JPH0416853A - 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 is an optionally substituted aliphatic hydrocarbon group, such as a methyl, ethyl, or propyl group, aryl, such as a phenyl or p-dimethyl-aminophenyl group, or a heterocyclic group, such as N-methyl-2-pyrrolyl or 2-thienyl group, and each of Z1 - Z4 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 difficult to dispose of because it is toxic. Electrophotographic photoreceptors in which zinc oxide is dispersed in a 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 is general 2+I)
This is shown in .

(However, in the formula, R1 represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, and Zl, Z2
, Z3 and Z4 represent substituted or unsubstituted cyclic hydrocarbon residues or heterocyclic residues. ) The aliphatic hydrocarbon groups represented by R1 include methyl group, ethyl group, propyl group, n-butyl group, isobutyl group, tertiary-butyl group, 5-methyldodecyl group, trifluoromethyl group, 3-
Phenyloctyl group, vinyl group, nipropenyl group, impropenyl group, 1-butenyl group, 2-butenyl group, 2
-pentenyl group, ethynyl group, etc. Aryl groups include phenyl group, p-dimethylaminophenyl group, p-ethylmethylaminophenyl group, 3-methylazo-4-dimethylaminophenyl group, o-ethylphenyl group, 3.5-dichlorophenyl group, 1-naphthyl group. ,1
-Methyl-2-naphthyl group and the like. As the heterocyclic group, N-methyl-2-pyrrolyl group, 2-thienyl group,
2-furyl group, 2-pyridyl group, 2-quinolyl group, N-
Examples include methyl-4-piperidyl group and piperidino group. Examples of the cyclic hydrocarbon residues represented by Zl, Z2, z3, and Z4 include those shown in Table 1. Examples of the heterocyclic residue include those shown in Table 2.

Table 1 (Part 1) Table 1 (Part 2) Table (Part 3 Table (Part 5) Table (Part 4) Table (Part 1 Table (Part 4) Table (Part 3) Table (Part 5) (Part 6 (Part 8 Table) (Part 7) This squareium pigment is shown by the following structural formula 3,
It is obtained by reacting 4-dihydroxy-3-cyclobutene-1,2-dione with an azo compound represented by the following general 2@) 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 represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, and Zl, Z2
, Z3 and Z4 represent substituted or unsubstituted cyclic hydrocarbon residues or heterocyclic residues. ) 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 103. 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 its thickness is from 0.1 μm to 1.0 μm, especially from 0.1 μm to 1.0 μm.
．． The thickness is preferably 3 μm to 1.0 μm. 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 ground in 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 paraffin, chlorinated biphenyl, phosphate plasticizer, etc. can be used. The plasticizer is used in an amount of 20% by weight or less based on the binder resin, within a range that does not impair the properties of the photoreceptor. When a squareium pigment dispersed in a binder resin is used, the charge generation layer is formed by a spray method, a barcoder method, or the like.

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 General formula (I [I) R1 is a methyl group, Zl, Z2, Z
3. 1 mmol of an azo compound in which Z4 is a cyclic hydrocarbon residue 10, 70.5 mmol of 3,4-dihydroxy-3-cyclobutene-1,2-dio, and benozene I
Qm/! , n-butanol in 20 mJ at 120°C to 125°C for 15 hours while water produced during the reaction was azeotropically distilled off. The generated precipitate was collected by filtration to obtain Squarium Pigment 1 represented by the following structural formula in a yield of 349%. The results of elemental analysis of this product are shown in Table 3.

Table 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 (Part 2) Table (Part 3) Example 26 Polyester resin cyclohexanone 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 0.1 μm.

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

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 as ■. was measured. Next, the photosensitive layer was irradiated with light at an illuminance of 5 lux using a tungsten-halogen lamp, and the time required for the surface potential to reach vo of 172 was measured to determine the half-reduced exposure amount E1/2. As a result, the surface potential■
. is -650V, and the half-decreased exposure amount El/2 is 371u
It was x seconds.

Examples 27-50 Squareium pigments 2-2 synthesized in Examples 2-25
A laminated electrophotographic photoreceptor was prepared using Example 5 in the same manner as in Example 26, and its electrical characteristics were measured. Table 7 shows the results.
Shown below.

Table (Part 1) Table 7 (Part 2) Table 7 (Part 3) Examples 51 to 75 Add 100% by weight of diethylaminobenzaldehyde diphenylhydrazone to polycarbonate resin, apply this on an aluminum substrate, and apply charge transport to a film thickness of 20 μm. formed a layer.

Polyester resin cyclohexanone 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 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, this photoreceptor was subjected to corona discharge of 6 kV for 2 seconds using a paper analyzer, and then left in a dark place for 2 seconds, and the surface potential V0 at that time was measured. Next, the photosensitive layer was irradiated with light at an illuminance of 5 Ilux 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.

(Part 1 (Part 3 Table (Part 2)) Example 76 The photoreceptor produced in Example 26 was coated with a wavelength of 450 nm and a wavelength of 550 nm.
nm, 650 nm, 750 nm, 850 nm.

When each monochromatic light was irradiated with 1 μW/era and the half-reduction 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 [Effects of the Invention] The electrophotographic photoreceptor of the present invention can be used in all electrophotographic processes currently used.

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

[Brief explanation of the drawing]

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.

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 represents a substituted or unsubstituted aliphatic hydrocarbon group, aryl group, or heterocyclic group, and Z1, Z2
, Z3 and Z4 represent substituted or unsubstituted cyclic hydrocarbon residues or heterocyclic residues. )