An image forming apparatus includes a photoconductor, a charger, a detection unit, and a determination unit. The charger charges the photoconductor. The detection unit detects an actual charging potential of the photoconductor after the photoconductor is charged by the charger. The determination unit determines one of a plurality of causes related to a charging abnormality of the photoconductor based on a relationship between a standard charging potential of the photoconductor to be obtained by charging by the charger and a charging potential detected by the detection unit.

An image forming apparatus includes: an image holder configured to hold an image formed using an electrographic process; a transfer body that faces the image holder and is configured to contact the image holder while rotating to form a secondary transfer region; an application unit configured to apply a voltage for charging the secondary transfer region; and a charge unit that faces a region other than the secondary transfer region of the transfer body and is configured to charge a surface of the transfer body with a polarity opposite to an applied voltage of the application unit.

An image forming apparatus includes: a development device which develops an electrostatic latent image formed on a photosensitive drum into a toner image; a charger which charges the photosensitive drum; a development power supply which applies a prescribed bias voltage to the development device; and a calculating section which calculates a surface potential of the photosensitive drum based on a development current flowing in the development device. The calculating section calculates, as the surface potential, a bias voltage at which a non-charging development current that flows in the development device in an uncharged state in which the charger has not charged the photosensitive drum is equal to a charging development current that flows in the development device in a charged state in which the charger has charged the photosensitive drum.

An image forming apparatus provided with a conductive member to form an image on a sheet using a toner includes: a voltage acquisition portion configured to acquire a biased voltage value as a voltage value by applying a bias to the conductive member; an environment sensor configured to output an environment condition measurement value representing an internal environment condition; and a hardware processor configured to transform the biased voltage value acquired by the voltage acquisition portion into a virtual voltage value appearing in the conductive member as the biased voltage value under a standard environment condition, in which the environment condition has a predetermined standard condition, on the basis of the environment condition measurement value output from the environment sensor, and determine a service life of the conductive member on the basis of the virtual voltage value.

Provided is an image formation device including a photoreceptor configured to carry a toner image and a developer configured to form the toner image on a surface of the photoreceptor and configured such that the developer is a replaceable development unit, the image formation device including: a development bias application section configured to apply a development bias to between the photoreceptor and the developer; a stabilization control section configured to perform image stabilization control of determining a development bias value to be used in future by changing the development bias while measuring a density of the toner image formed by the developer, thereby obtaining the toner image with a target density; and a life determination section configured to determine expiration of use of the development unit when the development bias value determined by the stabilization control falls outside a preset acceptable range.

A control portion executes: a step of calculating a surface potential of an image bearing member charged by a charging member, to which a predetermined voltage is applied, and exposed to light by a predetermined exposure amount on the basis of a discharge start voltage between a measurement member and the image bearing member and calculating a correction value from a difference between a target value and calculated surface potential of the image bearing member; a step of correcting calculated surface potential of the image bearing member on the basis of the correction value; and a step of controlling at least one of the voltage applied to the charging member and an exposure amount of the exposure apparatus on the basis of the corrected surface potential of the image bearing member so that the surface potential of the image bearing member reaches the target value.

An image-forming apparatus includes a rotatable developer-bearing member to bear a developer composed of a toner particle and a transfer promoting particle attached to the toner particle. When F denotes pressing force for pressing the developer-bearing member against an image-bearing member, and N denotes a total number of the transfer promoting particles interposed between the toner particle and the image-bearing member, adhesion strength Ft between the transfer promoting particle and the toner particle measured by pressing the transfer promoting particle against the toner particle at a pressing force per unit transfer promoting particle F/N and adhesion strength Fdr between the transfer promoting particle and the image-bearing member measured by pressing the transfer promoting particle against the image-bearing member at the pressing force per unit transfer promoting particle F/N, satisfy Ft<Fdr. Electrical discharge is generated upstream of a transfer portion in a movement direction of an intermediate transfer belt.

An image forming apparatus comprising: an image forming unit configured to convey a recording medium, and form an image on the recording medium based on an image forming condition; and a controller configured to control the image forming unit to form a test image and a scale image extending a conveyance direction in which the recording medium is conveyed, obtain user instruction information related to a density fluctuation of the test image in the conveyance direction, and to generate the image forming condition to suppresses image density unevenness in the conveyance direction to an image to be formed by the image forming unit based on the user instruction information.

An image forming apparatus includes a photosensitive member, a charging member, an electrostatic image forming portion, a developing member, a transfer member, a transfer voltage source, a brush member, a brush voltage source, and a controller capable of executing a cleaning operation. The controller carries out control so that the cleaning operation includes a first operation in which a potential difference is formed between the transfer member and the photosensitive member so that toner charged to a normal charge polarity is moved from the transfer member toward the photosensitive member, and a second operation in which a potential difference is formed between the brush member and the photosensitive member so that the toner charged to the normal charge polarity is moved from the photosensitive member toward the brush member.

A power supply apparatus generates an output voltage. A boost circuit boosts a voltage supplied from a reference voltage source and generates a first power supply voltage. A processor controls switching the boost circuit on and off. A first transistor is connected to the first power supply voltage. A second transistor is connected to a collector of the first transistor. A resistance element is connected to a collector of the second transistor. A voltage source is connected to the resistance element and generates a second power supply voltage. A collector voltage, which is an output voltage, of the second transistor is controlled by controlling an amount of base current of the first transistor.