JPH11218946A - Titanylphthalocyanine pigment dispersed liquid and electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the titanylphthalocyanine pigment dispersed liquid capable of forming the electrophotographic photoreceptor small in residual potential and good in use repetition characteristics and free from image defect and high in sensitivity and chargeability and to provide this electrophotographic photoreceptor. SOLUTION: The titanylphthalocyanine pigment dispersed liquid has a maximum peak at a Bragg angle (2θ) of 27.2±0.2 deg. and a second peak at 24.1±0.2 deg. in the X-ray diffraction spectra and a main spectral absorption peak in a wavelength of 790±20 nm and a second peak in 690-650 nm is not found.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dispersion of a titanyl phthalocyanine pigment used for producing an electrophotographic photosensitive member.

[0002]

2. Description of the Related Art Hitherto, titanyl phthalocyanine has been actively studied as a highly sensitive material sensitive to a semiconductor having an oscillation wavelength in near-infrared light.

[0003] In particular, a Y-type titanyl phthalocyanine having a maximum peak at 27.2 degrees, and among them, a crystal having a peak having the next magnitude of 9.5 degrees and a small peak from 6 to 8 degrees is a photon efficiency. Is close to 1 and is an extremely sensitive material (Japan Hardcopy)
89 'Transactions 103 (1989)).

However, various problems emerge when a pigment is actually dispersed to prepare a coating solution and a photoreceptor is manufactured. Some photoconductors have image defects such as spots, and some photoconductors have problems such as a decrease in sensitivity and a decrease in chargeability.

[0005] Many of these defects are more problematic in the prepared dispersion than the intrinsic properties of the pigment. When the inventors published Y-type titanyl phthalocyanine (the above document), the spectral absorption spectrum (measured as a coating film) was 630 nm.
It was introduced that those having peak components at around 790 nm, 700 nm, and 630 nm, and particularly those having the maximum peak at 850 nm were excellent. However, the dispersion used here was prepared with a recipe aiming to maintain the crystal form even after the dispersion, and in order to make the dispersion as gentle and uniform as possible, the amount of the binder as an insulator was larger than that of the pigment ( (2 times weight ratio), and the dispersion strength itself is kept low.

Therefore, in the X-ray diffraction spectrum, 9.5 degrees can be maintained as the second strongest peak even after dispersion, and in terms of performance, the initial sensitivity and the photon quantum efficiency show that the Y-type titanyl phthalocyanine does not have the original peak. It brings out excellent performance. Then, simply repeating the charging and the exposure in a model manner does not cause a serious problem.

However, in the photoreceptor actually used, in order to improve a mechanical problem such as peeling of a film at the time of repetitive copying, or a minute black spot-like image defect generated when a reversal development process is used, a charge layer is formed in a lower layer. There is no other choice but to provide an intermediate layer (underlayer) made of an insulator that blocks the injection.

In an actual photoreceptor to which such an intermediate layer has been added, the dispersion having a large binder / pigment ratio as described above has a disadvantage that the residual potential at the exposed portion in a repeated test is large. Particularly, recently, the performance of the photosensitive drum has been dramatically increased, and when the life of 100,000 copies is normally required, the increase in the residual potential becomes even more problematic.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dispersion of a titanyl phthalocyanine pigment which does not have the above-mentioned problems, and has a low residual potential when electrophotographic photosensitive members are produced, and has good repeated use characteristics. Another object of the present invention is to provide a photosensitive member having high sensitivity and high chargeability without image defects.

[0010]

The inventors of the present invention have conducted intensive studies on the mechanical strength of the dispersion, the concentration of the solvent, the binder, and the pigment. As a result, the increase in the potential can be prevented to some extent by simply reducing the binder under the aforementioned conditions. However, the dispersion tends to be insufficient and image defects remain. However, they have found that a dispersion in the following state can achieve the object of the present invention, and have reached the present invention.

The object of the present invention is achieved by adopting the following constitution.

(1) In the dispersion of the titanyl phthalocyanine pigment, the X-ray diffraction spectrum of the dispersion has a maximum peak at a Bragg angle (2θ) of 27.2 ± 0.2 °, and 24.1 ± 0.2. Each time has a second intensity peak,
A dispersion liquid of a titanyl phthalocyanine pigment, wherein a main peak of a spectral absorption spectrum is at 790 ± 20 nm and no sub-peak is observed at 690 nm to 650 nm.

