GB2269677A - Layered organic photoconductive systems comprising a conductive support, a charge generation layer and a charge transport layer - Google Patents

Layered organic photoconductive systems comprising a conductive support, a charge generation layer and a charge transport layer Download PDF

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Publication number
GB2269677A
GB2269677A GB9316306A GB9316306A GB2269677A GB 2269677 A GB2269677 A GB 2269677A GB 9316306 A GB9316306 A GB 9316306A GB 9316306 A GB9316306 A GB 9316306A GB 2269677 A GB2269677 A GB 2269677A
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United Kingdom
Prior art keywords
charge
layer
binder
generation layer
charge generation
Prior art date
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Granted
Application number
GB9316306A
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GB2269677B (en
GB9316306D0 (en
Inventor
Robert L Vollmer
Vernon M Balthis
Ronald A Merten
Bradford L Taylor
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Lexmark International Inc
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Lexmark International Inc
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Publication of GB9316306D0 publication Critical patent/GB9316306D0/en
Publication of GB2269677A publication Critical patent/GB2269677A/en
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Publication of GB2269677B publication Critical patent/GB2269677B/en
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    • 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, 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
    • G03G5/05—Organic bonding materials; Methods for coating a substrate with a photoconductive layer; Inert supplements for use in photoconductive layers
    • G03G5/0528—Macromolecular bonding materials
    • G03G5/0557—Macromolecular bonding materials obtained otherwise than by reactions only involving carbon-to-carbon unsatured bonds
    • G03G5/0564—Polycarbonates

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Photoreceptors In Electrophotography (AREA)

Abstract

An organic photoconductive material comprising a conductive support, a charge generation layer and a charge transport layer, in which the charge generation layer has a binder which is an aromatic ester polycarbonate, has the advantage of being resistant to degradation caused by the liquid in liquid toners. The charge generation layer preferably contains a squarylium dye and the charge transport layer preferably contains a hydrazone in a polycarbonate binder.

Description

LAYERED ORGANIC PHOTOCONDUCTIVE SYSTEMS This invention relates to layered organic photoconductive systems of the type useful in reproduction devices such as copiers and printers.
BACKGROUND OF THE INVENTION Many layered organic photoconductive systems are known in the art.
U. S. Patent No. 3,824,099 describes the use of squarylium dye molecules as photogenerating species in a xerographic photoconductor's charge generating layer.
U. S. Patent No. 4,362,798 shows the use of hydrazones as hole transports in a photoconductor's charge transport layer.
U. S. Patent No. 4,985,326 describes an electroconductive layer and a photosensitive layer. The photosensitive layer contains a binder which may be a polycarbonate copolymer. However, no aromatic ester polycarbonates are mentioned.
U. S. Patent No. 4,840,861 describes the use of a binder in a charge transport layer. The binder may be a mixture of polycarbonate and polyester. However, no copolymers are mentioned.
DISCLOSURE OF THE INVENTION This invention relates to a layered organic photoconductor system which, unlike prior art systems, shows minimal degradation of electrical or print quality factors when used with liquid toners. Currently available organic photoconductive elements, when used with liquid toners, suffer from three major disadvantages: 1) Small molecule hole transport materials are extracted by the liquid in the toner, causing a severe loss of dischargeability, 2) the liquid in the toner attacks the transport binder and leads to poor print quality, and 3) the liquid toner may penetrate to the generation layer, resulting in the disruption of the photoconducting process.
It has now been discovered that these three disadvantages are substantially overcome, most surprisingly, by the use of a unique type of binder in the charge generation layer. It was totally unexpected that the binder in the charge generation layer, which is, of course, overcoated by the charge transport layer, would have such an effect, but that is the experimental fact.
Accordingly, the present invention provides a layered organic photoconductive system comprising the successive layers (a) a conducting substrate, (b) a charge generation layer which comprises a dye dispersed in a binder, and (c) a charge transport layer, with the improvement according to which the binder in the charge generation layer is an aromatic ester polycarbonate.
Aromatic ester polycarbonates are commercially available materials. Various methods for their synthesis are shown in U. S. Patents No. 4,330,662; 3,169,121; 3,459,570; 3,053,810; 3,030,331 and 3,220,976.
In a preferred embodiment of the present invention, the photoconductive element is prepared as follows: A charge generating layer is first coated on an aluminum surface, the charge generating material being a dispersion of an aromatic ester polycarbonate binder, for example, Mobay Co. brand DP-9, and 2,4-di-(m-hydroxy N, N-dimethylamino-phenyl) cyclobutene diylium-1,3- diolate(hydroxy squarylium dye) This charge generating layer is then coated with a hole transporting layer composed of a 60/40 mixture of p-diethylaminobenzaldehyde-l, l-diphenylhydrazone (DEH) and a poly(carbonate), for example, Mobay Co. brand MPG 3408 or Mitsubishi Gas Co. brand Iupilon.This combination of layers has the advantage of being unaffected by either branched (Isopar brand) or straight chain (Norpar-13 brand) hydrocarbon oils, of the type used in liquid toners. By comparison, a prior art photoconductive element was rendered inoperative by both branched and straight chain hydrocarbon oils.
Additional details of the above preparation of the photo-conductor are as follows: In the preparation of the charge generating layer, 136.78 grams of the hydroxy squarylium dye were mixed with 492.38 grams of aromatic ester polycarbonate (Mobay brand DP-9), 54.76 grams of cellulose acetate butyrate and 2,572.84 grams of tetrahydrofuran. The mixture was milled and then an additional 13,841.24 grams of tetrahydrofuran was added.
This formulation was then coated on an anodized aluminum drum.
The preparation of the charge transport formulation is as follows: 92.66 grams of DEH, 138.01 grams of polycarbonate (MPG3408 from Mobay Co), 767.46 grams of tetrahydrofuran, 1.67 grams of Acetosol Yellow (a proprietary dye of Sandoz Co.), and 0.20 grams of silicone oil were mixed.
This formulation was then coated on the charge generation layer to produce the finished drum photoconductor element.
It should be understood that the foregoing example has been given solely for purposes of illustration, and should not be construed as a limitation on the present invention, many variations of which will occur to those skilled in the art, without departing from the spirit or scope thereof.
In general the charge transport layer is about 20 to 25 microns thick and the charge generation layer about 0.2 to 0.5 microns thick. The preferred electrically conductive substrate is aluminum, particularly anodized aluminum. Although it is preferred for use on an aluminum drum, the photoconductive system of the present invention is suitable for use on other substrates, for example aluminum coated plastic, such as polyethylene terphthalate.

