JP5447838B2 - Electrophotographic photoconductor characteristic evaluation device - Google Patents

Description

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

  An electrophotographic photosensitive member in an image forming apparatus such as a laser printer or a copying machine is exposed to a predetermined image after its surface is uniformly charged, thereby forming an electrostatic latent image on the surface of the photosensitive member. This electrostatic latent image is developed with toner. In order to form a clear image on the surface of the photoreceptor, it is necessary to charge the surface of the photoreceptor uniformly, and it is necessary to inspect whether or not the entire drum has uniform charging characteristics.

  In Patent Document 1, a detachable photosensitive drum is rotatably held, a charging device that charges the held surface of the photosensitive drum over almost the entire region in the axial direction, and a photosensitive member from a charging position by the charging device. An exposure unit having a light source that exposes the surface of the photosensitive drum over substantially the entire axial direction at a position downstream of the rotation direction of the drum, photosensitive drum rotating means for rotating the photosensitive drum in a predetermined direction, A potential sensor which is arranged so as to be movable in the axial direction of the photosensitive drum, and which 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 sensor in the axial direction of the photosensitive drum, and the position of the photosensitive drum at a position downstream of the measurement position by the potential sensor in the rotational direction of the photosensitive drum. Photoreceptor characteristic measurement apparatus of a photosensitive drum having a charge removing device which neutralizes the surface over substantially the entire region in the axial direction is described.

  However, the technique described in Patent Document 1 has the following problems. After measuring the charging potential at the initial position in the drum axis direction, the charging device, the potential sensor, and the neutralization device were moved to the next position in the axial direction, and the charging potential at the next position was measured. The measurement of the charged potential at the next position is affected by the potential measurement at the position, which may be a factor that reduces the measurement accuracy when evaluating the axial potential distribution of the photoreceptor. However, there was no description or suggestion regarding this point, and it was not recognized as a problem.

  An object of the present invention is to provide an apparatus for evaluating characteristics of an electrophotographic photoreceptor capable of solving the above-described problems and measuring the charged potential in the drum axis direction of the electrophotographic photoreceptor with high accuracy. .

The above problem is solved by the following invention.
(1) The electrophotographic photosensitive member includes a surface potential detecting unit in which n (n is an integer, n ≧ 2) surface potential detecting units are arranged in the axial direction of the charging unit, the neutralizing unit, and the electrophotographic photosensitive drum. When measuring the charging potential distribution in the axial direction of the body drum, after simultaneously measuring the charging potential at any n locations in the axial direction, the one end A to the other end of the electrophotographic photosensitive drum Move the charging means, the static eliminating means, and the surface potential detection unit toward B by a distance n-1 times the interval between the two surface potential detection means, and simultaneously measure the charged potentials at n locations. The difference between the detection results of the surface potential detection means closer to the end portion A and the surface potential detection means closer to the end portion B before the movement is calculated, and it is determined whether or not it is within a predetermined range. An apparatus for evaluating characteristics of an electrophotographic photoreceptor,
When the difference between the detection results of the surface potential detection means closer to the end A after the movement and the surface potential detection means closer to the end B before the movement is within a predetermined range, The charging means, the charge eliminating means, and the surface potential detecting unit are moved toward the end B in the direction by a distance that is n-1 times the two intervals of the surface potential detecting means, so that n charged potentials are simultaneously measured. Then, the detection result is discriminated by the same discrimination method, and if the difference in the detection result is out of the predetermined range, the one end A of the electrophotographic photosensitive drum is connected to the other end. Moving toward the portion B, the charging means, the static elimination means, and the surface potential detection unit are moved again by a distance of n + m times (m is an integer, m ≧ 1) the interval between the two surface potential detection means, Simultaneously measure the charging potential, the surface potential before the movement From the detection result of the output means and the detection result of the surface potential detection means after re-moving, the charge potential value of the unmeasured area in the axial direction is calculated and interpolated, and further the surface potential is detected toward the end B in the axial direction The charging means, the static elimination means, and the surface potential detection unit are moved by a distance n-1 times the two intervals of the means, and the n charged potentials are simultaneously measured, and the detection results are discriminated by the same discrimination method. An apparatus for evaluating characteristics of an electrophotographic photoreceptor, characterized in that it is provided .
( 2 ) Interpolation of the value of the charged potential in the unmeasured area in the axial direction is performed by detecting the surface potential detection means closer to the end B before the movement and the one closer to the end A after the re-movement. A linear function representing the relationship between the position in the axial direction and the charging potential is obtained from the detection result of the surface potential detection means, and the charging potential value of the unmeasured region in the axial direction is calculated from the obtained linear function. ( 1 ) The electrophotographic photosensitive member property evaluation apparatus according to ( 1 ).
( 3 ) The operation for discriminating the detection result is repeatedly performed from the end A to the end B of the electrophotographic photoreceptor, and the characteristics in a predetermined region in the axial direction of the electrophotographic photoreceptor are evaluated. The apparatus for evaluating characteristics of an electrophotographic photoreceptor according to ( 1 ) or ( 2 ), characterized in that it is configured as described above.
( 4 ) A method for evaluating the characteristics of an electrophotographic photoreceptor, comprising evaluating the characteristics of the electrophotographic photoreceptor using the characteristic evaluation apparatus according to any one of (1) to ( 3 ).

