JP2014052524A - Characteristic evaluation method and characteristic evaluation device for electrophotographic photoreceptor - Google Patents

Abstract

Kind Code: A1 An electrophotographic photosensitive member characteristic evaluation method capable of determining the degree of "problem on the measuring device side" when fluctuations in the charged potential of the photosensitive member occur during measurement of the photosensitive member characteristics. provide.
A charger 6 for charging a photosensitive member 1, an exposure device 3 for exposing a charged photosensitive surface, and first and second surface potential meter probes 2 for detecting a surface potential of the photosensitive member before and after exposure. , 4 and a controller for calculating the charge amount of the photoconductor, and in a characteristic evaluation method for obtaining the capacitance of the photoconductor based on the surface potential measurement result and the charge amount calculation result, A potential difference V3 (| V2−V1 |) is obtained from the measured charging potential V1 at the position A and the predicted charging potential V2 calculated for another position B when the same passing current as the position A flows. Based on this, it is determined whether or not the charging potential has changed due to a problem on the measuring device side.
[Selection] Figure 1

Description

  The present invention relates to a characteristic evaluation method and characteristic evaluation apparatus for an electrophotographic photosensitive member used in an image forming apparatus such as a laser printer or a copying machine.

An electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member”) is one of the most important components in an image forming apparatus applying an electrophotographic process such as a copying machine or a laser printer. In order to bring out the performance of the apparatus main body, it is necessary to satisfy various characteristics. For this reason, the photoreceptor is inspected for various characteristics relating to electrophotography before shipment.
In addition, when developing a new photoconductor for use in a new electrophotographic apparatus, various characteristics relating to electrophotography of the photoconductor prototyped in the development process have been evaluated. Various evaluation devices have also been proposed.

  For example, Patent Document 1 discloses a charging device that rotatably holds a removable photosensitive drum and charges the surface of the held photosensitive drum over almost the entire region in the axial direction, and a charging position by the charging device. An exposure unit having a light source for exposing the surface of the photosensitive drum over substantially the entire region in the axial direction at a downstream position in the rotational direction of the photosensitive drum, and photosensitive drum rotating means for rotating the photosensitive drum in a predetermined direction; A potential sensor that is arranged so as to be movable in the axial direction of the photosensitive drum, and that measures the potential of the surface of the photosensitive drum downstream of the exposure position by the light source in the rotational direction of the photosensitive drum; Sensor moving means for moving the potential sensor in the axial direction of the photosensitive drum, and the photosensitive drum at a position downstream of the measurement position by the potential sensor in the rotational direction of the photosensitive drum. Substantially of the photosensitive drum having a charge removing device for discharge over the entire photoreceptor characteristic measuring device surface in the axial direction of the drum have been described.

Patent Document 2 discloses a method for evaluating the characteristics of a photoconductor, in which an operation unit equipped with at least a charging unit, an exposure unit, and a surface potential measuring unit is moved in the direction of the generatrix by moving a cylindrical photoconductor. The photosensitive member has a photoconductive layer mainly composed of amorphous silicon, the effective charging range of the charging unit is 2 to 15 cm, and the exposure unit has a variable exposure amount and exposure wavelength. To do.
Thus, an evaluation method is described in which the various characteristics described above can be evaluated comprehensively and with high accuracy.

  Further, Patent Document 3 discloses that a charging device, a static eliminator, and a surface potential meter arranged around the photoconductor are arbitrarily moved with respect to the photoconductor, so that the outer shape of the photoconductor, the linear velocity of the photoconductor, and the laser scan sub-scan A method for evaluating the characteristics of the photoconductor from the resolution in the scanning direction, the charging time, the arrangement position information in the circumferential direction of the charging device, and the surface potential of the photoconductor before and after exposure measured by a surface electrometer is described.

  Further, Patent Document 4 includes at least a charging device, an exposure device, a surface potential detection device, and an electrophotographic photosensitive member shake amount measuring device, and a predicted fluctuation amount of the charged potential predicted from the measured shake amount. A characteristic evaluation method and a characteristic evaluation apparatus are described in which ΔV1 is calculated, and the abnormality of the photoconductor is detected from the relationship between the calculated ΔV1 and the charged potential fluctuation amount ΔV2 obtained when the photoconductor characteristics are measured.

