Abstract: An image forming apparatus corrects, for uneven density caused by uneven rotation of a rotation speed of a rotation member, and diffuses so as to reduce the uneven density, for a pixel of interest whose density exceeds the upper limit of the output density out of the pixels of the corrected image data, the excess of the density more than the upper limit to a plurality of peripheral pixels while maintaining the center of gravity of the density.

Abstract: An image forming apparatus includes first and second detection units, first to third image forming units, and first to third specifying units. The first and second detection units receive light reflected from first and second regions irradiated with first light and second light having a small range compared with the first light, and detect light-amount signals. The first image forming unit forms first images at first intervals in a first portion passing through the first region. The second image forming unit forms second images having a short length compared with the first images, at second intervals shorter than the first intervals, in a second portion passing through the second region. The third image forming unit forms a third image in the first portion. The first and second specifying units specify misregistration amounts in the first and second images. The third specifying unit specifies density deviation amounts in the third images.

Abstract: An image forming apparatus comprising image forming units, an image bearing member for bearing images, a table indicative of a correspondence relationship between temperature and an amount of a color misregistration. A pattern detection unit detects color registration patterns on the image bearing member. A calculation unit calculates the amount of the color misregistration based on the detection result of the patterns. A color registration adjustment unit has a first mode in which color registration adjustment is performed based on the amount of the color misregistration, and a second mode in which the amount of the color misregistration is predicted based on temperature using the table and the color registration adjustment is performed based on the predicted amount. An updating unit makes the image forming units form the color registration patterns when the temperature reaches a predetermined temperature, and updates the table based on the amount of the color misregistration.

Abstract: If any of a plurality of conditions is satisfied, an image forming apparatus having a plurality of image forming units that form images on an intermediate transfer member in a superimposed manner detects, using a pattern detection sensor, the amount of color misregistration of the images formed by the plurality of image forming units on the intermediate transfer member and corrects the color misregistration of the images formed by the plurality of image forming units in accordance with the amount of color misregistration that is smaller than a color misregistration correction tolerance, which varies depending on the plurality of conditions, and that has been detected by the pattern detection sensor.

Abstract: An image forming apparatus having below arrangements. A plurality of image forming units form a plurality of images which are transferred onto a transfer belt. A detection unit detects a position of the transfer belt in a belt width direction. A position adjusting unit adjusts the position of the transfer belt in the belt width direction according to a detected position. A calibration unit calibrates an adjustment amount for adjusting color registration based on a detected position of patterns formed onto the transfer belt. A registration adjusting unit adjusts image forming positions of the plurality of image forming units based on the set adjustment amount. During formation of the patterns and during detection of the formed patterns a control unit controls not to adjust the position of the transfer belt in the belt width direction according to the detected position of the transfer belt.

Abstract: An image forming apparatus includes a first station including a first photosensitive drum, a second station including a second photosensitive drum, and an intermediate transfer member for receiving the first toner image from the first drum and the second toner image from the second drum sequentially. In addition, a first sensor detects a first index image on the intermediate transfer member, and a second sensor detects a second index image on the second drum. A controller controls a peripheral speed of the second drum, and an executing device executes a test mode using a first test inclined index image and a second test inclined index image. The controller controls image forming conditions for the first and second index images in accordance with outputs of the first and second sensors in the test mode.

Abstract: A Transfer device (10) includes an intermediate transfer belt (41), a plurality of intermediate transfer roller (34A-34D) and a transfer member moving mechanism (20). The transfer member moving mechanism moves the intermediate transfer rollers (34A-34D) between pressing positions causing the intermediate transfer belt (41) to be pressed against respective photoreceptor drums (31A-31D) and separate positions causing the intermediate transfer belt (41) to be separate from the respective photoreceptor drums (31A-31D). The transfer member moving mechanism (20) causes a second pressing position of the intermediate transfer roller for monochrome (34A) in monochromatic image forming to be different from a first pressing position of the intermediate transfer roller for monochrome (34A) in full-color image forming so that an amount of pressing of the intermediate transfer belt (41) by the intermediate transfer roller for monochrome (34A) becomes greater in monochromatic image forming than in full-color image forming.

