An image reading device includes a reader, a first background part, a second background part, and circuitry. The reader reads a pattern formed on a medium. The first and second background parts are disposed opposite the reader via a conveyance passage of the medium. The second background part has a higher light reflectance than that of the first background part. The circuitry moves one of the first and second background parts to a facing position at which the one faces the reader via the conveyance passage of the medium. The circuitry moves the first background part to the facing position in a case in which the pattern is a light color and the medium is transparent. The circuitry moves the second background part to the facing position in a case in which the pattern is a dark color darker than the light color or the medium is not transparent.

An image forming apparatus includes an image forming device forming an image, a transfer belt having an image bearing surface on which the image moves to first and second regions, a sensor installed at an installation angle to the image bearing surface and including a light emitting element emitting light, a first and second light receiving elements receiving light reflected from the first and second regions, respectively, circuitry to generate first and second information according to light entered the first and second light receiving elements, respectively, generate, when the image moves, time information according to a difference between first and second times at each of which the first and second information, respectively, reach a threshold, obtain a tilt table based on the time difference information, and determine, by the tilt table, tilt information corresponding to the time information and indicating a difference between the installation angle and a reference angle.

Provided is a printing apparatus including a cassette configured to be capable of managing a stored paper-sheet by using paper-sheet size information and paper-sheet attribute data, in which an adjustment value of a print position is registered to copied paper-sheet attribute data if an event in which the adjustment value is registered to paper-sheet attribute data in which the paper-sheet size information is not set occurs.

An image forming apparatus comprising: an image forming unit configured to form an image on a recording medium based on an image forming condition, an image reader configured to read an image for adjustment of the image forming condition, which is formed on the recording medium; and a controller configured to: control the image forming unit to form images for adjustment; control the image reader to read the images for adjustment; determine a target data based on a reading result of a first image included in reading results of the images for adjustment; and adjust the image forming condition, during execution of a job in which the image forming unit forms a plurality of images on a plurality of recording mediums, based on the target data and a reading result of second image included in the reading results of the images for adjustment.

An image forming apparatus includes an image forming device forming an image, a transfer belt having an image bearing surface on which the image moves to first and second regions, a sensor installed at an installation angle to the image bearing surface and including a light emitting element emitting light, a first and second light receiving elements receiving light reflected from the first and second regions, respectively, circuitry to generate first and second information according to light entered the first and second light receiving elements, respectively, generate, when the image moves, time information according to a difference between first and second times at each of which the first and second information, respectively, reach a threshold, obtain a tilt table based on the time difference information, and determine, by the tilt table, tilt information corresponding to the time information and indicating a difference between the installation angle and a reference angle.

An image forming apparatus includes: a job acquirer that acquires a print job; a photoconductor including a surface on which a toner image is to be formed; an electrifying member that electrifies the photoconductor; an exposure member that exposes the photoconductor; a developing member that supplies toner to the photoconductor; a cleaner that cleans the photoconductor; and a controller connected to the job acquirer to control the image forming apparatus, wherein the controller computes a first non-toner region that is provided on the surface of the photoconductor when the toner image is formed on the photoconductor, the first non-toner region not containing toner in a longitudinal direction of the surface of the photoconductor, and the controller causes the exposure member and the developing member to form the toner image on the photoconductor and to form a set of toner patches in the first non-toner region.

An image forming apparatus includes an image forming device, a first transfer device including a first mover, a second transfer device including a second mover, a transfer-pressure changer, a detector, and circuitry. The detector detects a toner image and outputs a detection value indicating an amount of toner of the toner image adhering to the second mover. The circuitry calculates a variable value for the amount of toner varying with a change in a transfer pressure, based on the detection value and a target value of the amount of toner of the toner image to be transferred and adhere to the second mover, reflects the calculated variable value in the detection value to correct the detection value, adjusts an image-forming condition based on the corrected detection value, and sets the image-forming condition of the toner image in the image forming device based on the corrected detection value.

An image reading device includes an image reader and circuitry. The image reader is configured to read an image on a recording medium. The circuitry is configured to obtain defective image information and defect type information based on the image on the recording medium read by the image reader, and determine an abnormality of the image on the recording medium based on the defective image information and the defect type information.

An image forming apparatus includes: an image forming portion having an image carrying member, a charging device, an exposing device, and a developing device; a developing voltage power supply; a control portion; and an image density sensor. The developing device has a developer carrying member that carries two-component developer and a toner concentration sensor. The control portion senses toner concentration during calibration or during first image formation after calibration for correcting image density based on the sensing result from the image density sensor. If the difference VtargetV between the output value V of the toner concentration sensor actually sensed and a target value Vtarget of the toner concentration sensor to be observed when the toner concentration equals a reference concentration is equal to or larger than a predetermined value, the control portion performs calibration again when the amount of toner consumed after calibration reaches a predetermined threshold value.

A sensor unit detachably mounted in a main assembly of an image forming apparatus includes a sensor for detecting a detection object on a surface of a movable member, the sensor having a detecting surface positioned to face the surface of the movable member at least when the sensor detects the detection object; a casing portion accommodating the sensor; an air feeding unit, provided in the casing portion, for taking air in through an inlet portion formed by the casing; and a duct for feeding the air discharged from the air feeding unit to a space between the detecting surface and the surface of the movable member.