JPS5850542A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor causing slight dark attenuation and undergoing slight optical fatigue by adding a silane coupling agent to the charge generating layer or the charge transferring layer of an electrophotographic receptor having an electrically conductive layer, the charge generating layer and the charge transferring layer. CONSTITUTION:In an electrophotographic receptor having an electrically conductive layer, a charge generating layer contg. a charge generating org. pigment and a charge transferring layer having charge retaining and transferring functions, a silane coupling agent is added to the charge generating layer and/or the charge transferring layer. When the coupling agent is added to the charge generating layer, the amount is 0.5-40wt%. More than 40wt% coupling agent has a favorable effect of improving the initial potential, dark attenuation and optical fatigue, yet it reduces the sensitivity. When the coupling agent is added to the charge transferring layer, the amount is 0.05-30wt%.

Description

[Detailed description of the invention] The present invention has a charge generation layer and a charge transport layer.

The present invention relates to an electrophotographic photoreceptor that exhibits less fading and light fatigue.

Conventionally, in electrophotographic materials that use photoconductive substances as photosensitive materials, selenium and zinc oxide have been used.

Inorganic conductive substances such as titanium oxide and cadmium sulfide have been mainly used.

However, many of these are highly toxic.

There are also problems with the method of disposal.

On the other hand, photosensitive materials that use organic photoconductive compounds are generally less toxic than those that use inorganic photoconductive substances, and also have excellent properties such as transparency, flexibility, @sagi property, and surface smoothness. Recently, it has been widely studied due to its advantages.

Among these, composite photoreceptors that separate the functions of charge generation and transport have been developed in recent years because they can significantly improve sensitivity, which was a major drawback of conventional photoreceptors using organic photoconductive compounds. Rapid progress is being made.

However, when these composite photoreceptors are applied to, for example, an electrophotographic device using the Carlson method.

Repeated use lowers the initial potential and increases dark decay, often resulting in fogging in the resulting copied image and significant loss of image contrast. Furthermore, when using an electrophotographic device (KJ), which repeatedly performs development and transfer to obtain a large number of copied images without damaging the silent IK latent image formed by multiple exposures, the dark decay is large, resulting in a large number of copied images. gradually decreases.

Although the composite photoreceptor has a high degree of dreaminess, it also suffers from large dark decay when exposed for long periods of time.

It has the disadvantage that a photofatigue phenomenon occurs in which the darkening phenomenon increases as the initial potential decreases. In contrast, when the charge generation layer is thick, the characteristics deteriorate significantly due to optical fatigue.

The present invention solves these problems.

(11lii is small.

12) Even after repeated i-electron exposure, the charge potential decreases little, and dark decay does not increase (ie.

(less light fatigue).

(3) Another object is to provide a composite electrophotographic photoreceptor exhibiting high sensitivity.

That is, the present invention provides 414. In an electrophotographic photoreceptor having a charge-generating layer containing an organic pigment that generates a charge and a charge-transporting layer having functions of charge retention and transport, at least one of the charge-generating layer and the charge-transporting layer contains silane. The present invention relates to an electrophotographic photoreceptor containing a coupling agent.

The materials used in the electrophotographic photoreceptor of the present invention are described below.

First, examples of organic pigments that generate charges included in the VT charge generation layer include azoquinbenzene, disazo, trisazo, and benzimidazole pigments.

Pigments known to generate charges such as 11-quinone type, indigoid type, quinacridone type, phthalocyanine type, perylene type, and methine type can be used. These pigments are 9%, e.g.
7-37544 publication 1% Kaisho 47-18543 publication, I\i Kaisho 47-18544 publication, 411F Kaisho 4
8-43942, JP 48-70538, JP 49-1231, JP 49-1055
Publication No. 36 @ 1% Publication No. 1983-75214, Japanese Patent Publication No. 50-75214
It is disclosed in JP 0-92738 and the like. In addition to these, any organic pigment that generates a stain carrier upon irradiation with light can be used.

The charge transporting substances that are the main components of the charge transport layer include polymeric compounds such as poly-N-vinylcarbasol, chlorogenated poly-N-vinylcarbasol, polyvinylpyrene, polyvinylindoquinoxaline, and polyvinylbenzo Theophene, polyvinylanthracene, polyvinylacridine, polyvinylpyrazoly7, etc. are low molecular weight compounds such as fluorene and fluorenone.

