Electrophotographic photoconductor and electrophotographic image forming apparatus using the photoconductor

An electrophotographic image forming method comprising the steps of:

• providing an electrophotographic photoconductor;
• charging the electrophotographic photoconductor;
• irradiating the electrophotographic photoconductor with imagewise light to form an electrostatic latent image on the electrophotographic photoconductor;
• reversely developing the electrostatic latent image with a toner to form a toner image on the electrophotographic photoconductor;
• transferring the toner image to a receiving material;
• and
• cleaning the electrophotographic photoconductor, wherein the electrophotographic photoconductor comprises an electraconductive substrate, and a charge generating layer including a charge generating material and a charge transporting layer including a charge transporting material, said charge generating layer and charge transporting layer being overlaid and formed overlying one side of the electroconductive substrate, wherein the charge generating material comprises an asymmetric disazo pigment and a metal-free phthalocyanine pigment, and wherein the ratio of the asymmetric disazo pigment to the metal-free phthalocyanine pigment is from 1.5:1 to 5:1 by weight and the asymmetric disazo pigment has the following formula (I):
• Cp1--N.dbd.N--A--N.dbd.N--Cp2 (I)
• wherein A represents a divalent group which is connected to each nitrogen atom of the adjacent azo groups through a carbon atom of said A group;
• and Cp1 and Cp2 independently represents a residual group of a coupler, wherein Cp1 is different from Cp2.

An electrophotographic image forming apparatus comprising:

• an electrophotographic photoconductor;
• a charging device which charges the photoconductor so that the photoconductor has a predetermined potential;
• an imagewise light irradiation device which irradiates the charged photoconductor with imagewise light to form an electrostatic latent image on the photoconductor;
• a developing device which reversely develops the electrostatic latent image with a toner to form a toner image on the photoconductor;
• an image transfer device which transfers the toner image to a receiving material;
• and
• a cleaning device which cleans the photoconductor, wherein the electrophotographic photoconductor comprises an electroconductive substrate, and a charge generating layer including a charge generating material and a charge transporting layer including a charge transporting material, said charge generating layer and charge transporting layer being overlaid and formed overlying one side of the electroconductive substrate, wherein the charge generating material comprises an asymmetric disazo pigment and a metal-free phthalocyanine pigment, and wherein the ratio of the asymmetric disazo pigment to the metal-free phthalocyanine pigment is from 1.5:1 to 5:1 by weight and the asymmetric disazo pigment has the following formula (I):
• Cp1--N.dbd.N--A--N.dbd.N--Cp2 (I)
• wherein A represents a divalent group which is connected to each nitrogen atom of the adjacent azo groups through a carbon atom of said A group;
• and Cp1 and Cp2 independently represents a residual group of a coupler, wherein Cp1 is different from Cp2.