Electrophotographic apparatus

Abstract

The present invention relates to an electrophotographic apparatus. Provided is an electrophotographic apparatus including: an electrophotographic photosensitive member; a voltage application unit configured to cause discharge from a conductive member to the electrophotographic photosensitive member; a charge movement amount detection unit configured to detect a charge movement amount per unit time caused by the discharge from the conductive member to the electrophotographic photosensitive member; and a charging potential control unit, wherein, for the electrophotographic photosensitive member, V1 and V2 determined by a specific process satisfy a relationship represented by the following expression (E-4): 100 < V2 - V1 (E-4), and wherein the charging potential control unit is configured to control a charging potential of the electrophotographic photosensitive member at the time of image formation.

Description

Technical Field

[0001] This invention relates to electronic photographic equipment. Background Technology

[0002] In electrophotographic devices that use electrophotographic photosensitive components, such as copiers, laser beam printers, or fax machines, the electrophotographic photosensitive component is first uniformly charged, and an electrostatic latent image is formed on the electrophotographic photosensitive component using an image exposure unit such as a laser scanner. Then, the electrostatic latent image is developed with a toner to form a toner image on the electrophotographic photosensitive component. Further, the toner image is transferred from the electrophotographic photosensitive component to a transfer material such as paper, and the transferred toner image is fixed using heat or pressure. Thus, image formation is achieved.

[0003] In recent years, electrophotographic equipment has been required to precisely control the charging potential of the electrophotographic photosensitive element during image formation to a desired value, so as to output an image with constant density regardless of the operating environment of the electrophotographic equipment and changes in states such as the thickness of the photosensitive element layer.

[0004] In addition, along with the foregoing, it is also required to shorten the calibration time (referred to as "downtime") when performing the above-mentioned controls without image formation, and it is also strongly required to perform this control at a high speed.

[0005] As a prior art for controlling the charged potential of an electrophotographic photosensitive component to a desired value during image formation, a technique involving directly detecting the charged potential of the electrophotographic photosensitive component using a potentiometer installed in an electrophotographic device has been proposed (Japanese Patent Application Publication No. H05-66638).

[0006] Furthermore, as a technique that does not use a potentiometer, a method has been proposed that involves estimating the voltage at which discharge begins between the charging member and the electrophotographic photosensitive member (referred to as the "discharge start voltage"), thereby optimizing the charged potential of the electrophotographic photosensitive member during image formation with high precision (Japanese Patent No. 5615004). For example, when the electrophotographic photosensitive member is charged by means of a charging roller used as a charging member, a high voltage is applied to the charging roller by a charging unit. Then, while detecting the discharge current flowing through the charging roller, the voltage to be applied is gradually changed, and the discharge start voltage is estimated based on the applied voltage and the value of the detected discharge current.

[0007] However, the problem with the charged potential measurement method described in Japanese Patent Application Publication No. H05-66638 is that when space is secured within the device for setting up a potentiometer to accurately control the charged potential to the desired value, the size of the electrophotographic device increases and it becomes expensive.

[0008] Furthermore, in the method described in Japanese Patent No. 5615004, the absolute value of the voltage needs to be gradually increased from the voltage at which discharge from the charging roller to the electrophotographic photosensitive element does not occur. As a result, although it has high accuracy, the problem with this method is that it requires time to complete the control. Therefore, it is difficult to control the charged potential with high accuracy in a short time, and in recent years, when further reductions in downtime are required, the effect obtained by the method described in Japanese Patent No. 5615004 is not sufficient. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide an electrophotographic device that can control the charged potential of an electrophotographic photosensitive component during image formation with high precision in a short time.

[0010] The above objectives are achieved through the invention described below.

[0011] That is, the electrophotographic device according to the present invention is an electrophotographic device comprising: an electrophotographic photosensitive element; a voltage application unit configured to cause discharge from a conductive element to the electrophotographic photosensitive element; a charge transfer amount detection unit configured to detect the amount of charge transfer per unit time caused by the discharge from the conductive element to the electrophotographic photosensitive element; and a charge potential control unit configured to control the charge potential of the electrophotographic photosensitive element, wherein when V1 and V2 are determined for the electrophotographic photosensitive element by the following processes (1) to (8), V1 and V2 satisfy the relationship expressed by the following formula (E-4):

[0012] 100V1 <V2-V1(E-4),

[0013] Furthermore, the charge potential control unit is configured to control the charge potential of the electrophotographic photosensitive element during image formation by means of the relationship between the DC voltage at at least two points selected from those in the range where the absolute value of the DC voltage applied by the voltage application unit is 700V or more, and the amount of charge movement at the DC voltage at said at least two points.

[0014] (1) Charge the electrophotographic photosensitive component for 0.005 seconds;

[0015] (2) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (1) is V d [V] indicates;

[0016] (3) After charging begins in (1) for 0.18 seconds, charge the electrophotographic photosensitive element for 0.005 seconds so that the absolute value of the charged potential becomes V again. d;

[0017] (4) 0.02 seconds after the start of charging in (3), use light with a wavelength of 805 nm and a light intensity of 0.5 μJ / cm. 2 Expose the light;

[0018] (5) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (3) is defined as the residual potential V. r [V];

[0019] (6) When making V d While varying the voltage from 100V to 1,000V in 50V increments, processes (1) to (5) are repeated to measure the voltage corresponding to V. d V values r ;

[0020] (7) The V obtained by plotting in (6) d and V r The obtained graph is approximated by the following equation (E-1) to determine the constants A, "m", and τ in the following equation (E-1), where the horizontal axis represents V. d And the vertical axis represents V r ,

[0021] and

[0022] (8) The voltages calculated by using the constants A, "m" and τ determined in (7) through the following equations (E-2) and (E-3) are defined as V1 and V2, respectively:

[0023]

[0024] In equation (E-2), V min This represents the value determined by the accuracy of the charge movement detection unit.

[0025]

[0026] Further features of the invention will become apparent from the following description of exemplary embodiments, with reference to the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a diagram illustrating an example of the layer structure of the electrophotographic photosensitive component to be used in the present invention.

[0028] Figure 2 To show the absolute value V of the charged potential d With residual potential V r A diagram showing the relationships between them.

[0029] Figure 3To show the absolute value V of the charged potential d and V d With residual potential V r A graph showing the relationship between the difference ΔV.

[0030] Figure 4 The figure is for illustrating an example of a schematic configuration of an electrophotographic device according to the present invention, wherein the electrophotographic device includes a processing box having an electrophotographic photosensitive element and its voltage application unit is a charging unit.

[0031] Figure 5 This diagram is used to schematically illustrate the evaluation device used for evaluation in the embodiments. Detailed Implementation

[0032] The present invention is described in detail below by way of exemplary embodiments.

[0033] [Electronic photographic equipment]

[0034] The electrophotographic apparatus according to the present invention comprises: an electrophotographic photosensitive element; a voltage application unit configured to cause discharge from a conductive element to the electrophotographic photosensitive element; a charge movement detection unit configured to detect the amount of charge movement per unit time caused by the discharge from the conductive element to the electrophotographic photosensitive element; and a charge potential control unit configured to control the charge potential of the electrophotographic photosensitive element, wherein when V1 and V2 are determined for the electrophotographic photosensitive element by the following processes (1) to (8), V1 and V2 satisfy the relationship expressed by the following formula (E-4):

[0035] 100V1 <V2-V1(E-4)

[0036] Furthermore, the charge potential control unit is configured to control the charge potential of the electrophotographic photosensitive element during image formation by means of the relationship between the DC voltage at at least two points selected from those in the range where the absolute value of the DC voltage applied by the voltage application unit is 700V or more, and the amount of charge movement at the DC voltage at said at least two points.

[0037] (1) Charge the electrophotographic photosensitive component for 0.005 seconds;

[0038] (2) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (1) is V d [V] indicates;

[0039] (3) After charging begins in (1) for 0.18 seconds, charge the electrophotographic photosensitive element for 0.005 seconds so that the absolute value of the charged potential becomes V again. d ;

[0040] (4) 0.02 seconds after the start of charging in (3), use light with a wavelength of 805 nm and a light intensity of 0.5 μJ / cm. 2 Expose the light;

[0041] (5) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (3) is defined as the residual potential V. r [V];

[0042] (6) When making V d While varying the voltage from 100V to 1,000V in 50V increments, processes (1) to (5) are repeated to measure the voltage corresponding to V. d V values r ;

[0043] (7) The V obtained by plotting in (6) d and V r The obtained graph is approximated by the following equation (E-1) to determine the constants A, "m", and τ in the following equation (E-1), where the horizontal axis represents V. d And the vertical axis represents V r ,

[0044] and

[0045] (8) The voltages calculated by using the constants A, "m" and τ determined in (7) through the following equations (E-2) and (E-3) are defined as V1 and V2, respectively:

[0046]

[0047] In equation (E-2), V min This represents the value determined by the accuracy of the charge movement detection unit.

[0048]

[0049] Typically, when an electrophotographic photosensitive element is charged and exposed during actual image formation, its electrical potential does not necessarily become zero. The potential at the exposed portion, especially under high exposure conditions, is specifically referred to as the residual potential.

[0050] In this invention, the residual potential V r Determined through the following process:

[0051] (1) Charge the electrophotographic photosensitive component for 0.005 seconds;

[0052] (2) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (1) is V d [V] indicates;

[0053] (3) After charging begins in (1) for 0.18 seconds, charge the electrophotographic photosensitive element for 0.005 seconds so that the absolute value of the charged potential becomes V again. d ;

[0054] (4) 0.02 seconds after the start of charging in (3), use light with a wavelength of 805 nm and a light intensity of 0.5 μJ / cm. 2 Expose the light; and

[0055] (5) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (3) is defined as the residual potential V. r [V].

[0056] The inventors applied V at 50V intervals. d While varying the voltage from 100V to 1,000V, the V values ​​were studied according to the processes described in (1) to (5) above. d With residual potential V r The relationship between the two was found to be approximated by the following equation (E-1).

[0057]

[0058] In the formula, the constant A corresponds to the value of V. d The residual potential V when =0 is substituted into equation (E-1) r And it means that when drawing such a thing... Figure 2 The diagram shown (where the horizontal axis represents V) d And the vertical axis represents V r When ), the intercept of the approximate function represented by equation (E-1) at the intersection with the vertical axis.

[0059] Furthermore, the constant "m" refers to the connection of V in the approximate function represented by equation (E-1). d =0 and V d The slope of the line between two points = 1,000.

[0060] Furthermore, the constant τ represents the linearity of the approximate function represented by equation (E-1), and in particular, in the limit of τ→±∞, the approximate function represented by equation (E-1) becomes a straight line.

[0061] Furthermore, the inventors attempted to analyze various electrophotographic photosensitive components using the aforementioned approximation function, and found that the values ​​of the constants A, "m", and τ in equation (E-1) vary depending on the configuration of the electrophotographic photosensitive component.

[0062] Furthermore, the inventors have discovered that when the charged potential of the electrophotographic photosensitive component during image formation is controlled by the charged potential control unit described later, the conditions for achieving both high precision and short time can be calculated based on the values ​​of these constants.

[0063] The above conditions are described in detail below.

[0064] In this invention, the following configuration is used: detecting the amount of charge movement per unit time caused by discharge instead of detecting the charged potential of the electrophotographic photosensitive element. The amount of charge movement I per unit time caused by discharge to the electrophotographic photosensitive element is related to the V of the electrophotographic photosensitive element. d With residual potential V r The difference is proportional and can be expressed by the following formula (E-5).

[0065] I = k(V) d -V r )=kΔV(E-5)

[0066] In equation (E-5), "k" represents a constant determined by factors such as the capacity of the electrophotographic photosensitive element.

[0067] Furthermore, in equation (E-5), ΔV can be expressed by equation (E-6) using the relationship in equation (E-1).

[0068]

[0069] As described later, the charge movement detection unit has the minimum detectable potential difference inherent in electrophotographic equipment. When the absolute value of the minimum detectable potential difference is V... min When indicated, in the V of the electrophotographic photosensitive element d With residual potential V r The difference is exactly equal to V min In the case of V1, the absolute value of the charge potential is the absolute value of the minimum detectable charge potential. When the absolute value of the minimum detectable charge potential is represented by V1, the following equation (E-7) can be derived from equation (E-6).

[0070]

[0071] V1 is the lower limit of the absolute value of the charged potential calculated based on the lower limit of the detectable charge movement in the body of the electrophotographic device. When equation (E-7) is solved for V1, equation (E-2) is obtained.

[0072]

[0073] Furthermore, the relationship expressed by equation (E-6) is represented by V on the horizontal axis. d And the vertical axis represents ΔV, as shown in the diagram. Figure 3The diagram shown illustrates this. As is evident from equation (E-6), such... Figure 3 The slope of the graph shown is not necessarily constant, and it varies with V. d As the slope increases, the gradient also changes. Consequently, when at high V... d When the discharge initiation voltage is estimated in the region as described in the prior art, a deviation Δ occurs relative to the actual discharge initiation voltage. A smaller absolute value of the deviation Δ indicates higher detection accuracy. Therefore, the absolute value of the charged potential when the absolute value of the deviation Δ reaches a predetermined value is represented by V2, and the upper limit condition for high-precision charged potential control is defined by V2. That is, V2 is the upper limit condition for the absolute value of the charged potential calculated based on the characteristics of the electrophotographic photosensitive component to obtain the desired accuracy.

