JPS6392956A - Photosensitive body - Google Patents

Abstract

PURPOSE:To prevent the deterioration in an electrophotographic characteristic by photoirradiation by incorporating an orange dye into the layer on the incident light side of a photosensitive body laminated with an electric charge generating layer and charge transfer layer. CONSTITUTION:The charge generating layer 2 and the charge transfer layer 1 laminated on a conductive substrate 3 and the orange dye is added to the layer 1 on the incident light side with respect to the boundary 4 of the layers 2, 1. The orange dye is usable by selecting the same from disperse orange, solvent orange, etc. The orange dye is added into the layer 1 or the layer 5 in the case of providing a protective layer 5 on the layer 1. Then, light of harmful wavelengths (e.g: 450-500nm) is absorbed in the orange dye before arriving at the boundary face 4 and, therefore, the deterioration of the photosensitive body by the photoirradiation is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a photoreceptor whose electrophotographic characteristics are prevented from deteriorating due to light irradiation.

Prior art If an electrophotographic photoreceptor is left in a bright place, the characteristics of the photoreceptor deteriorate, resulting in problems such as a decrease in charging ability or an increase in residual potential. Characteristic deterioration in bright places may occur due to the installation of the photoreceptor in the copying machine or the maintenance of the copying machine.
This is particularly likely to occur if the photoreceptor is left exposed to light. Photoreceptors that are subject to severe deterioration may also be deteriorated by erase light that is repeatedly irradiated within a copying machine.

When a functionally separated photoreceptor is irradiated with light using a continuous interference filter, the characteristics of the photoreceptor deteriorate due to the absorption edge wavelength of the charge transport layer.
Wavelength range of absorption edge wavelength plus 50 nm (mainly 450 nm ~
600 nm), which indicates that the light is in a wavelength range where the light absorption coefficient of the charge transport layer is small, and that the light that has penetrated into the charge transport layer and reached the charge generation layer,
It has become clear that one of the causes is that it occurs at the charge transport layer/charge generation layer interface.

Regarding photodeterioration, since ultraviolet light of 450 nm or less is harmful, a method of adding an ultraviolet absorber or a dye having absorption at 450 nm or less has been proposed (for example, Japanese Patent Laid-Open No. 120260/1983) , JP-A-58-1
No. 63945, Japanese Patent Application Laid-Open No. 163946/1983,
JP-A-58-163947, JP-A-58-163
948, etc.).

However, in order to sufficiently eliminate photodeterioration, it is necessary to increase the amount of additives added, and in this case, the carrier movement within the charge transport layer is inhibited by the additive, resulting in a decrease in the mobility of the charge transport layer. An adverse effect has occurred.

Problems to be Solved by the Invention Therefore, the inventor conducted repeated research on photodegradation, and found that
When a functionally separated photoreceptor is irradiated with light using a continuous interference filter, the characteristics of the photoreceptor deteriorate due to the absorption edge wavelength of the charge transport layer.
Wavelength range of absorption edge wavelength plus 50 nm (approximately 450 nm ~
500 nm), it was found that light in a wavelength range where the light absorption coefficient of the charge transport layer is small acts as harmful light.

Furthermore, light in a harmful wavelength range may penetrate into the charge transport layer and generate trap levels, or may reach the charge generation layer.
It has also become clear that the injection barrier height at the charge transport layer/charge generation layer interface is reduced.

As mentioned above, in a stacked photoreceptor with a charge transport layer/charge generation layer, its deterioration is caused by light penetrating inside the charge transport layer, causing a decrease in characteristics such as photosensitivity. Absorbents and the like cannot overcome this drawback.

SUMMARY OF THE INVENTION An object of the present invention is to solve such problems and to provide a photoreceptor that prevents deterioration of characteristics of the photoreceptor caused by light irradiation.

A two-step method for solving the problems The present invention provides a laminated type photoreceptor having a charge generation layer and a charge transport layer on a conductive substrate, in which an orange dye is applied to the interface between the charge transport layer and the charge generation layer by incident light. It relates to a photoreceptor characterized in that the photoreceptor is contained in a side layer.