(2) The peak intensity at which the X-ray diffraction spectrum appears over 9.5 ± 0.4 degrees of the Bragg angle (2θ) is 60% or less of the peak intensity at 24.1 ± 0.2 degrees;
The dispersion of the titanyl phthalocyanine pigment according to (1), wherein the dispersion does not have a clear peak from 6 to 8 degrees.

(3) The dispersion of the titanyl phthalocyanine pigment according to (1) or (2), wherein the titanyl phthalocyanine pigment is obtained via an acid paste treatment.

(4) X-ray diffraction measurement of the titanyl phthalocyanine pigment before dispersion leads to a Bragg angle (2θ) of 27.2 ±
It has a maximum peak at 0.2 degrees and 9.5 ± 0.4
The dispersion of titanyl phthalocyanine pigment according to (1), (2) or (3), which has a clear peak at 24.1 ± 0.2 degrees.

(5) The crystal before the dispersion of the titanyl phthalocyanine pigment has a Bragg angle (2θ) 2 by X-ray diffraction measurement.
It has a maximum peak at 7.1 ± 0.2 degrees, and 9.5 in addition.
It has clear peaks at ± 0.4 degrees and 24.1 ± 0.2 degrees, and peaks appearing from 6.9 to 7.6 degrees have only 1/10 or less of the maximum peak intensity. The dispersion of the titanyl phthalocyanine pigment according to any one of (1) to (4), which has a crystal form.

(6) The dispersion of the titanyl phthalocyanine pigment according to any one of (1) to (5), wherein the titanyl phthalocyanine pigment is synthesized via diiminoisoindoline.

(7) An electrophotographic photoreceptor produced using a dispersion of the titanyl phthalocyanine pigment according to any one of (1) to (6).

In the present invention, having no clear peak in the X-ray diffraction spectrum means that it is indistinguishable or has only 1/10 or less the intensity of the main peak excluding the background.

The present invention is a dispersion defined by X-ray diffraction and spectral absorption spectrum as described in the claims.
The value of the Bragg angle (2θ) in the X-ray diffraction peak measurement is
Unless otherwise specified, it has a tolerance of ± 0.2 degrees. Further, the second intensity peak described in (1) may be any second peak even if there is another peak having the same intensity.

The reason for paying attention to the peak intensity ratio between the spectral absorption spectrum and the X-ray diffraction spectrum is as follows.

Spectral Absorption Spectroscopy Organic photoreceptors for electrophotography, which are used in many fields today, transport a charge generating substance (CGM) which generates photocharges when irradiated with light and transports the generated charges. A charge transport material (CTM) is needed. In general, light impinges on a dye to form an excited ion pair, which in some cases splits to generate holes and photoelectrons. In order for the dye to have a high photoelectric conversion efficiency, it is necessary that the generated excited ion pairs be present to some extent without being immediately deactivated and emit photoelectrons and holes (see FIG. 1).

For this purpose, it is more advantageous to have some kind of molecular aggregate (aggregation) structure rather than a monomolecular structure. This is not a generally dissolved dye as a charge generating substance,
This is why organic pigments are dispersed.

A spectroscopic absorption spectrum is one of the scales representing the aggregation morphology, and the relationship between the aggregation structure of the long wavelength shift and the sensitivity has been reported in several documents (The 3rd study of 1991 by the Electrographic Society of Japan). Proceedings of the Society, 22 Akira Kinoshita (Konica)).

Reported at a conference (Japan Ha
rdcopy 89 'Transactions 103 (1989))
The peak of dispersion absorption of Y-type titanyl phthalocyanine is 85
At 0 nm, it seems to be significantly different from 790 nm ± 20 nm of the present invention.

However, in the present invention, 790 ± 2
The peak at 0 nm is originally the four peaks and shoulders (8
790 nm out of 50, 790, 700, and 630 nm)
Can be interpreted as the main thing. As will be described later, the X-ray diffraction shows that the long-term order of the crystal (appearing at a low-angle peak) is broken, but the short-term order of the crystal (appearing at a high-angle peak) does not change. Although the crystal of the present invention is subtly the same as the Y-type crystal reported in the strict sense of the report or a new crystal, the inventors have found that the sensitivity characteristics are almost the same, Are considered to be still in the broad category of Y-type crystals.

