A charge generation material for an electrophotographic photoconductor includes a titanyloxyphthalocyanine molecular aggregate. The titanyloxyphthalocyanine molecular aggregate contains between 0.006 to 1.000 water molecules per titanyloxyphthalocyanine molecule. The titanyloxyphthalocyanine molecular aggregate exhibits an X-ray diffraction spectrum, measured using CuK.alpha. radiation, having clear peaks at angles of 7.2.degree., 9.6.degree., 11.6.degree., 13.4.degree., 14.9.degree., 18.3.degree., 23.6.degree., 24.1.degree. and 27.3.degree., the peak at 9.6.degree. being the highest, the spectrum lacking a peak at 26.3.degree., and the angles being 2 .theta..+-.0.2.degree., where .theta. is a diffraction angle. A function-separation-type electrophotographic photoconductor includes the titanyloxyphthalocyanine molecular aggregate of the present invention in the charge generation layer. A monolayer-type electrophotographic photoconductor includes the titanyloxyphthalocyanine molecular aggregate of the present invention in the photoconductive layer.
Oxytitanium phthalocyanine having a novel crystal form having excellent electrophotographic properties, such as a high charge potential, a high sensitivity and stable performances free from causing changes in various properties in repeated use, can be produced in the absence of a halogen substance, by carrying out the crystal transformation of amorphous oxytitanium phthalocyanine in a solvent comprising water and naphthalene.
An object of the invention is to implement a photoreceptor having high sensitivity and faithfully realizing high-density recording. An electrophotographic photoreceptor used for an image forming apparatus for forming a latent image at a resolution of 1200 dpi or more by exposing an object to light and visualizing the latent image with a reversal development system using a toner having an average particle size of 6 .mu.m or less, which comprises an electrically conductive support, and a photosensitive layer composed of a charge generating layer formed on the electrically conductive support, and a charge transport layer formed on the charge generating layer, having a thickness of 20 .mu.m or less.
An object of the invention is to obtain an electrophotographic photoreceptor having high sensitivity, high image quality, high stability and high resolution. A charge generating layer of the electrophotographic photoreceptor contains, as a charge generating substance, a crystalline titanyl phthalocyanine composition exhibiting, in an X-ray diffraction spectrum of a CuK.alpha. characteristic X-ray (wavelength: 1.5418 .ANG.), at least four diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 10.0.degree. or lower, and a diffraction peak at a Bragg angle of 27.2.degree. having an intensity smaller than the maximum diffraction intensity of the four diffraction peaks, or a lowly crystalline titanyl phthalocyanine composition exhibiting a diffraction peak having the maximum diffraction intensity at a Bragg angle (2.theta..+-.0.2.degree.) of 27.3.degree.. A charge transporting layer of the electrophotographic photoreceptor contains, as a charge transporting substance, a bisamine compound.
