JP5106053B2 - Multilayer electrophotographic photoreceptor and method for producing multilayer electrophotographic photoreceptor - Google Patents

Description

  The present invention relates to a multilayer electrophotographic photoreceptor and a method for producing the multilayer electrophotographic photoreceptor. In particular, the present invention relates to a multilayer electrophotographic photosensitive member capable of effectively suppressing the generation of exposure memory even when images are continuously formed, and a stable and easy manufacturing method thereof.

In general, organic photoconductors are often used as electrophotographic photoconductors used in electrophotographic equipment such as copying machines and laser printers due to demands for low price and low environmental pollution. As a charge generating agent used in such an organic photoreceptor, phthalocyanine pigments that are sensitive to light of infrared or near-infrared wavelength irradiated from a semiconductor laser or an infrared LED are widely used.
In addition, such phthalocyanine pigments include metal-free phthalocyanine compounds, copper phthalocyanine compounds, titanyl phthalocyanine compounds, and the like depending on their chemical structures, and each phthalocyanine compound has various crystal forms depending on the production conditions. It is known to get.
In such a variety of phthalocyanine compound crystals having different crystal types, an electrophotographic photosensitive member using a titanyl phthalocyanine crystal having a Y-type crystal structure as a charge generating agent is a titanyl phthalocyanine crystal of another crystal type. It is known that the electrical characteristics are excellent as compared with the case of using.
For example, an organic compound capable of forming a phthalocyanine ring, which is a Y-type titanyl phthalocyanine crystal having a maximum diffraction peak at a Bragg angle (2θ ± 0.2 °) = 27.3 ° with respect to a Cu—Kα ray in an X-ray diffraction spectrum And a titanium compound are reacted in a dialkylaminoalcohol to which urea or ammonia is added at 130 ° C. for about 4 hours, and a method for producing a Y-type titanyl phthalocyanine crystal is disclosed (for example, patent document) 1).

Also disclosed is a method for producing a Y-type titanyl phthalocyanine crystal obtained by directly reacting o-phthalonitrile and titanium tetrabutoxide without using a urea compound and reacting them at 215 ° C. for about 2 hours. (For example, Patent Documents 2 and 3).
More specifically, a method for producing a Y-type titanyl phthalocyanine crystal having a peak in a predetermined range in a CuKα characteristic X-ray diffraction spectrum and having no temperature change peak in a range of 50 to 400 ° C. in differential scanning calorimetry. Is disclosed.
JP-A-8-176456 (Example) Patent No. 3463032 (Claims) JP 2004-145284 (Claims)

  However, in the case of Patent Document 1, since the addition ratio of the titanium compound to the organic compound capable of forming a phthalocyanine ring is small and the reaction temperature is low, the produced Y-type titanyl phthalocyanine crystal is in the photosensitive layer coating solution. There was a problem that the β-type or α-type crystal was likely to undergo crystal transition. For this reason, the storage stability of the photosensitive layer coating solution is poor, and as a result, there has been a problem that a photosensitive layer having good electrical characteristics cannot be formed stably.

On the other hand, when the Y-type titanyl phthalocyanine crystals described in Patent Document 2 and Patent Document 3 were used, the crystal transition in the photosensitive layer coating solution could be suppressed to some extent.
However, in Patent Document 2 and Patent Document 3, it is completely considered that even in the same Y-type titanyl phthalocyanine crystal, its charge generation ability and dispersibility vary greatly depending on the production conditions and the like. I did not.
Therefore, even if a Y-type titanyl phthalocyanine crystal that suppresses the crystal transition to some extent is obtained, its charge generation ability and dispersibility are not necessarily optimized, and the stability of its quality also varies. The problem of being seen was seen.
As a result, the Y-type titanyl phthalocyanine crystal of Patent Documents 2 and 3 is applied to a multilayer electrophotographic photosensitive member having many layer interfaces and charges are likely to remain in the photosensitive layer. When this is done, there has been a problem that exposure memory is likely to occur.
Therefore, while effectively suppressing the crystal transition of the Y-type titanyl phthalocyanine crystal, its charge generation ability and dispersibility are more effectively and stably exhibited, and even when continuous image formation is performed, There has been a demand for an electrophotographic photosensitive member that can effectively suppress the generation of exposure memory.

Therefore, as a result of intensive studies in view of the above-described problems, the present inventors have prescribed the optical characteristics of the Y-type titanyl phthalocyanine crystal within a predetermined range and placed the Y-type titanyl phthalocyanine crystal in a predetermined environment for a predetermined period. The change in optical characteristics in the case of the case has also been defined quantitatively. As a result, it was found that the charge generation ability and dispersibility can be exhibited more effectively and stably while effectively suppressing the crystal transition of the Y-type titanyl phthalocyanine crystal, and the present invention has been completed. is there.
That is, the object of the present invention is to continuously suppress the crystal transition of the Y-type titanyl phthalocyanine crystal as a charge generating agent and to exhibit its charge generating ability and dispersibility more effectively and stably. Accordingly, it is an object of the present invention to provide a laminated electrophotographic photosensitive member capable of effectively suppressing the generation of exposure memory even when image formation is performed, and a stable and easy manufacturing method thereof.

According to the present invention, there is provided a laminated electrophotographic photosensitive member in which a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate, wherein the charge generation agent comprises the following (A) initial characteristics and (B) Y-type titanyl phthalocyanine crystal having aging characteristics ,
A multilayer electrophotographic photosensitive member obtained by the steps including the following steps (a) to (e) is provided, and the above-described problems can be solved.
(A) Step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dropping a titanyl phthalocyanine solution into a poor solvent to obtain a wet cake
(D) A step of washing the wet cake with a washing solvent
(E) Step of obtaining Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) time-dependent characteristics by heating and stirring the wet cake after washing in a non-aqueous solvent (A) Initial characteristics
The Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ± 0.2 ° = Each has a peak at 7.4 ° and 9.6 °, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and the Bragg angle 2θ ± 0.2 ° When the peak intensity at 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days In other words, the optical properties of the titanyl phthalocyanine crystal in a stage where a coating liquid for actually forming a charge generation layer (hereinafter sometimes referred to as a charge generation layer coating liquid) is prepared within a predetermined range By prescribing, the crystal form can be a Y-type crystal excellent in charge generation ability and dispersibility.
In addition, the Y-type titanyl phthalocyanine crystal is actually charged by defining quantitatively the change in optical characteristics when it is kept in a predetermined environment for a predetermined period, more specifically, the crystal transition state to α-type. The charge generation ability and dispersibility can be more effectively and stably exhibited while effectively suppressing crystal transition at the stage of preparing the generation layer coating liquid.
Therefore, by using such a Y-type titanyl phthalocyanine crystal as a charge generating agent, it is possible to continuously form a multilayer electrophotographic photosensitive member having a large number of layer interfaces and charge remaining easily in the photosensitive layer. Even when image formation is performed, generation of exposure memory can be effectively suppressed.

In constructing the laminated electrophotographic photosensitive member of the present invention, as an initial characteristic (A) of the Y-type titanyl phthalocyanine crystal , in an X-ray diffraction spectrum using Cu-kα as a radiation source, a Bragg angle 2θ ± 0.2 It is preferable to have a peak at ° = 24.2 °.
By comprising in this way, the charge generation capability and dispersibility can be exhibited more effectively and stably, suppressing a crystal transition more effectively.

In constructing the multilayer electrophotographic photoreceptor of the present invention, the Y-type titanyl phthalocyanine crystal obtained by dissolving and dispersing the charge generation layer in tetrahydrofuran has the above-mentioned (A) initial characteristics and (B) time-dependent characteristics. It is preferable to have.
With this configuration, it is possible to obtain a multilayer electrophotographic photosensitive member that reliably retains the characteristics of the Y-type titanyl phthalocyanine crystal of the present invention even when the charge generation layer has already been formed.

In addition, in constructing the multilayer electrophotographic photosensitive member of the present invention, as a further requirement of the above-mentioned (B) time-dependent characteristics, the Y-type titanyl phthalocyanine crystal has Bragg in the X-ray diffraction spectrum using Cu-kα as a radiation source. It is preferable that there is no peak at the angle 2θ ± 0.2 ° = 26.2 °.
By comprising in this way, it can suppress more reliably that the crystal form of a Y-type titanyl phthalocyanine crystal transfers to (beta) type.

Another embodiment of the present invention is a method for producing a laminated electrophotographic photosensitive member in which a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate, and the method includes the following step (a): A method for producing a multilayer electrophotographic photoreceptor, comprising: (f).
(A) A step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal.
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dropping a titanyl phthalocyanine solution into a poor solvent to obtain a wet cake.
(D) A step of washing the wet cake using a washing solvent.
(E) A step of heating and stirring the washed wet cake in a non-aqueous solvent to obtain a Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) aging characteristics.
(A) Initial characteristics The Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ±. The peak at 0.2 ° = 7.4 ° and 9.6 °, respectively, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and the Bragg When the peak intensity at the angle 2θ ± 0.2 ° = 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days (f) A Y-type titanyl phthalocyanine crystal and a binder resin are dispersed in a solvent mainly containing at least one compound selected from alkyl acetate, alkylene glycol monoalkyl ether and alcohol. And a step of producing a charge generation layer coating solution.
That is, a specific Y-type titanyl phthalocyanine crystal can be efficiently manufactured by carrying out a manufacturing method including such steps.
In addition, the charge generation layer coating solution can be produced in a state where the characteristics of the Y-type titanyl phthalocyanine crystal are effectively maintained.
Accordingly, it is possible to stably and easily manufacture a multilayer electrophotographic photosensitive member capable of effectively suppressing the occurrence of exposure memory even when images are continuously formed.

