An image forming apparatus capable of performing color misregistration correction at image forming speeds while reducing downtime. Image forming units form images of different colors. The formed images are transferred to an intermediate transfer belt. A pattern sensor detects color misregistration amounts of color patterns formed on the intermediate transfer belt. A CPU causes the image forming units to form first color patterns at a first speed and the pattern sensor to detect first color misregistration amounts, and causes the former to form second color patterns at a second speed different from the first speed and the latter to detect second color misregistration amounts. The CPU determines third color misregistration amounts at a third speed based on the first and second color misregistration amounts. The third speed is different from the first and second speeds.

A controller, which is a high-voltage power supply apparatus, includes: a secondary transfer high-voltage output device including a first high-voltage generator, which is configured to generate a first voltage having a positive voltage value, and a second high-voltage generator, which is connected in series to the first high-voltage generator, and is configured to generate a second voltage, the secondary transfer high-voltage output device being configured to output an output voltage, which is a sum of the first voltage and the second voltage; and a secondary transfer high-voltage control device, which is configured, in a case where the high-voltage power supply apparatus is switched from a state in which the first high-voltage generator is driven to output a first target voltage as the output voltage, to a state in which a second target voltage is output as the output voltage, to perform feedback control on the second voltage.

An integrated circuit includes a memory, a selecting circuit, and a calibration processing circuit. The memory stores parameter sets for a plurality of color plates. The selecting circuit selects, from the stored parameter sets for the plurality of color plates, a parameter set corresponding to a color plate to be detected by a density sensor. The density sensor is at least one of a plurality of density sensors provided for a printer. The calibration processing circuit executes a print density calibration process on the color plate to be detected based on the selected parameter set corresponding to the color plate to be detected and a value of the color plate detected by the density sensor.

An image forming apparatus includes an image forming unit, a human-body detection unit, an instruction receiver, and a controller. The controller determines whether an adjustment process is to be performed in accordance with a result of a determination, at an end of an image forming process, as to whether a human body is detected. The controller executes the adjustment process when the image forming process is terminated where the human-body detection unit does not detect a human body. The controller starts the image forming process before the adjustment process is executed where a human body is detected and the image forming instruction is received within a predetermined period. The controller executes the adjustment process when the predetermined period has elapsed while the image forming instruction is not received after the end of the image forming process where the human-body detection unit detects a human body.

Changing of a peripheral speed ratio, resulting in change of the developer amount per unit area, enables the detection unit to detect the developer amount with sufficient accuracy.

An image forming apparatus is provided. The image forming apparatus includes a sensor configured to sense a toner concentration, a processor configured to determine at least one of a coring level and a total area coverage (TAC) level according to the detected toner concentration, and an image former configured to print the rendered print data.

In an optical scanning device, light emitting start timings of light emitting parts with respect to a reference light emitting part are stored in a storage part. In a correction mode, a light emitting timing correction control part performs first control for allowing positions of beam spots of the light beams emitted from the light emitting parts to be equal to each other, second control for allowing a light emitting part LD4 to emit a light beam at a plurality of different start timings and patch images to be formed on a intermediate transfer belt 281, and third control for correcting light emitting start timings of light emitting parts LD2 to LD4 on the basis of the start timing of the light emitting part LD4 at which the patch images has the highest concentration.

A toner detection unit is configured by an LED that irradiates light toward an intermediate transfer belt, first and second light receiving elements that respectively receive specular reflection light and diffused reflection light of light irradiated toward the intermediate transfer belt from the LED, a circuit board, and a housing. The LED and the light receiving elements are mounted in a line on the circuit board. The housing is configured to guide, to the first light receiving element, the specular reflection light from a first region within an irradiation region on which light is irradiated from the LED on the intermediate transfer belt, and to guide, to the second light receiving element, the diffused reflection light from a second region which is different from the first region within the irradiation region.

An image forming apparatus includes an image carrier, an endless intermediate transfer belt, a primary transfer member, a secondary transfer member, a displacement amount detecting device, and a control unit. The displacement amount detecting device detects displacement amounts of a reference image in a main-scanning direction and a sub-scanning direction. The reference image is formed on the intermediate transfer belt. The displacement amount detecting device includes a density detecting sensor and a surface potential sensor. The density detecting sensor detects a print density of the reference image formed on the intermediate transfer belt. The surface potential sensor detects a surface potential of the reference image. The displacement amount detecting device simultaneously detects the identical reference image using the density detecting sensor and the surface potential sensor to ensure simultaneous detections of displacement amounts in the main-scanning direction and the sub-scanning direction.

An image forming apparatus includes an image forming unit configured to form an image, a reference member, a sensor including a substrate, a light-emitting element provided on the substrate, a light-receiving element provided on the substrate, and a blocking member provided between the light-emitting element and the light-receiving element on the substrate, the sensor configured to output an output value based on a light reception result of the light-receiving element, a memory storing data related to a relationship between a measurement condition and an offset value, and a controller configured to control the sensor based on a plurality of measurement conditions to acquire an output value corresponding to a measurement result of reflected light from the reference member, and determine a measurement condition for measuring the image based on the acquired output value and the data stored in the memory.