JP2012220829A - Degradation determining device for electrophotographic photoreceptor, and image forming apparatus using the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a degradation determining device capable of determining a lifetime (exchange stage) of an electrophotographic photoreceptor before quality of an output image is degraded, and an image forming apparatus using the device.SOLUTION: A degradation determining device 2 of an electrophotographic photoreceptor 1 having, on an outer peripheral part, a layer 14 which contains a charge transporting substance for emitting fluorescence upon receiving and exciting UV light of a predetermined wavelength comprises: a light irradiating part 2A for irradiating a charge transporting substance containing layer 14 with UV light Le which includes the predetermined wavelength and which generates the fluorescence by exciting the charge transporting substance of the photoreceptor 1 that is a determination object; a fluorescence detecting part 2B for receiving fluorescence Lf emitted by the charge transporting substance and measuring the fluorescence intensity; and an evaluating part 2C for determining a degree of degradation of the charge transporting substance containing layer 14 by comparing the fluorescence intensity measured by the fluorescence detecting part 2B and an initial fluorescence intensity which is preliminary measured when the charge transporting substance containing layer 14 of the photoreceptor 1 is in an unused state.

Description

  The present invention relates to an electrophotographic photoreceptor deterioration determination apparatus and an image forming apparatus including the apparatus.

  2. Description of the Related Art An electrophotographic image forming apparatus (also referred to as “electrophotographic apparatus”) that forms an image using electrophotographic technology is widely used in copying machines, printers, facsimile machines, and the like. As an electrophotographic photoreceptor mounted in this image forming apparatus, a so-called organic photoreceptor (OPC photoreceptor) using an organic photoconductive substance has been put into practical use. Hereinafter, the “electrophotographic photosensitive member” may be abbreviated as “photosensitive member”.

At the time of image formation, the surface of the photoconductor is generally charged by dispersing ions generated by corona discharge on the surface of the photoconductor. At this time, ozone and NOx are inevitably generated from oxygen and nitrogen in the air during corona discharge. Further, NOx may be generated in the installation environment of the image forming apparatus. For example, an example in which oil or a gas stove is used in winter in a small private store or office can be given.
In such a case, the image forming apparatus is exposed to an atmosphere containing ozone and NOx generated by itself and NOx generated in the installation environment.

  Although the OPC photoreceptor is highly productive and inexpensive, an oxidizing gas such as ozone or an acidic gas such as NOx tends to cause deterioration in electrophotographic characteristics such as a decrease in charging potential, sensitivity fluctuation, and increase in residual potential. Further, an image forming apparatus using reversal development causes a decrease in image density. These causes are thought to be caused by the progress of a chemical reaction in which the charge transport material is hydrolyzed by an oxidizing gas and an acidic gas to produce aldehydes.

  In order to avoid such problems, it is known to add an antioxidant to the OPC photoreceptor. For example, a method of adding an antioxidant such as 2,6-di-t-butyl-p-cresol (BHT) to the charge transport layer (see, for example, Patent Document 1), an antioxidant such as hindered amines to the photosensitive layer There is known a method of adding (see, for example, Patent Document 2). However, since the antioxidant acts as a charge trap, when added in a large amount, a new problem of causing deterioration of electrical characteristics arises.

On the other hand, as a method for determining the life of a photoconductor, a method has been proposed in which a surface potential meter is installed in the image forming apparatus and the life of the photoconductor is determined from a change in the surface potential of the photoconductor (for example, Patent Document 3 and 4). Furthermore, a method has also been proposed in which a thermometer is installed in the image forming apparatus, and the lifetime of the photoconductor is determined in consideration of the temperature dependence of the surface potential (see, for example, Patent Document 5).
In general, charge transport materials used in electrophotographic photoreceptors are similar in chemical structure to fluorescent dyes, and are known to emit fluorescence when excited by ultraviolet light. For example, in the case of amine compounds widely used in this field, it is known that fluorescence having a peak around 430 nm or around 530 nm is observed (for example, see Patent Document 6).

JP-A-61-156052 Japanese Unexamined Patent Publication No. 63-018355 JP-A-9-190120 JP 2006-139272 A JP 2010-128012 A JP 2010-271650 A

In the conventional method proposed as described above, a change in potential due to deterioration of the photoconductor is detected by a surface potentiometer, and if it is determined that the lifetime of the photoconductor has been reached, replacement of the photoconductor is urged.
However, since the change in the surface potential substantially corresponds to the deterioration of the output image, when it can be determined that the photoreceptor is deteriorated by the surface potential, there is already a problem on the image. Therefore, the response of exchanging the photoconductor after a problem has occurred in the image hinders the user's work.

  The present invention has been made in view of the above problems, and a deterioration determination device capable of determining the life (replacement time) of an electrophotographic photosensitive member before the quality of an output image is deteriorated, and an image forming apparatus including the deterioration determination device. The purpose is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have decomposed the charge transport material from the intensity of the fluorescence emitted from the charge transport material of the electrophotographic photoreceptor similar in chemical structure to the fluorescent dye. The present inventors have found that the degree of disappearance can be estimated and that the lifetime of the photoreceptor can be determined, and the present invention has been completed.

Thus, according to the present invention, there is provided an apparatus for determining deterioration of an electrophotographic photoreceptor having a layer containing a charge transport material that receives and excites ultraviolet light having a predetermined wavelength and emits fluorescence to emit fluorescence,
A light irradiation unit that irradiates the charge transport material-containing layer with ultraviolet light having the predetermined wavelength that excites the charge transport material of the electrophotographic photosensitive member to be determined to generate fluorescence;
A fluorescence detector that receives fluorescence emitted by the charge transport material and measures fluorescence intensity;
By comparing the fluorescence intensity measured by the fluorescence detector with the initial fluorescence intensity measured in advance when the charge transport material-containing layer of the electrophotographic photoreceptor is unused, the charge transport material-containing layer An electrophotographic photosensitive member deterioration determination apparatus including an evaluation unit that determines the degree of deterioration of the image is provided.

  According to the degradation determination apparatus of the present invention, since the fluorescent property of the charge transport material in the charge transport material-containing layer of the electrophotographic photoreceptor is used, the sign of the photoreceptor degradation is detected before the change of the potential property. be able to. As a result, since the electrophotographic photosensitive member can be replaced before the problem of the formed image occurs, it can be avoided that the work of the user is hindered.

1 is a schematic configuration diagram illustrating an embodiment of an image forming apparatus including a deterioration determination device of the present invention. It is a schematic block diagram which shows one Embodiment of the deterioration determination apparatus of this invention. FIG. 2 is a block diagram of an image forming apparatus including the deterioration determination device in FIG. 1. FIG. 2 is a partially enlarged cross-sectional view showing a laminated structure of an electrophotographic photosensitive member provided in the image forming apparatus of FIG. 1. It is a graph which shows the result of having measured the fluorescence spectrum of the fluorescence which generate | occur | produced by irradiating 370 nm excitation light to a compound (1) with the spectrophotometer. It is a graph which shows the result of having measured the fluorescence spectrum of the fluorescence which generate | occur | produced by irradiating 370 nm excitation light to a compound (3) with the spectrophotometer.

  As described above, the electrophotographic photoconductor degradation determination apparatus of the present invention includes the light irradiation unit, the fluorescence detection unit, and the evaluation unit, and the charge transport material in the charge transport material-containing layer of the electrophotographic photoconductor is Degradation of the electrophotographic photosensitive member can be determined using the fluorescence characteristics possessed. Specifically, since the charge transport material does not emit fluorescence when decomposed, the deterioration degree of the charge transport material-containing layer can be determined by observing the change in the fluorescence intensity of the charge transport material-containing layer.

The light irradiation unit has a function of irradiating the charge transport material-containing layer with ultraviolet light having a predetermined wavelength that excites the charge transport material of the electrophotographic photosensitive member to be determined to generate fluorescence.
The fluorescence detection unit has a function of receiving fluorescence emitted from the charge transport material and measuring fluorescence intensity.
The evaluation unit compares the fluorescence intensity measured by the fluorescence detection unit with the initial fluorescence intensity measured in advance when the charge transport material-containing layer of the electrophotographic photosensitive member is unused. It has a function of determining the degree of deterioration of the charge transport material-containing layer.