[0074] The following describes how to calculate V2. First, when applying equation (E-6) to V... d When taking the differential, we obtain the following equation (E-8).

[0075]

[0076] The value obtained by formula (E-8) means Figure 3 The slope of the tangent at any point in the diagram shown, and therefore at V d The equation of the tangent at V2 is given by the following formula (E-9).

[0077]

[0078] Therefore, the intercept of the tangent to the horizontal axis represented by equation (E-9) is represented by the following equation (E-10) assuming ΔV = 0.

[0079]

[0080] When equation (E-10) is applied to V d Solve and assume V d When =Δ, we obtain the following equation (E-11).

[0081]

[0082] In typical electrophotographic equipment, to achieve high-precision control of the charged potential, the absolute value of the deviation Δ needs to be below 30V. When τ is positive, such as... Figure 2 As shown, V d With V r The relationship between them becomes a lower convex function, therefore, as Figure 3 As shown, V dThe relationship with ΔV becomes an upwardly convex function. Therefore, the intercept of the tangent line expressed by equation (E-9) with the horizontal axis takes a negative value. That is, when τ is positive, V2 is obtained by substituting Δ=-30 into equation (E-11) and solving equation (E-11) with respect to V2, and it can be expressed by the following equation (E-3-a) (V2>0).

[0083]

[0084] At the same time, when τ is negative, V d The relationship with ΔV becomes a convex function. Therefore, the intercept of the tangent line expressed by equation (E-9) with the horizontal axis takes a positive value. That is, when τ is negative, V2 is obtained by substituting Δ=30 into equation (E-11) and solving equation (E-11) with respect to V2, and it can be expressed by the following equation (E-3-b) (V2>0).

[0085]

[0086] Based on the above, V2 is divided into the following cases according to the sign of τ, so as to obtain the following formula (E-3).

[0087]

[0088] Next, the relationship between V1 and V2 described above will be described. Compared to the detection lower limit V1 of the charge movement detection unit in this invention, V1 is defined by V1 and V2. d The range needs to be set wide enough. As a result of research conducted by the inventors, it was found that the following condition (E-4) needs to be satisfied. That is, when controlling the charged potential of the electrophotographic photosensitive component during image formation, the condition for achieving both high precision and short time is to satisfy the following formula (E-4).

[0089] 100V1 <V2-V1(E-4)

[0090] As described above, the phenomenon that the residual potential of an electrophotographic photosensitive element changes with the increase of the charged potential is the cause of the deviation Δ relative to the actual discharge start voltage when estimating the discharge start voltage by detecting the amount of charge movement per unit time caused by the discharge. Therefore, as another technique to keep the deviation Δ at a low level, the charged potential can be controlled with high precision by providing a sufficiently long exposure time to bring the residual potential close to 0. However, when using this technique, a long control time is required to bring the residual potential to 0, resulting in an increase in downtime, and therefore it is impossible to achieve both high precision and short control time simultaneously.

[0091] In this invention, in order to control the charged potential with higher precision, the deviation Δ is preferably within 10V. In this case, in the same manner as in the above case, when Δ = -10 or Δ = 10 is substituted into equation (E-11), V2′ expressed by the following equation (E-12) is obtained.

[0092]

[0093] Therefore, V2′ and V1, as expressed by equation (E-2), preferably satisfy the relationship expressed by equation (E-13) to control the charged potential of the electrophotographic photosensitive component during image formation with higher precision.

[0094] 100V1 <V2′-V1 (E-13)

[0095] In this invention, as a characteristic of the electrophotographic photosensitive element, the absolute value of the residual potential is preferably low regardless of the charged potential. This is because the lower limit condition expressed by equation (E-2) can be made smaller and the upper limit condition expressed by equation (E-3) can be made larger. In particular, the absolute value of the constant A is preferably small, and specifically, the constant A is preferably 15 or less.

[0096] Furthermore, in this invention, as a characteristic of the electrophotographic photosensitive element, the slope of the change in residual potential relative to the charged potential is preferably small. That is, the constant "m" is preferably small, because the lower limit condition expressed by equation (E-2) can be smaller and the upper limit condition expressed by equation (E-3) can be larger. Specifically, the constant "m" is preferably 0.05 or less.

[0097] Furthermore, in this invention, the absolute value of the constant τ, which represents the characteristics of the electrophotographic photosensitive element, is preferably large. This is because it allows for a smaller lower limit condition expressed by equation (E-2) and a larger upper limit condition expressed by equation (E-3). Specifically, the absolute value of the constant τ is preferably 4,000 or more.

[0098] The voltage application unit in this invention can be a charging unit configured to charge the electrophotographic photosensitive element, a transfer unit configured to transfer toner from the surface of the electrophotographic photosensitive element to a transfer material, or it can be provided separately from the charging unit and the transfer unit. Furthermore, the conductive component in this invention can be a charging component configured to charge the electrophotographic photosensitive element, a transfer component, or it can be provided separately from these components.

[0099] In particular, it is preferred that the voltage application unit is a charging unit configured to charge the electrophotographic photosensitive member, and that the conductive member is a charging member. Furthermore, it is preferred that the voltage application unit is a transfer unit configured to transfer toner from the surface of the electrophotographic photosensitive member to a transfer material, and that the conductive member is a transfer member.

[0100] Furthermore, when the voltage application unit is a charging unit configured to charge the electrophotographic photosensitive element and the conductive element is a charging element, the charging element is preferably a charging roller.

[0101] Furthermore, when the voltage application unit is configured to transfer toner from the surface of an electrophotographic photosensitive component to a transfer material and the conductive component is a transfer component, the transfer component is preferably a transfer roller.

[0102] In addition to the aforementioned components, the electrophotographic apparatus according to the present invention may include, for example, an image exposure unit, a developing unit, a fixing unit, and a cleaning unit. The image exposure unit is configured to irradiate the surface of an electrophotographic photosensitive member with image exposure light to form an electrostatic latent image on the surface of the electrophotographic photosensitive member. Furthermore, the developing unit is configured to develop the electrostatic latent image with a toner to form a toner image on the surface of the electrophotographic photosensitive member. Furthermore, the fixing unit is configured to perform a process on a transfer material on which a toner image has been transferred by a transfer unit to fix the toner image. Furthermore, the cleaning unit is configured to remove residues such as toner adhering to the surface of the electrophotographic photosensitive member after transfer.

[0103] exist Figure 4 The illustration shows an example of an electrophotographic apparatus according to the present invention in which the voltage application unit is a charging unit and the conductive member is a charging member.

[0104] The cylindrical electrophotographic photosensitive element 1 is driven to rotate around axis 2 at a predetermined circumferential speed in the direction indicated by the arrow. The surface of the electrophotographic photosensitive element 1 is charged to a predetermined positive or negative potential by discharge via the charging member 3 through the charging unit 13. The charged surface of the electrophotographic photosensitive element 1 is irradiated with exposure light 4 from the exposure unit (not shown), thereby forming an electrostatic latent image corresponding to the target image information thereon. The electrostatic latent image formed on the surface of the electrophotographic photosensitive element 1 is developed with toner contained in the developing unit 5 to form a toner image on the surface of the electrophotographic photosensitive element 1. The toner image formed on the surface of the electrophotographic photosensitive element 1 is transferred to the transfer material 7 by means of the transfer member 6 mounted to the transfer unit 16. The transfer material 7, on which the toner image is transferred, is conveyed to the fixing unit 8, where the toner image is fixed and printed to the outside of the electrophotographic device.

[0105] Electrophotographic equipment may include a cleaning unit 9 configured to remove residues such as toners remaining on the surface of the electrophotographic photosensitive element 1 after transfer. Alternatively, a so-called "cleanerless" system may be used, configured to remove residues using a developing unit 5 or similar equipment without the need for a separate cleaning unit 9.

[0106] The electrophotographic device may include a static removal mechanism configured to perform static removal treatment on the surface of the electrophotographic photosensitive member 1 using pre-exposure light 10 from a pre-exposure unit (not shown). Furthermore, a guide unit 12, such as a guide rail, may be provided for detachably mounting the processing cartridge 11 to the main body of the electrophotographic device.

[0107] In the case where the charging unit 13 is a voltage application unit and the conductive member is the charging member 3, the electrophotographic device further includes a charge movement detection unit 14.

[0108] The charge movement detection unit 14 is configured to detect the amount of charge movement per unit time caused by the discharge from the charging member 3 to the electrophotographic photosensitive member 1. The detection section of the charge movement detection unit 14 includes: a detection circuit configured to convert the amount of charge movement flowing between the charging member 3 and the electrophotographic photosensitive member 1 when a DC voltage is applied into a voltage; and an amplifier configured to amplify the converted voltage signal and output the resulting signal as a discharge detection signal to the CPU. The CPU performs A / D conversion on the discharge detection signal from the amplifier using an A / D converter. Based on the A / D conversion output from the amplifier, the CPU identifies the magnitude of the generated current (the magnitude of the current flowing between the charging member and the electrophotographic photosensitive member) and can output an average current value over the time T (ms) of one rotation of the electrophotographic photosensitive member 1.

[0109] exist Figure 2 In this method, the amount of charge moving towards the charging member side when a voltage is applied is detected. However, the amount of charge moving towards the electrophotographic photosensitive member 1 when a voltage is applied can also be detected.

[0110] Furthermore, the charge movement detection unit 14 possesses a minimum detectable potential difference inherent in electrophotographic devices. This minimum detectable potential difference can be calculated as follows: When the charge movement per unit time is low due to electrical noise caused by the AC component, temperature variations in circuit resistance, or uneven rotation of the electrophotographic photosensitive element 1 or the charging element 3, the charge movement detection unit 14 cannot detect the charge movement caused by discharge from the charging element 3 to the electrophotographic photosensitive element 1. Therefore, there exists a minimum detectable charge movement I per unit time. min For measurement I min There are no particular restrictions on the method, but I can be measured, for example, in the following manner. minFirst, a DC voltage (e.g., -1,100V) is applied to the electrophotographic photosensitive element 1 during image formation. Then, under both a high-temperature, high-humidity environment of 32.5°C and 80% humidity and a low-temperature, low-humidity environment of 15°C and 10% humidity, the amount of charge movement per unit time during the driving of the drum motor is sampled by rotating the electrophotographic photosensitive element 1 10 times. Subsequently, the difference between the maximum and minimum values ​​of the charge movement per unit time can be used as the minimum detectable charge movement I per unit time. min .

[0111] In addition, I can min Convert to the minimum detectable potential difference. There are no particular limitations on the method, but methods such as those described below are available. First, (1) solve for Q = CV based on the rotational speed "v" of the electrophotographic photosensitive element 1, the thickness "d" of the charge transport layer of the electrophotographic photosensitive element 1, and the dielectric constant ε of the electrophotographic photosensitive element 1. In the formula, Q represents the charge, C represents the capacitance, and V represents the charge potential. Then, (2) apply a charging voltage V that takes into account that the temperature, humidity, and air pressure will necessarily exceed the discharge start voltage. a and V b And measure the amount of charge movement I per unit time during application. a and I b Then V is calculated using the following formula (E-14). min .

[0112] V min =|I min ×(V a -V b ) / (I a -I b (E-14)

[0113] In this invention, the electrophotographic device includes a charge potential control unit 15. The charge potential control unit 15 is configured to control the charge potential of the electrophotographic photosensitive element 1 during image formation by means of the relationship between the DC voltage at at least two points selected from the range where the absolute value of the DC voltage applied by the voltage application unit is 700V or more and the amount of charge movement under the DC voltage at said at least two points.

[0114] In the charged potential control unit 15 to be used in the present invention, there are no particular limitations on the method for determining the control variable for controlling the charged potential, but examples include methods such as those described in (1) and (2) below.

[0115] (1) The method involves estimating the discharge initiation voltage V from the relationship between the DC voltage at at least two points and the amount of charge movement per unit time. thAnd relative to the control target value V of the charged potential td The DC voltage V to be applied during image formation is determined based on the following formula (E-15). DC .

[0116] V DC =V th +V td (E-15)

[0117] (2) The method involves calculating the slope S, expressed by equation (E-16), from the relationship between the DC voltage at at least two points and the amount of charge movement per unit time, and determining the target value I of the amount of charge movement per unit time based on equation (E-17). t .

[0118] S=(I p -I q ) / (V p -V q (E-16)

[0119] I t =S×V td (E-17)

[0120] Preferably, the charged potential control unit 15 is configured to control the DC voltage to be applied during image formation by means of the relationship between the DC voltage applied by the voltage application unit at at least two points selected from the range of 700V or more and the amount of charge movement at the DC voltage at the at least two points.