The electrophotographic photosensitive member characteristics of the present invention comprising a surface potential detecting unit in which n (n is an integer, n ≧ 2) surface potential detecting means are arranged in the axial direction of the charging means, the static eliminating means, and the electrophotographic photosensitive drum. In the evaluation apparatus, the surface potential detection means closer to the end A after moving the charging means, the charge removal means, and the surface potential detection unit by n−1 times the interval between the two surface potential detection means and the pre-movement If the difference in the detection results of the surface potential detection means closer to the end B of the surface is greater than or equal to a predetermined value, the surface potential detection means is moved to a position where it is not affected by the measurement effect before the movement (the effects of charging and static elimination). The drum axis is re-moved, and the charge potential value of the unmeasured area in the axial direction is calculated and interpolated from the detection result of the surface potential detection means before the movement and the detection result of the surface potential detection means after the movement. Before moving when measuring the charged potential distribution in the direction Effect of the measurement it is possible to measure in the form free from the (influence of charging and charge elimination).
Therefore, if this evaluation device is used, it is possible to eliminate the measurement error after the movement caused by the influence of the measurement before the movement in the axial direction, which has been a problem in the conventional evaluation device, and the charging in the drum axis direction can be eliminated. It becomes possible to evaluate the potential distribution characteristics with high accuracy.
Further, by repeatedly performing such characteristic evaluation from the end A to the end B of the electrophotographic photoreceptor in a predetermined region in the drum axis direction, the characteristic evaluation in the predetermined region in the drum axis direction is performed. Can be carried out in a manner that is not affected by the measurement prior to movement (effects of charging and static elimination).

It is an example of the schematic of the front of the electrophotographic photoreceptor characteristic evaluation apparatus of this invention. It is an example of the schematic of the side surface of the photoreceptor characteristic evaluation apparatus for electrophotography of this invention. It is a figure showing the range ag. It is the charging potential distribution in the axial direction of the electrophotographic photoreceptor 2 created based on the measurement results in Comparative Example 1 and Example 1. The vertical axis represents the VD difference with respect to the reference VD. The horizontal axis represents the measurement position (distance from the end A) of the electrophotographic photoreceptor in the axial direction. It is a figure showing the range hm. 3 is a graph showing an example of the relationship between the measurement position (distance from the end A) in the axial direction of the electrophotographic photoreceptor 1 and the charging potential, and a linear function calculated from the graph. The vertical axis represents the VD difference with respect to the reference VD of the electrophotographic photosensitive drum. The horizontal axis represents the measurement position (distance from the end A) in the axial direction. 3 is a charge potential distribution in the axial direction of the electrophotographic photoreceptor 1 created based on the measurement and interpolation results in Comparative Example 2 and Example 2. FIG. The vertical axis represents the VD difference with respect to the reference VD. The horizontal axis represents the position in the axial direction of the electrophotographic photoreceptor.

(Electrophotographic photoconductor characteristic evaluation device)
The electrophotographic photoreceptor characteristic evaluation apparatus of the present invention has at least a charging means, a surface potential detection means unit, and a static elimination means, and further has other configurations as necessary.

<Charging means>
The charging means is means for charging the surface of the electrophotographic photoreceptor.
Examples of the charging means include non-contact charging means using a corona charging method such as a corotron charging method and a scorotron charging method. Among these, the scorotron charging type charger is preferable because of high controllability of the charging potential.
The charging means is provided so as to be movable in the axial direction of the electrophotographic photoreceptor. Further, the charging means has a structure capable of moving forward and backward independently in the radial direction of the electrophotographic photosensitive member. The distance from the electrophotographic photosensitive member can be adjusted, and the electrophotographic photosensitive members having various drum diameters can be adjusted. It is preferable in that it can correspond to the body.

<Surface potential detection means>
The surface potential detecting means unit is a unit for detecting at least one of a charging potential of the electrophotographic photoreceptor before exposure and a post-exposure potential of the electrophotographic photoreceptor after exposure. A unit for detecting the charged potential of the electrophotographic photoreceptor before exposure must be provided, but a unit for detecting the post-exposure potential of the electrophotographic photoreceptor after exposure is determined by the exposing means. It is only necessary to perform exposure and measure the post-exposure potential.

  The surface potential detection unit is not particularly limited as long as it can monitor at least one of the charged potential and the post-exposure potential of the electrophotographic photoreceptor, and is appropriately selected according to the purpose. Can do. Further, the surface potential detecting means includes a contact type and a non-contact type, but a contact type is preferable because it may damage the electrophotographic photoreceptor.

  The method for monitoring at least one of the charged potential and the post-exposure potential of the electrophotographic photoreceptor is not particularly limited and can be appropriately selected according to the purpose. For example, the electrophotographic photoreceptor After being charged by the charging means or exposed by an exposure means to be described later, at least one of a charging potential and a post-exposure potential of the electrophotographic photoreceptor is measured by the surface potential meter probe unit, and the surface potential meter Examples include a method of monitoring at least one of a charging potential and a post-exposure potential of the electrophotographic photoreceptor by sending a signal to the unit.

  The surface potential detecting means unit is provided so as to be movable in the axial direction of the electrophotographic photoreceptor. Further, the surface potential detecting means unit has a structure capable of being independently advanced and retracted in the radial direction of the electrophotographic photosensitive member, and the distance from the electrophotographic photosensitive member can be adjusted. This is preferable in that it can be applied to a photographic photoreceptor.

  The greater the number of surface potential detection means, the greater the range that can be measured at one time when measuring the axial characteristics of the electrophotographic photoreceptor, leading to a reduction in measurement time. Is concerned about the problem. Therefore, the number of the surface potential detecting means is at least two, and it is sufficient that they are arranged side by side in the axial direction of the electrophotographic photoreceptor. When exposure is performed by an exposure apparatus, the number of surface potential detection means after exposure needs to be equal to the number of surface potential detection means after charging. When the number of the surface potential detecting means is three or more, it is preferable that the arrangement intervals of the surface potential detecting means are equal.