Examples of the structure of a self-contained photoreceptor having a charge generation layer and a charge transport layer on a conductive substrate are shown in FIGS. 1 to 4.

Figure 1 shows a photoreceptor in which a charge generation layer (2) and a charge transport layer (1) are laminated on a conductive substrate (3). It is contained in the charge transporter (1) which is on the incident light side with respect to the interface (4) of (1).

In FIG. 2, the stacking order of the charge generation layer (2) and the charge transport layer (1) is reversed to that in FIG. 2), and the orange dye is contained in the charge generation layer (2) which is on the incident light side with respect to the interface (4) between the charge generation layer (2) and the charge transport layer (1).

Figure 3 shows a photoreceptor with a protective layer (5) provided on the charge transport layer (1) in the configuration of the photoreceptor shown in Figure 1, and the orange dye is applied to the interface (4). surface on the incident light side,
That is, it is contained in the charge transport layer (1) or the protective layer (5).

Figure 4 shows a photoreceptor with a protective layer (5) provided on the charge generation layer (2) in the configuration of the photoreceptor shown in Figure 2, and the orange dye is applied to the interface (4). surface on the incident light side,
That is, it is contained in the charge generation layer (2) or the protective layer (5).

The present invention is not limited to photoreceptors having the above structure, but can also be applied to photoreceptors having an appropriate undercoat layer or the like.

An important point in the present invention is that in a laminated photoreceptor having a charge generation layer and a charge transport layer on a conductive substrate as described above, the orange dye is on the side of the incident light side with respect to the interface between the charge transport layer and the charge generation layer. It is contained in the layer of With such a configuration, harmful wavelengths (450
~500 nm) is absorbed by the orange dye before reaching its interface. Since the harmful wavelength range of orange dye matches the absorption peak position of the dye, harmful light can be efficiently blocked with a small amount added.

In the configuration examples of the photoconductor shown in FIGS. 1 to 4, the present invention is a photoconductor based on the configuration shown in FIG. This is effective for photoconductors configured on the incident light side.

As the orange pigment, one selected from the group belonging to the orange color index such as disperse orange and solvent orange can be used. At this time, the orange dye is selected in consideration of the light absorption properties of the charge transport agent, charge generation agent, etc. described below.

Hereinafter, for convenience, a charge generation layer (
2) A photoreceptor (FIG. 1) based on a structure in which charge transport layers (1) are sequentially laminated will be described.

The basic composition of a photoreceptor consisting of such a charge transport layer and a charge generation layer is AQSAQ alloy, Ni, Cu,
A charge generation layer is formed on a conductive substrate such as gold, platinum, Mylar on which they are deposited, or conductive plastic.

Methods for forming the charge generation layer include a vacuum evaporation method and a method of coating a dispersion of a charge generation material and a binder resin. The thickness of this charge generation layer needs to be thick enough to absorb incident light, but if it is too thick, carrier movement within the charge generation layer will become the rate limiting factor for sensitivity, so it is best to keep it below 1μX. preferable.

As the charge generating material, selenium, selenium alloy, a-8i,
Azo pigments, disazo pigments, trisazo pigments, pyrylium dyes, quinone pigments, indigo pigments, quinacridone pigments, phthalocyanine pigments, threne pigments, perylene pigments, dioxazine, etc. can be used.

As the binder resin for the charge generation layer, polyester, polyvinyl butyral, (meth)acrylic resin, polyvinyl chloride, polyvinylidene chloride, alkyd resin, phenol resin, phenoxy resin, etc. can be used.

A charge transport layer containing an orange dye is formed on this charge generation layer. Formation methods include a method of direct polymerization on the charge generation layer, such as plasma polymerization, and a method of dissolving the binder resin and charge transport material in a solvent and applying the solution. However, the formation of the charge transport layer by plasma polymerization in the former case is
This is used when it is not necessary to contain an orange dye, and the latter solution coating method is used when an orange dye is to be contained. The thickness of the charge transport layer is limited by carrier mobility and printing durability, and is generally 5 μR to 3 μR.
Set to a range of 0 μ shoulder.

