A color accuracy verification device includes: a hardware processor that: acquires a colorimetric value for each color patch of color accuracy verification charts generated by a plurality of printers; stores the colorimetric value in time series; sets a target printer to carry out color accuracy verification; and verifies color accuracy based on: the colorimetric value of the target printer stored in the hardware processor; and a verification reference value set in advance; and a display that displays a verification result by the hardware processor for the target printer.

According to one embodiment, an image forming apparatus of the embodiment includes a roller, a plurality of developing units, an image forming unit, a sensor, and a control unit. The rollers carry a sheet. The plurality of developing units include different types of developing materials. The image forming unit forms a plurality of images on a transfer belt by the developing materials of each of the plurality of developing units. The sensor reads the plurality of images formed on the transfer belt. The control unit controls the speed of the roller based on the positions of the plurality of images read by the sensor.

An example shutter unit includes a motor including a driving shaft to rotate in a first rotation direction and to rotate in a second rotation direction opposed to the first rotation direction, a first shutter part to selectively expose a light window by receiving a driving force transferred from the driving shaft when the driving shaft rotates in the first rotation direction or the second rotation direction, and a second shutter part to selectively expose a sensor by receiving the driving force transferred from the driving shaft when the driving shaft rotates in the second rotation direction.

An image forming apparatus comprises a first temperature detector to detect a temperature of a first portion of an optical scanning device in a printer. The first portion is proximate to a heat generating element in the optical scanning device. A second temperature detector is provided to detect a temperature of a second portion of the optical scanning device, which is farther from the heat generating element than the first portion. A controller is configured to perform alignment control for correcting a color positional shift of the printer when either a detected temperature change of the first portion is greater than or equal to a first threshold value or a detected temperature change of the second portion is greater than or equal to a second threshold value.

A natural frequency measuring device includes a receiving unit and a measuring unit. The receiving unit receives information of an image formed on a recording medium with vibrations of different frequencies provided to a member used to form the image. The measuring unit measures a natural frequency of the member from a frequency response characteristic using a misregistration amount of the image represented by the information of the image received by the receiving unit.

A base material processing apparatus includes first and second edge sensors and a displacement amount calculation part. The first edge sensor acquires a first detection result (R1) by detecting the position of an edge of a base material in a width direction at a first detection position. The second edge sensor acquires a second detection result (R2) by detecting the position of the edge of the base material at a second detection position. The displacement amount calculation part calculates the amount of displacement in the position of the base material in the transport direction or the amount of difference in the transporting speed of the base material on the basis of the first and second detection results (R1, R2). Thus, the amount of displacement in the position or the amount of difference in the transporting speed can be detected without depending on images such as register marks.

An image forming apparatus includes a controller configured to execute: a task that measures a plurality of first color patterns; a task that, on the basis of a first output value corresponding to a measurement result of the first color patterns, determines a threshold value; a measurement task that measures a plurality of second color patterns; and a task that detects an amount of color misregistration on the basis of a result of a comparator comparing a second output value corresponding to a measurement result of the second color patterns with a threshold value corresponding to each of the second color patterns. In the measurement task, the controller controls whether or not to set the threshold value to the threshold value corresponding to each of the second color patterns on the basis of the first output value.

An image forming apparatus includes: a housing in which a light source, a laser scanning member, a light detecting portion configured to detect light incident on a predetermined position in a scanning path of the light scanned by the laser scanning member, and a scanning lens configured to cause the light scanned by the laser scanning member to be scanned at an equal speed on an image carrier, are disposed; a temperature gradient detecting portion, configured to detect a temperature gradient of the housing, a heater configured to heat the image carrier or a sheet; and a correction processing portion configured to correct the emission start timing based on the temperature detected by the temperature gradient detecting portion, and a predetermined expression, and change content of the expression based on an operation state of the heater at a start of an image formation process.

An image forming apparatus includes an image carrier, an optical member, a drive device, a motive device, and a control device. On a surface of the image carrier, a scanning line is formed, through a scanning operation with scanning light. The optical member emits the scanning light to the image carrier. The drive device changes a posture of the optical member, to adjust a skew of the scanning line on the image carrier. The motive device drives the drive device. The control device controls the motive device. Further, the control device decides that at least one of the drive device and the motive device are malfunctioning, when a skew amount remains higher than a predetermined permissible value, despite changing the posture of the optical member a predetermined number of times, through control of the drive device by the motive device.

An electrophotographic color image forming apparatus develops an electrostatic latent image with a developer to form an image and includes a photoconductor and an optical writing device. The writing device includes a light-emitting element, a light emission control element, a deflector element, a synchronization detection element, a memory, and processing circuitry. The memory stores a first light amount of the light-emitting element when a color shift is corrected. The processing circuitry corrects the color shift by adjusting a write start timing, and corrects a detection shift generated when a light amount of light incident on the synchronization detection element fluctuates. The processing circuitry calculates a detection shift correction value of the detection shift of the synchronization detection element, using the first light amount and a second light amount determined as a lighting condition of the light-emitting element, and adds the detection shift correction value to a color shift correction value.