  The electrophotographic image forming apparatus that can be provided with the degradation determination apparatus of the present invention is not particularly limited, and includes, for example, an electrophotographic copying machine, a printer, a facsimile machine, or a complex machine thereof.

The electrophotographic photosensitive member deterioration determination apparatus may be configured as in the following (1) to (4), and these may be combined as appropriate.
(1) When the evaluation unit determines that Dm <Db × α (α is a coefficient smaller than 1) when the initial fluorescence intensity is the reference value D and the fluorescence intensity is the measurement value Dm, a warning signal is output. It is configured to output.
In this way, it is possible to actively inform the user of the image forming apparatus provided with this deterioration determining device about the replacement time of the electrophotographic photosensitive member before the quality of the formed image is lowered.

(2) The light irradiation unit is an ultraviolet light emitting diode, and the fluorescence detection unit is a silicon photodiode.
In this way, since a large-scale analysis device is not necessary, a deterioration determination device can be manufactured at low cost. In addition, since the light irradiation unit is configured using an ultraviolet light emitting diode without using a lamp, a deterioration determination device that is resistant to dropping and impact can be obtained.

(3) The fluorescence detection unit may have a filter on the light receiving surface.
If it does in this way, the direct light and reflected light from a light irradiation part will be cut reliably by a filter, and the entrance to a fluorescence detection part will be blocked | prevented. As a result, the fluorescence detection unit can receive only the fluorescence emitted by excitation of the charge transport material.
Therefore, according to the configuration (3), it is possible to perform highly accurate deterioration determination, and it is easy to arrange the light irradiation unit and the fluorescence detection unit for performing highly accurate deterioration determination.
If the emission wavelength of the light irradiator and the sensitivity wavelength of the fluorescence detector differ to some extent, for example, if there is a difference of 100 nm or more, direct light and reflected light from the light irradiator are mixed with the fluorescence to the fluorescence detector. Even if it is incident, only the fluorescence can be detected by the fluorescence detection unit. Therefore, in the present invention, the filter is not an essential requirement.
In addition, the sensitivity of the silicon photodiode in the fluorescence detector is in the entire visible light region, and the sensitivity in the ultraviolet light region is low. Therefore, it is possible to detect fluorescence even when directly receiving light without a filter. It is preferable to provide a band-pass filter in order to prevent malfunction due to wavelength components and short wavelength components of infrared light used for image exposure.

(4) The light irradiation unit is configured to be able to irradiate light having an emission wavelength of 360 to 460 nm, and the fluorescence detection unit is configured to be able to detect light having a wavelength of 510 to 580 nm.
In this way, since the fluorescence wavelength of the fluorescence emitted by the charge transport material matches the characteristics of the fluorescence detection unit, it is possible to suppress determination mistakes and perform deterioration determination with higher accuracy.

According to another aspect of the present invention, an electrophotographic photosensitive member having a surface on which an electrostatic latent image is formed, the deterioration determining device, a charging unit for charging the surface of the photosensitive member, and the photosensitive member An exposure unit that forms an electrostatic latent image on the surface of the photosensitive member, a developing unit that supplies toner to the electrostatic latent image on the surface of the photosensitive member to form a toner image, and a toner image on the surface of the photosensitive member. An image forming apparatus is provided that includes a transfer unit that transfers the toner image, a cleaning unit that cleans the surface of the photoconductor, and a fixing unit that fixes a toner image on a recording medium.
According to this image forming apparatus, it is possible to prevent defects in the formed image due to deterioration of the electrophotographic photosensitive member.

  This image forming apparatus may be configured as follows (A) to (C).

(A) The evaluation unit of the degradation determination apparatus, when the initial fluorescence intensity is a reference value D and the fluorescence intensity is a measurement value Dm, Dm <Db × α (α is a coefficient smaller than 1) and When judged, it is configured to output a warning signal,
The image forming apparatus further includes a control unit to which the warning signal is input, a display unit and a drive unit electrically connected to the control unit,
The control unit has a function of controlling the display unit to display a display prompting replacement of the electrophotographic photosensitive member based on the warning signal.
In this way, the user can know when the electrophotographic photosensitive member should be replaced before a failure occurs, so that an image forming apparatus without interruption of business can be realized.

(B) The control unit is configured to output a stop maintaining signal that does not start the image forming operation based on the warning signal.
In this way, it is possible to avoid wasteful consumption of paper by outputting a defective image.

（式中、
Ａｒ¹及びＡｒ²は、互いに同一または異なって、置換基を有してもよいアリール基または置換基を有してもよい複素環基を表し、
Ａｒ³は、置換基を有してもよいアリール基、置換基を有してもよい複素環基、置換基を有してもよいアラルキル基または置換基を有してもよいアルキル基を表し、
Ａｒ⁴及びＡｒ⁵は、互いに同一または異なって、水素原子、置換基を有してもよいアリール基、置換基を有してもよい複素環基、置換基を有してもよいアラルキル基または置換基を有してもよいアルキル基を表し、ただし、Ａｒ⁴及びＡｒ⁵が共に水素原子ではなく、Ａｒ⁴及びＡｒ⁵は、原子または原子団を介して互いに結合して環構造を形成してもよく、
ａは、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいジアルキルアミノ基、置換基を有してもよいアリール基、ハロゲン原子または水素原子を表し、
ｍは１〜６の整数であり、ｍが２以上のとき、複数のａは、互いに同一または異なって、互いに結合して環構造を形成してもよく、
Ｒ¹¹は、水素原子、ハロゲン原子または置換基を有してもよいアルキル基を表し、
Ｒ¹²、Ｒ¹³及びＲ¹⁴は、互いに同一または異なって、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよい複素環基または置換基を有してもよいアラルキル基を表し、
ｎは０〜３の整数であり、ｎが２または３のとき、複数のＲ¹²は、互いに同一または異なり、複数のＲ¹³は、互いに同一または異なり、ただし、ｎが０のとき、Ａｒ³は置換基を有してもよい複素環基を表す）
で示される電荷輸送物質を含有する電荷輸送物質含有層を有する。 (C) The electrophotographic photosensitive member has the following general formula (I):

(Where
Ar ¹ and Ar ² are the same or different from each other, and each represents an aryl group which may have a substituent or a heterocyclic group which may have a substituent,
Ar ³ represents an aryl group that may have a substituent, a heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or an alkyl group that may have a substituent. ,
Ar ⁴ and Ar ⁵ are the same or different from each other, and are a hydrogen atom, an aryl group that may have a substituent, a heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or Represents an alkyl group which may have a substituent, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms, and Ar ⁴ and Ar ⁵ are bonded to each other via an atom or an atomic group to form a ring structure. You can,
a represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, an aryl group which may have a substituent, a halogen atom; Or a hydrogen atom,
m is an integer of 1 to 6, and when m is 2 or more, a plurality of a may be the same or different from each other and may be bonded to each other to form a ring structure;
R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent,
R ¹² , R ^13, and R ¹⁴ are the same or different from each other, and are a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent, or a complex that may have a substituent. Represents an aralkyl group which may have a ring group or a substituent,
n is an integer of 0 to 3, and when n is 2 or 3, the plurality of R ¹² are the same or different from each other, and the plurality of R ¹³ are the same or different from each other, provided that when n is 0, Ar ³ Represents a heterocyclic group which may have a substituent.
A charge transport material-containing layer containing a charge transport material represented by

The charge transport material represented by the general formula (I) has high charge mobility. Therefore, an image forming apparatus including an electrophotographic photosensitive member having this charge transport material layer (charge transport material-containing layer) can perform high-speed image formation. In other words, it is suitable for determining deterioration of the electrophotographic photosensitive member of the image forming apparatus capable of high-speed image formation.
The compound represented by the general formula (I) can be produced, for example, by the production method described in JP-A No. 2004-151666.
Note that the charge transport material represented by the general formula (I) is an enamine-based compound, and in an atmosphere of an oxidizing gas such as ozone or an acidic gas such as NOx, C is formed between the nitrogen atom and R ¹¹ by hydrolysis. It is presumed that the bond between the carbon atom and the nitrogen atom is broken.

  Hereinafter, specific embodiments of an electrophotographic photosensitive member deterioration determination apparatus and an image forming apparatus including the same will be described in detail.