The amount of orange dye added is 0°1-10 relative to the binder resin.
% by weight, preferably 1-5% by weight.

If it is less than 0.1% by weight, the effect of the present invention due to the addition of orange dye cannot be obtained, and if it is more than 10% by weight, it will cause a decrease in the photosensitivity of the photoreceptor and a decrease in the mobility of the carrier, which is not preferable. . The specific addition amount may be selected in consideration of the film thickness and the like so that 99% of the wavelength components of incident harmful light are absorbed.

Charge transport agents that can be used in the present invention include fluorenone derivatives such as trinitrofluorenone and tetranitrofluorenone, xanthone derivatives, anthraquinone derivatives,
Chloranil, bromoanil, tetraanoethylene,
Electron-transporting substances such as tetracyanobenzene, trinitrobenzene, pyromellitic anhydride, 3,5-dinitrobenzoic acid, and tetraanoquinodimethane, and polymerized polymers of these substances, as well as anthracene, pyrene, carbazole derivatives, and tetrazole. Hole-transporting substances such as derivatives, ferrocene derivatives, phenodeazine derivatives, pyrazoline compounds, hydrazone compounds, styryl compounds, styrylhydrazone compounds, thiazole compounds, oxazole compounds, oxadiazole compounds, imidazole compounds, phenylenediamine derivatives, and dirubene derivatives; A polymerized product can be used. Particularly effective in the present invention are hydrazone compounds, pyrazoline compounds, and styryl hydrazone compounds whose absorption edge extends to visible light.

As the binder resin for the charge transport layer, (meth)acrylic, acrylonitrile, styrene, bukunoene, vinyl acetate,
Resins such as vinyl chloride and copolymers thereof, polycarbonates, polyarylates, polyesters, polysulfones, polyethersulfones, polyamides, epoxy silicones, urethanes, and the like can be used, but are not limited to these.

A protective layer (5) (FIG. 3) may be further provided on the photoreceptor (FIG. 1) having the basic structure described above. In this case, the orange dye may be present in the charge transport layer (1), the protective layer (5), or both layers. In both layers? ? If you want to
The orange dye in each layer is used in such a manner that the total amount of the orange dye added becomes the above-mentioned amount.

The protective layer is selected from a group of binder resins that can be used to construct the charge transport layer or the charge generation layer, and is prepared by coating and drying a solution of an orange dye or other additives dissolved or dispersed in a suitable solvent. , with a thickness of 0.1 to 10 μm, preferably 1 to 5 μm.

The present invention further provides a photoreceptor having an inverse configuration to the photoreceptor having the basic configuration described above (FIG. 1), that is, as shown in FIG. 2, a charge transport layer is provided on a conductive substrate (3). (1
) and a charge generation layer (2) are sequentially laminated. In this case, because the charge generation layer (2) is thin, a protective layer (5) is added on top of the charge generation layer (2).
It is preferable to provide

In a photoreceptor (FIG. 2 or FIG. 4) in which a charge transport layer and a charge generation layer are sequentially laminated on a conductive substrate, an orange dye is contained in the protective layer, the charge generation layer, or both layers. In this case, the amount of orange dye added is 1 to 50% by weight, preferably 5 to 20% by weight, based on the binder resin. If it is less than 1% by weight, the effects of the present invention cannot be obtained, and if it is more than 50% by weight, the photosensitivity of the photoreceptor and the mobility of carriers will be lowered, which is not preferable.

The present invention can also be applied to a single-layer type photoreceptor that does not have a charge generation function and a charge transport function integrated. In this case, a protective layer is always provided as the uppermost layer, and an orange dye should not be contained in the protective layer.

