JP5818521B2 - Electrophotographic equipment - Google Patents

Description

  The present invention relates to an electrophotographic apparatus.

  An electrophotographic apparatus having an electrophotographic photosensitive member is widely used as, for example, a copying machine, a facsimile, and a printer.

  FIG. 2 is a diagram illustrating an example of the configuration of the electrophotographic apparatus. Hereinafter, an image forming process (electrophotographic process) by the electrophotographic apparatus will be described with reference to FIG.

  A cylindrical electrophotographic photosensitive member 2001 is rotated by a rotation drive mechanism (not shown). The surface of the rotating electrophotographic photosensitive member 2001 is charged by a charging device having a charging roller 2002 disposed in contact with the surface (outer peripheral surface) of the electrophotographic photosensitive member 2001. Thereafter, an image exposure apparatus (not shown) irradiates the surface of the electrophotographic photosensitive member 2001 with image exposure light 2003 to form an electrostatic latent image on the surface of the electrophotographic photosensitive member 2001. Thereafter, the electrostatic latent image formed on the surface of the electrophotographic photosensitive member 2001 is developed with toner in the developing device 2004 to form a toner image on the surface of the electrophotographic photosensitive member 2001.

  This toner image is transferred from the surface of the electrophotographic photosensitive member 2001 to the transfer material 2006 by the transfer device 2005. Thereafter, the transfer material 2006 is separated from the surface of the electrophotographic photoreceptor 2001, and the toner image is fixed to the transfer material 2006 by a fixing device (not shown).

  Even after the toner image is transferred to the transfer material 2006, the toner remaining on the surface of the electrophotographic photosensitive member 2001 (transfer residual toner) has a cleaning blade 2009 disposed in contact with the surface of the electrophotographic photosensitive member 2001. Removed by device 2007. Prior to the removal of the transfer residual toner by the cleaning blade 2009, the transfer residual toner is rubbed by a magnet roller 2008 having a magnetic brush as necessary.

  Thereafter, if necessary, the surface of the electrophotographic photoreceptor 2001 is discharged by irradiating the surface of the electrophotographic photoreceptor 2001 with pre-exposure light by the pre-exposure device 2010.

  Image formation is continuously performed by repeating the above process.

  Such an electrophotographic apparatus is required to maintain high image quality even when used repeatedly for a long time.

  However, when the electrophotographic photosensitive member is repeatedly used for a long period of time, the surface of the electrophotographic photosensitive member is scraped by a mechanical load due to contact with the charging roller or the cleaning blade.

  Further, if the surface of the electrophotographic photosensitive member is shaken by the rotation (hereinafter referred to as “rotational shake”), the contact with the charging roller and the cleaning blade becomes uneven, and the surface of the electrophotographic photosensitive member is scraped. Unevenness (hereinafter referred to as “scraping unevenness”) tends to occur. When shaving unevenness occurs, unevenness occurs in the amount of light transmitted through the surface of the electrophotographic photosensitive member, resulting in non-uniformity in sensitivity of the electrophotographic photosensitive member (hereinafter referred to as “sensitivity unevenness”). When uneven sensitivity occurs, unevenness of the surface potential of the electrophotographic photosensitive member during image formation is caused, resulting in uneven density in the output image (hereinafter referred to as “image density unevenness”), and maintaining high image quality. Disappear.

  Patent Documents 1 and 2 disclose a technique in which a vibration isolating material and a sound deadening material are placed inside the electrophotographic photosensitive member in order to remove vibration and noise caused by the rotation of the electrophotographic photosensitive member.

JP 2001-013704 A JP 2001-235971 A

  An object of the present invention is to provide an electrophotographic apparatus in which the rotational shake of the electrophotographic photosensitive member is suppressed.

  As a result of intensive studies to suppress the rotational shake of the electrophotographic photosensitive member, the present inventors have determined that the rotational shake of the electrophotographic photosensitive member causes the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit to be It has been found that it can be suppressed by being positioned on the rotational drive mechanism side from the center in the longitudinal direction.