  FIG. 1 is a schematic configuration diagram showing an embodiment of an image forming apparatus provided with the degradation determination device of the present invention, and FIG. 2 is a schematic configuration diagram showing an embodiment of the degradation determination device of the present invention. FIG. 4 is a block diagram of an image forming apparatus provided with the degradation determination device of FIG. 1, and FIG. 4 is a partially enlarged sectional view showing a laminated structure of electrophotographic photosensitive members provided in the image forming device of FIG.

As shown in FIGS. 1 and 3, the image forming apparatus (laser printer) 100 includes an electrophotographic photosensitive member 1 (hereinafter sometimes abbreviated as “photosensitive member 1”) and a charging unit (charging device) 32. An exposure unit (semiconductor laser) 31, a developing unit (developing unit) 33, a transfer unit (transfer charger) 34, a cleaning unit (cleaner) 36, a neutralizing unit (static eliminating unit) 30, and a transport belt ( (Not shown), a fixing unit (fixing device) 35, a control unit 41, a display unit 42, and a driving unit 43, and further includes the deterioration determination device 2 of the present invention.
In addition, the photoreceptor 1 includes an intermediate layer 12, a charge generation layer 13 containing a charge generation material 13a, and a charge transport layer (charge transport material containing layer) 14 containing a charge transport material 14a on a conductive substrate 11. Laminated in order.
Hereinafter, the deterioration determination device 2, the photoreceptor 1, and the image forming apparatus 100 will be described in detail with reference to FIGS.

<Deterioration determination device>
The degradation determination device 2 includes a light irradiation unit 2A, a fluorescence detection unit 2B, and an evaluation unit 2C.
The light irradiation unit 2A irradiates ultraviolet light (excitation light) having a wavelength that can excite the charge transport material 13a of the photoreceptor 1 to emit fluorescence.
The charge transport material is excited by ultraviolet light having a specific wavelength and emits fluorescence having a specific fluorescence wavelength. That is, the wavelength of the excitation light (excitation wavelength) and the fluorescence wavelength differ depending on the type of charge transport material. Therefore, the light irradiation unit 2A needs to irradiate the ultraviolet light Le having a wavelength capable of exciting the charge transport material 13a used in the photoconductor 1 to be determined to emit the fluorescence Lf.

Furthermore, the excitation wavelength of the excitation light Le is preferably 360 to 460 nm for the following reason.
If the excitation wavelength is less than 360 nm, films such as the charge transport layer 14 and the charge generation layer 13 of the photoreceptor 1 may be deteriorated by the excitation light Le, and the sensitivity of the photoreceptor 1 may be reduced. Depending on the type of the charge transport material 13a used, if the excitation wavelength exceeds 460 nm, the difference between the fluorescence wavelength and the excitation wavelength of the charge transport material 13a may be less than 50 nm, resulting in fluorescence detection. Since it becomes easy for the part 2B to detect the excitation light Le, it becomes difficult to measure the fluorescence intensity by the fluorescence detection part 2B with high accuracy.
Therefore, it is preferable to use what irradiates the excitation light Le of 360-460 nm as the light irradiation part 2A. Accordingly, it is preferable to use a substance that emits fluorescence Lf by excitation light Le of 360 to 460 nm as the charge transport material 13a.
For example, a light emitting element such as a light emitting diode or a semiconductor laser can be used as the light irradiation unit 2A capable of emitting excitation light Le of 360 to 460 nm. Specifically, an ultraviolet light emitting diode can be used as the light emitting diode, and a blue-violet semiconductor laser can be used as the semiconductor laser.

  As described above, it is preferable to use the charge transport material 13a that emits the fluorescence Lf by the excitation light Le of 360 to 460 nm. Further, from the viewpoint of performing highly accurate detection by the fluorescence detection unit 2B, the excitation of 460 nm It is more preferable to emit fluorescence Lf having a fluorescence wavelength (peak wavelength) having a difference of 50 nm or more, preferably 100 nm or more than the wavelength. That is, it is preferable to use the charge transport material 13a that emits fluorescence Lf having a fluorescence wavelength of 510 nm or more, preferably fluorescence Lf having a fluorescence wavelength of 560 nm or more. For example, in the present invention, the charge transport material 13a having a fluorescence wavelength of 360 to 580 nm can be used.

Accordingly, it is preferable to use a fluorescence detection unit 2B that can detect a fluorescence wavelength of 510 nm or more (detection wavelength of 510 nm or more). The upper limit of the detection wavelength of the fluorescence detection unit 2B is not particularly limited, and can be the upper limit (for example, 580 nm) of the fluorescence wavelength of the charge transport material 13a to be used. The upper limit of the detection wavelength of the fluorescence detection unit 2B may exceed 580 nm. However, when the image exposure wavelength is red light, the upper limit of the detection wavelength is preferably 580 nm from the viewpoint of preventing malfunction due to image writing light.
As the fluorescence detection unit 2B, for example, a light receiving element such as a photodiode can be used. Furthermore, the fluorescence detection unit 2B may have a filter (for example, an interference filter) on the light receiving surface in order to detect only light in a specific wavelength region including a predetermined wavelength. When an ultraviolet light emitting diode or a blue-violet semiconductor laser is used as the light irradiation unit 2A, an ultraviolet cut filter is used as the filter.

The light irradiation unit 2A and the fluorescence detection unit 2B are integrated by a housing 3 indicated by a two-dot chain line, and are disposed, for example, near the outer peripheral surface of the photoreceptor 1 between the charge removal unit 30 and the charging unit 32. Yes. Since the toner is removed and the charge is removed at this position, the deterioration of the outer peripheral surface portion of the photosensitive member 1 can be accurately determined, and the housing 3 is fixed because it does not affect image formation during operation. Preferred as position. In addition, although the evaluation part 2C mentioned later may be integrated with 2 A of light irradiation parts and the fluorescence detection part 2B with the housing | casing 3, it may be provided in another position.
For example, the light irradiation unit 2 </ b> A and the fluorescence detection unit 2 </ b> B are arranged side by side in a direction parallel to the rotation axis 44 of the photoreceptor 1.
More preferably, the light irradiation unit 2A and the fluorescence detection unit 2B are provided at one end of the photoreceptor 1 outside the image forming area.

The evaluation unit 2C includes a signal input unit, a storage unit, a calculation unit, and a signal output unit (not shown). Note that the evaluation unit 2 </ b> C may be disposed in the housing 3, or may be disposed at an appropriate location in the apparatus main body of the image forming apparatus 100.
The signal input unit receives a fluorescence intensity signal from the fluorescence detection unit 2B via a signal line and has a function of converting the fluorescence intensity signal into a measured value Dm.
The storage unit has a function of storing the initial fluorescence intensity (reference value Db) of the charge transport material 14a of the charge transport layer 14 when the photoreceptor 1 to be determined is unused. The reference value Db is input to the storage unit, for example, when the initial fluorescence intensity of the charge transport material 14a of the unused charge transport layer 14 is measured using this deterioration determination device, the reference value Db is input to the signal input unit. This can be done by transferring the data to the storage unit.

The arithmetic unit receives the measurement value Dm from the signal input unit and the reference value Db from the storage unit, and outputs a warning signal when determining that the measurement value Dm is below a predetermined value (Db × α), for example. It has a function to output to the output unit.
Here, the predetermined value (Db × α) is a value for determining whether or not a warning signal should be output, and if it falls below this value, it is determined that a warning signal should be output. The warning signal should be output before the problem occurs in the formed image by the photoconductor 1, and when the printing of a predetermined number of sheets (for example, 1000 sheets) starts, the problem starts to occur in the formed image. . Note that α in the predetermined value (Db × α) is a coefficient smaller than 1 for calculating the predetermined value, and can be obtained by a prior experiment.
The signal output unit has a function of outputting a warning signal from the calculation unit to a display unit and a control unit described later of the image forming apparatus 100.

<Electrophotographic photoreceptor>
As described above, in the photoreceptor 1, the intermediate layer 12, the charge generation layer 13 containing the charge generation material 13 a, and the charge transport layer 14 containing the charge transport material 14 a are laminated on the conductive substrate 11 in this order. Being done. In this case, the charge generation layer 13 and the charge transport layer 14 constitute a photosensitive layer having a two-layer structure.
However, the photoconductor 1 in the present embodiment is an example, and the photoconductor 1 is not limited to this configuration in the present invention. For example, the intermediate layer is an optional component and can be omitted. Further, a protective layer may be provided on the outermost surface of the photoreceptor 1.
Hereafter, each component which comprises the photoreceptor 1 illustrated in this embodiment is demonstrated.