[0121] Preferably, the charge potential control unit 15 is configured such that the relationship between the DC voltage applied by the voltage application unit at point "n", selected from a range with an absolute value of 700V or more, and the amount of charge movement under the DC voltage at said point "n" is approximated by a function with a degree of freedom of "n" or less; and the charge potential of the electrophotographic photosensitive component during image formation is controlled by using this function as a calibration curve. Here, "n" represents an integer of 2 or more. In this case, the function is more preferably a linear function.

[0122] Furthermore, the electrophotographic apparatus according to the present invention preferably satisfies the following condition to control the charged potential of the electrophotographic photosensitive component during image formation with higher precision. First, among the DC voltages applied by the voltage application unit at at least two points selected from the range of 700V or more absolute values, the DC voltage with the smallest absolute value is V. DC-min The DC voltage with the largest absolute value is represented by V. DC-MAX In addition, V DC-min The absolute value of the electric potential of the electrophotographic photosensitive element is given by V. dmIt indicates that, and V DC-MAX The absolute value of the electric potential of the electrophotographic photosensitive element is given by V. dM Indicates. At this time, V dm and V dM It is greater than V1 and equal to or less than V2. That is, V dm and V dM And V1 and V2 preferably satisfy the relationship expressed by the following equation (E-18).

[0123] V1 <V dm <V dM ≤V2(E-18)

[0124] In addition, V dm and V dM Furthermore, V1 and V2′ more preferably satisfy the relationship expressed by the following equation (E-19).

[0125] V1 <V dm <V dM ≤V2′(E-19)

[0126] [Electronic photographic sensor]

[0127] As a method for producing the electrophotographic photosensitive component used in the present invention, a method is provided involving: preparing a coating liquid for each layer described below, applying the coating liquid to a support in a desired layer sequence, and drying the coating liquid. In this case, as coating methods for the coating liquid, examples include dip coating, spray coating, inkjet coating, roller coating, die coating, blade coating, curtain coating, wire rod coating, and ring coating. Among these, dip coating is preferred from the viewpoint of efficiency and productivity.

[0128] The following describes the support structure and each layer.

[0129] <Support Body>

[0130] In this invention, the electrophotographic photosensitive component includes a conductive support. Furthermore, examples of the support's shape include cylindrical, strip-shaped, and sheet-shaped. A cylindrical support is preferred. Additionally, the surface of the support can be subjected to, for example, electrochemical treatments such as anodizing, sandblasting, or machining.

[0131] Materials such as metal, resin, or glass are preferred as the support.

[0132] Examples of metals include aluminum, iron, nickel, copper, gold, stainless steel, and their alloys. Among these, aluminum supports are preferred.

[0133] In addition, the resin or glass can be made conductive by processes involving, for example, mixing the resin or glass with a conductive material or coating the resin or glass with a conductive material.

[0134] <Conductive Layer>

[0135] In this invention, a conductive layer can be provided on the support. The conductive layer can shield the surface of the support from scratches and unevenness, and control the reflection of light on the surface of the support.

[0136] The conductive layer preferably comprises conductive particles and resin.

[0137] The conductive particles are made of materials such as metal oxides, metals, or carbon black.

[0138] Examples of metal oxides include zinc oxide, aluminum oxide, indium oxide, silicon oxide, zirconium oxide, tin oxide, titanium oxide, magnesium oxide, antimony oxide, and bismuth oxide. Examples of metals include aluminum, nickel, iron, nickel-chromium alloys, copper, zinc, and silver.

[0139] Preferably, metal oxides are used as conductive particles, and more particularly, titanium oxide, tin oxide and zinc oxide are preferred.

[0140] When using metal oxides as conductive particles, the surface of the metal oxides can be treated with silane coupling agents, or the metal oxides can be doped with elements such as phosphorus or aluminum, or their oxides.

[0141] Furthermore, each conductive particle can be a stack having a core particle and a coating layer covering the particle. Examples of core particles include titanium oxide, barium sulfate, and zinc oxide. The coating layer is, for example, a metal oxide, such as tin oxide.

[0142] Furthermore, when metal oxides are used as conductive particles, their volume average particle size is preferably 1 to 500 nm, more preferably 3 to 400 nm.

[0143] Examples of resins include polyester resins, polycarbonate resins, polyvinyl acetal resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, and alkyd resins.

[0144] In addition, the conductive layer may further contain masking agents such as silicone oil, resin particles, or titanium dioxide.

[0145] The thickness of the conductive layer is preferably 1 to 50 μm, and particularly preferably 3 to 40 μm.

[0146] A conductive layer can be formed by preparing a coating liquid containing the aforementioned materials and solvents, forming a coating film thereon, and drying the coating film. Examples of solvents used in the coating liquid include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Dispersion methods for dispersing conductive particles in the coating liquid for the conductive layer include, for example, methods using a paint mixer, a sand mill, a ball mill, or a high-speed liquid impact disperser.

[0147] <Undercoat>

[0148] In this invention, a primer layer can be formed on a conductive support or conductive layer. Forming a primer layer improves interlayer adhesion, thereby providing charge injection prevention.

[0149] The primer layer preferably comprises a resin. Alternatively, the primer layer can be formed into a cured film by polymerizing a composition comprising monomers having polymerizable functional groups.

[0150] Examples of resins include polyester resins, polycarbonate resins, polyvinyl alcohol acetal resins, acrylic resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinylphenolic resins, alkyd resins, polyvinyl alcohol resins, polyethylene oxide resins, polypropylene oxide resins, polyamide resins, polyamic acid resins, polyimide resins, polyamide-imide resins, and cellulose resins.

[0151] Examples of polymerizable functional groups in monomers include isocyanate groups, terminal isocyanate groups, hydroxymethyl groups, alkylated hydroxymethyl groups, epoxy groups, metal alkoxide groups, hydroxyl groups, amino groups, carboxyl groups, thiol groups, carboxylic anhydride groups, and carbon-carbon double bond groups.

[0152] Among them, polyamide resins are preferred, and polyamide resins soluble in alcohol-based solvents are even more preferred. For example, ternary (6-66-610) copolyamides, quaternary (6-66-610-12) copolyamides, N-methoxymethylated nylon, polymeric fatty acid polyamides, polymeric fatty acid polyamide block copolymers, and copolyamides having diamine components are preferred.

[0153] Furthermore, to improve electrical properties, the base layer may further include electron transport materials, metal oxides, metals, and conductive polymers. Electron transport materials and metal oxides are preferred because they are effective at extracting charge from the charge-generating layer even under low electric fields.

[0154] Examples of electron transport materials include quinone compounds, imide compounds, benzimidazole compounds, cyclopentadienylidene compounds, fluorenone compounds, xanthonesone compounds, benzophenone compounds, cyanovinyl compounds, halogenated aryl compounds, thiophene compounds, and boron-containing compounds. Electron transport materials with polymerizable functional groups can be used as electron transport materials and copolymerized with the aforementioned monomers with polymerizable functional groups to form a base coating as a cured film.

[0155] Examples of metal oxides include indium tin oxide, tin oxide, indium oxide, titanium oxide, zinc oxide, aluminum oxide, and silicon dioxide. Examples of metals include gold, silver, and aluminum.

[0156] In addition, the base coat may contain additives.

[0157] The thickness of the base coating is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and particularly preferably 0.5 to 3 μm.

[0158] The base coat can be formed by preparing a coating liquid containing the above-described materials and solvents, forming the coating film thereon, and drying and / or curing the coating film. Examples of solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.

[0159] <Photosensitive layer>

[0160] The photosensitive layer of an electrophotographic photosensitive component is mainly divided into (1) stacked photosensitive layer and (2) single-layer photosensitive layer. (1) Stacked photosensitive layer is a photosensitive layer containing a charge-generating layer containing a charge-generating substance and a charge-transporting layer containing a charge-transporting substance. (2) Single-layer photosensitive layer is a photosensitive layer containing both a charge-generating substance and a charge-transporting substance.

[0161] (1) Layered photosensitive layer

[0162] The stacked photosensitive layer has a charge generation layer and a charge transport layer.

[0163] (1-1) Charge generation layer

[0164] The charge-generating layer preferably comprises a charge-generating substance and a resin.

[0165] Examples of charge-generating substances include azo pigments, perylene pigments, polycyclic quinone pigments, indigo pigments, and phthalocyanine pigments. Among these, phthalocyanine pigments are preferred. Of the phthalocyanine pigments, hydroxygallium phthalocyanine pigments or titanium dioxide phthalocyanine pigments are preferred.

[0166] When using phthalocyanine pigments as charge-generating substances, if a dispersant is used in the grinding process during the preparation of the phthalocyanine pigment, the amount of the dispersant is preferably 10 to 50 times the mass of the phthalocyanine pigment. Examples of solvents used include: amide solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methylformamide, N-methylacetamide, and N-methylpropionamide; halogen solvents, such as chloroform; ether solvents, such as tetrahydrofuran; and sulfoxide solvents, such as dimethyl sulfoxide. Furthermore, the amount of solvent used is preferably 5 to 30 times the mass of the phthalocyanine pigment.

[0167] Examples of resins include polyester resins, polycarbonate resins, polyvinyl alcohol acetal resins, polyvinyl alcohol butyral resins, acrylic resins, silicone resins, epoxy resins, melamine resins, polyurethane resins, phenolic resins, polyvinyl alcohol resins, cellulose resins, polystyrene resins, polyvinyl acetate resins, and polyvinyl chloride resins. Among these, polyvinyl alcohol butyral resin is more preferred.

[0168] Furthermore, the charge-generating layer may further contain additives such as antioxidants or ultraviolet absorbers. Specific examples include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, and benzophenone compounds.

[0169] From the viewpoint of stabilizing the residual potential at a low level regardless of the magnitude of the charged potential, the average thickness of the charge generation layer of the present invention is preferably 0.12 μm or more, and more preferably 0.14 μm or more.

[0170] The charge-generating layer can be formed by preparing a coating solution containing the above-mentioned materials and solvents, forming a coating film thereon, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, sulfoxide-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents.

[0171] (1-2) Charge transport layer

[0172] The charge transport layer preferably comprises a charge transport material and a resin.

[0173] Examples of charge-transporting substances include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from each of these substances. Among these, compounds with an ionization potential of 5.2 to 5.4 eV are preferred for achieving the effects of this application. When the ionization potential is less than 5.2 eV, the electric field strength dependence α is relatively large, and in some cases, the memory phenomenon deteriorates after durability. When the ionization potential is greater than 5.4 eV, in some cases, the residual potential increases.

[0174] The ionization potential was measured by measuring the threshold energy required to release electrons using an atmospheric photoelectron spectrometer (product name: AC-2) manufactured by Richen Keiki Co., Ltd.

[0175] The content of charge transport material in the charge transport layer is preferably 25 to 70% by mass relative to the total mass of the charge transport layer, more preferably 30 to 55% by mass.

[0176] Examples of resins include polyester resins, polycarbonate resins, acrylic resins, and polystyrene resins. Among these, polycarbonate resins and polyester resins are preferred. As polyester resins, polyarylate resins are particularly preferred.

[0177] The ratio (mass ratio) of charge transport material to resin is preferably 4:10 to 20:10, more preferably 5:10 to 12:10.

[0178] In addition, the charge transport layer may contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, slip-improving agents, or abrasion resistance improvers. Specific examples include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluoropolymer particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0179] The average thickness of the charge transport layer is preferably 5 to 30 μm, more preferably 8 to 17 μm, and particularly preferably 10 to 14 μm.

[0180] The charge transport layer can be formed by preparing a coating solution containing the above-described materials and solvents, forming a coating film thereon, and drying the coating film. Examples of solvents used in the coating solution include alcohol-based solvents, ketone-based solvents, ether-based solvents, ester-based solvents, and aromatic hydrocarbon-based solvents. Among these solvents, ether-based solvents or aromatic hydrocarbon-based solvents are preferred.

[0181] (2) Single-layer photosensitive layer

[0182] A single-layer photosensitive layer can be formed by preparing a coating solution containing a charge-generating substance, a charge-transporting substance, a resin, and a solvent, forming the coating on a base layer, and drying the coating. Examples of charge-generating substances, charge-transporting substances, and resins are the same as those materials in section "(1) Laminated Photosensitive Layers".

[0183] <Protective Layer>

[0184] In this invention, a protective layer can be formed on the photosensitive layer. Forming a protective layer improves durability.

[0185] Preferably, the protective layer comprises conductive particles and / or charge-transporting substances, and resin.

[0186] Examples of conductive particles include particles of metal oxides such as titanium oxide, zinc oxide, tin oxide, and indium oxide.

[0187] Examples of charge-transporting substances include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and resins having groups derived from each of these substances. Among these, triarylamine compounds and benzidine compounds are preferred.

[0188] Examples of resins include polyester resins, acrylic resins, phenoxy resins, polycarbonate resins, polystyrene resins, phenolic resins, melamine resins, and epoxy resins. Among these, polycarbonate resins, polyester resins, and acrylic resins are preferred.