That is, the present invention
A cylindrical electrophotographic photosensitive member, and an electrophotographic photosensitive member unit having a first bearing and a second bearing for rotatably supporting both ends of the electrophotographic photosensitive member in the electrophotographic apparatus;
A rotation drive mechanism having an output gear for outputting a rotation drive force for rotating the electrophotographic photosensitive member in the electrophotographic apparatus;
A charging device having a charging roller disposed in contact with the surface of the electrophotographic photosensitive member;
An image exposure apparatus;
A developing device;
A transfer device;
An electrophotographic apparatus having a cleaning device having a cleaning blade disposed in contact with the surface of the electrophotographic photosensitive member,
The electrophotographic photosensitive unit further has an input gear that can mesh with the output gear,
The electrophotographic photosensitive member has a cylindrical base, a photoconductive layer made of amorphous silicon on the base, and a first flange and a second flange fitted to both ends of the base. ,
The first bearing is attached to the first flange, and the second bearing is attached to the second flange;
The input gear is not attached to the first flange, the input gear is attached only to the second flange,
The longitudinal length of the electrophotographic photosensitive member unit is A, and the distance from the longitudinal center of the electrophotographic photosensitive member unit to a longitudinal center of gravity of the electrophotographic photosensitive member unit was B, 0. The electrophotographic apparatus satisfies the relationship of 04 ≦ B / A ≦ 0.13 .

  According to the present invention, it is possible to provide an electrophotographic apparatus in which the rotational shake of the electrophotographic photosensitive member is suppressed.

FIG. 2 is a diagram (schematic cross-sectional view) illustrating an example of a configuration of an electrophotographic photoreceptor unit. 1 is a diagram (schematic cross-sectional view) illustrating an example of a configuration of an electrophotographic apparatus. 1 is a diagram (schematic cross-sectional view) illustrating an example of a layer configuration of an electrophotographic photosensitive member. 1 is a diagram (schematic cross-sectional view) illustrating an example of a configuration of a deposited film forming apparatus using an RF plasma CVD method for producing an electrophotographic photosensitive member. It is a figure for demonstrating the measuring method of an electrophotographic photoreceptor unit and a gravity center. FIG. 2 is a diagram (schematic cross-sectional view) illustrating an example of a configuration of an electrophotographic photoreceptor unit.

  FIG. 1 is a diagram showing an example of the configuration of the electrophotographic photosensitive member unit.

  The electrophotographic photosensitive member unit 1000 mainly includes a cylindrical electrophotographic photosensitive member 1001, a first bearing 10061 and a second bearing for rotatably supporting both ends of the electrophotographic photosensitive member 1001 in the electrophotographic apparatus. 10062. Here, “bearing” is synonymous with “bearing”. The electrophotographic photoreceptor 1001 has a first flange 1002 and a second flange 1003 that are fitted to both ends of a cylindrical base (not shown). In the example of FIG. 1, the first flange 1002 and the second flange 1003 have shaft portions 10021 and 10031 that protrude outward in the longitudinal direction of the base body (not shown). The first bearing 10061 is attached to the first flange 1002 (the shaft portion 10021), and the second bearing 10062 is attached to the second flange 1003 (the shaft portion 10031). Further, the electrophotographic photoreceptor unit 1000 has a stay 1005, a weight 1012 attached to the stay 1005, and screws 10041 to 10044 for connecting the first flange 1002 and the second flange 1003 to the stay 1005. doing. The inner surfaces of both ends of the electrophotographic photoreceptor 1001 are subjected to inlay processing to form inlay processed portions 10081 and 10082. The first flange 1002 and the second flange 1003 are fitted into the inlay processed portions 10081 and 10008, respectively, and are fastened to the stay 1005 by screws 10041 to 10044, and are fixed so as to sandwich the electrophotographic photoreceptor 1001. .

  In FIG. 1, A is the length in the longitudinal direction of the electrophotographic photosensitive member unit 1000, and is the distance from the center of the first bearing 10061 to the center of the second bearing 10062. A position obtained by dividing the line connecting the center of the first bearing 10061 and the center of the second bearing 10062 into two equals is a center 1011 in the longitudinal direction of the electrophotographic photosensitive member unit 1000. In Examples and Comparative Examples described later, a rolling bearing (ball bearing) is used as a bearing, but a bearing (for example, a sliding bearing) other than the rolling bearing (ball bearing) may be used. In that case, the position in the longitudinal direction of the electrophotographic photosensitive member unit is a position that bisects the line connecting the centers of the portions where the slide bearings installed at both ends of the electrophotographic photosensitive member unit and the shaft contact each other. . Thus, the longitudinal center of the electrophotographic photosensitive member unit is a position that bisects a line connecting the centers of the first bearing and the second bearing.

  In FIG. 1, reference numeral 1010 denotes the center of gravity of the electrophotographic photoreceptor unit 1000 in the longitudinal direction. B is the distance from the center 1011 of the electrophotographic photoreceptor unit 1000 to the center of gravity 1010 in the longitudinal direction of the electrophotographic photoreceptor unit 1000.