Claims (6)

CLAIMS:
1. -A layered organic photoconductive system comprising the successive layers (a) a conductive substrate, (b) a charge generator layer which comprises a dye dispersed in a binder, and (c) a charge transport layer, characterised in that the binder in the charge generation layer is an aromatic ester polycarbonate.
2. A photoconductive system as claimed in claim 1 wherein the conductive substrate is an aluminum drum.
3. A photoconductive system as claimed in claim 1 or claim 2 wherein the dye in the charge generation layer is a squarylium dye.
4. A photoconductive system as claimed in any preceding claim wherein the charge transport layer comprises a hydrazone dispersed in a polycarbonate binder.
5. A layered photoconductive system comprising in successive layers: (1) an electrically conductive substrate, (2) a charge generating layer which comprises a squarylium dye dispersed in an aromatic ester polycarbonate binder, and (3) a charge transporting layer comprising a hydrazone in a polycarbonate binder.
6. A layered organic photoconductor system as claimed in claim 5 wherein the substrate is an aluminum drum.
GB9316306A 1992-08-06 1993-08-05 Layered organic photoconductive materials Expired - Fee Related GB2269677B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US92660092A 1992-08-06 1992-08-06

Publications (3)

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GB9316306D0 GB9316306D0 (en) 1993-09-22
GB2269677A true GB2269677A (en) 1994-02-16
GB2269677B GB2269677B (en) 1996-04-24

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GB9316306A Expired - Fee Related GB2269677B (en) 1992-08-06 1993-08-05 Layered organic photoconductive materials

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0754977A1 (en) * 1995-07-07 1997-01-22 Lexmark International, Inc. Electrophotographic photoconductor having improved cycling stability and oil resistance
EP0767411A1 (en) * 1995-10-06 1997-04-09 Lexmark International, Inc. Electrophotographic photoconductor for use with liquid toners
EP1155356A1 (en) * 1999-01-27 2001-11-21 Lexmark International, Inc. Charge transport layers comprising hydrazones and photoconductors including the same

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0415864A1 (en) * 1989-08-31 1991-03-06 Lexmark International, Inc. Electrophotographic photoconductor
EP0427890A1 (en) * 1989-11-13 1991-05-22 Agfa-Gevaert N.V. Photoconductive recording element
US5130215A (en) * 1989-08-31 1992-07-14 Lexmark International, Inc. Electrophotographic photoconductor contains ordered copolyester polycarbonate binder

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0415864A1 (en) * 1989-08-31 1991-03-06 Lexmark International, Inc. Electrophotographic photoconductor
US5130215A (en) * 1989-08-31 1992-07-14 Lexmark International, Inc. Electrophotographic photoconductor contains ordered copolyester polycarbonate binder
EP0427890A1 (en) * 1989-11-13 1991-05-22 Agfa-Gevaert N.V. Photoconductive recording element

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0754977A1 (en) * 1995-07-07 1997-01-22 Lexmark International, Inc. Electrophotographic photoconductor having improved cycling stability and oil resistance
EP0767411A1 (en) * 1995-10-06 1997-04-09 Lexmark International, Inc. Electrophotographic photoconductor for use with liquid toners
EP1155356A1 (en) * 1999-01-27 2001-11-21 Lexmark International, Inc. Charge transport layers comprising hydrazones and photoconductors including the same
EP1155356A4 (en) * 1999-01-27 2005-03-02 Lexmark Int Inc Charge transport layers comprising hydrazones and photoconductors including the same

Also Published As

Publication number Publication date
GB2269677B (en) 1996-04-24
GB9316306D0 (en) 1993-09-22

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20010805