Abstract: An image forming apparatus includes: a carrier; an image forming unit configured to form an image on the carrier using colorant, the image including a pattern; a pattern sensor configured to detect the pattern formed on the carrier; a cleaner configured to perform cleaning of the carrier; and a residue sensor configured to perform detection of residual colorant remaining on the carrier after the cleaner performs the cleaning of the carrier. A detection condition for the residue sensor to perform the detection of the residual colorant is more suitable for detecting colorant than the detection condition for the pattern sensor to detect the pattern.

Abstract: An image forming apparatus includes: a forming unit configured to form a mark on a carrier; a light emitting unit configured to emit light toward a surface of the carrier; a light receiving unit configured to receive reflected light from the surface of the carrier and from the mark and configured to output a light reception signal corresponding to a amount of the received reflected light; a detecting unit configured to detect a position of the mark on the carrier on a basis of a signal wave contained in the light reception signal; and a modification unit configured to modify the detected position of the mark by a modification amount corresponding to a difference in a waveform of the signal wave corresponding to the mark so as to reduce an error between the detected position and an actual position.

Abstract: An image forming apparatus including an image carrier, a plurality of forming devices, a detecting device configured to perform a steady-deviation detection for detecting steady positional deviation and a varying-deviation detection for detecting varying positional deviation having a cycle, and a correcting device configured to perform a steady-deviation correction for correcting the steady positional deviation and a varying-deviation correction for correcting the varying positional deviation. The detecting device forms, during the steady-deviation detection, a steady-deviation detection pattern in a state where the varying deviation correction is selectively disabled. The steady-deviation detection pattern has a plurality of measuring points arranged in a longitudinal direction. The detecting device, during the steady-deviation detection, measures positional deviation amount at each measuring point, and detects the steady positional deviation based on the measurement result.

Abstract: An image forming apparatus includes a plurality of forming devices, a measuring device and a correcting device. In execution of a steady-deviation detection, the correcting device controls the forming devices to form a first pattern and detects a steady deviation amount of the image forming position on a basis of a measurement result of the first pattern. In execution of a varying-deviation detection, the correcting device controls at least one of the forming devices to form a second pattern and detects a varying deviation amount of the image forming position having a cycle on a basis of a measurement result of the second pattern. The correcting device determines necessity of executing the other one of the steady-deviation detection and the varying-deviation detection on the basis of the measurement result in the one of the steady-deviation detection and the varying-deviation detection.

Abstract: An image-forming device includes an image-forming unit, a sensor, a screening unit, an excluding unit, and a determining unit. The image-forming unit forms a plurality of marks on an object. The sensor detects a light reflected on the object, the reflected light including a plurality of waveforms. The screening unit screens the plurality of waveforms into a plurality of mark waveforms corresponding to the plurality of marks respectively and a plurality of noise waveforms other than the plurality of mark waveforms. The excluding unit excludes a mark waveform adjacent to the noise waveform from the plurality of mark waveforms. The determining unit determines a position of each mark based on the plurality of mark waveforms from which the mark waveform adjacent to the noise waveform is excluded.

Abstract: An image-forming device includes an image-forming unit, a sensor, a calculating unit, and an extracting unit. The image-forming unit forms a plurality of marks on an object. The sensor detects a light reflected on the object, the reflected light including a plurality of waveforms. The calculating unit calculates a first value of each waveform in a predetermined evaluation index, a second value of a basic waveform corresponding to an ideal mark in the predetermined evaluation index, and a matching rate of each waveform with the basic waveform based on both each first value and the second value. The extracting unit extracts, from the plurality of waveforms, waveforms whose matching rates satisfy a predetermined condition.