The dispersion of the present invention has a size of 690 to 650 nm.
Is characterized by no peak. Here, the peak is not a shoulder but a vertex having a lower point on both sides (see FIG. 2). As will be described later in Examples and Comparative Examples, depending on dispersion conditions, these 690 to 65
A peak may appear in a region of 0 nm. This peak corresponds to A having the maximum peak at 26.2 degrees in X-ray diffraction.
Type (Japan Hardcopy 89 '
103 (1989), which is considered to be a sub-peak at 680 nm which is found in the I-type in the naming of JP-A-62-67094 (JP-A-62-67094).

Y type is A type and B type (both are Japan Ha
Unlike rdcopy 89 ', the collection of treatises 103 (1989)), it is liable to be transformed into type A by a chemical or mechanical force in a metastable state. The transition to type A can be regulated by the appearance of a peak at 26.2 degrees (the maximum peak of type A). By focusing on the absorption, the transition can be controlled in association with the electrophotographic performance (see Example 5 and Comparative Example 6, the peak at 780 nm which shows the maximum in the spectral absorption spectrum of the A type is the 790 nm peak of the Y type of the present invention). It is not possible to determine the overlap with the peak).

X-ray Diffraction X-ray diffraction is a general measure for measuring the crystal form, and indicates the position of the peak and the intensity of the peak. When a mechanical shear is applied by dispersion, even if no crystal change occurs, the crystal gradually collapses, and as a result, the peak intensity decreases and finally becomes almost amorphous. In particular, it is easy to imagine that the long-term order (appearing at a low angle) of the crystal is more likely to collapse.

Based on the above, the relationship between the dispersion time of the Y-type crystal and the diffraction spectrum of the dispersion, which is listed in the examples of the present invention, shows that the baseline is affected by the effect of the binder in the diffraction spectrum. It can be seen that the shape of the peak is rounded due to the rise. Looking at the time course, the peak intensity decreases as the dispersion progresses, and all the peaks decrease, and fine peaks cannot be identified early. If only the peaks that can be distinguished are viewed in terms of their intensities, 9.
The peak intensity around 5 degrees is remarkably reduced. (Because the peak is low and rounded, the peak position at 9.5 degrees can cover the error range within ± 0.2 degrees before dispersion, but after dispersion, If the range of ± 0.4 degrees is not defined, the range of the error is covered, and it cannot be said that the peak intensity was sufficiently evaluated.

As described above, the apparent change is apparently large, so it can be considered as a new crystal. However, since the spectral absorption spectrum does not change, it is considered that the aggregated structure that is the basis of electrophotographic performance is not broken. Even if a photoconductor is actually manufactured and evaluated, there is almost no change (see Examples). Further, the position (angle) does not change even if the intensity of the part where the peak of X-ray diffraction can be distinguished is reduced, so that the crystal is the same in that sense.

From the above, it is a matter of controversy to determine whether or not the crystal type appearing in this dispersion is a new crystal. However, it can be used at least as a measure of the degree of variance.

In short, the present invention employs X-ray diffraction and spectral absorption spectrum as a measure of the degree of dispersion to obtain a dispersion in an optimum state under conditions suitable for production.

Although both are measures of dispersion, what they represent are subtly different, and the measures of dispersion including correlation with electrophotographic performance alone have advantages and disadvantages.

In the X-ray diffraction used in the present invention, a concentrated optical system is used. This is the method used to measure ordinary powder samples. The dispersion was dropped on a commonly used glass sample stage and dried, and the dry film thickness was measured at 10 μm or more. The peak intensity is obtained by drawing a low-intensity portion within a range of ± 1.5 degrees from the position of the peak to obtain a baseline, and defining the height from the base line to the peak apex as the peak intensity ( (See FIG. 3). The spectral absorption spectrum is obtained by applying the dispersion to a transparent substrate such as glass or PET base and adjusting the film thickness so that the maximum peak absorbance is in the range of 1.0 to 2.0.

The first published titanyl phthalocyanine crystal having a maximum peak at 27.2 degrees is a comparative example disclosed in JP-A-62-67094.
No. 56).

