Abstract: An image forming apparatus adjusts a gamma-LUT of a gamma correction circuit in accordance with density data on a measurement image formed on a photosensitive drum. A CPU selects a conversion table in association with the image formation condition such as laser power of a semiconductor laser, fixing temperature of a fixing device, or a charge in a developer. A luminance/density converting portion converts luminance data on the measurement image into density data using the conversion table selected by the CPU. The CPU adjusts a contrast potential and a gamma-LUT using this density data.

Abstract: A method of controlling toner concentration in an image forming device by determining a charge per unit mass of toner in a mixture of toner and carrier and adding toner to the mixture if the charge per unit mass of the toner is higher than a predetermined threshold. Other methods and devices are disclosed.

Abstract: In an image forming apparatus that forms an electrostatic latent image for detection on a photosensitive member by light irradiation and performs color-misregistration correction control on the basis of detection of a change in detection current due to the detecting electrostatic latent image passing through a processing unit disposed close to the periphery of the photosensitive member, the intensity of at least one of the apply voltage of the processing unit and the output of the light irradiation unit is set higher than that during normal image formation.

Abstract: An optical-writing control device calculates correction values for use in correcting a transfer position at which developing-agent images are to be transferred onto a sheet, and overlaying positions at which the developing-agent images are to be overlaid, based on a detection signal output from a sensor upon detection of a correction pattern for use in correcting the transfer position and a correction pattern for use in correcting the overlaying positions. A timing of detecting the pattern for use in correcting the overlaying positions is determined based on a correction value calculated based on the detection signal output upon detection of the pattern for use in correcting the transfer position. The pattern for use in correcting the transfer position is caused to have a width, in the main-scanning direction, that is wider than the width in the main-scanning direction of the pattern for use in correcting the overlaying positions.

Abstract: An image forming apparatus includes an image bearing member, an image forming device for forming a toner image on the image bearing member, a recording material, a transfer device for transferring the toner image from the image bearing member to the recording material, a transfer belt for carrying the recording material, a first cleaning member, a second cleaning member, and a voltage control device. When continuously forming toner images on sheets of the recording material, a detection toner image is formed on the image bearing member between images to be formed on sheets of the recording material. The first cleaning member cleans the image bearing member. The second cleaning member cleans the transfer belt. The voltage control device controls the voltage applied to the transfer device so that the number of operations to clean the detection toner image is higher for the second cleaning member than the first cleaning member.

Abstract: In a wet-type image forming apparatus, a plurality of patch images are successively transferred to a recording medium corresponding to a plurality of transfer biases obtained as bias value of the transfer bias is changed; density detecting unit measures image density of each of the plurality of patch images on the recording medium and detects a range of bias values of transfer bias in which the image density of patch image is substantially saturated; and the bias value of transfer bias when a normal image is formed on the recording medium is set to be within the range of bias values of transfer bias in which the image density of patch image is substantially saturated and to be not larger than absolute value of the bias value at which the image density of patch image is substantially saturated.

Abstract: An image forming apparatus includes a image forming unit; an image bearing member having a surface to bear a toner image and a test pattern; the surface having a first time-surface positioned identical to the test pattern, an integer multiple of revolutions upstream or downstream from the test pattern in a surface movement direction, and a second time-surface positioned different from the test pattern, shorter than one revolution upstream or downstream from the test pattern; a reflection light detector to detect the amount of light reflected from the test pattern and the first and second time-surfaces of the image bearing member; and a controller to control the image forming unit based on the detection result and determine whether to execute a first-surface control to detect at least the first time-surface or a second-surface control to detect only the second time-surface based on use condition of the image forming apparatus.

Abstract: An apparatus includes a unit configured to judge a border between two patch images among a plurality of patch images formed on the recording material, based on change in the amount of the light beam of at least one noticed wavelength detected by a detection unit; a unit configured to calculate a color value of a patch image from the amount of the light beam of each wavelength detected by the detection unit; and a control unit configured to control an accumulation period of charge for the photoelectric conversion at the detection unit. The control unit is further configured to make the accumulation period of the detection unit shorter when judging the border between the two patch images than when calculating the color value of each of the two patch images.