In carrying out the method for producing a laminated electrophotographic photoreceptor of the present invention, the synthesis of the titanyl phthalocyanine compound in the step (a) is a synthesis by reaction of phthalonitrile or diiminoisoindoline with titanium alkoxide. At the same time, the amount of titanium alkoxide added to phthalonitrile or diiminoisoindoline is preferably set to a value in the range of 0.325 to 1 mol with respect to 1 mol of phthalonitrile or diiminoisoindoline.
By carrying out in this way, a specific Y-type titanyl phthalocyanine crystal can be obtained more efficiently.

In carrying out the method for producing a laminated electrophotographic photoreceptor of the present invention, the urea compound is used in an amount of 0 per mole of phthalonitrile or diiminoisoindoline in the synthesis of the titanyl phthalocyanine compound in the step (a). It is preferable to add at a value within the range of 5 to 3 mol.
By carrying out in this way, a specific Y-type titanyl phthalocyanine crystal can be obtained more efficiently.

In carrying out the method for producing a multilayer electrophotographic photosensitive member of the present invention, it is preferable to use alcohol as the cleaning solvent in step (d).
By carrying out in this way, impurities remaining in the wet cake can be effectively removed.

[First Embodiment]
The first embodiment of the present invention is a laminated electrophotographic photosensitive member in which a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate, wherein the charge generation agent is (A 1) A Y-type titanyl phthalocyanine crystal having initial characteristics and (B) aging characteristics, which is obtained by a process including the following processes (a) to (e). .
(A) Step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dropping a titanyl phthalocyanine solution into a poor solvent to obtain a wet cake
(D) A step of washing the wet cake with a washing solvent
(E) Step of obtaining Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) time-dependent characteristics by heating and stirring the wet cake after washing in a non-aqueous solvent (A) Initial characteristics
The Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ± 0.2 ° = Each has a peak at 7.4 ° and 9.6 °, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and the Bragg angle 2θ ± 0.2 ° When the peak intensity at 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days Hereinafter, the laminated electrophotographic photosensitive member according to the first embodiment will be described in detail with respect to each constituent element.

1. Basic Configuration As shown in FIG. 1A, a multilayer electrophotographic photosensitive member 20 includes a charge generation layer 24 containing a charge generation agent and the like, a charge transfer agent, and the like on a substrate 12 by means of coating or the like. It can be created by forming a charge transport layer 22 containing
In contrast to the above-described structure, as shown in FIG. 1B, the charge transport layer 22 may be formed on the substrate 12, and the charge generation layer 24 may be formed thereon.
However, when formed in this way, the charge generation layer 24 may be easily damaged because the film thickness is much thinner than that of the charge transport layer 22. Therefore, it is preferable to form the charge transport layer 22 on the charge generation layer 24 as shown in FIG.
Further, as shown in FIG. 1C, it is also preferable to form an intermediate layer 25 on the substrate 12.
In general, the charge transport layer 22 preferably contains either a hole transport agent or an electron transport agent, but both a hole transport agent and an electron transport agent may be used.

2. 1. Substrate As the substrate 12 illustrated in FIG. 1, various materials having conductivity can be used. For example, substrates formed of metals such as iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, and the above-described metals are vapor-deposited Alternatively, a substrate made of a laminated plastic material, a glass substrate coated with aluminum iodide, alumite, tin oxide, indium oxide, or the like is exemplified.
That is, it is only necessary that the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the substrate has sufficient mechanical strength when used.
The shape of the substrate may be any of a sheet shape and a drum shape according to the structure of the image forming apparatus to be used.

3. Intermediate Layer Further, as shown in FIG. 1C, an intermediate layer 25 containing a predetermined binder resin may be provided on the base 12.
This is because the adhesion between the substrate and the photosensitive layer is improved, and by adding a predetermined fine powder in this intermediate layer, the incident light is scattered to suppress the generation of interference fringes, This is because charge injection from the substrate to the photosensitive layer during non-exposure that causes black spots can be suppressed. The fine powder is not particularly limited as long as it has light scattering properties and dispersibility, and examples thereof include white pigments such as titanium oxide, zinc oxide, zinc white, zinc sulfide, lead white, and lithopone. Inorganic pigments such as alumina, calcium carbonate, barium sulfate and the like, fluorine resin particles, benzoguanamine resin particles, styrene resin particles, and the like can be used.

Moreover, it is preferable to make the film thickness of this intermediate | middle layer into the value within the range of 0.1-50 micrometers. This is because if the intermediate layer is too thick, a residual potential is likely to be generated on the surface of the photoreceptor, which may cause a decrease in electrical characteristics. On the other hand, if the intermediate layer thickness is too thin, the unevenness of the substrate surface cannot be sufficiently relaxed, and the adhesion between the substrate and the photosensitive layer cannot be obtained.
Therefore, the thickness of the intermediate layer is preferably set to a value in the range of 0.1 to 50 μm, and more preferably set to a value in the range of 0.5 to 30 μm.

4). Charge generation layer (1) Charge generation agent (1) -1 Titanyl phthalocyanine compound As a titanyl phthalocyanine compound constituting a Y-type titanyl phthalocyanine crystal as a charge generation agent in the present invention, a compound represented by the following general formula (1) It is preferable that
This is because the titanyl phthalocyanine compound having such a structure can not only further improve the stability of the Y-type titanyl phthalocyanine crystal but also stably produce the Y-type titanyl phthalocyanine crystal. Because.
In particular, the structure of the titanyl phthalocyanine compound is preferably represented by the following general formula (2). Among them, an unsubstituted titanyl phthalocyanine compound represented by the following formula (3) is particularly preferable.
This is because a specific Y-type titanyl phthalocyanine crystal can be more easily produced by using a titanyl phthalocyanine compound having such a structure.

(In the general formula (1), X ¹ , X ² , X ³ and X ⁴ are the same or different substituents, and each represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cyano group, or a nitro group. And the repeating numbers a, b, c and d each represent an integer of 1 to 4, and may be the same or different.

(In general formula (2), X represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a cyano group, or a nitro group, and the repeating number e represents an integer of 1 to 4.)

(1) -2 Titanyl phthalocyanine crystal The titanyl phthalocyanine crystal as a charge generator in the present invention is characterized in that its crystal type is Y-type.
This is because the Y-type titanyl phthalocyanine crystal has a remarkably superior charge generation ability as compared with other crystal-type titanyl phthalocyanine crystals.
Therefore, by using such a Y-type titanyl phthalocyanine crystal as a charge generating agent, it is possible to efficiently generate a charge and form an electrostatic latent image with excellent sensitivity upon exposure to the photosensitive layer surface. it can.

Further, the Y-type titanyl phthalocyanine crystal is characterized by having (A) initial characteristics.
That is, the Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ± 0.2. Each peak has a peak at ° = 7.4 ° and 9.6 °, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and the Bragg angle 2θ ± 0. When the peak intensity at 2 ° = 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
The reason for this is that by defining the optical characteristics of the titanyl phthalocyanine crystal in the above-mentioned range in the stage of actually preparing the coating solution for the charge generation layer, the crystal type is Y type with excellent charge generation ability and dispersibility. It is because it can confirm reliably that it is a crystal | crystallization.
That is, the large peaks at the Bragg angles 2θ ± 0.2 ° = 27.2 ° and 9.6 ° are peaks that appear characteristically in the Y-type crystal.
On the other hand, the peak at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is a peak that becomes larger as the crystal form transitions to the α form. Therefore, when the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps) and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 9.6 ° is Y (cps) In addition, by setting the value of X / Y (−) to a value less than 0.3, the degree of crystal transition from Y-type to α-type in the stage of actually creating the charge generation layer coating liquid is strictly determined. Can be prescribed.
The lower limit of the value of X / Y (−) is preferably 0, that is, it is preferable that there is no peak at Bragg angle 2θ ± 0.2 ° = 7.4 °. is there.
Therefore, the value of X / Y (−) is more preferably a value within the range of 0.02 to 0.3, and even more preferably a value within the range of 0.05 to 0.25.