<Static removal means>
The charge eliminating means is a means for eliminating the charge potential of the electrophotographic photoreceptor. The neutralization means is not particularly limited as long as the electrophotographic photoreceptor can be neutralized, and can be appropriately selected from known neutralization means. Examples thereof include a neutralization lamp.
The neutralizing means is provided so as to be movable in the axial direction of the electrophotographic photoreceptor. Further, it is possible for the static eliminating means to have a structure capable of moving forward and backward independently in the radial direction of the electrophotographic photosensitive member, so that the distance from the electrophotographic photosensitive member can be adjusted, and the electrophotographic photosensitive members having various drum diameters can be adjusted. It is preferable in that it can correspond to the body.

<Other configurations>
Examples of the other configuration include an exposure unit, a wire electrode and a grid electrode for supplying a voltage to the charging unit, a high voltage power source for the wire, a power source for the grid, a power switch for the high voltage power source, and a power switch for the power source. .

-Exposure means-
The exposure means is means for exposing the electrophotographic photoreceptor. The exposure means is not particularly limited as long as it can expose the electrophotographic photoreceptor, and can be appropriately selected according to the purpose.
The light source of the exposure means is not particularly limited and may be appropriately selected according to the purpose. For example, a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD) ), And general luminescent materials such as electroluminescence (EL). In addition, the exposure means irradiates the electrophotographic photosensitive drum only with light in a desired wavelength range, so that a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, a color temperature, Various filters such as a conversion filter can be used, and a neutral density filter can also be used to reduce the illuminance.
The exposure means is provided so as to be movable in the axial direction of the electrophotographic photoreceptor. Further, the exposure means has a structure capable of moving forward and backward independently in the radial direction of the electrophotographic photosensitive member, and the distance from the electrophotographic photosensitive member can be adjusted, so that the electrophotographic photosensitive members having various drum diameters can be adjusted. It is preferable in that it can correspond to the body.

-High voltage power supply, power supply, and power switch-
There is no restriction | limiting in particular as said high voltage | pressure power supply, a power supply, and a power switch, According to the objective, it can select suitably.
The control means for the high-voltage power supply, power supply, and power switch is not particularly limited, and conventionally known ones can be used as they are.

-Photoconductor for electrophotography-
The material, shape, size, structure and the like of the electrophotographic photoreceptor are not particularly limited and can be appropriately selected depending on the purpose.
Examples of the shape include a drum shape, a sheet shape, and an endless belt shape. Among these, a drum shape is preferable.
Examples of the material include inorganic photoreceptors such as amorphous silicon, selenium, CdS, and ZnO; organic photoreceptors (OPC) such as polysilane and phthalopolymethine, and the like.
The size can be appropriately selected according to the size, specifications, etc. of the electrophotographic photoreceptor characteristic evaluation apparatus.

The organic photoreceptor (OPC) has (1) optical characteristics such as a wide light absorption wavelength range and a large amount of light absorption, (2) electrical characteristics such as high sensitivity and stable charging characteristics, (3) In general, it is widely applied because of the wide selection range of materials, (4) ease of production, (5) low cost, and (6) non-toxicity. The layer structure of such an organic photoreceptor is roughly divided into a single layer structure and a laminated structure.
The single-layered photoreceptor has a support and a single-layer type photosensitive layer provided on the support, and further includes a protective layer, an intermediate layer, and other layers as necessary.
The laminated structure of the photoreceptor comprises a support, and a laminate type photosensitive layer having at least a charge generation layer and a charge transport layer in this order on the support, and further includes a protective layer and an intermediate layer as necessary. And other layers.

-Moving means-
The moving means is means for moving the charging means in the axial direction of the electrophotographic photoreceptor. The moving means simultaneously moves the surface potential detecting means, the exposing means, and the charge eliminating means to the same axial position corresponding to the movement of the charging means in the axial direction of the electrophotographic photoreceptor. A design is preferred. Thereby, it is possible to measure the characteristics of a desired position in the axial direction.
There is no restriction | limiting in particular as said moving means, It can select suitably from well-known moving means, For example, a stepping motor etc. are mentioned.

  Here, the electrophotographic photoreceptor characteristic evaluation apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram of the front of the electrophotographic photoreceptor characteristic evaluation apparatus of the present invention, and FIG. 2 is a schematic side view of the electrophotographic photoreceptor characteristic evaluation apparatus of the present invention. In addition, these schematic diagrams are examples and are not limited thereto.

  1 includes a scorotron charger as a charging means 6 for charging the electrophotographic photosensitive drum 1, a high voltage power source 7 for supplying a voltage to the wire electrode of the scorotron charger, and a scorotron. A power source 12 for supplying a voltage to the grid electrode of the charger, a high-voltage power source 7 and a power switch 15 of the power source 12, and a surface potential meter probe which is a surface potential detecting means for measuring the charged potential of the electrophotographic photosensitive drum 1 N surface potential meter probe units 13 arranged in the axial direction, exposure means 2 for exposing the electrophotographic photosensitive drum 1, and surface potential as surface potential detecting means for measuring the post-exposure potential of the electrophotographic photosensitive drum 1. It has a surface light meter probe unit 3 in which n meter probes are arranged in the axial direction, and a static elimination light source which is a static elimination means 8 for neutralizing the electrophotographic photosensitive drum 1. .

  The charging means 6 (scorotron charger), the surface potential meter probe unit 13, the exposure means 2, the surface potential meter probe unit 3, and the charge removal means 8 (charge removal light source) are arranged in the radial direction of the electrophotographic photosensitive drum 1. It has a structure that can advance and retreat in the axial direction, and each can be moved individually in the radial direction and can be arranged at individual positions. However, with respect to the axial direction, all of these move simultaneously and are arranged at the same axial position.

