Coordinated printhead operation

#An inkjet printer includes a printhead with a plurality of nozzles through which ink is ejected. Neighboring nozzles on the printhead are separated from one another by a distance that is referred to as the pitch of the printhead. Drops of ink that are ejected from the nozzles may be deposited on a substrate (e.g. paper). A distance between neighboring drops that are deposited on the substrate determines the resolution of the printer (e.g. as measured in units of dots per inch).

#During the course of printing, the substrate may be moved longitudinally past a printhead bridge to which one or more printheads are mounted so as to print on various regions of the substrate. In order to enable a resolution that is greater than the resolution that is determined by the pitch of the printhead (e.g. nozzles per inch), the printhead may be moved laterally during the course of printing. Lateral movement of the printhead may enable a nozzle of the printhead to deposit a drop of ink at a lateral position on the substrate. Subsequently, after the nozzle is moved through a distance that is shorter than the printhead pitch, the same nozzle may deposit another drop at another lateral position on the substrate. Thus, the lateral distance between the two drops may be less than the pitch of the printhead.

#In some inkjet printers, e.g. in many inkjet printers that are designed for home or office use, longitudinal motion of the substrate past the bridge is halted during lateral motion of the printhead along the bridge. In other high-speed inkjet printers, such as inkjet printers that are designed to print on large substrates, the printhead may be moved along the bridge concurrently with the longitudinal motion of the substrate past the bridge.

#FIG. 1 is a schematic illustration of a printer system for application of an example of coordinated printhead operation;

#FIG. 2 is a schematic illustration of a controller of the printer system illustrated in FIG. 1;

#FIG. 3 is a flowchart depicting an example of a method for coordinated printhead operation;

#In accordance with an example of coordinated operation of printheads, an inkjet printer includes a printhead assembly that includes a plurality of printheads. The printheads of the printhead assembly are arranged in a plurality of rows. The various printheads of the printhead assembly are configured to be moved in a coordinated fashion during the course of printing on a substrate. For example, the printheads of the printhead assembly may be mounted together on a common bridge.

#During printing, the printer causes relative longitudinal motion between the substrate and the printhead assembly. The longitudinal motion may enable the printhead assembly to deposit ink (or another substance, e.g. paint or another fluid, all of which are herein referred to as ink) along an entire length of a printable area of the substrate. For example, the substrate may be conveyed longitudinally past the printhead assembly during printing. The substrate may be mounted on a drum that rotates past the printhead assembly during printing. As another example, the substrate may be placed on a bed, platform, or table that is moved past the printhead assembly during printing. In another example, the printhead assembly (e.g. a bridge on which the printhead is mounted) may be longitudinally translated past a fixed substrate during printing.

#Each printhead includes a face that contains a substantially regular array of nozzles through which ink (or another fluid) may be ejected during printing. Various operational considerations may limit the number of nozzles that may be included in a single printhead. Therefore, in order that the printhead assembly include a desired number of nozzles (e.g. a row of nozzles whose length is sufficient to cover the width of a printable area of a substrate during the course of printing), the printhead assembly includes a plurality of printheads arranged generally along a lateral direction that may be perpendicular to (or at another angle to) the longitudinal direction of relative motion between the printhead assembly and the substrate.