Abstract: An image forming apparatus including an outer frame, a photosensitive unit, a drum drive gear, a first positioning portion, and a second positioning portion. The photosensitive unit includes a plurality of photosensitive drums, a first supporting shaft, a second supporting shaft, and a drum gear. Each of the plurality of photosensitive drums has an axis extending in a first direction. The plurality of photosensitive drums is juxtaposed in a second direction perpendicular to the first direction. A position of the first supporting shaft and the second supporting shaft provided on one of the plurality of photosensitive drums in the second direction with respect to the outer frame is determined by contacting the first supporting shaft and the second supporting shaft to the first positioning portion.

Abstract: A patch mark-forming unit forms a first patch mark at a first density on a surface. A light emitting unit emits an incident light onto the surface moving. The incident light reflected by the surface is divided into a mirror-reflected light and a diffusion-reflected light on the surface. A first detecting unit detects an amount of the diffusion-reflected light. The patch mark forming unit reforms a second patch mark at a second density weaker than the first density it the amount detected by the first detecting unit is larger than a threshold. A second detecting unit detects an amount of the mirror-reflected light reflected by the surface on which the second patch mark has been reformed. A position calculating unit calculates, based on the amount detected by the second detecting unit, a position on the surface at which an image should be formed. An image-forming unit forms an image at the position.

Abstract: An image forming apparatus includes an image carrier unit, a unit containing portion, driving units, driving sources, and a phase change matching unit. The image carrier unit integrally has image carriers that respectively carry images, and respectively have rotational shafts. The unit containing portion removably contains the image carrier unit. Each of the driving units includes at least one driving gear, and transmits driving force by the driving gear to the rotational shaft of one of the image carriers that corresponds thereto. The driving sources apply the driving force to the driving gears of the driving units. The phase change matching unit matches phase changes in the driving gears of the driving units when no image is formed.

Abstract: A controlling section controls an image forming section to form a calibration pattern on an object. The calibration pattern includes a plurality of first patterns and a plurality of second patterns. Each of the first patterns includes at least one pair of marks. Each of the at least one pair of marks has different colors and overlaps with each other in a first direction. The first patterns have different degrees of overlapping from each other. Each of the second patterns is formed between one of the first patterns and another one of the first patterns in the moving direction. The detecting section detects the first and second patterns formed on the object. The correcting section corrects the image forming position in the first direction based on detection results of the first patterns, and corrects the image forming position in a second direction based on detection results of the second patterns.

Abstract: An image forming apparatus includes an image forming section, a controlling section, a detecting section, and a correcting section. The image forming section forms an image on an object. The controlling section controls the image forming section to form a calibration pattern on the object. The calibration pattern includes a plurality of marks in a first group and a plurality of marks in a second group. The plurality of marks in each of the first group and the second group is arranged in a first direction over a predetermined range. The plurality of marks in each of the first group and the second group includes first marks and second marks. The first mark in the first group corresponds to the second mark in the second group in a second direction different from the first direction in at least part of the predetermined range. The first mark in the second group corresponds to the second mark in the first group in the second direction in at least part of the predetermined range.

Abstract: A controlling section controls an image forming section to form a calibration pattern on an object. The calibration pattern includes a plurality of marks in first and second groups. The marks in the second group are formed at a different position in the second direction from the marks in the first group. The marks in each of the first and second groups are arranged in the first direction over a predetermined range on the object. Each mark has shape and color. The detecting section detects the calibration pattern formed on the object, thereby obtaining detection results. The correcting section corrects, based on the detection results, an image forming position at which the image forming section forms an image. The marks belonging to different groups and having a same color are formed at different positions with respect to the first direction in at least part of the predetermined range.

Abstract: An image forming apparatus is described. The image forming apparatus may include a main body casing, a reference shaft, a photosensitive unit, developing units and a pressing member. The photosensitive unit is detachably attachable to the main body casing along an attachment/detachment direction, holds photosensitive members, and has an engaging portion. The developing unit has a developing agent carrier. The pressing member is configured to linearly move along the attachment/detachment direction between a press position for pressing the developing unit to press the developing agent carrier into contact with the photosensitive member and a press releasing position for releasing this press contact. The pressing member urges the developing unit in a direction in which the engaging portion comes into engagement with the reference shaft in a process of moving from the press releasing position to the press position.

