Electrophotographic photoconductor, and image forming apparatus, process cartridge and image forming method using the same

An image forming apparatus, comprising:

• at least an electrophotographic photoconductor;
• a charging unit configured to charge the photoconductor;
• an exposing unit configured to expose the charged photoconductor to form a latent electrostatic image;
• a developing unit configured to develop the latent electrostatic image by using a toner;
• a transfer unit configured to transfer the visible image developed by the toner to a recording medium,
• wherein the electrophotographic photoconductor comprises:
• a support;
• and
• at least a photosensitive layer disposed on the support,
• wherein the photosensitive layer comprises at least a charge generating material and a charge transporting material expressed by the following Structural Formula (1-1), and
• wherein, in the Structural Formula (1-1), R1 and R2 may be identical to each other or different, and represent any one of hydrogen atom, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted;
• R3, R4, R5, R6, R7, R8, R9, and R10 may be identical to each other or different, and represent any one of hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted;
• wherein the electrophotographic photoconductor comprises a bipolar optical sensitivity of positive and negative, and a ratio of optical sensitivity at each polarity, E½ (positive) and E½ (negative), [E½ (negative)/E½ (positive)], where “E½” is an exposure energy (μJ/cm2) required for a surface potential to be ½ by exposing with a single light after the electrophotographic photoconductor is charged at ±800V, is 0.5 to 3.0.

A process cartridge, comprising:

• at least an electrophotographic photoconductor;
• and
• a developing unit configured to develop a latent electrostatic image formed on the electrophotographic photoconductor by using a toner to form a visible image,
• wherein the process cartridge can be attached to and removed from an image forming apparatus body,
• the process cartridge comprises a bipolar optical sensitivity of positive and negative, and a ratio of optical sensitivity at each polarity, E½ (positive) and E½ (negative), [E½ (negative)/E½ (positive)], where “E½” is an exposure energy (μJ/cm2) required for a surface potential to be ½ by exposing with a single light after the electrophotographic photoconductor is charged at ±800V, is 0.5 to 3.0, and
• wherein the electrophotographic photoconductor comprises:
• a support;
• and
• at least a photosensitive layer disposed on the support,
• wherein the photosensitive layer comprises at least a charge generating material and a charge transporting material expressed by the following Structural Formula (1-1), and
• wherein, in the Structural Formula (1-1), R1 and R2 may be identical to each other or different, and represent any one of hydrogen atom, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted;
• R3, R4, R5, R6, R7, R8, R9, and R10 may be identical to each other or different, and represent any one of hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted.

An image forming apparatus, comprising:

• at least an electrophotographic photoconductor;
• a charging unit configured to charge the photoconductor;
• an exposing unit configured to expose the charged photoconductor to form a latent electrostatic image;
• a developing unit configured to develop the latent electrostatic image by using a toner;
• a transfer unit configured to transfer the visible image developed by the toner to a recording medium;
• and
• a cleaning unit configured to remove the residual toner on the photoconductor,
• wherein the electrophotographic photoconductor comprises:
• a support;
• and
• at least a photosensitive layer disposed on the support,
• wherein the photosensitive layer comprises a charge generating material and a charge transporting material expressed by the following Structural Formula (1-1), and
• wherein, in the Structural Formula (1-1), R1 and R2 may be identical to each other or different, and represent any one of hydrogen atom, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted;
• R3, R4, R5, R6, R7, R8, R9, and R10 may be identical to each other or different, and represent any one of hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted.

A process cartridge, comprising:

• at least an electrophotographic photoconductor;
• a developing unit configured to develop a latent electrostatic image formed on the electrophotographic photoconductor by using a toner to form a visible image;
• and
• a cleaning unit,
• wherein the process cartridge can be attached to and removed from an image forming apparatus body,
• the electrophotographic photoconductor comprises a support and at least a photosensitive layer on the support,
• the photosensitive layer comprises a charge generating material and a charge transporting material expressed by the following Structural Formula (1-1), and
• wherein, in the Structural Formula (1-1), R1 and R2 may be identical to each other or different, and represent any one of hydrogen atom, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted;
• R3, R4, R5, R6, R7, R8, R9, and R10 may be identical to each other or different, and represent any one of hydrogen atom, halogen atom, cyano group, nitro group, amino group, hydroxyl group, alkyl group which may be substituted, cycloalkyl group which may be substituted and aralkyl group which may be substituted.