Abstract: An inkjet recording apparatus includes a recording head including a plurality of nozzles for ejecting ink, a conveyor belt that has a plurality of apertures and conveys recording media one by one, a control unit, an ink receiver, and a pipe-shaped ink discharge flow path. The control unit controls drive of the recording head and the conveyor belt to perform flushing, in which the ink is ejected from the nozzle of the recording head to pass through one of the apertures, at a timing different from a timing contributing to image recording. The ink receiver is disposed to face the recording head sandwiching the conveyor belt therebetween, to receive the ink after passing through the aperture when the flushing is performed. The ink discharge flow path is connected to the ink receiver. When the flushing is performed, a predetermined amount of liquid is stored in the ink receiver.

Abstract: An abnormal ejection detection portion detects an abnormal ejection nozzle in a print head based on a read test image read from a sheet with a test pattern formed thereon. When a plurality of abnormal ejection nozzles are detected and the plurality of abnormal ejection nozzles include two consecutive abnormal nozzles corresponding to two consecutive pixels in the read test image, a correction processing portion performs increase correction on an ink ejection amount of consecutive adjacent nozzles adjacent to the two consecutive abnormal nozzles and performs decrease correction on an ink ejection amount of secondary adjacent nozzles adjacent to the consecutive adjacent nozzles.

Abstract: An image forming apparatus includes a recording head, a controller, and a correction processor. The controller determines a nozzle corresponding to an image to be printed, and causes the recording head to eject ink from the nozzle. The correction processor detects an abnormally ejecting nozzle out of the nozzles in the recording head, and designates the abnormally ejecting nozzle as a target nozzle, and performs correction processing based on a status of the target nozzle, to the image. The correction processor also adds the detected abnormally ejecting nozzle to history data, each time a detecting operation is performed, and selects a nozzle included in the history data as an additional target nozzle, out of the nozzles that have not been detected as the abnormally ejecting nozzle, through the current detecting operation, and adds the selected nozzle to the target nozzle.

Abstract: An ink-ejection-malfunction-nozzle detecting unit sets nozzle groups such that each nozzle group includes nozzles with a first interval, prints a first test pattern that includes first bands (including thin lines) corresponding to the nozzle groups, sets nozzle subgroups such that each nozzle subgroup includes nozzles with a second interval in each of the nozzle groups, prints a second test pattern that includes second bands (including thin blank lines) corresponding to the nozzle subgroups such that a correction process is performed for adjacent pixels of the thin blank lines, detects a first band including density defect in a scanned image of the first test pattern, detects a second band not including density defect in a scanned image of the second test pattern, correspondingly to the detected first band, and detects an ink ejection malfunction nozzle on the basis of the thin blank line in the detected second band.

Abstract: In an image forming apparatus, a recording head ejects ink corresponding to an image to be printed, using arranged nozzles. A control unit determines nozzles corresponding to the image to be printed, correspondingly to a position of a print sheet, and causes the recording head to eject ink from the nozzles. A correction processing performs a correction process corresponding to each of ink ejection malfunction positions in the image. Further, the correction processing unit (a) sets the ink ejection malfunction positions as targets of the correction process in advance, and (b) excludes from the targets on the basis of a sheet size of the print sheet an ink ejection malfunction position corresponding to a nozzle that is not used for the print sheet among nozzles corresponding to the plural ink ejection malfunction positions and thereafter performs the correction process for the targets.

Abstract: The inkjet recording apparatus includes a conveyance belt, a conveyance plate, a suction unit, an inkjet head, and a cleaning unit. The conveyance belt has a plurality of through holes. The conveyance plate includes a plurality of through holes formed in bottom portions of the plurality of recessed portions. The suction unit is configured to suck the sheet to the conveyance belt. The inkjet head includes a head main body and a head end portion adjacent to the head main body, and faces an upper surface of the conveyance plate via the conveyance belt. The cleaning unit removes ink adhering to a lower surface of the head main body. A depth of the recessed portion in a facing region facing the head end portion of the conveyance plate is shallower than a depth of the recessed portion in a region other than the facing region.

