JP2006215347A - Method for manufacturing electrophotographic photoreceptor drum unit, process cartridge and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an electrophotographic photoreceptor drum unit having good cylinder run-out accuracy by preventing dislocation of a shaft axis at the time of working a shaft portion in a similar circle by preventing decentering in rotation, a process cartridge giving a good image free of density unevenness and color shift because of little irregularity in peripheral speed, and an electrophotographic apparatus. <P>SOLUTION: The method for manufacturing the electrophotographic photoreceptor drum unit composed of an electrophotographic photoreceptor drum and an engagement member having a shaft portion includes a step of connecting the engagement member to the photoreceptor drum, measuring imbalance amount in rotational weight, and adjusting dynamic mass eccentricity distance in the connected shaft portion to ≤25 μm, and a step of rotating the photoreceptor drum to which the engagement member has been connected and working the shaft portion of the connected engagement member in a similar circle with the periphery-based central axis of the photoreceptor drum as the center. The process cartridge with the photoreceptor drum unit and the electrophotographic apparatus are also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a high-precision electrophotographic photosensitive drum unit used in an electrophotographic apparatus such as an electrophotographic copying machine, a laser beam printer, and a facsimile printing machine, and a process cartridge including the electrophotographic photosensitive drum unit. And an electrophotographic apparatus.

  An image forming apparatus employing an electrophotographic system such as a copying machine or a laser beam printer, a so-called electrophotographic apparatus, includes an electrophotographic photosensitive member, a charging unit for charging the peripheral surface of the electrophotographic photosensitive member, and a charged electron An exposure means for forming an electrostatic latent image on the peripheral surface of the photographic photosensitive member and an electrostatic latent image formed on the peripheral surface of the electrophotographic photosensitive member are developed with a developer carried on the developer carrying member. Generally, a developing unit for forming a developed image and a transfer unit for transferring the developed image formed on the peripheral surface of the electrophotographic photosensitive member to a transfer material (paper or the like).

  In such an electrophotographic apparatus, as shown in FIG. 1, an electrophotographic photosensitive drum unit 101 (hereinafter referred to as “electrophotographic photosensitive drum unit”) generally includes an electrophotographic photosensitive drum (photosensitive layer on a cylindrical substrate). 103) and engaging members 104 and 105 provided at both ends or one end of the electrophotographic photosensitive drum.

  The engaging member generally has a flange or a gear-like driving force receiving means, which is also called a gear, and is connected to the electrophotographic photosensitive drum at the outer periphery (cylindrical coupling portion) of the engaging portion. A bearing portion (hereinafter, also referred to as “shaft portion” including “shaft portion” and “shaft bearing”), and an electrophotographic photosensitive drum unit is provided in the electrophotographic apparatus through the shaft portion. It has a support at a position, receives a driving force from a driving means, and has a function of rotating the electrophotographic photosensitive drum around a predetermined axis 108 with high accuracy. If the cylindrical accuracy of the electrophotographic photosensitive drum unit is not good, or if the shaft is decentered (for example, the shaft center is 109), the electrophotographic photosensitive drum unit is incorporated into the electrophotographic apparatus and rotated. The distance between the electrophotographic photosensitive drum and the developing means 110 cannot be kept constant, for example, the outer periphery of the photosensitive drum unit is shaken during image formation, and image density unevenness occurs during development, and a good image cannot be obtained. Furthermore, since unevenness occurs in the peripheral speed of the outer periphery of the electrophotographic photosensitive drum unit, an image shift (particularly a phenomenon in which the transfer position shifts in a color image and the color blurs) occurs during transfer and the like, and a good image is obtained. The problem of not happening. Therefore, in the electrophotographic photosensitive drum unit, in particular, the cylindrical swing accuracy (the difference between the coaxial outer circumscribed cylindrical diameters of the maximum outer peripheral portion and the minimum outer peripheral portion when rotating with reference to the rotation shaft of the electrophotographic photosensitive drum unit, “JIS-B0021”. It is necessary to reduce the value of “18.16.1 total runout tolerance”.

  In a monotone and low resolution electrophotographic apparatus, the cylindrical swing accuracy is about 100 μm and there is no problem. However, in recent years, the electrophotographic apparatus has been improved in resolution and full color, and the electrophotographic photosensitive drum unit has high precision. It is required to be. Further, in the electrophotographic apparatus for color, a plurality of electrophotographic photosensitive drum units are arranged, and tandem type electrophotography using a different electrophotographic photosensitive drum unit for each of yellow, cyan, magenta and black toners. An apparatus has been developed, and high accuracy is required for the electrophotographic photosensitive drum unit. In an electrophotographic apparatus with high resolution and full color, particularly high accuracy is required for the electrophotographic photosensitive drum unit.

  In the method of manufacturing a high-precision electrophotographic photosensitive drum unit, as a conventional method of manufacturing a cylindrical substrate, for example, an aluminum alloy is extruded and processed into a cylindrical shape by a method such as drawing, the cylindrical accuracy is increased by a correction means, The method of cutting to length is mentioned. Furthermore, a method for finishing the outer peripheral surface of the member manufactured by the above method by cutting (for example, see Patent Document 1) has been developed. This method is generally called lathe processing, and for example, the central axis of the cylindrical base is rotated while being kept constant, and a cutting tool is applied to the outer periphery of the cylindrical base at a constant speed parallel to the central axis. It is a method of cutting while feeding. However, even when manufactured by the above-described method, the inner core and the outer core of the cylindrical base do not coincide with each other, and the uneven thickness is about several μm to several tens of μm (nonuniform thickness of the cylindrical base). ) Is often present. Furthermore, a method for producing an electrophotographic photosensitive drum unit using only a high-precision cylindrical substrate by selecting a cylindrical substrate with accuracy during the manufacturing process is also known, but it is avoided that the cost is increased. Absent.

  When the engaging member is joined to the electrophotographic photosensitive drum having a large thickness deviation and the center of the outer periphery does not coincide with the center of the inner periphery, the center of the shaft of the engaging member and the outer peripheral center of the electrophotographic photosensitive drum are aligned. The outer circumference of the electrophotographic photosensitive drum unit rotates eccentrically and does not necessarily match, causing image defects. For this reason, a method of processing the inner periphery of the joint portion with the engaging member of the cylindrical base body on the basis of the outer periphery of the cylindrical base body (for example, see Patent Document 2) is performed. It is inevitable that the processing time increases and the cost increases.