[Conductive substrate]
The constituent material of the conductive substrate 11 is not particularly limited as long as it has a function as an electrode of an electrophotographic photosensitive member and a function as a support member and is a material used in this field.
Specifically, a metal material such as aluminum, aluminum alloy, copper, zinc, stainless steel, and titanium; a metal foil, a metal deposition layer, or a deposition layer of a conductive compound such as a conductive polymer, tin oxide, or indium oxide; A laminated material in which the coating layer is laminated on the surface of the support can be used. Examples of the material of the support include polymer materials such as polyethylene terephthalate, nylon, and polystyrene, hard paper, and glass.
As the constituent material of the conductive substrate 11, aluminum alloys such as JIS3003, JIS5000, and JIS6000 are particularly preferably used.

The shape of the conductive substrate is preferably cylindrical or columnar.
If necessary, the surface of the conductive substrate 11 is irregularly reflected within a range that does not affect the image quality, such as anodic oxide film treatment, surface treatment with chemicals or hot water, coloring treatment, or roughening the surface. Processing may be performed.
The irregular reflection process is particularly effective when a laser is used as an exposure light source. That is, in the electrophotographic process using a laser as an exposure light source, the wavelengths of the laser light are uniform, so that the laser light reflected on the surface of the photoconductor and the laser light reflected inside the photoconductor cause interference. As a result, interference fringes due to the interference may appear on the image, resulting in an image defect. By subjecting the surface of the conductive substrate to irregular reflection treatment, it is possible to prevent image defects caused by interference of laser light having a uniform wavelength.

[Middle layer]
As in the present embodiment, the photoreceptor 1 preferably has an intermediate layer 12 between the conductive substrate 11 and the charge generation layer 13.
The intermediate layer (also referred to as “undercoat layer”) 12 has a function of preventing charge injection from the conductive substrate 11 to the photosensitive layer (the charge generation layer 13 and the charge transport layer 14). For this reason, it is possible to prevent the chargeability of the photoreceptor 1 from being lowered, to suppress the reduction of surface charges other than the portion to be erased by exposure, and to prevent the occurrence of defects such as fogging on the image. In particular, in the image formation by the reversal development process, the occurrence of image fog due to the formation of minute black dots made of toner on the white background portion is prevented.
The intermediate layer 12 is prepared by, for example, preparing a coating solution for forming an intermediate layer by dissolving a resin material in an appropriate solvent, applying the coating solution to the surface of the conductive substrate 11, and removing the organic solvent by drying. Can be formed.

Examples of the resin material include natural polymer materials such as casein, gelatin, polyvinyl alcohol, and ethyl cellulose in addition to the same binder resin as that included in the charge generation layer 13 described later. More than seeds can be used. Among these resins, polyamide resins are preferable, and alcohol-soluble nylon resins are particularly preferable.
Examples of alcohol-soluble nylon resins include 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 2-nylon and 12-nylon, which are so-called copolymer nylon, and N- Examples thereof include resins obtained by chemically modifying nylon such as alkoxymethyl-modified nylon and N-alkoxyethyl-modified nylon.

Examples of the solvent for dissolving or dispersing the resin material include water, alcohols such as methanol, ethanol and butanol, glymes such as methyl carbitol and butyl carbitol, chlorinated solvents such as dichloroethane, chloroform and trichloroethane, acetone, Examples include dioxolane and mixed solvents in which two or more of these solvents are mixed. Among these solvents, non-halogen organic solvents are preferably used in consideration of environmental pollution.
Examples of the coating method of the intermediate layer 12 include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, an ink jet coating method, and a dip coating method.

Moreover, the coating liquid for intermediate | middle layer formation may contain the metal oxide particle.
The metal oxide particles can easily adjust the volume resistance value of the intermediate layer 12, and can maintain the electrical characteristics of the photoreceptor 1 under various environments.
Further, the metal oxide particles suppress the reflection of the laser beam on the conductive substrate 11 of the intermediate layer 12 and prevent the generation of interference fringe-like defective images (moire).
Examples of the metal oxide particles include titanium oxide, aluminum oxide, aluminum hydroxide, and tin oxide.
The ratio (C / D) of the total weight C of the binder resin and metal oxide particles in the coating liquid for forming an intermediate layer to the weight D of the solvent is preferably 1/99 to 40/60, and 2/98 to 30 /. 70 is particularly preferred.
The ratio E / F between the weight E of the binder resin and the weight F of the metal oxide particles is preferably 90/10 to 1/99, and particularly preferably 70/30 to 5/95.

The film thickness of the intermediate layer 12 is not particularly limited, but is preferably 0.01 to 20 μm, particularly preferably 0.05 to 10 μm.
When the thickness of the intermediate layer 12 exceeds 20 μm, it is difficult to form the intermediate layer 12 having a uniform thickness, and therefore, it becomes difficult to form the charge generation layer 13 having a uniform thickness on the intermediate layer 12. The sensitivity of 1 may be reduced. On the other hand, when the film thickness of the intermediate layer 12 is less than 0.01 μm, the intermediate layer 12 does not substantially function as an undercoat layer, and there is a possibility that a uniform intermediate layer surface cannot be obtained by covering defects of the conductive substrate 11. is there. That is, it becomes impossible to prevent the injection of charges from the conductive substrate 11 to the photosensitive layer, and the chargeability of the photoreceptor 1 is reduced.
When the constituent material of the conductive substrate 11 is aluminum, a layer containing alumite (alumite layer) can be formed and the layer can function as the intermediate layer 12.

[Charge generation layer]
The charge generation layer 13 contains a charge generation material 13 that generates charges by absorbing light as a main component.
Examples of the charge generation material 13a include azo pigments such as monoazo pigments, bisazo pigments, and trisazo pigments; indigo pigments such as indigo and thioindigo; perylene pigments such as peryleneimide and perylene anhydride; anthraquinone and pyrenequinone Polycyclic quinone pigments such as: metal phthalocyanines such as oxotitanium phthalocyanine compounds and phthalocyanine compounds such as metal-free phthalocyanines; organic photoconductive materials such as squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes; selenium and amorphous Inorganic photoconductive materials such as quality silicon.
One of these charge generation materials may be used alone, or two or more of these charge generation materials may be used in combination.
Among these charge generating materials, it is preferable to use an oxotitanium phthalocyanine compound represented by the following general formula (A).

In the general formula (A), X ¹ , X ² , X ³ and X ⁴ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and r, s, y and z are each 0-4. Indicates an integer.
Oxo titanyl phthalocyanine is a charge generation material having high charge generation efficiency and charge injection efficiency in the oscillation wavelength region (near infrared light) of laser light and LED light that is generally used at present. Therefore, oxo titanyl phthalocyanine generates a large amount of charge by absorbing light, and efficiently injects the generated charge into the charge transport material without accumulating inside it.

The oxotitanium phthalocyanine compound represented by the general formula (A) is produced according to a conventionally known production method such as, for example, the method described in Phthhalocyanine Compounds by Moser and Thomas, Reinhold Publishing Corp., New York, 1963. Can do.
For example, among the oxotitanium phthalocyanine compounds represented by the general formula (A), oxotitanium phthalocyanine in which X ¹ , X ² , X ³ and X ⁴ are all hydrogen atoms is obtained by heating phthalonitrile and titanium tetrachloride. Dichlorotitanium phthalocyanine can be synthesized by melting or heat-reacting in a suitable solvent such as α-chloronaphthalene and then hydrolyzing with a base or water. Alternatively, oxotitanium phthalocyanine can also be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

  The charge generation layer 13 may contain a binder resin in order to improve the binding property. Examples of the binder resin include polyester resin, polystyrene resin, polyurethane resin, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate resin, polyarylate resin, phenoxy resin, and polyvinyl butyral resin. And a resin such as a polyvinyl formal resin, and a copolymer resin containing two or more of the repeating units constituting these resins.

Specific examples of the copolymer resin include insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin. Can be mentioned.
The binder resin is not limited to the above, and a resin generally used in this field can be used as the binder resin. Binder resin may be used individually by 1 type, or 2 or more types may be used together.

