A discharge position adjusting method includes: moving a first nozzle row and a second nozzle row in scanning directions, each of the first and second nozzle rows having a plurality of nozzles that eject liquid droplets, the first and second nozzle rows being disposed at different locations in a predetermined direction, the scanning directions intersecting the predetermined direction; forming a first image by ejecting liquid droplets from the first nozzle row, and forming a second image by ejecting liquid droplets from the second nozzle row; and adjusting positions at which liquid droplets are to be placed by using the first and second images. The first and second images are created during the moving of the first and second nozzle rows.

A method is provided that is implemented on a control device connected with an inkjet printer, which includes an inkjet head having an ink discharging surface, a head scanning unit reciprocating the inkjet head relative to a recording sheet along a scanning direction parallel to the ink discharging surface, and a wave shape generating mechanism deforming the recording sheet in a predetermined wave shape that has tops of portions protruding in a first direction toward the ink discharging surface and bottoms of portions recessed in a second direction opposite to the first direction alternately arranged along the scanning direction, the method including acquiring gap information related to a gap between the ink discharging surface and each individual one of the tops and the bottoms on the recording sheet, and determining whether the gap information acquired for each individual one of the tops and the bottoms is abnormal.

Print head for black material is arranged such that the black material is to be ejected later than cyan, magenta, and yellow materials on both of forward and backward strokes, and the print heads for the cyan, magenta, and yellow materials are arranged in tandem in a main-scanning direction. The first processing unit converts input image data into CMY image data and then performs black generation and undercolor removal on the CMY image data, to obtain CMYK image data. The second processing unit converts CMY image data excluding K image data from the CMYK image data into image data for use in printing in the backward direction. The on/off switching unit switches between causing and not causing the second processing unit to covert the CMY image data depending on which one of printing in the forward stroke and printing in the backward stroke is to be performed.

An image forming apparatus includes an image forming unit having at least two nozzle lines each having multiple nozzles to discharge different color droplets; a carriage that carries the image forming unit and is configured to reciprocate in the moving direction crossing an arrangement direction of the nozzles; and a control device to control dual-directional printing to form an image using the at least two nozzle lines in an outward and a return of the carriage. The control device executes color difference handling print control for discharging the different color droplets by using, of each of the nozzles in the at least two nozzle lines, the nozzles located at different positions in the arrangement direction of the nozzles while not overlapping in the moving direction of the carriage.

A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

A liquid discharge apparatus includes a support portion that supports a sheet that is transported and a discharge unit that includes a carriage that is freely movable in scanning directions that intersect with a transport direction of the sheet and a liquid discharge head that is mounted on the carriage and that discharges ink to the sheet. End portions of the discharge unit in the scanning directions are provided with a plurality of ribs that are protruded along the scanning directions and that are provided so as to be juxtaposed with intervals in the transport direction. The ribs press a bend of the sheet toward the support portion as the carriage moves along the scanning directions.

In an inkjet printer, a controller is configured to calculate, during movement of a carriage in a scanning direction, a signal level difference between a first detection signal in a mountain peak zone including an assumed mountain peak position and the first detection signal in a valley bottom zone including an assumed valley bottom position identified, based on information stored in a storage, and alternately execute, during the movement of the carriage, an ejection process of ejecting ink drops, and a conveying process of conveying the sheet by a predetermined line feed width. In the printing process, the printing head and the conveyor are driven according to a first condition when the signal level difference is equal to or larger than a threshold value, while driven according to a second condition when the signal level difference is less than the threshold value.

A recording apparatus includes an ejecting unit which can eject first ink for image forming and colorless second ink onto a recording medium; and a control unit which can control ejecting operations of the first ink and the second ink in the ejecting unit, in which the control unit performs a plurality of ejecting operations of the first ink with respect to one ejecting operation of the second ink, so that at least a part of a landing position of the second ink and a landing position of the first ink overlap on the recording medium.

Wherein, in the first dither mask, when the first space is cut by the first plane, a plurality of threshold values in the first plane has a blue noise characteristic in the spatial frequency domain, and when the first space is cut by a second plane extending in a direction different from that of the first plane, a plurality of threshold values in the second plane has a blue noise characteristic in the spatial frequency domain.

A printing apparatus includes a printing head including a nozzle configured to discharge ink, and a control unit configured to control the printing head to print a test pattern on a printing medium, for inspecting a state of ink discharge by the nozzle. The test pattern includes a pattern element formed by a plurality of dots of the ink, and the control unit causes the printing head to print the test pattern where a number of the dots forming the pattern element on a second printing medium is smaller than a number of the dots forming the pattern element on a first printing medium, the second printing medium being more susceptible to bleed-through of the ink than the first printing medium.