Abstract: In one embodiment, image reading apparatuses 100a and 100b start reading an original image after a reading start time Ta has elapsed since detecting the transport timing of an original G on the upstream side in a transport direction Y1 relative to an original reading position R1, adjust the reading start time Ta based on a reading timing adjustment time T1a from when the transport timing of an adjustment sheet P is detected until when original reading portions 200a and 200b read a position considered to be a leading edge P? in a first mark Q1 on the adjustment sheet P, and correct the reading start timing of the original G based on a leading edge reading error correction time T2a stored in advance.

Abstract: In an image forming apparatus, a computing unit computes phase shift amounts A(i) for every correction relative phase angle ?(j) based on an amplitude B of a reference compressional wave ?a, an amplitude C(i) of a detection compressional wave ?(i), and a relative phase angle ?(i). A setting unit specifies the phase shift amounts A(i), and sets a correction relative phase angle ?(j) corresponding to the specified phase shift amounts A(i). A correction unit corrects, based on the correction relative phase angle ?(j) set by the setting unit, a relative phase shift between a periodic variation in the circumferential speed of a first image bearing member and a periodic variation in the circumferential speed of a second group image bearing member by operationally controlling at least one of first and second drive units.

Abstract: An image forming apparatus includes an image forming portion that forms an image on a recording sheet, a transport path that transports the recording sheet with the image formed thereon by the image forming portion, a coating portion that performs a coating process that forms a coating film on the recording sheet that is being transported on the transport path, and a reading portion that reads a calibration chart on the recording sheet that is being transported on the transport path. The coating portion is disposed on the upstream side in a recording sheet transport direction of the reading portion on the transport path, a calibration process is performed for an image formed by the image forming portion, and the calibration chart is formed on the recording sheet by the image forming portion in order to perform the calibration process.

Abstract: An image forming apparatus includes a coating portion configured to perform a coating process that forms a coating film on a recording sheet with an image formed thereon, a main transport path configured to transport the recording sheet with the image formed thereon and to have a branching portion formed thereon, and a sub transport path configured to be once branched from the main transport path at the branching portion and to be returned to the main transport path again. The coating portion is disposed on the sub transport path.

Abstract: According to an embodiment of the present invention, an image forming apparatus includes a toner image carrier that carries a toner image, a toner image detection sensor that detects a reference toner image on the toner image carrier, a temperature sensor that detects a temperature in the apparatus, and storage section for storing a correlation between each temperature and a drive value for the toner image detection sensor, in which calibration of the toner image detection sensor is performed by acquiring a corresponding drive value from the storage section based on the temperature measured by the temperature sensor and driving the toner image detection sensor at the acquired drive value.

Abstract: According to a color image forming apparatus, a plurality of detection patterns respectively corresponding to a plurality of colors are formed from a plurality of photosensitive body units respectively corresponding to the plurality of colors onto a transfer member in a sub-scanning direction of the transfer member, intervals between detection patterns adjacent to each other in the sub-scanning direction among the plurality of formed detection patterns are detected, and adjustment of color misalignment is performed based on the detected intervals. The plurality of detection patterns have the same size and the same shape. In this color image forming apparatus, the adjustment of color misalignment is performed using at least two types of data of detection images having different intervals as data of detection images including the plurality of detection patterns.

Abstract: In one embodiment, the present invention provides an image forming apparatus that forms a plurality of images using a plurality of image carriers respectively corresponding to the images and stacks those images, the apparatus having a first group to which at least one image carrier among the plurality of image carriers belongs, a second group to which at least one image carrier among the remaining image carriers belongs, and a single detection sensor that detects a first detection information for identifying a rotation timing of the first group image carrier and also detects a second detection information for identifying a rotation timing of the second group image carrier.

Abstract: In a registration step, the temperature near a polygon mirror (83) is detected by a first temperature sensor (85), and the internal ambient temperature of an image forming apparatus (1) is detected by a second temperature sensor (86). Also, a registration adjustment value of each color is determined and stored in a memory (75). In a printing step, the registration adjustment value (A) of each color determined in the registration step is corrected based on a change in the temperature near the polygon mirror (83) and a change in the internal ambient temperature of the image forming apparatus (1). Furthermore, the write timing of an electrostatic latent image onto each photosensitive drum (13) by an optical scanning device (11) is controlled. Then, the position of the electrostatic latent image on each photosensitive drum (13) is shifted by an amount corresponding to the corrected registration adjustment value.

Abstract: An LD switch is turned ON to output image data outputted from an image processing section to a laser diode, and to irradiate a laser light to a photosensitive drum. The number of pixel dots included in the image data outputted from the image processing section is computed by line basis to detect an image density based on the total sum of the pixel dots of each color at a timing when the image data of Nth line is outputted from the image processing section. The detected image density is compared with a threshold value to turn OFF the LD switch at a timing when the image data of (N+?)th line is outputted when the image density is greater than the threshold value. This suppresses a variation in a rear-end-void length due to sheet slippage.

Abstract: The image forming apparatus includes: a paper feed unit; a print unit; a registration roller; a sheet leading end sensor provided downstream, in a transport direction of the recording paper, of the registration roller; a time measuring unit for measuring a time from a start point of transportation of the recording paper by the registration roller to a point of detection of the leading end of the recording paper by the sheet leading end sensor; a memory unit for storing a reference image forming time and a reference time; a print control unit; and an arithmetic unit for obtaining a difference between the reference time and the time detected by the time measuring unit. The print control unit adjusts the length of the image forming period in accordance with the adjusted image forming time determined based on the difference obtained by the arithmetic unit and the reference image forming time.