  In this electrophotographic photoreceptor characteristic evaluation apparatus, the electrophotographic photoreceptor drum 1 shown in FIG. 2 is held in the electrophotographic photoreceptor characteristic evaluation apparatus by drum chuck jigs 20 at both ends, and the spindle 18 is chucked. It passes through the center of the jig 20. A main plate is a face plate 21 on the front side (one end side of the electrophotographic photosensitive drum 1) and a face plate 22 on the back side (the other end side of the electrophotographic photosensitive drum 1) of the electrophotographic photoconductor characteristic evaluation apparatus. 18, and the main shaft 18 is a mechanism that rotates in the direction of the arrow in FIG. 1 by a belt 19 connected to the motor 16. The rotation angle of the electrophotographic photosensitive drum 1 is measured by a rotary encoder 11 attached to the end of the main shaft 18 shown in FIG. 2, and information on the rotation angle of the electrophotographic photosensitive drum 1 is shown in FIG. It is sent to the controller 17. Voltage is output from the high-voltage power supply 7 to the wire electrode of the scorotron charger, and from the power supply 12 to the grid electrode of the scorotron charger, and the electrophotographic photosensitive drum 1 is charged by the scorotron charger.

  Further, as shown in FIG. 1, the charged potential of the electrophotographic photosensitive drum 1 is sent from the surface potential meter probe unit 13 to the surface potential meter unit 14 which is a monitor unit, monitored, and sent to the signal processing circuit 9. . After that, A / D conversion is performed by the A / D converter 10 and sent to the controller 17 for arithmetic processing.

  The passing current in the electrophotographic photosensitive drum 1 is sent to the controller through the signal processing circuit 5 and the A / D converter 10, and the passing current can be grasped. The controller 17 is connected to a motor driver (not shown) in the motor 16 that rotates the electrophotographic photosensitive drum 1. In the motor driver, a function for outputting the number of revolutions and a function for remotely controlling the number of revolutions are added, so that the number of revolutions can be controlled and the number of revolutions can be recognized.

  Units around the electrophotographic photosensitive drum 1 (the scorotron charger, the surface potential meter probe unit 13, the exposure means 2, the surface potential meter probe unit 3, and the light source for charge removal) are turned ON / OFF by a digital relay output 23. It is controlled. Further, the exposure means 2 is used to expose the electrophotographic photosensitive drum 1, and the post-exposure potential of the electrophotographic photosensitive drum 1 uses the surface potential meter probe unit 3 and the surface potential meter unit 4. Thus, the charge potential after being charged by the charging means 6 can be measured in the same manner. When the post-exposure potential of the electrophotographic photosensitive drum 1 is removed, it can be removed by using a static elimination means 8 (light removal light source), such as charging characteristics and light attenuation characteristics of the electrophotographic photosensitive drum 1. Can be evaluated.

  The electrophotographic photosensitive member property evaluation apparatus is preferably covered with a dark box or black screen that does not transmit light. If the electrophotographic photosensitive member characteristic evaluation apparatus is not covered with a dark box or a black curtain, accurate characteristic evaluation becomes difficult due to the influence of the external environment such as wind, light, and temperature during the test. However, those that do not affect the evaluation of the electrophotographic photosensitive drum, such as a controller and a signal processing circuit, do not need to be covered with a dark box or a black curtain.

The procedure for evaluating the characteristics of an electrophotographic photosensitive member using the electrophotographic photosensitive member characteristic evaluation apparatus of the present invention will be described below, taking the case where the number (n) of surface potential detecting means is three as an example. 2 will be described with reference to FIG.
First, a first measurement is performed using a surface potential detection unit (detection unit interval d = 8 mm) in which n (= 3) surface potential detection units are arranged in the axial direction of the charging unit, the neutralization unit, and the electrophotographic photosensitive drum. Immediately after this measurement, the charging potential (VD) for one rotation of the drum at three positions (range h) of the range (distances from the end A of the electrophotographic photosensitive member 1 are 162, 170, and 178 mm) is measured. In addition, the charging means, the static elimination means, and the surface potential detection means unit are moved toward the end B by a distance n-1 times the distance (8 mm) between the surface potential detection means [d × (n−1) = 8 × 2]. = 16 mm], and 10 seconds after the measurement at the 3 positions in [Range h], VD measurement is performed for one revolution of the drum at 3 positions (178, 186, 194 mm) in the range k.
Thereafter, it is determined whether or not the difference between the measurement results at the position 178 mm in the range h and the position 178 mm in the range k is less than ± 5V.

  If the determination result is less than ± 5 V, the charging means, the static elimination means, and the surface potential detection means unit are further moved 16 mm toward the end B, and 3 positions in the range l (the end of the electrophotographic photoreceptor 2) VD measurement is performed at a distance of 194, 202, and 210 mm from A), and similarly, a difference in measurement results between the position of 194 mm in the range l and the position of 194 mm in the range k is determined.

In the case of ± 5 V or more, this means that the charging means, the static elimination means, and the surface potential detection means unit are moved toward the end B by n + m times the distance between the two surface potential detection means [d × (n + m) = 8 × (3 + 1 ) = 32 mm] again, VD measurement is performed at 3 positions in the range j (the distances from the end A of the electrophotographic photoreceptor 2 are 210, 218, 226 mm), and the position 178 mm in the range h and the position j in the range j A linear function representing the relationship between the axial position and the charging potential is obtained from the measurement result at the position of 210 mm.
From the obtained linear function, VD at three positions in the range i (distances from the end A of the electrophotographic photoreceptor 2 are 186, 194, 202 mm) is calculated and interpolated.

Further, the charging unit, the neutralizing unit, and the surface potential detecting unit are moved toward the end portion B by a distance n−1 times as large as two intervals of the surface potential detecting unit [[d × (n−1) = 8 × 2 = 16 mm. The VD measurement is performed at three positions in the range m (distances from the end A of the electrophotographic photosensitive member 2 are 226, 234 and 242 mm), and the position 226 mm in the range j and the position 226 mm in the range m are measured. Determine the difference in measurement results.
Characteristic evaluation is performed by performing such an operation, and this is repeated from the end A to the end B of the electrophotographic photoreceptor to evaluate the characteristics in a predetermined region in the axial direction of the electrophotographic photoreceptor. I do.