In addition, the Y-type titanyl phthalocyanine crystal is characterized by having (B) time-dependent characteristics.
That is, when the above-described Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the above-mentioned X / Y (−) value is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days The reason for this is that the coating solution for the charge generation layer is actually prepared by quantitatively defining the change in optical properties when the Y-type titanyl phthalocyanine crystal is placed in a predetermined environment for a predetermined period. This is because the charge generation ability and dispersibility can be more effectively and stably exhibited while effectively suppressing the crystal transition in the stage.
That is, originally Y-type titanyl phthalocyanine crystals tend to transition to α-type or β-type when immersed in tetrahydrofuran. Therefore, in the prior art, emphasis has been placed on suppressing such transition to α-type or β-type.
Also in the present invention, as described above, the Y-type titanyl phthalocyanine crystal in the stage of actually creating the charge generation layer coating liquid is characterized by using one that suppresses the transition to α-type as much as possible. .
However, on the other hand, in the present invention, when stirring under a predetermined condition, the X / Y (−) value is a predetermined value or more, a Y-type titanyl phthalocyanine crystal, that is, a transition to α-type. Is characterized by using a Y-type titanyl phthalocyanine crystal which is relatively easy to generate. This is because the Y-type titanyl phthalocyanine crystal is relatively easily transferred to the α-type as much as possible (the peak at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is relatively easy to grow). When used as a charge generating agent, a Y-type titanyl phthalocyanine crystal is used in which the transition to α-type is relatively difficult to occur (the peak at Bragg angle 2θ ± 0.2 ° = 7.4 ° is relatively difficult to grow). This is because it has been found that the charge generation ability and dispersibility can be effectively and stably exhibited rather than the case of the conventional case.
However, if the transition to α-type is apt to occur excessively, it may be difficult to use it as a charge generator while maintaining the Y-type.
Therefore, when the Y-type titanyl phthalocyanine crystal is stirred under a predetermined condition, the value of X / Y (−) is preferably a value within the range of 0.5 to 1000, More preferably, the value is within the range.
In addition, the measuring method of the optical characteristic in a Y-type titanyl phthalocyanine crystal | crystallization is described in a subsequent Example.

Next, with reference to FIG. 2, the value of X / Y (−) when the Y-type titanyl phthalocyanine crystal is stirred under a predetermined condition (hereinafter sometimes referred to as α degree) and the exposure memory Explain the relationship.
In FIG. 2, a characteristic curve is shown in which the abscissa indicates the degree of alphaization (−) after stirring and the ordinate indicates the memory potential (V).
In addition, it shows that it is hard to generate | occur | produce exposure memory, so that the value of memory potential is small.
In addition, as the Y-type titanyl phthalocyanine crystal, the value of the degree of α-ization at the initial stage, that is, the value of the degree of alpha-ization at the stage before stirring under a predetermined condition is all less than 0.3. Type titanyl phthalocyanine crystals were used.
In addition, the details of the memory potential measurement method and the like will be described in detail in a later embodiment.
As can be understood from the characteristic curve, when the value of the degree of α after stirring is in the range of less than 0.5, the value of the memory potential decreases rapidly as the value increases. More specifically, it can be seen that there is a rapid decrease from a value of at least 45V to a value of around 25V. On the other hand, it can be seen that the value of the memory potential is stably maintained at a low value of around 25 V in the range where the value of the degree of α after stirring is 0.5 or more.
Therefore, it can be seen that the occurrence of exposure memory can be critically suppressed by setting the value of the degree of alpha conversion to 0.5 or more when the Y-type titanyl phthalocyanine crystal is stirred under predetermined conditions.

The Y-type titanyl phthalocyanine crystal preferably has a peak at a Bragg angle 2θ ± 0.2 ° = 24.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source.
The reason for this is that by having a peak at a Bragg angle 2θ ± 0.2 ° = 24.2 °, the crystal generation is more effectively suppressed, and the charge generation ability and dispersibility are more effectively and stably achieved. It is because it can be demonstrated.
That is, the peak at the Bragg angle 2θ ± 0.2 ° = 24.2 ° is smaller in intensity than the peaks at the Bragg angles 2θ ± 0.2 ° = 27.2 ° and 9.6 °. This is because the peak is characteristically seen in the Y-type titanyl phthalocyanine crystal.
Therefore, by defining the presence of such a peak, the degree of crystal transition from the Y type to another type in the stage of actually creating the charge generation layer coating liquid can be more strictly defined.

In addition, when the Y-type titanyl phthalocyanine crystal is stirred under predetermined conditions, it has a peak at a Bragg angle 2θ ± 0.2 ° = 26.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source. Preferably not.
This is because the Y-type titanyl phthalocyanine crystal has a peak at a Bragg angle of 2θ ± 0.2 ° = 26.2 ° when left in a predetermined environment for a predetermined period. This is because the transition of the crystal form to the β form can be more reliably suppressed.
That is, the peak at the Bragg angle 2θ ± 0.2 ° = 26.2 ° is a peak that appears characteristically in the β-type crystal.

Moreover, it is preferable that a Y-type titanyl phthalocyanine crystal has the following characteristics (a) or (b).
(A) In the differential scanning calorimetry, there is no peak in the range of 50 to 400 ° C. other than the peak due to vaporization of the adsorbed water. (B) In the differential scanning calorimetry, except for the peak due to vaporization of the adsorbed water. , Having no peak in the range of 50 to 270 ° C., and having one peak in the range of 270 to 400 ° C. The reason for this is that the charge generation ability and dispersibility are effective due to this configuration. It is because it can be made to exhibit efficiently and stably.
In addition, it is more preferable that one peak appearing in the range of 270 to 400 ° C. other than the peak accompanying vaporization of the adsorbed water appears in the range of 290 to 400 ° C., and the range of 300 to 400 ° C. More preferably, it appears within.

(1) -3 Content Further, the content of the charge generating agent is preferably set to a value within the range of 5 to 1000 parts by weight with respect to 100 parts by weight of the binder resin constituting the charge generating layer.
The reason for this is that when the content is less than 5 parts by weight with respect to 100 parts by weight of the binder resin, the charge generation amount becomes insufficient and it becomes difficult to form a clear electrostatic latent image. This is because there are cases. On the other hand, when the content exceeds 1000 parts by weight with respect to 100 parts by weight of the binder resin, it may be difficult to form a uniform charge generation layer.
Therefore, the content of the charge generating agent with respect to 100 parts by weight of the binder resin constituting the charge generating layer is more preferably set to a value within the range of 30 to 500 parts by weight.

(2) Binder resin The binder resin used for the charge generation layer is polycarbonate resin such as bisphenol A type, bisphenol Z type or bisphenol C type, polyester resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polystyrene. Resin, polyvinyl acetate resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-alkyd Examples thereof include a single type of resin, N-vinylcarbazole, or a combination of two or more types.

(3) Film thickness Moreover, it is preferable to make the thickness of a charge generation layer into the value within the range of 0.1-5 micrometers.
This is because the amount of charge generated by exposure can be improved by setting the thickness of the charge generation layer to a value in the range of 0.1 to 5 μm.
That is, if the thickness of the charge generation layer is less than 0.1 μm, it may be difficult to form a charge generation layer having sufficient charge generation capability. On the other hand, if the thickness of the charge generation layer exceeds 5 μm, it may be difficult to suppress the generation of residual charges or it may be difficult to form a uniform charge generation layer.
Therefore, the thickness of the charge generation layer is more preferably set to a value within the range of 0.15 to 4 μm, and further preferably set to a value within the range of 0.2 to 3 μm.

(4) Characteristics after dissolution It is preferable that the Y-type titanyl phthalocyanine crystal in the stage where the charge generation layer has already been formed has (A) initial characteristics and (B) temporal characteristics.
That is, the Y-type titanyl phthalocyanine crystal obtained by dissolving and dispersing the charge generation layer in tetrahydrofuran preferably has (A) initial characteristics and (B) temporal characteristics.
This is because the optical characteristics of the Y-type titanyl phthalocyanine crystal as the charge generating agent in the already formed charge generating layer are also defined as described above, so that the present invention can be applied even when the charge generating layer is formed. This is because it is possible to obtain a laminated electrophotographic photosensitive member that reliably retains the characteristics of the Y-type titanyl phthalocyanine crystal.
That is, in the step of preparing the coating solution for charge generation layer, even if it has the optical characteristics of the Y-type titanyl phthalocyanine crystal in the present invention, the optical characteristics may change in the formed charge generation layer. Because there is.
As a cause of such a change, for example, an influence of a solvent when preparing a coating solution for a charge generation layer, an influence of a binder resin, or the like can be considered.

Next, referring to FIG. 3, the value of X / Y (−) (degree of α conversion) when Y-type titanyl phthalocyanine crystal obtained by dissolving and dispersing the charge generation layer in tetrahydrofuran is stirred under predetermined conditions. ) And the exposure memory will be described.
In FIG. 3, the horizontal axis represents the characteristic curve with the α degree after stirring (−) taken, and the vertical axis taken the memory potential (V).
In addition, it shows that it is hard to generate | occur | produce exposure memory, so that the value of memory potential is small.
In addition, as the Y-type titanyl phthalocyanine crystal, the value of the degree of α-ization at the initial stage, that is, the value of the degree of alpha-ization at the stage before stirring under a predetermined condition is all less than 0.3 Type titanyl phthalocyanine crystals were used.
In addition, the details of the memory potential measurement method and the like will be described in detail in a later embodiment.
As understood from the characteristic curve, when the value of the degree of α after stirring is in the range of less than 0.5, the value of the memory potential decreases rapidly with the increase. More specifically, it can be seen that there is a rapid decrease from a value of at least 45V to a value of around 25V. On the other hand, it can be seen that the value of the memory potential is stably maintained at a low value of around 25 V in the range where the value of the degree of α after stirring is 0.5 or more.
Therefore, the Y-type titanyl phthalocyanine crystal obtained by dissolving and dispersing the charge generation layer in tetrahydrofuran is made to have a value of 0.5 or more in the case of stirring under a predetermined condition. It can be seen that generation can be critically suppressed.

