Electrophotoreceptor using hydrazone as the charge transport material

DETAILED DESCRIPTION OF THE INVENTION It was unexpectedly found that high sensitivity, low residual potential and excellent durability can be realized on a electrophotoreceptor by employing a specific group of hydrazone compounds as the charge transport material.
The individual elements of the present invention are described in detail below.
The hydrazone compounds contemplated by the present invention are compounds of formula (I): ##STR2## in which R.
sup.
1 represents substituted or unsubstituted C.
sub.
1 -C.
sub.
4 alkyl, R.
sub.
2 represents hydrogen, alkyl or alkoxy, R.
sub.
3 and R.
sub.
4 independently represent substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group or substituted or unsubstituted aralkyl group, or together with the bonded nitrogen atom represent substituted or unsubstituted aromatic heterocyclic ring.
A preferred group of hydrazone compounds contemplated by the present invention are compounds of formula (I) in which at least one of R.
sub.
3 and R.
sub.
4 is an aryl group.
A more preferred group of hydrazone compounds contemplated by the present invention are compounds of formula (I) in which R.
sub.
1 represents ethyl and R.
sub.
2 represents hydrogen.
A group of most preferred hydrazone compound contemplated by the present invention are compounds as follows: ##STR3## The hereinabove described hydrazone compounds can be produced by conventional methods.
For example, the hydrazone compounds can be obtained by reacting equimolar aldehyde and hydrazine in a suitable solvent using an organic or inorganic acid as the catalyst.
Hydrazine is frequently added in excess to ensure complete reaction and ease of purification.
The solvents commonly employed include alcohol, acetic acid and tetrahydrofuran.
In the production of an electrophotoreceptor according to the present invention, the conductive substrate is coated with the described charge generation layer and then the charge transport layer.
The charge generation layer is applied by coating on the conductive substrate a solution containing a charge generation material and a polymeric binder followed by drying said dispersion