Abstract: An image forming apparatus includes an image forming unit, a density-corrected image forming unit, a measurement unit, an image correction unit, and a fixing unit. The image forming unit forms an image represented by image data as a toner image. The density-corrected image forming unit forms a density corrected image. The measurement unit measures the density of the density corrected image. The image correction unit performs image correction such that a non-halftone image is formed as a halftone image whose halftone percentage is less than 100%. The fixing unit, in a case where the image correction unit performs image correction for image data, fixes a toner image on a recording medium with at least one of an increased fixing temperature, an increased fixing time period, and an increased fixing pressure, the toner image being based on the image data for which image correction has been performed.

Abstract: An image forming apparatus includes an image bearer; a charger to charge the image bearer; an electrostatic latent image former to form an electrostatic latent image on the image bearer; an image developer to develop the electrostatic latent image with a toner to form a visual toner image; a transferer to transfer the toner image on a transfer material; a toner concentration calculator to calculate a concentration of the toner; and an optical detector. At least a toner patch image is formed on the image bearer with an irradiation quantity set such that an irradiated part potential is larger than a developing condition, the toner patch image is read by the optical detector, and the charging condition is corrected on the basis of a difference between a toner concentration of the toner patch image and a target toner concentration.

Abstract: In an image forming apparatus, an image forming device have an operating part and is configured to form an image at an image formation position on an imaging target. A control device is configured to control the image forming device to start performing an image forming process, determine an adjustment amount regarding the image formation position based on an operation amount of the operating part measured during a period of time from a first specified timing in a previous image forming process to a second specified timing in or before a current image forming process, and adjust, based on the adjustment amount, the image formation position where an image is formed pursuant to the current image forming process.

Abstract: A moving device assembly includes a moving device and a shield. The moving device is movable between a first position and a second position, to move a detector including a detection surface relative to an opposing member disposed opposite the detector. The shield shields the detection surface of the detector. As the moving device is at the first position, the detector is at a proximal position at which the detector is near the opposing member, and as the moving device is at the second position, the detector is at a shield position at which the detector is separated from the opposing member and the detection surface of the detector is shielded by the shield.

Abstract: An image forming apparatus includes a latent image bearing member, a charging unit, a charging power source, a latent image writing unit, a development unit, a transfer unit, a toner detector, and a controller. The controller causes a background fog pattern to be formed on a surface of the latent image bearing member. In addition to the background fog pattern, the controller causes a latent image to be developed to form a toner image used for position identification on the surface of the latent image bearing member. The controller identifies a time when the toner image used for position identification has entered a detection range of the toner detector based on a change in outputs of the toner detector to determine a time when each of sections of the background fog pattern enters the detection range based on the identified time.

Abstract: An image forming apparatus includes an update unit configured to cause an image forming unit to form a first measurement image, cause a measurement unit to measure the first measurement image, and update a process condition based on a measurement result; a first determination unit configured to cause the image forming unit to form a plurality of second measurement images, cause the measurement unit to measure the plurality of second measurement images, and determine the process condition based on a measurement result, the plurality of second measurement images being formed according to a plurality of test process conditions; and a second determination unit configured to determine the plurality of test process conditions, based on an environment information obtained by an obtainment unit and the process condition updated by the update unit.

Abstract: An image forming apparatus includes: a photosensitive member; an exposure portion; a developing portion; a sensor; a supply portion; a controller for controlling a developer amount based on density information outputted from the sensor after an electrostatic image for a supply control toner image is exposed to light under an exposure condition for supply control and then is developed into the supply control toner image, which is then detected by the sensor; a storing portion; and an exchange detecting portion. The controller is capable of executing an operation in a mode, in which the exposure condition for the supply control, based on information detected by the exchange detecting portion. In the mode, the exposure condition for the supply control is controlled based on the information stored in the storing portion and a detection result, by the sensor, of a control toner image formed during the operation in the mode.

Abstract: An image forming apparatus includes a measurement unit configured to irradiate a measurement image with light, and measure the light reflected from the measurement image, a white reference plate disposed in a position opposite to the measurement unit, a correction unit configured to correct a measurement result of the measurement image, based on a measurement result of the white reference plate acquired by the measurement unit, and a temperature detection unit configured to detect temperature in a vicinity of the measurement unit, wherein the correction unit corrects, in a case where a difference between a temperature detected by the temperature detection unit and a temperature shown when previously measuring the white reference plate is less than a predetermined value, a measurement result of the measurement image using a previous measurement result of the white reference plate without measuring the white reference plate with the measurement unit.