5. Charge Transport Layer (1) Charge Transport Agent (1) -1 Type As the charge transport agent (hole transport agent and electron transport agent) used in the charge transport layer, 2,5-bis (p-diethylaminophenyl) -1, Oxadiazole derivatives such as 3,4-oxadiazole, 1,3,5-triphenyl-pyrazoline, 1- (pyridyl- (2))-3- (p-diethylaminostyryl) -5- (p-diethylamino) Pyrazoline derivatives such as styryl) pyrazoline, aromatic tertiary such as triphenylamine, tri (p-methyl) phenylamine, N, N-bis (3,4-dimethylphenyl) biphenyl-4-amine, dibenzylaniline Aromatic tertiary diamino such as amino compounds, N, N'-diphenyl-N, N'-bis (3-methylphenyl)-(1,1-biphenyl) -4,4'-diamine Compound, 1,2,4-triazine derivatives such as 3- (4′-dimethylaminophenyl) -5,6-di- (4′-methoxyphenyl) -1,2,4-triazine, 4-diethylaminobenzaldehyde Hydrazone derivatives such as -1,1-diphenylhydrazone, quinazoline derivatives such as 2-phenyl-4-styryl-quinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di (p-methoxyphenyl) -benzofuran, p- Hole transport materials such as α-stilbene derivatives such as (2,2-diphenylvinyl) -N, N-diphenylaniline, enamine derivatives, carbazole derivatives such as N-ethylcarbazole, poly-N-vinylcarbazole and derivatives thereof; Quinone compounds such as chloranil, bromoanil and anthraquinone, tetracyanoquinodimethane Compounds, electron transport materials such as 2,4,7-trinitrofluorenone, fluorenone compounds such as 2,4,5,7-tetranitro-9-fluorenone, xanthone compounds, thiophene compounds, diphenoquinone compounds; One kind or a combination of two or more kinds of polymers having a group to be formed in the main chain or side chain can be mentioned.

(1) -2 Content The content of the charge transfer agent is preferably set to a value in the range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the content of the charge transfer agent is less than 10 parts by weight, the sensitivity is lowered, which may cause a practical problem. On the other hand, when the content of the charge transport agent exceeds 100 parts by weight, the charge transport agent is easily crystallized, and an appropriate film may not be formed.
Therefore, it is more preferable to set the content of the charge transfer agent to a value within the range of 20 to 80 parts by weight.
As the charge transport agent to be used, either a hole transport agent or an electron transport agent is generally used according to the charging characteristics of the electrophotographic photosensitive member. An agent can also be used in combination.

(2) Additives In addition, for the purpose of preventing deterioration of the photoreceptor due to ozone, oxidizing gas, or light and heat generated in the electrophotographic apparatus, an antioxidant, a light stabilizer, and a heat stabilizer in the charge transport layer. It is preferable to add an agent or the like.
For example, antioxidants include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and their derivatives, organic sulfur compounds, organic phosphorus compounds, benzophenone, benzotriazole, dithiocarbamate And derivatives such as tetramethylpiperidine.

(3) Binder Resin As the binder resin constituting the charge transport layer, various resins conventionally used for the photosensitive layer can be used.
For example, polycarbonate resin, polyester resin, polyarylate resin, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene , Ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, ionomer, vinyl chloride-vinyl acetate copolymer, alkyd resin, polyamide, polyurethane, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, Thermosetting resins such as polyether resins, silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, other cross-linkable thermosetting resins, epoxy acrylate, urethane acrylate, etc. Resin butter, and the like can be used.
In addition, these binder resins can be used alone or in combination of two or more.

(4) Film thickness In addition, the film thickness of the charge transport layer is generally preferably set to a value in the range of 5 to 50 μm. This is because when the thickness of the charge transport layer is less than 5 μm, it may be difficult to apply uniformly. On the other hand, when the thickness of the charge transport layer exceeds 50 μm, the mechanical strength may decrease. Therefore, it is more preferable to set the value within the range of 10 to 40 μm.

6). Image Forming Apparatus An image forming apparatus equipped with the electrophotographic photosensitive member of the present invention can be configured as, for example, a copying machine 30 as shown in FIG. The copying machine 30 includes an image forming unit 31, a paper discharge unit 32, an image reading unit 33, and a document feeding unit 34. The image forming unit 31 further includes an image forming unit 31a and a paper feeding unit 31b. In the illustrated example, the document feeding unit 34 includes a document placing tray 34a, a document feeding mechanism 34b, and a document discharge tray 34c, and the document placed on the document placing tray 34a. Is fed to the image reading position P by the document feeding mechanism 34b and then discharged to the document discharge tray 34c.
Then, when the original is sent to the original reading position P, the image reading unit 33 reads the image on the original using the light from the light source 33a. That is, an image signal corresponding to the image on the document is formed using an optical element 33b such as a CCD.
On the other hand, recording sheets (hereinafter simply referred to as “sheets”) S stacked on the sheet feeding unit 31b are sent one by one to the image forming unit 31a. The image forming unit 31a is provided with a photoconductive drum 41 as an image carrier. Further, around the photoconductive drum 41, a charger 42, an exposure unit 43, a developing unit 44, and a transfer roller. 45 is arranged along the rotation direction of the photosensitive drum 41.

Among these components, the photosensitive drum 41 is rotationally driven in the direction indicated by the solid line arrow in the drawing, and the surface thereof is uniformly charged by the charger 42. Thereafter, an exposure process is performed on the photosensitive drum 41 by the exposure device 43 based on the above-described image signal, and an electrostatic latent image is formed on the surface of the photosensitive drum 41.
Based on the electrostatic latent image, the developing unit 44 attaches toner and develops it, thereby forming a toner image on the surface of the photosensitive drum 41. The toner image is transferred as a transfer image onto the sheet S conveyed to the nip portion between the photosensitive drum 41 and the transfer roller 45. Next, the sheet S to which the transferred image is transferred is conveyed to the fixing unit 47 and a fixing process is performed.

  Further, the sheet S after fixing is sent to the paper discharge unit 32. However, when performing post-processing (for example, stapling processing), the paper S is sent to the intermediate tray 32a and then post-processed. Is done. Thereafter, the sheet S is discharged to a discharge tray portion (not shown) provided on the side surface of the image forming apparatus. On the other hand, when no post-processing is performed, the sheet S is discharged to a discharge tray 32b provided below the intermediate tray 32a. The intermediate tray 32a and the paper discharge tray 32b are configured as a so-called in-body paper discharge unit.

[Second Embodiment]
The second embodiment of the present invention is a method for producing a laminated electrophotographic photosensitive member in which a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate, and includes the following steps ( A method for producing a laminated electrophotographic photoreceptor, comprising a) to (f).
(A) A step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal.
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dropping a titanyl phthalocyanine solution into a poor solvent to obtain a wet cake.
(D) A step of washing the wet cake using a washing solvent.
(E) A step of heating and stirring the washed wet cake in a non-aqueous solvent to obtain a Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) aging characteristics.
(A) Initial characteristics The Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ±. There are peaks at 0.2 ° = 7.4 ° and 9.6 °, respectively, and the peak intensity at Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and Bragg angle 2θ When the peak intensity at ± 0.2 ° = 9.6 ° is Y (cps), the value of X / Y (−) is a value less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days (f) A Y-type titanyl phthalocyanine crystal and a binder resin are dispersed in a solvent mainly containing at least one compound selected from alkyl acetate, alkylene glycol monoalkyl ether and alcohol. And a step of producing a charge generation layer coating solution.
Hereinafter, the content already described in the first embodiment will be omitted as appropriate, and a method for manufacturing a multilayer electrophotographic photosensitive member according to the second embodiment will be described.

1. Step (a)
Step (a) is a step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal.
A method for producing a titanyl phthalocyanine compound is not particularly limited, and a conventional method for producing a titanyl phthalocyanine compound can be used.
Here, the manufacturing method of the titanyl phthalocyanine compound represented by Formula (3) mentioned above is demonstrated as an example.