  In FIG. 1, the input gear 1007 is attached only to the second flange 1003 (the shaft portion 10031). The input gear 1007 is a gear that can mesh with an output gear 1009 for outputting a rotational driving force for rotating the electrophotographic photosensitive member 1001 in the electrophotographic apparatus. A rotational driving force for rotating the electrophotographic photosensitive member 1001 in the electrophotographic apparatus is transmitted from the rotational driving mechanism (not shown) to the electrophotographic photosensitive member 1001 through the output gear 1009 and the input gear 1007. The input gear 1007 is not attached to the first flange 1002. That is, the electrophotographic photosensitive member unit 1000 is connected to the output gear 1009 of the rotation drive mechanism (not shown) via the input gear 1007 only in one of the longitudinal directions. The reason why the electrophotographic photosensitive member unit is connected to the output gear of the rotational drive mechanism only in one of the longitudinal directions is that it is easy to remove the electrophotographic photosensitive member unit from the electrophotographic apparatus during maintenance. It is common to adopt a simple configuration.

  In the present invention, the longitudinal center of gravity 1010 of the electrophotographic photosensitive member unit 1000 is located closer to the second bearing 10062 than the center 1011 of the electrophotographic photosensitive member unit 1000.

  The reason why the rotational shake of the electrophotographic photosensitive member unit can be suppressed by using the above configuration will be described below.

  As described above, in general, the electrophotographic photosensitive member unit is connected to the rotation driving mechanism for rotating the electrophotographic photosensitive member in only one of the longitudinal directions, and the other in the longitudinal direction (the opposite side of the rotational driving mechanism). Is supported but not connected to the rotational drive mechanism. In such a configuration, the opposite side (first bearing side) of the rotation drive mechanism of the electrophotographic photosensitive member unit has a structure that is weaker against external force than the rotation drive mechanism side (second bearing side). ing. Therefore, when the electrophotographic photosensitive member (electrophotographic photosensitive member unit) is rotated, the opposite side of the rotational driving mechanism is axially centered by the rotational driving force applied from the rotational driving mechanism to the electrophotographic photosensitive member (electrophotographic photosensitive member unit). Deviation becomes larger and rotational runout becomes larger.

  Here, if the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit is offset from the center in the longitudinal direction of the electrophotographic photosensitive member unit toward the second bearing side, that is, the rotational drive mechanism side, The load of the photoconductor unit is biased toward the rotational drive mechanism having a structure strong against external force. Therefore, the moment on the opposite side of the rotational drive mechanism is relatively reduced, and the rotational deviation of the electrophotographic photosensitive member is reduced by reducing the deviation of the axial center when the electrophotographic photosensitive member is rotated in the electrophotographic apparatus. It is suppressed.

  From the viewpoint of suppressing the rotational shake of the electrophotographic photosensitive member, the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit is the second bearing side from the longitudinal center of the electrophotographic photosensitive member unit, that is, the rotational drive mechanism side. The better it is. However, as the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit is biased toward the rotation drive mechanism, more weight is required to adjust the position of the center of gravity, and the load on the rotation drive mechanism tends to increase. is there. Therefore, the length A in the longitudinal direction of the electrophotographic photosensitive member unit defined as described above and the distance B from the center in the longitudinal direction of the electrophotographic photosensitive member unit to the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit are , 0.04 ≦ B / A ≦ 0.13 is preferably satisfied.

  As a method for measuring the position of the center of gravity of the electrophotographic photosensitive member unit in the longitudinal direction, for example, as shown in FIG. 5, the electrophotographic photosensitive member unit 1000 has a first bearing 10061 and a second bearing 10062, respectively. It is possible to employ a method of installing weight measuring instruments 10131 and 10132 and measuring the respective weights. In other words, the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit 1000 can be obtained from the ratio of the weights.

  As a method of adjusting the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit, in addition to the method of attaching the weight 1012 to the above-described stay 1005, the depth of the inlay processed portion formed on the inner surfaces of both ends of the electrophotographic photosensitive member 1001. There is a method of changing at both ends.

  The smaller the rotational speed of the electrophotographic photosensitive member (electrophotographic photosensitive member unit) in the electrophotographic apparatus, the more the effect of the present invention can be obtained.

  As for the method of supporting the cleaning blade in the cleaning device, the effect of the present invention can be remarkably obtained when a support method that does not have the function of causing the cleaning blade to follow the rotational shake of the electrophotographic photosensitive member is employed. This is because if the cleaning blade does not have a function to follow the rotational shake of the electrophotographic photosensitive member, and if the rotational shake of the electrophotographic photosensitive member occurs, the contact pressure (contact pressure) of the cleaning blade against the surface of the electrophotographic photosensitive member. ) Are likely to fluctuate, and the electrophotographic photosensitive member is more likely to be shaved.

