Image forming apparatus and image forming method

An image forming apparatus comprising:

• an image bearing member;
• a charger configured to charge a circumferential surface of the image bearing member;
• a static elimination device configured to eliminate static electricity from the circumferential surface of the image bearing member;
• and
• a cleaning member pressed against the circumferential surface of the image bearing member and configured to collect a toner remaining on the circumferential surface of the image bearing member, wherein
• the toner has a number average roundness of at least 0.965 and no greater than 0.998,
• the toner has a volume median diameter of at least 4.0 μm and no greater than 7.0 μm,
• a linear pressure of the cleaning member on the circumferential surface of the image bearing member is at least 10 N/m and no greater than 40 N/m,
• the static elimination device emits a static elimination light having an intensity of greater than 0 μJ/cm2 and no greater than 5 μJ/cm2 upon arrival at the circumferential surface of the image bearing member,
• the charger charges the circumferential surface of the image bearing member after at least 50 milliseconds from static elimination of the circumferential surface of the image bearing member by the static elimination device,
• the image bearing member includes a conductive substrate and a single-layer photosensitive layer,
• the single-layer photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin, and
• ionization potential IpHTM of the hole transport material and ionization potential IpCGM of the charge generating material satisfy mathematical formulae (1), (2), and (3)
• IpHTM≥5.30 eV (1)
• IpCGM≥5.30 eV (2)
• 0.09 eV≤|IpHTM−IpCGM|≤0.30 eV. (3).