(1) Reaction formula It is preferable that the synthesis | combination of the titanyl phthalocyanine compound in a process (a) is reaction of a phthalonitrile or diiminoisoindoline, and a titanium alkoxide.
More specifically, as shown in Reaction Formula (1), phthalonitrile such as o-phthalonitrile represented by Formula (4), and titanium alkoxide such as titanium tetrabutoxide represented by Formula (5); Or diiminoisoindoline such as 1,3-diiminoisoindoline represented by formula (6) and titanium tetrabutoxide represented by formula (5) as shown in reaction formula (2) It is preferable to produce a titanyl phthalocyanine compound represented by the formula (3) by reacting with a titanium alkoxide such as

(2) Addition amount Further, the addition amount of titanium alkoxide to the above-mentioned phthalonitrile or diiminoisoindoline is set to a value within the range of 0.325 to 1 mol with respect to 1 mol of phthalonitrile or diiminoisoindoline. Is preferred.
The reason for this is that by carrying out the synthesis reaction at such an addition ratio, a specific Y-type titanyl phthalocyanine crystal can be obtained more efficiently through the subsequent steps.
That is, when the amount of titanium alkoxide added is less than 0.325 mol, phthalonitrile or diiminoisoindoline may remain without reacting. On the other hand, when the amount of titanium alkoxide added exceeds 1 mol, an excess amount of titanium alkoxide tends to remain.
Therefore, it is more preferable that the amount of titanium alkoxide added to phthalonitrile or diiminoisoindoline is a value within the range of 0.325 to 0.75 mol per mol of phthalonitrile or diiminoisoindoline. More preferably, the value is within the range of 375 to 0.625 mol.

(3) Urea compound Moreover, it is preferable to perform reaction represented by Reaction Formula (1) and (2) mentioned above in presence of a urea compound. The reason for this is that by using the titanyl phthalocyanine compound produced in the presence of the urea compound, the interaction between the urea compound and the titanium alkoxide is exhibited, so that a specific Y-type titanyl phthalocyanine crystal can be efficiently obtained. Because.
That is, this interaction means that the ammonia produced by the reaction between the urea compound and the titanium alkoxide further forms a complex with the titanium alkoxide, and this substance is a reaction represented by the reaction formulas (1) and (2). It is an action to promote. And a specific Y type titanyl phthalocyanine crystal | crystallization can be efficiently manufactured by making a raw material react with such a promotion effect | action.

(3) -1 types The urea compounds used in the reaction formulas (1) and (2) are urea, thiourea, O-methylisourea sulfate, O-methylisourea carbonate, and O-methylisourea hydrochloric acid. It is preferably at least one member of the group consisting of salts.
The reason for this is that by using such a urea compound as the urea compound in the reaction formulas (1) and (2), ammonia generated in the course of the reaction more efficiently forms a complex with the titanium alkoxide, and the substance This is for further promoting the reactions represented by the reaction formulas (1) and (2).
That is, the ammonia produced by the reaction between the titanium alkoxide as the raw material and the urea compound forms a complex compound with the titanium alkoxide more efficiently. Therefore, this complex compound further promotes the reactions represented by the reaction formulas (1) and (2).
It has been found that such a complex compound is likely to be produced specifically when reacted under a high temperature condition of 180 ° C. or higher. Therefore, among nitrogen-containing compounds having a boiling point of 180 ° C. or higher, for example, quinoline (boiling point: 237.1 ° C.), isoquinoline (boiling point: 242.5 ° C.), or a mixture thereof (weight ratio 10:90 to 90:10) It is more effective to implement in.
Therefore, it is more preferable to use urea among the above-described urea compounds because ammonia as a reaction accelerator and a complex compound resulting therefrom are more easily generated.

(3) -2 Addition amount The addition amount of the urea compound used in the reaction formulas (1) and (2) is 0.5-3 mol with respect to 1 mol of phthalonitrile or diiminoisoindoline. A value within the range is preferable.
This is because the above-described action of the urea compound can be more efficiently exhibited by setting the addition amount of the urea compound within the range.
Therefore, it is more preferable that the amount of the urea compound added is a value within the range of 1.1 to 2.5 mol per mol of phthalonitrile or diiminoisoindoline, More preferably, the value is within the range.

(4) Solvent Further, examples of the solvent used in the reaction formulas (1) and (2) include hydrocarbon solvents such as xylene, naphthalene, methylnaphthalene, tetralin, and nitrobenzene, dichlorobenzene, trichlorobenzene, and dibromobenzene. , And halogenated hydrocarbon solvents such as chloronaphthalene, alcohol solvents such as hexanol, octanol, decanol, benzyl alcohol, ethylene glycol, and diethylene glycol, cyclohexanone, acetophenone, 1-methyl-2-pyrrolidone, and 1,3- One or two or more arbitrary combinations of the group consisting of ketone solvents such as dimethyl-2-imidazolidinone, amide solvents such as formamide and acetamide, and nitrogen-containing solvents such as picoline, quinoline and isoquinoline are listed. I can get lost.
In particular, in the case of a nitrogen-containing compound having a boiling point of 180 ° C. or higher, for example, quinoline or isoquinoline, the ammonia produced by the reaction of titanium alkoxide as a raw material with a urea compound is more efficiently complexed with titanium alkoxide or the like. It is a suitable solvent because it easily forms a compound.

(5) Reaction temperature Moreover, it is preferable to make reaction temperature in Reaction formula (1) and (2) into 150 degreeC or more high temperature. This is because when the reaction temperature is less than 150 ° C., particularly 135 ° C. or less, the titanium alkoxide as the raw material reacts with the urea compound and it is difficult to form a complex compound. Therefore, it becomes difficult for such a complex compound to further promote the reaction represented by the reaction formulas (1) and (2), and it becomes difficult to efficiently produce a specific Y-type titanyl phthalocyanine crystal. It is.
Therefore, the reaction temperature in the reaction formulas (1) and (2) is more preferably set to a value within the range of 180 to 250 ° C, and further preferably set to a value within the range of 200 to 240 ° C.

(6) Reaction time The reaction time in the reaction formulas (1) and (2) depends on the reaction temperature, but is preferably in the range of 0.5 to 10 hours. The reason for this is that when the reaction time is less than 0.5 hours, the titanium alkoxide as the raw material reacts with the urea compound, making it difficult to form a complex compound. Therefore, it becomes difficult for such a complex compound to further promote the reaction represented by the reaction formulas (1) and (2), and it becomes difficult to efficiently produce a specific Y-type titanyl phthalocyanine crystal. It is. On the other hand, when the reaction time exceeds 10 hours, it is economically disadvantageous or the produced complex compound may be reduced.
Therefore, it is more preferable to set the reaction time in the reaction formulas (1) and (2) to a value in the range of 0.6 to 3.5 hours, and to a value in the range of 0.8 to 3 hours. Further preferred.

(7) Crude Crystallization Next, the produced titanyl phthalocyanine compound is added to a water-soluble organic solvent, and the mixture is stirred for a certain period of time under heating, and then the liquid is removed for a certain period of time under temperature conditions lower than the stirring process. It is preferable to perform a stabilization treatment by allowing to stand to obtain a crude titanyl phthalocyanine crystal.
Examples of the water-soluble organic solvent used at this time include alcohols such as methanol, ethanol, and isopropanol, N, N-dimethylformamide, N, N-dimethylacetamide, propionic acid, acetic acid, N-methylpyrrolidone, and 1 type, or 2 or more types, such as ethylene glycol, is mentioned. Note that a water-insoluble organic solvent may be added to the water-soluble organic solvent in a small amount.

Moreover, although the conditions of the stirring process mentioned above are not specifically limited, It is preferable to perform the stirring process for about 1-3 hours on the fixed temperature conditions of about 70-200 degreeC temperature range.
Furthermore, the conditions for the stabilization treatment after the stirring treatment are not particularly limited, but are about 10 to 50 ° C., particularly preferably about 5 to 15 hours under a constant temperature condition of about 23 ± 1 ° C. It is preferable to stabilize by standing.

2. Step (b)
Step (b) is a step of performing acid treatment on the crude titanyl phthalocyanine crystal to obtain a titanyl phthalocyanine solution.
The reason for carrying out the acid treatment in this way is to dissolve the crude titanyl phthalocyanine crystal with respect to the acid, thereby sufficiently decomposing impurities derived from the material substance and the like remaining when the titanyl phthalocyanine compound is produced. Because.
The acid to be used is preferably at least one acid selected from the group consisting of concentrated sulfuric acid, trifluoroacetic acid and sulfonic acid.
This is because such an acid can decompose the above-mentioned impurities more effectively, while the decomposition of the titanyl phthalocyanine compound can be effectively suppressed.
Moreover, with such an acid, it is because the component derived from these acids can be easily removed by the washing | cleaning mentioned later after an acid treatment.

Further, the temperature of the acid used in the acid treatment is set to a value of 15 ° C. or more.
This is because a specific Y-type titanyl phthalocyanine crystal can be produced more efficiently by setting the acid temperature in the acid treatment to a value within such a range.
That is, when the temperature of the acid is less than 15 ° C., the Y-type titanyl phthalocyanine crystal thus produced may not be sufficiently increased in the degree of alpha conversion even under a predetermined condition. Because there is. Therefore, it is difficult to efficiently obtain the specific Y-type titanyl phthalocyanine crystal described in the first embodiment. On the other hand, when the acid temperature is excessively high, the titanyl phthalocyanine compound itself may be decomposed.
Therefore, the temperature of the acid used in the acid treatment is more preferably set to a value within the range of 20 to 40 ° C, and further preferably set to a value within the range of 25 to 35 ° C.