However, this has a peak at 7.6 degrees as having the second intensity in the X-ray diffraction spectrum.
Rather, there is a peak at 9.0 degrees, which is different from the present invention. Further, the electrophotographic performance was poor and the charging potential was low (Comparative Example 4). Looking at the production examples, this one is obtained by hydrolysis of chlorotitanyl phthalocyanine, and is made amorphous (accurate in the acid paste step (a step of dissolving in sulfuric acid and pouring into water)) shown in the production example of the present invention. This is fundamentally different from those obtained by crystal transformation from those having a low degree of crystallinity.

Among some of the Y-type crystals studied by the inventors, particularly excellent ones have a small peak appearing at 6 to 8 (± 0.2) degrees, which is smaller than the main peak of 27.2 degrees. In most cases, the height of the peak was as small as 1/10 or less or an error peak was considered. Although the reason for this is not well understood, the inventor thinks as follows.

The peak in the range of 6 to 8 degrees has an original small peak of Y type (around 7.5 degrees).
Giant peak of α-type crystal originally at 7.6 ° (JP-A-61-239248 and JP-A-61-217050),
Type C at 6.9 degrees (Japan Hardcopy
There is a possibility that the maximum peak of the 89 ′ paper collection 103 (classification of 1989) is mixed. Both crystals have lower sensitivity than the Y type. In particular, the type C has almost no sensitivity (Japanese Hardcopy 89 ', 1
03 (1989)). Therefore, those having a peak in this region may be close to crystal types such as α-type and C-type.

As described above, the Y-type titanyl phthalocyanine is obtained by transforming titanyl phthalocyanine having a composition into an amorphous form by an acid paste treatment and then transforming the amorphous form.

There are two methods for synthesizing the titanyl phthalocyanine having the composition.

The synthesis method using diiminoisoindoline as a raw material (JP-A-2-28265) is a synthesis method which can be synthesized under mild conditions and contains few impurities.
The peak appearing at 6 to 8 degrees is small in the type crystal. In the method using phthalonitrile and titanium tetrachloride as raw materials, which was often performed before the announcement of this method (the above-mentioned document of Japan Hardcopy 89 '), it was synthesized due to variations in reaction temperature and delicate conditions of acid paste treatment. Y
The size of the peak at 6 to 8 degrees of the type crystal varies. Of course,
The performance of the finished product also varies greatly.

In the crystal conversion treatment, aromatic solvents such as o-dichlorobenzene, anisole and acetophenone, and halogens such as dichloroethane are used in the presence of water (may be a very small amount of water contained in the wet paste after the acid paste treatment). A wide range can be selected, such as etherified hydrocarbons, ethers such as THF, and ketone solvents such as cyclopentanone.

In the present invention, the method for dispersing the pigment is not particularly limited, but a sand grinder, a ball mill, an ultrasonic wave or the like can be used. Dispersion solvents are alcohols, T
A wide range of ethers such as HF, ketones such as methyl ethyl ketone, halogenated hydrocarbons such as dichloromethane, and esters such as ethyl acetate can be selected. Also, a small amount of water can be added to these solvents in order to prevent crystal transformation.

Among these solvents, esters having a branched structure, such as t-butyl acetate, are particularly preferred from the viewpoint of suppressing crystal transformation.

At the time of dispersion, a binder can be used.
Various resins such as a silicone resin, a butyral resin, and a polycarbonate resin can be used as the binder. The binder / pigment ratio usually ranges from 0 to 10, preferably from 0.1 to 4.0.

As described above, the dispersion of the present invention is derived from the properties of a Y-type crystal having high photoelectric conversion efficiency, and can be used in various applications such as sensors and solar cells. Among them, it is particularly suitable for the field of electrophotography such as digital copying machines and laser printers.

The dispersion of the present invention may contain various additives depending on the intended use, for example, antioxidants such as hindered phenols and hindered amines, hole transporting substances such as triphenylamines, electron transporting substances such as quinones, Etc. can be mixed.

Various known techniques can be used in combination with the electrophotographic photoreceptor using the dispersion of the present invention. Many dispersions satisfying the requirements of the present invention have a low binder concentration as can be seen from the examples, but after the preparation, a binder having a sufficient concentration for producing a single-layer photoreceptor in combination with another high concentration binder solution is prepared. It can be a liquid.

