The principle of heating method by induction coil was used.

  Next, a method that can cope with different product lengths by simple, easy and easy setup change will be described in detail. First, as shown in FIG. 1, a cylinder is surrounded by a single electromagnetic induction coil within 180 degrees in a semicircular shape, and two pairs of upper and lower parts are prepared, and the longitudinal axis of the photosensitive drum support is provided as an axis. They are connected in parallel. Such a saddle-shaped coil is characterized in that it is formed in a single manner as in “one-stroke writing”, and is lightweight and easy to manufacture with high accuracy. Hereinafter, this coil is referred to as a “loop coil” for convenience.

  It is preferable that the shape of the loop-shaped coil is within 180 degrees of the outer peripheral semicircular shape of the support body, whereby the support body or coil to be heated is heated in the radial direction of the support body in the heating process section of the conveyor of the manufacturing apparatus For example, a single support line shown in FIG. 5 can be used to convey the support continuously and without stagnation.

  Further, since the loop-shaped coil is lightweight and easy to manufacture with high precision, it can be slid close to the outer surface of the support body, to the vicinity of 1 mm in the limit. At this time, if the distance between the coil and the support exceeds 10 mm, the eddy current generated from the lines of magnetic force due to electromagnetic induction is remarkably reduced. Therefore, the distance between the coil and the support is preferably 10 mm or less.

  It is preferable to attach a copper plate to both inner sides of the coil because heating efficiency can be increased. Furthermore, it is preferable to connect a pipe or the like through which cooling water is passed to the coil, because it is possible to precisely adjust the temperature and to prevent excessive temperature rise due to thermal runaway.

  Next, a setup method corresponding to different lengths, which constitutes the skeleton of the present invention, will be described with reference to FIG. 1, FIG. 2, FIG. 3, and FIG.

  First, as shown in FIG. 1, the maximum length of the high-frequency current generation range of the loop coil is adjusted to the longest drum among the types of photosensitive drum supports to be heated. Next, a length adjusting member having the same material and the same outer diameter as the photosensitive drum support whose axial length is shorter than that of the loop coil is actually manufactured. At that time, as shown in FIG. 2, the total length of the adjusting member in the axial direction and the length of the photosensitive drum support to be heated are set to be the same as the effective range of the high frequency current generation of the high frequency induction coil. The manufactured length adjusting member is inserted into the end of the support made of a metal base as shown in FIG. 2, and the combined length of the support and the inserted member is the dimension in the longitudinal direction of the coil. To be the same.

  Thereafter, the support is subjected to high-frequency induction heating, and it is confirmed that the temperature distribution error is within a specified range. With the above procedure, the setup for handling different lengths is completed.

  Next, the insertion place of the length adjusting member will be described. In order to prevent local concentration of eddy currents as shown in FIG. 6, it is desirable to insert the length adjusting member on the opposite side of the support reference surface in the axial direction as shown in FIG. In the insertion position of FIG. 3, the total length of the member and the support may be longer than the effective length of the coil.

On the other hand, as shown in FIGS. 2 and 4, when the length adjusting member is attached to the axial mounting reference surface of the support, the support is used to prevent the eddy current from being concentrated locally. Keep out of the effective range. As described above, the mounting location of the support is the same in principle regardless of whether it is inserted on the axial mounting reference plane or on the opposite side, but considering the versatility of the loop coil, From the viewpoint of distribution characteristics, it is preferable to insert the length adjusting member into the opposite side of the reference mounting surface in the axial direction of the photosensitive drum support as shown in FIG. However, if the dimensions have been adjusted properly, the workability is better when the members in FIGS. 2 and 4 are on the lower side.
(Example)

  Next, examples of the present invention will be described. An apparatus for heating the support was configured as follows, and apparatus conditions were set.