Abstract: The inkjet recording apparatus includes a conveyance belt, a conveyance plate, a suction unit, an inkjet head, and a cleaning unit. The conveyance belt has a plurality of through holes. The suction unit causes the conveyance belt to suck the sheet. The conveyance plate includes a plurality of through holes formed in bottom portions of the plurality of recessed portions. The inkjet head includes a head main body and a head end portion adjacent to the head main body, and faces an upper surface of the conveyance plate via the conveyance belt. The cleaning unit removes ink adhering to a lower surface of the head main body. A ratio of the recessed portions per unit area in a facing region of the conveyance plate facing the head end portion is smaller than a ratio of the recessed portions per unit area in a region other than the facing region.

Abstract: An image processing apparatus includes a halftone processing unit and a multi-level gradation processing unit. The halftone processing unit is configured to perform a halftone process for a target image and generate a binary image corresponding to the target image. The multi-level gradation processing unit is configured to (a) set a target pixel as a dot pixel in the binary image, (b) determine whether a dot exists on plural first periphery pixels with a predetermined first distance from the target pixel and plural second periphery pixels with a predetermined second distance from the target pixel or not, (c) derive a gradation level of the target pixel among predetermined three or more gradation levels on the basis of a number of dots on the plural first periphery pixels and a number of dots on the plural second periphery pixels and thereby generate a multi-level gradation image.

Abstract: An inkjet recording apparatus includes a recording head including a plurality of nozzles for ejecting ink, a conveyor belt that has a plurality of apertures and conveys recording media one by one, a control unit, an ink receiver, and a pipe-shaped ink discharge flow path. The control unit controls drive of the recording head and the conveyor belt to perform flushing, in which the ink is ejected from the nozzle of the recording head to pass through one of the apertures, at a timing different from a timing contributing to image recording. The ink receiver is disposed to face the recording head sandwiching the conveyor belt therebetween, to receive the ink after passing through the aperture when the flushing is performed. The ink discharge flow path is connected to the ink receiver. When the flushing is performed, a predetermined amount of liquid is stored in the ink receiver.

Abstract: An image processing apparatus includes a halftone processing unit and a multi-level gradation processing unit. The halftone processing unit is configured to perform a halftone process for a target image and generate a binary image corresponding to the target image. The multi-level gradation processing unit is configured to (a) set a target pixel as a dot pixel in the binary image, (b) determine whether a dot exists on plural first periphery pixels with a predetermined first distance from the target pixel and plural second periphery pixels with a predetermined second distance from the target pixel or not, (c) derive a gradation level of the target pixel among predetermined three or more gradation levels on the basis of a number of dots on the plural first periphery pixels and a number of dots on the plural second periphery pixels and thereby generate a multi-level gradation image.

Abstract: An ink jet recording apparatus includes a recording head, a wiper member, a cleaning liquid supply device, and a controller. The recording head includes an ink ejection surface having an ink ejection port from which ink is ejected. The cleaning liquid supply device includes a cleaning liquid supply surface having a cleaning liquid supply port from which cleaning liquid for wiping the ink ejection surface with the wiper member is supplied, and is located upstream of the ink ejection surface in a wiping direction. The controller controls a cleaning operation including squeezing out the cleaning liquid containing bubbles from the cleaning liquid supply port, and moving the wiper member carrying the cleaning liquid containing bubbles, in the wiping direction from a movement start position to an end position ahead of the ink ejection surface.

Abstract: An inkjet recording apparatus includes a recording head, a wiper member, a cleaning liquid supply device, a cleaning liquid flow path, and a controller. The cleaning liquid flow path includes a vertical tubular member connected to the cleaning liquid supply device and extending upward, and a horizontal tubular member connected to an upper end of the vertical tubular member and extending in a horizontal direction. The controller extrudes a cleaning liquid in at least a part of the cleaning liquid flow path from a cleaning liquid supply port before control of a cleaning operation for wiping an ink ejection surface of the recording head, thereby performing control of an air bubble release operation of the cleaning liquid flow path.

Abstract: The inkjet recording apparatus includes a conveyance belt, a conveyance plate, a suction unit, an inkjet head, and a cleaning unit. The conveyance belt has a plurality of through holes. The suction unit causes the conveyance belt to suck the sheet. The conveyance plate includes a plurality of through holes formed in bottom portions of the plurality of recessed portions. The inkjet head includes a head main body and a head end portion adjacent to the head main body, and faces an upper surface of the conveyance plate via the conveyance belt. The cleaning unit removes ink adhering to a lower surface of the head main body. A ratio of the recessed portions per unit area in a facing region of the conveyance plate facing the head end portion is smaller than a ratio of the recessed portions per unit area in a region other than the facing region.