Abstract: An image formation control section sets a secondary transfer section in the pressed state in the case of execution of a main scanning correction processing as color registration correction, and sets the secondary transfer section in the separated state in the case of execution of a sub-scanning correction processing, an entire lateral magnification correction processing, a partial lateral magnification correction processing, or a skew correction processing, which is the correction of the image position for components other than the main scanning direction as color registration correction so as to prevent the situation where the correction accuracy of the image position with respect to the main scanning direction decreases and to prevent a decrease in print quality due to a residual image of a registration correction processing.

Abstract: A toner-image detecting sensor for detecting a toner image before being transferred onto a recording sheet and a fixed-image detecting sensor for detecting the toner image after being secondarily transferred and fixed on the recording sheet are arranged so that the positions of them in a main scanning corresponding direction are aligned. An image forming apparatus has a first image adjustment mode and a second image adjustment mode. In the first image adjustment mode, image adjustment is made on the basis of only a result of detection by the toner-image detecting sensor without transferring the test pattern onto the recording sheet. In the second image adjustment mode, the test pattern is transferred onto the recording sheet, and image adjustment is made on the basis of both a result of detection by the toner-image detecting sensor and a result of detection by the fixed-image detecting sensor.

Abstract: Electrostatic image graduations inclined by a first angle in a main scanning direction are formed on a photosensitive drum and transferred to an intermediate transfer belt, electrostatic image graduations inclined by a second angle in the main scanning direction are formed on the photosensitive drum and transferred to the intermediate transfer belt so as to overlap with the electrostatic image graduations inclined by the first angle. The electrostatic image graduations inclined by the first angle are detected by a Ch1 conducting wire having a linear conductive member inclined by the first angle in the main scanning direction of the intermediate transfer belt. The electrostatic image graduations inclined by the second angle are detected by a Ch2 conducting wire having a linear conductive member inclined by the second angle in the main scanning direction of the intermediate transfer belt.

Abstract: A first position information formed on an conveyance body is read by an information detecting portion, and a second position information formed on a second image carrier is read by the information detecting portion. A control is made such that a position of an image on the second image carrier matches with a position of an image on the conveyance body from information read by the information detecting portion in transferring the image from the second image carrier to the conveyance body. The information detecting portion is held by a hold member and are disposed at a transfer region.

Abstract: A control portion of an image forming apparatus controls an exposure unit and a developing unit to form misregistration inspecting toner images at both end portions and a center portion of a photoconductive drum and transfers the toner images to an intermediate transfer belt. Then, the control portion detects a misregistration amount of each toner image by misregistration detecting sensors to obtain position information in a main scanning direction per each phase position in which the scanning exposure has been performed on the image carrier. The control portion corrects detection results of the detecting sensors at the both end portions by removing an axial moving amount within a rotation cycle of the photoconductive drum on a basis of a detection result of the misregistration detecting sensor at the center portion.

Abstract: In a registration mark, when toners of plural colors are divided into two groups of a low-reflectance group having a relatively low spectral reflectance and a high-reflectance group having a relatively high spectral reflectance in accordance with high and low levels of spectral reflectances with respect to light emitted by an optical sensor, a toner pattern that gives information of a toner-image formation position of a toner-image forming unit using the toner that belongs to the low-reflectance group includes a first pattern in which the toner that belongs to the high-reflectance group is distributed without a gap in a moving direction of the transferred member, and second patterns formed with the toner used by the toner-image forming unit, the second patterns being arranged on both sides of the first pattern in the moving direction of the transferred member without a gap with respect to the first pattern.