By the way, in the characteristic evaluation method described in Patent Documents 1 to 3, a scorotron charger is used to smooth the surface potential of the electrophotographic photosensitive member during characteristic evaluation, and the surface potential of the electrophotographic photosensitive member is smoothed. Is realized.
However, even when the scorotron charger is used, the photoconductor under measurement may be shaken depending on the accuracy of the support of the photoconductor and the mechanical accuracy of the measuring device.
In this case, since the distance between the photoconductor and the charger is not stable, the surface potential of the photoconductor to be measured may fluctuate even if it is a scorotron charger, which affects the measurement accuracy. There is no description about this phenomenon in ~ 3.
Patent Document 4 describes a method for evaluating the characteristics of a photoconductor when the distance between the photoconductor and the charger is not stable. In either case, a displacement sensor is used to measure the distance between the photoconductor and the charger. In addition, it is necessary to always measure the shake amount, and it is inevitable that the apparatus becomes complicated due to the installation of the displacement sensor and the system becomes complicated due to the data processing.
The present invention has been made to solve the above problems, and when measuring the characteristics of the photoconductor, if a change occurs in the charged potential of the photoconductor, the determination of how much "problem on the measuring device side" is present, An object of the present invention is to provide an electrophotographic photosensitive member characteristic evaluation method and characteristic evaluation apparatus that can perform detection at an arbitrary position and can be realized without the need for complicated apparatus and complicated system. .
Here, the "measurement device side problem" means that the photosensitive member side includes the photosensitive member rotation spindle, the deflection of the drum chuck jig, and the inclination of the photosensitive member caused by the gap between the drum chuck jig and the inner diameter of the photosensitive member. It refers to a problem that occurs due to a problem on the measuring device side, regardless of the type.

  The above-mentioned problems include, according to the present invention, “an electrostatic charging step for charging an electrophotographic photosensitive member, an exposure step for discharging the charged photosensitive surface of the electrophotographic photosensitive member by exposure, and a surface of the electrophotographic photosensitive member. A surface potential detecting step for detecting the potential of the electrophotographic photosensitive member, and a charge amount calculating step for calculating a charge amount of the electrophotographic photosensitive member, wherein the electrophotographic sensor is based on the surface potential measurement result and the charge amount calculation result. In the characteristic evaluation method for obtaining the electrostatic capacity of the photoconductor, the measured charging potential V1 at an arbitrary position A on the surface of the electrophotographic photoconductor and another position B when the same passing current as the position A flows. Can be solved by calculating the predicted charging potential V2 of the electrophotographic photosensitive member and calculating the potential difference V3 (| V2-V1 |).

  According to the present invention, it is possible to provide a characteristic evaluation apparatus capable of determining whether or not the charged potential has changed due to a problem on the measurement apparatus side when measuring the characteristics of the photosensitive member.

1 is a schematic front view showing a configuration of an electrophotographic photosensitive member characteristic evaluation apparatus according to the present invention. 1 is a schematic top view illustrating a configuration of an electrophotographic photosensitive member characteristic evaluation apparatus according to the present invention. 1 is a schematic side view showing a configuration of an electrophotographic photosensitive member characteristic evaluation apparatus according to the present invention. 6 is a graph showing a difference in average charge potential when the distance between the photoreceptor and the charger changes based on the average charge potential at a distance between the photoreceptor and charger of 1 mm. It is the graph which changed and displayed the X-axis of FIG. 4 to the shake amount. 5 is a graph showing a result of measuring a charged potential fluctuation amount and a result of measuring a distance between a displacement sensor and a photosensitive member in a pre-experiment for explaining examples. 6 is a graph showing the result of measuring the amount of change in charging potential and the result of measuring the distance between the displacement sensor and the photosensitive member in the pre-experiment for explaining the embodiment (corresponding relationship depending on the position of the charging potential measured by the probe). Graph with corrected deviation). It is a figure which shows the relationship between the electric charge amount Q and the surface potential V for calculating | requiring an electrostatic capacitance.