  EXAMPLES The present invention will be specifically described below with reference to examples of the present invention, but the present invention is not limited to these examples.

  In the comparative examples and examples shown below, the characteristics of the electrophotographic photosensitive member were evaluated using an electrophotographic photosensitive member characteristic evaluation apparatus as shown in FIGS. In the electrophotographic photoreceptor characteristic evaluation apparatus, the charging means 6 is an in-house manufactured scorotron charger having a grid opening width of 60 mm in the axial direction and 15 mm in the circumferential direction, and a voltage is applied to the wire electrode of the scorotron charger. The high voltage power supply 7 to be applied was manufactured by TREK, and the power supply 12 for applying a voltage to the grid electrode of the scorotron charger was manufactured by Matsusada Precision Co., Ltd. The static elimination light source as the static elimination means 8 is a processed product of LED (wavelength: 660 nm) manufactured by Stanley Electric Co., Ltd., and the size in the axial direction is 70 mm. The surface potential meter unit 14 which is a surface potential detection means unit is composed of three surface potential meters manufactured by TREK, and the surface potential meter probe unit 13 which is a surface potential detection means unit has an equal interval of 8 mm pitch in the axial direction. Are composed of three surface potentiometer probes manufactured by TREK.

  The surface potential detecting means unit can simultaneously measure charging potentials at three positions in the axial direction of the electrophotographic photoreceptor. The motor 16 is manufactured by Oriental Motor Co., Ltd., the controller 17 is a sequencer manufactured by Keyence Corporation and a PC manufactured by Hitachi, the A / D converter 10 is an A / D converter manufactured by Keyence Corporation, and the digital relay output 23 is Keyence Corporation. It is made. For the other signal processing circuits, etc., an in-house electrophotographic photoreceptor characteristic evaluation apparatus was used.

  The used electrophotographic photoreceptors 1 and 2 (drum diameter 30 mm, drum total length 340 mm) have the same prescription as the photoreceptor mounted on Rigoh Co., Ltd. imgioMF7070. The effect of the previous measurement is likely to remain in the next measurement. In Test Example 1, Comparative Example 2, Example 2, and Example 3, the electrophotographic photoreceptor 1 in which the influence of the previous measurement is likely to remain in the next measurement when repeated measurement is performed is shown in Comparative Example 1. In Example 1, the electrophotographic photoreceptor 2 is used in which the influence of the previous measurement does not remain in the next measurement when repeated measurement is performed.

  The end on the front side of the evaluation device of the photoconductor is referred to as end A, and the end on the back side of the evaluation device is referred to as end B. Of the three surface electrometer probes, the central surface electrometer probe is disposed in the axial direction of the electrophotographic photosensitive member. The central position of the charging unit and the previous neutralizing unit is the position of the electrophotographic photosensitive member. Equal to the position arranged in the axial direction.

<Test Example 1>
After measuring the electrification potential (VD) for one rotation of the drum at a distance of 178 mm from the end A of the electrophotographic photoreceptor 1, leave it in the apparatus for 5 minutes to reduce the influence of the measurement, and then repeat the same. VD measurement for one rotation of the drum at the position was performed. The respective average values were calculated from the VD for one initial revolution of the drum at the position of 178 mm and the VD for one revolution of the drum, and the difference between the initial VD and the remeasurement VD was obtained. The results are shown in Table 1.

  Next, 10 seconds after measuring the charged potential (VD) for one revolution of the drum at a position where the distance from the end A of the electrophotographic photosensitive member is 178 mm, VD measurement for one revolution of the drum at the same position was performed again. The average values were calculated from the VD for one revolution of the drum at the initial measurement and the VD for one revolution of the drum at the position of 178 mm, and the difference between the initial measurement VD and the remeasurement VD was obtained. The results are shown in Table 1.

  As can be seen from Table 1, when the measurement time interval is 5 minutes, the initial measurement VD and the remeasurement VD are substantially equal, whereas when the measurement time interval is 10 seconds, the initial measurement VD and the remeasurement. There was a big difference in VD. From this result, when the measurement time interval is long in the measurement at the same position, the influence of the previous measurement on the next measurement is extremely small, and when the measurement time interval is short, the previous measurement has a large influence on the next measurement. You can see that

<Comparative Example 1>
The charging potential (VD) measurement for one rotation of the drum at three positions in the range a (distances from the end A of the electrophotographic photoreceptor 2 of 114, 122, and 130 mm) is simultaneously performed, and charging means, static elimination means, and surface potential are measured. The detection unit is moved 24 mm toward the end B, and after 5 minutes, VD measurement for one rotation of the drum at two positions in the range b (the distance from the end A of the electrophotographic photoreceptor 2 is 138, 146 mm). At the same time. By providing a sufficient measurement time interval of 5 minutes, the measurement before movement does not affect the measurement after movement. The influence ranges a and b indicate the following ranges as shown in FIG.
Range a: a range in which the distance from the end A of the electrophotographic photoreceptor 2 is 114 to 130 mm.
Range b: A range in which the distance from the end A of the electrophotographic photoreceptor 2 is 138 to 146 mm.
From the measurement results, the average value of the VD data for one rotation of the drum at each position was calculated. Table 2 and FIG. 4 show the results of calculating the difference between the VD at each position and the reference VD with the VD at the position of 130 mm as the reference VD.
-Measurement time interval: 10 seconds-
Subsequently, the same measurement as that in the previous measurement time interval: 5 minutes was performed at the measurement time interval: 10 seconds. This is a conventional potential distribution measurement method in the axial direction in which measurement is performed while moving at a measurement time interval of 10 seconds so that the measurement range after movement does not overlap the measurement range before movement.
From the measurement results, the average value of the VD data for one rotation of the drum at each position is calculated, and the result of calculating the difference between the VD at each position and the reference VD with the VD at the position of 130 mm as the reference VD is shown in Table 2. Shown in Moreover, it shows in Table 2, FIG. 4 together with the result of having calculated the difference with the result of measurement time interval 5 minutes.