[0189] Furthermore, the protective layer can be formed into a cured film by polymerizing a composition containing monomers with polymerizable functional groups. Examples of reactions in this case include thermal polymerization, photopolymerization, and radiation polymerization. Examples of polymerizable functional groups in monomers include acryloyl and methacryloyl groups. Materials with charge-transporting capabilities can be used as monomers with polymerizable functional groups.

[0190] The protective layer may contain additives such as antioxidants, UV absorbers, plasticizers, leveling agents, slip-improving agents, or abrasion resistance enhancers. Specific examples include hindered phenolic compounds, hindered amine compounds, sulfur compounds, phosphorus compounds, benzophenone compounds, siloxane-modified resins, silicone oils, fluoropolymer particles, polystyrene resin particles, polyethylene resin particles, silica particles, alumina particles, and boron nitride particles.

[0191] The average thickness of the protective layer is preferably 0.5 to 5 μm, more preferably 1 to 3 μm.

[0192] A protective layer can be formed by preparing a coating liquid containing the above-mentioned materials and solvents, forming a coating film thereon, and drying and / or curing the coating film. Examples of solvents used in the coating liquid include alcohol solvents, ketone solvents, ether solvents, sulfoxide solvents, ester solvents, and aromatic hydrocarbon solvents.

[0193] Preferably, the electrophotographic photosensitive component of the present invention sequentially comprises a support, a base coating, a charge generating layer, and a charge transport layer, wherein the base coating comprises polyamide resin and metal oxide particles. Furthermore, it is preferred that the metal oxide particles are titanium oxide particles, and each titanium oxide particle is spherical in shape, and from the viewpoint of suppressing charge accumulation and uniform dispersion, its average primary particle size is preferably 10 to 100 nm. Furthermore, the thickness of the base coating is preferably 0.5 to 3.0 μm.

[0194] From the viewpoint of suppressing the rise of residual potential, the crystal structure of the titanium dioxide used to form the above-mentioned titanium dioxide particles is preferably rutile or anatase, and more preferably rutile, which has weak photocatalytic activity. In the case of rutile, the rutile content of the particles is preferably 90% or more. From the viewpoint of dispersibility, the titanium dioxide particles can be treated with silane coupling agents or the like. For example, surface treatment of the titanium dioxide particles with vinylsilane is preferred because it achieves the effect of extracting charge from the charge-generating layer even under low electric fields, and thus stabilizes the residual potential at a low level.

[0195] Furthermore, preferably, the charge-generating layer comprises a titanium phthalocyanine pigment, and the titanium phthalocyanine pigment is a titanium phthalocyanine pigment that satisfies the following conditions: The titanium phthalocyanine pigment comprises crystal particles, each having a crystal form exhibiting peaks at Bragg angles 2θ of 9.8°±0.3° and 27.1°±0.3° in X-ray diffraction spectra using CuKα rays. Furthermore, the titanium phthalocyanine pigment has a peak A in the range of 50–150 nm in the crystal grain size distribution measured using small-angle X-ray scattering, and the half-width of peak A is less than 100 nm.

[0196] Furthermore, preferably, the charge-generating layer comprises a hydroxy gallium phthalocyanine pigment, and the hydroxy gallium phthalocyanine pigment is a hydroxy gallium phthalocyanine pigment that satisfies the following conditions: The hydroxy gallium phthalocyanine pigment comprises crystal particles, each having a crystal form exhibiting peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in X-ray diffraction using CuKα rays. Furthermore, the hydroxy gallium phthalocyanine pigment has a peak B in the crystal grain size distribution measured using small-angle X-ray scattering in the range of 20–50 nm, and the half-width of peak B is less than 50 nm.

[0197] Powder X-ray diffraction measurements of phthalocyanine pigments can be performed under the following conditions.

[0198] (Powder X-ray diffraction measurement)

[0199] Measuring equipment used: RINT-TTRII X-ray diffraction equipment manufactured by Rigaku Corporation.

[0200] X-ray tube: Cu

[0201] X-ray wavelength: Kα1

[0202] Tube voltage: 50KV

[0203] Tube current: 300mA

[0204] Scanning method: 2θ scan

[0205] Scanning speed: 4.0° / min

[0206] Sampling interval: 0.02°

[0207] Initial angle 2θ: 5.0°

[0208] Termination angle 2θ: 35.0°

[0209] Goniometer: Rotor Horizontal Goniometer (TTR-2)

[0210] Attachment: Capillary Rotating Sample Stage

[0211] Filter: Not used

[0212] Detector: Blink Counter

[0213] Incident monochromator: using

[0214] Slit: Variable slit (parallel beam method)

[0215] Counter monochromator: Not used

[0216] Diverging slit: Open

[0217] Diverging vertical limiting slit: 10.00mm

[0218] Scattering slit: Open

[0219] Light receiving slit: Open

[0220] According to the present invention, an electrophotographic apparatus is provided that can control the charged potential of an electrophotographic photosensitive element during image formation with high precision in a short time.

[0221] Example

[0222] The invention is described in more detail below by way of examples and comparative examples. The invention is by no means limited to the following examples, and various modifications can be made without departing from the spirit of the invention. In the description of the following examples, unless otherwise stated, the term "parts" refers to a quantity by weight.

[0223] Apart from the charge-generating layer, the thicknesses of each layer of the electrophotographic photosensitive component according to the embodiments and comparative examples are determined by either a method involving the use of an eddy current thickness gauge (Fischerscope, manufactured by Fischer Instruments KK) or a method involving converting the mass of the layer per unit area to its thickness by using the specific gravity of the layer. The thickness of the charge-generating layer is measured by converting the Macbeth concentration value of the electrophotographic photosensitive component into a calibration curve obtained in advance by observing the layer thickness value measured by observing its cross-sectional SEM image. In this document, the Macbeth concentration value is measured by pressing a spectrophotometer (product name: X-Rite 504 / 508, manufactured by X-Rite) against the surface of the electrophotographic photosensitive component.

[0224] [Example of preparation of coating liquid 1 for primer layer]

[0225] 100 parts of rutile titanium dioxide particles (average primary particle size: 50 nm, manufactured by Tayca Corporation) were mixed with 500 parts of toluene, and 3.0 parts of methyldimethoxysilane (“TSL8117”, manufactured by Toshiba Silicone Co., Ltd.) were added to the mixture, which was then stirred for 8 hours. Subsequently, the toluene was distilled off by vacuum distillation, and the residue was dried at 120°C for 3 hours. This yielded rutile titanium dioxide particles with a surface treated with methyldimethoxysilane.

[0226] Next, prepare the following materials.

[0227] • 18 parts of rutile titanium dioxide particles with surface treated with methyldimethoxysilane

[0228] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0229] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0230] 1.5 copies

[0231] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then dispersed for 6 hours using a vertical sand mill with glass beads of 1.0 mm diameter each. The sand-milled dispersion was then further dispersed for 1 hour using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) to prepare a base coat coating liquid 1. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0232] [Example of preparation of coating liquid 2 for primer layer]

[0233] Except for changing the sand mill dispersion time to 4 hours in the preparation example of the primer coating liquid 1, the primer coating liquid 2 is prepared in the same manner as the primer coating liquid 1.

[0234] [Example of preparation of coating liquid 3 for primer layer]

[0235] 100 parts of rutile titanium dioxide particles (average primary particle size: 15 nm, manufactured by Tayca Corporation) were mixed with 500 parts of toluene, and 9.6 parts of methyldimethoxysilane (“TSL8117”, manufactured by Toshiba Silicone Co., Ltd.) were further added to the mixture, which was then stirred for 8 hours. Subsequently, the toluene was distilled off by vacuum distillation, and the residue was dried at 120°C for 3 hours. This yielded rutile titanium dioxide particles with a surface treated with methyldimethoxysilane.

[0236] Next, prepare the following materials.

[0237] • Six parts of rutile titanium dioxide particles with surface treated with methyldimethoxysilane

[0238] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0239] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0240] 1.5 copies

[0241] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then dispersed for 6 hours using a vertical sand mill with glass beads of 1.0 mm diameter. The sand-milled dispersion was then further dispersed for 1 hour using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) to prepare a base coat coating liquid 3. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0242] [Example of preparation of coating liquid 4 for primer layer]

[0243] Except for changing the sand mill dispersion time to 4 hours in the preparation example of the primer coating liquid 2, the primer coating liquid 4 is prepared in the same manner as the primer coating liquid 2.

[0244] [Example of preparation of coating liquid 5 for primer layer]

[0245] 100 parts of rutile titanium dioxide particles (average primary particle size: 35 nm, manufactured by Tayca Corporation) were mixed with 500 parts of toluene, and 4.32 parts of methyldimethoxysilane (“TSL8117”, manufactured by Toshiba Silicone Co., Ltd.) were further added to the mixture, followed by stirring for 8 hours. Subsequently, the toluene was distilled off by vacuum distillation, and the residue was dried at 120°C for 3 hours. This yielded rutile titanium dioxide particles with a surface treated with methyldimethoxysilane.

[0246] Next, prepare the following materials.

[0247] • 12 parts of rutile titanium dioxide particles with surface treated with methyldimethoxysilane

[0248] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0249] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0250] 1.5 copies

[0251] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then treated with a vertical sand mill using glass beads, each with a diameter of 1.0 mm, for 6 hours. The sand-milled liquid was then further dispersed using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) for 1 hour to prepare a base coat coating liquid 5. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0252] [Example of preparation of coating liquid 6 for primer layer]

[0253] Except for changing the sand mill dispersion time to 4 hours in the preparation example of the primer coating liquid 5, the primer coating liquid 6 is prepared in the same manner as the primer coating liquid 5.

[0254] [Example of preparation of coating liquid 7 for primer layer]

[0255] 100 parts of rutile titanium dioxide particles (average primary particle size: 80 nm, manufactured by Tayca Corporation) were mixed with 500 parts of toluene, and 1.8 parts of methyldimethoxysilane (“TSL8117”, manufactured by Toshiba Silicone Co., Ltd.) were further added to the mixture, which was then stirred for 8 hours. Subsequently, the toluene was distilled off by vacuum distillation, and the residue was dried at 120°C for 3 hours. This yielded rutile titanium dioxide particles with a surface treated with methyldimethoxysilane.

[0256] Next, prepare the following materials.

[0257] • 18 parts of rutile titanium dioxide particles with surface treated with methyldimethoxysilane

[0258] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0259] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0260] 1.5 copies

[0261] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then treated with a vertical sand mill using glass beads of 1.0 mm diameter for 6 hours. The sand-milled liquid was then further dispersed using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) for 1 hour to prepare a base coat coating liquid 7. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0262] [Example of preparation of coating liquid 8 for primer layer]

[0263] Except for changing the sand mill dispersion time to 4 hours in the preparation example of the primer coating liquid 7, the primer coating liquid 8 is prepared in the same manner as the primer coating liquid 7.

[0264] [Example of preparation of coating liquid 9 for primer layer]

[0265] 100 parts of rutile titanium dioxide particles (average primary particle size: 120 nm, manufactured by Tayca Corporation) were mixed with 500 parts of toluene, and 1.8 parts of methyldimethoxysilane (“TSL8117”, manufactured by Toshiba Silicone Co., Ltd.) were further added to the mixture, which was then stirred for 8 hours. Subsequently, the toluene was distilled off by vacuum distillation, and the residue was dried at 120°C for 3 hours. This yielded rutile titanium dioxide particles with a surface treated with methyldimethoxysilane.

[0266] Next, prepare the following materials.

[0267] • 18 parts of rutile titanium dioxide particles with surface treated with methyldimethoxysilane

[0268] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0269] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0270] 1.5 copies

[0271] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then dispersed for 6 hours using a vertical sand mill with glass beads of 1.0 mm diameter each. The sand-milled liquid was then further dispersed for 1 hour using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) to prepare a base coat coating liquid 9. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0272] [Example of preparation of coating liquid 10 for primer layer]

[0273] Except for replacing methyldimethoxysilane with vinyltrimethoxysilane (product name: KBM-1003, manufactured by Shin-Etsu Chemical Co., Ltd.) in the preparation example of primer coating liquid 1, primer coating liquid 10 is prepared in the same manner as primer coating liquid 1.

[0274] [Example of preparation of coating liquid 11 for primer layer]

[0275] Except for changing the sand mill dispersion time to 4 hours in the preparation example of the primer coating liquid 10, the primer coating liquid 11 is prepared in the same manner as the primer coating liquid 10.

[0276] [Example of preparation of coating liquid 12 for primer layer]

[0277] Prepare the following materials.

[0278] Rutile titanium dioxide particles (average primary particle size: 50 nm, manufactured by Tayca Corporation)

[0279] 18 copies

[0280] • 4.5 parts of N-methoxymethylated nylon (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation)

[0281] • Copolymer nylon resin (product name: AMILAN CM8000, manufactured by Toray Industries, Inc.)