Next, the relationship between the acid temperature in the acid treatment and X / Y (−) (degree of α conversion) when the Y-type titanyl phthalocyanine crystal is stirred under predetermined conditions will be described with reference to FIG.
In FIG. 5, a characteristic curve is shown in which the horizontal axis indicates the acid temperature (° C.) and the vertical axis indicates the degree of alphaization (−) after stirring.
It should be noted that the value of the degree of α-ization at the initial stage in the Y-type titanyl phthalocyanine crystal, that is, the value of the degree of alpha-ization at the stage before stirring under a predetermined condition was all less than 0.3.
As understood from the characteristic curve, when the acid temperature is in the range of less than 15 ° C., the value of the degree of agitation after stirring increases only slightly. Therefore, it can be seen that when the acid temperature is less than 15 ° C., it is difficult to set the value of the degree of α after stirring to a value of 0.5 or more. On the other hand, when the temperature of the acid is in the range of 15 ° C. or higher, the value of the degree of agitation after stirring starts to increase rapidly with the increase, and it can be seen that it can surely take a value of 0.5 or higher. .
Therefore, by setting the acid temperature in the acid treatment to 15 ° C. or more, the α-degree of the Y-type titanyl phthalocyanine crystal when the Y-type titanyl phthalocyanine crystal is stirred under a predetermined condition is surely 0.5 or more. It can be seen that the value of This means that a specific Y-type titanyl phthalocyanine crystal can be stably produced by setting the acid temperature in the acid treatment to a value of 15 ° C. or higher.

3. Step (c)
Step (c) is a step in which a titanyl phthalocyanine solution is dropped into a poor solution to obtain a wet cake.
The reason for carrying out the dripping in this way is that the titanyl phthalocyanine solution can be dripped into the poor solvent, thereby making it possible to more effectively clean the impurities in the subsequent steps.
That is, since the wet cake of the titanyl phthalocyanine compound deposited by dripping becomes an amorphous shape having a large surface area, impurities can be effectively removed in a later step.
Moreover, it is preferable that the poor solvent to be used is water.
This is because, in the case of water, the titanyl phthalocyanine compound can be precipitated more easily from the viewpoint of polarity and temperature control.
Therefore, the surface area in the wet cake of the precipitated titanyl phthalocyanine compound can be increased, and impurities can be removed more effectively.
As other poor solvents, methanol, ethanol, a mixed solvent of methanol and water, a mixed solvent of ethanol and water, or the like can be used.
In addition, although the temperature of a poor solvent changes with kinds of poor solvent to be used, generally it is preferable to set it in the 0-20 degreeC range.

4). Step (d)
Step (d) is a step of washing the wet cake using a washing solvent.
That is, the impurities can be effectively removed by cleaning with a cleaning solvent after making the impurities easy to remove by the step (c) described above.

Moreover, it is preferable to use alcohol as a cleaning solvent.
This is because, in the case of alcohol, impurities in a state decomposed by the acid treatment in the step (b) can be effectively eluted and removed.
Examples of the alcohol include methanol, ethanol, 1-propanol and the like.

5. Step (e)
Step (e) is a step of heating and stirring the washed wet cake in a non-aqueous solvent to obtain the specific Y-type titanyl phthalocyanine crystal described in detail in the first embodiment.
That is, the crystal form can be converted to the Y form by heating and stirring the washed wet cake in a non-aqueous solvent.
In addition, it is preferable to disperse | distribute the heating stirring mentioned above in a non-aqueous solvent in the state where water existed, and to stir at 30-70 degreeC for 5 to 40 hours.
Examples of the non-aqueous solvent include halogen solvents such as chlorobenzene and dichloromethane.

6). Step (f)
Step (f) is a step of manufacturing a charge generation layer coating solution by dispersing Y-type titanyl phthalocyanine crystals and a binder resin in a solvent.
That is, a Y-type titanyl phthalocyanine crystal and a binder resin are added to a solvent, and dispersed and mixed using, for example, a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser, etc., to obtain a coating solution. preferable.
More specifically, it is preferable to prepare a coating solution having a solid content concentration of 1 to 7% by weight. This is because when the solid content concentration of the coating liquid is less than 1% by weight, film defects may occur. On the other hand, when the solid content concentration of the coating liquid exceeds 7% by weight, layer unevenness occurs. This is because it tends to occur and it may be difficult to form a thin film having a uniform thickness as an electrophotographic photosensitive member.

Further, the solvent is characterized in that it is a solvent mainly comprising at least one compound selected from alkyl acetate, alkylene glycol monoalkyl ether and alcohol.
This is because compounds other than these compounds, for example, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane, chloroform and carbon tetrachloride. When using solvents such as halogenated hydrocarbons such as chlorobenzene, ketones such as acetone, methyl ethyl ketone, cyclohexanone, esters such as ethyl acetate, methyl acetate, dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide, etc. This is because a specific Y-type titanyl phthalocyanine crystal may easily undergo a crystal transition to the α-type in the charge generation layer coating solution.
In addition, even when ethers other than alkylene glycol monoalkyl ether, for example, dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dioxane, dioxolane, etc. are used as solvents, the crystal transition to α-type is similarly performed. It is because it may become easy to do.

In addition, from the need to improve the solubility of the binder resin, when using tetrahydrofuran as the solvent, the total amount of the solvent mainly composed of alkyl acetate, alkylene glycol monoalkyl ether, alcohol, etc., Tetrahydrofuran may be contained at a value within the range of 10% by weight or less.
The reason for this is to improve the solubility of the poorly soluble binder resin while minimizing the crystal transition of the specific Y-type titanyl phthalocyanine crystal by containing tetrahydrofuran in such a range. It is because it can do.
Therefore, when tetrahydrofuran is contained in the solvent, it is more preferably contained at a value within the range of 0.1 to 8% by weight with respect to the total amount of the solvent, and the range of 0.1 to 5% by weight. It is further more preferable to make it contain by the value of the inside.

7). Application and Drying Step The application step and the drying step are steps for forming the charge generation layer by applying and drying the obtained coating solution for charge generation layer on the substrate.
That is, it is also preferable to apply the charge generation layer coating solution directly on the substrate, or to apply it indirectly via an intermediate layer.
As a coating method, it is preferable to use, for example, a spin coater, an applicator, a spray coater, a bar coater, a dip coater, a doctor blade, etc. in order to form a charge generation layer having a uniform thickness.

  Moreover, after an application | coating process, it is preferable to make it dry at the drying temperature of 60 to 150 degreeC using a high temperature dryer, a vacuum dryer, etc., for example. This is because when the drying temperature is less than 60 ° C., the drying time becomes excessively long, and it may be difficult to efficiently form a charge generation layer having a uniform thickness. is there. On the other hand, when the drying temperature exceeds 150 ° C., the charge generation layer may be thermally decomposed.

  The charge transport layer and the intermediate layer are also formed by dissolving the constituent materials described in the first embodiment in a generally used solvent to produce a coating solution, and coating and drying the coating solution. can do.

Hereinafter, based on an Example, this invention is demonstrated concretely.
[Example 1]
1. Production of titanyl phthalocyanine compound In a flask substituted with argon, 25 g (0.195 mol) of o-phthalonitrile, 28 g (0.0822 mol) of titanium tetrabutoxide, 300 g of quinoline, and 20 g (0.33 mol) of urea were added. In addition, the temperature was raised to 150 ° C. with stirring (addition amount of titanium tetrabutoxide to 1 mol of o-phthalonitrile: 0.422 mol, addition amount of urea to 1 mol of o-phthalonitrile: 1.7 mol).
Next, the temperature of the system was raised to 215 ° C. while distilling off the vapor generated from the reaction system, and the mixture was further stirred for 2 hours while maintaining this temperature.
Then, after the reaction is completed, when the reaction mixture is cooled to 150 ° C., the reaction mixture is taken out of the flask, filtered through a glass filter, and the resulting solid is washed successively with N, N-dimethylformamide and methanol and then vacuum-dried. As a result, 25 g of a blue-violet solid was obtained.

2. Production of Y-type titanyl phthalocyanine crystals (1) Pre-pigmentation treatment 15 g of the blue-purple solid obtained in the production of the above-mentioned titanyl phthalocyanine compound was added to 100 ml of N, N-dimethylformamide and stirred at 130 ° C. The mixture was stirred for 2 hours after heating.
Next, the heating was stopped when 2 hours passed, and further the stirring was stopped when the temperature was cooled to 23 ± 1 ° C. In this state, the liquid was allowed to stand for 12 hours for stabilization treatment. The stabilized supernatant was filtered off with a glass filter, and the resulting solid was washed with methanol and then vacuum dried to obtain 9.83 g of a crude crystal of a titanyl phthalocyanine compound.

