Abstract: A liquid circulation device includes a circulation passage, a liquid feeding device, a pressure sensor, and control circuitry. Through the circulation passage, liquid circulates to be supplied to and collected from a circulatory liquid discharge head. The liquid feeding device is configured to circulate the liquid through the circulation passage. The pressure sensor is configured to detect a pressure of the circulation passage. The control circuitry configured to acquire a characteristic indicating a relationship among a drive amount of the liquid feeding device, discharge information of the liquid discharged from the liquid discharge head, and a pressure detection value of the circulation passage; and change, based on the characteristic acquired, at least one of a control parameter and a calculation expression used to control the liquid feeding device.

Abstract: A liquid circulation device includes a circulation passage, a liquid feeding device, a pressure sensor, and control circuitry. Through the circulation passage, liquid circulates to be supplied to and collected from a circulatory liquid discharge head. The liquid feeding device is configured to circulate the liquid through the circulation passage. The pressure sensor is configured to detect a pressure of the circulation passage. The control circuitry configured to acquire a characteristic indicating a relationship among a drive amount of the liquid feeding device, discharge information of the liquid discharged from the liquid discharge head, and a pressure detection value of the circulation passage; and change, based on the characteristic acquired, at least one of a control parameter and a calculation expression used to control the liquid feeding device.

Abstract: A liquid circulation device includes a circulation passage, a liquid feeding device, a pressure sensor, and control circuitry. Through the circulation passage, liquid circulates to be supplied to and collected from a circulatory liquid discharge head. The liquid feeding device is configured to circulate the liquid through the circulation passage. The pressure sensor is configured to detect a pressure of the circulation passage. The control circuitry configured to acquire a characteristic indicating a relationship among a drive amount of the liquid feeding device, discharge information of the liquid discharged from the liquid discharge head, and a pressure detection value of the circulation passage; and change, based on the characteristic acquired, at least one of a control parameter and a calculation expression used to control the liquid feeding device.

Abstract: A liquid discharge device includes a storage tank, a discharge head, a liquid feeder, a supply tank, a liquid path, a branch path, and a flow regulator. The liquid feeder is configured to feed liquid from the storage tank to the discharge head in a liquid feed direction. The supply tank is disposed upstream of the discharge head in the liquid feed direction, to store the liquid fed by the liquid feeder while being in a state open to atmosphere. The liquid path is configured to flow the liquid from the liquid feeder to the supply tank. The branch path is connected to the liquid path and configured to cause part of the liquid to branch from the liquid path. The flow regulator is disposed downstream of the discharge head in the liquid feed direction and configured to control a flow rate of the liquid flowing into the discharge head.

Abstract: A liquid circulation device includes a circulation passage, a liquid feeding device, a pressure sensor, and control circuitry. Through the circulation passage, liquid circulates to be supplied to and collected from a circulatory liquid discharge head. The liquid feeding device is configured to circulate the liquid through the circulation passage. The pressure sensor is configured to detect a pressure of the circulation passage. The control circuitry configured to acquire a characteristic indicating a relationship among a drive amount of the liquid feeding device, discharge information of the liquid discharged from the liquid discharge head, and a pressure detection value of the circulation passage; and change, based on the characteristic acquired, at least one of a control parameter and a calculation expression used to control the liquid feeding device.

Abstract: A liquid discharge device includes a storage tank, a discharge head, a liquid feeder, a supply tank, a liquid path, a branch path, and a flow regulator. The liquid feeder is configured to feed liquid from the storage tank to the discharge head in a liquid feed direction. The supply tank is disposed upstream of the discharge head in the liquid feed direction, to store the liquid fed by the liquid feeder while being in a state open to atmosphere. The liquid path is configured to flow the liquid from the liquid feeder to the supply tank. The branch path is connected to the liquid path and configured to cause part of the liquid to branch from the liquid path. The flow regulator is disposed downstream of the discharge head in the liquid feed direction and configured to control a flow rate of the liquid flowing into the discharge head.