  Many conventional engaging members are manufactured by molding a resin. In the case of such a manufacturing method, deformation due to shrinkage or the like after molding cannot be avoided, and the center of the outer periphery of the engaging member and the center of the shaft do not match and have variations. Therefore, in order to increase the cylindrical swing accuracy, for example, it is common to perform cutting on the outer peripheral portion with the shaft center as a reference to increase the dimensional accuracy of the flange and the concentricity between the outer periphery and the shaft. However, when such a process is performed, it is inevitable that the cost of the engaging member increases. Furthermore, it is necessary to join the electrophotographic photosensitive drum and the engaging member with high accuracy. That is, conventionally, as a method for obtaining an electrophotographic photosensitive drum unit in which the outer peripheral reference central axis of the support of the electrophotographic photosensitive member coincides with the central axis of the shaft portion, that is, the rotational accuracy is high, (A) accuracy is A high support or engagement member is manufactured, and the engagement member is engaged with the end of the support by a more precise joining technique (see, for example, Patent Document 2).

  On the other hand, (B) a method of joining at an angle that cancels the eccentricity of the electrophotographic photosensitive drum and the engaging member (see, for example, Patent Document 3) is also known, but the capital investment is large and the production efficiency is lowered. High costs are inevitable. As described above, there is a problem that a high-precision electrophotographic photosensitive drum, an engaging member, and a high joining technique are required, resulting in high costs.

  As another method for obtaining an electrophotographic photosensitive drum unit with high rotational accuracy, (C) after engaging an engagement member with the end of the electrophotographic photosensitive drum, the outer peripheral reference center of the electrophotographic photosensitive drum There is a method of processing the shaft portion so as to be concentric with the shaft. This method can provide an electrophotographic photosensitive drum unit with high rotational accuracy even if the accuracy of the electrophotographic photosensitive drum and the engaging member is relatively lower than the above two methods (A) and (B). This method is advantageous in terms of manufacturing costs. It is possible to easily process the surface of the shaft portion into a similar circular shape around the center axis of the outer periphery of the electrophotographic photosensitive drum without a costly process such as accuracy measurement using a simple device.

  Specifically, as shown in FIG. 2, a plurality of support rollers 201a, 201b, 202a, 202b, 203a and 203b are arranged so as to avoid the image area of the electrophotographic photosensitive drum. An object 101 (an electrophotographic photosensitive drum coupled with an engaging member, which becomes an electrophotographic photosensitive drum unit after processing) is supported. Next, by driving the support rollers 203 a and 203 b, the workpiece is rotated about the outer peripheral reference central axis 108 of the electrophotographic photosensitive drum 102. Next, by pressing the cutting members 204 and 205 against the shaft portions 106 and 107 of the engaging members 104 and 105 of the rotating workpiece 101, a central axis that is concentric with the outer peripheral reference central axis 108 of the electrophotographic photosensitive member 102. Can be applied to the shaft portions 106 and 107 (hereinafter, a series of processing is referred to as “centering processing”). 2 illustrates the processing of the “shaft”, but the processing of the “bearing portion” can be performed in the same manner.

  However, in the method of manufacturing the electrophotographic photosensitive drum unit as described above, there is an advantage that a high-precision electrophotographic photosensitive drum unit can be obtained at a low cost, while the electrophotographic photosensitive drum is processed with the engagement member coupled thereto. If there is a weight imbalance (weight imbalance) in the object, a centrifugal force is generated by the rotation, and the rotation shaft is biased or shaken, so that the shaft portion becomes a similar circle around the center axis of the electrophotographic photosensitive drum outer circumference reference. Even if it tried to process, the axis center shifted | deviated and the problem that the drum unit of the favorable cylindrical swing precision was not obtained occurred. Even if the electrophotographic photosensitive drum unit in which the deviation of the axis center occurs is incorporated in the electrophotographic apparatus and rotated, the outer periphery of the electrophotographic photosensitive drum unit is shaken during image formation, and the distance between the electrophotographic photosensitive drum and the developing unit is increased. Cannot be kept constant, resulting in a problem that uneven image density occurs and a good image cannot be obtained.

  Since the weight unbalance during rotation (rotational weight imbalance) is proportional to the square of the rotational speed, the rotational speed of the workpiece during shaft processing cannot be increased, and the machining time and cost are increased. Has occurred.

Furthermore, if the rotating weight balance is broken, the vibration increases, and the dimensional accuracy of the shaft portion and the surface roughness of the shaft portion decrease, so that sufficient accuracy can be obtained stably when supported in the electrophotographic apparatus. The problem of not occurring. Furthermore, if there is a large load bias, resonance vibration may occur depending on the rotational speed, and extremely large vibration may occur. Such resonance vibration may shorten the life of the processing equipment or sometimes damage the processing equipment. Was generated.
JP 2002-169421 A Japanese Patent Laid-Open No. 11-242407 JP 2002-91233 A

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and by rotating an electrophotographic photosensitive drum coupled with an engaging member, the shaft portion of the engaging member is set to the central axis of the electrophotographic photosensitive drum outer circumference reference. In the manufacturing method of an electrophotographic photosensitive drum unit having a process of rotating as a center and processing into a similar circle, the shaft center shifts when the shaft is processed into a similar circle by preventing the rotation center from being biased. It is an object of the present invention to provide a method for manufacturing an electrophotographic photosensitive drum unit having good cylindrical swing accuracy so as to prevent the occurrence of the above.

  Another object of the present invention is that the electrophotographic photosensitive drum unit manufactured by the above method has an outer periphery that does not shake when an image is formed by being incorporated in an electrophotographic apparatus, and the distance between the electrophotographic photosensitive drum and the developing means is reduced. An object is to provide a process cartridge and an electrophotographic apparatus which can be kept constant and can obtain a good image free from image density defects such as density unevenness and color misregistration due to less peripheral speed unevenness.