Abstract: The inkjet recording apparatus includes a conveyance belt, a conveyance plate, a suction unit, an inkjet head, and a cleaning unit. The conveyance belt has a plurality of through holes. The conveyance plate includes a plurality of through holes formed in bottom portions of the plurality of recessed portions. The suction unit is configured to suck the sheet to the conveyance belt. The inkjet head includes a head main body and a head end portion adjacent to the head main body, and faces an upper surface of the conveyance plate via the conveyance belt. The cleaning unit removes ink adhering to a lower surface of the head main body. A depth of the recessed portion in a facing region facing the head end portion of the conveyance plate is shallower than a depth of the recessed portion in a region other than the facing region.

Abstract: An inkjet recording apparatus includes a recording head, a wiper member, a cleaning liquid supply device, a cleaning liquid flow path, and a controller. The cleaning liquid flow path includes a vertical tubular member connected to the cleaning liquid supply device and extending upward, and a horizontal tubular member connected to an upper end of the vertical tubular member and extending in a horizontal direction. The controller extrudes a cleaning liquid in at least a part of the cleaning liquid flow path from a cleaning liquid supply port before control of a cleaning operation for wiping an ink ejection surface of the recording head, thereby performing control of an air bubble release operation of the cleaning liquid flow path.

Abstract: An ink jet recording apparatus includes a recording head, a wiper member, a cleaning liquid supply device, and a controller. The recording head includes an ink ejection surface having an ink ejection port from which ink is ejected. The cleaning liquid supply device includes a cleaning liquid supply surface having a cleaning liquid supply port from which cleaning liquid for wiping the ink ejection surface with the wiper member is supplied, and is located upstream of the ink ejection surface in a wiping direction. The controller controls a cleaning operation including squeezing out the cleaning liquid containing bubbles from the cleaning liquid supply port, and moving the wiper member carrying the cleaning liquid containing bubbles, in the wiping direction from a movement start position to an end position ahead of the ink ejection surface.

Abstract: An inkjet recording apparatus includes a sheet conveying unit, a storage unit, a line head, and a control unit. The line head includes an upstream-side head and a downstream-side head. The upstream-side and downstream-side heads are fitted to have overlapping portions in which a plurality of nozzles arranged in respective end portions of the heads overlap as seen from the sub scanning direction. When an adjustment chart is printed, the control unit makes the nozzles in the overlapping portion of the upstream-side head print a first line. The control unit makes the nozzles in the overlapping portion of the downstream-side head print a second line.

Abstract: An inkjet recording apparatus includes a sheet conveying unit, a storage unit, a line head, and a control unit. The line head includes an upstream-side head and a downstream-side head. The upstream-side and downstream-side heads are fitted to have overlapping portions in which a plurality of nozzles arranged in respective end portions of the heads overlap as seen from the sub scanning direction. When an adjustment chart is printed, the control unit makes the nozzles in the overlapping portion of the upstream-side head print a first line. The control unit makes the nozzles in the overlapping portion of the downstream-side head print a second line.

Abstract: A differential correction data generating unit measures two density characteristics at a reference linear velocity and another linear velocity from scanned images of two test charts printed at the reference linear velocity and the another linear velocity, and generates differential correction data as a difference between correction amounts for the measured two density characteristics. A correction amount adjusting unit measures a density characteristic at the reference linear velocity from an adjustment toner pattern formed on an intermediate transfer member, and thereby adjusts a correction amount for the density characteristic at the reference linear velocity. A density characteristic of a printing image is corrected, (a) for the reference linear velocity, on the basis of the correction amount at the reference linear velocity, and (b) for the another linear velocity, on the basis of the correction amount at the reference linear velocity and the differential correction data.

Abstract: A differential correction data generating unit measures two density characteristics at a reference linear velocity and another linear velocity from scanned images of two test charts printed at the reference linear velocity and the another linear velocity, and generates differential correction data as a difference between correction amounts for the measured two density characteristics. A correction amount adjusting unit measures a density characteristic at the reference linear velocity from an adjustment toner pattern formed on an intermediate transfer member, and thereby adjusts a correction amount for the density characteristic at the reference linear velocity. A density characteristic of a printing image is corrected, (a) for the reference linear velocity, on the basis of the correction amount at the reference linear velocity, and (b) for the another linear velocity, on the basis of the correction amount at the reference linear velocity and the differential correction data.