  The ratio of the charge generation material in the charge generation layer 13 is preferably 10 wt% to 99 wt%. If the ratio of the charge generation material is less than 10% by weight, the sensitivity of the photoreceptor 1 may be lowered. On the other hand, if the ratio of the charge generation material exceeds 99% by weight, the binder resin content is too low, and the film strength of the charge generation layer 13 may be reduced. Furthermore, the dispersibility of the charge generation material in the charge generation layer 13 decreases, the coarse particles of the charge generation material increase, and the surface charge other than the portion to be erased decreases by exposure. As a result, the image defect, particularly toner adheres to a white background and a minute black spot is formed, which may increase the fog of the image.

As a method for forming the charge generation layer 13, a vacuum deposition method in which the charge generation material 13 a is vacuum deposited on the conductive substrate 11, or a charge generation layer coating solution containing the charge generation material 13 a in a solvent is applied to the conductive substrate 11. Examples of the method include a coating method for coating on the surface. Among these, a simple coating method is preferably used.
The coating solution for the charge generation layer can be prepared, for example, by adding the charge generation material 13a and, if necessary, the above-described binder resin in a suitable solvent and dispersing by a conventionally known method.

  Solvents used in the coating solution for the charge generation layer include, for example, halogenated hydrocarbons such as dichloromethane and dichloroethane, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, tetrahydrofuran (THF ), Ethers such as dioxane, alkyl ethers of ethylene glycol such as 1,2-dimethoxyethane, aromatic hydrocarbons such as benzene, toluene and xylene, N, N-dimethylformamide, N, N-dimethylacetamide, etc. Examples include aprotic polar solvents. One of these solvents may be used alone, or two or more thereof may be mixed and used as a mixed solvent. In consideration of environmental pollution, it is preferable to use a non-halogen solvent.

The charge generation material 13a may be pulverized in advance by a pulverizer before being dispersed in the solvent. Examples of the pulverizer used for the pulverization treatment include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser.
Examples of the disperser used when dispersing the charge generation material 13a in the solvent include a paint shaker, a ball mill, and a sand mill. As a dispersion condition at this time, an appropriate condition is selected so that impurities are not mixed due to wear of a container and a member constituting the disperser.
Examples of the coating method for the charge generation layer coating solution include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, an inkjet coating method, and a dip coating method.

  The layer thickness of the charge generation layer 13 is preferably 0.05 to 5 μm, more preferably 0.1 to 1 μm. If the layer thickness of the charge generation layer 13 is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity of the photoreceptor 1 may be lowered. On the other hand, if the layer thickness of the charge generation layer 13 exceeds 5 μm, the charge movement inside the charge generation layer 13 becomes a rate-determining step in the process of erasing the charge on the surface of the photosensitive layer, and the sensitivity of the photoreceptor 1 may be lowered. .

[Charge transport layer]
In the present invention, as the charge transport material 14a, as described above, for example, a charge transport material that generates fluorescence by absorbing light in a wavelength region of 360 to 460 nm can be used, and has a peak at 520 to 580 nm. Charge transport materials that produce fluorescence having a wavelength are preferred.
Specifically, examples of the charge transport material 14a include various compounds such as enamine compounds, styryl compounds, hydrazone compounds, triarylamine derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives, and benzidine derivatives. A known charge transport material can be used.
Among these, the compound represented by the general formula (I) is preferable.

（式中、
Ａｒ⁴及びＡｒ⁵は、互いに同一または異なって、水素原子、置換基を有してもよいアリール基、置換基を有してもよい複素環基、置換基を有してもよいアラルキル基または置換基を有してもよいアルキル基を表し、ただし、Ａｒ⁴及びＡｒ⁵が共に水素原子ではなく、Ａｒ⁴及びＡｒ⁵は、原子または原子団を介して互いに結合して環構造を形成してもよく、
ａは、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいジアルキルアミノ基、置換基を有してもよいアリール基、ハロゲン原子または水素原子を表し、
ｍは１〜６の整数であり、ｍが２以上のとき、複数のａは、同一または異なって、互いに結合して環構造を形成してもよく、
ｂ、ｃおよびｄは、同一または異なって、置換基を有してもよいアルキル基、置換基を有してもよいアルコキシ基、置換基を有してもよいジアルキルアミノ基、置換基を有してもよいアリール基、置換基を有してもよいアリールオキシ基、置換基を有してもよいアリールチオ基、ハロゲン原子または水素原子であり、
ｉ、ｋおよびｊは、同一または異なって、１〜５の整数であり、ｉが２以上のとき、複数のｂは、同一または異なって、互いに結合して環構造を形成してもよく、ｋが２以上のとき、複数のｃは、同一または異なって、互いに結合して環構造を形成してもよく、ｊが２以上のとき、複数のｄは、同一または異なって、互いに結合して環構造を形成してもよい。）
で示される化合物が好ましい。 In particular, the following general formula (II):

(Where
Ar ⁴ and Ar ⁵ are the same or different from each other, and are a hydrogen atom, an aryl group that may have a substituent, a heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or Represents an alkyl group which may have a substituent, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms, and Ar ⁴ and Ar ⁵ are bonded to each other via an atom or an atomic group to form a ring structure. You can,
a represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, an aryl group which may have a substituent, a halogen atom; Or a hydrogen atom,
m is an integer of 1 to 6, and when m is 2 or more, a plurality of a may be the same or different and may be bonded to each other to form a ring structure;
b, c and d are the same or different and each has an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, or a substituent. An aryl group which may have a substituent, an aryloxy group which may have a substituent, an arylthio group which may have a substituent, a halogen atom or a hydrogen atom,
i, k and j are the same or different and each represents an integer of 1 to 5, and when i is 2 or more, a plurality of b may be the same or different and may be bonded to each other to form a ring structure; When k is 2 or more, a plurality of c may be the same or different and may be bonded to each other to form a ring structure. When j is 2 or more, a plurality of d is the same or different and are bonded to each other. To form a ring structure. )
The compound shown by these is preferable.

Among the compounds represented by the general formula (II), FIG. 5 shows a fluorescence spectrum of fluorescence generated by irradiating the following compound (1) with excitation light of 370 nm (MCPD-3700: Otsuka Electronics ( It is a graph which shows the result measured by Co., Ltd. product. In the compound (1), the maximum peak wavelength of the fluorescence wavelength is 530 nm.
Further, the compound represented by the general formula (II) includes the following compound (2). Similarly to compound (1), this compound (2) was also measured for the fluorescence spectrum of fluorescence generated by irradiation with excitation light. The maximum peak wavelength of the fluorescence wavelength was 532 nm.
FIG. 6 shows the fluorescence spectrum of the fluorescence generated by irradiating the triarylamine derivative, which is the following compound (3), which is a general charge transport material, with excitation light in the same manner as the compound (1). It is a graph which shows the result. In the compound (3), the maximum peak wavelength of the fluorescence wavelength is 430 nm.

The compounds (1) and (2) can be obtained, for example, by the method described in JP-A-2004-141666.
The compound (3) can be purchased as a reagent from Tokyo Chemical Industry Co., Ltd., for example.

As the binder resin used for the charge transport layer 14, a resin having excellent compatibility with the charge transport material 14a is preferable. Specific examples of such a binder resin include, for example, vinyl polymer resins such as polymethyl methacrylate resin, polystyrene resin, polyvinyl chloride resin, and copolymer resins thereof, as well as polycarbonate resin, polyester resin, polyester carbonate resin, Examples thereof include polysulfone resin, phenoxy resin, epoxy resin, silicone resin, polyarylate resin, polyamide resin, polyether resin, polyurethane resin, polyacrylamide resin, and phenol resin. Moreover, the thermosetting resin which partially bridge | crosslinked these resin is also mentioned. One of these resins may be used alone, or two or more of these resins may be mixed and used.
Among the above resins, polystyrene resin, polycarbonate resin, polyarylate resin, and polyphenylene oxide have a volume resistivity of 10 ¹³ Ω · cm or more, and are excellent in electrical insulation, and also in film properties and potential characteristics. Since it is excellent, it is preferably used.