  According to the present invention, there is provided a method of manufacturing an electrophotographic photosensitive drum unit including at least an electrophotographic photosensitive drum and an engaging member having a shaft portion, and after the engaging member is coupled to the electrophotographic photosensitive drum, A step of measuring a rotational weight imbalance and setting a dynamic eccentric gravity center distance in the combined shaft portion within 25 μm; and an engagement coupled by rotating the electrophotographic photosensitive drum coupled with the engagement member And a step of processing the shaft portion of the member into a similar circle centering on the center axis of the outer periphery of the electrophotographic photosensitive drum. A method for manufacturing an electrophotographic photosensitive drum unit is provided.

  In addition, according to the present invention, there are provided a process cartridge and an electrophotographic apparatus including the electrophotographic photosensitive drum unit obtained by the above-described method for manufacturing an electrophotographic photosensitive drum unit.

  According to the method of manufacturing the electrophotographic photosensitive drum unit of the present invention, the electrophotographic photosensitive drum coupled with the engaging member is rotated to rotate the shaft portion of the engaging member around the central axis of the electrophotographic photosensitive drum outer circumference reference. In a method of manufacturing an electrophotographic photosensitive drum unit having a step of processing into a similar circle, the center of rotation is prevented from being biased to prevent deviation of the shaft center in the step of processing the shaft into a similar circle. A drum unit having a cylindrical swing accuracy can be manufactured stably.

  Furthermore, the electrophotographic photosensitive drum unit manufactured by the above-described method can maintain a constant distance between the electrophotographic photosensitive drum and the developing unit without shaking the outer periphery when image formation is performed by being incorporated in an electrophotographic apparatus. Furthermore, since there is little unevenness in the outer peripheral speed, a good image free from density unevenness and color shift can be obtained.

  Furthermore, when machining the shaft part into a similar circle, vibration due to rotation can be suppressed, the dimensional accuracy of the shaft part and the surface roughness of the shaft part can be prevented from being lowered, and further the generation of resonance vibrations can be prevented. Does not shorten the service life or damage the processing equipment.

  Furthermore, it is possible to provide a manufacturing method for an electrophotographic photosensitive drum unit having an extremely high cylindrical swing accuracy at a low manufacturing cost including capital investment, and also to greatly reduce the defect occurrence rate. In the manufacturing method of the electrophotographic unit, if the accuracy of the outer periphery of the electrophotographic photosensitive drum is good, other accuracy, for example, thickness deviation of the cylindrical substrate, concentricity, dimensional accuracy of the cylindrical substrate inner diameter portion, Roundness, eccentricity of the shaft of the engaging member or the bearing part, dimensional accuracy, roundness, surface roughness dimensional accuracy of the cylindrical coupling portion of the engaging member, when assembling the electrophotographic photosensitive drum and the engaging member The coaxiality and dimensional accuracy between the shaft portion and the outer periphery of the cylindrical substrate are greatly relaxed, and can greatly contribute to the improvement in performance and cost of the process cartridge and the electrophotographic apparatus.

The steps of the electrophotographic photosensitive drum unit manufacturing method of the present invention include:
(1) a step of coupling an engaging member to the electrophotographic photosensitive drum;
(2) a step of measuring rotational weight imbalance and setting a dynamic eccentric gravity center distance within 25 μm;
(3) A step of rotating around the center axis of the electrophotographic photosensitive drum outer circumference reference and processing the shaft portion of the engaging member into a similar circle having the same center axis as the center axis of the electrophotographic photosensitive drum outer circumference reference. ,
Have The rotational weight imbalance measurement in the above step (2) does not need to be performed for all the pieces and can be omitted if the design is the same as that for which the balance is confirmed. Furthermore, as a result of measuring the rotational weight imbalance, it is possible to add a step of selecting or adjusting the work piece by the rotational weight balance so that the dynamic eccentric gravity center distance is within 25 μm.

In the rotational weight imbalance measurement of the workpiece used in the method for producing the electrophotographic photosensitive drum unit of the present invention, it is necessary to measure the dynamic imbalance. The static (stationary) weight unbalance amount Us is the distance between the position where the unbalanced mass exists from the center of the rotation axis because gravity acts only on the unbalanced mass m (unbalanced mass existing in the workpiece). It can be expressed by the product of r, ie Us = mr, and it is sufficient to measure the weight imbalance by placing the work piece on a table that can freely rotate in the circumferential direction. However, in the case of a rotating body, a centrifugal force acts on the unbalanced mass m to generate an unbalance. In the present invention, it is necessary to measure a dynamic (rotating) rotational weight balance. The dynamic weight unbalance amount Ud is obtained by multiplying the distance r of the position where the unbalanced mass m and the unbalanced mass (unbalanced load) from the center exist by the square of the rotational speed w, and Ud = mrw ² It is necessary to measure the rotational weight imbalance while rotating at the same rotational speed as the subsequent step of processing the shaft portion into a similar circle. A value obtained by dividing the dynamic weight unbalance amount Ud by the mass M of the rotating body can be represented by the eccentric gravity center distance E. The dynamic eccentric center-of-gravity distance E is approximately equal to the deviation of the central axis when rotating by axial machining around the central axis of the outer periphery of the electrophotographic photosensitive drum.

That is, the electrophotographic photosensitive drum unit having good accuracy of the present invention is obtained by imbalanced rotational weight so that the dynamic eccentric gravity center distance E = Ud / M = mrw ² / M and the dynamic eccentric gravity center distance E ≦ 25 μm. Can be manufactured. Furthermore, since dynamic weight unbalance causes a problem even when the left and right axes are different from each other, it is necessary to balance rotational weight at both ends (two surfaces). When the workpiece has a mass deviation (weight imbalance), that is, when the dynamic eccentric center-of-gravity distance E exceeds 25 μm, centrifugal force is generated by the rotation, and the axis of rotation is biased or shaken, and the shaft part is electrophotographic photosensitive drum. Even if an attempt is made to process a similar circle around the central axis of the outer periphery reference, the axis is displaced, and an electrophotographic photosensitive drum unit with good cylindrical swing accuracy cannot be obtained.