[0282] 1.5 copies

[0283] These materials were added to a mixed solvent of 90 parts methanol and 60 parts 1-butanol to prepare a dispersion. The dispersion was then dispersed for 6 hours using a vertical sand mill with glass beads of 1.0 mm diameter each. The liquid, which had undergone sand mill dispersion as described above, was then further dispersed for 1 hour using an ultrasonic disperser (UT-205, manufactured by Sharp Corporation) to prepare a base coat coating liquid 12. The output of the ultrasonic disperser was set to 100%. Furthermore, media such as glass beads were not used in this dispersion process.

[0284] [Example of preparation of coating liquid 13 for primer layer]

[0285] 25 parts of N-methoxymethylated nylon 6 (product name: TORESIN EF-30T, manufactured by Nagase ChemteX Corporation) were dissolved in 480 parts of a methanol / n-butanol = 2 / 1 mixed solution by heating to 65°C. The resulting solution was then cooled to room temperature. The cooled solution was then filtered through a membrane filter (product name: FP-022, pore size: 0.22 μm, manufactured by Sumitomo Electric Industries, Ltd.) to prepare a coating solution 13 for the primer layer.

[0286] Synthesis of Phthalocyanine Pigments

[0287] [Synthesis example 1]

[0288] Under a nitrogen atmosphere, 5.46 parts of phthalonitrile and 45 parts of α-chloronaphthalene were added to a reaction vessel. The mixture was then heated to 30°C and maintained at 30°C. Next, at 30°C, 3.75 parts of gallium trichloride were added to the reaction vessel. The water concentration of the mixture in the reaction vessel at the time of addition was 150 ppm. The temperature in the reaction vessel was then raised to 200°C. The product was then reacted at 200°C for 4.5 hours under a nitrogen atmosphere, followed by cooling. When the temperature reached 150°C, the product was filtered. The filtered product was dispersed and washed with N,N-dimethylformamide at 140°C for 2 hours, followed by filtration. The filtered product was washed with methanol and then dried to provide gallium chlorophthalocyanine pigment in 71% yield.

[0289] [Synthesis example 2]

[0290] 4.65 parts of the gallium chlorophthalocyanine pigment obtained in Synthesis Example 1 above were dissolved in 139.5 parts of concentrated sulfuric acid at 10°C. The resulting solution was added dropwise to 620 parts of ice water with stirring to induce re-precipitation. The solution containing the precipitate was filtered under reduced pressure using a filter press. A No. 5C filter (manufactured by Advantec) was used as the filter. The resulting filtered product was dispersed and washed with 2% ammonia for 30 minutes, and then filtered again using a filter press. Next, the resulting filtered product was dispersed and washed with deionized water, and then filtered three times repeatedly using a filter press. Finally, the result was freeze-dried to provide a hydroxy gallium phthalocyanine pigment (aqueous hydroxy gallium phthalocyanine pigment) with a solid content of 23% in 97% yield.

[0291] [Synthesis example 3]

[0292] As described below, 6.6 kg of the hydroxy gallium phthalocyanine pigment obtained in the above synthesis example 2 was dried using an ultra-dry dryer (product name: HD-06R, frequency (oscillation frequency): 2,455MHz±15MHz, manufactured by Biocon (Japan) Ltd.).

[0293] Immediately after being removed from the filter press, the hydroxygallium phthalocyanine pigment is placed in clumps (water-containing filter cake thickness: less than 4 cm) on a dedicated circular plastic tray. A dryer is then set up to shut off far-infrared radiation, and the temperature of the dryer's inner wall is increased to 50°C. Then, while irradiating the pigment with microwaves, the dryer's vacuum pump and leak valve are adjusted to maintain a vacuum level between 4.0 and 10.0 kPa.

[0294] First, as the first step, the hydroxygallium phthalocyanine pigment is irradiated with a microwave with an output of 4.8 kW for 50 minutes. Next, the microwave is temporarily shut off, and the leakage valve is temporarily closed to achieve a high vacuum below 2 kPa. At this point, the solid content of the hydroxygallium phthalocyanine pigment is 88%.

[0295] As a second step, the leak valve is adjusted to bring the vacuum level (pressure inside the dryer) to the aforementioned preset range (4.0–10.0 kPa). Then, the hydroxygallium phthalocyanine pigment is irradiated with a microwave with an output of 1.2 kW for 5 minutes. Furthermore, the microwave is temporarily turned off, and the leak valve is temporarily closed to achieve a high vacuum below 2 kPa. This second step is repeated once more (a total of two times). At this point, the solid content of the hydroxygallium phthalocyanine pigment is 98%.

[0296] In addition, as the third step, microwave irradiation is performed in the same manner as in the second step, except that the microwave output in the second step is changed from 1.2kW to 0.8kW. The third step is then repeated once more (a total of two times).

[0297] In addition, as the fourth step, the leakage valve is adjusted to restore the vacuum level (pressure inside the dryer) to the aforementioned preset range (4.0–10.0 kPa). Afterward, the hydroxygallium phthalocyanine pigment is irradiated with a microwave with an output of 0.4 kW for 3 minutes. Then, the microwave is temporarily turned off, and the leakage valve is temporarily closed to achieve a high vacuum of less than 2 kPa. This fourth step is repeated 7 times (a total of 8 times).

[0298] Thus, 1.52 kg of hydroxy gallium phthalocyanine pigment (crystals) with a water content of less than 1% was obtained in a total of 3 hours.

[0299] [Synthesis Example 4]

[0300] In 100 g of α-chloronaphthalene, 5.0 g of phthalonitrile and 2.0 g of titanium tetrachloride were heated and stirred at 200 °C for 3 hours, and then cooled to 50 °C. The crystals precipitated by cooling were separated by filtration to provide a paste of titanium tetrachloride phthalocyanine. Next, the resulting paste was stirred and washed with 100 mL of N,N-dimethylformamide heated to 100 °C, and then washed twice repeatedly with 100 mL of methanol at 60 °C, and then separated by filtration. In addition, the paste obtained by filtration was stirred in 100 mL of deionized water at 80 °C for 1 hour, and then separated by filtration to provide 4.3 g of blue titanium tetrachloride phthalocyanine pigment.

[0301] Next, the obtained blue titanium phthalocyanine pigment was dissolved in 30 mL of concentrated sulfuric acid, and the solution was added dropwise to 300 mL of deionized water at 20 °C with stirring to precipitate again. The solution containing the precipitate was then filtered and thoroughly washed with water to provide amorphous titanium phthalocyanine pigment. 4.0 g of the amorphous titanium phthalocyanine pigment was suspended in 100 mL of methanol and stirred at room temperature (22 °C) for 8 hours. The resulting product was then separated by filtration and dried under reduced pressure to provide titanium phthalocyanine pigment with low crystallinity.

[0302] [Synthesis example 5]

[0303] Under a nitrogen atmosphere, 10 g of gallium trichloride and 29.1 g of phthalonitrile were added to 100 mL of α-chloronaphthalene, and the mixture was reacted at 200 °C for 24 hours. The product was then filtered. The filtered product was heated and stirred at 150 °C for 30 minutes using N,N-dimethylformamide, and then filtered again. The filtered product was washed with methanol and then dried to provide gallium chlorophthalocyanine pigment in 83% yield.

[0304] Two parts of gallium chlorophthalocyanine pigment obtained by the above method were dissolved in 50 parts of concentrated sulfuric acid, and the mixture was stirred for 2 hours. The resulting solution was then added dropwise to an ice-cold mixture of 170 mL distilled water and 66 mL concentrated ammonia to precipitate again. The solution containing the precipitate was thoroughly washed with distilled water and dried to provide 1.8 parts of hydroxygallium phthalocyanine pigment.

[0305] [Example of preparation of coating solution 1 for charge generation layer]

[0306] Prepare the following materials.

[0307] • 0.5 parts of the hydroxygallium phthalocyanine pigment obtained in Synthesis Example 3

[0308] • N-methylformamide (product code: F0059, manufactured by Tokyo Chemical Industry Co., Ltd.) 9.5 parts

[0309] · 15 portions of glass beads, each with a diameter of 0.9 mm.

[0310] The materials were milled for 6 hours at room temperature (23°C) using a paint mixer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) (first stage). A standard bottle (product name: PS-6, manufactured by Hakuyo Glass Co., Ltd.) was used as the container. The milled liquid was then milled in a ball mill for 100 hours at room temperature (23°C) (second stage). The container was left in the ball mill without removing its contents, and the process was carried out at 120 rotations per minute. Therefore, the same glass beads as in the first stage were used in the second stage milling process. The treated liquid was filtered through a filter (product number: N-NO.125T, pore size: 133 μm, manufactured by NBC Meshtec Inc.) to remove the glass beads. 30 parts of N-methylformamide were added to the filtered solution. The mixture was then filtered, and the product collected through the filter unit was thoroughly washed with tetrahydrofuran. The washed and filtered product was then dried in a vacuum to provide 0.46 parts of hydroxygallium phthalocyanine pigment.

[0311] The obtained hydroxygallium phthalocyanine pigment exhibits peaks at the following positions in the X-ray diffraction spectrum using CuKα rays: specifically, the hydroxygallium phthalocyanine pigment has peaks at Bragg angles 2θ of 7.4°±0.3°, 9.9°±0.3°, 16.2°±0.3°, 18.6°±0.3°, 25.2°±0.3°, and 28.2°±0.3°.

[0312] In addition, through 1The estimated N-methylformamide content in the hydroxygallium phthalocyanine crystal particles by H-NMR measurement was 1.9% by mass relative to the hydroxygallium phthalocyanine content.

[0313] Next, prepare the following materials.

[0314]

[0315] These materials were dispersed for 4 hours at 18°C ​​using a sand mill (K-800, manufactured by Igarashi Machine Production Co., Ltd. (now Aimex Co., Ltd.), with a disc diameter of 70 mm and 5 discs). During this process, the discs were rotated at 1,800 times per minute. 444 parts of cyclohexanone and 634 parts of ethyl acetate were added to the dispersion to prepare coating solution 1 for the charge-generating layer.

[0316] The measurement of phthalocyanine pigments using small-angle X-ray scattering is performed through the following procedure.

[0317] First, the prepared charge-generating layer is diluted with coating solution 1 by adding cyclohexanone until the concentration of the charge-generating substance becomes 1% by mass. Thus, a measurement sample is prepared.

[0318] The obtained sample was subjected to small-angle X-ray scattering measurements (X-ray wavelength: 0.154 nm) using a SmartLab multi-functional X-ray diffractometer manufactured by Rigaku Corporation.

[0319] The scattering curves obtained through measurement were analyzed using the particle size analysis software NANO-Solver to provide the crystal grain size distribution. The particle shape was assumed to be spherical.

[0320] According to the measurement results, the hydroxy gallium phthalocyanine pigment contained in the coating liquid 1 of the charge generation layer has a peak at 38 nm in the crystal grain size distribution measured by small-angle X-ray scattering, and the half-width of the peak is 38 nm.

[0321] [Example of preparation of coating solution 2 for charge generation layer]

[0322] Except for changing the ball milling treatment in the second stage from 100 hours to 1,000 hours in the preparation example of coating liquid 1 for the charge generation layer, coating liquid 2 for the charge generation layer was prepared in the same manner as coating liquid 1 for the charge generation layer. The hydroxy gallium phthalocyanine pigment contained in coating liquid 2 has a peak at 33 nm in the crystal grain size distribution measured using small-angle X-ray scattering, and the half-width of the peak is 35 nm.

[0323] In addition, through1 The estimated N-methylformamide content in the hydroxygallium phthalocyanine crystal particles by H-NMR measurement was 1.5% by mass relative to the hydroxygallium phthalocyanine content.

[0324] [Example of preparation of coating solution 3 for charge generation layer]

[0325] Except for changing the ball milling treatment in the second stage from 100 hours to 2,000 hours in the preparation example of the coating liquid 1 for the charge generation layer, the coating liquid 3 for the charge generation layer was prepared in the same manner as the coating liquid 1 for the charge generation layer. The hydroxy gallium phthalocyanine pigment contained in the coating liquid 3 has a peak at 27 nm in the crystal grain size distribution measured using small-angle X-ray scattering, and the half-width of the peak is 35 nm.

[0326] In addition, through 1 The estimated N-methylformamide content in the hydroxygallium phthalocyanine crystal particles by H-NMR measurement was 1.5% by mass relative to the hydroxygallium phthalocyanine content.

[0327] [Example of preparation of coating solution 4 for charge generation layer]

[0328] Prepare the following materials.

[0329] • In the preparation example of coating liquid 3 for charge generation layer, 25 parts of hydroxy gallium phthalocyanine pigment were obtained by grinding.

[0330] • 5 parts of polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.)