  As for the electrophotographic photoreceptor, an electrophotographic photoreceptor having a photoconductive layer composed of amorphous silicon (hereinafter referred to as “a-Si”) (hereinafter referred to as “a-Si photoreceptor”). The effect of the present invention is remarkably obtained when using. This is because the a-Si photoconductor is very stable among various electrophotographic photoconductors, and therefore, surface shaving unevenness is often the largest cause of sensitivity unevenness and image density unevenness. It is from. Further, the effect of the present invention is remarkably obtained when the surface of the electrophotographic photosensitive member is easily scraped.

  FIG. 3 is a diagram (schematic cross-sectional view) showing an example of the layer structure of the electrophotographic photosensitive member. In the electrophotographic photosensitive member having the layer structure shown in FIG. 3, a charge injection blocking layer 3002 is provided on a cylindrical substrate 3001 for the purpose of blocking the injection of charges from the substrate 3001 to the photoconductive layer 3003. The photoconductive layer 3003 and the surface layer 3004 are sequentially provided thereon.

  The substrate is preferably a conductive substrate (conductive substrate), and the materials thereof include metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, Fe, and the like. An alloy (for example, an aluminum alloy, stainless steel, etc.) etc. are mentioned. Among these, an aluminum alloy is preferable from the viewpoint of workability and manufacturing cost, and specifically, an Al—Mg alloy and an Al—Mn alloy are preferable.

  Examples of the material for the surface layer include materials containing at least one of carbon atoms, nitrogen atoms and oxygen atoms and silicon atoms, such as amorphous silicon carbide, amorphous silicon nitride, and amorphous silicon oxide.

  FIG. 4 is a diagram (schematic cross-sectional view) showing an example of the configuration of a deposited film forming apparatus using an RF plasma CVD method for producing an electrophotographic photoreceptor (a-Si photoreceptor).

  The deposited film forming apparatus shown in FIG. 4 is roughly composed of a deposition apparatus 4100 having a reaction vessel 4110, a source gas supply device 4200, and an exhaust device (not shown) for reducing the pressure in the reaction vessel 4110. Yes.

  In the reaction vessel 4110 in the deposition apparatus 4100, a substrate 4112 connected to the ground, a substrate heating heater 4113, and a source gas introduction pipe 4114 are installed. Further, a high frequency power source 4120 is connected to the cathode electrode 4111 via a high frequency matching box 4115.

The source gas supply device 4200 mainly includes cylinders 4221 to 4225, valves 4231 to 4235, pressure regulators 4261 to 4265, inflow valves 4241 to SiH ₄ , H ₂ , CH ₄ , NO, B ₂ H _{6 and the} like. 4245, outflow valves 4251 to 4255, and mass flow controllers 4211 to 4215. The cylinder filled with each source gas is connected to a source gas introduction pipe 4114 in the reaction vessel 4110 via an auxiliary valve 4260. Reference numeral 4116 denotes a gas pipe.

  Next, a method for forming a deposited film using this deposited film forming apparatus will be described.

  First, the substrate 4112 that has been degreased and washed in advance is placed in the reaction container 4110 via a cradle 4123. Next, an exhaust device (not shown) is operated to exhaust the reaction vessel 4110. While viewing the display of the vacuum gauge 4119, when the pressure in the reaction vessel 4110 reaches a predetermined pressure (for example, 1 Pa or less), electric power is supplied to the substrate heating heater 4113, and the substrate 4112 is heated to a predetermined temperature (for example, 50 to 50). 350 ° C). At this time, an inert gas such as Ar or He can be supplied from the gas supply device 4200 to the reaction vessel 4110 and heated in an inert gas atmosphere.

  Next, the source gas used for forming the deposited film is supplied from the gas supply device 4200 to the reaction vessel 4110. That is, as necessary, the valves 4231 to 4235, the inflow valves 4241 to 4245, and the outflow valves 4251 to 4255 are opened, and the flow rate is set to the mass flow controllers 4211 to 4215. When the flow rate of each mass flow controller is stabilized, the main valve 4118 is operated while viewing the display of the vacuum gauge 4119 to adjust the pressure in the reaction vessel 4110 to a predetermined pressure. When a predetermined pressure is obtained, high frequency power is applied from the high frequency power source 4120 and the high frequency matching box 4115 is operated to generate plasma discharge in the reaction vessel 4110. Thereafter, the high-frequency power is quickly adjusted to a predetermined power to form a deposited film. Reference numeral 4121 denotes an insulating material.