Abstract: To provide an image forming apparatus which can prevent malfunction of the open/close control of a shutter due to erroneous detection of the toner on the transfer belt when the opening and closing of the shutter is detected from the output from an optical sensor. The separation/contact assembly for moving a cleaning member into and out of contact includes an arm rotationally supported on a pivot, an abutment part fixed to the body frame so as to limit the rotation of the arm and a spring for pressing the arm in the clockwise direction. The cleaning member is attached at the distal end of the arm. The cleaning member cleans the transfer belt surface when the shutter is closed, so that the cleaned transfer belt surface can be always detected when the shutter is open.

Abstract: A color image forming apparatus including a test pattern formation portion that forms test patterns of a plurality of colors in an image formation area in which images of the plurality of colors are formed on an image carrier and in an image non-formation area outside the image formation area on the image carrier, a detection portion that detects a shift of each of the test patterns of the plurality of colors formed in the image formation area and a shift of each of the test patterns of the plurality of colors formed in the image non-formation area, a computing portion that obtains, for each color, an offset value indicating an offset between the shift of the test pattern in the image non-formation area and the shift of the test pattern in the image formation area, and a storage portion that stores the offset value for each color.

Abstract: In an embodiment of the present invention, an image forming apparatus includes a transfer belt that primarily transfers a toner image formed on a photosensitive drum; a secondary transfer unit including a transfer mechanism portion that secondarily transfers the primarily transferred toner image to a paper; an optical sensor that detects a reference toner image on the transfer belt; and a shutter that protects a detection face of the optical sensor, wherein a separation/contact mechanism portion disposed so as to be brought into contact with both of the shutter and the secondary transfer unit is provided, and the separation/contact mechanism portion allows the shutter to move so as to open and allows the secondary transfer unit to move so as to separate from the transfer belt when the reference toner image is detected by the optical sensor, and allows the shutter to move so as to separate from the transfer belt when the secondary transfer unit is drawn out from an apparatus main body.

Abstract: There is provided an image forming apparatus that includes couplings for photoreceptor drums, couplings for waste toner transporting screws, and couplings for developing rollers, that transmit driving force to each of a plurality of driving shafts for driving a process portion that performs image formation by an electrophotographic method, and a plurality of coupling attaching/detaching members for attaching/detaching the plurality of coupling members, so as to drive the process portion. In the image forming apparatus, the plurality of coupling attaching/detaching members are provided so as to be movable independently, and the image forming apparatus includes a coupling attaching/detaching member driving mechanism that operates the coupling attaching/detaching members in association with each other.

Abstract: In one embodiment, an image forming apparatus (100) is provided with a resin frame (300) made of resin and an image forming unit (200). The image forming apparatus further includes a first duct (410) that allows air to flow on one side of the image forming unit (200), a second duct (420) that allows air to flow on the other side, and a third duct (430) that allows air to flow between the first duct and the second duct. The resin frame (300) has a first duct portion (311) that constitutes at least a portion of the first duct (410), and a second duct portion (321) that constitutes at least a portion of the second duct (420).

Abstract: An image forming apparatus of the present invention includes a resin frame composed of a resin and an image forming unit that is removably inserted in the resin frame. The resin frame includes a base having a supporting surface that supports the image forming unit, a guide portion that extends in the base in an insertion direction in which the image forming unit is inserted along the supporting surface and that guides the image forming unit in the insertion direction while limiting movement of the image forming unit in an orthogonal direction that is orthogonal to the insertion direction, and a side plate portion that is provided at a peripheral edge of the base so as to extend in a direction perpendicular to the supporting surface, the base, the guide portion, and the side plate portion being integrally molded from a resin.

Abstract: An image forming apparatus provided with a resin frame made of a resin, an image forming unit and a fixing unit includes a duct for allowing air to flow between the image forming unit and the fixing unit. The resin frame includes a main frame to which the image forming unit is attached, and a fixing unit attachment frame that is separate from the main frame and to which the fixing unit is attached, and the fixing unit attachment frame has a duct portion that constitutes at least one part of the duct.

Abstract: An image forming apparatus includes a controller for detecting the opening and closing of a shutter from the output from an optical sensor and controlling the opening and closing operation of the shutter based on the detected result. The controller determines that if the optical sensor is turned “ON” within a predetermined period of time from when the shutter begins opening, the operation of the shutter from the closed state to the open state is correctly detected. When no reflected light is detected by the optical sensor even after a predetermined time has elapsed, the controller determines that an anomaly has occurred and closes the shutter and repeat another detecting process.

Abstract: In an image forming apparatus, a computing unit computes phase shift amounts A(i) for every correction relative phase angle ?(j) based on an amplitude B of a reference compressional wave ?a, an amplitude C(i) of a detection compressional wave ?(i), and a relative phase angle ?(i). A setting unit specifies the phase shift amounts A(i), and sets a correction relative phase angle ?(j) corresponding to the specified phase shift amounts A(i). A correction unit corrects, based on the correction relative phase angle ?(j) set by the setting unit, a relative phase shift between a periodic variation in the circumferential speed of a first image bearing member and a periodic variation in the circumferential speed of a second group image bearing member by operationally controlling at least one of first and second drive units.

Abstract: Multiple photoconductive drums on which images with different color components are formed respectively are rotated using individual motors, multiple adjustment images are formed at a predetermined interval along the cycle length of one rotation of each photoconductive drum, the reference phases for the rotation of the respective photoconductive drums are determined based on the maximum portions of the divergences between the predetermined interval and the detection interval of each adjustment image, and the individual motors are controlled so that the respective reference phases determined are aligned. The image forming region corresponding to the cycle length of one rotation of the photoconductive drum is divided into four or more even-numbered regions, the divergence amount of each region is calculated, and the maximum portions of the divergences are determined based on the difference between the divergence amounts of the divided regions being away from each other by a half cycle length.