Abstract: An image forming apparatus includes a latent image bearer, a charger to charge the latent image bearer with a charging bias obtained by superimposing a charge fluctuation voltage to reduce an image density fluctuation on a direct current charging voltage, a writing device to write a latent image on the latent image bearer with writing intensity obtained by superimposing fluctuating writing intensity to reduce an image density fluctuation on constant writing intensity, a developing sleeve to which a developing bias obtained by superimposing a fluctuating developing voltage to reduce an image density fluctuation on a direct current developing voltage is applied to develop the latent image, and circuitry to control the charging bias, the writing intensity, and the developing bias. The circuitry changes the charge fluctuation voltage and the fluctuating developing voltage depending on whether the writing device writes the latent image with the fluctuating writing intensity.

Abstract: An image forming apparatus includes a latent image bearer; a writing device configured to write a latent image onto the latent image bearer; a detection device configured to detect, at a plurality of positions, a density of a toner image obtained through development of the latent image; and a controller configured to correct a writing intensity of the writing device to correct an uneven density based on detection values of the detection device. The controller determines whether each of the detection values is pass or fail. In response to a determination that a detection value is fail, the controller corrects the wiring intensity based on another detection value determined to be pass at a position different from a position at which the detection value is determined to be fail, instead of correcting the writing intensity based on the detection value determined to be fail.

Abstract: An image forming apparatus includes an image forming unit and a controller. The image forming unit includes a latent image bearer, a charger to charge the latent image bearer, an exposure device to expose a latent image on the surface of the latent image bearer, and a developing device to develop the latent image with a developer. The controller executes an image forming process, a first fluctuation control that cyclically changes a developing bias supplied to the developing device based on predetermined first pattern data, and a second fluctuation control that cyclically changes a charging bias supplied to the charger based on predetermined second pattern data, in parallel. The controller executes a determination process to determine whether the controller executes the first fluctuation control. When the controller determines not to execute the first fluctuation control, the controller determines not to execute the second fluctuation control, too.

Abstract: An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.

Abstract: An image forming apparatus includes a latent image bearer; a writing device configured to write a latent image onto the latent image bearer; a detection device configured to detect, at a plurality of positions, a density of a toner image obtained through development of the latent image; and a controller configured to correct a writing intensity of the writing device to correct an uneven density based on detection values of the detection device. The controller determines whether each of the detection values is pass or fail. In response to a determination that a detection value is fail, the controller corrects the wiring intensity based on another detection value determined to be pass at a position different from a position at which the detection value is determined to be fail, instead of correcting the writing intensity based on the detection value determined to be fail.

Abstract: An image forming apparatus includes a latent image bearer, a charger to charge the latent image bearer with a charging bias obtained by superimposing a charge fluctuation voltage to reduce an image density fluctuation on a direct current charging voltage, a writing device to write a latent image on the latent image bearer with writing intensity obtained by superimposing fluctuating writing intensity to reduce an image density fluctuation on constant writing intensity, a developing sleeve to which a developing bias obtained by superimposing a fluctuating developing voltage to reduce an image density fluctuation on a direct current developing voltage is applied to develop the latent image, and circuitry to control the charging bias, the writing intensity, and the developing bias. The circuitry changes the charge fluctuation voltage and the fluctuating developing voltage depending on whether the writing device writes the latent image with the fluctuating writing intensity.

Abstract: An image forming apparatus includes an image bearer, a toner image forming device, a plurality of image density detectors, and a controller. The plurality of image density detectors are disposed at predetermined intervals opposite the image bearer in a width direction of the image bearer. The controller causes the toner image forming device to form toner image patterns having an identical density at the plurality of positions on the image bearer and the plurality of image density detectors detects a density of the toner image patterns. Based on the detected density of the toner image patterns, the controller identifies multiple cyclic fluctuations of the density of the toner image patterns and adjusts an image forming condition based on the multiple cyclic fluctuations of the density of the toner image patterns to decrease an amplitude caused by the multiple cyclic fluctuations of the density of the toner image patterns.