Abstract: An image forming apparatus includes an adjustment sequence controller that causes first to third adjustment processes to be executed. In the first adjustment process, if a second registration mark having reduced calculation errors of shifts of toner-image formation positions as compared with those of a first registration mark is formed in a normal way, the toner-image formation positions are adjusted by using the second registration mark. In the second adjustment process, if the second registration mark is not formed in the normal way, the toner-image formation positions are adjusted by using the first registration mark. In the third adjustment process, if the second registration mark is formed in the normal way after the second adjustment process, the toner-image formation positions are adjusted by using the second registration mark.

Abstract: An image forming apparatus may include an electrophotographic photoreceptor and an intermediate transfer member. An image may be formed by primary transferring a toner image held on a surface of an electrophotographic photoreceptor to an intermediate transfer member, and secondary transferring the toner image from the intermediate transfer member to a transferee material. A dispersive component of surface energy of the electrophotographic photoreceptor and a dispersive component of surface energy of the intermediate transfer member may satisfy a relationship of (the dispersive component of surface energy of the electrophotographic photoreceptor)?(the dispersive component of surface energy of the intermediate transfer member).

Abstract: A computer-based apparatus for preventive maintenance detection for a color printer including a photoreceptor belt (PB) arranged to displace in a process direction, including a memory element for storing a threshold value, computer readable instructions, and registration data for a plurality of markings on a surface of the PB, including for each marking, a respective registration difference, in a lateral direction orthogonal to the process direction, between a respective actual location and a respective original location. The apparatus includes a processor configured to execute the computer readable instructions to: determine that at least one marking from the plurality of markings is out of compliance with the at least one threshold value; and in response to determining that at least one marking from the plurality of markings is out of compliance with the at least one threshold value, transmit a signal, indicating that maintenance is required for the PB, for display.

Abstract: An image forming apparatus includes a detection unit configured to detect a position where a toner image of a color component other than the color component of a misregistration prevention pattern and the toner image of the misregistration prevention pattern overlap each other on a surface of an image carrier; and a control unit configured to control to form the misregistration prevention pattern on the surface of the image carrier except for the overlapping position detected by the detection unit, and not to form the misregistration prevention pattern at the overlapping position on the surface of the image carrier.

Abstract: An image forming apparatus includes a plurality of N image carriers including first through Nth image carriers, a transfer unit including an endless transfer belt, a plurality of M belt supporting members including a plurality of first through Nth nip opposing members contacting the inner surface of the endless transfer belt at positions corresponding to where the plurality of N image carriers contacts the outer surface of the endless transfer belt to form N transfer nips thereat, the first opposing member defining a first supported area of the endless transfer belt, a contact and separation mechanism including a retaining unit to move the first supported area of the endless transfer belt into and out of contact with the first image carrier, and a mark detector to detect a plurality of adjacent marks formed at a predetermined pitch in a circumferential direction of the endless transfer belt.

Abstract: When reading calibration chevrons during mark-on-belt (MOB) sensor timing calibration, cyan portions or legs of printed chevrons are detected in order to determine a timing window offset adjustment. Depending on which of the six cyan legs on the left side of the chevrons are detected, a determination can be made regarding whether the window needs to be started earlier or later. If only the first two cyan legs on the left side of the chevron are detected, then the MOB sensor timing window is beginning (and ending) too early and an appropriate adjustment can be made to cause the timing window to initiate later. If only the last two cyan legs on the left side of the chevron are detected, then the MOB sensor timing window is beginning (and ending) too late, and appropriate adjustment can be made to cause the timing window to initiate earlier.

Abstract: An image forming apparatus and method which reduces time taken for color registration and reflects misregistration of colors in real time to correct color misregistration of prints are provided.

Abstract: An image forming apparatus forms decision registration mark for deciding whether or not a color registration correction for correcting color shifts in the color image carries out on an intermediate transfer belt. The decision registration mark is formed by registering four color registration marks. Color registration sensors detect a detection width of the decision registration mark along a sub scanning direction. A control portion receives the detection width of the decision registration mark and decides whether or not the color registration correction carries out based on whether or not the detection width of the decision mark detected by the detection portion exceeds the period of reference time. When the detection width of the decision mark detected by the detection portion exceeds the period of reference time, the control portion carries out the color registration correction.