λ7-sinitro 9-fluorenone, λ4,7-dolinitro 9-fluorenone, 4H-indeno (1,2 6
) Thio7en-4-one, 3.7-Nodinitrozi, benzothiophene-5-oxide, l
- Glombirene, 2-phenylpyrene.

Carbasol, 3-phenylcarbazole, 2-phenylindole, 2-niphenylna7talene, oxadiazole, trianol, l-phenyl-3-(4-diethylaminostyry/L, )T5-(4-diethylaminophenyl)pyrazoline, 2 -Phenyl-4-(4-diethylaminophenyl)-5-phenylozole, triphenylamine, imidazole, chrysene.

Examples include tetrafen, acridene, and their enzyme derivatives.

Before, '-charge generation layer 1! # Additives such as binders, plasticizers, fluidity imparters, pinhole inhibitors, etc. that are commonly used in electrophotographic photoreceptors can be used in the transport layer. Examples of the binder include silicone resin, polyamide, polyurethane, polyester, epoxy resin, polyketone, polycarbonate, polystyrene, polymethyl methacrylate, polyacrylamide, etc. In particular, the binder used in the charge transport layer is silicone. Resin, styrene resin, etc. are suitable. Furthermore, thermosetting resins and photocurable resins that are crosslinked by heat and/or light can also be used. In any case, there are no particular limitations as long as the resin is insulative and has a film-forming ability in a normal state, or a resin that can be cured by heat and/or light to form a film. Examples of the armoring agent include rogenated paraffin, dimethylnaphthalene, dibutyl phthalate, and the like.

Examples of the fluidity imparting agent include Modaflow (manufactured by Montento Chemical Co.) and Acronal 4F (Bus7 Co., Ltd.), and examples of the pinhole inhibitor include benzoin and dimethyl terephthalate.

These are used by selecting 4'Jt, and the play may be determined as appropriate.

In the present invention, '(72/coupling agent contained in at least one of the charge generation layer and the charge transport layer) is vinyltrichlorosilane.

Vinyltriethoxysilane, vinyltris(β-methoxyethoxy)sila/, vinylcylene such as r-methacryloxypropyltrimethoxysilane, epoxy 7lane such as γ-glycidoxypropyltrimethoxysilane, N-β
-(aminoether)-r-aminopropyltrimethoxysilane, r-aminopropyltriethoxysila/.

Aminones such as N-β-(aminoethyl)-r-aminopropylmethyldimethoxine, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, hydrochlorides thereof, Examples include mercaptocynes such as γ-mercaptoglobil trimethoxysilane. In particular, aminosilane is highly effective in improving dark decay and optical fatigue.

When the charge generation layer contains the above-mentioned silane coupling agent, the silane coupling agent is contained in the TVI generation layer in an amount of 0.5 to 40 times, preferably 1 to 20 times.

If it is less than 0.5 weight, there is no effect of reducing dark decay and photo fatigue, and if it exceeds 40 weight, the effect of improving the initial potential, dark decay test, and photo fatigue is good, but the sensitivity is poor. descend. In addition to the above-mentioned organic pigment and 7-rank coupling agent in the charge generation layer, the cyanine dye paste and/or compound represented by the following general formula (1), which has an effect of improving dark decay and light fatigue, is represented by the following general formula +II). It is also possible to add the styryl dye bases shown.

(However, in the general formula (11, R,, R,, R,, R4,
R and 几 are hydrogen atoms,...rogen atoms, alkyl groups.

It is an aralkyl group, a butyl group, a hydroxyfur group, a phenyl group or a substituted phenyl group, and R1 to R6 may be the same or different. ) (However, in the general formula (■), R7, , R9 and R1
゜ represents a hydrogen atom, a halogen atom, an alkyl group, an aralkyl group, an acyl crystal, a hydroxyl group, a phenyl group or a substituted phenyl group, and R1 to R4 may be the same or different. RII and R□ are hydrogen atoms or alkyl groups, and R1 and R1 may be the same or different. Examples of the cyanine dye paste represented by the general formula (1) include:

C,H.

