Image Forming Apparatus Having Photosensitive Body and Charging Device

An image forming method for an image forming apparatus, the image forming apparatus comprising:

• an image forming portion configured to form a toner image, the image forming portion comprising:
• a photosensitive body;
• a charging device configured to charge a surface of the photosensitive body;
• an exposure device configured to irradiate light on the surface of the photosensitive body;
• a toner supply device configured to supply toner to the photosensitive body;
• and a transfer device configured to transfer a toner image from the photosensitive body to transfer medium,
• the image forming method comprising:
• determining a continuously printed amount that has been attained by the image forming portion while the image forming portion has formed toner images continuously with a time interval between every two successive image-forming timings having a length shorter than or equal to a prescribed length, the image forming portion forming a toner image at each image-forming timing;
• and
• setting a charging voltage to be applied to the charging device based on a sum of a reference charging voltage and a correction value, the reference charging voltage being determined based on a target surface potential of the photosensitive body, the correction value being determined based on the continuously printed amount.

A non-transitory computer readable storage medium storing a set of program instructions for an image forming apparatus, the image forming apparatus comprising:

• an image forming portion configured to form a toner image, the image forming portion comprising:
• a photosensitive body;
• a charging device configured to charge a surface of the photosensitive body;
• an exposure device configured to irradiate light on the surface of the photosensitive body;
• a toner supply device configured to supply toner to the photosensitive body;
• and a transfer device configured to transfer a toner image from the photosensitive body to transfer medium,
• the program instructions, when executed by the image forming apparatus, causing the image forming apparatus to perform:
• determining a continuously printed amount that has been attained by the image forming portion while the image forming portion has formed toner images continuously with a time interval between every two successive image-forming timings having a length shorter than or equal to a prescribed length, the image forming portion forming a toner image at each image-forming timing;
• and
• setting a charging voltage to be applied to the charging device based on a sum of a reference charging voltage and a correction value, the reference charging voltage being determined based on a target surface potential of the photosensitive body, the correction value being determined based on the continuously printed amount.