  When the formation of the predetermined deposited film is finished, the application of the high-frequency power is stopped, the valves 4231 to 4235, the inflow valves 4241 to 4245, the outflow valves 4251 to 4255, and the auxiliary valve 4260 are closed, and the supply of the raw material gas is finished. . At the same time, the main valve 4118 is fully opened, and the reaction vessel 4110 is exhausted to a predetermined pressure (for example, 1 Pa or less).

  The formation of the deposited films is completed as described above. When a plurality of deposited films are formed, the above procedure may be repeated to form each deposited film. The junction region between the deposited films can also be formed by changing the flow rate or pressure of the source gas over a certain period of time.

  After all the deposited films are formed, the main valve 4118 is closed, the leak valve 4117 is opened, an inert gas is introduced into the reaction vessel 4110, and the pressure is returned to atmospheric pressure, and then a deposited film is formed on the surface. The substrate 4112 is taken out.

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited at all by these. In Example 1, the B / A value of 0.03 is a reference example.

Example 1
As a material for a conductive cylindrical substrate (hereinafter also simply referred to as “substrate”) for an electrophotographic photosensitive member, an aluminum tube having an inner diameter of 74 mm and a length of 358 mm was used.

  An inlay process having a depth of 13 mm and an inner diameter of 76 mm was applied to the inner peripheral surfaces of both ends of the tube material. The pipe material subjected to the inlay process was set on a lathe for outer peripheral surface machining, and the outer peripheral surface of the pipe material was cut using the inlay processed surface as a reference to obtain a pipe material having an outer diameter of 80 mm. This was used as a base for an electrophotographic photoreceptor.

  Four electrophotographic photosensitive members were produced using the above-mentioned substrate and the conditions shown in Table 1 using the deposited film forming apparatus shown in FIG.

  Each of the produced electrophotographic photosensitive members was sandwiched between two flanges (first flange and second flange), and four electrophotographic photosensitive member units having a configuration generally shown in FIG. 1 were produced. Then, as shown in Table 2, the positions of the weights attached to the stays for each of the four electrophotographic photoreceptor units are changed, and all are adjusted so that the position of the center of gravity in the longitudinal direction of the electrophotographic photoreceptor unit is closer to the rotational drive mechanism. did. The weight used was a 400 g weight. The mass of the electrophotographic photosensitive member unit with no weight attached is 1600 g. The position of the weight was 0 at the longitudinal center of the electrophotographic photosensitive member unit, + on the rotation drive mechanism side from the center, and-side on the opposite side of the rotation drive mechanism from the center.

(Comparative Example 1)
Two electrophotographic photoreceptor units were produced in the same manner as in Example 1. Then, as shown in Table 2, the positions of the weights attached to the stays with respect to the two electrophotographic photoreceptor units are changed, and the position of the center of gravity in the longitudinal direction of the electrophotographic photoreceptor unit is the center in the longitudinal direction of the electrophotographic photoreceptor unit. Or it adjusted so that it might be located in the other side of a rotation drive mechanism rather than a center.

(Evaluation of Example 1 and Comparative Example 1)
In order to evaluate rotational shake, shaving unevenness, and image density unevenness, a modified copy machine of Canon Inc. (trade name: iR5075) having a configuration shown in FIG. 2 was used as an electrophotographic apparatus for evaluation. . In this electrophotographic apparatus, the charging device is changed to one having a charging roller disposed in contact with the surface of the electrophotographic photosensitive member, the rotational speed by the rotational drive mechanism (rotational speed of the electrophotographic photosensitive member) is set to 80 rpm, and image exposure is performed. A laser light source having an oscillation wavelength of 635 nm is used as the apparatus, and the apparatus is modified so as to output an image with a resolution of 1200 dpi. In addition to these, the electrophotographic apparatus includes a developing device, a transfer device, and a cleaning device having a cleaning blade disposed in contact with the surface of the electrophotographic photosensitive member.

  The evaluation methods for rotational shake, shaving unevenness, and image density unevenness will be described below.

(Evaluation method for rotational runout)
The produced electrophotographic photosensitive member unit was installed in the electrophotographic apparatus. The installed electrophotographic photosensitive member unit was rotated at a speed of 80 rpm, and the magnitude of rotational shake was measured by a displacement sensor (KEYENCE: EX201, EX305). The measurement location was 9 points in the longitudinal direction of the electrophotographic photosensitive member (0 mm, ± 50 mm, ± 90 mm, ± 130 mm, ± 150 mm). Comparison was made with relative values when the value of rotational runout when B / A = 0 was assumed to be 100. As an evaluation result, it means that the smaller the number of the relative value is, the better, and it means that the effect of the present invention is obtained when the relative value is less than 100. Further, it was determined that the effect of the present invention was remarkably obtained when the relative value was 90 or less. The results are shown in Table 2.