Abstract: A light receiving portion is configured to receive a light that varies with time while a mark formed on an object moves across a detection area. The position of the mark on the object is determined based on comparison of a time-varying level of said light with at least one threshold during movement of said mark on said object across said detection area. The determined position of the mark is corrected by a correction value into a corrected mark position. The correction value is set to a higher value, if the time-varying light level exceeds the threshold or falls below the threshold with a smaller slope while the mark moves across the detection area. An image forming position is adjusted based on the corrected mark position.

Abstract: A matched ideal waveform is extracted from a plurality of ideal waveforms based on degree of coincidence with a light sensitive waveform obtained by a light receiving portion. The plurality of ideal waveforms differ from one another in phase. The displacement amount of an image to be formed of an adjustive color from an image to be formed of a reference color is determined based on the extracted matched ideal waveform.

Abstract: An image-forming device includes an image bearing member, a data providing unit, an image-forming unit, a detecting unit, a first calculating unit, a determining unit, and a second calculating unit. The image bearing member has a surface moving at a surface speed. The data providing unit provides pattern data indicative of a target test pattern to be formed on a target position of the surface in response to a test instruction. The image-forming unit forms an actual test pattern on an actual position of the surface in accordance with the pattern data provided from the data providing unit, and configure to form an image in response to an image-forming instruction. The detecting unit detects the actual position. The first calculating unit calculates a deviation of the actual position from the target position. The determining unit performs a first determination of whether the surface speed when the data providing unit receives the test instruction is stable or unstable.

Abstract: An image-forming device includes 1st to Mth photosensitive drums, a forming unit, an image-carrying member, a detecting unit, and a calibrating unit. The 1st to Mth photosensitive drums are arrayed in numeric order in a first direction. Each of the photosensitive drums is rotatable and has a circumferential length D. M is an integer no less than 1. The forming unit forms a registration mark on each of the photosensitive drums. Each of the registration marks formed on each of the photosensitive drums has a color different from one another. The image-carrying member extends in the first direction. The registration marks formed on the photosensitive drums are transferred onto the image-carrying member in the numeric order. The registration marks transferred onto the image-carrying member are arrayed in the first direction. Neighboring registration marks are spaced by a distance L in the first direction. The detecting unit detects positions of the registration marks transferred onto the image-carrying member.

Abstract: During a first operation, at least one of a first pattern and a second pattern is formed on a first area of an image carrier, and at least the other pattern is formed on a second area of the image carrier. The first area corresponds to a half of the image carrier, while the second area corresponds to the remaining half of the image carrier. During a second operation, a second pattern is formed on an area of the image carrier where a first pattern is formed during the first operation, and a first pattern is formed on an area of the image carrier where a second pattern is formed during the first operation.

Abstract: The pattern data generating unit generates pattern data indicative of a pattern of a plurality of marks including a plurality of first marks each having a first color and a plurality of second marks each having a second color so that a first target-total is equal to a second target-total. The first target-total is a total of deviations of first target-positions from a reference position in a predetermined direction. The second target-total is a total of deviations of second target-positions from the reference position in the predetermined direction. The controlling unit controls the image-forming unit to calibrate the second target-positions based on the offset of a second actual-total from a first actual-total.

Abstract: An image-forming device includes a pattern data generating unit, an image-forming unit and a detecting unit. The pattern data generating unit generates pattern data indicative of a pattern of a plurality of marks. The plurality of marks includes a first mark having a first color, a first light reflectance, a first width in a predetermined direction and a first dot density and a second mark having a second color, a second light reflectance, a second width in the predetermined direction and a second dot density. A difference between a target light reflectance and the first light reflectance is greater than a difference between a target light reflectance and the second light reflectance. At least one of the first mark width and the first dot density is smaller and lower than the second mark width and the second dot density. The image-forming unit forms the plurality of marks at positions on a target having the target light reflectance, based on the pattern data.