[0331] · 190 parts of cyclohexanone

[0332] These materials were placed in a centrifuge container and centrifuged for 30 minutes at a preset temperature of 18°C ​​using a high-speed refrigerated centrifuge (product name: himac CR22G, manufactured by Hitachi Koki Co. Ltd.). During this process, the rotor was used with a product available under the product name R14A (manufactured by Hitachi Koki Co. Ltd.) at the shortest acceleration and deceleration times and a speed of 1,800 rpm. The supernatant after centrifugation was immediately collected in another centrifuge container. The resulting solution was then centrifuged again in the same manner as described above, except at a speed of 8,000 rpm. The supernatant after centrifugation was removed, and the remaining solution was immediately collected in another sample vial. The weight ratio of hydroxyl gallium phthalocyanine pigment to polyvinyl butyral in the resulting solution was determined by... 1The solid content of the resulting solution was determined by ¹H-NMR measurement. Furthermore, the solid content of the solution was determined by drying it in a dryer set to 150°C for 30 minutes and measuring the weight difference before and after drying.

[0333] Subsequently, polyvinyl butyral (product name: S-LEC BX-1, manufactured by Sekisui Chemical Co., Ltd.) and cyclohexanone were added to the solution obtained by centrifugation. At this point, the weight ratio of hydroxygallium phthalocyanine pigment, polyvinyl butyral, and cyclohexanone was set to 20:10:190 (hydroxygallium phthalocyanine pigment: polyvinyl butyral: cyclohexanone). 220 parts of the resulting solution and 482 parts of glass beads, each with a diameter of 0.9 mm, were dispersed for 4 hours using a sand mill (K-800, manufactured by IgarashiMachine Production Co., Ltd. (now changed to Aimex Co., Ltd.), disc diameter: 70 mm, number of discs: 5) at a cooling water temperature of 18°C. During this process, the discs were rotated 1,800 times per minute. 444 parts of cyclohexanone and 634 parts of ethyl acetate were added to the dispersion to prepare a coating solution 4 for the charge-generating layer. The hydroxy gallium phthalocyanine pigment contained in the coating liquid 4 of the charge generation layer has a peak at 20 nm in the crystal grain size distribution measured by small-angle X-ray scattering, and the half-width of the peak is 27 nm.

[0334] [Example of preparation of coating solution 5 for charge generation layer]

[0335] The hydroxy gallium phthalocyanine pigment prepared before the centrifugation process in the preparation example of coating liquid 4 for the charge generation layer is changed to the hydroxy gallium phthalocyanine pigment obtained as described below. Except as described above, coating liquid 5 for the charge generation layer is prepared in the same manner as in the preparation example of coating liquid 4 for the charge generation layer.

[0336] First, prepare the following materials.

[0337] • 0.5 parts of the hydroxygallium phthalocyanine pigment obtained in Synthesis Example 3

[0338] • N-methylformamide (product code: F0059, manufactured by Tokyo Chemical Industry Co., Ltd.) 9.5 parts

[0339] · 15 portions of glass beads, each with a diameter of 0.9 mm.

[0340] These materials were milled in a ball mill at room temperature (23°C) for 100 hours. During this time, the mixture was processed using a standard bottle (product name: PS-6, manufactured by Hakuyo Glass Co., Ltd.) at a rotation speed of 60 times per minute. The resulting liquid was filtered through a filter (product number: N-NO.125T, pore size: 133 μm, manufactured by NBC Meshtec Inc.) to remove glass beads. 30 parts of N-methylformamide were added to the resulting filtrate. The mixture was then filtered, and the product collected through the filter unit was thoroughly washed with tetrahydrofuran. The washed product collected through the filter was then dried under vacuum to provide 0.45 parts of hydroxygallium phthalocyanine pigment.

[0341] The hydroxygallium phthalocyanine pigment obtained above exhibits peaks at the following positions in the X-ray diffraction spectrum using CuKα rays: specifically, the hydroxygallium phthalocyanine pigment obtained above exhibits peaks at Bragg angles 2θ of 7.4°±0.3°, 9.9°±0.3°, 16.2°±0.3°, 18.6°±0.3°, 25.2°±0.3°, and 28.2°±0.3°.

[0342] The hydroxygallium phthalocyanine pigment contained in the coating solution 5 for the charge generation layer has a peak at 41 nm in the crystal grain size distribution measured using small-angle X-ray scattering, and the peak half-width is 40 nm. Furthermore, through... 1 The estimated N-methylformamide content in the hydroxygallium phthalocyanine crystal particles by H-NMR measurement was 2.1% by mass relative to the hydroxygallium phthalocyanine content.

[0343] [Example of preparation of coating solution 6 for charge generation layer]

[0344] Except for changing the ball milling treatment time from 100 hours to 40 hours in the preparation example of the coating liquid 5 for the charge generation layer, the coating liquid 6 for the charge generation layer was prepared in the same manner as the coating liquid 5 for the charge generation layer. The hydroxy gallium phthalocyanine pigment contained in the coating liquid 6 has a peak at 55 nm in the crystal grain size distribution measured using small-angle X-ray scattering, and the half-width of the peak is 49 nm.

[0345] [Example of preparation of coating solution 7 for charge generation layer]

[0346] Except for changing the process of obtaining hydroxy gallium phthalocyanine pigment as described below in the preparation example of coating liquid 1 for charge generation layer, coating liquid 7 for charge generation layer is prepared in the same manner as coating liquid 1 for charge generation layer.

[0347] First, prepare the following materials.

[0348] • 0.5 parts of the hydroxygallium phthalocyanine pigment obtained in Synthesis Example 5

[0349] ·N,N-Dimethylformamide (Product Code: D0722, manufactured by Tokyo Chemical Industry Co., Ltd.) 7.5 parts

[0350] • 29 glass beads, each with a diameter of 0.9 mm

[0351] These materials were ball-milled for 24 hours at 25°C. During this time, the mixture was processed using a standard bottle (product name: PS-6, manufactured by Hakuyo Glass Co., Ltd.) at a rotation speed of 60 times per minute. The resulting liquid was filtered through a filter (product number: N-NO.125T, pore size: 133 μm, manufactured by NBC Meshtec Inc.) to remove glass beads. 30 parts of N,N-dimethylformamide were added to the resulting filtrate. The mixture was then filtered, and the product collected through the filter unit was thoroughly washed with n-butyl acetate. The washed product collected through the filter was then dried under vacuum to provide 0.45 parts of hydroxygallium phthalocyanine pigment.

[0352] The hydroxy gallium phthalocyanine pigment contained in the coating liquid 7 of the charge generation layer has a peak at 60 nm in the crystal grain size distribution measured by small-angle X-ray scattering, and the half-width of the peak is 58 nm.

[0353] [Example of preparation of coating solution 8 for charge generation layer]

[0354] Prepare the following materials.

[0355] • 0.5 parts of the titanium dioxide phthalocyanine pigment obtained in Synthesis Example 4

[0356] 10 parts of tetrahydrofuran

[0357] · 15 portions of glass beads, each with a diameter of 0.9 mm.

[0358] These materials were milled for 48 hours at 18°C ​​using a sand mill (K-800, manufactured by Igarashi Machine Production Co., Ltd. (now Aimex Co., Ltd.), with a disc diameter of 70 mm and 5 discs). During this process, the discs rotated at 500 revolutions per minute. The resulting liquid was filtered through a filter (part number: N-NO.125T, pore size: 133 μm, manufactured by NBC Meshtec Inc.) to remove glass beads. 30 parts of tetrahydrofuran were added to the resulting filtrate. The mixture was then filtered, and the product collected through the filter unit was thoroughly washed with methanol and water. The washed product collected through the filter was then dried under vacuum to provide 0.46 parts of titanium dioxide phthalocyanine pigment. The obtained titanium phthalocyanine pigment has peaks at Bragg angles of 2θ° of 9.8°±0.3° and 27.1°±0.3° in the X-ray diffraction spectrum using CuKα rays.

[0359] Next, prepare the following materials.

[0360]

[0361] These materials were dispersed for 4 hours at 18°C ​​using a sand mill (K-800, manufactured by Igarashi Machine Production Co., Ltd. (now Aimex Co., Ltd.), with a disc diameter of 70 mm and 5 discs). During this process, the discs were rotated at 1,800 times per minute. 326 parts of cyclohexanone and 465 parts of ethyl acetate were added to the dispersion to prepare a coating solution 8 for the charge-generating layer.

[0362] The oxygen titanium phthalocyanine pigment contained in the coating liquid 8 of the charge generation layer has a peak at 70 nm in the crystal grain size distribution measured by small-angle X-ray scattering, and the half-width of the peak is 90 nm.

[0363] [Example of preparation of coating solution 9 for charge generation layer]

[0364] Prepare the following materials.

[0365]

[0366] These materials were dispersed for 4 hours at 18°C ​​using a sand mill (K-800, manufactured by Igarashi Machine Production Co., Ltd. (now Aimex Co., Ltd.), with a disc diameter of 70 mm and 5 discs). During this process, the discs were rotated at 1,800 times per minute. 326 parts of cyclohexanone and 465 parts of ethyl acetate were added to the dispersion to prepare a coating solution 9 for the charge-generating layer.

[0367] The oxygen titanium phthalocyanine pigment contained in the coating liquid 9 of the charge generation layer has a peak at 100 nm in the crystal grain size distribution measured by small-angle X-ray scattering, and the half-width of the peak is 140 nm.

[0368] [Example of preparation of coating solution 1 for charge transport layer]

[0369] Prepare the following materials.

[0370] • Five parts of a triarylamine compound represented by the following formula (A1) used as a charge transport substance

[0371] • Five parts of a triarylamine compound represented by the following formula (A2) used as a charge transport substance

[0372] • 10 parts of polycarbonate (product name: IUPILON Z-400, manufactured by Mitsubishi Engineering-Plastics Corporation)

[0373]

[0374]

[0375] These materials were dissolved in a mixed solvent of 25 parts o-xylene, 25 parts methyl benzoate and 25 parts dimethoxymethane to prepare a coating solution 1 for the charge transport layer.

[0376] [Example of preparation of coating solution 2 for charge transport layer]

[0377] Prepare the following materials.

[0378] • 90 parts of charge-transporting material represented by the following formula (A10) used as charge-transporting material

[0379] • 100 parts of polyarylate resin having structural units represented by formula (A11) and structural units represented by formula (A12) in a 5:5 ratio and having a weight-average molecular weight of 100,000.

[0380]

[0381] These materials were dissolved in a mixed solvent of 300 parts dimethoxymethane and 700 parts chlorobenzene to prepare a coating solution 2 for the charge transport layer.

[0382] [Example of preparation of coating solution 3 for charge transport layer]

[0383] Prepare the following materials.

[0384]

[0385]

[0386] These materials were dissolved in a mixed solvent of 640 parts tetrahydrofuran and toluene (weight ratio: 8 / 2) to prepare a coating solution 3 for the charge transport layer.

[0387] [Example of preparation of coating liquid 1 for protective layer]

[0388] Prepare the following materials.

[0389] • 24 parts of the compound represented by the following formula (4-1)

[0390] • Siloxane-modified acrylic compounds (SYMAC US-270, manufactured by Toagosei Co., Ltd.)

[0391] 1.2 portions

[0392] These materials were mixed with a mixed solvent of 42 parts cyclohexane and 18 parts 1-propanol, and the mixture was stirred to prepare a protective coating solution 1.

[0393]

[0394] [Example 1 of Electrophotographic Photosensitive Component Production]

[0395] <Support Body>

[0396] An aluminum cylinder with a diameter of 30 mm and a length of 260.5 mm is used as the support (cylindrical support).

[0397] <Conductive Layer>

[0398] Anatase titanium oxide with an average primary particle size of 200 nm was used as the matrix. In addition, a titanium-niobium sulfuric acid solution containing 33.7 parts of titanium (calculated as TiO2) and 2.9 parts of niobium (calculated as Nb2O5) was prepared.

[0399] 100 parts of the matrix were dispersed in pure water to provide a suspension of 1,000 parts, and the suspension was heated to 60°C. A titanium-niobium sulfuric acid solution and 10 mol / L sodium hydroxide were added dropwise to the suspension over 3 hours to adjust the pH to 2–3. After the complete addition of the solution, the pH was adjusted to near the neutral zone, and a polyacrylamide-based flocculant was added to the mixture to allow the solids to settle. The supernatant was removed, and the residue was filtered, washed, and then dried at 110°C. This yielded an intermediate containing 0.1% by mass of organic matter derived from the flocculant (C). The intermediate was calcined in nitrogen at 750°C for 1 hour, and then calcined in air at 450°C to produce titanium oxide particles. The average particle size (average primary particle size) of the obtained titanium oxide particles, determined by a particle size measurement method involving scanning electron microscopy, was 220 nm.

[0400] Subsequently, 50 parts of phenolic resin, used as a binder, were dissolved in 35 parts of 1-methoxy-2-propanol, used as a solvent, to provide a solution. A commercially available product (product name: PLYOPHEN J-325, manufactured by DIC Corporation, resin solids content: 60%, cured density: 1.3 g / cm³) was used as a mixture of monomers and oligomers of the phenolic resin. 3 It is used as a phenolic resin.