  As a method for measuring the dynamic weight unbalance amount in the present invention, a known unbalance measurement method or apparatus can be used. FIG. 3 shows an example of the configuration of an apparatus for measuring the dynamic weight imbalance amount. The shaft portions 106 and 107 of the engaging member 301 of the workpiece (the electrophotographic photosensitive drum coupled with the engaging member) 301 in which the engaging members 104 and 105 are assembled to the electrophotographic photosensitive drum 102 are used as bearings of the measuring apparatus. Vibration detectors 304 and 305 are installed on bearings 302 and 303 received by 302 and 303, respectively. Examples of the vibration detector include an electrostatic capacity method and an eddy current method, and examples include detecting speed, acceleration, and displacement and converting the vibration signal. Each signal emitted from the detector is sent to the data processor 306. The workpiece is rotated by driving means 307. A marker (for example, a reflection sticker) 308 and a rotation detector (optical reflection sensor) 309 for detecting the rotation speed and rotation phase of the electrophotographic photosensitive drum are installed, and a signal is sent to the data processing device 306 to rotate the rotation speed and rotation. Calculate the phase. The vibration detector is installed on the bearings on both sides and measures the dynamic weight imbalance amount and the eccentric gravity center distance on both sides.

  Next, an example of a process for measuring the dynamic weight imbalance will be described with reference to FIG. The shaft portion of the workpiece 301 in which the engaging member is assembled to the electrophotographic photosensitive drum is received by the bearings 302 and 303 of the measuring device. The amplitude and phase of the initial vibration are measured with a detector while the workpiece is rotated at the same rotational speed as at the time of shaft processing, which is a subsequent process. The rotation is temporarily stopped, and a test weight 310 whose weight has been measured in advance is attached to the workpiece. The trial weight is a weight that is temporarily added to obtain the dynamic weight unbalance amount and the direction of unbalance. The vibration amplitude and phase are measured with a detector while rotating at the same rotational speed as when the shaft portion is processed again, and the dynamic weight imbalance amount and the direction of unbalance are obtained from the vibration amplitude and phase after addition of the initial and trial weights. Similar measurements are performed at different ends. In this way, the unbalanced load (the mass of the weight necessary for balancing) and its direction can be determined. Further, the dynamic eccentric gravity center distance E can be calculated from the dynamic weight imbalance amount and the mass of the electrophotographic photosensitive drum unit.

  Furthermore, it is possible to determine the direction, position, and size of the mass necessary for correcting the rotational balance based on the measurement results. As a result of the measurement, a weight balance is achieved by adding a weight of a specified mass in the indicated direction or by cutting the workpiece to reduce the mass. In some cases, the amplitude and phase of vibration are measured with a detector while rotating again at the same rotational speed as when processing the shaft portion, the weight balance is improved, and it is confirmed that the dynamic eccentric gravity center distance E is within a predetermined standard. A process may be added.

As a method of measuring and correcting the rotational weight imbalance amount of the rotating body so that the dynamic eccentric gravity center distance in the shaft portion is within 25 μm,
(1) Design and assemble so that the weight and position of each member constituting the electrophotographic photosensitive drum combined with the engaging member can be balanced;
(2) Measure rotational weight imbalance and correct rotational weight balance based on the result.
There is a way. As an example, the electrophotographic photosensitive drum and the engaging member are each designed to have a rotational weight balance, and are designed from the beginning so that the rotational weight balance of each position with the rotational center being axisymmetric can be achieved. . Examples of the method for correcting the balance in the above (2) include a method of adding a balance weight, for example, a method of attaching a weight to an electrophotographic photosensitive drum or a flange, or adding a weight screw. Further, there is a method in which a part of the electrophotographic photosensitive drum or flange that is a workpiece is cut to reduce the mass.

  In addition, a general electrophotographic photosensitive drum unit includes an electrophotographic photosensitive drum, an engaging member, and a conductive means (such as an earth pin and an earth spring) for establishing electrical connection between the electrophotographic photosensitive drum and the main body. Depending on the configuration of the electrophotographic apparatus, it may be necessary to add more parts to the electrophotographic photosensitive drum unit. For example, it may be necessary to increase the surface temperature of the electrophotographic photosensitive drum in order to prevent image flow, and when it is necessary to make the temperature of the electrophotographic photosensitive drum uniform, FIG. There is an example in which a planar heater 401 as shown in FIG. 1 is inserted into an electrophotographic photosensitive drum so as to be in close contact with the inner surface. In this case, in addition to the planar heater, the engaging member includes electrodes 402 and 403 for supplying power from the main body to the planar heater, and conductors 404 and 405 (covered copper wires) that connect the electrode and the planar heater. is necessary. A rotating weight balance including the heater and its related parts is required. Thus, in the electrophotographic photosensitive drum unit in which components are inserted into the electrophotographic photosensitive drum, the present invention is particularly effective because the balance is easily lost. There is also known an example in which a notch 406 is formed in a sheet heater so as to be in close contact with the entire inner surface of the electrophotographic photosensitive drum for easy balancing.

  In the electrophotographic photosensitive drum unit manufacturing method of the present invention, the step of processing the shaft portion of the engaging member into a similar circular shape around the center axis of the electrophotographic photosensitive drum outer circumference reference is performed at the same time as the other end engaging member. Processing to match the dimensional accuracy such as the length, diameter, chamfer, depth, roundness, straightness, and cylindricity, surface roughness, etc. of the outer periphery, inner periphery, and end of the shaft unit to the specified specifications. The dynamic eccentric gravity center distance in the shaft portion at that time is set to 25 μm or less, so that the rotation shaft is less shaken, biased and vibrated, and the processing accuracy is increased.

  The electrophotographic photosensitive drum unit according to the present invention is processed into a similar circular shape having the same central axis as the central axis of the outer periphery of the electrophotographic photosensitive drum, and is then electrophotographic photosensitive with respect to the central axis of the engaging member. The cylindrical drum swing accuracy of the body drum unit is preferably 50 μm or less. In particular, in an electrophotographic photosensitive drum unit that requires high accuracy, it is particularly preferable that the cylindrical swing accuracy is 30 μm or less.

