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PERSISTENT PHOTOCONDUCTORS

IP.com Disclosure Number: IPCOM000025395D
Original Publication Date: 1985-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Document File: 2 page(s) / 57K

Publishing Venue

Xerox Disclosure Journal

Abstract

Electron acceptors which function as poor electron transporting materials (electron traps) are converted to persistent photoconductors with polyvinyl carbazole or other donor polymers. A typical example is a complex of poly(N-vinylcarbazole) and difluoroboron-l,3-diphenyl-l,3-propanedionate. This complex is highly colored and absorbs light. Charge transport occurs as a result of hole motion through the carbazole chromophore. It is believed that light absorption produces electron-hole pairs. Electrons are trapped and the holes are free to contribute to conductivity. Since free holes cannot recombine with trapped electrons, the conductivity persists as long as the electrons remain trapped. As electrons are released from traps and recombination proceeds, the persistent conductivity of the photoconductor yrad-ually disappears. It has been found that layers of polyvinylcarbazole complexed with about 30% by weight difluoroboron-l,3-diphenyl-l,3-propanedionate cannot be charged for quite some time after exposure to light is terminated. Thus, these persistent photoconductors may be employed in duplicators where the photore-ceptor is imagewise exposed only once and the remainder of the process comprises charge-develop-clean steps which are repeated as many times as persistence a 110 ws.

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XEROX DISCLOSURE JOURNAL

PERSISTENT PHOTOCONDUCTORS Proposed Glassif ication Damodar M. Pai
430/51 U.S. Dale S. Renfer CI.

Int. Cl. C03g 13/00

Electron acceptors which function as poor electron transporting materials (electron traps) are converted to persistent photoconductors with polyvinyl carbazole or other donor polymers. A typical example is a complex of poly(N-vinylcarbazole) and difluoroboron-l,3-diphenyl-l,3-propanedionate. This complex is highly colored and absorbs light. Charge transport occurs as a result of hole motion through the carbazole chromophore. It is believed that light absorption produces electron-hole pairs. Electrons are trapped and the holes are free to contribute to conductivity. Since free holes cannot recombine with trapped electrons, the conductivity persists as long as the electrons remain trapped. As electrons are released from traps and recombination proceeds, the persistent conductivity of the photoconductor yrad- ually disappears. It has been found that layers of polyvinylcarbazole complexed with about 30% by weight difluoroboron-l,3-diphenyl-l,3-propanedionate cannot be charged for quite some time after exposure to light is terminated. Thus, these persistent photoconductors may be employed in duplicators where the photore- ceptor is imagewise exposed only once and the remainder of the process comprises charge-develop-clean steps which are repeated as many times as persistence a 110 ws.

Volume 10 Number 1 January/February 1985 53...