[0401] Sixty parts of titanium dioxide particles were added to the above solution. The mixture was fed into a vertical sand mill using 120 parts of glass beads with an average particle size of 1.0 mm as the dispersion medium, and dispersed for 4 hours at a dispersion temperature of 23±3℃ and a rotation speed of 1,500 rpm (circumferential speed: 5.5 m / s) to provide the dispersion. The glass beads were removed from the dispersion using a sieve.

[0402] Next, prepare the following materials.

[0403] • 0.01 parts of silicone oil (product name: SH28 PAINT ADDITIVE, manufactured by Dow Corning Toray Co., Ltd.) used as a leveling agent.

[0404] • Silicone resin particles used as a surface roughening material (product name: KMP-590, manufactured by Shin-Etsu Chemical Co., Ltd., average particle size: 2μm, density: 1.3g / cm³) 3 8 copies

[0405] These materials were added to the dispersion after the glass beads were removed, and the mixture was stirred and filtered under pressure using PTFE filter paper (product name: PF060, manufactured by Advantec Toyo Kaisha, Ltd.) to prepare a coating solution for the conductive layer.

[0406] The conductive layer thus prepared is applied to the support by dip coating to form a coating film, and the coating film is heated at 150°C for 20 minutes to cure, thereby forming a conductive layer with a thickness of 25 μm.

[0407] <Undercoat>

[0408] The primer coating is applied to the conductive layer by dip coating to form a coating film, and the coating film is dried by heating at 100°C for 10 minutes to form a primer coating with a thickness of 2 μm.

[0409] <charge generation layer>

[0410] The charge generation layer is applied to the base layer by dip coating with coating liquid 1 to form a coating film, and the coating film is dried by heating at 100°C for 10 minutes to form a charge generation layer with a thickness of 0.2 μm.

[0411] <charge transport layer>

[0412] The charge transport layer is applied to the charge generation layer by dip coating with coating liquid 1 to form a coating film, and the coating film is dried by heating at 120°C for 30 minutes to form a charge transport layer with a thickness of 14 μm.

[0413] Thus, an electrophotographic photosensitive component 1 is obtained.

[0414] [Rating 1]

[0415] For the electrophotographic photosensitive component 1 obtained in Electrophotographic Photosensitive Component Production Example 1, the following measurements and analyses are performed to calculate the constants A, "m" and τ.

[0416] Prepare Figure 5The measuring device shown in the figure. A transparent glass 201 with transparent electrodes vapor-deposited on its surface is prepared, and an electrophotographic photosensitive element 202 is disposed thereon to achieve conductivity. The electrophotographic photosensitive element 202 is grounded via its support. The electrophotographic photosensitive element is connected to a power supply 203 via the transparent glass 201 and wires, and a voltage can be applied to the electrophotographic photosensitive element 202 by issuing commands from a control computer 204. In addition, the electrophotographic photosensitive element 202 is also connected to a high-speed potentiometer 205 via the transparent glass 201 and wires, and the potential of the surface of the electrophotographic photosensitive element 202 in contact with the transparent glass 201 can be read in real time. The surface of the electrophotographic photosensitive element 202 can be illuminated from the back side of the transparent glass 201 by means of a light source 206. The charged electrophotographic photosensitive element 202 is illuminated by light from the light source 206, and the change in potential at this time can be read by the high-speed potentiometer 205.

[0417] By using Figure 5 The characteristics of the electrophotographic photosensitive element in the measuring device shown are specified under the following conditions:

[0418] (1) Charge the electrophotographic photosensitive element 202 for 0.005 seconds;

[0419] (2) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (1) is V d [V] indicates;

[0420] (3) 0.18 seconds after the start of charging in (1), the electrophotographic photosensitive element 202 is charged for 0.005 seconds so that the absolute value of the charged potential becomes V again. d ;

[0421] (4) 0.02 seconds after the start of charging in (3), use light source 206 with a wavelength of 805 nm and a light intensity of 0.5 μJ / cm². 2 Expose the light to the target area;

[0422] (5) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (3) is defined as the residual potential V. r [V];

[0423] (6) When making V d While varying the voltage from 100V to 1,000V in 50V increments, processes (1) to (5) are repeated to measure the voltage corresponding to V. d V values r ;and

[0424] (7) The V obtained by plotting in (6) d and V rThe obtained graph is approximated by the following equation (E-1) to determine the constants A, "m", and τ in the following equation (E-1), where the horizontal axis represents V. d And the vertical axis represents V r .

[0425]

[0426] In the evaluation of the characteristics of electrophotographic photosensitive components in existing technologies, electrophotographic equipment is often modified to measure the charged potential of the electrophotographic photosensitive component. In these cases, the exposure position of the electrophotographic photosensitive component differs from its potential measurement position. Therefore, a potential decrease occurs due to dark decay before the exposed portion reaches the potential measurement position from the exposure position. Thus, the residual potential V is measured as an absolute value less than the potential at the instant of exposure. r At this point, as the processing speed of the electrophotographic device increases, the time difference becomes smaller and the dark attenuation also decreases. The method for evaluating the characteristics of the electrophotographic photosensitive component in this embodiment can measure the charged potential of the electrophotographic photosensitive component without any time difference, and therefore can be considered a device capable of measurement under the most stringent conditions that maximize the processing speed of the electrophotographic device.

[0427] [Example 2 of Electrophotographic Photosensitive Component Production]

[0428] Except for forming an undercoat layer on the support body without providing a conductive layer in Example 1 of Electrophotographic Photosensitive Component Production, the electrophotographic photosensitive component is produced in the same manner as in Example 1 of Electrophotographic Photosensitive Component Production.

[0429] [Example 3 of Electrophotographic Photosensitive Component Production]

[0430] In Example 1 of Electrophotographic Photosensitive Component Production, a protective layer coating liquid 1 is applied to the charge transport layer of Example 1 of Electrophotographic Photosensitive Component Production by dip coating, thereby forming a coating film under the following conditions. Except as described above, the Electrophotographic Photosensitive Component is produced in the same manner as in Example 1 of Electrophotographic Photosensitive Component Production.

[0431] A protective layer was applied to the charge transport layer using coating solution 1 via dip coating to form a coating film, and the resulting coating film was dried at 35°C for 4 minutes. Subsequently, under a nitrogen atmosphere, with the distance between the support (the irradiated object) and the electron beam irradiation window set to 25 mm and the support (the irradiated object) rotated at 300 rpm, the coating film was irradiated with an electron beam for 4.8 seconds at an accelerating voltage of 57 kV and a beam current of 5.3 mA. The absorbed dose of the electron beam was measured to be 20 kGy at this time. Subsequently, under a nitrogen atmosphere, the temperature was increased from 25°C to 137°C over 10 seconds to heat the coating film. The oxygen concentration during the time period from electron beam irradiation to the subsequent heat treatment was below 10 ppm. Next, the coating film was allowed to cool naturally in air until its temperature reached 25°C, and then heat-treated for 10 minutes at a temperature of 100°C. This resulted in a protective layer with a thickness of 3.0 μm.

[0432] [Examples of Electrophotographic Photosensitive Component Production 3-29]

[0433] Compared to Example 1 of Electrophotographic Photosensitive Component Production, the presence or absence of a conductive layer, the type and thickness of each coating liquid used to form the base layer, charge generation layer, and charge transport layer, as well as the presence or absence and thickness of the protective layer, are changed as shown in Table 1. Except for the foregoing, the electrophotographic photosensitive component is produced in the same manner as in Example 1 of Electrophotographic Photosensitive Component Production.

[0434]

[0435] [Example 1]

[0436] Electrophotographic photosensitive element 1 is installed into an electrophotographic device X obtained by modifying a laser beam printer (product name: HP LaserJet Enterprise M612dn) manufactured by Hewlett-Packard Company, and the resulting object is used as electrophotographic device 1.

[0437] Electrophotographic apparatus X is capable of measuring the charge potential of an electrophotographic photosensitive component using a surface potentiometer. Furthermore, electrophotographic apparatus X is equipped with a voltage application unit, a charge movement detection unit, and a charge potential control unit. The voltage application unit is configured to apply a DC voltage to a charging roller to induce discharge from the charging roller to the electrophotographic photosensitive component 1. The charge movement detection unit is configured to detect the amount of charge movement per unit time caused by the discharge from the charging roller to the electrophotographic photosensitive component. Furthermore, the charge potential control unit calculates the discharge initiation voltage V based on the detected charge movement per unit time. thAnd the slope of charge movement relative to DC voltage. Based on the calculation results, the charged potential control unit further calculates the control target value V relative to the charged potential. td Control DC voltage V DC1 The results are then fed back to the voltage application unit.

[0438] The minimum detectable charge movement I per unit time in electrophotographic device X min Measurements are taken using methods described below.

[0439] The following describes I min The specific process of the measurement method.

[0440] First, the charge movement detection unit is connected between contact point A between the processing cartridge and the charging roller, and the high-voltage contact point B (the contact point used to supply voltage from the high-voltage power supply built into the body of the electrophotographic device X) between the processing cartridge and the main body of the electrophotographic device X. Then, insulation is established between contact point A and the high-voltage contact point B to allow current to flow through the charge movement detection unit. Thus, the amount of current flowing from the charging roller to the electrophotographic photosensitive element can be measured.

[0441] Next, solid white images were printed on five sheets of paper, and the current values ​​during image formation, excluding the intervals of 3 seconds clockwise and 1 second counterclockwise, were measured using a charge transfer detection unit. The current values ​​were sampled every 10 ms, and the maximum and minimum current values ​​within the aforementioned intervals were determined.

[0442] The difference between the aforementioned maximum and minimum current values ​​is calculated under each of the following two environments: a high-temperature, high-humidity environment of 32.5°C and 80% humidity, and a low-temperature, low-humidity environment of 15°C and 10% humidity. The larger of the current differences obtained under the two environments is defined as I. min .

[0443] The minimum detectable charge movement I per unit time in electrophotographic device X min Using the above method for measurement, the result is obtained as I. min The maximum and minimum current values ​​obtained under high temperature and high humidity conditions are 1.2 μA, and the maximum and minimum current values ​​obtained under low temperature and low humidity conditions are 1.4 μA.

[0444] Next, the measured I is obtained through the following method. min To calculate the absolute value V of the minimum detectable potential difference. min The following describes V. min The specific process of the measurement method.

[0445] First, insulate the high-voltage contact point B of the main body of the aforementioned electrophotographic device X. Prepare an external power supply (TREK615-3-L) and connect the external power supply and contact point A via a charge movement detection unit. Link the external power supply to the motor used to drive the processing box, thereby applying voltage while driving the motor and stopping the application of voltage while stopping the motor.

[0446] Next, solid white images were printed on five sheets of paper, and the current value during image formation was measured, excluding the intervals of 3 seconds clockwise and 1 second counterclockwise. The applied voltage V from the external power supply was then applied. a The voltage is set to -800V, the current value is sampled every 10ms, and the average current value I within the above interval is calculated. a Change the external power supply setting to -1,200V (V). b And similarly, calculate the average value I of the current value in the above interval. b .

[0447] The electrophotographic device 1 was measured under the above conditions, and the results are as follows: I a =20.9μA and I b =65.7μA.

[0448] Next, find the result through V a V b I a and I b The slope of the straight line obtained by plotting voltage relative to current, and the calculation of V min .

[0449] V min =|I min ×(V a -V b ) / (I a -I b )|

[0450] =|-1.4×400 / 44.8|

[0451] =12.5V

[0452] Therefore, the absolute value V of the minimum detectable potential difference can be calculated. min It is 12.5V.

[0453] [Rating 2]

[0454] Based on the above formula (E-2) for calculating V1 and formula (E-3) for calculating V2, the characteristics (A, "m" and τ) of the electrophotographic photosensitive element 1 analyzed in [Evaluation 1] and the aforementioned calculated V minThe values ​​were used to estimate V1 and V2. The results are shown in Table 2, namely, V1 = 16.8 (V) and V2 = 8,105 (V).

[0455] Therefore, it was found that the electronic photographic device 1 satisfies the following inequality (E-4).

[0456] 100V1 <V2-V1(E-4)

[0457] In evaluation 2, cases that satisfy inequality (E-4) are classified as level A, and cases that do not satisfy the inequality are classified as level B.

[0458] [Rating 3]

[0459] Based on the above formula (E-2) for calculating V1 and formula (E-11) for calculating V2′, the characteristics (A, "m" and τ) of the electrophotographic photosensitive element 1 analyzed in [Evaluation 1] and the aforementioned calculated V min The values ​​were used to estimate V1 and V2′. The results are shown in Table 2, namely, V1 = 16.8 (V) and V2′ = 5,237 (V).

[0460] Therefore, it is found that the electronic photographic device 1 satisfies the following inequality (E-12).

[0461] 100V1 <V2′-V1(E-12)

[0462] In evaluation 3, cases that satisfy inequality (E-12) are classified as level A, and cases that do not satisfy the inequality are classified as level B.

[0463] [Rating 4]

[0464] In the electrophotographic device 1, the charged potential is controlled based on the following control method 1. The target value for controlling the charged potential is set to V. td = -500V, and the absolute value V of the charged potential obtained after using control. d1 The control accuracy Acc1 is calculated based on the following formula (E-20).