Examples of the styryl dye base represented by the general formula (II) include:

etc.

When the above cyanine dye base and/or styryl dye base is used in combination with the above silane coupling agent, the cyanine dye base and/or the above silane coupling agent may be used together with the cyanine dye base and/or styryl dye base.
Alternatively, it is necessary to adjust the respective contents of K so that the styryl dye paste containing needles in the charge generation layer is 40% by weight or less. If it exceeds 40% by weight, the sensitivity of the electrophotographic photoreceptor decreases. Components in the charge generation layer other than the above-mentioned organic pigment, silane coupling agent, and optionally cyanine dye base and/or styryl dye base include:
Examples include the above-mentioned binders, lubricants, and additives. The binder is used in an amount of up to 300% by weight relative to the organic pigment.

When the weight exceeds 300 s, the electrophotographic properties deteriorate. It is preferred that the plasticizer is used in an amount of less than 5% by weight based on the organic pigment. Other additives may be used as appropriate in amounts of 11t3 times 11- or less.

When the charge transport layer contains the above-mentioned silane coupling agent, αo5 to 30 weight −1 preferably 0 in the charge transport layer.
．． It is contained in an amount of 1 to 101 t%. If it is less than 0.05 weight, the effect of reducing dark decay and light fatigue is lost.
If it exceeds 30 tLs, the initial potential, dark decay, and optical fatigue are improved, but the sensitivity decreases and the residual potential increases. In addition to the charge transporting substance and the silane coupling agent, the above cyanine dye base (1) and/or styryl dye base, which has an effect of improving darkening test and optical fatigue, can be added to the charge transport layer.

When the above cyanine dye base and/or styryl dye base is used together with the silane coupling agent, the silane coupling agent and the cyanine dye base and/or
Alternatively, it is necessary to adjust the respective contents so that the total amount of steryl dye paste in the charge transport layer is 30 weight tts or less. 30] If it exceeds 1, the electrophotographic properties will deteriorate. The above charge transporting substance in the charge transporting layer.

Components other than the silane coupling agent, cyanine dye base and/or styryl dye paste that may be used include the above-mentioned binder and 5T plasticizer.

There are additives, etc. When a polymer compound is used as the charge transporting substance, a binder may not be used, but a binder may be used in an amount of 300 weights or less relative to the polymer compound.

If it exceeds 300 weight J1-, the electrophotographic properties will deteriorate. In addition, when a low molecular compound is used as the charge transport substance, the binder has a molecular weight of 30 to 300% relative to the low molecular compound.
It is heavily used. If the thickness is less than 30 layers, it will be difficult to form a charge transport layer.

If it exceeds 300 μm kts, the electrophotographic properties will deteriorate. The above-mentioned plasticizer and additive are suitably used in an amount of not more than 1 to 5 parts of the above-mentioned '-charge transporting substance.

The silane coupling agent is contained in at least one of the charge generation layer and the charge transport layer, but is preferably contained in both the charge generation layer and the charge transport layer.
The improvement effect on visual fatigue and photofatigue is greater.

In the present invention, the conductive layer refers to paper or plastic film treated for conductivity, or a plastic film laminated with metal foil such as aluminum.

It is a conductor such as a metal plate.

The electrophotographic photoreceptor of the present invention preferably has a charge generation layer formed on the conductive layer 1- and a charge transport layer formed thereon in terms of electrophotographic properties. You can leave it there. Charge generation (- thickness is 0.1 to 10
μm, preferably 0.2 to 5 μm, 0.1
Below μm.

It becomes difficult to form a charge generation layer uniformly.

When the thickness exceeds 10 μm, electrophotographic properties deteriorate.

Further, the thickness of the charge transport layer is 5 to 50 μm, preferably 8 μm.
~20 μm. If it is less than 5 μm, the initial potential decreases,
If it exceeds 50 μm, sensitivity decreases.

To form a charge generation layer and a charge transport layer.