When used in the charge generation layer of the laminated photoreceptor, the dispersion can be used as it is or mixed with other liquids as in the case of a single layer.

Alternatively, a dispersion of another pigment, for example, a dispersion of an azo pigment, a phthalocyanine pigment, an anthraquinone pigment, an imidazole perylene pigment, an anthranthrone pigment, or the like can be used as a mixture.

A charge transport material (CTM) is also used in the electrophotographic photoreceptor to which the present invention is applied. However, there is no particular limitation, and known triphenylamine compounds, butadiene compounds, styryl compounds, hydrazone compounds and the like can be used. Can be used.

Since these charge transporting substances are usually provided in a layered form, a binder is used. Examples of the binder include polycarbonate resin, polystyrene resin, silicone resin, polyester resin and polyamide resin.

The photoreceptor of the present invention may be provided with an intermediate layer (undercoat layer) between the conductive support and the photosensitive layer for the purpose of adhesiveness and preventing charge injection from the conductive support.

As a material for the intermediate layer, a known polymer used for an adhesive or the like can be used. For example, in addition to known polymers used for adhesives such as polyamide resins, polybutyral resins, and polyvinyl acetate resins, partial hydrolysis products of metal alkoxides (for example, zirconium alkoxides, titanium alkoxides and the like) known as ceramic undercoats Condensates and the like can be mentioned.

The photoreceptor of the present invention may have a protective layer.

Next, before shifting to the description of the embodiments, examples of patents close to the present invention will be described to explain differences from the present invention.

Japanese Patent Application Laid-Open No. 2-256059 is a patent for the first time discussing the relationship between a peripheral crystal of a Y-type crystal and a spectral absorption spectrum. The dispersion method used in the patent is aimed at maintaining the crystal form. Examples 2 and 4 using a crystal within the concept of the present invention by a mild dispersion method with a large binder ratio (Note: Examples 2 and 4 of JP-A-2-256059)
Indicate that the peak wavelength of the spectral absorption is 817 nm and 83, respectively.
It is 0 nm. In addition, the peak around 7 degrees in X-ray diffraction is large, and Example 3 using a crystal outside the present invention has low sensitivity.

JP-A-3-71144 is a patent which refers to the type of solvent and the type of binder, and also aims at maintaining the crystal form (including long-term order). In all of the examples (note: the examples of JP-A-3-71144), the peak at 9.5 degrees is larger than 24.1 degrees, which is different from the present invention. In some of the comparative examples, the peak at 9.5 degrees is larger than that at 24.1 degrees, but there is a secondary peak at 680 nm in spectral absorption.

As described above, these are different from the present invention.

[0061]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the description, “parts” means “parts by weight”.

Production Example 102.5 g (0.8 mol) of phthalonitrile was suspended in 880 ml of methanol, a small amount (0.77 g) of sodium methylate was added as a catalyst, and ammonia gas was blown into the mixture to reflux for 4 hours. Then, the solvent is distilled off under reduced pressure, and after concentration, ethyl acetate is added, and the precipitated crystals are filtered to obtain 1,3-diiminoisoindoline (yield 6).
7 g, 58% yield).

203 g of the obtained diiminoisoindoline
Is suspended in 2.5 liters of orthodichlorobenzene, 143 g of titanium tetra-n-butoxide is added, and the mixture is heated at 150 ° C. to 160 ° C. for 6 hours under a nitrogen stream. After the reaction,
The mixture is filtered and washed with ortho-dichlorobenzene, 1% hydrochloric acid, water and then methanol to obtain crude titanyl phthalocyanine (yield 184 g, 91%).

Then, 20 g of the obtained crude titanyl phthalocyanine was dissolved in 200 ml of sulfuric acid under ice-cooling, and poured into 2.0 liters of water. Α type with low degree of conversion)
Obtain a wet paste of titanyl phthalocyanine.