Abstract: An image forming apparatus includes an image forming unit, which forms a test pattern for density control on the image carrier; and first and second light receiving elements, which receive reflected light irradiated by a light emitting element. A spot diameter of a reflected light received by the first light receiving element is smaller than a spot diameter of a reflected light received by the second light receiving element, and a number of sampling of the test pattern in line with a movement direction of a surface of the image carrier by the first light receiving element is greater than that of the test pattern in line with the moving direction by the second light receiving element.

Abstract: Patch background data at each position of a background where a toner patch is formed in the second rotation is estimated from background measurement data at a plurality of positions detected in the first rotation and patch neighborhood measurement data detected in the second rotation at a plurality of positions where no toner patch is formed. Since the apparatus can execute density measurement before the light emission amount of a density sensor stabilizes, the time required for density measurement can be shorter than before. Since the change ratio of the light emission amount and the variation of the reflected light amount from the background are reflected on the patch background data, the density measurement accuracy can be improved.

Abstract: An image forming apparatus capable of making image quality more stable than in the prior art. An electrostatic latent image is formed on the surface of a photosensitive member based on an image signal. A developing device develops the electrostatic latent image on the photosensitive member by toner to thereby form a patch image. An optical sensor detects the density of the patch image. A toner charge amount is calculated from the density detected by the optical sensor, and a change in the toner charge amount is predicted based on a plurality of results of the calculation of the toner charge amount. The image forming apparatus generates a ?LUT for use in correcting the relationship between the image signal and the density based on the predicted change in the toner charge amount.

Abstract: When a toner image formed on the surface of a photosensitive drum is transferred onto an intermediate transfer belt, a transfer bias is applied to a primary transfer portion. When a patch formed in an upstream image forming station and transferred onto the intermediate transfer belt and a patch formed on the surface of the photosensitive drum pass through the primary transfer portion, a passing bias different from the transfer bias is applied to the primary transfer portion. A control section controls a laser beam scanner as an exposure member not to expose the surface of the photosensitive drum to which the passing bias is applied.

Abstract: Toner printers are provided. In one printer a toner image is printed according to first printing instructions. An amount of toner in a target area of the toner image is determined and second printing instructions are generated causing the toner printer to print at least one subsequent toner image based upon the determined amount of first toner.

Abstract: Control parameters of a printing device are optimized using a process model to reduce a process tone reproduction curve (TRC) error between a process TRC and a desired TRC. Tone-corrected halftone levels for the printing device are generated using a sensor model to reduce a printing device TRC error between a TRC of the printing device and the desired TRC, based on color patches printed by the printing device using the control parameters as have been optimized, as measured by one or more sensors of the printing device.

Abstract: An image forming apparatus includes an image bearing member which bears a toner image, an intermediate transfer member which bears the toner image transferred from the image bearing member, an endless recording material-conveying member which conveys a recording material, and a transfer portion which transfers the toner image to the recording material conveyed from the intermediate transfer member by the recording material-conveying member, wherein a perimeter of the intermediate transfer member is set to substantially an integral multiple of a perimeter of the recording material-conveying member.

Abstract: An image forming apparatus comprises: an extraction unit that analyzes an input print job and extracts a color used in a plurality of pages of the print job; a forming unit configured to form a patch image of the color extracted by the extraction unit; a determining unit configured to measure the patch image formed by the forming unit and to determine an amount of color fluctuation from a reference value for the extracted color; and a correction unit configured, when printing the input print job, to correct the extracted color by using the amount of color fluctuation determined by the determining unit.

Abstract: An image forming device includes: a secondary transfer roller configured to secondarily transfer a toner image transferred to an intermediate transfer belt, to a transfer paper; separating plates; and a power supply circuit configured to apply bias voltages to the separating plates. The separating plates are configured to separate the transfer paper from the intermediate transfer belt when the bias voltages are applied to the separating plates. The separating plates include two or more separating plates installed along a direction perpendicular to the transfer paper conveying direction. The bias voltages are applied to the separating plates independently of each other depending on a toner amount distribution of the toner image transferred to the transfer paper, in the direction perpendicular to the transfer paper conveying direction.