An embodiment of an electrophotographic photosensitive member characteristic evaluation apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic front view showing the configuration of an electrophotographic photosensitive member characteristic evaluation apparatus according to the present invention, FIG. 2 is a schematic top view, and FIG. 3 is a schematic side view.

  As shown in FIG. 1, the photosensitive member evaluation apparatus according to the present embodiment includes a charger 6 that charges the photosensitive member 1, an exposure device 3 that forms a latent image, and a static eliminator 5 of a drum-shaped photosensitive member 1. A first surface potentiometer probe 2 which is a surface potential detector arranged around and between the charger 6 and the exposure device 3 and between the exposure device 3 and the charge eliminator 5 to measure the surface potential on the photoreceptor. And the 2nd surface electrometer probe 4 is an apparatus each arrange | positioned.

In this evaluation apparatus, after the photosensitive member 1 is charged, an electrostatic latent image is formed at the timing of charging and exposure ON / OFF so that the exposure is performed when the charging start position reaches the exposure position 3. The post-exposure potential V1 and the post-discharge potential V2 can be compared by using the static eliminator 5 for evaluation.
The second surface electrometer probe 4 can adjust the angle so that the time from the exposure apparatus 3 can be set arbitrarily.
The surface electrometer probes 2 and 4 are preferably installed at the same position in the axial direction (for example, preferably in the same position in the axial direction in FIG. 3).

As shown in FIG. 2, the exposure apparatus 3 has a mechanism in which the light from the laser diode 8 is exposed to the axial direction side of the photosensitive member 1 by the polygon mirror 10.
In addition, an ND filter (neutral density filter) 7 capable of adjusting the exposure amount to be exposed to the photoreceptor 1 is disposed between the laser diode 8 and the polygon mirror 10, and the ND filter 7 is used. It is possible to perform exposure with the exposure energy required at the time of exposure.
It is preferable that a plurality of ND filters 7 are arranged. By arranging a plurality of ND filters 7, it is possible to greatly change the exposure conditions.
Further, a rotary solenoid 9 is arranged for operating the ND filter 7.

As shown in FIG. 3, in this characteristic evaluation apparatus, the photosensitive drum 1 is held at both ends by the drum chuck jig 15, and the main shaft 13 passes through the center of the drum chuck jig 15.
In the main shaft 13, a face plate 17 disposed on the left side of the photosensitive drum 1 in FIG. 3 and a face plate 16 disposed on the right side of the photoconductor 1 constitute a bearing mechanism for the main shaft 13, and the main shaft 13 is connected to the motor 11. The mechanism is rotated by the belt 14 and rotates in the direction of the arrow in FIG.

  The current passing through the photosensitive drum 1 during charging is measured and sent to the signal processing circuit 18 (a smoothing circuit (not shown) is incorporated in the signal processing circuit 18, and the passing current is passed by the smoothing circuit. Is smoothed.) Thereafter, it is converted into a digital signal by the A / D converter 19 and sent to the controller 12, where the digital signal is processed. The calculation of the charge amount and the calculation of the capacitance are performed by the controller.

The motor driver in the motor 11 that rotates the photosensitive member 1 is also provided with a function for outputting the rotational speed, a position detecting function, and a function for remotely controlling the rotational speed, and the rotational speed control and the rotational speed recognition and setting. It is also possible to stop the drum at the angle and rotate it at an arbitrary linear velocity v.
In FIG. 1, r represents the radius of the photosensitive drum diameter.

In this evaluation apparatus, it is possible to degrade the photoreceptor 1 by repeating the charging process by the charger 6 and the exposure process by the exposure apparatus 3 a predetermined number of times, and the post-exposure potential V1 before degradation and the post-exposure potential V2 after degradation. Can also be evaluated.
As the charger 6 used in the present invention, a corotron charger or a scorotron charger which is a corona charger can be used, but a scorotron charger which is uniform and can easily reach a predetermined potential is preferable.
Although not shown in the charger 6, it is a mechanism capable of charging the photosensitive member 1 by a high voltage power source individually connected to a wire and a grid.