In the charge transport layer 14, the weight ratio (A / B) of the weight (B) of the binder resin to the weight (A) of the charge transport material 14a is preferably 10/12 to 10/30, for example.
When the weight ratio A / B exceeds 10/30, the binder resin ratio becomes too high. Therefore, when the charge transport layer 14 is formed by the dip coating method, the viscosity of the coating liquid increases and the coating speed decreases. In addition, productivity may be significantly deteriorated. Further, if the amount of the solvent in the coating solution is increased in order to suppress an increase in the viscosity of the coating solution, a brushing phenomenon occurs, and the formed charge transport layer 14 may become cloudy. On the other hand, if the weight ratio A / B is less than 10/12, the ratio of the binder resin becomes too low, so that the wear resistance of the charge transport layer 14 decreases and the wear amount of the surface layer increases, and the charging of the photoreceptor 1 May decrease.

In order to improve the film formability, flexibility and surface smoothness, additives such as a plasticizer and a leveling agent may be added to the charge transport layer 14 as necessary.
Examples of the plasticizer include dibasic acid esters such as phthalate esters, fatty acid esters, phosphate esters, chlorinated paraffins, and epoxy type plasticizers.
As a leveling agent, a silicone type leveling agent can be mentioned, for example.
The charge transport layer 14 may be added with fine particles of an inorganic compound and an organic compound as necessary in order to increase mechanical strength and improve electrical characteristics.
Specific examples of such an inorganic compound include metal oxide fine particles such as titanium oxide. Specific examples of organic compound fine particles include fine particles of fluorine atom-containing polymers such as tetrafluoroethylene polymer fine particles.

The charge transport layer 14 is prepared by dissolving or dispersing a charge transport material, a binder resin, and, if necessary, an additive in a solvent to prepare a charge transport layer coating solution, and coating the coating solution on the surface of the charge generation layer 13. And then dried to remove the organic solvent.
Examples of the solvent used for the charge transport layer coating solution include aromatic hydrocarbons such as benzene, toluene, xylene and monochlorobenzene, halogenated hydrocarbons such as dichloromethane and dichloroethane, and ethers such as THF, dioxane and dimethoxymethyl ether. And aprotic polar solvents such as N, N-dimethylformamide. A solvent may be used individually by 1 type, or 2 or more types may be mixed and used for it. In addition, a solvent such as alcohols, acetonitrile or methyl ethyl ketone may be added to the solvent as necessary. Among these solvents, non-halogen organic solvents are preferably used in consideration of environmental pollution.

The charge transport layer 14 is formed by applying the charge transport layer coating solution to the charge generation layer using a known coating method such as a spray method, bar coating method, roll coating method, blade method, ring method, ink jet coating method or dip coating method. It can be formed by coating on 13.
The film thickness of the charge transport layer 14 is preferably 5 to 50 μm, more preferably 10 to 40 μm.
If the thickness of the charge transport layer 14 is less than 5 μm, the charge holding ability of the surface of the photoreceptor 1 may be reduced. On the other hand, if the thickness of the charge transport layer 14 exceeds 50 μm, the resolution of the photoreceptor 1 may be reduced.

<Configuration of image forming apparatus>
As shown in FIGS. 1 and 3, in the image forming apparatus 100, the photosensitive member 1 is rotatably supported by an apparatus main body (not shown) and is driven to rotate around the rotation axis 44 in the direction of an arrow 41 by a drive unit 43. Is done. The drive unit 43 includes, for example, a motor and a gear, and rotates the photosensitive member 1 at a predetermined peripheral speed by transmitting the driving force to the conductive substrate 11 as the core of the photosensitive member 1.
The charging unit 32, the exposure unit 31, the developing unit 33, the transfer unit 34, the cleaning unit 36, the charge removal unit 30, and the deterioration determination device 2 are arranged in this order along the outer peripheral surface of the photoconductor 1 as indicated by arrows 41. It arrange | positions from the rotation direction upstream of the body 1 toward the downstream.
The charging unit 32 is a charger that uniformly charges the outer peripheral surface of the photoreceptor 1 to a predetermined potential.

The exposure unit 31 includes a near-infrared semiconductor laser as a light source, and irradiates the surface (outer peripheral surface) of the photoreceptor 1 between the charging unit 32 and the developing unit 33 with light of a laser beam output from the light source. Then, the surface of the charged photoreceptor 1 is exposed according to image information. The light of the light source is repeatedly scanned in the main scanning direction in the direction in which the rotation axis 44 of the photoconductor 1 extends, whereby electrostatic latent images are sequentially formed on the surface of the photoconductor 1. That is, the charge amount of the photosensitive member 1 uniformly charged by the charging unit 32 varies depending on whether the laser beam is irradiated or not, and an electrostatic latent image is formed.
An infrared semiconductor laser may be used as the exposure unit 31.

  The developing unit 33 is a developing unit that develops an electrostatic latent image formed on the surface of the photoreceptor 1 by exposure with a developer (toner), and is disposed at a position facing the photoreceptor 1. The developing unit 33 supports a developing roller 33a that supplies toner to the outer peripheral surface of the photoreceptor 1 and the developing roller 33a so that the developing roller 33a can rotate about a rotation axis parallel to the rotation axis 44 of the photoreceptor 1 and also has toner in its internal space. And a casing 33b for containing a developer containing

  The transfer unit 34 is a transfer charger that transfers a toner image as a visible image formed on the outer peripheral surface of the photoreceptor 1 by development onto a transfer sheet 39 as a recording medium. That is, the transfer charger 34 is, for example, a non-contact type transfer unit that transfers a toner image onto the transfer paper 39 by applying a charge having a polarity opposite to that of the toner to the transfer paper 39. The transfer paper 39 is transported in the direction of the arrow 42 by a transport means (not shown) and supplied between the photosensitive member 1 and the transfer unit 34.

The cleaning unit 36 is a cleaner that removes and collects toner remaining on the outer peripheral surface of the photoconductor 1 after the transfer operation by the transfer unit 34, and a cleaning blade 36 a that peels off the toner remaining on the outer peripheral surface of the photoconductor 1; A recovery casing 36b for storing the toner separated by the cleaning blade 36a.
The charge removal unit 30 is a charge removal lamp that removes charge by irradiating the outer peripheral surface of the photoreceptor 1 with charge removal light (for example, a wavelength of 600 nm to 850 nm). By using the light in the wavelength region as the charge removal light, it is possible to suppress the deterioration of the photoreceptor 1 due to the discharge of the charge removal light.

The fixing unit 35 is a fixing device that fixes the transferred image on the transfer paper 39 that has passed between the photoreceptor 1 and the transfer unit 34. The fixing unit 35 includes a heating roller 35a having a heating unit (not shown) and a pressure roller 35b that is disposed to face the heating roller 35a and presses the transfer paper 39 toward the heating roller 35a.
In FIG. 1, reference numeral 37 indicates a separating unit that separates the transfer sheet 39 from the photosensitive member 1, and reference numeral 38 indicates a housing (casing) that accommodates each component of the image forming apparatus 100.

The display unit 42 includes a display panel (for example, a liquid crystal panel) that displays the state of the image forming apparatus, a memory that stores various display contents for display on the display panel, and the like. Here, the various display contents are contents for explaining the state of the image forming apparatus 100, and among these display contents, display contents that prompt the replacement of the photoreceptor 1 are included.
The control unit 41 is configured to control each component of the image forming apparatus 100. Specifically, the control unit 41 is electrically connected to the display unit 42 and the drive unit 43 through a signal line, and controls the display unit 42 to display display contents corresponding to the state of the image forming apparatus 100. In addition, the driving and stopping of the driving unit 43 are controlled at a predetermined timing.

<Operation of Image Forming Apparatus>
The image forming operation by the image forming apparatus 100 is performed as follows.
First, when the photosensitive member 1 is rotationally driven by the drive unit 34 in the direction of the arrow 41, the surface of the photosensitive member 1 is uniformly charged to a predetermined positive potential by the charging unit 32.
Next, light corresponding to the image information is irradiated from the exposure unit 31 toward the surface of the photoreceptor 1. By this exposure, the surface charge of the portion irradiated with light on the photoreceptor 1 is removed, and a difference occurs between the surface potential of the portion irradiated with light and the surface potential of the portion not irradiated with light. An image is formed.