  In the present invention, the cylindrical swing accuracy is measured as follows. The electrophotographic photosensitive drum unit is fixed with shafts or bearings that fit into the left and right shafts, and a laser shake measuring machine (measures the distance between the reference gauge with a straightness of 3 μm or less and the outer periphery of the electrophotographic photosensitive drum with a resolution of 1 μm. Measuring the displacement of the surface of the electrophotographic photosensitive drum unit image area at 10 points in the electrophotographic photosensitive drum unit bus line direction and circumferential direction by a laser length measuring machine (for example, manufactured by Shinko Co., Ltd.) The accuracy is measured by calculating the turning accuracy.

  The coaxiality is determined by measuring the outer periphery of the electrophotographic photosensitive drum of the electrophotographic photosensitive drum unit with a roundness meter to obtain the axis of the electrophotographic photosensitive drum, and the electrophotographic photosensitive drum unit is centered on the outer periphery of the electrophotographic photosensitive drum. Is rotated to measure the center of the electrophotographic photosensitive drum and the shaft portion with a roundness meter to obtain the axis, and the calculation is performed based on the axis.

  In the present invention, the dimensional accuracy of the shaft portion needs to be processed with high accuracy so as not to cause backlash when incorporated in an electrophotographic apparatus. In the present invention, the cylindrical substrate used in the electrophotographic photosensitive drum unit is not required to have high roundness and cylindricity of the inner diameter as long as the roundness and cylindricity of the outer periphery are finished with high accuracy. The photoconductor drum unit can be manufactured by a low cost method.

  Examples of the method of manufacturing a cylindrical substrate used in the present invention include a method of manufacturing a bottomed cylinder (DI method) by processing into a cup by deep drawing and then stretching the wall of the cup by ironing (impact extrusion). A method of manufacturing a cup cylinder by processing, then extending the wall of the cup by ironing and manufacturing a bottomed cylinder (Method II), a method of extending a cylinder obtained by extrusion processing by ironing and manufacturing a thin cylinder ( EI method), a method of producing a thin-walled cylinder by further drawing after extrusion (ED method), and the like. Moreover, the example of the cylindrical member manufactured by raising the precision of the hollow pipe extruded by the porthole system by the drawing process of 1 step | paragraph or 2 steps | paragraphs or more is also mentioned. An example in which the above cylindrical member is cut and both end portions are subjected to deburring processing and end taper processing as required is also included.

  The cylindrical base body used in the present invention may be used by processing the end portion after obtaining a cylinder having improved accuracy by drawing after extrusion of the aluminum alloy. In order to further increase the roundness and cylindricity of the outer periphery of the cylindrical substrate obtained by the above method, a method of cutting and grinding the outer periphery as necessary may be performed. In particular, as a means for obtaining a cylindrical substrate having a high roundness or cylindricity on the outer periphery, cutting, particularly lathe processing is preferable.

  In the present invention, examples of the material of the cylindrical substrate include metals such as aluminum, copper, iron, nickel, titanium, and alloys thereof, and plastics, ceramics, glass, and the like that have been subjected to conductive treatment. Preferably, JIS 3000 (Al—Mn), JIS 5000 (Al—Mg), or JIS 6000 (Al—Mg—Si) aluminum or aluminum alloy is used.

  The engaging member used in the present invention has a lower level of accuracy than that used in the conventional method of manufacturing a high-precision electrophotographic photosensitive drum unit when the method of manufacturing the electrophotographic photosensitive drum unit of the present invention is used. Even if it is used, a highly accurate electrophotographic photosensitive drum unit can be obtained by applying the manufacturing method of the electrophotographic photosensitive drum unit of the present invention. In other words, if the roundness and dimensional accuracy of the outer periphery of the joint are finished to predetermined accuracy, the roundness of the shaft is not important, and a high-precision electrophotographic photosensitive drum unit can be obtained at a level obtained by normal molding. It is possible to manufacture.

  An example of the shape of the engaging member in the electrophotographic photosensitive drum unit of the present invention will be described with reference to FIG. The engaging member has a shaft portion 107, and has a cylindrical coupling portion 407 through which the electrophotographic photosensitive drum unit is supported at a predetermined position in the electrophotographic apparatus. Insert the drum inside and fix the engaging member. The cylindrical coupling portion needs to be rounded at the outer peripheral portion so as not to deform the electrophotographic photosensitive drum when inserted inside the electrophotographic photosensitive drum. Further, the engaging member includes a flange portion 408 that connects the shaft portion and the cylindrical coupling portion. The flange portion needs to have sufficient strength to rotate the electrophotographic photosensitive drum around the predetermined axis 108 with high accuracy. In order to perform centering processing of the shaft or the bearing portion while rotating around the center axis of the outer peripheral reference of the electrophotographic photosensitive member, sufficient strength is required so that vibration does not occur in the shaft portion during processing. . Therefore, an example in which reinforcing beams (ribs) are provided in the flange portion and the shaft portion in order to increase the strength can be given. Further, as an example of the shape having the surface heater, an example in which the engagement member has electrodes 402 and 403 for supplying electric power from the main body to the surface heater can be given.

  The joining accuracy of the electrophotographic photosensitive drum and the engaging member used in the present invention is lower than the standard of the conventional method for producing a high-precision electrophotographic photosensitive drum unit. By applying the manufacturing method, a highly accurate electrophotographic photosensitive drum unit can be obtained. Even with an accuracy level obtained by normal bonding and press-fitting, it is possible to manufacture a more accurate electrophotographic photosensitive drum unit.

  The cylindrical substrate used in the present invention may be subjected to known surface treatments as required, coating of an intermediate layer or a conductive layer for the purpose of preventing injection, preventing interference fringes, protecting surface defects, and the like.

  As the photosensitive layer of the electrophotographic photosensitive drum used in the present invention, an inorganic photosensitive member or an organic photosensitive member is used, but there is no particular limitation, and the layer structure may be a single layer type or a laminated structure type. Examples thereof include those having a protective layer on the photosensitive layer.

  The cylindrical swing accuracy of the electrophotographic photosensitive drum unit of the present invention is preferably 50 μm or less, more preferably 30 μm or less, in order to prevent multicolor image misalignment, image unevenness and the like in applications such as full-color printing. .

  The method of manufacturing the electrophotographic photosensitive drum unit of the present invention can be applied to other cylindrical members and members having a shaft portion used in the electrophotographic apparatus, such as a developing sleeve, a charging roller, a feeding roller, and a fixing roller. .