(2) Pigmentation treatment 5 g of the crude crystals of titanyl phthalocyanine obtained by the above-mentioned pigmentation pretreatment were added to 100 ml of 97% concentrated sulfuric acid and dissolved. The acid treatment was performed at 30 ° C. for 1 hour.
Next, this solution was added dropwise to 5 liters of pure water under ice cooling at 10 ml / min, stirred for 15 minutes at around 23 ± 1 ° C., and then allowed to stand for 30 minutes. The solution was then filtered through a glass filter to obtain a wet cake.
Subsequently, the obtained wet cake was suspended and washed in methanol until the washing solution became neutral, and the washed methanol was filtered through a glass filter.
Next, the washed wet cake was dispersed in 200 ml of chlorobenzene in a state where water was present without being dried, and the mixture was heated and stirred at 50 ° C. for 10 hours.
Crystals obtained by filtering the supernatant with a glass filter were vacuum-dried at 50 ° C. for 5 hours to obtain 4.5 g of unsubstituted titanyl phthalocyanine crystals (blue powder) represented by the formula (3). .

3. Evaluation of titanyl phthalocyanine crystal (1) Immediately after production A Cukα characteristic X-ray diffraction spectrum of a titanyl phthalocyanine crystal immediately after production was measured.
That is, 0.3 g of the obtained titanyl phthalocyanine crystal was filled in a sample holder of an X-ray diffractometer (RINT1100, manufactured by Rigaku Corporation) and measured. The obtained spectrum chart has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° and a clear peak at 9.6 °. Was confirmed to be a Y-type crystal. Furthermore, a peak at 24.2 °, which is one of the characteristics of the Y-type crystal, could be confirmed.
The measurement conditions were as follows.
X-ray tube: Cu
Tube voltage: 40 kV
Tube current: 30 mA
Start angle: 3.0 °
Stop angle: 40.0 °
Scanning speed: 10 ° / min

  The degree of alpha conversion was calculated from the peak intensities at Bragg angles 2θ ± 0.2 ° = 7.4 ° and 9.6 °. The obtained results are shown in Table 2. In addition, the β transition in Table 2 was evaluated by whether or not it had a peak at a Bragg angle 2θ ± 0.2 ° = 26.2 ° in the obtained spectrum chart (having a peak: x, peak Do not have: ○).

(2) Evaluation after stirring under predetermined conditions In addition, Cukα characteristic X-ray diffraction spectra were also measured on titanyl phthalocyanine crystals after stirring under predetermined conditions.
That is, 0.3 g of titanyl phthalocyanine crystal immediately after production was dispersed in 5 g of tetrahydrofuran and roll milled under conditions of a temperature of 23 ± 1 ° C. and a relative humidity of 50-60% for 10 days in a closed system at 60 rpm. It was.
Next, tetrahydrofuran is removed, the sample holder of an X-ray diffractometer (RINT1100 manufactured by Rigaku Corporation) is filled, and measurement is performed in the same manner as in the case of the titanyl phthalocyanine crystal immediately after production, and the calculation of the degree of α conversion and β transition was evaluated. The obtained results are shown in Table 2.

4). Production of electrophotographic photosensitive member (1) Formation of intermediate layer Using a bead mill, titanium oxide (MT-02, alumina, silica, surface-treated with silicone, number average primary particle size is 10 nm (manufactured by Teika)) 250 parts by weight Original copolymerized polyamide resin CM8000 (manufactured by Toray) 100 parts by weight, 1000 parts by weight of methanol as a solvent, and 250 parts by weight of n-butanol are mixed and dispersed for 5 hours, and further filtered through a 5 micron filter. An intermediate layer coating solution was prepared.
Next, an intermediate layer coating solution is applied by dipping the aluminum substrate (supporting substrate) having a diameter of 30 mm and a length of 238.5 mm at one end at a rate of 5 mm / sec with the one end of the aluminum substrate (supporting substrate) facing up. did. Then, the hardening process was performed on 130 degreeC and the conditions for 30 minutes, and the intermediate layer with a film thickness of 2 micrometers was formed.

(2) Formation of charge generation layer Next, using a bead mill, 200 parts by weight of Y-type titanyl phthalocyanine crystal produced as described above as a charge generation agent, 100 parts by weight of polyvinyl butyral resin as a binder resin, and acetic acid as a solvent 4000 parts by weight of ethyl and 4000 parts by weight of propylene glycol monomethyl ether were mixed and dispersed for 2 hours to obtain a coating solution for the charge generation layer. The obtained coating solution is filtered through a 3 micron filter, and then applied onto the above-described intermediate layer by dip coating, and dried at 80 ° C. for 5 minutes to form a charge generation layer having a thickness of 0.2 μm. did.

(3) Formation of charge transport layer Next, 55 parts by weight of a hydrazone compound (HTM-1) represented by the following formula (7) as a hole transport agent and 5 wt. Parts, 10 parts by weight of dibutylhydroxytoluene as an antioxidant, 60 parts by weight of a polycarbonate resin (Resin-1) represented by the following formula (8) having a viscosity average molecular weight of 20,000 as a binder resin, and a viscosity average molecular weight After containing 40 parts by weight of a polycarbonate resin (Resin-2) represented by the following formula (9) of 50,000, 310 parts by weight of tetrahydrofuran as a solvent, and 310 parts by weight of toluene, the mixture was dispersed for 10 minutes. Thus, a charge transport layer coating solution was obtained.
The obtained charge transport layer coating solution was applied onto the charge generation layer in the same manner as the charge generation layer coating solution, and dried at 120 ° C. for 30 minutes to form a charge transport layer having a thickness of 20 μm. A photographic photoreceptor was prepared.
Table 1 shows differences in the manufacturing conditions of the multilayer electrophotographic photosensitive member in Example 1 and other examples and comparative examples described below.

5. Evaluation of electrical characteristics (1) Measurement of light potential The light potential of the obtained multilayer electrophotographic photosensitive member was measured.
That is, the obtained multilayer electrophotographic photosensitive member is mounted on a printer (Microline-22, manufactured by Oki Data Co., Ltd.) that employs a commercially available negative charge reversal development process, and a normal temperature and humidity environment (temperature: 25 ° C.). , Relative humidity: 50% Rh).
More specifically, after image formation is continuously performed on 10,000 sheets, the multilayer electrophotographic photosensitive member is charged so that the surface potential becomes −900 to −850 V to obtain a charging potential (V), and black The surface potential at the development position when a solid image was formed was defined as the bright potential (V). The obtained results are shown in Table 2. The measured light potential (V) was a negative value, but Table 2 shows the absolute value.

(2) Measurement of memory potential Further, the memory potential of the obtained multilayer electrophotographic photosensitive member was evaluated.
That is, the obtained multilayer electrophotographic photosensitive member is mounted on the same printer as described above, and after 10,000 images are continuously formed in the same environment, the first round (95 mm The long electrophotographic photosensitive member was subjected to exposure corresponding to a solid black image of 65 mm (exposed portion), and the remaining 30 mm was not exposed (non-exposed portion). Next, no exposure was performed on the entire laminated electrophotographic photosensitive member on the second round. Next, the surface potential V ₀ b (V) in the second turn of the portion corresponding to the exposed portion of the first turn and the surface potential V ₀ (V) in the second turn of the portion corresponding to the non-exposed portion of the first turn. If the measured absolute value │V ₀ -V ₀ b│ the potential difference (V) was calculated, and the memory potential (V). The obtained results are shown in Table 2.

6). Evaluation of titanyl phthalocyanine crystal after formation of charge generation layer (1) Immediately after dissolution The Cukα characteristic X-ray diffraction spectrum of the titanyl phthalocyanine crystal immediately after dissolution of the formed charge generation layer in tetrahydrofuran was measured.
That is, 0.3 g of the charge generation layer was peeled from the substrate, dissolved and dispersed in 5 g of tetrahydrofuran, and the titanyl phthalocyanine crystal contained in the charge generation layer was taken out.
Next, tetrahydrofuran was removed, and 0.3 g of the obtained titanyl phthalocyanine crystal was filled into a sample holder of an X-ray diffractometer (RINT1100, manufactured by Rigaku Corporation), and the same as in the case of the titanyl phthalocyanine crystal immediately after production. In addition to the measurement, the degree of alpha conversion and the evaluation of beta metastasis were performed. The obtained results are shown in Table 2.

(2) Evaluation after stirring in tetrahydrofuran In addition, the charge generation layer was dissolved and dispersed in tetrahydrofuran as described above, and the Cukα characteristic X-ray diffraction spectrum was measured on the titanyl phthalocyanine crystal after stirring for 10 days. It was.
That is, after dissolving and dispersing the charge generation layer in tetrahydrofuran, 0.3 g of the extracted titanyl phthalocyanine crystal was dispersed in 5 g of tetrahydrofuran and sealed under a condition of a temperature of 23 ± 1 ° C. and a relative humidity of 50 to 60%. The roll mill was carried out at 60 rpm for 10 days.
Next, tetrahydrofuran was removed, and 0.3 g of the obtained titanyl phthalocyanine crystal was filled in a sample holder of an X-ray diffractometer (RINT1100 manufactured by Rigaku Corporation), and the same as in the case of the titanyl phthalocyanine crystal immediately after production. In addition to the measurement, the degree of alpha conversion and the evaluation of beta metastasis were performed. The obtained results are shown in Table 2.