Abstract: An image forming apparatus which may include a forming unit configured to form a mark for image adjustment, a conveyor member configured to convey the mark formed by the forming unit and a detecting unit configured to detect the mark conveyed by the conveyor member. Further, the image forming apparatus may include a removing unit configured to remove the mark conveyed by the conveyor member, from the conveyor member; and a control device. According to aspects of the disclosure, after the forming unit has formed a mark for image adjustment, the control device may be configured to determine whether the mark has been removed from the conveyor member and based on the determination of whether the mark has been removed from the conveyor member, begin printing of print data even when the mark has not been completely removed from the conveyor member.

Abstract: A toner consumption calculator includes a plurality of line memories; a recorder that sequentially records image data including a plurality of pixels into the line memories; a skew correction unit that performs skew correction on the image data by sequentially reading the image data from the line memories while controlling read timing; and a counter that sequentially reads the image data from the line memories and counts toner consumption of a target pixel on the basis of light amounts of surrounding pixels of the target pixel.

Abstract: An image forming apparatus includes an image forming device which forms an image on a rotation member, a sensor, and a controller. The controller executes an overlapping pattern detection processing which detects a positional deviation amount using an overlapping pattern including a plurality of overlapping marks with overlapped colorant images of two colors, a non-overlapping pattern detection processing which detects a positional deviation amount using a non-overlapping pattern including a plurality of marks, each having a single color, and an execution processing which executes the overlapping pattern detection processing or the non-overlapping pattern detection processing based on a condition.

Abstract: According to the present invention, to perform double-sided printing or marginless printing, overall image data consonant with an area that includes an area on a print medium and an overrun area are generated based on information concerning the size of the print medium and information concerning the overrun distances. To generate image data, the image data are prepared for both one side of the print medium and the other side of the print medium, so that, relative to the print medium, the position of the image data corresponding to one side matches the position, relative to the print medium, of the image data corresponding to the other side.

Abstract: An image forming apparatus includes an image bearing member, a sensor, a pattern forming section, and a position correction section. The position correction section specifies a first reference position and a second reference position. In a registration correction carried out when the image bearing member is in a time-elapsed state that is a state after the initial state, the position correction section specifies the position of each of the patch images of the respective colors included in the registration correction pattern formed by the pattern forming section at the time of registration correction and corrects based on the first reference position and the second reference position the correction amount to be applied to each image forming position specified in the registration correction currently being carried out.

Abstract: Disclosed is an image forming device that forms toner images on corresponding photosensitive bodies, and performs primary transfers for transferring the toner images on the corresponding photosensitive bodies onto an intermediate transfer body and performs a secondary transfer for transferring the toner images from the intermediate transfer body onto a recording medium. The image forming device includes a position detection unit that detects a position of the intermediate transfer body; a position control unit that controls movement of the intermediate transfer body; a speed determination unit that determines a speed of the intermediate transfer body; and an image forming control unit. The image forming control unit causes the image forming device to form the toner images, to perform primary transfers or to perform a secondary transfer, when the intermediate transfer body is moving at a constant speed.

Abstract: An image forming apparatus includes: a process unit configured to act on a photosensitive member; a detecting unit configured to detect a latent image formed on the photosensitive member; a color misalignment correcting unit configured to perform color misalignment correction based on time information obtained by detecting, by the detecting unit, a detection pattern including a plurality of latent image marks for color misalignment correction; and a storage unit configured to store a weighting coefficient of each latent image mark. The color misalignment correcting unit is further configured to weight the time information by using the corresponding weighting coefficient and perform color misalignment correction.