The components of each layer are uniformly dissolved or dispersed in a ketone solvent such as acetate/methyl ethyl ketone, an ether solvent such as tetrahydrofuran, or an aromatic solvent such as toluene or xylene, and then coated on the conductive layer and dried. This can be done by

The electrophotographic photoreceptor of the present invention may further have a thin adhesive layer or barrier layer immediately above the conductive layer. Also 9
A protective layer such as silicon can be provided on the surface. □ The copying method using the electrophotographic photoreceptor according to the present invention involves charging and exposing one surface to light as in the conventional method.

All you have to do is develop it, transfer the image onto plain paper, and fix it.

The electrophotographic photoreceptor of the present invention has excellent advantages such as high sensitivity, low dark decay, and little optical fatigue.

Comparative examples and examples are shown below.

Each material used in the examples below is listed below. The numbers in parentheses indicate abbreviations.

(1) Organic pigment/disazo type that generates charge: 8ymular Fast Blue
4135 (SFB) [Dainippon Ink Chemical Industry ■Product name] Q7 RiCI cyanine type: Fastogen Blue
FGF (FGF) [Dainippon Ink & Chemicals ■Product name] o-1-noazo series: Re5jno Red BX
(BX) Cyto Nishi Rokusha ﾾ Kogyo ■Product name] (2) Charge transport substance・2-(p-shu1-ruamino)phenyl-4-(p
-dimethylamino)7-c-el-6-(0-chloro)phenyl-1,3-oxazole
(OXZ)-1-phenyl-3-(p-diethylaminostyryl)-5=(p-diethylaminophenyl)
Pyrazoline (pyz) (3) Silane coupling agent in the present invention as O aminosilane and N-β-
(Aminoethyl)-r-aminoglobiltrimethoxysilane: (KBM 603. Shin-Etsu Chemical ■Product name) r-Mercaptopropyltrimethoxysilane as G-mercaptosilane: (KBM 803゜Shin-Etsu Chemical ■
Product name] (4) Binder O Boristile/: Hammer ST [Mitsui Toatsu Chemical ■Product name] O silicone varnish: KP-255 (non-volatile content 50-)
[Shin-Etsu Chemical ■Product name] 0 Polyester: Vylon 200 [Toyobo ■Product name] (5) Dye paste O cyanine dye paste (NK-2321, Japan Photosensitive Dye Research Institute product name) O styryl dye paste (NK-2020 , Japan Photosensitive Color Research Institute (trade name)] Comparative Examples 1 to 3 The organic jjAII+ and binder shown in Table 1 were blended in a predetermined amount.

Methyl ethyl keto/ was added to this so that the solid content was 3 weight, and 80 t of this crystal mixture was kneaded for 8 hours using a ball mill (3-inch pot mill manufactured by Nippon Kagaku Togyo). The obtained pigment dispersion is applied to an aluminum plate (
conductive layer).

It was dried at 90° C. for 15 minutes to form a charge generation layer with a thickness of 1 μm.

Next, predetermined amounts of the charge transporting substance and binder shown in Table 1 were blended, and methyl ethyl ketone was added thereto so that the solid content was more than 30% by weight, and completely dissolved. This solution was applied onto the charge generation layer using an applicator, and the solution was applied at 90°C for 20 minutes.
, to form a charge transport layer with a thickness of 15 μm.

The electrophotographic properties of the obtained photoreceptor were measured using an electrostatic recording paper tester (5P-428 manufactured by Kawaguchi Denki), and the results are shown in Table 1.

The initial potential (Vo) in Table 1 indicates the charged potential when a negative 5KN corona is instantaneously discharged, and the dark decay (Vx) indicates the potential decay when left in a dark place for 10 seconds. (Ei.) indicates the light amount value until the potential is halved when 101x white light is irradiated.

In addition, in order to examine the effects of photofatigue, the photoreceptor was
Electrophotographic characteristics immediately after exposure to white light for 10 minutes and the ratio of the initial potential before and after exposure (■.'/
Vo) ttM].

Examples 1 to 3 Predetermined amounts of each of the organic pigments and binders shown in Table 1 were blended and kneaded according to Comparative Examples 1 to 3, and the 7-run coupling agent kF/i) shown in Table 1 was added to the pigment dispersion. Add fines and dissolve. Apply this blood to the applicator 9 on the aluminum plate K11
The sample was dried at 90"C for 15 minutes to form a charge generation layer with a thickness of 1 .mu.m. An fC6 charge transport layer was formed according to Comparative Example 1-3 using the formulation shown in Table 1.The resulting photoreceptor The electrophotographic properties are shown in Table 1.

