An image forming apparatus includes: an image bearing member; a developer carrying member to correspond to the image bearing member; drive portion to rotationally drive the developer carrying member; control unit to control the rotational drive by the drive portion, and detection portion to detect information from the toner patch. Modes for controlling, by control unit, the rotational drive of the drive portion include (i) a first mode which uses a first driving condition including a first peripheral speed ratio between the developer carrying member and the image bearing member and (ii) a second mode which uses a second driving condition including a second peripheral speed ratio which is higher than the first peripheral speed ratio. The control unit controls the image bearing member to form the toner patch for each of peripheral speed ratios and sets the second driving condition on the basis of the detected information.

An image forming apparatus including an image forming unit, a fixing device, and circuitry is provided. The image forming unit is configured to perform a special image forming operation that forms a color toner image and a special toner image with a color toner and a special toner, respectively, on a recording medium and a normal image forming operation that forms the color toner image without forming the special toner image on the recording medium. The fixing device is configured to fix the color toner image and the special toner image on the recording medium. The circuitry is configured to perform, in the special image forming operation, a toner amount suppression control that makes an amount of the color toner on the recording medium per unit area smaller than that in the normal image forming operation.

An image forming apparatus includes: an image carrier in which a latent image is formed; a developing device that transfers toner to the latent image from a developing member opposed to the image carrier, and develops the latent image; a development power supply that applies a development voltage across the image carrier and the developing member; a period detector that detects periodic information on the developing member and the image carrier in a circumferential direction; and a corrector that corrects the development voltage or an exposure amount of the latent image based on the periodic information detected by the period detector. At least one of the developing device and the development power supply is set so that a supply rate of charge of the toner to the latent image in a solid area of an image reaches 80% or higher.

An image inspection system including: an image forming apparatus that forms an image on a sheet; an image reading apparatus that reads the image formed on the sheet through the image forming apparatus; and an image inspector that inspects the image read by the image reading apparatus. The image inspector includes a hardware processor that sets an edge portion of the sheet as an image inspection excluded area that is excluded from targets for inspection of the image.

An image forming apparatus includes: an image former that forms an image, which is desired by a user and different from a predetermined pattern, on a sheet; an output information detector that detects output information on a first image formed on a first sheet by the image former; and a hardware processor that: acquires an correction amount of a third image, which is formed on a third sheet after the first sheet and a second sheet, according to a detection result of the first image by the output information detector and image information on a second image formed on the second sheet after the first sheet by the image former; and controls the image former so as to correct the third image based on the correction amount acquired by the hardware processor.

An image foil ling apparatus includes a latent image bearer, a charger, an exposure device, a developing device, a toner adhesion amount detector, and control circuitry. The control circuitry controls the charger, the exposure device, and the developing device to form a detection toner pattern shorter than a circumferential length of the latent image bearer in a circumferential direction of the latent image bearer at an area of the latent image bearer including at least a part of an opposite portion of the latent image bearer opposite the charger when the latent image bearer stops rotation, controls the toner adhesion amount detector to detect a toner adhesion amount of the detection toner pattern, and executes a refreshing operation to recover the surface of the latent image bearer from a deteriorated state due to a discharge product based on a result of the detection toner pattern detected by the toner adhesion amount detector.

A method of stabilizing a marking process speed in a printing system, the printing system including a vacuum transport belt and at least one sheet onto which marking material is directly applied to print sheets, the method including printing an image on the sheet, receiving, from a sensor, data related to the image, determining, based on the data, at least one actual dimension of the image, determining if the at least one actual dimension of the image is equal to a target dimension of the image, and if the at least one actual dimension is not equal to the target dimension, adjusting one or more components of the printing system.

An image forming apparatus includes: an image former that divides a first image into a plurality of second images and forms the second images on an image carrier; a test image reader that reads the second images formed on the image carrier; and a hardware processor that: selects a number of the second images from among the second images read by the test image reader, the number of the second images being smaller than a number of division of the first image; combines the selected second images into a combined image; and detects an image defect in the combined image.

A measurement apparatus includes a sheet stacking portion provided above a first conveyance path and on which a second sheet discharged out of a second conveyance path is stacked. The sheet stacking portion includes an extension tray configured to support the sheet discharged out of the second conveyance path and to be movable between a first position and a second position, the first position being a position where the extension tray is located inside a width of the measurement apparatus in the horizontal direction, and the second position being a position where the extension tray is located above an upstream apparatus and is overlapped with the upstream apparatus when viewed in a gravity direction.

An image forming apparatus includes a storage unit and a charging amount acquisition unit. The charging amount acquisition unit performs a charging amount acquisition operation for forming a measurement toner image on the image carrier while changing the frequency of the alternating current voltage of the development bias with a potential difference in a direct current voltage between the developing roller and the image carrier being kept constant, acquiring a tilt of a measurement straight line representing a relationship between the change amount of the frequency and a density change amount of the measurement toner image, and acquiring the charging amount of the toner based on the acquired tilt of the measurement straight line and the reference information in the storage unit.