Abstract: An image forming apparatus includes a color registration error amount calculation unit that calculates a color registration error amount from a first test pattern; a correction information obtaining unit that obtains a correction information for correcting an image on a back surface based on previously obtained contraction information of a printing paper after printing an image on a front surface when printing on both surfaces; and an image data correction unit that corrects the image on the back surface based on the color registration error amount calculated by the color registration error amount and the correction information obtained by the correction information obtaining unit.

Abstract: An image forming apparatus that suppresses occurrence of color shift in images transferred from image bearing members onto an intermediate transfer member. A surface of each of a first photosensitive drum and second photosensitive drums is charged. An exposure device, provided for each photosensitive drum, forms an electrostatic latent image by exposing an associated one of the charged photosensitive drums. A developing device, provided for each photosensitive drum, develops the electrostatic latent image with toner. An intermediate transfer belt friction-drives the photosensitive drums for rotation and has the developed images transferred thereon. Timing for exposing the second photosensitive drums is controlled based on a first surface distance from an exposure light irradiated position to a primary transfer position of the first photosensitive drum, and a second surface distance from an exposure light irradiated position of each second photosensitive drum to a primary transfer position thereof.

Abstract: An image forming apparatus includes the following elements. A transport unit transports a medium on which plural marks are formed at predetermined intervals in the transport direction of the medium. An image forming unit forms an image on the medium. A reading unit is disposed to oppose positions at which the plural marks on the medium are formed so as to read the medium and to generate read information. A detecting unit detects the plural marks from the read information in accordance with predetermined times based on the predetermined intervals of the plural marks. A position adjusting unit adjusts the position of the image to be formed on the medium on the basis of a result of detecting the plural marks. A speed adjusting unit adjusts the transport speed of the medium on the basis of the read information.

Abstract: Test patches are formed such that lengths of the test patches in a rotational direction of the intermediate transfer member are shorter than a length of the intermediate transfer member from a primary transfer portion located in the lowermost stream among the plurality of primary transfer portions to the secondary transfer portion.

Abstract: An image forming apparatus includes a first index forming unit that forms a plurality of first electrostatic latent image indexes at positions adjacent to a toner image to be formed on a recording material in a width direction of a first image bearing member and a second index forming unit forms a plurality of second electrostatic latent image indexes at positions adjacent to a toner image to be formed on the recording material in a width direction of a second image bearing member. A control unit controls operation of at least a second image forming unit so as to maintain a set positional relationship between the first electrostatic latent image indexes transferred to an intermediate transfer member and the second electrostatic latent image indexes based on detection results by first and second detection units.

Abstract: A color registration method of an image forming apparatus, a control method of a host device, an image forming apparatus, a host apparatus, and a computer-readable recording medium are provided. The method includes printing a preset test pattern for color registration, scanning the printed test pattern for color registration, detecting the printed test pattern for color registration from a scan image obtained as a result of the scanning, calculating location error values of respective colors, using the detected test pattern for color registration, and performing the color registration using the calculated location error values of respective colors.

Abstract: An image forming apparatus includes an image forming device to form a toner image according to image data, a density adjustment toner pattern, and a timing adjustment toner pattern on an image bearer, a detector to detect the density adjustment toner pattern and the timing adjustment toner pattern, and an image density adjustment unit to execute image density adjustment based on an amount of toner adhering to the density adjustment toner pattern detected by the toner amount detector. The image density adjustment unit causes the image forming device to form the timing adjustment toner pattern before the density adjustment toner pattern is formed, and the image density adjustment unit adjusts a detection timing of the density adjustment toner pattern based on a detection timing of the timing adjustment toner pattern detected by the toner amount detector.

Abstract: A color image forming apparatus configured to form a combination toner pattern including a second toner image formed downstream in a conveying direction of an intermediate transfer belt on a first toner image and a third toner image formed upstream in the conveying direction of the intermediate transfer belt on the first toner image so that the second and the third toner images cover at least a portion of the first toner image.