Next, toner is supplied to the surface of the photosensitive member 1 having an electrostatic latent image from a developing unit 33 disposed downstream of the light imaging point of the exposure unit 31 in the rotation direction of the photosensitive member 1, thereby The electrostatic latent image is developed to form a toner image.
In synchronization with the exposure of the photosensitive member 1, a transfer sheet 39 is supplied between the photosensitive member 1 and the transfer unit 34. The transfer unit 34 applies a charge having a polarity opposite to that of the toner to the transfer paper 39, whereby the toner image formed on the surface of the photoreceptor 1 is transferred onto the transfer paper 39.

  The transfer sheet 39 onto which the toner image has been transferred is conveyed to the fixing unit 35 by the conveying unit, and passes through a contact portion between the heating roller 35a and the pressure roller 35b of the fixing unit 35. At this time, the transfer paper 39 is heated and pressurized, whereby the toner image is fixed on the transfer paper 39 to form a robust image. The transfer sheet 39 on which the image is formed in this manner is discharged to the outside of the image forming apparatus 100 by the conveying unit.

On the other hand, after the toner image is transferred to the transfer paper 39 by the transfer unit 34, the toner remaining on the surface of the photoconductor 1 is separated from the surface of the photoconductor 1 by the cleaning unit 36 and collected.
The charge on the surface of the photoreceptor 1 from which the toner has been removed is removed by light from the charge eliminating portion (charge eliminating lamp) 30, and thereby the electrostatic latent image on the surface of the photoreceptor 1 disappears.
Thereafter, the photosensitive member 1 is further driven to rotate, and a series of operations starting from charging is repeated to form images continuously.

<Operation of degradation determination device>
Next, the operation of the electrophotographic photoreceptor deterioration determination apparatus of the present invention will be described with reference to FIGS.
The deterioration determination of the photoconductor 1 by the deterioration determination device 2 may be performed in a state where the photoconductor 1 is stationary (a stop state of the drive unit 43), or a state where the photoconductor 1 is rotating (a drive unit 43). In the driving state).
When the deterioration determination is performed in a state where the photoconductor 1 is rotating, when detecting the fluorescence of the charge transport material 14a emitted by the excitation light Le emitted from the light irradiation unit 2A, the detection timing of the fluorescence is the photoconductor. It is preferably controlled to synchronize with the rotation of one.
In other words, when a detection region exists in the image area of the photoconductor 1, it is from the start of the rotation of the photoconductor 1 to the start of the image forming operation or from the end of the image forming operation to the stop of the rotation of the photoconductor 1. Make a decision in between.
If a detection area is provided outside the image area of the photosensitive member 1, it is not necessary to synchronize the fluorescence detection with the timing of image formation.

  Further, the deterioration determination of the photosensitive member 1 by the deterioration determination device 2 is periodically performed by managing, for example, the cumulative number of printed sheets or the cumulative operation time by the image forming apparatus 100. In this case, for example, when the cumulative number of printed sheets is 8000, 8500, 8600, 8650, or when the cumulative operation time is 1000 hours, 1100 hours, 1150 hours, 1175 hours, the deterioration determination is performed. The degradation determination may be divided into a plurality of times, and the degradation determination interval may be shortened as the cumulative usage amount of the image forming apparatus 100 increases.

When the deterioration determination device 2 determines the deterioration of the photosensitive member 1 when the driving unit 43 is stopped or driven, the excitation light Le emitted from the light irradiation unit 2A is incident on the charge transport layer 14 and is charged. 14a is excited. Then, the generated fluorescence Lf is emitted from the charge transport layer 14 to the outside, the fluorescence Lf is detected by the fluorescence detection unit 2B, and a fluorescence intensity signal corresponding to the fluorescence intensity is transmitted from the fluorescence detection unit 2B to the evaluation unit 2C. It is sent to the signal input unit.
The fluorescence intensity signal input to the signal input unit is converted into a measurement value Dm and input to the calculation unit. On the other hand, a reference value Db is input from the storage unit to the calculation unit. Thereafter, in the calculation unit, it is determined whether or not the equation of measured value Dm <predetermined value (Db × α) is satisfied. If it is determined that this equation is satisfied, a warning signal is transmitted from the calculation unit via the signal output unit. Input to the control unit 41 of the image forming apparatus 100.
If it is determined that the above expression is not satisfied, no warning signal is input to the control unit 41.

  When a warning signal is input to the control unit 41, a command signal for displaying the display content that prompts replacement of the photosensitive member is transmitted from the control unit 41 to the display unit 42. Thereby, for example, the characters “Please replace the photoconductor” are displayed on the display panel of the display unit 42. Therefore, the user of the image forming apparatus 100 can recognize the replacement timing of the photosensitive member 1 before a problem occurs in the formed image by viewing this display, and can request the service person to replace the photosensitive member 1. Further, for example, a warning signal is continuously input to the control unit 41 until it is detected that the replacement of the photosensitive member 1 is completed, and transmission is stopped when a service person presses a reset button provided in the image forming apparatus 100. To do.

  Furthermore, when a warning signal is input to the control unit 41, a command signal for stopping the drive unit 43 may be transmitted from 41 to the drive unit 43. In this case, if the drive unit 43 is stopped during printing in which the photosensitive member 1 is rotated, the user's business is hindered. Therefore, it is preferable to control the drive unit 43 by the control unit 41 so that the stopped state is maintained when the photosensitive member 1 is stopped. Alternatively, for example, a touch panel is adopted as the display unit 42, and “OK” is displayed next to the characters “Please replace the photoconductor” displayed on the touch panel, and the user touches the display portion of “OK” with a finger. The stopped state of the photoreceptor 1 may be released by touching.

<Production of electrophotographic photoreceptor>
[Example 1]
The photoreceptor 1 having the laminated structure shown in FIG. 4 was produced as follows.
First, 7 parts by weight of titanium oxide (manufactured by Ishihara Sangyo Co., Ltd .: TTO55A) and 13 parts by weight of copolymer nylon resin (manufactured by Toray Industries, Inc .: Amilan CM8000) were mixed with 159 parts by weight of methanol and 106 parts by weight of 1,3-dioxolane. In addition to the mixed solvent containing, a coating shaker was dispersed for 8 hours to prepare an intermediate layer coating solution. The obtained intermediate layer coating solution was filled in a coating tank, and a cylindrical aluminum substrate 11 having a diameter of 40 mm and a length of 340 mm was immersed in the coating tank. Thereafter, the base body 11 was pulled up and naturally dried to form an intermediate layer 12 having a layer thickness of 1 μm on the outer peripheral surface of the base body 11.

  Next, 1 part by weight of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: ESREC BX-1) as binder resin 18 is dissolved in 98 parts by weight of tetrahydrofuran (THF), and titanyl phthalocyanine (compound ( B)) After adding 1 part by weight, the mixture was dispersed with a paint shaker for 2 hours to prepare a charge generation layer coating solution. The substrate 11 on which the intermediate layer 12 is laminated is immersed in the obtained coating tank filled with the charge generating layer coating solution, and after the charge generating coating solution is applied onto the intermediate layer 12, the substrate 11 is pulled up. The film was naturally dried to form a charge generation layer 13 having a layer thickness of 0.3 μm.

  Subsequently, 10 parts by weight of the compound (1) which is an enamine compound as the charge transport material 14a and 18 parts by weight of a bisphenol Z-type polycarbonate resin (Mitsubishi Engineering Plastics Co., Ltd .: Iupilon Z-200) which is a binder resin 17 Were dissolved in 160 parts by weight of THF to prepare a coating solution for a charge transport layer. The substrate 11 on which the intermediate layer 12 and the charge generation layer 13 were laminated was immersed in the coating tank filled with the obtained coating solution for charge transport layer. Thereafter, the substrate 11 was pulled up and naturally dried to form a charge transport layer 14 having a layer thickness of 25 μm on the outer peripheral surface of the substrate 11, thereby obtaining the photoreceptor 1.

[Example 2]
In the formation of the charge transport layer 14, the photoconductor was prepared in the same manner as in Example 1, except that the following compound (2), which is an enamine compound, was used as the charge transport material 14a instead of the compound (1). 1 was obtained.

Example 3
In the formation of the charge transport layer 14, the photoconductor was prepared in the same manner as in Example 1 except that the following compound (3), which is an amine compound, was used as the charge transport material 14 a instead of the compound (1). 1 was obtained.