On the other hand, a mixed solution of 200 ml of ortho-dichlorobenzene and 200 ml of water (separated into two layers) is prepared in a flask, and the above-mentioned wet paste of amorphous titanyl phthalocyanine is added thereto. Heat to 60 ° C. and stir for 6 hours for crystal transformation. Subsequently, the crystals poured into a large amount of methanol were filtered and sufficiently washed with methanol to obtain Y-type titanyl phthalocyanine (FIG. 4). 27.
It has a maximum peak at 2 degrees, and the peak around 9.5 degrees is split, but the height is larger than the peak height of 24.2 degrees. 9.5 degrees and 9.7 depending on the precision of the machine
Degrees can overlap. Further, the peak at 7.5 degrees is hardly noticeable.

Comparative Production Example 65 g of phthalonitrile and 400 m of α-chloronaphthalene
After 14.7 ml of titanium tetrachloride was added dropwise to the mixture (1) under a nitrogen stream, the mixture was heated and reacted at 210 to 230 ° C. for 3 hours.

After cooling, the crystals are filtered, washed with α-chloronaphthalene, then with methanol, washed with water at 80 ° C. and hydrolyzed. FIG. 5 shows the obtained crystals of titanyl phthalocyanine. Compared to FIG. 4 measured under the same conditions, the count number of diffracted X-rays is low, indicating that the crystallinity is low.

As shown in FIG. 4, the relative peak has a maximum peak at 27.2 degrees, but the peak at 9.5 degrees is rather higher at the shoulder at 9.0 degrees; The peak at 5 degrees is maximum at a low angle portion of 10 degrees or less, which indicates that the crystal is another crystal.

Then, in the same manner as in the Production Example, 20 g of this titanyl phthalocyanine was dissolved in 200 ml of sulfuric acid under ice-cooling.
The precipitate formed by pouring into 2.0 liters of water is filtered and thoroughly washed with water to obtain a wet paste of amorphous (more precisely, α-form having low crystallinity) titanyl phthalocyanine.

On the other hand, a mixed solution of 200 ml of orthodichlorobenzene and 200 ml of water (separated into two layers) is prepared in a flask, and the above-mentioned wet paste of amorphous titanyl phthalocyanine is added thereto. Heat to 60 ° C. and stir for 6 hours for crystal transformation. Then, the crystals generated by pouring into a large amount of methanol were filtered and sufficiently washed with methanol to obtain Y-type titanyl phthalocyanine (FIG. 6). This X
The line diffraction spectrum is almost the same as FIG.
The peak at 9 to 7.6 degrees is slightly larger than that in FIG.

Examples 1 to 5 and Comparative Example 1 820 ml of 4-methoxy-4-methyl-2-pentanone
And 1000 ml of t-butyl acetate, and 660 g of a t-butyl acetate solution (resin) of a silicone-modified butyral resin (polyvinyl butyral resin and organopolysiloxane obtained by dehydration condensation. JP-A-3-230166 Synthesis Example 5) 65 g), 130 g of the above-mentioned Y-type titanyl phthalocyanine was added, and 4.5 kg of glass beads (Hybee 24, diameter: 0.5 to 0.9 mm) was added and dispersed by a sand grinder. The size of the sand grinder is 5 liters, the number of rotating disks is 4, the size is 120 mm in diameter, and the number of rotations is 750 rpm.

The jacket was cooled by circulating cold water of about 10 ° C., dispersed for a specified time, and then t-butyl acetate 450 was dispersed.
It was diluted with 0 ml to obtain a dispersion.

These are designated as Samples 1 to 5 of the present invention and Comparative Sample 1. These X-ray diffraction spectra and spectral absorption spectra are shown in FIGS. 7 to 12, respectively.

Comparative Example 2 In a 200 ml stainless steel, 40 ml of t-butyl acetate, 125 g of glass beads, 0.67 g of Y-type titanyl phthalocyanine, and a silicone resin (“KR-5240, 15
% Xylene butanol solution (Shin-Etsu Chemical) 9 g (binder / pigment = 2/1 weight ratio) was added, and the mixture was dispersed at 1200 rpm for 4 hours using four 35 mm diameter disks.
This is referred to as Comparative Sample 2, and the X-ray diffraction spectrum and the spectral absorption spectrum are shown in FIG.

This is because the inventors have presented at a previous conference (Jap
an Hardcopy 89 ', 103 (19
89)) and previous patent application inventions (Japanese Unexamined Patent Publication No.
No. 9).

