Abstract: Provided are an electrophotographic photoconductor which shows a small variation in sensitivity and exhibits a high sensitivity even at a small amount of light exposure and a tandem-system color image forming device provided with the electrophotographic photoconductor. A positive charging type electrophotographic photoconductor for use in a tandem-system color image forming device including a drum type electrophotographic photoconductor, a rotation speed of which is (70) rpm or more, and a color image forming device provided with the electrophotographic photoconductor, wherein, when Vb (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 0.6 ?J/cm2 and Va (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 1.5 ?J/cm2, a sensitivity ratio represented by Vb/Va is adjusted to a value of below (2).

Abstract: There is provided a tandem color image forming apparatus and the like, which is capable of suppressing the generation of black spots during a continuous image forming process, even though a non-magnetic single-component developer is used and a cleaner-less type is adopted. The color image forming apparatus is a tandem type that includes a plurality of image carriers and a cleaner-less type that does not include a blade cleaner, wherein the resistance per square centimeter of a base body of an image carrier using for at least a black developer among the plurality of image carriers, or the resistance per square centimeter of the base body through an intermediate layer is set in a range of 1×105 to 1×108? or more.

Abstract: The present invention provides a monolayer type electrophotographic photoconductor which can effectively suppress the generation of an exposure memory and exhibits high sensitivity and an image forming apparatus using the monolayer type electrophotographic photoconductor. In an electrophotographic photoconductor which has a monolayer type photoconductive layer including at least a charge generating agent, a hole transfer agent, an electron transfer agent and a binding resin on a substrate, the charge generating agent contains oxo-titanyl phthalocyanine crystal, the electron transfer agent has a reduction potential thereof set to a value which falls within a range from ?0.97 to ?0.83 V, and the reflection absorbance (A/?) of the photoconductive layer with respect to light having a wavelength of 700 nm, a film thickness (d/m) of the photoconductive layer, and the concentration (C/weight %) of the oxo-titanyl phthalocyanine crystal of the photoconductive layer (100 weight %) satisfy a following formula (1).

Abstract: The present invention provides an electrophotographic photoconductive member comprising a substrate, and a photoconductive layer containing a hole transferring material, a charge generating material and a binder resin, wherein a value (IV/OV value) in which the inorganic value is divided by the organic value of the binder resin is 0.

Abstract: There is provided a tandem color image forming apparatus and the like, which is capable of suppressing the generation of black spots during a continuous image forming process, even though a non-magnetic single-component developer is used and a cleaner-less type is adopted. The color image forming apparatus is a tandem type that includes a plurality of image carriers and a cleaner-less type that does not include a blade cleaner, wherein the resistance per square centimeter of a base body of an image carrier using for at least a black developer among the plurality of image carriers, or the resistance per square centimeter of the base body through an intermediate layer is set in a range of 1×105 to 1×108? or more.

Abstract: Provided is a monolayer type photoconductor superior in sensitivity characteristics that allows reliable production by easy confirmation of the sensitivity characteristics, and an image forming device using such a monolayer type photoconductor. A monolayer type photoconductor including a base body and a single photo sensitive layer formed on the base body, the single photo sensitive layer containing a charge generating agent, a hole transfer agent, an electron transfer agent and a binding resin, wherein a maximum absorption wavelength (?max) of the photo sensitive layer is set to a value of below 850 nm and an absorbance (A850) of light at a wavelength of 850 nm per unit thickness of the photo sensitive layer is set to a value of 0.05 ?m?1 or less.

Abstract: Provided are an electrophotographic photoconductor which shows a small variation in sensitivity and exhibits a high sensitivity even at a small amount of light exposure and a tandem-system color image forming device provided with the electrophotographic photoconductor. A positive charging type electrophotographic photoconductor for use in a tandem-system color image forming device including a drum type electrophotographic photoconductor, a rotation speed of which is (70) rpm or more, and a color image forming device provided with the electrophotographic photoconductor, wherein, when Vb (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 0.6 ?J/cm2 and Va (V) denotes a sensitivity in the case where an amount of light exposure per unit area is 1.5 ?J/cm2, a sensitivity ratio represented by Vb/Va is adjusted to a value of below (2).

Abstract: The present invention provides an electrophotographic photoconductive member comprising a substrate, and a photoconductive layer containing a hole transferring material, a charge generating material and a binder resin, wherein a value (IV/OV value) in which the inorganic value is divided by the organic value of the binder resin is 0.

Abstract: The present invention provides a monolayer type electrophotographic photoconductor which can effectively suppress the generation of an exposure memory and exhibits high sensitivity and an image forming apparatus using the monolayer type electrophotographic photoconductor. In an electrophotographic photoconductor which has a monolayer type photoconductive layer including at least a charge generating agent, a hole transfer agent, an electron transfer agent and a binding resin on a substrate, the charge generating agent contains oxo-titanyl phthalocyanine crystal, the electron transfer agent has a reduction potential thereof set to a value which falls within a range from ?0.97 to ?0.83 V, and the reflection absorbance (A/?) of the photoconductive layer with respect to light having a wavelength of 700 nm, a film thickness (d/m) of the photoconductive layer, and the concentration (C/weight %) of the oxo-titanyl phthalocyanine crystal of the photoconductive layer (100 weight %) satisfy a following formula (1).