JPH0416851A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sufficient spectral sensitivity in a wide wavelength region by incorporating a specified squarium pigment. CONSTITUTION:The photosensitive body contains the squarium pigment represented by formula I in which each of R1 - R4 is H, halogen, optionally substituted aliphatic hydrocarbon group, alkoxy, amino, aryl, or a heterocyclic group; R5 is an optionally substituted aliphatic hydrocarbon group or aryl or heterocyclic group; and each of Z1 and Z2 is an optionally substituted cyclic hydrocarbon group or heterocyclic group, thus permitting sufficient spectral sensitivity in the wide wavelength region from the visible region to the near infrared region to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor used in an electrophotographic process. More specifically, the present invention relates to an electrophotographic photoreceptor containing a squareium pigment represented by the general formula (I).

[Problem to be solved by the invention]

Conventionally, amorphous selenium,
Inorganic photosensitive materials such as cadmium sulfide and zinc oxide, and organic photosensitive materials such as azo compounds and squareium pigments are widely known.

It is well known that amorphous selenium and the like have excellent properties as materials for electrophotographic photoreceptors and are in practical use. However, this electrophotographic photoreceptor is toxic and therefore difficult to dispose of. Electrophotographic photoreceptors in which zinc oxide is dispersed in resin have poor mechanical strength and cannot withstand repeated use.

Although organic photosensitive materials are excellent in processability such as film formation, no material with sufficient sensitivity has been obtained as a photoreceptor for electrophotography.

The object of the present invention is to solve such conventional problems and to provide an electrophotographic photoreceptor that can be used in all currently used electrophotographic processes, and that has sufficient performance in a wide wavelength range from the visible region to the near-infrared region. An object of the present invention is to provide an electrophotographic photoreceptor having a high spectral sensitivity.

[Means to solve the problem]

The squareium pigment used in the present invention has the general formula (I)
It is indicated by.

(However, in the formula, R1%R2, R3, and R4 represent a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an alkoxy group, an amine group, an aryl group, a heterocyclic group, or a hydroxyl group, and R5 is a substituted or represents an unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, Zl, Z2
represents a substituted or unsubstituted cyclic hydrocarbon residue or a heterocyclic residue. ) Examples of the halogen atoms represented by R1, R2, R3, and R4 include fluorine, chlorine, bromine, and iodine.

Examples of the alkoxy group include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, pentyloxy group, and benzyloxy group. Examples of amino groups include methylamino group, ethylamino group, propylamino group, isopropylamino group, butylamino group, isobutylamino group, tertiary-butylamino group, 3-phenyloctylamino group, ethylphenylamino group, dimethylamino group, diethylamino group, dipropylamino group,
Examples include diisopropylamino group and di-3-phenyloctylamino group.

The aliphatic hydrocarbon groups represented by R1, R2, R3, R4, and R5 include methyl group, ethyl group, propyl group, n-butyl group, isobutyl group, tertiary-butyl group, 5
-Methyldodecyl group, trifluoromethyl group, 3-phenyloctyl group, cyclopropyl group, cyclopentyl group, hinyl group, 1-propenyl group, isopropenyl group, 1
-butenyl group, 2-butenyl group, 2-pentenyl group, 1
-cyclohexenyl group, ethynyl group, etc.

Aryl groups include phenyl group, p-dimethylaminophenyl group, p-ethylmethylaminophenyl group, o-ethylphenyl group, 3-methylazo-4-dimethylaminophenyl group, 3.5-dichlorophenyl group, l-naphthyl group. , 1-methyl-2-naphthyl group, and the like. As the heterocyclic group, N-methyl-2-pyrrolyl group, 1,5-
Dimethyl-2-? Examples include lolyl group, 2-thienyl group, 2-cenyl group, 2-furyl group, furfuryl group, 2-pyridyl group, 2-quinolyl group, N-methyl-4-piperidyl group, piperidino group, and the like. Examples of the cyclic hydrocarbon residues represented by Zl and Z2 include those shown in Table 1. Examples of the heterocyclic residue include those shown in Table 2.

Table 1 (Part 1) Table (Part 2 Table (Part 4) Table (Part 3) Table (Part 5 Table (Part 1) Table (Part 3 Table (Part 2) Table (Part 4) Table (Part 5 Table (Part 7 Table) (Part 6) Table (Part 8) This squareium pigment is 3 shown by the following structural formula 0,
It is obtained by reacting 4-dihydroxy-3-cyclobutene-1,2-dione with an azo compound represented by the following general formula ([[) in a solvent. Examples of the solvent include aliphatic alcohols such as methanol, ethanol, propatool, butanol, amyl alcohol, and the like.