Abstract: A method for calibrating specialty toner, the method includes providing a substrate; depositing an invariant or substantially invariant laydown of a color toner on the substrate; depositing a varying laydown of the specialty toner; fusing the color toner and specialty toner to the substrate; measuring a color response signal of the substrate, color toner, and specialty toner; calculating a color response curve as function of the varying laydown of the specialty toner; comparing the color response curve to a target color response curve; and modifying printing parameters of the specialty toner to set the color response curve equal to or substantially equal to the target color response curve.

Abstract: Various methods and devices transfer test patches of marking material from a marking device of a printing apparatus to a transfer surface of the printing apparatus, optically measure the density of the test patches on the transfer surface using an optical sensor of the printing apparatus, and measure the electrostatic differences in charge of the transfer surface as the test patches on the transfer surface move by an electrostatic sensor of the printing apparatus. Such methods and devices adjust settings of the marking device based on output from the electrostatic sensor alone, or based on a combination of the output from the optical sensor and converted output from the electrostatic sensor.

Abstract: A Zener diode contacts an inner periphery surface of an intermediate transfer belt, and an opposing roller which opposes a detecting member is electrically insulated, in a configuration where transfer is performed at multiple photosensitive drums while an electrical current is applied in a peripheral direction of the intermediate transfer belt.

Abstract: An image forming apparatus includes a preliminary toner image forming unit, a detecting unit, an adjusting unit, an obtaining unit, an activation grasping unit, a determining unit, and a preparation unit. The preliminary toner image forming unit causes an inactive image forming unit to form a preliminary toner image and causes the preliminary toner image to be transferred onto a transfer body. The detecting unit detects the preliminary toner image. The adjusting unit adjusts quality of a toner image. The obtaining unit obtains information regarding an image to be output. The activation grasping unit grasps an estimated activation timing. The determining unit determines whether a time period until the estimated activation timing has become equal to an image quality adjustment period. The preparation unit causes the preliminary toner image forming unit to transfer the preliminary toner image and causes the adjusting unit to adjust the quality of the toner image.

Abstract: An image forming apparatus, includes an image forming unit configured to form a reference pattern and a test pattern on a sheet, a measurement unit configured to detect the reference pattern formed on the sheet and to measure the test pattern formed on the sheet, and a control unit configured to control a measurement timing of the test pattern by the measurement unit according to a detection interval between two reference patterns detected by the measurement unit.

Abstract: An image forming apparatus performs density correction. An image forming section forms a density detection image on a belt. A light source irradiates the image with light. A light receiving section receives light reflected from the image and outputs a plurality of intensity signals of the received light. An intensity obtaining section drives the belt and the light source, thereby illuminating the image a first number of times at intervals of a first distance as the belt runs, and the light receiving section receives the light reflected from the image, the first number of times being determined by at least the first distance and a second distance in which the first distance lies. A selecting section selects a second number of levels of light intensity from the plurality of intensity signals. A density correcting section performs print density correction using the second number of levels of light intensity.

Abstract: An optical sensor configured to irradiate an object area with light and receive reflected light, amplify a voltage in accordance with the reflected light by an amplifier circuit and a resulting voltage, the optical sensor comprising a recording medium recorded with information indicating a noise component calculated, based on characteristics of an input voltage and an output voltage of the amplifier circuit.

Abstract: An image forming apparatus includes an image carrier, an image forming unit, a density sensor, a gradation characteristic data generator, and a gradation corrector. The density sensor includes a low-pass filter to remove a high-frequency component of an output of the image density sensor. The gradation characteristic data generator forms a gradation correction pattern on the image carrier. The gradation correction pattern is a continuous gradation pattern including first and second patterns. The gradation characteristic data generator continuously detects image density of the continuous gradation pattern and background areas adjacent to the continuous gradation pattern to generate the gradation characteristic data. The gradation characteristic data generator forms a compensation pattern on the image carrier next to and continuous with a leading end of the first pattern in an image carrier rotational direction, to compensate for a response delay of the output of the density sensor due to the low-pass filter.

Abstract: Disclosed is an image forming apparatus including: an image forming unit to form an image on paper fed from the selected feed tray; a density sensor to measure a density of the image formed on the paper; and a control unit to control execution of an output paper density adjustment in accordance with a result obtained by forming a test image on the paper by using the image forming unit and by measuring the density of the test image formed on the paper by using the density sensor, wherein the control unit executes the output paper density adjustment by changing the feed tray for feeding the paper, from the feed tray designated in a print job to the substitute feed tray at a predetermined timing while the print job is executed, regardless of the paper setting information related to the substitute feed tray.