Examples 4 to 6 Charge generation nodes were formed according to Comparative Examples 1 to 3 using the organic pigments and binders shown in Table 1.

Next, the charge transport substance, binder, and silane coupling agent shown in Table 1 were blended, and charge transport J
− was formed. The electrophotographic properties of the obtained photoreceptor are shown in Table 1.

Examples 7-9 Predetermined amounts of the organic pigment and binder shown in Table 1 were blended.

A predetermined amount of the silane coupling agent shown in Table 1 was added to the round pigment dispersion by kneading according to Comparative Examples 1 to 3, and dissolved in the round pigment dispersion. Apply this coating liquid onto the aluminum plate using an applicator.
Dry at 90°C for 15 minutes to form a charge generation layer with a thickness of 1 μm.

Next, the charge transporting substance, binder, and silane coupling agent shown in Table 1 were blended to form a charge transport layer according to Comparative Examples 1 to 3. The electrophotographic properties of the nine photoreceptors obtained are shown in Table 1.

Comparative Examples 4 to 6 Comparative Examples 1 to 3 were repeated except that the charge generation layer was made thicker. The formulation, film thickness, and electrophotographic properties of each material are shown in Table 2.

Examples 10 to 12 The procedures of Examples 1 to 3 and 7 to 9 were repeated except that the charge generation layer was made thicker. The formulation, film thickness, and electrophotographic properties of each material are shown in Table 2.

Example 13 8FB1.08F, aminosilane [KBM 603] 0
．． 24f, Tetrahydrone Run 2 (+f) was placed in a ball mill (Nippon Kagaku Ceramic Co., Ltd. 3-inch pot...) and kneaded for 1 hour.Next, Silicone Vanice CKR-255) 1
．． 2) 28 cm of tetrahydrofuran was added to the ball mill and kneaded for 3 hours. Its tξ again KR-2550,
967 and Tetrahydro 7 Run 21·t were mixed in a ball mill and kneaded for 4 hours. 111) Apply the J-treated hardening solution onto the aluminum plate using an applicator, and
After drying at 0° C. for 15 minutes, a charge generating layer of t, % l pm was formed.

A charge transporting layer was formed according to Comparative Examples 1 to 3 by blending predetermined amounts of the charge transporting substance and the defoliant shown in Table 3. Table 3 shows the electrophotographic characteristics of the obtained photoreceptor.

Example 14 SFBo, 96N, Mercapto 72N (KBM803)
0.48? , Polyester [Pyro Y20010.36
) and methyl ethyl ketone 20) were placed in a ball mill (3-inch bot mill manufactured by Nippon Kagaku Co., Ltd.) and kneaded for 2 hours. Next, 5 tons of polyester (Vylon 20010.3F, methyl ethyl ketone) was added to the ball mill and kneaded for 4 hours. Then remanufactured polyester [Pyro/200] 0.3P
, methyl ethyl ketone 22? Mix in a ball mill, 3
Kneaded for hours.

The obtained coating solution was applied onto a sialuminum plate using an applicator and dried at 90°C for 15 minutes to a thickness of 1 μm.
A charge generation layer was formed.

Charge transporting substances, binders, and silane coupling agents shown in Table 3 were blended in predetermined amounts to form charge transport layers according to Comparative Examples 1 to 3. Table 3 shows the electrophotographic characteristics of the obtained photoreceptor.

Examples 15-22 Predetermined amounts of the organic pigment and binder shown in Table 4 were blended.

The fI type dispersions kneaded according to Comparative Examples 1 to 3 were prepared as shown in Table 4 and optionally (Example 15.
16 and 19-22) A cyanine dye base and/or a styryl dye base were added and dissolved at a predetermined pitch. This coating liquid is applied onto an aluminum plate using an applicator.
It was dried at 90° C. for 15 minutes to form a charge generation layer with a thickness of 1 μm.