  From Table 2, the value of “VD difference with respect to reference VD (measurement time interval: 5 minutes) −VD difference with respect to reference VD (measurement time interval: 10 seconds)” at two positions (138, 146 mm) in range b is small. 4, the measurement time interval of Comparative Example 1: 10 seconds (conventional measurement method) VD distribution is the measurement time interval of Comparative Example 1: 5 minutes (the measurement after movement is affected by the measurement before movement) Distribution characteristics similar to those of the VD distribution in the case where the measurement is not performed) and the measurement time interval of Comparative Example 1 is 10 seconds (conventional measurement method), the measurement after the movement (measurement of the range b) is the measurement before the movement. It can be seen that there is no influence of (measurement of range a).

<Example 1>
Immediately after measuring the charging potential (VD) for one rotation of the drum at three positions in the range a, the charging unit, the discharging unit, and the surface potential detecting unit are moved 16 mm toward the end B, and 10 seconds from the measurement of the range a. Later, VD measurement for one revolution of the drum in the range c was performed.
Thereafter, it was determined whether or not the difference in the measurement result between the position 130 mm in the range a and the position 130 mm in the range c was less than ± 5V. The value of less than ± 5.0 V is a small value that does not cause a large difference in the density of the output image in the image forming apparatus, and the measurement error in the post-movement VD measurement that occurs due to the VD measurement before the movement is extremely small. I can judge. On the contrary, the value of ± 5.0 V or more is such a large value that an obvious difference is generated in the density of the output image in the image forming apparatus, and the measurement error of the post-movement VD measurement generated by the VD measurement before the movement is large. It means big.

  If the determination result is less than ± 5 V, the charging unit, the neutralizing unit, and the surface potential detecting unit are moved again by 16 mm toward the end B, and the three positions in the range d (the end of the electrophotographic photoreceptor 2) VD measurement is performed at distances from A of 146, 154, and 162 mm), and similarly, a difference in measurement results between the position of 146 mm in the range c and the position of 146 mm in the range d is determined. In the case of ± 5 V or more, the charging means, the charge eliminating means, and the surface potential detecting means unit are moved again 32 mm toward the end B, and the three positions in the range e (the distance from the end A of the electrophotographic photoreceptor 2 is 162, 170, 178 mm), and a linear function representing the relationship between the position in the axial direction and the charged potential is obtained from the measurement result of the position 130 mm in the range a and the position 162 mm in the range e. From the next function, VD at three positions in the range f (the distances from the end A of the electrophotographic photosensitive member 2 are 138, 146, 154 mm) is calculated and interpolated, and further, charging means, static elimination means, surface potential detection means The unit is moved 16 mm toward the end B, and VD measurement is performed at 3 positions in the range g (distances from the end A of the electrophotographic photoreceptor 2 are 178, 186, 194 mm), and the position 178 mm in the range e And 1 in range g Determine the difference between the measurement results of the position of 8 mm. Characteristic evaluation was performed by such a method.

The ranges c, d, e, f, and g refer to the following ranges as illustrated in FIG.
-Range c: A range in which the distance from the end A of the electrophotographic photoreceptor 2 is 130 to 146 mm.
Range d: A range in which the distance from the end A of the electrophotographic photoreceptor 2 is 146 to 162 mm.
Range e: a range in which the distance from the end A of the electrophotographic photoreceptor 2 is 162 to 178 mm.
Range f: a range in which the distance from the end A of the electrophotographic photoreceptor 2 is 138 to 154 mm.
-Range g: A range in which the distance from the end A of the electrophotographic photoreceptor 2 is 178 to 194 mm.

  From the measurement results, the average value of the VD data for the three positions in the range a, the three positions in the range c, and one revolution of the drum at each position is calculated, and the VD at the 130 mm position in the range a is set as the reference VD. Table 3 shows the result of calculating the difference between each VD at the three positions and the reference VD, and Table 4 shows the result of calculating the difference between each VD at the three positions in the range c and the reference VD.

  As shown in Table 4, the difference between the VD at the position 130 mm in the range c and the reference VD is 2.4 V, and the difference in VD between the position 130 mm in the range a and the position 130 mm in the range c is ± 5.0 V. Less than and small. From this result, it is understood that when the measurement of the range c is performed immediately after the measurement of the range a, the measurement of the range a does not affect the measurement of the range c.

  Accordingly, it is determined that there is no measurement error in the VD measurement in the range c after the movement that occurs due to the VD measurement in the range a before the movement, and the axial VD distribution of the electrophotographic photoreceptor 2 is created using the measurement result. did. When creating the potential distribution, the measurement result before movement (result of range a) was used as the VD value at the same position. The created VD distribution is shown in FIG. The VD distribution of Example 1 (measurement method of the present invention) is a distribution characteristic close to the VD distribution of the measurement time interval of Comparative Example 1: 5 minutes (when measurement after movement is not affected by measurement before movement). The measurement time interval of Comparative Example 1 is 10 seconds (conventional measurement method), and it can be seen that the measurement after the movement can be performed without being affected by the measurement before the movement. .

  When the voltage is less than ± 5.0 V, VD measurement is performed at three positions in the range d, and the difference between the measurement results at the position 146 mm in the range c and the position 146 mm in the range d is similarly determined. The implementation method is the same as the determination of the difference between the measurement results of 130 mm in the range a and 130 mm in the range c. The determination result is less than ± 5.0 V, and the measurement after the movement can be performed without being affected by the measurement before the movement.