The photoreceptor of the present invention may also have an intermediate layer and an adhesive layer as necessary, and may contain other additives in addition to the orange dye.
For example, a known ultraviolet absorber may be included.

Example 1-10 A mixed solution having the following composition was dispersed using a sand grinder for 13 hours.

Disazo pigment (CDB)... 19
Polyester (Toyobo V-200)... 19
Cyclohexanone...989 After drying this dispersion on an A12 sheet with a bar coater, the film thickness is 0.
It was applied to a thickness of 3 μm and dried to form a charge generation layer.

Next, 5 g of hydrazone compound (A) having the following structure, 5 g of polycarbonate (Ondai Kasei Nippon Co., Ltd. -1300), and 0.10 g of the orange dye shown in Table 1 were dissolved in THF'309, and this solution was applied onto the charge generation layer. After drying, the coating was applied to a film thickness of 15 μl and dried to form a charge transport layer.

The photoreceptor containing the orange dye in the charge transport layer obtained as described above was attached to a photoreceptor tester (FIG. 5) having a configuration similar to that of a copying machine, and the electrophotographic characteristics were measured.

That is, the photoreceptor obtained according to the present invention was attached to a photoreceptor drum (6), and after being charged to about 500 V with a charger (7), the initial surface potential (vO) of the photoreceptor after 0.3 seconds, and the after charging. The surface potential (V i ) after being exposed to white light (8) from a halogen lamp and the residual potential (Vr) after being neutralized by a light eraser (10) after exposure were measured using a probe (9).

As an evaluation method, after measuring the electrophotographic properties before light irradiation, the samples were left under a fluorescent lamp at 3000 lux for 10 minutes, and the electrophotographic properties were measured immediately after the irradiation and after repeating 100 times after the irradiation. Changes in chargeability after irradiation and repeated stability after irradiation were investigated. The results are shown in Table 2.

Example 11 Copper phthalocyanine was used instead of CDH as the charge generating material, no orange dye was contained in the charge transport layer,
A charge transport layer and a charge generation layer were formed in this order on Aρ with the same composition as in the above example.

Furthermore, after drying a solution with the following composition on top of this, the film thickness was 3 μm.
It was applied to the shoulders to provide a protective layer.

Composition Heavy! ri (9) Polyester 10 (Toyobo V-
200) Dioxane 90-year-old microwave dye Electrophotographic properties were measured in the same manner as in 1. The results are summarized in Table 2.

Table 2 Comparative Examples 1 to 6 Charge generation layers were formed in the same manner as in Examples (1 to 10),
Thereon, instead of the orange dye of the example, the additives shown in Table 3 below were added to form a charge transport layer.

Table 3 Table 4 shows the results of the same measurements as in Example (+-10) for these photoreceptors.

Comparative Example 7 A charge transport layer and a charge generation layer were formed on a Q sheet, and a protective layer similar to Example 11 except that the orange dye was removed thereover was formed thereon. Electrophotographic properties were similarly measured. The results are summarized in Table 4.

Table 4 [Evaluation] Comparing the results of the comparative example and the example, the blank sample of the comparative example shows an extremely large increase in Vr due to repeated light irradiation. Furthermore, in a system in which an ultraviolet absorber and a yellow dye are added, an addition amount of 2% by weight based on the binder resin hardly produces any effect.

In contrast, the orange dye is 2% by weight based on the binder resin.
In the system in which it was added, the increase in Vr during repetition was significantly improved.

The photodegradation test of 30001ux for 10 minutes is an extreme condition, and if the Vr rise in this test is improved to less than 00V per month, photodegradation will not be a problem at all in actual handling.

In Example 11, in the case of a configuration opposite to that of Example 1-1o, in the case of PPC, the light at the absorption edge of the charge transport layer is normally absorbed by the charge generation layer, but in the case of laser, etc. In some cases, the charge transport layer enters the charge transport layer without being absorbed by the charge generation layer. In such a case, characteristic deterioration due to light occurs, but by including an orange dye in the protective layer as in Example 11, photodeterioration can be suppressed.