Abstract: An image forming apparatus includes an image bearing member, a controller controls a first and the second image forming unit to form a measurement image on the image bearing member, wherein the measurement image is composed with a first measurement image having a first color, and a second measurement image having a second color with a lower reflectance than the first color, a radiation unit emits a irradiation light to the measurement image, a light receiving unit receives a reflected light from the measurement image, a comparison unit compares a light amount of the reflected light from the measurement image with a threshold value, and a changing unit increases the threshold value, if a measurement time period during which a light amount of the reflected light from the measurement image is equal to or greater than the threshold value is longer than a predetermined time period.

Abstract: A printing device including a printing unit that prints an image with print agent, a calibration unit that executes a calibration process, a specifying unit that specifies a usage amount of the print agent, and a control unit that controls the calibration unit to execute the calibration process at a lower frequency when the specifying unit specifies a lower amount as the usage amount. The calibration process is for printing a mark with the print unit, detecting the mark, and calculating a calculation value based on a detection result.

Abstract: Disclosed is an image processing device including: a sample output unit to instruct a print device to successively print test images on a plurality of sheets of the recording paper; a profile preparing unit to prepare a plurality of profiles of the density unevenness in the sub-scanning direction in the plurality of sheets of the recording paper, from measuring data obtained by optically reading the test images; an analyzing unit to analyze the profiles by arranging the profiles in a printing order apart from each other so as to correspond to intervals of the sheets of the recording paper, and to detect a long period density unevenness in the sub-scanning direction, which has a long period extending through the plurality of sheets of the recording paper; and a correction data preparing unit to prepare correction data for removing the long period density unevenness.

Abstract: An image forming apparatus includes a plurality of white reference plates, a plurality of measurement units configured to be arranged in positions opposed to the respective plurality of white reference plates, irradiate the white reference plates with light, and measure reflected light from the white reference plates, and a determination unit configured to determine an abnormality of the plurality of white reference plates by using respective measurement results measured by the plurality of measurement units.

Abstract: A thermal fixing device includes a fixing member, a flexible endless belt, a flexible endless belt, a rotary pressure member, a heating unit, and a rotation detector. The flexible endless belt is disposed on an outer circumferential surface of the fixing member. The rotary pressure member is disposed parallel to and pressing against the fixing member via the endless belt. The heating unit heats the endless belt. The rotation detector detects a rotation speed of the endless belt. The heating unit is powered off when the rotation speed of the endless belt detected by the rotation detector is at or below a predetermined threshold value.

Abstract: When a toner charging amount for toner in a liquid developer conveyed to a development portion is set, a wet-type image formation apparatus performs a sensing operation in which a sensing unit senses image densities of a plurality of patch images formed at different development biases with the toner charging amount being set to a constant value, and a setting operation in which, in a case where a control unit calculates current development characteristics based on the image densities of the plurality of patch images sensed by the sensing unit, and determines that the current development characteristics are not included within a set target range, the control unit controls a charging unit to set the toner charging amount such that the development characteristics are included within the set target range.

Abstract: An image forming apparatus is disclosed, including a light source; a drum; an optical scanning apparatus; and an endless belt. The image forming apparatus further includes a pattern forming unit which forms, on the endless belt along a conveying direction of the endless belt, a density fluctuation detecting pattern having a period; a density sensor which detects the density fluctuating detecting pattern and outputs a density signal including information on density fluctuations in the conveying direction of the endless belt; and a period detecting sensor which detects the period included in the density fluctuations.

Abstract: An image forming apparatus including an image forming unit configured to form an image on the image bearing member, a transfer unit configured to transfer the image on the image bearing member to a recording material, a conveyance unit configured to convey the recording material to the transfer unit, a controller configured to form a test sheet by causing a test image to be formed on the image bearing member such that the test image has a predetermined density and causing the test image to be transferred to the recording material, and a determination unit configured to determine a conveyance speed of the recording material such that a density difference between a density of the test image on the test sheet and the predetermined density is less than or equal to a threshold value.