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: An image forming apparatus includes a sheet-linear-velocity setting unit, an image-formation-rate changing unit, a detecting unit, and first and second correcting units. When printing is performed with a first sheet linear velocity, the first correcting unit performs misregistration correction according to a result of detection of a misregistration correction pattern image by the detecting unit. When the sheet-linear-velocity setting unit sets a second sheet linear velocity other than the first sheet linear velocity, the second correcting unit corrects an adjustment amount used in the misregistration correction performed by the first correcting unit, according to a ratio between first and second coefficients. The first coefficient indicates a ratio of an actual image formation rate at the first sheet linear velocity to an ideal image formation rate, and the second coefficient indicates a ratio of an actual image formation rate at the second sheet linear velocity to an ideal image formation rate.

Abstract: Aligning image transfer assembly belts using two driven image-bearing belts simultaneously engaged with a driven transport belt. Each image-bearing belt conveys image-forming marking material formed thereon, wherein the transport belt is selectively engageable by the two image-bearing belts. The selective engagement of each image-bearing belt being independent from the other, wherein the two image-bearing belts are remote from one another. The method and apparatus also output signals representing at least one detected lateral positions of an edge of a measured belt using at least one edge sensor. The detected lateral position measured can be achieved by one or two edge sensors, wherein the two edge sensors would be disposed remote from one another along an extent across which the edge of the measured belt moves. Then a skew indication of the simultaneously engaged two image-bearing belts is determined based on a the output edge sensor(s) signals.

Abstract: An image forming apparatus includes image forming sections for respective colors, the image forming sections facing an outer surface of an intermediate transfer belt on an outward path. A transfer roller is provided on a returning path and is movable to a contact position where the transfer roller is pressed against the intermediate transfer belt or to a detachment position where the transfer roller is detached from the intermediate transfer belt. A density sensor is provided for detecting a density of toner image on the intermediate transfer belt. In an image quality adjustment operation, image forming sections form a toner image row on the intermediate transfer belt, and the density sensor measures densities. A length of the toner image row is smaller than a length of the intermediate transfer belt between the endmost photoreceptor drum on the downstream side and the transfer roller.

Abstract: An image forming apparatus configured to form a toner image on a sheet, including: a transfer belt configured to bear and transfer the toner image to the sheet conveyed at given conveying speed; a drive roller configured to drive the transfer belt; a speed detection roller held in contact with the transfer belt and configured to output roller information on rotational speed of the speed detection roller when the speed detection roller rotates as the transfer belt runs; a motor configured to drive the drive roller; a motor speed output portion configured to output motor information on rotational speed of the motor; and a control element configured to control the rotational speed of the motor.

Abstract: An image forming device is provided, which includes an interlocking mechanism that causes a cleaning unit to clean with a cleaning surface thereof a detection surface of a detection sensor for reading each detection pattern formed on an outer surface of a sheet-feeding endless belt, in conjunction with movement of a drawer, which holds a plurality of process cartridges, between an attachment position where a photoconductive drum included in each process cartridge faces an up-facing side of the outer surface of the endless belt and a replacement position where at least one of the process cartridges is outside a main body housing of the image forming device.

Abstract: In an image forming apparatus for making a position deviation correction, a position deviation amount can be accurately calculated by stabilizing the detection result at position deviation detecting and considering an ideal correction amount and an actual correction amount to make the position deviation correction accurately. A forming unit forms a pattern for position deviation detection without making the position correction for less than one pixel by an image position correcting unit, to a pattern formed in the vicinity of a detection region of a detecting unit, and the position deviation amount is calculated by using a value of a position correction which is not made to the pattern for position deviation detection to be formed.

Abstract: An image forming apparatus transfers pattern images for color deviation detection of the respective colors on an endless belt, and corrects color deviation occurring when each image forming unit forms an image on a recording material, in accordance with the amount of color deviation detected by a registration detection sensor. The image forming apparatus forms pattern images of the respective colors on the endless belt at the intervals determined based on the total variation obtained by totaling each variation of the transfer and detection positions of a pattern image of each color on the endless belt from an ideal position. This enables to reduce color deviation detection errors by using pattern images for color deviation detection and improve the accuracy of color deviation correction.

