An image forming apparatus includes a control unit configured to be able to perform density adjustment control of forming a reference toner image for image density control on an image bearing member and changing a target value of a toner density based on an image density of the reference toner image detected by an image density detection unit. The control unit limits the target value of the toner density within a predetermined range, and changes frequency of execution of the density adjustment control based on the fact that the target value of the toner density is placed at a boundary value.

An image forming apparatus includes a converting unit, a plurality of image forming units, a scanning unit, a first generating unit, a second generating unit, an intermediate transfer member, a measuring unit, and a controller configured to, after the first generating unit generates an image forming condition, control the plurality of image forming units to form a measurement image, control the measuring unit to measure the measurement image, and control whether to control the second generating unit to generate a conversion condition or not on the basis of a result of the measurement performed on a previous measurement image and a result of the measurement performed on a current measurement image.

In an image forming apparatus, a storage portion stores a target adhesion amount of toner to adhere to an image bearing member at each of gradation levels as a target gradation level and a setting value of a control parameter used for control on the image forming portion at the target gradation level. A first control processor makes an adhesion amount sensor measure an actual adhesion amount corresponding to the setting value and thereafter compares a resultant measured value and the target adhesion amount and corrects the setting value if needed in association with at least one of the target gradation levels as a subject. A second control processor makes the image forming portion output a calibration image used for correcting the target adhesion amount using a period when the first control processor performs processing if there arises a need to correct the target adhesion amount associated with the subject.

An image forming apparatus includes an image forming section, a sensor and a control section. The image forming section forms a first image with at least two kinds of developing agents with different fixation properties. The sensor detects the first image formed on an image formed section by the image forming section. The control section amends deviation of the first image on the image formed section by the image forming section when a detection result of the sensor that the first image formed by the image forming section is not formed at a predetermined position of the image formed section.

An image forming apparatus includes a belt, an image bearing member, a developing portion, a belt transfer portion, a steering roller, a detection portion, a cleaning blade, a control portion, and an instruction input portion. In a case where the input has been performed through the instruction input portion, the control portion executes, before starting image formation for the first time after replacement of the belt, an adjustment mode including a series of processes in which a relationship between the position in the width direction and the amount of tilting of the steering roller is adjusted, and also performs a toner supplying operation of supplying toner by transferring a toner image for supplying toner onto the belt.

An image forming apparatus includes: a density unevenness measurement mode processing portion that, in a density unevenness measurement process, detects density of a density unevenness measurement toner image, which has been formed in a rotational direction of the photoreceptor drum, multiple times in the rotational direction and captures in a memory portion all detected density information associating thereof with rotation phases of the photoreceptor drum; and an image quality adjustment processing portion that, in an image quality adjustment mode, detects density of an image quality adjustment toner image, which has been formed at any position in the rotational direction of the photoreceptor drum, in the rotational direction and corrects detected density information based on density information associated with a rotation phase matching a rotation phase where density of the image quality adjustment toner image has been detected among said all density information having been captured in the memory portion by the density unevenness measurement processing portion.

An image forming apparatus includes an image bearer including a first image portion to bear a first toner image, a second image portion to bear a second toner image, and a non-image portion to bear an adjustment pattern. A transferor forms a transfer nip with the image bearer. A controller controls the power source to output an image bias as a transfer bias to transfer the first toner image and the second toner image onto a first recording medium and a second recording medium, respectively, in the transfer nip when the first image portion and the second image portion pass through the transfer nip and output a non-image bias as the transfer bias when the non-image portion passes through the transfer nip. The controller performs a constant current control on the image bias and performs a constant voltage control when the image bias switches to the non-image bias.

A toner detection unit (optical sensor) includes a first light receiving element configured to receive specular reflection light of first irradiating light, and a second light receiving element configured to receive diffused reflection light of second irradiating light, and a separation component configured to separate irradiating light emitted from an LED into the first and second irradiating light. A housing forms a first opening through which the first irradiating light and the second irradiating light pass and the diffused reflection light to be received by the second light receiving element passes, and a second opening through which the specular reflection light to be received by the first light receiving element passes.

An image forming apparatus that is capable of finding density of an output image with high accuracy even if reflectance of an image bearing member varies. A conversion unit converts image data based on a conversion condition. An image forming unit forms an image based on the converted image data. A measurement unit measures irregular reflection light from a measurement image on the image bearing member. A controller controls the image forming unit to form measurement images, controls the measurement unit to measure irregular reflection light from an area on the image bearing member where the measurement images are not formed, controls the measurement unit to measure the irregular reflection light from the measurement images, selects a measurement result from among measurement results of the measurement images based on the measurement result of the area, and generates the conversion condition based on the selected measurement result.

An image forming apparatus includes an image bearing member, a voltage applying portion, a feeding portion, a detecting portion, a storing portion, a controller for controlling a first operation in which on the basis of a detection result of the detecting portion, a kind of the recording material set in the feeding portion is stored in the storing portion, and a second operation in which an adjusting chart is outputted for adjusting a transfer voltage; and an inputting portion. In response to a single start instruction, the controller is capable of carrying out control so as to execute the first operation and the second operation for outputting the adjusting chart prepared by transferring a plurality of test images onto the recording material from which an index interrelating with the kind of the recording material is detected by the detecting portion in the first operation.