Abstract: An image forming apparatus includes an image forming device, an image density detector, and a processor. The processor controls the image forming device to form a first test toner image, and controls the image density detector to detect an image density at the plurality of positions of the first test toner image. The processor adjusts an image forming condition so that the image density detected at each of the plurality of positions becomes a target image density, controls the image forming device to form a second test toner image based on the adjusted image forming condition, controls the image density detector to detect an image density at the plurality of positions of the second test toner image, determines whether a streak exists in the second test toner image based on the detected image densities, and executes a countermeasure to prevent an occurrence of the streak.

Abstract: An image forming apparatus includes an image forming unit and a controller. The image forming unit includes a latent image bearer, a charger to charge the latent image bearer, an exposure device to expose a latent image on the surface of the latent image bearer, and a developing device to develop the latent image with a developer. The controller executes an image forming process, a first fluctuation control that cyclically changes a developing bias supplied to the developing device based on predetermined first pattern data, and a second fluctuation control that cyclically changes a charging bias supplied to the charger based on predetermined second pattern data, in parallel. The controller executes a determination process to determine whether the controller executes the first fluctuation control. When the controller determines not to execute the first fluctuation control, the controller determines not to execute the second fluctuation control, too.

Abstract: An image forming apparatus includes a rotatable image bearer, a toner image forming device, an image reader, and a control unit. The toner image forming device forms a test toner image on the image bearer. The image reader reads the test toner image and a predetermined reference member. The control unit calculates an amount of toner contained in the test toner image based on image data from the test toner image. Based on image data from the reference member, the control unit selects a position of a pixel to be used for calculation of the amount of toner contained in the test toner image from pixels included in the image data from the reference member, to calculate the amount of toner contained in the test toner image from data of a pixel located at the position thus selected among pixels included in the image data from the test toner image.

Abstract: An image forming apparatus includes an image bearer, a toner image forming device, a plurality of image density detectors, and a controller. The plurality of image density detectors are disposed at predetermined intervals opposite the image bearer in a width direction of the image bearer. The controller causes the toner image forming device to form toner image patterns having an identical density at the plurality of positions on the image bearer and the plurality of image density detectors detects a density of the toner image patterns. Based on the detected density of the toner image patterns, the controller identifies multiple cyclic fluctuations of the density of the toner image patterns and adjusts an image forming condition based on the multiple cyclic fluctuations of the density of the toner image patterns to decrease an amplitude caused by the multiple cyclic fluctuations of the density of the toner image patterns.

Abstract: An image density detector for detecting image density of an image borne by an image bearer includes a reference board, a light emitter, a light receiver, an image density calculator, and an image density detecting condition corrector. The reference board has a spectral reflectance distribution closer to a spectral reflectance distribution of the image forming material than a spectral reflectance distribution of white. The light emitter emits light to the reference board and the image borne by the image bearer. The light receiver receives the light reflected from the image and the reference board. The image density calculator calculates the image density of the image based on an output of the light receiver receiving the light reflected from the image. The image density detecting condition corrector corrects an image density detecting condition based on an output of the light receiver receiving the light reflected from the reference board.

Abstract: An image forming apparatus includes an image bearer, an image forming device to form a toner image on the image bearer, a transfer device to transfer the toner image to a recording medium, a line sensor as an image density sensor to detect image density of the toner image, and a controller operatively connected to the image density sensor. The image density sensor is disposed so as to be shorter in a rotational direction of the image bearer than in a width direction of the image bearer perpendicular to the rotational direction of the image bearer. The controller forms a shading pattern image including a plurality of patches on the image bearer, and detects image density of the plurality of patches, so as to control image density. The shading pattern image is shorter in the rotational direction of the image bearer than in the width direction of the image bearer.

Abstract: An image forming apparatus includes a rotatable image bearer, a toner image forming device, an image reader, and a control unit. The toner image forming device forms a test toner image on the image bearer. The image reader reads the test toner image and a predetermined reference member. The control unit calculates an amount of toner contained in the test toner image based on image data from the test toner image. Based on image data from the reference member, the control unit selects a position of a pixel to be used for calculation of the amount of toner contained in the test toner image from pixels included in the image data from the reference member, to calculate the amount of toner contained in the test toner image from data of a pixel located at the position thus selected among pixels included in the image data from the test toner image.