[0465] Acc1 = 100 × |V d1 -500| / 500(E-20)

[0466] [Control Method 1]

[0467] (1) Start the program (sequence) with the charged potential at 0V.

[0468] (2) Drive the main motor.

[0469] (3) Apply developing bias voltage.

[0470] (4) Exposure.

[0471] (5) Apply VA = -800 (V) to the charging roller and average the current value of the electrophotographic photosensitive element as it rotates one revolution.

[0472] (6) Apply VB = -3,000 (V) to the charging roller and average the current value for one revolution of the electrophotographic photosensitive element.

[0473] (7) Approximate the relationship between the applied voltage and current at points (5) and (6) using a straight line to calculate the discharge initiation voltage V. th .

[0474] (8) The discharge start voltage V calculated in (7) is obtained by using the above formula (E-15). th and the target value V of the charged potential td = -500V to calculate the control DC voltage V DC1 .

[0475] (9) Stop the main motor, development bias and exposure.

[0476] (10) End the program.

[0477] The absolute value of the charged potential in the above control (5) is V dm =269 (V), and the absolute value of the charged potential in the above control (6) is V. dM = 2,469 (V). Meanwhile, according to [Evaluation 2] and [Evaluation 3], the V1, V2, and V2′ of the electrophotographic photosensitive element 1 are V1 = 16.8 (V), V2 = 8,105 (V), and V2′ = 5,237 (V), respectively. Therefore, it is found that the electrophotographic device 1 satisfies the following inequalities (E-18) and (E-19).

[0478] V1 <V dm <V dM ≤V2 (E-18)

[0479] V1 <V dm <V dM ≤V2′ (E-19)

[0480] In evaluation 4, for each of inequalities (E-18) and (E-19), the case where the inequality is satisfied is classified as level A, and the case where the inequality is not satisfied is classified as level B.

[0481] The estimated discharge start voltage V calculated from the values ​​obtained in the above controls (5) and (6) th The value is -527V. Therefore, the control DC voltage V obtained in the above control (8) is...DC1 The value is -527V + (-500V) = -1,027V. The control DC voltage V obtained from this is used. DC1 The photosensitive element 1 in the electrophotographic device 1 is charged, and as a result, a charged potential of -496V is obtained.

[0482] Therefore, Acc1 is as follows: Acc1 = 100 × |496-500| / 500 = 0.8 (%).

[0483] When the above control method 1 is applied to the electronic photographic device 1, the control time required is 1.5 seconds.

[0484] [Example 2]

[0485] Except that, in Example 1, control method 2 is used instead of control method 1 as the control method used in evaluation 4 to control the charged potential, control is performed in the same manner as in Example 1.

[0486] [Control Method 2]

[0487] (1) Start the program with the charged potential at 0V.

[0488] (2) Drive the main motor.

[0489] (3) Apply developing bias voltage.

[0490] (4) Exposure.

[0491] (5) Apply VA = -800 (V) to the charging roller and average the current value of the electrophotographic photosensitive element as it rotates one revolution.

[0492] (6) Apply VC = -1,350 (V) to the charging roller and average the current value of the electrophotographic photosensitive element as it rotates one revolution.

[0493] (7) Approximate the relationship between the applied voltage and current at points (5) and (6) using a straight line to calculate the discharge initiation voltage V. th .

[0494] (8) The discharge start voltage V calculated in (7) is obtained by using the above formula (E-15). th and the target value V of the charged potential td = -500V to calculate the control DC voltage V DC2 .

[0495] (9) Stop the main motor, development bias and exposure.

[0496] (10) End the program.

[0497] The absolute value of the charged potential in the above control (5) is V dm =269 (V), and the absolute value of the charged potential in the above control (6) is V. dM = 819 (V). Meanwhile, according to [Evaluation 2] and [Evaluation 3], the V1, V2, and V2′ of the electrophotographic photosensitive element 1 are V1 = 16.8 (V), V2 = 8,105 (V), and V2′ = 5,237 (V), respectively. Therefore, it is found that the electrophotographic device 1 satisfies the above-mentioned inequalities (E-18) and (E-19).

[0498] The estimated discharge start voltage V calculated from the values ​​obtained in the above controls (5) and (6) th The value is -528V. Therefore, the control DC voltage V obtained in the above control (8) is... DC1 The value is -528V + (-500V) = -1,028V. The control DC voltage V obtained from this is used. DC1 The photosensitive element 1 in the electrophotographic device 1 is charged, and as a result, a charged potential of -497V is obtained.

[0499] Therefore, Acc1 is as follows: Acc1 = 100 × |497-500| / 500 = 0.6 (%).

[0500] When the above control method 2 is applied to the electronic photographic equipment 1, the control time required is 1.5 seconds.

[0501] [Example 3]

[0502] Except that, in Example 1, control method 3 is used instead of control method 1 as the control method used in evaluation 4 to control the charged potential, control is performed in the same manner as in Example 1.

[0503] [Control Method 3]

[0504] (1) Start the program with the charged potential at 0V.

[0505] (2) Drive the main motor.

[0506] (3) Apply developing bias voltage.

[0507] (4) Exposure.

[0508] (5) Apply VA = -800 (V) to the charging roller and average the current value for one revolution of the drum.

[0509] (6) Apply VC = -1,350 (V) to the charging roller and average the current value for one revolution of the drum.

[0510] (7) Apply VE = -1,800 (V) to the charging roller and average the current value for one revolution of the drum.

[0511] (8) The relationship between the applied voltage and current at the three points (5), (6) and (7) is approximated by a quadratic function to calculate the discharge initiation voltage V. th .

[0512] (9) The discharge start voltage V calculated in (8) is obtained by using the above formula (E-15). th and the target value V of the charged potential td = -500V to calculate the control DC voltage V DC3 .

[0513] (10) Stop the main motor, development bias and exposure.

[0514] (11) End the program.

[0515] The absolute value of the charged potential in the above control (5) is V dm =269 (V), and the absolute value of the charged potential in the above control (7) is V. dM = 1,269 (V). Meanwhile, according to [Evaluation 2] and [Evaluation 3], the V1, V2, and V2′ of the electrophotographic photosensitive element 1 are V1 = 16.8 (V), V2 = 8,105 (V), and V2′ = 5,237 (V), respectively. Therefore, it is found that Example 3 satisfies the above-mentioned inequalities (E-18) and (E-19).

[0516] The estimated discharge start voltage V is calculated from the values ​​obtained in the above controls (5), (6) and (7). th The value is -528V. Therefore, the control DC voltage V obtained in the above control (8) is... DC1 The value is -528V + (-500V) = -1,028V. The control DC voltage V obtained from this is used. DC1 The photosensitive element 1 in the electrophotographic device 1 is charged, and as a result, a charged potential of -497V is obtained.

[0517] Therefore, Acc1 is as follows: Acc1 = 100 × |497-500| / 500 = 0.6 (%).

[0518] The above control method 3 was applied to the electrophotographic photosensitive component 1, and the control time required was 1.8 seconds.

[0519] [Examples 4-30 and Comparative Examples 1-11]

[0520] Except for changing the type of electrophotographic photosensitive component installed in the electrophotographic device X and the control method for controlling the charged potential as shown in Table 2, the evaluation was conducted in the same manner as in Example 1.

[0521]

[0522]

[0523] While the invention has been described with reference to exemplary embodiments, it should be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the appended claims is to be interpreted in the broadest possible sense to cover all such modifications and equivalent structures and functions.

Claims

1. An electronic photographic device, characterized in that, It comprises: an electrophotographic photoreceptor; a voltage applying unit configured to cause discharge from a conductive member to the electrophotographic photoreceptor; a charge movement amount detecting unit configured to detect an amount of charge movement per unit time caused by the discharge from the conductive member to the electrophotographic photoreceptor; and a charging potential control unit configured to control a charging potential of the electrophotographic photoreceptor, wherein the electrophotographic photoreceptor comprises a support, an undercoat layer, a charge generating layer and a charge transport layer in this order, wherein the undercoat layer comprises a polyamide resin and metal oxide particles, wherein the metal oxide particles are titanium oxide particles, wherein the titanium oxide particles have an average primary particle diameter of 10 to 100 nm, wherein the undercoat layer has a thickness of 0.5 to 3.0 µm, wherein the charge generating layer comprises an oxytitanium phthalocyanine pigment or a hydroxygallium phthalocyanine pigment, wherein the oxytitanium phthalocyanine pigment comprises crystal particles having a crystal form that shows peaks at Bragg angles 2θ of 9.8°±0.3° and 27.1°±0.3° in an X-ray diffraction spectrum using CuKα radiation, and has a peak A within a range of 50 to 150 nm in a crystal particle size distribution measured by small-angle X-ray scattering, and wherein the half width of the peak A is 100 nm or less, wherein the hydroxygallium phthalocyanine pigment comprises crystal particles having a crystal form that shows peaks at Bragg angles 2θ of 7.4°±0.3° and 28.2°±0.3° in an X-ray diffraction spectrum using CuKα radiation, and has a peak B within a range of 20 to 50 nm in a crystal particle size distribution measured by small-angle X-ray scattering, and wherein the half width of the peak B is 50 nm or less, wherein the charge generating layer has a thickness of 0.12 µm or more, wherein the charge transport layer comprises a triarylamine compound represented by the following formula (A1) and a triarylamine compound represented by the following formula (A2) as charge transport substances: ， wherein, when V1 and V2 are determined for the electrophotographic photoreceptor by the following procedures (1) to (8), V1 and V2 satisfy the relationship represented by the following formula (E-4): 100V1 < V2 - V1 (E-4), and wherein the charging potential control unit is configured to control the charging potential of the electrophotographic photoreceptor during image formation based on a relationship between DC voltages at at least two points selected from a range where the absolute value of the DC voltage applied by the voltage applying unit is 700 V or more and the charge movement amounts under the DC voltages at said at least two points: (1) charging the electrophotographic photoreceptor for 0.005 seconds; (2) The absolute value of the charged potential obtained by measurement is represented by V d at 0.06 seconds after the start of charging in (1) (3) after 0.18 seconds from the start of charging in (1), charging the electrophotographic photosensitive member for 0.005 seconds to make the absolute value of the charge potential again V d ; (4) 0.02 seconds after the start of charging in (3), use light with a wavelength of 805 nm and a light intensity of 0.5 μJ / cm. 2 Expose the light; (5) The absolute value of the charged potential obtained by measurement 0.06 seconds after the start of charging in (3) is defined as the residual potential V in units of V. r ; (6) When making V d While varying the voltage from 100V to 1,000V in 50V increments, processes (1) to (5) are repeated to measure the voltage corresponding to V. d V values r ; (7) The V obtained by plotting in (6) d and V r The obtained graph is approximated by the following equation (E-1) to determine the constants A, "m", and τ in the following equation (E-1), where the horizontal axis represents V. d And the vertical axis represents V r , ;and (8) voltages calculated by the following formulas (E-2) and (E-3) using the constants A, "m" and τ determined in (7) are defined as V1 and V2, respectively: In equation (E-2), V min This represents the value determined by the accuracy of the charge movement detection unit. 。 2. The electrophotographic apparatus according to claim 1, wherein when a voltage calculated from the constants A, "m" and τ by the following formula (E-12) is represented by V2', V1 and V2' satisfy the relationship of the following formula (E-13): 100V1 < V2' - V1 (E-13).

3. The electrophotographic device according to claim 1 or 2, The voltage application unit is a charging unit configured to charge the electrophotographic photosensitive element, and The conductive component mentioned above is a charging component.

4. The electrophotographic device according to claim 3, wherein the charging component is a charging roller.

5. The electrophotographic device according to claim 1 or 2, The voltage application unit is configured to transfer toner from the surface of the electrophotographic photosensitive component to a transfer material, and The conductive component mentioned above is a transfer component.

6. The electrophotographic apparatus according to claim 1 or 2, wherein the charged potential control unit is configured to control the DC voltage applied during image formation by means of the relationship between the DC voltage at the at least two points and the amount of charge movement under the DC voltage at the at least two points.

7. The electrophotographic apparatus according to claim 1 or 2, wherein the charged potential control unit is configured to: approximate the relationship between the DC voltage at point "n", selected from the range where the absolute value of the DC voltage applied by the voltage application unit is 700V or more, and the amount of charge movement under the DC voltage at point "n", by a function with "n" or less of a degree of freedom, where "n" represents an integer greater than or equal to 2; and control the charged potential of the electrophotographic photosensitive element during image formation by using the function as a calibration curve.

8. The electrophotographic device according to claim 7, wherein the function is a linear function.

9. The electrophotographic apparatus according to claim 1 or 2, wherein the constant A is 15 or less.

10. The electrophotographic apparatus according to claim 1 or 2, wherein the constant "m" is less than or equal to 0.

05.

11. The electrophotographic apparatus according to claim 1 or 2, wherein the absolute value of the constant τ is 4,000 or more.

Images