The charger 6, exposure device 3, static eliminator 5, and surface potential meter probes 2, 4 have a structure that can advance and retreat in the radial direction of the photoreceptor 1 so that it can be arranged at a certain distance from the surface of the photoreceptor drum 1. Therefore, it can cope with various outer diameters of the photoreceptor 1.
Further, these units are structured to be movable in the axial direction, and can be measured at an arbitrary position in the axial direction of the drum.
Further, the units around the photosensitive member 1 can be controlled to be turned on / off by a digital relay output of a signal processing circuit (not shown).

Although the control means for the charging device power supply circuit of the charger 6 and the control means for the light source power supply circuit of the exposure apparatus 3 are not shown, conventionally known ones can be used as they are.
The characteristic evaluation apparatus is covered with a dark box that does not transmit light, or a black curtain.
If it is not covered with a dark box or a black curtain, it will be affected by the external environment (wind, light, temperature) during testing, making accurate characterization difficult.
However, a controller, a signal processing circuit, or the like that does not affect the evaluation of the photosensitive drum does not need to be covered with a dark box or a black curtain.

As the photoconductor used in the practice of the present invention, those in which a charge generation layer and a charge transport layer are formed on a conductive support, and those in which a protective layer is formed on the charge transport layer are used.
As the conductive support, the charge generation layer, and the charge transport layer, known ones can be used.
As the charger 6 used in the present invention, a corona charger or a scorotron charger which is a corona charger can be used.

Regarding the capacitance calculation method, the capacitance of the photoreceptor is calculated from the relationship between the surface potential and the passing current.
In the calculation, first, the charge amount Q is calculated from the passing current I using the following equation (I).
Q = I / (W · vp) (I)
(In formula (I), Q represents the charge amount [C / mm ² ], I represents the passing current [A], W represents the effective charging width [mm] of the charging device, and vp [mm / s]. Indicates the linear speed (rotational speed) of the photoreceptor.)
The charge amount to _{Q 1} photoreceptor 1 _lap, Q 1 _{= I} a _{1 / (W × vp) (} I 1: Current any one point of the first turn), the photosensitive member 2 lap subsequent charge the amount Qn (n: number of revolutions) _{is, Q n = I n / (} W × vp) + Q n-1 (I n: the desired point of n-th revolution _{current, Q n-1: n-} 1 lap Charge amount Q is calculated by (charge amount).

From the charge amount Q and the surface potential V thus obtained, the capacitance C [F / mm ² ] is obtained by the following equation (II).
Q = C · V (II)
(In formula (II), Q represents the amount of charge [C / mm ² ], V represents the surface potential [V], and C represents the capacitance [F / mm ² ]. ”

The electrostatic capacity can be calculated from one charge amount Q and the surface potential V. However, in order to improve the electrostatic capacity calculation accuracy, the electrostatic capacity is determined from the relationship between the plurality of charge amounts Q and the surface potential V. Is preferably calculated.
Thereby, the electrostatic capacitance C of the photosensitive member can be obtained. Further, with respect to the surface potential V, the initial surface potential V4 before sub-measurement can be subtracted to calculate the capacitance in consideration of the potential change corresponding to the charge amount change. Since V4 is preferably subtracted, and the surface electrometer probe and the charging device are not at the same position, the relationship between the current and the surface potential has a time difference corresponding to a shifted angle in the layout. Therefore, it is preferable that the correspondence between the surface potential and the passing current is performed in consideration of the time difference corresponding to the angle deviation.

  In the electrophotographic photoreceptor evaluation method and evaluation apparatus of the present invention, the capacitance at an arbitrary position can be obtained by performing the capacitance calculation for each drum rotation time. In this case, first, the amount of charge Q is calculated from the passing current at a certain position using the above formula (I), and then the surface potential and the amount of charge for each drum rotation time are shown on the horizontal axis as shown in FIG. Plotting on a graph with the quantity Q and V on the vertical axis, and obtaining the capacitance from the slope of the straight line L2 connecting a plurality of plot points.

