A printing device comprising a printing head including a plurality of nozzles configured to discharge ink to a printing medium are arranged, and a control unit configured to control discharge of the ink. The printing head is configured to discharge the ink along with scanning that is a relative movement in a predetermined direction with respect to the printing medium, and in test printing for printing a TP on the printing medium, the control unit performs control such that the ink of a first discharge amount is discharged from the nozzles when a color difference between the TP and the printing medium is greater than a predetermined threshold value, and the ink of a second discharge amount that is greater than the first discharge amount is discharged when the color difference between the TP and the printing medium is equal to or smaller than the threshold value.

A method of controlling a printer is disclosed, the printer including a number of print heads extending across a print zone, and each print head including at least one nozzle array extending in a direction of a print head axis. Each nozzle array comprises a center section of nozzles and side sections of nozzles, wherein the side sections of neighboring nozzle arrays overlap defining an overlap region and the center sections of the nozzle arrays define non-overlap regions. The method includes: printing a test pattern using at least two nozzle arrays, the test pattern comprising an interferential-type pattern printed by the side sections of the nozzle arrays in the overlap region and a reference pattern printed by the center sections of the nozzle arrays in the non-overlap regions; detecting characteristics of the printed test pattern; comparing the characteristics of the printed test pattern in the overlap region and in the non-overlap region; and deriving information concerning the alignment of nozzle arrays from the comparison

A printing system includes a print bar, a plurality of printheads installed on the print bar and an auxiliary printhead moveable parallel to the print bar. A number of first nozzles of the auxiliary printhead substitute for a number of second nozzles of the printheads during a nozzle servicing operation performed on the second nozzles.

A printing system includes a print bar, a plurality of printheads installed on the print bar and an auxiliary printhead moveable parallel to the print bar. A number of first nozzles of the auxiliary printhead substitute for a number of second nozzles of the printheads during a nozzle servicing operation performed on the second nozzles.

A liquid ejection head includes: head units arranged in a first direction; first individual heat dissipators each corresponding to one of the head units and disposed on a first side of the head unit in a second direction; and a first common heat dissipator disposed on the first side of the head units in the second direction. The first common heat dissipator extends in the first direction and shared among the head units. Each head unit includes: a unit body including an actuator; and a first driver integrated circuit disposed on the first side of the unit body in the second direction. Each of the first individual heat dissipators is disposed between the first driver integrated circuit and the first common heat dissipator of the head unit so as to be in thermal contact with the first driver integrated circuit and the first common heat dissipator.

A liquid ejection head includes: head units arranged in a first direction; first individual heat dissipators each corresponding to one of the head units and disposed on a first side of the head unit in a second direction; and a first common heat dissipator disposed on the first side of the head units in the second direction. The first common heat dissipator extends in the first direction and shared among the head units. Each head unit includes: a unit body including an actuator; and a first driver integrated circuit disposed on the first side of the unit body in the second direction. Each of the first individual heat dissipators is disposed between the first driver integrated circuit and the first common heat dissipator of the head unit so as to be in thermal contact with the first driver integrated circuit and the first common heat dissipator.

An inkjet apparatus includes a head pack including sub-head packs, at least one inkjet head coupled to each of the sub-head packs, a head pack aligner coupled to each of the sub-head packs, and including a first motor which moves each of the sub-head packs in a first rotation direction, a second motor which is disposed on the first motor and moves each of the sub-head packs in a first direction which is a longitudinal direction of each of the sub-head packs in a plan view, and a controller which controls a moving position of each of the sub-head packs and a head aligner coupled to the inkjet head and including a first adjusting member which moves the inkjet head in a second rotation direction and a second adjusting member which moves the inkjet head in a second direction which is a longitudinal direction of each of the inkjet head.

An inkjet apparatus includes a head pack including sub-head packs, at least one inkjet head coupled to each of the sub-head packs, a head pack aligner coupled to each of the sub-head packs, and including a first motor which moves each of the sub-head packs in a first rotation direction, a second motor which is disposed on the first motor and moves each of the sub-head packs in a first direction which is a longitudinal direction of each of the sub-head packs in a plan view, and a controller which controls a moving position of each of the sub-head packs and a head aligner coupled to the inkjet head and including a first adjusting member which moves the inkjet head in a second rotation direction and a second adjusting member which moves the inkjet head in a second direction which is a longitudinal direction of each of the inkjet head.

An inkjet printhead includes a two-dimensional array of drop ejectors arranged as a plurality of columns, each column including a plurality of banks, and each bank including a plurality of groups that each include a plurality of drop ejectors. The drop ejectors in each group are substantially aligned along a first direction. The groups in each bank are spaced from each other along the first direction and are offset from each other along a second direction. The banks in each column are spaced from each other along the first direction and are offset from each other along the second direction. The columns are offset from each other along the second direction. The two-dimensional array has a width W along the first direction and a length L greater than W along the second direction. Each drop ejector includes a nozzle, an ink inlet, a pressure chamber and an actuator

A method for manufacturing a printing bar unit for a printing system includes the steps of providing a support bar having a plurality of primary mounting positions, providing a plurality of exchangeable printheads having a plurality of inkjet nozzles, and releasably mounting the printheads to the support bar. Preceding the step of releasably mounting the printheads to the support bar, a plurality of reference organs are connected at the primary mounting positions to the support bar and undergo an alignment finishing process for forming a plurality of accurate secondary mounting positions, and then in a subsequent step the printheads are releasably mounted to the secondary mounting positions on the reference organs. A dimensional tolerance of the secondary mounting positions on the reference organs relative to each other is more accurate than a dimensional tolerance of the primary mounting positions on the support bar relative to each other.