The carbon nanotube materials improve photoreceptor wear resistance. A protective overcoat layer can be provided over the photogenerating layer (or other underlying layer). Various overcoating layers can be used as long as the functional properties of the photoreceptor are not adversely affected.
Another benefit of the use of self-assembled carbon nanotube materials with pendant charge transport materials in charge transport layers is that the materials exhibit very high charge transport mobility. Accordingly, the use of self-assembled carbon nanotube materials having pendant charge transport materials in a charge transport layer can provide charge transport speeds that are orders of magnitude higher than charge transport speeds provided by conventional charge transport materials.
For example, the charge transport mobility in a charge transport layer comprising self-assembled carbon nanotube materials having pendant charge transport materials can be 1, 2, 3, 4, 5, 6, 7, or more, such as about 1 to about 4, orders of magnitude higher as compared to a comparable charge transport layer that includes a similar amount of conventional pyrazoline, diamine, hydrazones, oxadiazole, or stilbene charge transport small molecules. This resultant dramatic increase in charge mobility can result in significant corresponding improvements in the printing process and apparatus, such as extreme printing speeds, increased print quality, and increased photoreceptor reliability.
In electrophotography, also known as Xerography, electrophotographic imaging or electrostatographic imaging, the surface of an electrophotographic plate, drum, belt or the like (imaging member or photoreceptor) containing a photoconductive insulating layer on a conductive layer is first uniformly electrostatically charged. The imaging member is then exposed to a pattern of activating electromagnetic radiation, such as light. The radiation selectively dissipates the charge on the illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image on the non-illuminated areas.
This electrostatic latent image may then be developed to form a visible image by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer. The resulting visible image may then be transferred from the imaging member directly or indirectly (such as by a transfer or other member) to a print substrate, such as transparency or paper. The imaging process may be repeated many times with reusable imaging members.
The charge transport layer comprises self-assembled carbon nanotube materials having pendant charge transport materials. That is, in an unassembled starting form, carbon nanotube units comprise a nanotube self-assembling moiety containing a charge transport material attached thereto. The carbon nanotube units with pendant charge transport materials are then self-assembled, in a two-dimensional and three-dimension fashion, to provide carbon nanotube materials having pendant charge transport materials.
In the assembled form, the carbon nanotube material can have the pendant charge transport materials located either inside the nanotube, outside the nanotube, or both inside and outside the nanotube, although having the charge transport materials located only outside the nanotube is desired in embodiments in consideration of desired charge transport properties through the material. The carbon nanotube material itself can be either electrically conductive or electrically insulating, although electrically neutral materials are desired in embodiments.