(However, in the formula, R1, R2, R3, and R4 represent a hydrogen atom, a halogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, an alkoxy group, an amino group, an aryl group, a heterocyclic group, or a hydroxyl group, and R5 is a substituted or represents an unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, Zl, Z2
represents a substituted or unsubstituted cyclic hydrocarbon residue or a heterocyclic residue. ) Cross-sectional views of the electrophotographic photoreceptor of the present invention are shown in FIGS. 1 to 3.

FIG. 1 is a sectional view of a laminated electrophotographic photoreceptor in which a charge generation layer 102 is formed on a conductive support 101 and a charge transport layer 103 is formed on the charge generation layer 102. Second
The figure is a cross-sectional view of a laminated electrophotographic photoreceptor in which a charge transport layer 103 is formed on a conductive support 101 and a charge generation layer 102 is formed on the charge transport layer 106. In the laminated electrophotographic photoreceptor shown in FIGS. 1 and 2, a charge generation layer 102 and a charge transport layer 103 form a photosensitive layer 104. FIG. 3 is a cross-sectional view of a single-layer electrophotographic photoreceptor in which a photosensitive layer 104 is formed on a conductive support 101.

The charge generation layer is formed on the conductive support or on the charge transport layer, and has a thickness of 0.1 μm to 1° μm, particularly 0.1 μm to 1 μm.
3 μm to 1. Ott m is preferred. To form the charge generation layer, a squareium pigment generally represented by (I) is used alone, or a mixture of this squareium pigment dispersed in a binder resin is used. When a squareium pigment is used alone, a charge generation layer is formed by solvent spraying or vacuum deposition. When a squareium pigment dispersed in a binder resin is used, the ratio of the squareium pigment to the binder resin is 10% to 90% by weight, preferably 25% to 30% by weight. In this case, the squareium pigment is thoroughly pulverized using a ball mill or paint conditioner and dispersed in the binder resin. As the binder resin, for example, photoconductive polymers such as polyvinylcarbazole, polyvinylcarbazole derivatives, polyvinylnaphthalene, polyvinylanthracene, polyvinylpyrene, and other organic matrix materials having charge transport ability can be used. Insulating resins that do not exhibit photoconductivity, such as polystyrene, polyester, polycarbonate, and derivatives thereof, can also be used. At this time, in order to improve the strength of the photoreceptor, a plasticizer can be used in the same manner as in general polymer materials. As the plasticizer, chlorinated halaffin, chlorinated biphenyl, phosphate plasticizer, etc. can be used. The plasticizer can be used in an amount of 20% by weight or less based on the binder resin, as long as it does not impair the characteristics of the photoreceptor. When using a pigment in which the squareium pigment is dispersed in the binder resin, spraying, barcoding, etc. A charge generation layer is formed by a method such as a method.

As the material of the conductive support, for example, aluminum, nickel, zinc, platinum, gold, stainless steel, brass, iron, palladium, etc. can be used.

A charge transport layer is provided on the charge generation layer or conductive support. As charge transport substances, carbazole derivatives,
Examples include pyrazoline derivatives, triphenylamine, hydrazone derivatives, polyvinylpyrene, polyvinylanthracene, and polyvinylacridine. These charge transport materials can be used alone or in combination of two or more.

As the binder resin used in the charge transport layer, polymers such as acrylic resin, polystyrene, polyester, polyarylate, polysulfone, and polycarbonate can be used. At this time, the ratio of the charge transport material to the binder resin is 150% by weight or less.

〔Example〕

Hereinafter, the electrophotographic photoreceptor of the present invention will be described in more detail based on Examples.

Example 1 In general formula (III), R1% R2, R3, R4 are hydrogen atoms, R5 is a methyl group, Zl, Z2 are cyclic hydrocarbon residues 10
1 mmol of the azo compound represented by 3゜4-dihydroquine-3-cyclobutene-1,2-dione
r1rrIOl was reacted in 1 Q ml of benzene and Z Q ml of n-butanol at 120°C to 125°C while water produced during the reaction was distilled off azeotropically.

The generated precipitate was collected by filtration to obtain Squarium Pigment 1 represented by the following structural formula in a yield of 356%. The results of elemental analysis of this product are shown in Table 3.