  Next, the present invention will be specifically described with reference to the following examples, but the present invention is not limited to these examples. In the examples, “part” indicates mass part, and the definition of the accuracy measurement tolerance in the examples is based on JIS-B0021 and JIS-B0621.

Example 1
A hollow pipe (made of aluminum alloy JIS-A3003) manufactured by extrusion and further drawing was cut to obtain a cylindrical member having an outer diameter of 60.4 mm, an inner diameter of 57.6 mm, and a length of 344 mm. Next, both ends were cut by cutting to adjust the overall length and the perpendicularity of the end face, and further chamfered with C0.3 (linearly 0.3 mm) on the inside and outside.

  Next, the outer peripheral surface of the cylindrical base was cut by a lathe processing device. The processing conditions were a cylindrical substrate rotation speed of 3000 rpm, a feed pitch per rotation of the cylindrical substrate of 0.12 mm / rev, and a cutting depth of 0 with a sintered diamond tool of R0.5 (0.5 mm in curve) first. .Rough cutting was performed at 2 mm. Further, finishing was performed with a diamond miracle bit with a cut depth of 0.03 mm. The obtained substrate had an outer diameter of 59.94 mm and a length of 340 mm. A surface roughness Rz = 0.15 μm (surface roughness meter: measured using a surface roughness meter Surfcorder SE3500, Kosaka Laboratory, with a cutoff of 0.8 mm and a measurement length of 8 mm) was obtained.

Next, the following photosensitive layer was formed on the substrate. SnO ₂ coating treatment 10 parts of barium sulfate, 3 parts of titanium oxide, 6 parts of phenol resin, 6 parts of methanol, and 20 parts of methoxypropanol are prepared. A conductive layer coating solution is prepared and applied to the obtained cylindrical member substrate. Then, thermosetting was performed at 140 ° C. for 30 minutes to form a conductive layer having a film thickness of 15 μm.

  Next, 8 parts of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) and 12 parts of methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Co., Ltd.) are mixed with 300 parts of methanol / 250 n-butanol. An intermediate layer having a film thickness of 0.5 μm was formed by applying a coating material dissolved in a part of the mixed solvent and drying with hot air at 95 ° C. for 13 minutes.

  Next, after dispersing a solution consisting of 7 parts of oxygallium phthalocyanine pigment, 4 parts of polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 70 parts of cyclohexanone in a sand mill using glass beads for 6 hours. Then, 100 parts of ethyl acetate was added to prepare a dispersion for the charge generation layer. This dispersion was applied onto the intermediate layer and dried by heating at 95 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.15 μm.

  Next, 8 parts of an amine compound represented by the following structural formula,

下記構造式で示されるアミン化合物３部、

3 parts of an amine compound represented by the following structural formula,

及びビスフェノールＺ型ポリカーボネート樹脂（商品名：ユーピロンＺ−２００、三菱ガス化学社製）１０部をモノクロロベンゼン８０部／ジメトキシメタン２０部の混合溶媒に溶解した。この塗料を電荷発生層上に塗布し、１３０℃で１時間乾燥することによって、膜厚が１５μｍの電荷輸送層を形成した。

And 10 parts of bisphenol Z-type polycarbonate resin (trade name: Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Company) was dissolved in a mixed solvent of 80 parts monochlorobenzene / 20 parts dimethoxymethane. This paint was applied onto the charge generation layer and dried at 130 ° C. for 1 hour to form a charge transport layer having a thickness of 15 μm.

  The obtained electrophotographic photosensitive drum after application of the photosensitive layer had an outer diameter of 60.0 ± 0.02 mm, a length of 340.0 ± 0.2 mm, and a mass of 400 ± 30 g. Using a roundness meter (trade name: RA-662, manufactured by Mitutoyo Corporation), the roundness (maximum circumscribed circle and maximum inscribed circle) of the 5 mm portion from both ends of the outer peripheral surface of the obtained electrophotographic photosensitive drum The result of measuring the difference was within 15 μm. Furthermore, the result of measuring the outer diameter shape at 8 points every 5 mm from 5 mm from the end of one outer peripheral surface using a roundness meter and measuring the cylindricity was within 20 μm.

  Further, as a result of measuring the inner circumference accuracy using a roundness meter as the accuracy of the electrophotographic photosensitive drum, the inner diameter roundness of the 5 mm portion from the end portion is 30 μm or less, and the end portion measured using the roundness meter As a result of calculating the concentricity (distance between the center of the outer periphery and the center of the inner periphery) from the shape of the outer periphery and inner periphery of the 5 mm portion, it was 40 μm or less.

  Next, an engagement having a planar heater manufactured by molding, an electrode for supplying power to the planar heater, and a conductor (covered copper wire) connecting the electrode and the planar heater. A member (made of polycarbonate) was prepared.

The accuracy before processing the engaging member is as follows.
・ Cylindrical coupling part φ57.6 ± 0.05 mm (measured with a micrometer (manufactured by Mitutoyo Corporation))
・ Height of cylindrical coupling part 14mm (measured with calipers (manufactured by Mitutoyo Corporation))
・ Roundness of the outer periphery of the cylindrical joint is 15μm or less (measured 7mm from the end using a roundness meter)
・ Cylindricality of the outer peripheral part of the cylindrical coupling part is 20 μm or less (2mm, 7mm and 12mm parts are measured from the end using a roundness meter)
・ Outer diameter φ19.4 ± 0.2mm before shaft processing (measured with a micrometer (Mitutoyo Co., Ltd.))
・ Shaft length overhang from flange 21 ± 0.5mm (measured with vernier calipers (Mitutoyo Corporation))
・ Shaft outer circumference roundness within 60μm (Measure 15mm from shaft end using roundness meter)
・ Shaft outer circumference cylindricity within 60μm (Measure 5mm, 15mm, 25mm and 35mm from shaft end using roundness meter)
・ Concentricity of shaft and cylindrical joint is within 60μm (Measure 25mm from shaft end using roundness meter)