Abstract: An image forming apparatus includes recording heads for ejecting recording liquids of colors onto a recording medium. The apparatus includes a reference-patch forming unit that records a reference patch, the reference patch being formed by overlaying dot array patterns recorded with the recording liquids of different colors, the dot array patterns having no correlation therebetween; a detection-patch-group forming unit that records a detection patch group including detection patches, each of the detection patches being formed by overlaying dot array patterns recorded with the recording liquids of the different colors, the dot array patterns having a same cycle of regular dot array, the detection patches being allocated with different misregistration amounts of the dot array patterns; and a color-misregistration correcting unit that corrects color misregistration based on results of comparison between color tone of the reference patch and color tone of each of the detection patches.

Abstract: The image forming apparatus includes a discharge execution section for forcedly discharging toner from a developing device and forming a toner image on a photosensitive drum, in which a primary transfer roller transfers the toner image formed on the photosensitive drum by the discharge execution section by applying, to a predetermined area part of the toner image, a first transfer bias having a predetermined transfer efficiency with respect to an intermediate transfer belt and applying, to a part excluding the predetermined area part of the toner image, a second transfer bias whose transfer efficiency is at least smaller than the predetermined transfer efficiency of the first transfer bias.

Abstract: An image forming apparatus includes a main body, a plurality of photosensitive drums, a process frame, and a process unit. The plurality of photosensitive drums includes a black photosensitive drum and color photosensitive drums. Black toner is used in the black photosensitive drum. Each of yellow, magenta, and cyan toner is used in one of the color photosensitive drums. The black and color photosensitive drums are arranged in a first direction. Each photosensitive drum has an axis extending in a direction perpendicular to the first direction. The process frame supports the color photosensitive drums in fixed positions and is detachably mounted on the main body. The process frame is inserted in a mounting direction to be mounted on the main body. The process unit is detachably mounted in the process frame and supports the black photosensitive drum.

Abstract: An image formation device comprises imaging units creating toner images in a corresponding color; an intermediate transfer body where the toner images are overlaid in a primary transfer; a secondary transfer unit performing secondary transfers of the overlaid toner images onto a recording sheet; a first misregistration correction unit operable to cause each imaging unit to form a reference pattern, execute a first misalignment reading acquisition process of acquiring a misalignment reading for each pattern, and adjust the imaging units to correct the readings; a storage unit storing the readings; and a second misregistration correction unit operable to cause an imaging unit subset to form reference patterns, execute a second misalignment reading acquisition process of acquiring readings for the subset of patterns and estimating readings in colors for which no pattern is formed from the acquired readings and the stored readings, and adjust the imaging units to correct all readings.

Abstract: An image forming apparatus includes first and second detection units, first to third image forming units, and first to third specifying units. The first and second detection units receive light reflected from first and second regions irradiated with first light and second light having a small range compared with the first light, and detect light-amount signals. The first image forming unit forms first images at first intervals in a first portion passing through the first region. The second image forming unit forms second images having a short length compared with the first images, at second intervals shorter than the first intervals, in a second portion passing through the second region. The third image forming unit forms a third image in the first portion. The first and second specifying units specify misregistration amounts in the first and second images. The third specifying unit specifies density deviation amounts in the third images.

Abstract: A detection device includes an irradiation unit that irradiates a medium with first irradiation light, a first optical system that has a first incident surface and changes the first irradiation light into second irradiation light, a second optical system that has a second incident surface and changes the first irradiation light into third irradiation light, and a light receiving unit that is provided in a traveling direction of reflection light of the second irradiation light and the third irradiation light, which are specularly reflected by the medium, and receives the reflection light of the second irradiation light and the third irradiation light, which are specularly reflected by the medium, so as to detect a positional deviation amount of an image formed on the medium and detect a density deviation amount of the image formed on the medium.