Abstract: An image forming apparatus includes a rotatable image carrier that carries a toner image having a length corresponding to at least a circumferential length of the carrier; an image density detector that detects a density of the image; a potential detector that detects, over at least the circumferential length, a surface potential of the carrier before toner adheres thereto; a first image forming device that adjusts the density with a first factor, and forms an image based on a first condition of the first factor; a second image forming device that adjusts the density with a second factor, and forms an image based on a second condition of the second factor; a first determining device that determines the first condition based on uneven density; and a second determining device that determines the second condition based on uneven density and a potential distribution of the surface potential.

Abstract: In an image forming apparatus, a high-density portion and a low-density portion are arranged close to each other such that a boundary between the high-density portion and the low-density portion intersects with the conveyance direction of a density detection patch. A controller compares, in the conveyance direction, temporal change in the density detection value at a boundary portion shifting from the high-density portion to the low-density portion, with temporal change in the density detection value at a boundary portion shifting from the low-density portion to the high-density portion, and sets a process condition based on a result of the comparison.

Abstract: An image forming unit forms an electrostatic latent image on an image carrier based on image data converted by a conversion unit, and the image is developed by a developing portion using toner. A replenishment control unit controls an amount of the toner with which the developing portion is replenished based on a toner density in the developing portion so that the toner density in the developing portion reaches a target density. A first determination unit determines a target density based on a result of a first measurement image being measured. A correction unit corrects conversion conditions based on a result of measuring a second measurement image and a correction condition. A second determination unit determines the correction condition based on the target density determined by the first determination unit.

Abstract: An image forming apparatus has a detector that includes a toner density sensor arranged on the downstream side of a fixing section. When performing a control to determine an image forming condition of an image forming section based on the detection result of an image-adjusting pattern image obtained by the detector, the temperatures of a plurality of points in the axial direction of the fixing section are detected by a fixing temperature detector. Further, based on the temperature detection values obtained by the fixing temperature detector, a controller sets a detection area of the detector in a place where the fixing temperature is equal to a desired temperature, so that the detector detects the information about the image-adjusting pattern image at such place.

Abstract: A pattern detection sensor includes a light emitting element for specular reflection, a light emitting element for diffuse reflection light, and a light receiving element. When turning on the light emitting element for specular reflection to emit light, a light source switching unit keeps off the light emitting element for diffuse reflection light. When turning on the light emitting element for diffuse reflection light to emit light, the light source switching unit keeps off the light emitting element for specular reflection. An offset detection unit detects a difference between a detection timing by specular reflection light and another detection timing by diffuse reflection light as an offset value (mutual detection error).

Abstract: An optical sensor is disclosed. The optical sensor includes an irradiating system which irradiates a linearly polarized light; a first photodetecting system including a first photodetector which is arranged on an optical path of a light which is specularly reflected from a subject; a second photodetecting system including an optical element which is arranged on an optical path of a light which is diffuse reflected from the subject within an incident face in the subject and which separates a linearly polarized component in a second polarizing direction which is orthogonal to a first polarizing direction and a second photodetector which receives a light separated by the optical element, wherein an angle of taking in the light in the first photodetector and an angle of taking in the light in the second photodetector are mutually different.

Abstract: An image forming apparatus of this invention, when an exposure unit performs exposure, applies, to image data quantized by a first number of bits, compensation data for compensating for unevenness of the exposure intensity occurring on a photosensitive member caused by a lens array used in the exposure unit. This compensation data is obtained by quantizing, by a second number of bits larger than the first number of bits, data corresponding to a change in measurement value obtained by measuring unevenness of exposure occurring on the photosensitive member from a reference value used in the measurement, and requantizing the quantized data by the first number of bits by using sigma-delta modulation.

Abstract: An image forming apparatus includes a control section extracting a color composition of each color ranging from a first to an nth color from input image data, on the color composition of an mth color, the m being 1 to n?1, performing a first and a second gamma corrections correcting a gradation of the color composition respectively based on a gamma curve for the mth color to obtain a first corrected gradation value, and based on a gamma curve for an (m+1)th color to obtain a second corrected gradation value, and interpolating the first and the second corrected gradation values to determine an output value for the color composition, on the color composition of the nth color, correcting a gradation of the color composition based on a gamma curve for the nth color to obtain an output value for the color composition.