  Furthermore, a sheet heater with a heating element affixed to a polyester film is inserted so as to be in close contact with the entire inner surface of the electrophotographic photosensitive drum, and an electrode is further attached to the engagement member, and the electrode and the sheet heater are coupled with a coated copper wire. did. After the planar heater and the coated copper wire were assembled and inserted into the electrophotographic photosensitive drum, the engaging member was fixed with a cyanoacrylate adhesive (trade name: Aron α, manufactured by Toagosei Co., Ltd.). After the adhesive was sufficiently cured, the workpiece was placed in the measuring apparatus having the configuration shown in FIG. As the detector and the data processing device, a field balancer SB7300R for precision machinery, manufactured by Sigma Electronics Co., Ltd. was used. The amplitude and phase of the initial vibration were measured with a detector while the workpiece was rotated at the same rotation speed of 1000 rpm as in the later step of shaft processing. After temporarily stopping the rotation and attaching a test weight (5 g) that has been weighed in advance to the workpiece, measure the vibration amplitude and phase with the detector while rotating again at the same rotational speed as when processing the shaft part. From the vibration amplitude and phase after adding the trial weight, the dynamic weight unbalance amount and the unbalance direction at both ends (two sides) were obtained, and the unbalanced load (weight of the weight necessary for balancing) and its direction were determined. . Further, the dynamic weight imbalance amount was obtained from the mass of the work piece and the dynamic eccentric gravity center distance E was obtained and shown in Table 1. The weight balance was adjusted by adding a weight of a designated mass in the direction indicated as a result of the measurement (by inserting a screw into a hole previously drilled in the vicinity of the engaging member cylindrical coupling portion). Further, the amplitude and phase of vibration were measured with a detector while rotating again at the same rotational speed of 1000 rpm as in the shaft processing, and it was confirmed that the dynamic eccentric gravity center distance E was within 25 μm.

  The engaging member shaft portion was corrected to the following specifications with the processing apparatus shown in FIG. 2 and the hatched portion 501 was cut as shown in FIGS. 5 (A) and 5 (B). The support roller was brought into contact with a 5 mm portion from the end of the workpiece to the end of the surface, and the workpiece was rotated at 1000 rpm. In the processing apparatus of FIG. 5C, the cutting member 205 is movable in parallel with the rotation axis by the rail 503 attached to the tool table 502 and in the direction perpendicular to the rail 504. First, the cutting member 205 was first brought into contact with the end portion of the shaft portion, and the shaft portion length was processed to a predetermined dimension while being moved in a direction perpendicular to the rotation axis of the workpiece. Next, machining was performed so that the outer periphery of the shaft portion had a predetermined dimension while moving the cutting member 205 in contact with the outer periphery of the shaft portion and moving in a direction parallel to the rotation axis of the workpiece. The position of the processing member 205 of the processing apparatus was adjusted while measuring with a micrometer so that the outer diameter of the shaft portion was φ20.00 mm (tolerance within −0 / + 30 μm). Cutting member of processing device while measuring with calipers so that the length of the shaft portion protruding from the flange portion is 20 mm on both sides, and further the electrophotographic photosensitive drum unit overall length is 380.0 mm (tolerance is within 0 / + 0.1 m). The position of 205 was adjusted.

  As a result of measuring the accuracy of the manufactured electrophotographic photosensitive drum unit in the same manner as before processing, the outer diameter of the shaft portion after processing the engaging member was φ20.008 mm, and the length of one shaft portion protruding from the shaft portion flange portion was The length (hereinafter referred to as A side) was 20.05 mm, and the length of the other shaft portion (hereinafter referred to as B side) was 20.95 mm. Further, the total length of the electrophotographic photosensitive drum unit was 380.0 mm. Further, the roundness of the outer circumference of the shaft portion was 6 μm on the A side, 7 μm on the B side, the accuracy of the cylindricity of the shaft portion was 4 μm, and the coaxiality between the outer periphery of the shaft portion and the outer periphery of the electrophotographic photosensitive drum was 5 μm.

  The manufactured electrophotographic photosensitive drum unit is fixed with a bearing that fits to the outer diameter of the left and right shafts, and a laser shake measuring machine (the distance between the reference gauge with a straightness of 3 μm or less and the outer circumference of the electrophotographic photosensitive drum is resolved) Measure the displacement of the surface of the electrophotographic photosensitive drum unit with a laser length measuring machine (manufactured by Shinko Co., Ltd.) measuring at 1 μm in the electrophotographic photosensitive drum unit bus line direction and 10 points in the circumferential direction. Calculated accuracy).

  The electrophotographic photosensitive drum unit was manufactured through the above steps, and the outer peripheral surface deflection cylindrical swing accuracy of the 300 mm portion excluding the 20 mm portion from both ends of the electrophotographic photosensitive drum was measured. The results are shown in Table 1.

<Evaluation>
The electrophotographic photosensitive drum unit thus produced is mounted on a tandem color copier (product name: Color Laser Copier 5000, manufactured by Canon Inc.), and color evaluation and halftone image unevenness are output and image evaluation is performed. went. The results are shown in Table 1.

The halftone image is one in which one effective line and two white lines are alternately continued, and one scanned in the vertical direction and the horizontal direction was used. The evaluation criteria are as follows. The evaluation results are shown in Table 1.
(Color shift)
A: Good.
○: Image unevenness but good level as a product.
×: Defect, cannot be used as a product.
(Image unevenness)
A: Good.
○: Image unevenness but good level as a product.
×: Defect, cannot be used as a product.

  Regarding the cylindrical swinging accuracy of the electrophotographic photosensitive drum unit, it was judged that a value less than 30 μm was particularly good, a value of 30 μm to 50 μm was good as a product, and a value larger than 50 μm was bad. Regarding the outer diameter accuracy of the shaft portion, 0 μm or less −30 μm or more was judged good, larger than 0 μm, and smaller than −30 μm, it was judged as defective.

(Examples 2 to 5)
The same electrophotographic photosensitive drum, engaging member, and planar heater as in Example 1 were prepared, assembled, and joined. The rotational weight imbalance is measured by the same method as in Example 1, the balance is corrected, and the measurement results before and after the balance correction are shown in Table 1. Further, the shaft portion was processed in the same manner as in Example 1. Evaluation was conducted in the same manner as in Example 1, and the results are shown in Table 1. Further, 1000 images were output continuously in a high temperature and high humidity (35 ° C./85% RH) environment, but no image flow occurred and a good image was obtained.

