Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G5/00—Recording-members for original recording by exposure, e.g. to light, to heat or to electrons; Manufacture thereof; Selection of materials therefor
  • G03G5/02—Charge-receiving layers
  • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
  • G03G5/06—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor characterised by the photoconductive material being organic
  • G03G5/0622—Heterocyclic compounds
  • G03G5/0644—Heterocyclic compounds containing two or more hetero rings
  • G03G5/0661—Heterocyclic compounds containing two or more hetero rings in different ring systems, each system containing at least one hetero ring

Definitions

• ABSTRACT A sensitizer for use in an electrophotographic lightsensitive material containing an organic photoconductor comprising a pyrylium salt containing a carbazole nucleus represented by the following general formula wherein R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a haloalkyl group having from 1 to 5 carbon atoms a cyanoalkyl group having from 2 to 6 carbon atoms, a hydroxyalkyl group having 1 to 5 carbon atoms, or an acyl group; R represents a hydrogen atom, a halogen atom or a nitro group, R represents R, represents a hydrogen atom or a hydroxy group; or R and R when taken together form a substituted or unsubstituted benzen
• the present invention relates to a sensitizer for use in an electrophotographic light-sensitive material wherein an organic compound is used as a photoconductor.
• polyvinyl hetero ring compounds represented by poly-N-vinyl carbazole; polynuclear aromatic vinyl polymers such as polyvinylanthracene; low molecular weight compounds having a hetero ring such as an oxazole nucleus, a thiazole nucleus, etc.; and the like, have been used heretofore.
• the present invention provides an absolutely novel sensitizer which, when added to an organic photoconductor, improves not only the light sensitivity but also broadens the wavelength region to which the photoconductor is sensitive. More particularly, the present invention provides a sensitizer comprising a pyrylium salt having a carbazole nucleus.
• synthesis of the various pyrylium salts suitably used in the present invention can be by condensing (A) an ohydroxyarylaldehyde and a carbonyl compound or (B) one molecule of an arylaldehyde and two molecules of a carbonyl compound, in an inert solvent, such as a substituted aromatic hydrocarbon, e.g., nitrobenzene, chlorobenzene, etc., referenced in the above-described literature as one convenient process for synthesizing pyrylium salts.
• an inert solvent such as a substituted aromatic hydrocarbon, e.g., nitrobenzene, chlorobenzene, etc.
• the various pyrylium salts can be synthesized by the above-described reaction (A) using an ohydroxyarylaldehyde represented by the following general formula (III) and a carbonyl group-containing carbazole derivative represented by the following general formula (II), or by the above described reaction (B) using a carbonyl group containing carbazole derivative represented by the following general formula (II) and an arylaldehyde represented by the following general formula (IV).
• Reactions (A) and (B) are schematically described below:
• the reactants are generally used in an equimolar ratio and the reaction is conducted in an inert solvent such as an ester (e.g., ethyl acetate, propyl acetate, butyl acetate, etc.; a cyclic ether (e.g., tetrahydrofuran, etc.) and the like.
• a suitable temperature is from about 1 C to 20C, preferably C to C with reaction times of about 5 minutes to 10 hours, more generally 10 minutes to 1 hour.
• a Lewis acid such as HCl, HBr and H1 is generally present during the reaction.
• reaction (A) represents a hydrogen atom or and R represents a hydrogen atom, a halogen atom (such as a chlorine atom, a bromine atom, an iodine atom or a florine atom), an alkyl group having 1 to 5 carbon atoms (such as methyl, ethyl, propyl, butyl or pentyl), an amino group or an alkylamino group having 1 to 4 carbon atoms (such as ethylamino, methyl amino, propylamino, dimethylamino diethylamino and the like); and Lewis acid represents HCl, HBr, HCIO HNO H 80 BP or BF (C H O; and X represents a Lewis acid residue such as Cl, Br, 1", C10 N0 l-lSOf, or
• HX such as HCl, HBr, HClO HNO H 50 BF or BF ,(C H O wherein X represents a Lewis acid residue such as Cl, Br, C10 N0 H50 or BF ⁇
• HX represents a Lewis acid residue such as Cl, Br, C10 N0 H50 or BF ⁇
• the inventors have experimentally confirmed that, when a hydrogen atom is in the 6-position a triarylmethane dye will be formed under the same reaction conditions.
• R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms (such as methyl, ethyl, propyl, butyl or pentyl), an haloalkyl group having 1 to 5 carbon atoms (such as chloromethyl, chloro-ethyl, chloropropyl, dichloropropyl, chlorobutyl, bromomethyl, bromoethyl, iodomethyl, iodoethyl, fluoromethyl, fluoroethyl, and the like), a cyanoalkyl group having 2 to 6 carbon atoms (such as cyanomethyl, cyanoethyl, cyanopropyl, cyanobutyl, cyanopentyl, and the like), a hydroxyalkyl group having 1 to 5 carbon atoms (such as hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxy
• R represents a hydrogen atom, a halogen atom (such asxachlorine atom, a
