An image forming apparatus includes a light scanning device, a developing portion, a control portion and a storage portion. An evaluation chart includes a first evaluation pattern, a second evaluation pattern, a third evaluation pattern and a fourth evaluation pattern. The first evaluation pattern includes a first dot row and a second dot row, and the third evaluation pattern includes a fifth dot row and a sixth dot row. The fourth evaluation pattern is formed by arranging a plurality of fourth evaluation patches. The fourth evaluation patch includes a seventh dot row and an eighth dot row.

An image forming apparatus includes an image bearing member, an optical sensor configured to detect a pattern image formed on the image bearing member, and an attachment member to which the optical sensor is attached. The optical sensor includes a circuit board, a light emitting element and a light receiving element which are provided on a first side of the circuit board, and a connector provided on a second side opposite to the first side of the circuit board. The attachment member has a surface contacting the second side of the circuit board. In an insertion/removal direction of a cable to be connected to the connector, a first thickness, from the surface, of a part of a portion, contacting the second side, of the attachment member is smaller than a second thickness, from the surface, of a portion, not contacting the second side, of the attachment member.

To provide an image forming apparatus capable of achieving both correction accuracy of skew correction and minimization of a margin between images.

A color shift amount calculator that calculates a color shift amount, and a first skew correction controller and a second skew correction controller that control skew correction of color shift are included. The first skew correction controller controls first skew correction by a mechanical operation by the image former on the basis of a first color shift residual target value set in advance. The second skew correction controller controls second skew correction, by image processing, of the color shift after the control by the first skew correction controller on the basis of a second color shift residual target value set in advance.

An image forming apparatus forms a color image on a recording medium by superimposing images of colors formed by image forming units. The apparatus includes a processor that: acquires a read image by reading the recording medium on which the color image has been formed; forms a register patch outside a job image forming region of the recording medium; and corrects image forming positions of the image forming units based on the read image that includes the register patch. The register patch includes: a leading end patch and a rear end patch formed with a reference color material; and one or more measurement target color patches formed with measurement target color materials between the leading end patch and the rear end patch. The hardware processor corrects the image forming positions based on relative positions of the leading end patch, the rear end patch, and the measurement target color patches.

An image forming apparatus includes a transfer processing portion, a detection processing portion, a correction processing portion, and an adjustment processing portion. The transfer processing portion transfers a detection toner image to outside an output area of a transfer object to which a toner image as an output target is transferred from an image-carrying member. The detection processing portion detects a density of the detection toner image that has been transferred to the transfer object by the transfer processing portion. The correction processing portion corrects a detection result of the detection processing portion based on an amount of toner transferred from the image-carrying member to the output area at a transfer timing when the detection toner image is transferred. The adjustment processing portion adjusts an image forming condition based on the detection result after correction by the correction processing portion.

An image forming apparatus includes an image forming unit configured to form an image on a sheet based on image forming condition, a reader configured to convey the sheet and read a test image on the sheet while the sheet is conveyed, and a controller configured to control the image forming unit to form the image and the test image on a same sheet, control the reader to read the test image on the same sheet, and generate the image forming condition for adjusting a density of an image to be formed by the image forming unit, based on a reading result of the test image by the reader.

An image forming apparatus includes a plurality of image bearers, a plurality of optical writing devices, a plurality of image forming units, and circuitry. The plurality of optical writing devices scan and irradiate the plurality of image bearers with a plurality of light beams according to image data to form latent images on the plurality of image bearers. The plurality of image forming units develop the latent images formed on the plurality of image bearers. The circuitry changes scanning speeds of the plurality of light beams and sets, to each of the plurality of optical writing devices, a correction value of an image misregistration on corresponding one of the plurality of image bearers caused by a change of a scanning speed of corresponding one of the plurality of light beams.

An image forming apparatus includes an image processor configured to convert image data based on a first conversion condition; an image forming unit configured to form an image on a sheet based on the image data converted by the image processor, the image forming unit having an image bearing member on which the image is to be formed, a transfer unit configured to transfer the image from the image bearing member onto the sheet, and a fixing unit configured to fix the image to the sheet; a conveyance roller configured to convey the sheet having the image fixed thereto; a reading unit configured to read a pattern image on the sheet conveyed by the conveyance roller; and a detector configured to detect a pattern image on the image bearing member.

An image forming apparatus includes: an output section that forms an electrostatic latent image onto an image carrier by using light emitted by a light source and outputs an image onto a recording medium by developing the formed electrostatic latent image; a memory that stores a sinusoidal set value representing a correction amount for correcting periodic density variations that occur in an image, which is to be formed, in a subscanning direction and that are caused by a rotating body, and a correction table in which correction amounts for correcting density variations that occur in an image, which is to be formed, in the subscanning direction and that are not caused by a rotating body are each stored in association with a corresponding position in the subscanning direction; and a processor configured to: calculate a first correction amount corresponding to a rotation phase of a rotating body included in the output section on a basis of the sinusoidal set value and retrieve a second correction amount corresponding to a position in the subscanning direction from the correction table when an image is formed in the output section; and perform, by using the calculated first correction amount and the retrieved second correction amount, correction of a density of an image that is formed onto a recording medium.

An image forming apparatus includes an image forming portion, a first acquisition processing portion, a second acquisition processing portion, and an adjustment processing portion. The image forming portion forms an image on a sheet. The first acquisition processing portion acquires a captured image of the sheet. The second acquisition processing portion acquires a specific value that indicates a difference between a gradation value of a pixel that, among pixels included in the captured image acquired by the first acquisition processing portion, corresponds to a higher part of an outer surface of the sheet, and a gradation value of a pixel that, among the pixels included in the captured image, corresponds to a lower part that is lower than the higher part. The adjustment processing portion adjusts an image forming condition of the image forming portion based on the specific value acquired by the second acquisition processing portion.