<Comparative example 2>
-Measurement time interval: 5 minutes-
The charging potential (VD) measurement for one rotation of the drum at three positions in the range h (distance from the end A of the electrophotographic photosensitive member 1 is 162, 170, 178 mm) is simultaneously performed, and charging means, static elimination means, and surface potential are measured. The detection means unit is moved 24 mm toward the end B, and 5 minutes later, one round of the drum at three positions in the range i (distances from the end A of the electrophotographic photoreceptor 1 are 186, 194, 202 mm) VD measurement at the same time, and further, the charging means, the static elimination means, and the surface potential detection means unit are moved 24 mm toward the end B, and after 5 minutes, three positions in the range j (the end of the electrophotographic photoreceptor 1) VD measurement was performed simultaneously for one revolution of the drum whose distance from A was 210, 218, 226 mm. By providing a sufficient measurement time interval of 5 minutes, the measurement before movement does not affect the measurement after movement.

The ranges h, i, and j refer to the following ranges as illustrated in FIG.
Range h: A range in which the distance from the end A of the electrophotographic photoreceptor 1 is 162 to 178 mm.
Range i: A range in which the distance from the end A of the electrophotographic photoreceptor 1 is 186 to 202 mm.
Range j: A range in which the distance from the end A of the electrophotographic photoreceptor 1 is 210 to 226 mm.
From the measurement results, the average value of the VD data for one rotation of the drum at each position was calculated. Table 5 and FIG. 6 show the results of calculating the difference between the VD at each position and the reference VD with the VD at the position of 178 mm as the reference VD.

-Measurement time interval: 10 seconds-
Subsequently, the same measurement as the measurement time interval of the previous period: 5 minutes was performed at the measurement interval: 10 seconds. This is a conventional potential distribution measurement method in the axial direction in which measurement is performed while moving at a measurement time interval of 10 seconds so that the measurement range after movement does not overlap the measurement range before movement.
From the measurement results, the average value of the VD data for one rotation of the drum at each position was calculated, and the result of calculating the difference between the VD at each position and the reference VD with the VD at the position of 178 mm as the reference VD is shown in Table 1. Shown in Moreover, it shows in Table 5, FIG. 6 together with the result of having calculated the difference with the result of measurement time interval 5 minutes.

  From Table 5, the value of “VD difference with respect to reference VD (measurement time interval: 5 minutes) −VD difference with respect to reference VD (measurement time interval: 10 seconds)” at a position of 186 mm and a position of 210 mm from end A 6, the measurement time interval of Comparative Example 2 is 10 seconds (conventional measurement method), and the VD distribution is 5 minutes (Comparison example 2 is the measurement time before the measurement) The distribution characteristics differ from the VD distribution in the case of not being influenced by the measurement), and the measurement time interval of Comparative Example 2 is 10 seconds (conventional measurement method). You can see that

<Example 2>
Immediately after the charge potential (VD) measurement for one circumference of the drum at three positions in the range h (distances from the end A of the electrophotographic photoreceptor 1 of 162, 170, 178 mm), the charging means, the static elimination means, and the surface potential The detection unit is moved 16 mm toward the end B, and after 10 seconds from the measurement of the three positions in the range h, the three positions in the range k (the distance from the end A of the electrophotographic photoreceptor 1 is 178, 186, 194 mm) VD was measured for one round of the drum.

Thereafter, it was determined whether or not the difference between the measurement results at the position 178 mm in the range h and the position 178 mm in the range k was less than ± 5V.
The result of calculating the difference between each VD in the range h and the reference VD is shown in Table 6, and the result of calculating the difference between each VD in the range k and the reference VD is shown as VD at the position 178 mm in the range h as the reference VD. 7 shows.

  As shown in Table 7, when the VD measurement in the range k is performed immediately after the charging potential (VD) measurement in the range h, the difference between the VD at the position of 178 mm in the range k and the reference VD is −9. 7 V, and a large difference of ± 5.0 V or more occurred in VD at the position 178 mm in the range h and the position 178 mm in the range k. From this result, it is understood that when the measurement of the range k is performed immediately after the measurement of the range h, the measurement of the range k is greatly affected by the measurement of the range h.

  Therefore, the charging unit, the neutralizing unit, and the surface potential detecting unit are moved from the range k by a distance of 32 mm toward the end B, and the range 3 (range j) that is not affected by the measurement of the ranges h and k. VD measurement was performed for one rotation of the drum at two positions (distances from the end A of the electrophotographic photoreceptor 1 are 210, 218, and 226 mm). Table 8 shows the result of calculating the difference between each VD in the range j and the reference VD, with the VD at the position of 178 mm in the range h as the reference VD. From the remeasured VD at the position closest to the end B of the range h (position of 178 mm) and the VD at the position closest to the end A of the range j (position of 210 mm), three positions in the range i (electronic The VD having a distance from the end A of the photographic photoreceptor 1 of 186, 194, 202 mm) is interpolated. The interpolation method is based on the value of VD at the position closest to the end B of the range h and the value of VD at the position closest to the end A of the range j, and the measured position (distance from the end A) and VD. A linear function representing the relationship is obtained, and VDs at three positions 186, 194, and 202 mm in the range i are calculated from the obtained linear function. FIG. 7 shows the obtained linear function, and Table 9 shows VDs at three positions of 186, 194, and 202 mm calculated from the linear function.