• Rgrepresents R represents a hydrogen atom, a halogen atom (such as a chlorine atom, a bromine atom, iodine atom or a florine atom) or an amino group or an alkylamino group having 1 to 4 carbon atoms (such as ethyl amino, methyl amino, propylamino, dimethylamino, diethylamino and the like),'an alkyl group'having l to 5 carbon atoms (such as methyl, ethyl, propyl, butyl or pentyl); and X represents Cl, Br, I, C10 N H80 or BF Preferred substituents for the pyrylium salts of this invention are for R a methyl group, an ethyl group or a hydrogen atom, for R a hydrogen atom or a bromine atom, for R a or
• the reaction time is preferably about 10 minutes to about 1 hour.
• a pyrylium salt is precipitated as crystals.
• the thus formed precipitate is filtered out to obtain the end product pyrylium salt.
• Synthesis Example 2 In the same manner as described in Synthesis Example 1 using 2-hydroxy-a-naphthoaldehyde (ill-6) and 3-acetyl-9-ethylcarbazole (ll-3), a pyrylium salt having the following structural formula was synthesized;
• the absorption maximum wavelength of this compound in chloroform was 547 mu.
• Synthesis Example 3 In the same manner as described in Synthesis Example 1 using 2-hydroxy-5-nitrobenzaldehyde (Ill-5) and 3-acetyl-9-ethylcarbazole (ll-3 a pyrylium salt having the following structural formula was synthesized;
• the absorption maximum wavelength of this compound in chloroform was 574 mu.
• Synthesis Example 4 In the same manner as described in Synthesis Example 1 using 2-hydroxy-a-naphthoaldehyde (III-6) and 3-acetyl-6-bromo-9-ethylcarbazole (ll-8), a pyrylium salt having the following structural formula was synthesized;
• the absorption maximum wavelength of this compound in chloroform was 542 mu.
• this compound On infrared spectral analysis this compound showed a peak at 1665 cm, characteristic of the acetyl group, and the absorption maximum wavelength of the compound in chloroform was 596 mu. Thus, the compound was tinged blue.
• This compound also possesses a sensitizing effect on an organic photoconductive material, and is described in Japanese Patent Application No. 57400/72, (U.S Ser. N0-367,528,filed.lune,6,1973).
• carbazole nucleus-containing pyrylium salts show efficient sensitizing effects on various organic photoconductive materials.
• they are effective fororganic photoconductive materials of 2 the carbazole system such as those described in U.S.
• the sensitizer of the present invention is added to an organic photoconductive material in an amount of based on the weight of the'organic photoconductive material; t 1
• the organic photoconductive materials for "use in 'electro photography, sensitized with the sensitizer'of the present invention can be processed in eithera dry manner or a wet manner. Specific processing procedures thereof are described in U.S. Pat. Nos.
• an organic photoconductive material such 'as poly-N-vinylcarbazole and the pyrylium salts of the present invention are dissolved in an organic solvent such as a halogenated hydrocarbon, e.g., chloroform, methylene chloride, ethylene chloride, and coated on the conductive support so that the dried thickness is about 5 to 50 microns using bar coating.
• an organic solvent such as a halogenated hydrocarbon, e.g., chloroform, methylene chloride, ethylene chloride
• EXAMPLE 1 been subjected to electroconductivity-imparting processing (by coatingthereon Calgonite ConduetiyeP-olymer 261 (trade name'produced'by the Calgon- Corp.
• the thus obtained light-sensitive material wascharge'din the-dark,'imagewise exposed in an exposure amountof 1901-xlsec'using a white light-emitting source.
• a distinct image was reproduced.
• a developer comprising a carrier of nitrocellulose coated glass beads of a particle size of 0.4mm having adsorbed thereon a kneaded mixture of carbon black and polystyrene (5:5' by weight) was used.
• EXAMPLE 2 The pyrylium salt obtained in Synthesis Example 2 was added to 20 g of a poly-N-vinylcarbazole (as described in Example 1), and the sensitizing effect was examined in the same manner as described in Example 1. The results obtained are shown in the following Table 2.
• the thus obtained light-sensitive materials were charged in the dark, exposed to a white light-emitting source through an original image, and subjected to a development processing using a liquid developer prepared by dispersing l g of a commercially available black offset ink of the following composition in 1 liter of cyclohexane.
• alkali blue toner* rosin modified phenol-formaldehyde resin
• R represents R represents a hydrogen atom or a hydroxy group; or R and R when taken together form a substituted or unsubstituted benzene or naphthalene ring, said substituents being an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a nitro group or a halogen atom; R represents a hydrogen atom or R represents a hydrogen atom, a halogen atom, an amino group, an alkylamino group having from 1 to-4 carbon atoms or an alkyl group having 1 to 5 carbon atoms; X represents Cl, Br, I, ClOf, N0 H50 or BF ⁇ .
• the electrophotographic light-sensitive element of claim 1 wherein said sensitizer is 17 18 4.
• the eleetrophotographic light-sensitive element of claim 1 wherein said layer has a dried thickness of from 5 to 50 microns.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Indole Compounds (AREA)
• Photoreceptors In Electrophotography (AREA)

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Cited By (5)

Citations (3)

• 1972
  • 1972-10-17 JP JP47103809A patent/JPS4963439A/ja active Pending
• 1973
  • 1973-10-15 US US406267A patent/US3909260A/en not_active Expired - Lifetime
  • 1973-10-16 GB GB4822573A patent/GB1415950A/en not_active Expired
  • 1973-10-17 DE DE19732352112 patent/DE2352112A1/de active Pending

Patent Citations (3)

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