An image forming apparatus includes a cassette to store a recording medium, an image forming unit to form an image on an image bearing member based on an image forming condition, a transfer unit to transfer the image onto the recording medium conveyed from the cassette, and a reading unit to read a test image formed on the recording medium by the image forming unit. A controller controls the image forming unit to form the test image while the image forming unit is forming a plurality of images, controls the image forming condition based on a reading result of the test image by the reading unit, and obtains information related to basis weight of the recording medium in the cassette. In a case where the information does not satisfy a forming condition for forming the test image, the test image is not formed.

An image forming apparatus according to this disclosure includes: a charging roller that charges a surface of a photoconductor drum; a development unit that forms a toner image on the surface of the photoconductor drum; an image density sensor that detects density of the formed toner image; a charge power supply that applies a bias voltage to the charging roller; a development power supply that applies a bias voltage to the development unit; and a controller. The controller causes the charge and development power supplies to output respective predetermined bias voltages for predetermined time, and is capable of executing a contact and separation determination mode in which a contact and separation state of the charging roller is determined based on whether or not an image is detected by the image density sensor after output of the respective bias voltages.

A developing device includes a hardware processor that performs control not to cause an image to be formed on an image bearing member by a first developer bearing member and to cause a first image to be formed on the image beating member by a second developer bearing member, in which the hardware processor corrects developing conditions of the plural developer bearing members based on a developability detection result of the first image formed by the second developer bearing member.

An image forming apparatus includes: an image carrier that carries and transports a latent image; a charging member that is arranged to be in contact with a surface of the image carrier; a developing device that supplies toner to the image carrier and forms a toner image; a density detection unit that detects a density of the toner image; a pattern detection unit that detects a predetermined density variation pattern based on a detection result of the density detection unit according to the toner image; and a determination unit that determines a state of the charging member based on the number of the predetermined density variation patterns detected within a predetermined period of time.

An image forming unit forms a toner image on an image carrier using toner. A transfer unit transfers the toner image to a sheet. A cleaner removes, from the image carrier, residual toner that was not transferred to the sheet by the transfer unit. In a detection mode for detecting a part of the image forming apparatus causing a streak, a controller may control the image forming unit to form a pattern on the image carrier, control the transfer unit so that the pattern passes through a transfer position without transferring the pattern to the sheet, control the cleaner to remove the pattern on the image carrier, and control the transfer unit to transfer a residual streak from the image carrier to the sheet. The residual streak occurs from the pattern image by causing an error of the cleaner.

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.

An image forming apparatus includes an image former; a detector; and a hardware processor that: calculates a minimum area for each of the plurality of tones based on image data of the image, calculates a density ratio between the densities before and after the transferring is made for each of the plurality of tones from the densities detected by the detector, extracts as a first area a minimum area of a tone corresponding to a density ratio which switches from less than a predetermined threshold to equal to or more than the threshold, and extracts as a second area a minimum area of a tone the density ratio of which is a maximum, and changes a setting of a dot size of the image so that a size of the second area becomes the same as a size of the first area until the next setting change is performed.

An image forming apparatus includes a memory and circuitry. The memory is configured to store a status of the image forming apparatus and a first detected density value obtained in a first tone correction based on a dither pattern. The circuitry is configured to calculate a difference between the status of the image forming apparatus upon the first tone correction and the status of the image forming apparatus upon a second tone correction following the first tone correction. The circuitry is further configured to calculate a correction value according to the difference in the status of the image forming apparatus, based on the first detected density value and a second detected density value obtained in the second tone correction based on a reference pattern.

An image forming apparatus includes an intermediary transfer member; a first image forming portion including a first developing device and a detecting portion; a second image forming portion including a second developing device; a contact-and-separation mechanism capable of setting a first state and a second state; and an executing portion capable of executing an operation in a first monochromatic mode in the first state and capable of executing an operation in a second monochromatic mode in the second state. When a toner amount in the first developing device is below a predetermined amount on the basis of the detecting portion during an image forming operation for continuously forming the black image in the operation in the first monochromatic mode, the executing portion continuously executes the image forming operation in the second state.

An image forming apparatus includes an image forming unit and a controller. The image forming unit includes a latent image bearer, a charger to charge the latent image bearer, an exposure device to expose a latent image on the surface of the latent image bearer, and a developing device to develop the latent image with a developer. The controller executes an image forming process, a first fluctuation control that cyclically changes a developing bias supplied to the developing device based on predetermined first pattern data, and a second fluctuation control that cyclically changes a charging bias supplied to the charger based on predetermined second pattern data, in parallel. The controller executes a determination process to determine whether the controller executes the first fluctuation control. When the controller determines not to execute the first fluctuation control, the controller determines not to execute the second fluctuation control, too.