[Examples 2-3]
In Examples 2 to 3, a laminated electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the acid temperature in the acid treatment was changed to 20 and 15 ° C., respectively, when the Y-type titanyl phthalocyanine crystal was produced. And evaluated. The obtained results are shown in Table 2.

[Example 4]
In Example 4, when producing a titanyl phthalocyanine compound, 25 g (0.195 mol) of o-phthalonitrile as a raw material was changed to 28.3 g (0.195 mol) of diiminoisoindoline. A multilayer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1. The obtained results are shown in Table 2.

[Example 5]
In Example 5, when forming the charge generation layer, the laminated electrophotographic photosensitive member was the same as in Example 1 except that 4000 parts by weight of propylene glycol monomethyl ether as a solvent was changed to 4000 parts by weight of 1-propanol. The body was manufactured and evaluated. The obtained results are shown in Table 2.

[Example 6]
In Example 6, a multilayer electrophotographic photosensitive member was produced in the same manner as in Example 1 except that, when the charge generation layer was formed, 4000 parts by weight of ethyl acetate as a solvent was changed to 1-propanol. evaluated. The obtained results are shown in Table 2.

[Comparative Examples 1-2]
In Comparative Examples 1 and 2, when producing the Y-type titanyl phthalocyanine crystal, the acid temperature in the acid treatment was changed to 10 and 5 ° C. as shown in Table 1, respectively, as in Example 1. A laminated electrophotographic photosensitive member was manufactured and evaluated. The obtained results are shown in Table 2.

[Comparative Example 3]
In Comparative Example 3, when the titanyl phthalocyanine compound was produced, 28 g (0.0822 mol) of titanium tetrabutoxide as a raw material was changed to 15.6 g (0.0822 mol) of titanium tetrachloride. In the same manner as in Example 1, a laminated electrophotographic photosensitive member was produced and evaluated. The obtained results are shown in Table 2.

[Comparative Example 4]
In Comparative Example 4, when the Y-type titanyl phthalocyanine crystal was produced, the addition amount of titanium tetrabutoxide was 16.6 g (0.049 mol) (addition amount of titanium tetrabutoxide to 1 mol of o-phthalonitrile: 0.0. A laminated electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the acid temperature in the acid treatment was changed to 5 ° C. The obtained results are shown in Table 2.

According to the multilayer electrophotographic photosensitive member of the present invention, the optical characteristics of the Y-type titanyl phthalocyanine crystal as the charge generating agent are regulated within a predetermined range, and the Y-type titanyl phthalocyanine crystal is kept under a predetermined environment for a predetermined period. The change in the optical properties in the case of scenting is also defined quantitatively, thereby effectively suppressing the crystal transition of the Y-type titanyl phthalocyanine crystal, while making its charge generation ability and dispersibility more effective and stable. It has become possible to demonstrate.
As a result, it is possible to stably and easily obtain a multilayer electrophotographic photoreceptor capable of effectively suppressing the occurrence of exposure memory even when images are continuously formed. It was.
Therefore, such a multilayer electrophotographic photosensitive member is expected to contribute significantly to improving electrical characteristics and stabilizing quality in various image forming apparatuses such as copying machines and printers.

(A)-(c) is a figure provided in order to demonstrate the structure of a laminated type photosensitive layer. It is a figure provided in order to demonstrate the relationship between the alpha-ization degree after stirring, and a memory potential. It is a figure provided in order to demonstrate the relationship between the alpha-ization degree after stirring after forming a charge generation layer, and a memory potential. FIG. 2 is a diagram provided for explaining an image forming apparatus equipped with a multilayer electrophotographic photosensitive member of the present invention. It is a figure provided in order to demonstrate the relationship between the temperature of an acid, and the gelatinization degree after stirring.

Explanation of symbols

12: Base 20: Laminated electrophotographic photosensitive member 20 ′: Laminated electrophotographic photosensitive member 20 ″: Laminated electrophotographic photosensitive member 22: Charge transport layer 24: Charge generating layer 25: Intermediate layer 31: Image forming unit 31a : Image forming unit 31 b: Paper feeding unit 32: Paper discharge unit 33: Image reading unit 33 a: Light source 33 b: Optical element 34: Document feeding unit 34 a: Document loading tray 34 b: Document feeding mechanism 34 c: Document discharge tray 41 : Photosensitive drum 42: Charger 43: Exposure source 44: Developer 45: Transfer roller

Claims (8)

A laminated electrophotographic photosensitive member in which a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate,
Wherein the charge generating agent, Y type titanyl phthalocyanine crystal der having the following (A) initial characteristics and (B) aging characteristics,
A laminated electrophotographic photosensitive member obtained by a process including the following processes (a) to (e).
(A) Step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dripping the titanyl phthalocyanine solution into a poor solvent to obtain a wet cake
(D) A step of cleaning the wet cake using a cleaning solvent.
(E) The wet cake after washing is heated and stirred in a non-aqueous solvent to obtain a Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) aging characteristics: (A) Initial characteristics Y Type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ ± 0.2 ° = 7 .4 ° and 9.6 ° respectively, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps), and the Bragg angle 2θ ± 0.2. When the peak intensity at ° = 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days The (A) initial characteristic of the Y-type titanyl phthalocyanine crystal is characterized by having a peak at a Bragg angle 2θ ± 0.2 ° = 24.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, The multilayer electrophotographic photosensitive member according to claim 1.   3. The laminate according to claim 1, wherein a Y-type titanyl phthalocyanine crystal obtained by dissolving and dispersing the charge generation layer in tetrahydrofuran has the (A) initial characteristic and (B) time-dependent characteristic. Type electrophotographic photoreceptor.   As a further requirement of the (B) temporal characteristics, the Y-type titanyl phthalocyanine crystal has a peak at a Bragg angle 2θ ± 0.2 ° = 26.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source. The multilayer electrophotographic photosensitive member according to claim 1, wherein the multilayer electrophotographic photosensitive member is not present. A method for producing a laminated electrophotographic photosensitive member, wherein a charge generation layer containing a charge generation agent and a charge transport layer are provided on a substrate,
A method for producing a laminated electrophotographic photosensitive member, comprising the following steps (a) to (e) :
(A) A step of synthesizing a titanyl phthalocyanine compound to obtain a crude titanyl phthalocyanine crystal.
(B) A step of obtaining a titanyl phthalocyanine solution by performing an acid treatment for dissolving the crude titanyl phthalocyanine crystal in an acid having a temperature of 15 ° C. or higher.
(C) A step of dripping the titanyl phthalocyanine solution into a poor solvent to obtain a wet cake.
(D) A step of washing the wet cake with a washing solvent.
(E) A step of heating and stirring the wet cake after washing in a non-aqueous solvent to obtain a Y-type titanyl phthalocyanine crystal having the following (A) initial characteristics and (B) aging characteristics.
(A) Initial characteristics The Y-type titanyl phthalocyanine crystal has a maximum peak at a Bragg angle 2θ ± 0.2 ° = 27.2 ° in an X-ray diffraction spectrum using Cu-kα as a radiation source, and a Bragg angle 2θ. ± 0.2 ° = 7.4 ° and 9.6 ° respectively have peaks, and the peak intensity at the Bragg angle 2θ ± 0.2 ° = 7.4 ° is X (cps). When the peak intensity at the Bragg angle 2θ ± 0.2 ° = 9.6 ° is Y (cps), the value of X / Y (−) is less than 0.3.
(B) Time-lapse characteristics When the Y-type titanyl phthalocyanine crystal is stirred under the following conditions, the value of X / Y (-) is a value of 0.5 or more.
Stirring solvent: tetrahydrofuran addition ratio: to 100 parts by weight of tetrahydrofuran,
6 parts by weight of Y-type titanyl phthalocyanine crystal Stirring means: Roll mill stirring speed: 60 rpm
Stirring temperature: 23 ± 1 ° C
Stirring time: 10 days   The synthesis of the titanyl phthalocyanine compound in the step (a) is a synthesis by reaction of phthalonitrile or diiminoisoindoline with titanium alkoxide, and the addition amount of the titanium alkoxide with respect to the phthalonitrile or diiminoisoindoline. 6. The method for producing a multilayer electrophotographic photosensitive member according to claim 5, wherein the value is within a range of 0.325 to 1 mol per mol of the phthalonitrile or diiminoisoindoline. In the synthesis of the titanyl phthalocyanine compound in the step (a), the urea compound is added at a value in the range of 0.5 to 3 mol with respect to 1 mol of the phthalonitrile or diiminoisoindoline. A method for producing a multilayer electrophotographic photosensitive member according to claim 6.   The method for producing a multilayer electrophotographic photosensitive member according to claim 5, wherein an alcohol is used as the cleaning solvent in the step (d).