  FIG. 6 shows the axial VD distribution of the electrophotographic photoreceptor 1 created from the measurement results of the range h and the range j and the interpolation result of the range i. In the measurement time interval of Comparative Example 2: 10 seconds (conventional measurement method), the measurement after the movement is affected by the measurement before the movement, and the measurement time interval of the Comparative Example 2 is a VD distribution of 5 minutes. The distribution characteristics are different from those in the case where the measurement after the movement is not affected by the measurement before the movement. On the other hand, the VD distribution of Example 2 (the measurement method of the present invention) is similar to the VD distribution of the measurement time interval of Comparative Example 2: 5 minutes (when the measurement after movement is not affected by the measurement before movement). Thus, it can be seen that the measurement after the movement can be performed without being affected by the measurement before the movement.

After interpolating the VD at the three positions in the range i, the VD measurement at the three positions in the range m is performed to determine the difference in the measurement results between the position 226 mm in the range j and the position 226 mm in the range m. This is the same as the determination of the difference between the measurement result of 178 mm in the range h and the measurement result of 178 mm in the range k. The determination result is less than ± 5.0 V, and the measurement after the movement can be performed without being affected by the measurement before the movement.
The ranges k, l, and m refer to the following ranges as illustrated in FIG.
Range k: a range in which the distance from the end A of the electrophotographic photoreceptor 1 is 178 to 194 mm.
Range l: A range in which the distance from the end A of the electrophotographic photoreceptor 1 is 194 to 210 mm.
Range m: a range in which the distance from the end A of the electrophotographic photoreceptor 1 is 226 to 242 mm.

<Example 3>
In the region of 90 mm to 250 mm from the end A of the electrophotographic photoreceptor 1, the characteristics were evaluated in the same manner as in Example 2. In Example 3, the measurement time interval of Comparative Example 2 is the same as the measurement time interval of 10 minutes (the conventional measurement method), and the measurement time interval of Comparative Example 2 is 5 minutes. A distribution characteristic similar to that obtained by the characteristic evaluation in the case where the measurement after the movement is not affected by the measurement before the movement) was obtained. Therefore, even in the region of 90 mm to 250 mm from the end A of the electrophotographic photoreceptor 1, the measurement after the movement can be performed without being affected by the measurement before the movement, as in the first and second embodiments. I was able to confirm.

DESCRIPTION OF SYMBOLS 1 Electrophotographic photosensitive drum 2 Exposure means 3 Surface potential meter probe unit 4 Surface potential meter unit 5 Signal processing circuit 6 Charging means 7 High voltage power supply 8 Static elimination means 9 Signal processing circuit 10 AD converter 11 Rotary encoder 12 Power supply 13 Surface potential Meter probe unit 14 Surface potential meter unit 15 Power switch 16 Motor 17 Controller 18 Spindle 19 Belt 20 Drum chuck jig 21 Face plate 22 on the front side (one end side of the electrophotographic photosensitive drum) Back side (electrophotographic photosensitive drum) The other side of the face plate 23 Digital (relay) output

Japanese Patent Laid-Open No. 4-26852

Claims (4)

A charging means, a discharging means, and a surface potential detecting unit in which n surface potential detecting means are arranged in the axial direction of the electrophotographic photosensitive drum (n is an integer, n ≧ 2); When measuring the charging potential distribution in the axial direction, the charging potentials at any n locations in the axial direction are simultaneously measured, and then from one end A of the electrophotographic photosensitive drum to the other end B. Then, the charging means, the charge eliminating means, and the surface potential detection unit are moved by a distance n-1 times the interval between the two surface potential detection means, and the n charged potentials are simultaneously measured, and the end after the movement The difference between the detection results of the surface potential detection means closer to A and the surface potential detection means closer to the end B before the movement is calculated, and it is determined whether or not it is within a predetermined range. A device for evaluating characteristics of a photoreceptor,
When the difference between the detection results of the surface potential detection means closer to the end A after the movement and the surface potential detection means closer to the end B before the movement is within a predetermined range, The charging means, the charge eliminating means, and the surface potential detecting unit are moved toward the end B in the direction by a distance that is n-1 times the two intervals of the surface potential detecting means, so that n charged potentials are simultaneously measured. Then, the detection result is discriminated by the same discrimination method, and if the difference in the detection result is out of the predetermined range, the one end A of the electrophotographic photosensitive drum is connected to the other end. Moving toward the portion B, the charging means, the static elimination means, and the surface potential detection unit are moved again by a distance of n + m times (m is an integer, m ≧ 1) the interval between the two surface potential detection means, Simultaneously measure the charging potential, the surface potential before the movement From the detection result of the output means and the detection result of the surface potential detection means after re-moving, the charge potential value of the unmeasured area in the axial direction is calculated and interpolated, and further the surface potential is detected toward the end B in the axial direction The charging means, the static elimination means, and the surface potential detection unit are moved by a distance n-1 times the two intervals of the means, and the n charged potentials are simultaneously measured, and the detection results are discriminated by the same discrimination method. An apparatus for evaluating characteristics of an electrophotographic photoreceptor, characterized in that it is provided . Interpolation of the value of the charged potential in the unmeasured area in the axial direction is performed by detecting the surface potential detection means closer to the end B before the movement and the surface potential closer to the end A after the re-movement. A linear function representing the relationship between the axial position and the charging potential is obtained from the detection result of the detecting means, and the charging potential value of the unmeasured area in the axial direction is calculated from the obtained linear function. The apparatus for evaluating characteristics of an electrophotographic photosensitive member according to claim 1 . The operation for discriminating the detection result is repeatedly performed from the end A to the end B of the electrophotographic photoreceptor, and the characteristic evaluation in a predetermined region in the axial direction of the electrophotographic photoreceptor is performed. The apparatus for evaluating characteristics of an electrophotographic photoreceptor according to claim 1 or 2 . Characterization methods of the electrophotographic photoreceptor and evaluating the characteristics of the electrophotographic photosensitive member using the characteristic evaluation apparatus according to any one of claims 1-3.

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