In an image forming apparatus, in a case in which a second toner image to be transferred to a same recording material as a first toner image is to be transferred is formed on the photosensitive member after the first toner image is formed on the photosensitive member and the first toner image is formed on an area of the photosensitive member including at least a part of a position of the second toner image one cycle before with respect to a movement direction of the surface of the photosensitive member, a control unit changes a value of a transfer current at a time of transferring the first toner image to a transfer-receiving member between a first value and a second value of which an absolute value is greater than an absolute value of the first value, based on image information regarding the second toner image.

An image forming apparatus includes an image forming portion, a high-voltage generation circuit, a current detection portion and a control portion. The image forming portion includes an image carrying member, a charging device, an exposure device and a developing device which includes a developer carrying member for carrying a developer including a carrier and a toner. The control portion can perform a development ghost prediction mode that includes a step of measuring the amount of charge of the toner within the developing device at the time of non-image formation, a step of measuring, as a carrier current, the direct-current component of a development current when the amount of development of the toner is 0 [mg/cm.sup.2] and a step of estimating the level of occurrence of development ghost and the cause of occurrence based on the amount of charge of the toner and the carrier current which are measured.

An image forming apparatus includes a developing unit, a transfer unit, a power source unit configured to supply a developing bias voltage to the developing unit and a transfer bias voltage to the transfer unit, and an input device to receive an image density evaluation. A processor performs adjusts the developing bias voltage when an evaluation input indicating a defect in the image density is received. If, after the first adjustment, another evaluation input indicating a defect in image density is received, the processor adjusts one of the developing bias voltage, the transfer bias voltage, or the toner density in the developing unit.

An image forming apparatus includes a developing unit, a transfer unit, a power source unit configured to supply a developing bias voltage to the developing unit and a transfer bias voltage to the transfer unit, and an input device to receive an image density evaluation. A processor adjusts the developing bias voltage when an evaluation input indicating a defect in the image density is received. If, after the first adjustment, another evaluation input indicating a defect in image density is received, the processor adjusts one of the developing bias voltage, the transfer bias voltage, or the toner density in the developing unit.

An image forming apparatus includes a developer, a development device, and an image bearing member. The developer includes an initial developer containing an initial carrier and a replenishment developer containing a replenishment carrier. The initial carrier has a surface roughness Sa1 of at least 0.3 ?m and no greater than 1.0 ?m. A ratio Sa1/Sa2 of the surface roughness Sa1 of the initial carrier to a surface roughness Sa2 of the replenishment carrier is at least 1.2 and no greater than 3.4. The packing volume Vp calculated from equation (1)Vp=100?Y/(Z?DS) was at least 40% and no greater than 70%. In equation (1), Y represents an amount of the developer conveyed by a developer bearing member. Z represents an apparent density of the initial developer. DS represents a width of a space between the developer bearing member and the image bearing member.

An image forming apparatus includes a movable photosensitive member, a charging roller, an electrostatic image forming portion, a developing sleeve, a charging voltage source, a charging voltage conducting path, a developing voltage source, a developing voltage conducting path, and a capacitor electrically connected between an output terminal of the charging voltage source and a ground potential or between the charging voltage conducting path and the ground potential. The capacitor satisfies the following relationship: {C1/(C1+C2)}Vpp5 (V), where C1 (pF) is electrostatic capacity formed by the first and second conducting paths, C2 (pF) is electrostatic capacity of the capacitor, and Vpp (V) is a peak-to-peak voltage of the AC component of the developing voltage.

An image forming apparatus includes a rotatable image bearing member, a developing device including a developing carrying member and configured to develop an electrostatic image formed on the image bearing member with developer, an electrostatic capacity detecting portion configured to detect information on electrostatic capacity between the developer carrying member and the image bearing member, and a toner content detecting portion configured to detect information on a toner content of the developer accommodated in a developing container. On the basis of the detected electrostatic capacity and the detected toner content, a controller controls a driving speed at which the developer carrying member is rotationally driven.

An electrophotographic image forming apparatus includes a latent image bearer to rotate and bear a latent image, a charging device to charge the a latent image bearer, a developing device to develop the latent image with developer including toner and use a developing voltage including an AC component, and a lubricant applicator to apply lubricant onto a surface of the latent image bearer. An amount of the lubricant applied by the lubricant applicator onto the latent image bearer per centimeter in an axial direction of the latent image bearer is equal to or greater than 0.845 mg for a running distance of 1.0 kilometer of the latent image bearer, and a difference between a largest value and a smallest value of the developing voltage is in a range of 200 V to 400 V.

A development device includes a magnetic field generation unit having a developing magnetic pole S2, a magnetic pole N2, and a magnetic pole N1. The magnetic poles N2 and N1 are disposed adjacent to the magnetic pole S2, at positions downstream and upstream of the magnetic pole S2 in a rotation direction of a sleeve, respectively. The magnetic pole N2 is configured to have a larger magnetic flux density and full width half maximum in a normal direction of the sleeve and have a smaller inter-pole distance from the developing magnetic pole than the magnetic pole N1, so that the rising position of magnetic brushes of developer is shifted in the upstream direction, and the magnetic brushes come into contact with a photosensitive drum more suitably.

An image forming apparatus includes: an image carrier that rotates while carrying a toner image; an image former that forms the toner image; a transfer roller that transfers the toner image to a recording medium; and a bias voltage applier that applies a voltage to the transfer roller, wherein the image former forms transfer images and forms a patch image with toner between a first transfer image and a second transfer image, and the bias voltage applier applies a first voltage having a polarity opposite to a charge polarity of the toner to the transfer roller, applies a second voltage having the polarity opposite to the charge polarity of the toner and larger than the first voltage to the transfer roller, and applies a third voltage having the polarity opposite to the charge polarity of the toner and smaller than the second voltage to the transfer roller.