(Example 6)
The same electrophotographic photosensitive drum, engaging member, and planar heater as in Example 1 were prepared, assembled, and joined. The rotational weight imbalance was measured and the balance was corrected by the same method as in Example 1 (balance correction was performed by cutting the flange portion with an end mill to correct the balance). Table 1 shows the measurement results before and after the balance correction. Further, the shaft portion was processed in the same manner as in Example 1. Evaluation was conducted in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Examples 1-2)
The same electrophotographic photosensitive drum, engaging member, and planar heater as in Example 1 were prepared and joined. The rotational weight imbalance is measured by the same method as in Example 1, the balance is corrected, and the measurement results before and after the balance correction are shown in Table 1. Further, the bearing portion was processed in the same manner as in Example 1. Evaluation was conducted in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Example 3)
The same electrophotographic photosensitive drum, engaging member, and planar heater as in Example 1 were prepared and joined. The rotational weight imbalance was measured in the same manner as in Example 1, but the balance was not corrected. Table 1 shows the measurement results before the balance correction. Evaluation was conducted in the same manner as in Example 1, and the results are shown in Table 1.

(Comparative Example 4)
In the same manner as in Example 1, a cylindrical member coated with a photosensitive layer, an engaging member, and a planar heater were prepared, assembled, and joined. Before assembling the shaft portion of the engaging member to the cylindrical member, the shaft portion of the engaging member was cut to an accuracy of an outer diameter φ19.970 mm and then joined in the same manner as in Example 1. As a result of evaluation in the same manner as in Example 1, the dimensional accuracy was good, but the cutting process was further increased, the cylindrical swing accuracy was not good, and color misregistration occurred as a result of image evaluation, and a good image was obtained. There wasn't.

(Example 7)
1000 cylindrical substrates with an excellent thickness balance within 30 μm were prepared, and a photosensitive layer was formed in the same manner as in Example 1. A flat heater is not inserted, and an engagement member that does not have an electrode for power supply is prepared. The engagement member is designed to minimize the mass deviation of the engagement member. Both sides were within 4 g. After assembling the electrophotographic photosensitive drum and the engaging member, the rotational weight imbalance measurement was performed in the same manner as in Example 1. As a result, the dynamic eccentric gravity center distance E of 1000 workpieces was 13 μm on average and 20 μm at the maximum. there were.

  Further, the bearing portion was processed in the same manner as in Example 1. As a result of evaluation in the same manner as in Example 1, the average cylindrical swing was 20 μm, and the maximum was 30 μm. As a result of the image evaluation, both image unevenness and color misregistration were good and the product was at a satisfactory level.

FIG. 2 is a diagram illustrating a configuration of an electrophotographic photosensitive drum unit according to the present invention. It is a figure explaining the method of processing the axial part of an engaging member, and performing centering. It is a schematic diagram of an apparatus for measuring the rotational weight balance of the electrophotographic photosensitive drum unit of the present invention. It is a schematic diagram of an engaging member and a sheet heater of the electrophotographic photosensitive drum unit of the present invention. It is a schematic diagram of shaft processing of the electrophotographic photosensitive drum unit of the present invention.

Explanation of symbols

101 Electrophotographic photosensitive drum unit (workpiece)
102 Electrophotographic photosensitive drum 103 Photosensitive layer 104, 105 Engaging member 106, 107 Shaft portion 108 Electrophotographic photosensitive drum unit rotating shaft 109 Eccentric engaging member shaft center 110 Developing means 201a, 201b Support rollers 202a, 202b Support roller 203a 203b Support roller 204 Cutting member 301 Workpiece 302, 303 Rotational weight balance measuring device bearing 304, 305 Vibration detector 306 Rotating weight balance measuring device data processing device 307 Rotating weight balance measuring device rotating means 308 Seal 309 Rotometer detector 310 Test Weight 401 Planar Heater 402, 403 Electrode 404, 405 Conductor (Coated Copper Wire)
406 Planar heater notch 407 Cylindrical coupling portion 408 Flange portion 501 Cutting portion 502 Tool table 503 Tool table rail X axis 504 Tool table rail Y axis

Claims (6)

  A method of manufacturing an electrophotographic photosensitive drum unit comprising at least an electrophotographic photosensitive drum and an engaging member having a shaft portion, wherein the engaging weight is coupled to the electrophotographic photosensitive drum, and then the rotational weight imbalance Measuring the amount and setting the dynamic eccentric gravity center distance in the combined shaft portion to be within 25 μm, and rotating the electrophotographic photosensitive drum combined with the engagement member to rotate the shaft portion of the engagement member And a step of processing the electrophotographic photosensitive drum unit into a similar circular shape around the center axis of the outer peripheral reference of the electrophotographic photosensitive drum.   An electrophotographic photosensitive drum in which the engagement member is coupled so that a dynamic eccentric gravity center distance in the coupled shaft portion is within 25 μm is measured after coupling the engagement member. 2. The method of manufacturing an electrophotographic photosensitive drum unit according to claim 1, wherein the weight and position of each member to be designed are designed and assembled.   The step of measuring the rotational imbalance after coupling the engaging members and setting the dynamic eccentric gravity center distance in the coupled shaft portions to be within 25 μm is a step of correcting the rotational balance based on the result of the rotational balance measurement. The method for producing an electrophotographic photosensitive drum unit according to claim 1.   The step of measuring the rotational weight imbalance after coupling the engaging members and setting the dynamic eccentric gravity center distance in the coupled shaft portions to be within 25 μm is a step of adding or cutting a balance weight. A method for producing the electrophotographic photosensitive drum unit according to the description.   5. A process cartridge comprising an electrophotographic photosensitive drum unit manufactured by the method for manufacturing an electrophotographic photosensitive drum unit according to claim 1, and detachable from an electrophotographic apparatus main body.   An electrophotographic apparatus having an electrophotographic photosensitive drum unit, a charging unit, an exposing unit, a developing unit, and a transferring unit, wherein the electrophotographic photosensitive drum unit is the electrophotographic photosensitive drum unit according to claim 1. An electrophotographic apparatus manufactured by a manufacturing method.

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