The rotational peripheral speeds of the disks were compared (120 × 7
50 and 35 × 1200), it is clear that Comparative Example 2 has milder conditions than the examples. Instead, the ratio of binder is high. Briefly, it can be said that the embodiment of the present invention attempted dispersion with a strong mechanical factor instead of dispersion with a strong physicochemical factor.

COMPARATIVE EXAMPLE 3 Except that the amount of binder was reduced to 1/4 in Comparative Example 2 (that is, the weight ratio of binder / pigment was the same as that of Example),
A dispersion was prepared under the same conditions as in Comparative Example 2. This is referred to as Comparative Sample 3, and the X-ray diffraction spectrum and the spectral absorption spectrum are shown in FIG.

Comparative Example 4 The crystal titanyl phthalocyanine shown in FIG. 3 was dispersed in the same manner as in Comparative Example 2. This is referred to as Comparative Sample 4, and the X-ray diffraction spectrum and the spectral absorption spectrum are shown in FIG.

Comparative Example 5 The crystal titanyl phthalocyanine shown in FIG. 4 was dispersed in the same manner as in Comparative Example 2. This is referred to as Comparative Sample 5, and the X-ray diffraction spectrum and the spectral absorption spectrum are shown in FIG.

Comparative Example 6 Dispersion was carried out for 22 hours in the same manner as in Example 4 except that warm water at 40 ° C. was circulated instead of cold water in the jacket. This is referred to as Comparative Sample 6, and the X-ray diffraction spectrum and the spectral absorption spectrum are shown in FIG.

Intensity ratio (7.5 / 9.5) of a peak appearing at 6.9 to 7.6 degrees and a peak appearing around 9.5 degrees in X-ray diffraction before dispersion. The intensity ratio between the peak appearing around 9.5 degrees after dispersion and the peak appearing around 24.1 degrees (9.
5 / 24.1). And the peaks of the spectral absorption spectrum are shown in Table 1 below.

[0082]

[Table 1]

Preparation of Electrophotographic Photoreceptor 3 parts of the copolymerized polyamide “CM8000” (Toray) were dissolved in 100 parts of methanol by heating and dip-coated on an aluminum drum to form a 0.4 μm-thick undercoat layer (UCL). Formed.

Next, the dispersion liquids of Examples 1 to 5 and Comparative Examples 1 to 6 were applied on the above-mentioned UCL, and CG having a thickness of 0.2 μm was applied.
L was formed. Next, 1.3 parts of a polycarbonate resin "Iupilon Z200" (Mitsubishi Gas Chemical), a part of the following compound (CTM-1), a small amount of silicone oil "KF"
Sample No. 54 (Shin-Etsu Chemical Co., Ltd.) in 10 parts of dichloroethane was applied by dip coating and dried to obtain 25 μm-thick photoreceptor samples 1 to 5 and comparative photoreceptor samples 1 to 6.

[0085]

Embedded image

Evaluation The above-described sample was mounted on a laser printer KL-2010 (Konica) (semiconductor laser light source), and continuous printing was performed 100,000 times.

In the photosensitive member sample 3, the unexposed portion potential V
The grid voltage is adjusted so that h becomes -700 V, and 1
The potential Vl of the exposed part at the time of irradiation of 750 μW was measured, and Vh and Vl after printing were measured. In addition, reversal development was performed at a development bias of -550 V, and black spots on a white background portion of the copied image were evaluated.

The black spots were evaluated by measuring the particle size and the number of the black spots using an image analyzer “Omnicon 3000” (Shimadzu Corporation).
The scale was based on the number of pieces per 0 cm ² .

[0089]

[0090]

[Table 2]

The photoreceptor samples 1 to 5 of the present invention have high sensitivity, the potential Vl does not increase so much by repetition, and there is no image defect.

In particular, the peak intensity at 9.5 degrees after dispersion is 2
4. Samples 2 to 5 that are 60% or less of 1 degree
Shows excellent electrophotographic properties. On the other hand, the comparative sample 1 in which the peak at 9.5 degrees hardly changes has a noticeable dispersion failure and has image defects.

In the sample having a large binder weight ratio (comparative photoreceptor 2), no image defect was found, but the potential rise was large. The same applies to Comparative Sample 5 in which the pigment is changed to that showing the X-ray diffraction spectrum of FIG.