Examples 12 to I6 Examples 1 to 10 were prepared using τ type metal phthalocyanine (manufactured by Toyo Ink Co., Ltd.) instead of CDB as the charge generating material.
) A charge generation layer was formed in the same manner as in (1).

Further, the amount of the orange dye of Example 5 added to the binder resin was Iwt, %, 2wt, %, 3wt, %, 4w.

%, 5wt, and % to form a charge transport layer.

These photoreceptors were subjected to the same measurements as in Examples (1 to 10). The results are shown in Table 5.

Comparative Examples 8-13 A charge generation layer of τ-type metal-free phthalocyanine was formed in the same manner as in Examples (12-16), and Comparative Examples 4.6
5wt of each of the yellow pigments used in the binder resin
, %, 10wt, %, 15wt, %, charge transport layers were formed.

These photoreceptors were subjected to the same measurements as in Examples (1 to 10). The results are shown in Table 6.

The effect of the amount added was investigated in Examples 12 to 16 and Comparative Examples 8 to 13.

1 to 5 wt, % for orange pigment, 5 for yellow pigment
Optical fatigue can be improved by adding ~15vt,%.

Orange dye can produce the same effect with about 1/3 of the amount added as yellow dye. This is because the absorption edge of CTL is around 450 nm (Fig. 6), and the absorption peak of orange dye is around 450 nm (Fig. 7), and it can cut harmful light more efficiently than yellow dye. This is for the purpose of

In the case of a yellow dye, since it is added in a large amount, it tends to have adverse effects, and as in Comparative Examples 11-13, the charging ability may decrease after light irradiation. Further, even if there is no problem in the initial characteristics and optical peak characteristics, problems may occur in the repeatability characteristics, temperature characteristics, etc. due to the decrease in mobility due to the addition of the dye, so it is desirable that the amount of m added is small.

Effects of the Invention According to the present invention, in a laminated photoreceptor having a charge generation layer and a charge transport layer on a conductive substrate, an orange dye is contained in a layer on the incident light side with respect to the interface between the charge transport layer and the charge generation layer. By doing so, the interface between the charge generation layer and the charge transport layer is not affected by harmful light, so that deterioration of the characteristics of the photoreceptor due to light irradiation can be suppressed.

[Brief explanation of the drawing]

1 to 4 are diagrams showing an example of the structure of a photoreceptor to which the present invention is applicable. FIG. 5 is a diagram showing a schematic configuration of a photoreceptor tester. FIG. 6 is a diagram showing the transmittance of the charge transport layer. FIG. 7 is a diagram showing the absorption spectrum of the dye. The symbols in the diagram are as follows. DESCRIPTION OF SYMBOLS 1... Charge transport layer, 2... Charge generation layer, 3...
... Conductive substrate, 4 - Interface, 5 - Protective layer,
6... Photosensitive drum, 7... Charging 23,
8-light, 9...probe, IO
...Optical eraser. Patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Tamotsu Maeda and two others Figure 5 Figure 6 5C) CJ 4 (J (J Wavelength (nm)
500 600 No. 71'21 N *tnm> Procedural Amendment Commissioner of the Patent Office November 1701, 1985,
Display of the case Patent Application No. 238294 of 1986, Relationship with the amended case Patent applicant Iosa Tonohiga 7ri Nona-2 Address Osaka Kokusai Building 4, 2-30 Azuchi-cho, Higashi-ku, Osaka
Agent address: 61 Mi 2-1, Higashi-ku, Osaka-shi, Osaka 540
No. 7, Contents of amendment ([) Specification, page 2, lines 4 to 12, [The deterioration of the characteristics of the photoreceptor has become clear. ] Delete the description. that's all

Claims (1)

[Claims] 1. In a laminated photoreceptor having a charge generation layer and a charge transport layer on a conductive substrate, an orange dye is contained in a layer on the incident light side with respect to the interface between the charge transport layer and the charge generation layer. Characteristic photoreceptor.