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.

A developing device, including: a developer containing toner and carrier; and developer bearer configured to have surface thereof bear the developer and endlessly move, and to develop latent image over surface of latent image bearer by supplying toner in developer to latent image in developing region facing the latent image bearer, wherein carrier contains fine particles, value X in volume resistivity R (=10.sup.X) (?.Math.cm) of carrier is 11.5-16.0, developer bearer includes: magnetic field generating unit including a plurality of magnetic poles; and developing sleeve having a cylindrical shape enclosing magnetic field generating unit, and configured to bear developer over outer circumferential surface of cylindrical shape by magnetic force of the magnetic field generating unit and perform surface moving by rotating relative to developing device body, and developing device includes developing sleeve voltage applying unit configured to apply AC component-containing voltage to developing sleeve.

An image forming device includes a communication device, an image forming unit, a transfer unit, a transmitting unit, and a processor. The communication device communicates includes a wireless tag. The image forming unit forms a developer image on a surface of a photoreceptor. The transfer unit transfers the developer image to a medium provided with the wireless tag communicating with the communication device. The transmitting unit transmits the medium to the transfer unit. The processor controls an operation of the transmitting unit so as to transmit the medium at a first timing when communication with the wireless tag by the communication device is normally executed and controls the operation of the transmitting unit so as to transmit the medium at a second timing different from the first timing when the communication with the wireless tag by the communication device is not normally ended.

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 an image forming portion, an adjustment processing portion, an acquisition processing portion, and a setting processing portion. The image forming portion forms an image using toner. During execution of an image forming process using the image forming portion, the adjustment processing portion uses the toner to adjust the image quality of an output image output by the image forming process. The acquisition processing portion acquires variation amount information related to the amount of variation in a predetermined state value related to the image forming portion caused by a start of the image forming process. The setting processing portion sets the frequency of adjustment of the image quality of the output image by the adjustment processing portion, based on the variation amount information acquired by the acquisition processing portion.

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.

According to an aspect of the invention, a developing device includes a developer holding member that holds developer including toner which is charged to have a predetermined polarity on a surface and performs development of an electrostatic latent image with respect to an image holding member which holds the electrostatic latent image while being rotated; a storage member that stores the developer therein and has an opening portion for discharging air in which flow is generated by the rotation of the developer holding member; and a collection member that is provided in the opening portion of the storage member to be charged to the predetermined polarity, causes air to pass therethrough, and collects toner.

An image forming apparatus includes a developing device including a developing roller, a supply roller, and a conductive roller. During image formation, a bias is applied to each of the supplying roller, the developing roller, and the conductive roller in a state in which each of the supplying roller, the developing roller, and the conductive roller is rotationally driven. During the image formation, a polarity of a first potential obtained by subtracting a DC potential of the developing roller from a DC potential of the supplying roller is the same as a normal charge polarity of the toner, and a polarity of a second potential obtained by subtracting the DC potential of the developing roller from a DC potential of the conductive roller is the same as the normal charge polarity of the toner.

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.