In the comparative photoreceptor 3 in which the binder ratio was lowered, the rise in potential was suppressed, but image defects were observed. Further, the pigment of FIG. 3 (additional test of comparative example in JP-A-62-67094)
The comparative photoreceptor 4 in which is dispersed has poor chargeability.

Further, when examining the example in detail, the X-ray diffraction spectrum of Comparative Sample 5 dispersed for 33 hours was 27.
The 26.2 degree peak is slightly visible beside the 2 degree peak. This indicates that a part of the A-type crystal has been formed.
The peak at 0 nm has not yet appeared (the shoulder portion of the peak is 700 nm), and the performance also maintains high sensitivity.

Comparative sample 6 dispersed at an elevated temperature
Molding progressed, and the spectral absorption spectrum was 680 nm.
, A peak appears and the sensitivity is lowered.

[0097]

According to the present invention, a titanyl phthalocyanine which has a low residual potential when an electrophotographic photosensitive member is produced, has good repeated use characteristics, and has high sensitivity and high chargeability without image defects can be provided. A pigment dispersion,
An electrophotographic photosensitive member can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating generation of holes and photoelectrons when light is applied to a dye.

FIG. 2 is a diagram illustrating a peak in the present invention.

FIG. 3 is a view for explaining peak intensity in the present invention.

FIG. 4 is an X-ray diffraction diagram of titanyl phthalocyanine after production and before dispersion treatment.

FIG. 5 is an X-ray diffraction diagram of titanyl phthalocyanine after production and before dispersion treatment.

FIG. 6 is an X-ray diffraction diagram of titanyl phthalocyanine after production and before dispersion treatment.

FIG. 7 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 8 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 9 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 10 is a diagram showing an X-ray diffraction and a spectral absorption spectrum according to the present invention.

FIG. 11 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 12 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 13 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 14 is an X-ray diffraction and spectral absorption spectrum chart according to the present invention.

FIG. 15 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 16 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

FIG. 17 is an X-ray diffraction and spectral absorption spectrum diagram according to the present invention.

Claims (7)

[Claims] An X-ray diffraction spectrum of a dispersion of a titanyl phthalocyanine pigment has a Bragg angle (2).
θ) having a maximum peak at 27.2 ± 0.2 degrees and 2
4.1 has a second intensity peak at ± 0.2 degrees, the main peak of the spectral absorption spectrum is at 790 ± 20 nm,
A dispersion liquid of a titanyl phthalocyanine pigment, wherein a subpeak is not observed at 690 nm to 650 nm. 2. An X-ray diffraction spectrum having a Bragg angle (2
θ) is 9.5 ± 0.4 degrees, and the peak intensity is 2
It is less than 60% of the peak intensity of 4.1 ± 0.2 degrees,
2. The dispersion of a titanyl phthalocyanine pigment according to claim 1, wherein the dispersion does not have a clear peak at 8 degrees. 3. The dispersion of a titanyl phthalocyanine pigment according to claim 1, wherein the titanyl phthalocyanine pigment is obtained via an acid paste treatment. 4. The X-ray diffraction measurement of the titanyl phthalocyanine pigment before dispersion leads to a Bragg angle (2θ) of 27.2 ± 0.2.
At 9.5 ± 0.4 degrees, 2
4. The dispersion of a titanyl phthalocyanine pigment according to claim 1, wherein the dispersion has a clear peak at 4.1 ± 0.2 degrees. 5. The crystal before dispersion of the titanyl phthalocyanine pigment has a Bragg angle (2θ) of 27.1 ± by X-ray diffraction measurement.
It has a maximum peak at 0.2 degrees and 9.5 ± 0.4
The crystal form has a clear peak at 24.1 ± 0.2 degrees, and a peak that appears from 6.9 to 7.6 degrees has a peak intensity of 1/10 or less of the maximum peak. A dispersion of the titanyl phthalocyanine pigment according to any one of claims 1 to 4. 6. The dispersion of a titanyl phthalocyanine pigment according to claim 1, wherein the titanyl phthalocyanine pigment is synthesized via diiminoisoindoline. 7. An electrophotographic photoreceptor produced using a dispersion of the titanyl phthalocyanine pigment according to claim 1. Description: