Misalignment of printing positions between print heads associated with thermal expansion is reduced without increasing a data processing load. To this end, printing element substrates in a reference head and an adjustment target head are adjusted to a target temperature, and a liquid is circulated through the print element substrates. After thermal expansion of the reference head and the adjustment target head reaches a steady state, a first printing region being a printing region of the reference head and a second printing region being a printing region of the adjustment target head in a longitudinal direction are obtained from an image printed by using all printing elements. Then, used regions to be used for actual printing are set among the printing elements arranged on the reference head and the adjustment target head based on the first printing region and the second printing region.

A liquid ejecting head unit includes an ejecting surface in which nozzles for ejecting a liquid are formed, and a first and a second circuit substrates for ejecting the liquid from the nozzles, in which a planar shape of the ejecting surface includes a first, a second and a third portions. A center line parallel to a long side of a rectangle of a minimum area surrounding the ejecting surface passes the first portion but not the second and third portions. The second and third portions are arranged adjacently to the first portion interposed therebetween. The first circuit substrate is positioned in the first and second portions. The second circuit substrate is positioned in at least one of the first and third portions.

A modular inkjet printhead includes a plurality of printhead modules arranged end on end in a row. Each printhead module includes: a substrate having a plurality of longitudinal ink supply channels; a plurality of print chips mounted on a first face of the substrate, each print chip receiving ink from a respective ink supply channel; and a plurality of fingers extending longitudinally from opposite ends of each printhead module, each finger having an ink port extending away from a second face of the substrate opposite the first face, each ink port being in fluid communication with a respective ink supply channel Each ink supply channel is connected to a respective pair of ink ports at opposite ends of each printhead module and the fingers of neighboring printhead modules are interdigitated such that the ink ports of neighboring printhead modules overlap.

A liquid ejecting apparatus includes: a first head disposed such that an arrangement angle is a first angle; a second head disposed such that an arrangement angle is a second angle, which is greater than the first angle; a first circulation mechanism circulating liquid between a first reservoir and the first head; a second circulation mechanism circulating liquid between a second reservoir and the second head; and a control unit controlling the first and the second circulation mechanisms. The control unit performs circulation cleaning, in which the liquid is circulated, on multiple heads including the first head and the second head. The amount of the liquid circulating through the first head during the circulation cleaning is a first amount, and the amount of the liquid circulating through the second head during the circulation cleaning is a second amount that is greater than the first amount.

A circuit die may include an outermost circuit layer having electrical transmission routing and an alignment target overlying the outermost circuit layer.

A printhead module includes: a monolithic substrate having alternate longitudinal slots and longitudinal ink supply channels defined through a thickness of the substrate and extending parallel with each other along a length of the substrate; and a plurality of rows of print chips mounted on a front face of the substrate, each row of print chips receiving ink only from a respective one of the ink supply channels. Each one of the longitudinal slots is configured to supply power and data only to a respective one of the rows of print chips.

There is provided a liquid ejecting unit that ejects liquid from a plurality of nozzles, in which the planar shape of the ejecting face on which the nozzles are formed is a shape in which a first portion that passes through the center line parallel to the long side of the rectangle of the minimum area including the ejecting face and a second portion that does not pass through the center line are arranged in the direction of the long side.

A liquid ejecting head including: a first liquid ejecting portion configured to eject a liquid; a second liquid ejecting portion configured to eject a liquid; a first supply flow path configured to supply the liquid to the first liquid ejecting portion and the second liquid ejecting portion; and a temperature detection element for measuring a temperature of the liquid. The first supply flow path includes a common portion to which the liquid is supplied; a first branch portion that communicates with the common portion at a communication position, and that supplies the liquid from the common portion to the first liquid ejecting portion; and a second branch portion that communicates with the common portion at the communication position, and that supplies the liquid from the common portion to the second liquid ejecting portion. The temperature detection element is disposed at a vicinity of the communication position.

A printhead module includes a plurality of rows of printhead nozzles, at least some of the rows including at least one displaced row portion, the displacement of the row portion including a component in a direction normal to that of a pagewidth to be printed, wherein the displaced row portions of at least some of the rows are different in length than the displaced row portions of at least some of the other rows.

A frame as a multi-layer steel plate is a multi-layer steel plate including a plurality of steel plates being stacked, outer peripheries of which have a plurality of sides, in which positions of the plurality of sides of the plurality of steel plates include portions located at identical positions in plan view, the plurality of steel plates are fixed to each other by welding at the plurality of sides located at the identical positions in plan view, and among the plurality of steel plates, at least one of the steel plates is processed into a shape different from a shape of other steel plates.