An example method of determining dot gain in a liquid electrophotographic printer is described. The method involves effecting a print operation based on a predetermined digital dot area and measuring an operating current of a binary ink development unit during the print operation. A dot gain between the digital dot area and a physical dot area of a developed image is determined based on a function of the measured operating current.

In one example, a method is described that includes a processor detecting a voltage of a photoconductor layer of a printing device, comparing the voltage of the photoconductor layer to a threshold voltage, and applying a corrective voltage to a charging unit or to a transfer member when the voltage of the photoconductor layer exceeds the threshold voltage.

An image forming apparatus includes: a photoreceptor including a surface layer; a storage that stores a target value of a variation of a film thickness of the surface layer; and a hardware processor that acquires a variation of the film thickness in a first period within which the photoreceptor rotates a predetermined number of times, and sets a margin that is an amount of a portion for allowance with respect to a proper value of a parameter related to control of the photoreceptor, the margin being to be employed after the first period.

An image forming apparatus includes a photoconductor, a charging roller to charge the photoconductor, a power source to apply a charging bias to the charging roller, a current sensor to generate a feedback signal representing an output current flowing from the charging roller to the photoconductor, a memory, and circuitry. The circuitry calculates film thicknesses of a photoconductor film of the photoconductor at a plurality of points of time based on a voltage of the charging bias and the output current, calculates travel distances of the photoconductor charged at the plurality of points of time, associates the film thicknesses with the travel distances, stores the film thicknesses and the travel distances in the memory, calculates a present estimated film thickness based on the film thicknesses and the travel distances, and calculates an estimated film thickness range corresponding to a present travel distance based on the present estimated film thickness.

An image forming apparatus includes a member arranged in contact with or in proximity to an image carrier, a sensor for measuring an electrical characteristic value of the member, a power supply which switches from a first mode in which one of a constant current and a constant voltage is applied to the member to a second mode in which the other is applied to the member, a storage which stores first correspondence between an amount of use of the member in the first mode and the electrical characteristic value, and a hardware processor. The hardware processor obtains second correspondence between the electrical characteristic value measured with the sensor and the amount of use of the member in the first mode and predicts a serviceable period of the member when the power supply is switched to the second mode based on the first and the second correspondences.

An image forming apparatus includes an image bearing member, a charging roller, a toner image forming portion, a voltage source, a detecting member, a controller, and a test executing portion configured to execute an operation in a test mode in which in a period in advance of the image forming period, a plurality of test AC voltages having a test peak-to-peak voltage with different frequencies are successively applied to the charging roller and alternating currents are detected by the detecting member. The test executing portion sets a predetermined peak-to-peak voltage on the basis of a specific frequency which is a maximum frequency at which a relationship between the frequencies and the alternating currents acquired in the operation in the test mode maintains linearity.

A developing device for forming an image by developing an electrostatic latent image formed on an image carrier with a developer, includes: a developing container that accommodates the developer, a developing roller that faces the image carrier, is disposed adjacent to the developing container, and conveys the developer accommodated in the developing container to the image carrier, and a developer discharging part that is provided in the developing container and discharges a part of the developer, wherein a discharge amount of the developer discharged by the developer discharging part is controlled on the basis of a charge amount of a toner included in the developer.

An image forming apparatus includes an image transfer belt; a first transfer member; a second transfer member opposed to the first transfer member with the belt therebetween to; an applying device for applying a voltage at least one of the first and second transfer members; and a controller for controlling the applying device to apply to the at least one transfer member a voltage having the same polarity as a regular polarity of toner and a voltage of the opposite a first transfer member cleaning operation. The controller changes a number of image formations to be carried out from a cleaning operation to a next cleaning operation depending on the kind of the sheet. The number controlled by the controller is different depending on the kind of the sheets in a continuous printing job.

An image forming apparatus, includes an image processing device to perform processing, using electrical power supplied from a supply source, the supply source being selected from a commercial power supply, a first electrical power storage device, and a second electrical power storage device, the second electric power supply storage device supplying electric power in an amount smaller than an amount supplied from the first electric power supply storage device; and circuitry to control the processing to be performed by the image processing device according to the selected supply source. When the supply source is the first electrical power storage device, the circuitry controls the image processing device to execute processing that is executable when the supply source is the commercial power supply. When the supply source is the second electrical power storage device, the circuitry controls the image processing device to execute a part of the processing that is executable when the supply source is the commercial power supply.

Let V1 be a potential difference between a photosensitive member charged by a charging member to which a second charging voltage is applied in a preparation process and a developing member to which a developing voltage is applied. Let V2 be a potential difference between the photosensitive member charged by the charging member to which a first charging voltage is applied in an image forming process and the developing member. Given this definition, a relation of |V1|<|V2| is satisfied.