(Evaluation method of shaving unevenness)
The film thickness of the surface layer of the electrophotographic photosensitive member immediately after production is 9 points in the longitudinal direction in any circumferential direction of the electrophotographic photosensitive member (0 mm, ± 50 mm, ± 90 mm, based on the center in the longitudinal direction of the electrophotographic photosensitive member, ± 130 mm, ± 150 mm), and rotated in 90 ° increments from the above-mentioned arbitrary circumferential direction, and measured at four points in the circumferential direction. That is, a total of 36 points of 9 points in the longitudinal direction × 4 points in the circumferential direction were measured.

  After measuring the film thickness of the surface layer, a continuous paper passing test was performed. Specifically, an electrophotographic photosensitive member unit is produced as described above, and 50,000 continuous sheet passing tests per day are performed using the electrophotographic apparatus using an A4 test pattern with a printing rate of 1%. It was carried out every day and up to 2 million copies. After the continuous paper passing test of 2 million sheets was completed, the electrophotographic photosensitive member unit was taken out from the electrophotographic apparatus. The film thickness of the surface layer of the electrophotographic photosensitive member of the taken-out electrophotographic photosensitive member unit was measured at the same measurement position as that immediately after the production in the same manner as immediately after the production. And the difference was calculated | required from the film thickness of the surface layer immediately after preparation and after a continuous paper passing test, and the amount of abrasion by the continuous paper passing test of 2 million sheets was calculated. Of the 36 measured points, the difference between the point with the largest amount of shaving and the point with the smallest amount of shaving was used as an index of shaving unevenness. A comparison was made with relative values when the value of shaving unevenness when B / A = 0 was assumed to be 100. As an evaluation result, it means that the smaller the number of the relative value is, the better, and it means that the effect of the present invention is obtained when the relative value is less than 100. Further, it was determined that the effect of the present invention was remarkably obtained when the relative value was 90 or less. The results are shown in Table 2.

  Hereinafter, a method for measuring the film thickness of the surface layer will be described in detail.

  First, a reference electrophotographic photosensitive member is formed by forming only a charge injection blocking layer and a photoconductive layer on a substrate (conductive cylindrical substrate), and the central portion in the longitudinal direction in any circumferential direction is 15 mm square. A reference sample was prepared by cutting out a square. Next, for an electrophotographic photosensitive member (electrophotographic photosensitive member whose thickness is to be measured) formed by forming a charge injection blocking layer, a photoconductive layer and a surface layer on a substrate, a 15 mm square is similarly cut out and measured. A sample was prepared.

  Next, the reference sample and the measurement sample were measured by spectroscopic ellipsometry (manufactured by JA Woollam: high-speed spectroscopic ellipsometry M-2000) to determine the refractive index of the surface layer.

  Specific measurement conditions of spectroscopic ellipsometry are incident angles: 60 °, 65 °, 70 °, measurement wavelengths: 195 nm to 700 nm, and beam diameter: 1 mm × 2 mm.

  First, regarding the reference sample, the relationship between the wavelength at each incident angle, the amplitude ratio Ψ, and the phase difference Δ was determined by spectroscopic ellipsometry.

  Next, using the result of the reference sample as a reference, the relationship between the wavelength at each incident angle, the amplitude ratio Ψ, and the phase difference Δ was also obtained for the measurement sample by spectroscopic ellipsometry as in the reference sample.

  Further, a layer structure in which a charge injection blocking layer, a photoconductive layer, and a surface layer are sequentially formed on a substrate and a roughness layer in which a surface layer and an air layer coexist is used as a calculation model. Then, the volume ratio between the surface layer of the roughness layer and the air layer was changed by analysis software, and the relationship between the wavelength at each incident angle, the amplitude ratio Ψ, and the phase difference Δ was obtained by calculation. The refractive index of the surface layer was calculated using this calculation model, and the obtained value was taken as the refractive index of the surface layer. As analysis software, J.H. A. Woolase WVASE32 was used. The volume ratio of the surface layer to the air layer of the roughness layer was calculated by changing the ratio of the air layer in the roughness layer by 1 from 10: 0 to 1: 9 in the surface layer: air layer. In the a-Si photoreceptor produced in Example 1, the relationship between the wavelength, the amplitude ratio Ψ, and the phase difference Δ obtained by calculation when the volume ratio of the surface layer to the air layer of the roughness layer is 8: 2. The mean square error of the relationship between the wavelength, the amplitude ratio Ψ and the phase difference Δ obtained by the measurement was minimized. This means that the accuracy of the calculated value is high when the volume ratio of the surface layer of the roughness layer to the air layer is 8: 2, and the refractive index was calculated using this volume ratio.