Next, predetermined amounts of the charge-transporting substance, binder, and silane coupling agent shown in Table 4, and optionally (Examples 17 to 22) cyanine dye paste and/or styryl dye paste were blended. A charge transport layer having a thickness of 15 μm was formed according to the method. Table 4 shows the electrophotographic properties of the obtained photoreceptor.

]: Margin Comparative Examples 1 to 3 have a low darkening k (VW) of about 40- as shown in Table 1, light fatigue is large, and (■. There is.

However, it can be seen that in Examples 1 to 9, in which a silane coupling agent was added to at least one of the charge generation layer and the charge transport layer, both dark reduction quality and light fatigue were significantly improved. In contrast, when a silane coupling agent is added to both the charge generation layer and the charge transport layer as seen in Examples 7 to 9, the dark fade after exposure to 12501x white light @tJ is about 50 to 60%.

Light fatigue has improved by about 60 to 70 inches. Incidentally, even when a silane coupling agent is added, there is hardly any decrease in half-exposure 11Eso.

The degree of photofatigue is also influenced by the type of binder in the charge transport layer and the thickness of the charge generation layer.

As shown in Comparative Example 4 of Comparative Example 2, <'dl When polystyrene is used as the binder for the charge transport layer, when the thickness of the layer is 1 μm while the thickness of the charge transport layer is 11t#m, the comparative example using polyester as the binder for the charge transport layer The decrease in (VO') due to photofatigue is relatively small compared to 1. However, when the thickness of charge generation j- becomes thicker, even if polystyrene is used as the binder for charge transport j-, the decrease in (Vo') due to photofatigue is relatively small. The decline is significantly worse (comparison 5 and 6), however.

In this way, even if the thickness of the electric field generation layer becomes thicker, by adding the NRA/V tension ring, which is one of the main factors, the optical fatigue VC can be reduced to an extremely low level.

Dark degradation also becomes better (Practical Examples 10 to 12).

- The method for preparing the poisonous dispersion liquid, which is a liquid for breeding pigeons, includes one ingredient and a binder as shown in Examples 1 to 12.

Solvent and optionally 7-run coupling agent all at once
There are a method of mixing and kneading, and a method of sequentially dispersing V in several steps as shown in Examples 13 and 14, but the latter method is better in dispersing the pigment. Furthermore, the electrophotographic properties of the obtained photoreceptors in rows 13 and 14 of Table 3 are better than those in Examples 2 and 9 by a factor of 1.

On the other hand, as shown in Table 1, even in a system in which a charge generation layer and/or a charge transport (-) 7-rank coupling agent and a cyanine dye base and/or a styryl dye base are used together, electrophotographic properties and photo fatigue shows good values.

As described above, the electrophotographic photoreceptor according to the present invention is a composite type electrophotographic photoreceptor 11 which has excellent photographic characteristics with significantly improved dark decay and optical fatigue.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor having a conductive layer, a charge generation layer containing an organic pigment that generates a charge, and a charge transport layer having charge retention and transport functions, wherein the charge generation layer and the charge transport An electrophotographic photoreceptor comprising at least one of the layers containing a silane coupling agent. 2 Add 0.5% of the upper silane coupling agent into the charge generation layer.
The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor contains up to 40% by weight. 3.47 rank coupling agent in the charge transport layer α05~
Claims 1 and 9 are an electrophotographic photoreceptor according to claim 2, which contains 30% by weight. (4) Claim 1, wherein the silane coupling agent shown above is an aminosilane coupling agent. The electrophotographic photoreceptor according to item 2 or 3. & The electrophotographic photoreceptor according to claim 1, wherein the charge generation layer and/or the charge transport layer contains a cyanine dye paste and/or a styryl dye paste. (a) The charge generating layer contains a silane coupling agent of α5 weight or more and a total of 40 violets or less of a silane coupling agent, a cyanine dye base, and/or a steryl dye paste. The electrophotographic photoreceptor according to item 5. 0.05 silane coupling agent in the 7° charge transport layer
weight - or more and silane coupling agent and cyanine dye base and /l or steryl dye paste in total of 3
Claim 5 tf containing 0 weight or less
I- is the electrophotographic photoreceptor according to item 6.