Low color photoconductive insulating compositions comprising nitrogen-free photoconductor and benzopyrilium sensitizer

A coloration resistant photoconductive insulating composition comprising (1) an organic polymeric binder, (2) a nitrogen-free photoconductor of the formula:

• ##STR7## wherein n represents an integer having a value of 0, 1 or
• Ar represents an aryl group;
• each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represents a hydrogen atom, an aryl group, an alkyl group having 1 to about 10 carbon atoms in the alkyl moiety or an alkoxy group having 1 to about 10 carbon atoms in the alkoxy moiety and when n is 0, R.sup.1 and R.sup.4 are both aryl and when R.sup.1 and R.sup.4 are both hydrogen, R.sup.2 and R.sup.3 are aryl and (3) a sensitizer for the photoconductor selected from the group consisting of a benzo[b]pyrylium salt and a benzo[b]thiapyrylium salt.

A coloration resistant photoconductive insulating composition comprising (1) an organic polymeric binder, (2) a nitrogen-free photoconductor of the formula ##STR8## wherein Ar represents an aryl group and each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represents a hydrogen atom, an aryl group, an alkyl group having 1 to about 10 carbon atoms in the alkyl moiety or an alkoxy group having 1 to about 10 carbon atoms in the alkoxy moiety and, when R.sup.1 and R.sup.4 are both hydrogen, R.sup.2 and R.sup.3 are both aryl, and (3) a substantially colorless benzopyrylium type sensitizer for the photoconductor.

An electrophotographic element comprising an electrically conducting support having thereon a coloration resistant photoconductive insulating composition comprising (1) an organic polymeric binder, (2) a photoconductor of the formula:

• ##STR10## wherein n represents an integer having a value of 0, 1 or 2;
• Ar represents an aryl group;
• each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represents a hydrogen atom, an aryl group, an alkyl group having 1 to about 10 carbon atoms in the alkyl moiety or an alkoxy group having 1 to about 10 carbon atoms in the alkoxy moiety and when n is 0, R.sup.1 and R.sup.4 are both aryl and when R.sup.1 and R.sup.4 are both hydrogen, R.sup.2 and R.sup.3 are aryl and (3) a sensitizer for the photoconductor that is selected from the group consisting of a benzo[b]pyrylium salt and a benzo[b]thiapyrylium salt.

An electrophotographic element comprising an electrically conducting support having thereon a coloration resistant photoconductive insulating composition comprising (1) an organic polymeric binder, (2) a nitrogen-free photoconductor of the formula ##STR11## wherein Ar represents an aryl group and each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 represents a hydrogen atom, an alkyl group having 1 to about 10 carbon atoms in the alkyl moiety or an alkoxy group having 1 to about 10 carbon atoms in the alkoxy moiety and, when R.sup.1 and R.sup.4 are both hydrogen, R.sup.2 and R.sup.3 are both aryl, and (3) a substantially colorless benzopyrylium type sensitizer for the photoconductor.