  Next, the surface of the electrophotographic photosensitive member is irradiated with light perpendicularly with a spot diameter of 2 mm, and the reflected light is spectroscopically measured using a spectrometer (trade name: MCPD-2000) manufactured by Otsuka Electronics Co., Ltd. It was. The film thickness of the surface layer was calculated based on the obtained reflection waveform. At this time, the wavelength range was 500 nm to 750 nm, the refractive index of the photoconductive layer was 3.30, and the refractive index of the surface layer was a value obtained from the above-described spectroscopic ellipsometry measurement.

(Evaluation method for uneven image density)
An electrophotographic photosensitive member (electrophotographic photosensitive member unit) after 2 million continuous sheet passing tests is installed in the electrophotographic apparatus, and three halftone images with an image ratio of 50% are output on A3 paper using the text mode. did. The image density at a position where the position where the film thickness of the surface layer was measured and the output image position coincided with each other when the shaving unevenness was evaluated was measured with a reflection densitometer (trade name: 504 spectral densitometer) manufactured by X-Rite Inc. The average value of image density was obtained at each measurement location. The difference between the highest image density value and the lowest image density was defined as image density unevenness. Comparison was made with relative values when the value of the image density unevenness when B / A = 0 was set to 100. As an evaluation result, it means that the smaller the number of the relative value is, the better, and it means that the effect of the present invention is obtained when the relative value is less than 100. Further, it was determined that the effect of the present invention was remarkably obtained when the relative value was 90 or less. The results are shown in Table 2.

  From Table 2, by positioning the position of the center of gravity of the electrophotographic photoreceptor unit in the longitudinal direction from the center in the longitudinal direction of the electrophotographic photoreceptor unit to the rotational drive mechanism side, the rotational shake, shaving unevenness of the electrophotographic photoreceptor unit, It can be seen that image density unevenness is suppressed. Moreover, it turns out that rotational shake is suppressed as B / A becomes large. B / A when the weight is attached so as to be closest to the rotational drive mechanism side is 0.08, which is the maximum value of B / A that can be taken in the first embodiment.

  Further, it can be seen from Table 2 that if the rotational shake is suppressed, shaving unevenness and image density unevenness are suppressed. Hereinafter, only the runout was evaluated.

(Example 2)
In the same manner as in Example 1, three electrophotographic photoreceptor units were produced. Then, the weights were fixed so that the weights attached to the electrophotographic photosensitive member unit were closest to the rotational drive mechanism side. Then, the weights of the respective weights were adjusted as shown in Table 3 to adjust the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit.

  Evaluation was performed in the same manner as in Example 1. The results are shown in Table 3.

  From Tables 2 and 3, it can be seen that even if the value of B / A is the same, the rotational shake is suppressed as the mass of the weight decreases. In Tables 2 and 3, since the rotational shake was most suppressed when B / A = 0.13 of Example 2, the influence of the B / A value was more than the influence of the weight mass. You can see that it is bigger.

(Example 3)
Six electrophotographic photoreceptor units were produced in the same manner as in Example 1. Then, the weights were fixed so that the weights attached to the electrophotographic photosensitive member unit were closest to the rotational drive mechanism side. Then, the weights of the respective weights were adjusted as shown in Table 4 to adjust the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit.

  Evaluation was performed in the same manner as in Example 1. At that time, the rotational speed of the electrophotographic photosensitive member unit was set as shown in Table 4, respectively. The results are shown in Table 4.

  From Table 4, it can be seen that as the rotational speed of the electrophotographic photosensitive member (electrophotographic photosensitive member unit) in the electrophotographic apparatus decreases, rotational shake is suppressed.

Example 4
An aluminum tube with an inner diameter of 27.6 mm, an outer diameter of 30 mm, and a length of 370 mm is used as the material of the substrate (conductive cylindrical substrate), and the inner peripheral surfaces of both ends of the tube material are not subjected to inlay processing. Except that, six electrophotographic photosensitive members were produced in the same manner as in Example 1.