  As an electromagnetic induction coil, an IH coil manufactured by Nippon Thermonics Co., Ltd. was used, and PID control (a central value of 75 volts and 30 amps) was performed so as to be maintained at 150 ° C. A high frequency power supply was used and the frequency was set to 50 KHZ. The coil was a “loop coil” as shown in FIG. 1 and produced with an effective length of 370 mm for generating a high-frequency current.

  The cylinder is surrounded by 180 degrees by the coil, and the coil is bonded with a copper plate on both sides of the coil to increase the heating efficiency, and the distance between the copper plate and the support cylinder can be adjusted within a range of 1 to 10 mm. In this example, 2 mm was used. Although not shown, the inside of the coil has a structure that allows cooling water to pass therethrough to prevent overheating due to thermal runaway. The support cylinder was allowed to rotate at 100 RPM.

  An aluminum cylinder having an outer diameter of φ84 mm, a length of 370 mm, and a wall thickness of 3.0 mm was prepared as a support. In Example 1, the axial length of the support and the high frequency current generation effective range length of the high frequency induction coil were made the same.

  A heating experiment was carried out using the above heating apparatus and support. FIG. 1 is a conceptual diagram showing a state in which a cylinder disposed in a heating device using a high-frequency electromagnetic induction coil is heated. In this state, heating was performed at a preset temperature of 150 ° C. As shown in FIG. 9, the temperature was measured using thermolabels attached to three locations on the cylinder, in the middle, and below. The result was 151 ° C. at the top, 150 ° C. at the inside, 149 ° C. at the bottom, and the width of the temperature unevenness was 2 ° C. The result of the obtained heating experiment is shown in FIG.

  In Example 2, when the axial length of the support is shorter than the effective range of the high-frequency current generation of the high-frequency induction coil, a jig having the same material and the same outer diameter as the support is attached to the support, The sum of the axial length and the length of the support was made to be the same as the effective range length of the high-frequency current generation of the high-frequency induction coil. Four types of jigs with different thicknesses were prepared, and temperature data for different thicknesses was taken.

  An aluminum cylinder having an outer diameter of φ84 mm, a length of 340 mm, and a wall thickness of 3.0 mm was prepared as a support.

  Next, four types of aluminum jigs with different thicknesses of 30 mm length, outer diameter of φ84 mm, and wall thicknesses of 21.0 mm, 24.0 mm, 27.0 mm, and 30.0 mm, respectively, are prepared and the length is adjusted. It was used as a member. The length adjustment member was inserted into the upper part of the support, which is the opposite side of the support axial direction mounting reference plane in the method shown in FIG.

  The above support and adjusting member were set in the same heating apparatus as in Example 1, and a heating experiment was performed for each thickness. 3 and 7 are conceptual diagrams in which a cylinder disposed in a heating device using a high-frequency electromagnetic induction coil is heated. In this state, heating was performed at a preset temperature of 150 ° C. As shown in FIG. 11, the temperature was measured using thermolabels attached to the top, middle and bottom of the cylinder. The results of Example 2 are shown in FIG. As is apparent from FIG. 12 and Table 1, the adjustment member having a thickness of 21 mm left good results.

  In Example 3, an electrophotographic photosensitive member was produced in the following manner.

  An aluminum cylinder having an outer diameter of φ84 mm, a length of 340 mm, and a wall thickness of 3.0 mm was prepared as a support. A layer having the following constitution was sequentially laminated and applied to this using a dip coating apparatus.

  (1) Conductive coating layer: A layer mainly composed of tin oxide and titanium oxide powder dispersed in a phenol resin, and has a film thickness of 18 μm.

  (2) Undercoat layer: A layer mainly composed of modified nylon and copolymer nylon, and has a thickness of 1.0 μm.

  (3) Charge generation layer: A layer mainly composed of a disazo pigment having absorption in the visible region dispersed in an acrylic resin, and has a film thickness of 0.2 μm.

  (4) Charge transport layer: A layer mainly composed of a hydrazone compound having hole transportability dissolved in a polycarbonate resin, and has a film thickness of 25 μm.