<Deterioration Determination of Photoreceptors of Examples 1 to 3>
A commercially available copying machine (AR-C160 manufactured by Sharp Corporation) was modified, and the deterioration determination device of the present invention was mounted instead of the drum marking sensor. Specifically, the modified machine used for Examples 1-3 was produced as follows.

As a unit combining the light irradiation unit and the fluorescence detection unit, a reflection type photosensor (KR1570 manufactured by Shinko Denshi Co., Ltd.) combining an ultraviolet light emitting diode and a silicon photodiode was used.
In this photosensor, the excitation light of the ultraviolet light emitting diode has an emission spectrum with a peak at about 365 nm, and the silicon photodiode has sensitivity over a range of about 470 nm to near infrared light. Further, only the silicon photodiodes of Examples 1 and 2 were provided with an ultraviolet cut filter on the light receiving surface.
According to the photosensor of the modified machine used in Examples 1 and 2, the direct light and the reflected light from the ultraviolet light emitting diode are cut, and the fluorescence shown in FIG. 5 of the compound 1 and the fluorescence of the compound 2 can be detected. it can.

  Further, the output of the photosensor 1 is monitored, and when the fluorescence intensity is lower than the predetermined value (Db × α) (when the measured value Dm <predetermined value (Db × α)), the photoconductor 1 is replaced in the display panel. The copier was modified to display a prompt. In order to confirm the evaluation result in a short time, the copier is modified so that ozone gas, NOx, etc. stay in a high concentration state in the apparatus by stopping the exhaust fan around the photoreceptor 1 at the time of deterioration judgment. did.

The photoreceptor 1 produced in Example 1 was mounted on this modified machine, and the deterioration of the photoreceptor 1 was determined as follows.
First, in the initial state, after confirming that no warning was displayed, print output was started. When a size A4 test chart was continuously output, a warning prompting replacement of the electrophotographic photosensitive member was displayed when 8000 sheets were output, but there was no density unevenness in the image. After that, when the photoconductor 1 was continuously output without being replaced, an image defect in which halftones were partially whitened when 10,000 sheets were exceeded.
When the photoreceptor 1 produced in Example 2 was mounted on the modified machine and the deterioration of the photoreceptor 1 was determined in the same manner as in Example 1, the same result as in Example 1 was obtained.

When the photoreceptor 1 produced in Example 3 was mounted on the modified machine and the deterioration of the photoreceptor 1 was determined in the same manner as in Example 1, the detection accuracy was slightly lower than in Examples 1 and 2, There was a case of malfunction. Specifically, there is a case where a warning prompting the replacement of the electrophotographic photosensitive member is not displayed in spite of the occurrence of an image defect in which the halftone is partially whitened.
The cause of the malfunction is that in Example 3, the fluorescence spectrum of the charge transport material has a short wavelength, and therefore an ultraviolet cut filter cannot be provided in the fluorescence detection unit. As a result, direct light from the ultraviolet light emitting diode and This may be due to the fact that the reflected light is mixed with the fluorescence and this mixed light is detected by the silicon photodiode.

As described above, according to the degradation determination apparatus of the present invention, if the photosensitive member 1 is replaced at the time of the warning display, the efficiency of work is improved while maintaining good image characteristics without interruption due to image problems. I was able to confirm that
Furthermore, as in Examples 1 and 2, it was found that the use of an enamine compound as a charge transport material is preferable in terms of preventing malfunction.

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Deterioration determination apparatus 2A Light irradiation part 2B Fluorescence detection part 2C Evaluation part 3 Case 11 Conductive base 12 Intermediate layer 13 Charge generation layer 13a Charge generation substance 14 Charge transport layer (charge transport substance containing layer)
14a Charge transport material 30 Static elimination part 31 Exposure part 32 Charging part 33 Development part 34 Transfer part 35 Fixing part 36 Cleaning part 41 Control part 42 Display part 43 Drive part Le Excitation light (ultraviolet light)
Lf fluorescence

Claims (9)

An electrophotographic photoreceptor deterioration determination device having a layer containing a charge transport material that receives and excites ultraviolet light having a predetermined wavelength and emits fluorescence to emit fluorescence,
A light irradiation unit that irradiates the charge transport material-containing layer with ultraviolet light having the predetermined wavelength that excites the charge transport material of the electrophotographic photosensitive member to be determined to generate fluorescence;
A fluorescence detector that receives fluorescence emitted by the charge transport material and measures fluorescence intensity;
By comparing the fluorescence intensity measured by the fluorescence detector with the initial fluorescence intensity measured in advance when the charge transport material-containing layer of the electrophotographic photoreceptor is unused, the charge transport material-containing layer An apparatus for determining deterioration of an electrophotographic photosensitive member, comprising: an evaluation unit that determines a degree of deterioration of the electrophotographic photoreceptor.   The evaluation unit outputs a warning signal when determining that Dm <Db × α (α is a coefficient smaller than 1) when the initial fluorescence intensity is the reference value D and the fluorescence intensity is the measured value Dm. The deterioration determination device for an electrophotographic photosensitive member according to claim 1, which is configured.   The deterioration determination apparatus according to claim 1, wherein the light irradiation unit is an ultraviolet light emitting diode, and the fluorescence detection unit is a silicon photodiode.   The deterioration determination apparatus according to claim 1, wherein the fluorescence detection unit includes a filter on a light receiving surface.   The said light irradiation part is comprised so that irradiation of 360-460 nm ultraviolet light can be irradiated, and the said fluorescence detection part is comprised so that detection of the light of wavelength 510-580 nm is possible to any one of Claims 1-4. Deterioration determination apparatus as described.   An electrophotographic photosensitive member having a surface on which an electrostatic latent image is formed, the deterioration determination device according to claim 1, a charging unit that charges the surface of the photosensitive member, and An exposure unit that forms an electrostatic latent image on the surface of the photoconductor, a developing unit that supplies toner to the electrostatic latent image on the surface of the photoconductor to form a toner image, and a toner image on the surface of the photoconductor An image forming apparatus comprising: a transfer unit that transfers to a recording medium; a cleaning unit that cleans the surface of the photoreceptor; and a fixing unit that fixes a toner image to the recording medium. The evaluation unit of the deterioration determination device warns that Dm <Db × α (α is a coefficient smaller than 1) when the initial fluorescence intensity is a reference value D and the fluorescence intensity is a measured value Dm. Configured to output a signal,
The image forming apparatus further includes a control unit to which the warning signal is input, a display unit and a drive unit electrically connected to the control unit,
The image forming apparatus according to claim 6, wherein the control unit has a function of controlling the display unit to display a display prompting replacement of the electrophotographic photosensitive member based on the warning signal.   The image forming apparatus according to claim 7, wherein the control unit has a function of controlling the drive unit to maintain a stopped state while the warning signal is input. The electrophotographic photosensitive member has the following general formula (I):

(Where
Ar ¹ and Ar ² are the same or different from each other, and each represents an aryl group which may have a substituent or a heterocyclic group which may have a substituent,
Ar ³ represents an aryl group that may have a substituent, a heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or an alkyl group that may have a substituent. ,
Ar ⁴ and Ar ⁵ are the same or different from each other, and are a hydrogen atom, an aryl group that may have a substituent, a heterocyclic group that may have a substituent, an aralkyl group that may have a substituent, or Represents an alkyl group which may have a substituent, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms, and Ar ⁴ and Ar ⁵ are bonded to each other via an atom or an atomic group to form a ring structure. You can,
a represents an alkyl group which may have a substituent, an alkoxy group which may have a substituent, a dialkylamino group which may have a substituent, an aryl group which may have a substituent, a halogen atom; Or a hydrogen atom,
m is an integer of 1 to 6, and when m is 2 or more, a plurality of a may be the same or different from each other and may be bonded to each other to form a ring structure;
R ¹¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent,
R ¹² , R ^13, and R ¹⁴ are the same or different from each other, and are a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent, or a complex that may have a substituent. Represents an aralkyl group which may have a ring group or a substituent,
n is an integer of 0 to 3, and when n is 2 or 3, the plurality of R ¹² are the same or different from each other, and the plurality of R ¹³ are the same or different from each other, provided that when n is 0, Ar ³ Represents a heterocyclic group which may have a substituent.
The image forming apparatus according to claim 6, further comprising a charge transport material-containing layer containing a charge transport material represented by the formula:

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