  Using each of the produced electrophotographic photosensitive members, six electrophotographic photosensitive member units having a configuration generally shown in FIG. 6 were produced. Specifically, the electrophotographic photosensitive member 6001 was sandwiched between the first flange 6002 and the second flange 6003 to produce an electrophotographic photosensitive member unit 6000. A first bearing 60041 is attached to the first flange 6002 (shaft portion 60021), a second bearing 60042 is attached to the second flange 6003 (shaft portion 60031), and the second bearing 60042 is attached to the second bearing 60042. Attached an input gear 6005. The input gear 6005 is a gear that can mesh with an output gear 6010 for outputting a rotational driving force for rotating the electrophotographic photosensitive member 6001 in the electrophotographic apparatus. A rotational driving force for rotating the electrophotographic photosensitive member 6001 in the electrophotographic apparatus is transmitted to the electrophotographic photosensitive member 6001 from the rotational driving mechanism (not shown) via the output gear 6010 and the input gear 6005. The stay is not attached to the electrophotographic photosensitive member unit 6000. A plate-like weight 6006 was attached to the second flange 6003 using screws 60071 and 60072. The center 6009 in the longitudinal direction of the electrophotographic photoreceptor unit 6000 and the center of gravity 6008 in the longitudinal direction of the electrophotographic photoreceptor unit 6000 were obtained in the same manner as in Example 1 (FIG. 1). The weight of the electrophotographic photosensitive member unit without a weight is 130 g.

  The weight of each weight was adjusted as shown in Table 5, and the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit was adjusted.

  Evaluation was performed in the same manner as in Example 1 except that the electrophotographic apparatus for evaluation was changed to a modified machine of a copying machine (trade name: GP405) manufactured by Canon Inc. having a configuration shown in FIG. At that time, the rotational speed of the electrophotographic photosensitive member unit was set as shown in Table 5, respectively. The results are shown in Table 5.

(Example 5)
An aluminum tube having an inner diameter of 98 mm, an outer diameter of 108 mm, and a length of 358 mm is used as the material of the substrate (conductive cylindrical substrate). Except that, six electrophotographic photoreceptors were produced in the same manner as in Example 1, and six electrophotographic photoreceptor units were produced using them. The weight of the electrophotographic photosensitive member unit without a weight is 3900 g.

  The position of the weight attached to the electrophotographic photosensitive member unit was fixed at the position closest to the rotational drive mechanism side. The weights of the respective weights were adjusted as shown in Table 6 to adjust the position of the center of gravity in the longitudinal direction of the electrophotographic photosensitive member unit.

  Evaluation was performed in the same manner as in Example 1 except that the electrophotographic apparatus for evaluation was changed to a modified machine of a copying machine (trade name: IR105) manufactured by Canon Inc. having a configuration shown in FIG. At that time, the rotational speed of the electrophotographic photosensitive member unit was set as shown in Table 6, respectively. The results are shown in Table 6.

  From Tables 2 to 6, it can be seen that the effects of the present invention can be obtained even if the outer diameter of the substrate (the outer diameter of the electrophotographic photosensitive member) is different.

1000 Electrophotographic Photoreceptor Unit 1001 Electrophotographic Photoreceptor 1002 First Flange 10021 First Flange Shaft 1003 Second Flange 10031 Second Flange Shaft 10041-10044 Screw 1005 Stay 10061 First Bearing 10062 First Bearing Second bearing 1007 Input gear 10081, 1008 Inlay processing portion 1009 Output gear 1010 Longitudinal center of gravity of electrophotographic photosensitive member unit 1011 Center of longitudinal direction of electrophotographic photosensitive member unit 1012 Weight

Claims (1)

A cylindrical electrophotographic photosensitive member, and an electrophotographic photosensitive member unit having a first bearing and a second bearing for rotatably supporting both ends of the electrophotographic photosensitive member in the electrophotographic apparatus;
A rotation drive mechanism having an output gear for outputting a rotation drive force for rotating the electrophotographic photosensitive member in the electrophotographic apparatus;
A charging device having a charging roller disposed in contact with the surface of the electrophotographic photosensitive member;
An image exposure apparatus;
A developing device;
A transfer device;
An electrophotographic apparatus having a cleaning device having a cleaning blade disposed in contact with the surface of the electrophotographic photosensitive member,
The electrophotographic photosensitive unit further has an input gear that can mesh with the output gear,
The electrophotographic photosensitive member has a cylindrical base, a photoconductive layer made of amorphous silicon on the base, and a first flange and a second flange fitted to both ends of the base. ,
The first bearing is attached to the first flange, and the second bearing is attached to the second flange;
The input gear is not attached to the first flange, the input gear is attached only to the second flange,
The longitudinal length of the electrophotographic photosensitive member unit is A, and the distance from the longitudinal center of the electrophotographic photosensitive member unit to a longitudinal center of gravity of the electrophotographic photosensitive member unit was B, 0. An electrophotographic apparatus satisfying a relationship of 04 ≦ B / A ≦ 0.13 .

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