  After application, a jig having a length of 30 mm, an outer diameter of φ84 mm, and a thickness of 21.0 mm was prepared as a length adjusting member, and assembled to the upper part of the support. In this state, similarly to Example 2, it was dried by heating at a set temperature of 150 ° C. to form a film. The above coating and drying / curing were repeated four times to form a photosensitive layer composed of four layers. When the fourth charge transport layer was heat-dried, the surface temperature of the photoreceptor cylinder was measured.

  In this example, a non-contact infrared thermometer was used as the temperature measurement method, and the temperature distribution on the cylinder surface at the temperature measurement position shown in FIG. 13 was measured over time. As a precaution, the thermolabel used in the measurements of Examples 1 and 2 was calibrated before the measurement, and it was confirmed that the difference between the measured values was within the range of 5 ° C. Thereafter, the upper, middle and lower portions of the cylinder were measured every 20 seconds. The results of the heating experiment obtained are shown in FIG. Compared with the measured value of the thermolabel, the non-contact infrared thermometer is easily affected by the color and reflectivity of the surface of the object to be measured. As apparent from FIG. 14 and Table 2, a good temperature rise curve and temperature distribution could be obtained even when the photosensitive layer was coated.

(Comparative Example 1)
In Comparative Example 1, the same support as in Example 2 was used, and high-frequency induction heating was performed without attaching an adjustment member. As a result, as shown in FIG. 6, the upper end portion of the cylindrical metallic support is 30 mm below the current generation range of the high frequency induction coil, so that eddy currents concentrate on the cylindrical metal end portion. When the center temperature of the support was 150 ° C., the end of the support exceeded the measurement upper limit of 180 ° C. of the thermolabel. Presuming from the temperature rise curve, it seems that the temperature reached 200 ° C., and the temperature unevenness was 50 ° C., which was an undesirable result. The result of the obtained heating experiment is shown in FIG.

Conceptual diagram of a device that heats a support that is a metal substrate with an electromagnetic induction coil Dimensioning the length with a conceptual diagram with a length adjustment member attached to the bottom of the metal substrate Conceptual diagram with length adjustment member mounted on top of metal substrate Conceptual diagram with a length adjustment member attached to the bottom of the metal substrate Conceptual diagram of a single sink line Schematic diagram of localized eddy currents Conceptual view from the side with a heating and drying device Conceptual view from above with heating and drying equipment Schematic showing the temperature measurement position of the drum in Example 1 The graph which shows the measurement result of the drum temperature in Example 1 Schematic which shows the temperature measurement position of the drum in Example 2. FIG. The graph which shows the measurement result of the drum temperature in Example 2 Schematic showing the measurement position of the drum temperature in Example 3 The graph which shows the measurement result of the drum temperature in Example 3 The graph which shows the measurement result of the drum temperature in the comparative example 1

Claims (4)

  A method of heating a metal cylindrical body from the outside with a high-frequency electromagnetic induction heating device, wherein the outer periphery of the upper end portion and the lower end portion of the cylindrical body is respectively within 180 degrees in a semicircular shape using a single wire coil When the cylindrical body is heated using a high-frequency electromagnetic induction coil that surrounds and connects these upper and lower semicircular coils so as to face each other in parallel with the longitudinal axis of the support, A metal, characterized in that a length adjusting member is inserted into the portion so that the combined length of the cylindrical body and the inserted length adjusting member is equal to or longer than the longitudinal dimension of the coil A high frequency induction heating method for a cylindrical body.   The high frequency induction heating method according to claim 1, wherein an insertion place of the length adjusting member is on an opposite side of an axial mounting reference surface of the support.   A method for heating a support for an electrophotographic photosensitive member, comprising heating the support for an electrophotographic photosensitive member using the high-frequency induction heating method according to claim 1.   A method for heating an electrophotographic photosensitive member, comprising heating the electrophotographic photosensitive member using the high-frequency induction heating method according to claim 1.

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