  In order to obtain the capacitance with higher accuracy, the capacitance is obtained not by the slope of L1 connected by one plot but by the slope of L2 calculated from a plurality of plots. Furthermore, the capacitance distribution can be obtained by performing the capacitance calculation at a plurality of positions. Here, the surface potential difference for each drum rotation is preferably calculated based on the result that a potential difference of about 100 V occurs even once because the error in capacitance calculation increases when the potential difference is small. Furthermore, regarding the charge amount at the time of calculating the capacitance, the charge amount after the second round of the photoconductor is calculated by adding the charge amount before the first round, thereby taking into account the total charge amount at the reached surface potential. Since the electrostatic capacity can be calculated in the above-described form, the charge amount after the second round of the photoreceptor is calculated by adding the charge amount from the previous round.

First, prior to the description of the embodiments, a characteristic evaluation apparatus and a characteristic evaluation method for an electrophotographic photosensitive member in “prior art” will be described.
1 is an apparatus for evaluating the characteristics of an electrophotographic photosensitive member having the same configuration as in FIGS. 1 to 3, and a photosensitive drum (drum diameter 100 mm, drum total length 360 mm, drum wall thickness 1.2 mm, drum weight 362 g) mounted on a Ricoh imgio MF7070. ) Was used to evaluate the characteristics.
The high voltage power source, the surface potential meter, and the surface potential meter probes 2 and 4 connected to the charger 6 were manufactured by TREK.

  The charger 6 is an in-house manufactured scorotron charger, the static elimination light source (static neutralizer) 5 is a line LED with a wavelength of 660 nm, the motor 13 is an Oriental motor, and all other signal processing circuits are manufactured in-house. An evaluation device was used. Further, in order to measure the distance between the charger and the photoconductor, a non-contact eddy current displacement sensor manufactured by Keyence Corporation was installed at the same radial angle as the charger.

The photosensitive member linear velocity is 244 mm / s, and the discharge voltage is such that the average charge potential for the peripheral length of the photoconductor measured by the surface potential meter probe 2 is −800 V, and between the photoconductor and the charger (charger). FIG. 4 shows the difference in the charging potential when the average value of the charging potential for the circumference of the photoconductor is measured and the distance between the photoconductor and the charger is 1 mm.
Note that the measurement position in the axial direction of the photosensitive member was the central portion of the photosensitive member.
Since the variation between the photosensitive member-charger distance can be regarded as the same as the change in the shake amount of the photosensitive member, FIG. 4 can be regarded as the amount of change in the charged potential when the shake amount changes. .
Therefore, it can be seen that the larger the shake amount, the larger the charged potential fluctuation amount.
FIG. 5 shows the result when the X-axis of FIG. 4 is converted as the shake amount.
From the results of FIG. 5, it can be seen that the amount of fluctuation of the charging potential increases as the amount of shake increases.

  Next, the photosensitive member is charged with a discharge voltage such that the average charged potential of the photosensitive member circumference measured by the first surface potential meter probe 2 is −800 V, with a photosensitive member linear velocity of 244 mm / s, and the photosensitive member. FIG. 6 shows a graph of the result of measuring the charging potential when charging 942 mm, which is three times the circumference, and the result of measuring the distance between the displacement sensor and the photosensitive member by the displacement sensor.

In FIG. 6, the photosensitive member radial direction angle is set at a position where the angle between the displacement sensor and the charged potential measuring probe (surface potential meter probe) 2 is different by 45 degrees. The charge potential is measured at a time delayed by 45 degrees.
Therefore, FIG. 7 shows a result obtained by changing the charging potential result so that the correspondence between the charging potential and the shake amount can be confirmed by calculating the result by shifting the time of 45 degrees earlier.
Note that the measurement position in the axial direction of the photosensitive member was the central portion of the photosensitive member.