Examples 2 to 25 Squareium pigments 2 to 25 shown in Table 4 were synthesized by carrying out the reaction in the same manner as in Example 1 except that the azo compound was changed. The yields of Squarium pigments 2 to 25 are shown in Table 5.
Table 6 shows the results of elemental analysis.

Table (Part 1 Table 6 (Part 2) Table 6 (Part 3) Example 26 Polyester resin link a hexanone solution 5% by weight, 2
0.48 mmol of Squarium Pigment 1 synthesized in Example 1 was added to 0 ml, and this was dispersed while being pulverized for 1 hour using a paint conditioner. Next, this was applied onto an aluminum substrate using an applicator to form a charge generation layer having a thickness of 03 μm to 10 μm (7).

100% by weight of dimethylaminobenzaldehyde diphenylhydrazone was added to a polycarbonate resin, and this was applied onto the charge generation layer to form a charge transport layer with a thickness of 20 μm, thereby producing a laminated electrophotographic photoreceptor.

A corona discharge of 16 kV was applied to this photoreceptor for 2 seconds using a paper analyzer, and then it was left in a dark place for 2 seconds, and the surface potential at that time was measured. was measured. Next, the photosensitive layer was irradiated with light at an illuminance of 5 lux using a tungsten-halogen lamp, and its surface potential became ■. The time required for the amount to decrease to 1/2 was measured, and the half-reduction exposure amount E1/2 was determined. As a result, the surface potential■. is -650V, and the half-decreased exposure amount El/24'! ,
It was 3.41 ux·sec.

Examples 27 to 50 Laminated electrophotographic photoreceptors were prepared using the squareium pigments synthesized in Examples 2 to 25 in the same manner as in Example 26, and their electrical properties were measured.

The results are shown in Table 7.

Table 7 (Part 1) Table 7 (Part 2) Examples 51 to 75 Paradiethylaminobenzaldehyde diphenylhydrazone was added to polycarbonate resin K in an amount of 100% by weight, and this was coated on an aluminum substrate to form a charge transport layer with a thickness of 20 μm.

Polyester resin cyclohexanone solution 5% by weight, 2
Add 0 of the squareium pigment synthesized in Example 1 to Qml.
．． 48 mmol was added, and this was dispersed in the binder resin while crushing the squareium pigment using a paint conditioner for 1 hour. Next, this was applied onto the charge transport layer using an applicator to form a charge generation layer having a thickness of 03 μm to 1.0 μm, thereby producing a laminated electrophotographic photoreceptor.

Next, a corona discharge of 6 kV was applied to this photoreceptor for 2 seconds using a paper analyzer, and then it was left in a dark place for 2 seconds, and the surface potential at that time was measured. was measured. Next, the photosensitive layer was irradiated with light with an illuminance of 5 lux using a tungsten-halogen lamp, and its surface potential became ■. The time required for the amount to decrease to 1/2 was measured, and the half-reduction exposure amount E1/2 was determined. Table 8 shows the results.
Shown below.

Electrophotographic photoreceptors were also produced using Squarium Pigments 2 to 25 in the same manner as in Example 51, and their electrical properties were measured. The results are shown in Table 8.

Table 8 (Part 1) Table 8 (Part 2) Example 76 The photoconductor produced in Example 26 was exposed to a wavelength of 450 nm and a wavelength of 550 nm.
When monochromatic light of nm, 650 nm, 750 nm, and 850 nm was irradiated at 1 μW/d, and the half-life exposure amount E1/2 was determined, the results shown in Table 9 were obtained. As can be seen from Table 9, the electrophotographic photoreceptor of the present invention has sufficient spectral sensitivity in a wide wavelength range.

Table 9 It also has sufficient spectral sensitivity in a wide wavelength range from the visible region to the near-infrared region at °C.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of the electrophotographic photoreceptor of the present invention. 101... Conductive support, 102... Charge generation layer, 103... Charge transport layer, 104... Photosensitive layer. 〔Effect of the invention〕

Claims (1)

[Claims] An electrophotographic photoreceptor characterized by containing a squarium pigment represented by the general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (However, in the formula, R1, R2, R3, and R4 are hydrogen atoms, halogen atoms, substituted or unsubstituted aliphatic hydrocarbon groups, alkoxy groups, amino group, aryl group, heterocyclic group, or
represents a hydroxyl group, R5 represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, Z1, Z
2 represents a substituted or unsubstituted cyclic hydrocarbon residue or a heterocyclic residue. )