An image forming apparatus includes an image forming portion configured to form a toner image. The image forming portion includes: a photosensitive body; a charging device; an exposure device; a toner supply device; and a transfer device. A continuously printed amount, which 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, is determined. A charging voltage to be applied to the charging device is set 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 relationship between a light amount of an exposure portion and a surface potential according to a use amount, a first detection light amount corresponding to a prescribed surface potential in the relationship where a use amount of a photosensitive member is a first use amount and a second detection light amount corresponding to the prescribed surface potential in the relationship where the use amount of the photosensitive member is a second use amount, which is greater than the first use amount, are acquired. The exposure portion changes, as an electrostatic image forming light amount, a first image forming light amount representing a setting value under the first use amount to a second image forming light amount representing a setting value under the second use amount on the basis of a ratio of the first detection light amount to the second detection light amount.

The image bearing member includes an image bearing member, a charge unit that charges the image bearing member, an exposure unit that exposes the image bearing member by emitting light thereto, a transfer unit that transfers an image formed on the image bearing member, a detection unit that detects a current flowing between the transfer unit and the image bearing member when a voltage is applied to the transfer unit, and a control unit that causes the charge unit to charge the image bearing member through application of a DC voltage, and calculates a surface potential of the image bearing member based on a detection result of the current when the voltage is applied to the transfer unit, after a light whose light amount is higher than a light amount of a light emitted to the image bearing member from the exposure unit is emitted to the image bearing member.

An image forming apparatus includes a photosensitive member, a charging member, a charging voltage source, an exposure device, a developing device, a developing voltage source, a transfer member, a transfer voltage source, a detecting member, a setting portion for setting, a transfer voltage applied to the transfer member on the basis of a detection result of the detecting member, and an adjusting portion for increasing a potential difference between the potential of the photosensitive member charged and the developing voltage so as to be large when an absolute value of the transfer voltage set by the setting portion is a first threshold or more and an absolute value of the current flowing at the time of application of the transfer voltage to the transfer member is a second threshold or less.

An image forming apparatus includes: a photosensitive member; a charging unit configured to charge the photosensitive member; an exposure unit configured to expose the photosensitive member charged by the charging unit with a laser beam in order to form an electrostatic latent image; a development unit configured to develop the electrostatic latent image on the photosensitive member to form an image; an obtaining unit configured to obtain information related to the photosensitive member; a measuring unit configured to measure a measurement image formed by the charging unit, the exposure unit, and the development unit; and a determination unit configured to determine an image forming condition for adjusting a maximum density of the image to be formed, based on a measurement result of the measuring unit and the information obtained by the obtaining unit.

An image forming apparatus includes: a power source applying voltage to a charging roller to charge a photosensitive drum; a toner-image forming unit forming a toner image on the photosensitive drum; a detecting member which detects a DC current to be flowed from the charging roller to the photosensitive drum; a driving source driving the photosensitive drum at a predetermined speed; and an execution unit executing a detection mode to detect the DC current with the detecting member when the voltage is applied in a state in which the photosensitive drum is rotated, in a period except a period during which the toner image is formed on the photosensitive drum, the execution unit setting a speed of the driving source when the detection mode is executed at a second speed faster than a first speed that is fastest in the period during which the toner image is formed.

Presented is an image forming apparatus that includes a plurality of photoconductors, a sensor, a first memory, and a processor. The photoconductors include first and second photoconductors on which a toner image is formed in response to an image being formed. The sensor detects a physical amount that changes in response to a deterioration state of the first photoconductor. The first memory collects and stores a history of the physical amount and usage status information relating to a usage status of the first photoconductor. The processor performs a prediction of a lifespan of the second photoconductor and determination of a failure of the second photoconductor based on the history of the physical amount and the usage status information of the first photoconductor, and usage status information relating to a usage status of the second photoconductor.

An image forming apparatus is provided that includes a light-emitting unit which emits light to an image bearing member which bears a developer image and that detects presence or absence of a developer container storing developer or a shape of the developer container on the basis of the number of electrons discharged from or received by the image bearing member when the light-emitting unit emits the light.

A relationship between a light amount of an exposure portion and a surface potential according to a use amount, a first detection light amount corresponding to a prescribed surface potential in the relationship where a use amount of a photosensitive member is a first use amount and a second detection light amount corresponding to the prescribed surface potential in the relationship where the use amount of the photosensitive member is a second use amount, which is greater than the first use amount, are acquired. The exposure portion changes, as an electrostatic image forming light amount, a first image forming light amount representing a setting value under the first use amount to a second image forming light amount representing a setting value under the second use amount on the basis of a ratio of the first detection light amount to the second detection light amount.

An image forming apparatus includes: a power source applying voltage to a charging roller to charge a photosensitive drum; a toner-image forming unit forming a toner image on the photosensitive drum; a detecting member which detects a DC current to be flowed from the charging roller to the photosensitive drum; a driving source driving the photosensitive drum at a predetermined speed; and an execution unit executing a detection mode to detect the DC current with the detecting member when the voltage is applied in a state in which the photosensitive drum is rotated, in a period except a period during which the toner image is formed on the photosensitive drum, the execution unit setting a speed of the driving source when the detection mode is executed at a second speed faster than a first speed that is fastest in the period during which the toner image is formed.