From the results of FIG. 7, the distance between the displacement sensor and the photoconductor is not constant but varies. Therefore, it can be seen that the photoconductor is shaken during the measurement. In addition, the charging potential of the photosensitive member increases as the distance decreases, and the charging potential of the photosensitive member decreases as the distance increases. Therefore, the shake of the photosensitive member greatly affects the charging potential. It can be seen that when the fluctuation amount of is large, there is a case where the fluctuation amount of the charging potential is large due to the influence of the shake of the photoconductor.
Therefore, it can be understood that it is important to distinguish and determine whether the charged potential fluctuation amount of the photosensitive member is due to characteristics of the photosensitive member or a problem due to setting such as shake.

From the results of FIG. 5 and FIG. 7, even when the charging potential fluctuation amount is large, it is also influenced by the large amount of rotation fluctuation. Conventionally, the problem of the photoconductor is determined only by the charging potential fluctuation amount. However, it can be seen that the conventional determination method cannot perform measurement in a state where the influence of shake during rotation caused by setting problems such as shake is eliminated.
To solve this problem, there is a method to constantly measure and confirm the distance between the photoconductor and the charger using a displacement sensor. However, it is necessary to attach the displacement sensor and process the results measured by the displacement sensor. A mechanism to do this is required.

In the present invention, the measured charging potential V1 at an arbitrary position A on the surface of the electrophotographic photosensitive member and the predicted charging potential V2 calculated for another position B when the same passing current as the position A flows are used. The potential difference V3 (| V2-V1 |) is obtained. The predicted charging potential V2 can be calculated from the capacitance at the position B.
Based on the value of the potential difference V3, it is possible to determine whether or not the charging potential has changed due to a problem on the measurement device side.
As a result of investigation by the present inventors, there is no relationship between the measured charging potential V1 and the shake amount, and the measured charging potential V1 is a charging potential that includes the influence of the shake and the problem of the photoconductor.
On the other hand, the relationship between the potential difference V3 and the shake amount is related to the fact that the greater the potential difference V3, the greater the shake amount.
Therefore, it can be seen that the potential difference V3 does not include the charging potential difference caused by the characteristics of the photoconductor, and predicts the charging potential difference caused by the problem on the measuring apparatus side. From this, by calculating the potential difference V3 between the measured charged potential V1 and the predicted charged potential V2, it is possible to grasp the charged potential difference caused by the problem on the measuring device side without installing the shake amount measuring device.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by these Examples.

Next, Example 1 will be described.
Photoreceptor coated with a photosensitive layer of the same material and formulation as the photoconductive drum mounted on Ricoh imgio MF7070, using the same characteristic evaluation apparatus as in FIGS. 1 to 3 (using an evaluation apparatus designed and manufactured in-house) Characteristic evaluation was performed using a drum (drum diameter 100 mm, drum total length 360 mm).
Table 1 shows the result of calculating the capacitance from the surface potential and the passing current result at four points (0 °, 90 °, 180 °, 270 °) in the circumferential direction of the photosensitive member at a position 180 mm in the drum axis direction. The capacitance was calculated from data from the start of charging to the third round.

  Next, using the passing current measurement result Ia (data when charged to the vicinity of 800 V) at the circumferential position 0 ° of the photosensitive member, the passing current is Ia at other points (90 °, 180 °, 270 °). Table 1 shows the results obtained by calculating the predicted charging potential V2 at each point based on the assumption from the capacitance and the equations (I) and (II). Further, Table 1 shows a potential difference V3 (| V2-V1 |) between the measured charging potential V1 and the predicted charging potential V2.

The high voltage power source, surface potential meter, and surface potential meter probes 3 and 17 connected to the charger 6 were manufactured by TREK.
The charger 6 is an in-house manufactured scorotron charger, the static elimination light source (static neutralizer) 5 is a line LED with a wavelength of 660 nm, the motor 13 is an Oriental motor, and all other signal processing circuits are manufactured in-house. A characterization device was used.
The evaluation conditions were as follows.
Drum rotation speed: 200rpm
Surface potential / passing current sampling interval: 0.01 sec
Distance between charger and photoconductor: 1mm
Set discharge current; -127.3 [nA / cm ² ]
With respect to the potential difference at the rotational speed of the photosensitive member under these conditions, the potential difference between the first and second rounds of the drum is about 150 V and the potential difference between the second and third rounds of the drum is about 110 V. .
Moreover, the electrostatic capacitance was calculated | required based on the calculation method of Formula (I), Formula (II), and FIG.

However, for all surface potentials when calculating the capacitance, a value obtained by subtracting the initial surface potential was used, and for the calculation of the charge amount, a value obtained by adding the charge amount of the previous round was used as the charge amount. .
In order to measure the distance between the charger and the photosensitive member, a non-contact eddy current displacement sensor manufactured by Keyence Corporation was installed at the same radial angle as the charger, and measurement was performed in advance. The results are shown in Table 1. However, at the time of confirmation in Example 1, the measurement was performed with the displacement sensor removed.

From the results shown in Table 1, there is no relationship between the measured charging potential value V1 and the shake amount, and the charged potential measured value V1 is a charging potential that includes the influence of shaking and problems with the photoconductor. On the other hand, the relationship between the potential difference V3 and the shake amount is related to the fact that the greater the potential difference V3, the greater the shake amount.
Therefore, it can be seen that the potential difference V3 does not include the charging potential difference caused by the characteristics of the photoconductor, and predicts the charging potential difference caused by the problem on the measuring apparatus side. From this, by calculating the potential difference V3 between the measured charged potential V1 and the predicted charged potential V2, it is possible to grasp the charged potential difference caused by the problem on the measuring device side without installing the shake amount measuring device.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 2 1st surface potential meter probe 3 Exposure apparatus 4 2nd surface potential meter probe 5 Charger 6 Charger 7 ND filter 8 Laser diode 9 Rotary solenoid 10 Polygon mirror 11 Motor 12 Controller 13 Main shaft 14 Belt 15 Drum chuck jig 16 Face plate 17 Face plate 18 Signal processing circuit 19 A / D converter

Japanese Patent Laid-Open No. 4-26852 JP 2003-29572 A JP 2000-275872 A JP 2010-117580 A

Claims (4)

  An electrostatic charging step for charging the electrophotographic photoreceptor, an exposure step for removing the charged surface of the electrophotographic photoreceptor after charging by exposure, and a surface potential detection for detecting the surface potential of the electrophotographic photoreceptor. A charge amount calculating step of calculating a charge amount of the electrophotographic photoreceptor, and obtaining a capacitance of the electrophotographic photoreceptor based on the surface potential measurement result and the charge amount calculation result. In the characteristic evaluation method, the measured charging potential V1 at an arbitrary position A on the surface of the electrophotographic photoreceptor, and the predicted charging potential V2 calculated for another position B when the same passing current as the position A flows. A method for evaluating the characteristics of an electrophotographic photosensitive member, characterized in that a potential difference V3 (| V2-V1 |) is obtained from the difference.   2. The method for evaluating characteristics of an electrophotographic photosensitive member according to claim 1, wherein the predicted charging potential V2 is calculated from an electrostatic capacity at the position B.   The method for evaluating characteristics of an electrophotographic photosensitive member according to claim 1, wherein the presence or absence of a problem with the characteristic evaluation apparatus is determined based on the potential difference V 3.   An electrostatic charging device that charges the electrophotographic photoreceptor, an exposure device that neutralizes the photosensitive surface of the electrophotographic photoreceptor after charging, and a surface potential detection that detects the surface potential of the electrophotographic photoreceptor. And a charge amount calculation device for calculating a charge amount of the electrophotographic photoreceptor, and obtaining a capacitance of the electrophotographic photoreceptor based on the surface potential measurement result and the charge amount calculation result. In the characteristic evaluation apparatus, the measured charging potential V1 at an arbitrary position A on the surface of the electrophotographic photoreceptor, and the predicted charging potential V2 calculated for another position B when the same passing current as the position A flows. An apparatus for evaluating characteristics of an electrophotographic photosensitive member, characterized in that a potential difference V3 (| V2-V1 |) is obtained from the above.

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